JP2018107700A - Reception device and reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reception device capable of performing efficient processing as for a multiplex system using superposition coding.SOLUTION: A reception device comprises: a reception part for receiving a multiplexed signal; a first demapping part for generating a first bit likelihood string by demapping the multiplexed signal; a first decoding part for deriving a first bit string including a first error-corrected data portion and a first error-corrected error control portion by performing error control decoding; a mapping part for generating a first modulation symbol string by mapping the first bit string including the first error-corrected data portion and the first error-corrected error control portion; a subtraction part for subtracting the first modulation symbol string from the multiplexed signal; a second demapping part for generating a second bit likelihood string by demapping the multiplexed signal; and a second decoding part for deriving a second data sequence by performing error control decoding.SELECTED DRAWING: Figure 24

Description

  The present disclosure relates to a receiving apparatus that receives a multiplexed signal and derives a plurality of data sequences from the multiplexed signal.

  A multiplexing method using superposition coding is known as a multiplexing method for multiplexing and transmitting a plurality of data sequences (Non-patent Document 1). As other multiplexing methods, time division multiplexing and frequency division multiplexing are known (Non-patent Document 2).

  The multiplexing scheme using superposition coding is suitable for multiplexing a plurality of data sequences that require different noise immunity (reception immunity) compared to time division multiplexing and frequency division multiplexing. A multiplexing scheme using superposition coding is also known by the name of layer division multiplexing. In addition, a multiplexing scheme using superposition coding is also known as non-orthogonal division multiple access (NOMA) applied to multiple access.

  In a multiplexing scheme using superposition coding, a transmission apparatus superimposes a plurality of modulation symbols obtained by modulating a plurality of data sequences with a predetermined power distribution, and transmits the result. The receiving apparatus performs demodulation of a plurality of modulation symbols multiplexed by superimposition coding in order from the modulation symbol of the layer having higher noise tolerance until the demodulation of the modulation symbol of the layer to which the desired data series belongs is completed.

  Specifically, the receiving apparatus estimates a data sequence by demodulating a modulation symbol of a layer having the highest noise tolerance. Then, if the desired data sequence is not estimated, the receiving device generates a replica of the modulation symbol from the other estimated data sequence, cancels the replica from the received signal, A new data series is estimated by demodulating the modulation symbols. The receiving apparatus repeats these processes until a desired data series is estimated.

Seokhyun YOON and Donghee KIM, Performance of Superposition Coded Broadcast / Unicast Service Overlay Systems, IEICE Transactions on Communations. E91-B, no. 9 Thomas M.M. Cover, Broadcast Channels, IEEE Transactions on Information Theory, vol. IT-18, no. 1 J. et al. Zollner and N.M. Login, Optimization of High-order Non-uniform QAM Contests, IEEE International Symposium on Broadband Multimedia Systems and Broadcasting 2013

  In a multiplexing scheme using superposition coding, processing related to a plurality of data sequences may not be performed efficiently.

  For example, in a multiplexing method using superposition coding, a processing delay occurs due to a process of sequentially decoding a plurality of multiplexed data series. In addition, in the multiplexing method using superposition coding, it is necessary for the receiving apparatus to include computing resources and the like for remodulating the previously decoded data series. In addition, the receiving apparatus decodes and remodulates the previous data series, and stores a memory resource or the like for holding a received symbol used for decoding the next data series until a modulation symbol sequence of the previous data series is obtained. It is necessary to prepare.

  In addition, in a multiplexing scheme using superposition coding, there is a possibility that the transmission capacity may be reduced because a plurality of superposed data series influence each other.

  The present disclosure provides an example of an embodiment that solves the above-described problem in a multiplexing scheme using superposition coding. However, the present disclosure also provides an aspect that solves some but not all of the above problems, or an aspect that solves problems that are different from the above problems.

  A receiving apparatus according to an aspect of the present disclosure is a multiplex that is a signal in which a plurality of data sequences including a first data sequence of a first hierarchy and a second data sequence of a second hierarchy are multiplexed by superposition coding. A receiving device for receiving a signal, a receiving unit for receiving the multiplexed signal, a first data portion corresponding to the first data sequence by demapping the multiplexed signal, and a first error A first demapping unit that generates a first bit likelihood sequence including a control portion, and performing error control decoding on the first bit likelihood sequence, thereby correcting the first error. A first decoding unit for deriving a first bit string including a data part and the error-corrected first error control part; the error-corrected first data part; and the error-corrected first part And the first error control portion. By mapping the bit sequence, a mapping unit that generates a first modulation symbol sequence, a delay unit that delays the multiplexed signal received by the receiving unit, and the multiplexed signal delayed by the delay unit, A subtraction unit for subtracting a first modulation symbol sequence; a second data portion corresponding to the second data sequence by demapping the multiplexed signal from which the first modulation symbol sequence has been subtracted; A second demapping unit that generates a second bit likelihood sequence including a second error control portion, and error correction decoding is performed on the second bit likelihood sequence to perform error correction A second decoding unit for deriving the second data sequence including the second data portion.

  These general or specific aspects may be realized by a non-transitory recording medium such as a system, apparatus, method, integrated circuit, computer program, or computer-readable CD-ROM. The present invention may be realized by any combination of a method, an integrated circuit, a computer program, and a recording medium.

  The receiving device or the like according to one aspect of the present disclosure can perform efficient processing regarding a multiplexing scheme using superposition coding.

  Further advantages and effects in one aspect of the present disclosure will become apparent from the specification and drawings. These advantages and effects are provided by the features described in the specification and drawings, but some, not all of these advantages and effects, are described in the specifications and drawings. It may be provided by some of the features.

FIG. 1 is a block diagram illustrating a configuration example of a transmission apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration example of the receiving apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a transmission capacity by superposition coding. FIG. 4 is a diagram illustrating an example of a QPSK constellation. FIG. 5 is a diagram illustrating an example of a non-uniform constellation. FIG. 6 is a diagram showing a transmission capacity by superposition coding using QPSK and Nu-256QAM. FIG. 7 is a block diagram illustrating a first configuration example of the receiving apparatus according to the second embodiment. FIG. 8 is a diagram illustrating an example of a superimposed constellation. FIG. 9 is a flowchart illustrating a first reception operation example in the second embodiment. FIG. 10 is a diagram illustrating an example of a simulation result for comparing sequential decoding and parallel decoding in superposition coding. FIG. 11 is a block diagram illustrating a second configuration example of the receiving apparatus according to the second embodiment. FIG. 12 is a flowchart illustrating a second reception operation example in the second embodiment. FIG. 13 is a block diagram illustrating a first configuration example of the transmission apparatus according to the third embodiment. FIG. 14 is a block diagram illustrating a second configuration example of the transmission apparatus according to the third embodiment. FIG. 15 is a block diagram illustrating a third configuration example of the transmission apparatus according to the third embodiment. FIG. 16 is a block diagram illustrating a first configuration example of the receiving apparatus according to the third embodiment. FIG. 17 is a block diagram illustrating a second configuration example of the receiving apparatus according to the third embodiment. FIG. 18 is a block diagram illustrating a third configuration example of the receiving apparatus according to the third embodiment. FIG. 19 is a block diagram illustrating a fourth configuration example of the receiving apparatus according to the third embodiment. FIG. 20 is a diagram illustrating an example of a modified superimposed constellation according to the third embodiment. FIG. 21 is a flowchart illustrating an exemplary transmission operation in the third embodiment. FIG. 22 is a flowchart illustrating an exemplary reception operation in the third embodiment. FIG. 23 is a diagram illustrating an example of a simulation result for comparing sequential decoding and parallel decoding in modified superposition coding. FIG. 24 is a block diagram illustrating a first configuration example of the receiving apparatus according to the fourth embodiment. FIG. 25 is a conceptual diagram showing an example of the replica generation operation in the first embodiment. FIG. 26 is a conceptual diagram illustrating an example of a replica generation operation according to the fourth embodiment. FIG. 27 is a block diagram illustrating a second configuration example of the receiving apparatus according to the fourth embodiment. FIG. 28 is a block diagram illustrating a third configuration example of the receiving apparatus in the fourth embodiment. FIG. 29 is a block diagram illustrating a fourth configuration example of the receiving apparatus in the fourth embodiment. FIG. 30 is a block diagram illustrating a fifth configuration example of the receiving apparatus in the fourth embodiment. FIG. 31 is a block diagram illustrating a sixth configuration example of the receiving apparatus in the fourth embodiment. FIG. 32 is a block diagram illustrating a first configuration example of the receiving apparatus according to the fifth embodiment. FIG. 33 is a conceptual diagram illustrating an example of a replica generation operation according to the fifth embodiment. FIG. 34 is a block diagram illustrating a second configuration example of the receiving apparatus according to the fifth embodiment. FIG. 35 is a block diagram illustrating a third configuration example of the receiving apparatus in the fifth embodiment. FIG. 36 is a block diagram illustrating a fourth configuration example of the receiving apparatus in the fifth embodiment. FIG. 37 is a block diagram illustrating a fifth configuration example of the receiving apparatus in the fifth embodiment. FIG. 38 is a block diagram illustrating a sixth configuration example of the receiving apparatus in the fifth embodiment.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. It should be noted that the embodiments and the like described below show a comprehensive or specific example. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments and the like are examples, and are not intended to limit the scope of the claims. In addition, among the constituent elements in the following embodiments and the like, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

  Also, encoding may mean error control encoding. Error control coding is also called error correction coding. Decoding may mean error control decoding. Error control decoding is also called error correction decoding or error correction. Also, unknown may mean indeterminate. Also, transmission may mean transmission.

(Embodiment 1)
In this embodiment, a case will be described in which a plurality of data sequences are multiplexed and transmitted in a plurality of layers by a multiplexing scheme using superposition coding.

  In a plurality of embodiments including this embodiment, a case where two data series are multiplexed and transmitted in two different layers will be described as an example in order to simplify the description without impairing generality. . However, the multiplexing method described in a plurality of embodiments including this embodiment can be applied even when three or more data sequences are multiplexed and transmitted in three or more different layers.

  In a plurality of embodiments including the present embodiment, the first layer to which the first data series belongs is used as a layer having higher noise resistance than the second layer to which the second data series belongs. .

  FIG. 1 shows an example of a configuration of a transmission apparatus 100 that multiplexes and transmits two data sequences in two layers using superposition coding. The configuration and operation of the transmission apparatus 100 will be described with reference to FIG.

  The transmitting apparatus 100 includes an encoding unit 111, an interleaving unit 112, a mapping unit 113, a multiplying unit 114, an encoding unit 121, an interleaving unit 122, a mapping unit 123, a multiplying unit 124, an adding unit 130, and an RF unit (Radio Frequency unit). 140. Each component may be a dedicated or general purpose circuit. The multiplication unit 114, the multiplication unit 124, and the addition unit 130 may be expressed as a superposition unit as a whole. The RF unit 140 can also be expressed as a transmission unit. The RF unit 140 may include an antenna.

  The encoding unit 111 performs encoding based on the first error control encoding method on the input first data series to generate a first bit string. The interleaving unit 112 rearranges the bit order of the first bit string generated by the encoding unit 111 based on the first rearrangement rule. This rearrangement is also called interleaving.

  Mapping section 113 performs mapping processing according to the first mapping scheme (first modulation scheme) on the first bit string rearranged by interleaving section 112, and is configured with a plurality of first modulation symbols. A first modulation symbol sequence is generated. In the mapping process according to the first mapping method, the mapping unit 113 converts the first bit string of the plurality of signal points in the first constellation according to the value of the bit group for each bit group of the first number of bits. Map to any one of these signal points.

  The encoding unit 121 performs encoding based on the second error control encoding method on the input second data series to generate a second bit string. The interleaving unit 122 rearranges the bit order of the second bit string generated by the encoding unit 121 based on the second rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 123 performs mapping processing according to the second mapping scheme (second modulation scheme) on the second bit string rearranged by the interleaving unit 122, and is configured with a plurality of second modulation symbols. Second modulation symbol sequence is generated. In the mapping process according to the second mapping method, the mapping unit 123 converts the second bit string into a plurality of signal points in the second constellation according to the value of the bit group for each bit group of the second number of bits. Map to any one of these signal points.

  When PSK modulation such as BPSK and QPSK, or QAM modulation such as 16QAM and 64QAM is used as the mapping method, the modulation symbol indicates, for example, the size of the in-phase component and the imaginary number indicates the size of the quadrature component. It can be represented by a complex number. When PAM modulation is used as the mapping method, the modulation symbol can be represented by a real number.

Multiplier 114, a first multiplying the amplitude coefficient a ₁ for the first modulation symbol of the first modulation symbol sequence. Multiplying unit 124, second multiplying the amplitude coefficient a ₂ for the second modulation symbols of the second modulation symbol sequence. Adding section 130, a first modulation symbol, the second amplitude coefficient a ₂ is superimposed and the second modulation symbols multiplied, a plurality of superimposed modulation symbols first amplitude coefficient a ₁ is multiplied Is generated.

  The RF unit 140 transmits the generated superimposed modulation symbol sequence as a signal. Specifically, the RF unit 140 generates a radio frequency band signal as a signal corresponding to the superimposed modulation symbol sequence from the superimposed modulation symbol sequence generated by the adding unit 130, and transmits the radio frequency band signal from the antenna. Send.

  That is, the superimposing unit composed of the multiplying unit 114, the multiplying unit 124, and the adding unit 130 superimposes the first modulation symbol sequence and the second modulation symbol sequence with a predetermined amplitude ratio, thereby generating the first data A multiplexed signal that is a signal in which the sequence and the second data sequence are multiplexed is generated. Then, the RF unit 140 transmits a multiplexed signal. The multiplexed signal corresponds to a superimposed modulation symbol sequence. Further, the predetermined amplitude ratio may be 1: 1, and the multiplication process may be omitted.

  FIG. 2 receives a signal in which two data sequences are multiplexed in two layers using superposition coding, sequentially decodes, and acquires (extracts) both or one of the two multiplexed data sequences. 2 shows an example of a configuration of a receiving device 200 that can be used. The configuration and operation of the receiving apparatus 200 will be described with reference to FIG.

  The receiving apparatus 200 includes an RF unit 230, a demapping unit 211, a deinterleaving unit 212, a decoding unit 213, an encoding unit 214, an interleaving unit 215, a mapping unit 216, a multiplication unit 217, a delay unit 218, a subtraction unit 219, and a demapping. Unit 221, deinterleave unit 222, and decoding unit 223. Each component may be a dedicated or general purpose circuit.

  Demapping unit 211, deinterleaving unit 212, decoding unit 213, encoding unit 214, interleaving unit 215, mapping unit 216, multiplication unit 217, delay unit 218, subtraction unit 219, demapping unit 221, deinterleaving unit 222 and decoding The unit 223 can be expressed as a derivation unit as a whole. The RF unit 230 can also be expressed as a receiving unit. The RF unit 230 may include an antenna.

  The receiving apparatus 200 receives the multiplexed signal transmitted from the transmitting apparatus 100 with an antenna and inputs it to the RF unit 230. That is, the RF unit 230 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 230 is also expressed as a received signal, and corresponds to the superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 230 generates a baseband received signal from the received signal in the radio frequency band.

The demapping unit 211 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. For example, a first constellation for demapping the amplitude coefficients a ₁ are reflected.

  The deinterleaving unit 212 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 213 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence rearranged by deinterleaving section 212, and outputs the decoding result as a first data sequence. .

  Here, the demapping unit 211 treats a component corresponding to the second modulation symbol of the second data series as an unknown signal (noise) in the received signal corresponding to the superimposed modulation symbol sequence, and performs the first mapping Demapping is performed based on the first constellation of the scheme.

  When only the first data series is an acquisition target, the receiving device 200 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, the receiving device 200 acquires the second data series. Therefore, the following processing is performed.

  The encoding unit 214 performs encoding based on the first error control encoding method on the first data series acquired by the decoding unit 213 to generate a first bit string. The interleaving unit 215 rearranges the bit order of the first bit string generated by the encoding unit 214 based on the first rearrangement rule. This rearrangement is also called interleaving.

The mapping unit 216 performs a mapping process according to the first mapping method on the first bit sequence rearranged by the interleaving unit 215, and a first modulation symbol sequence composed of a plurality of first modulation symbols Is generated. Multiplying unit 217 multiplies the first amplitude coefficient a ₁ in the first modulation symbol sequence mapping unit 216 outputs.

  The delay unit 218 outputs the reception signal output from the RF unit 230 until the multiplication unit 217 outputs the reproduced first modulation symbol sequence after the RF unit 230 outputs the baseband reception signal. Delay.

The subtracting unit 219 subtracts the first modulation symbol string multiplied by the _first amplitude coefficient a ₁ by the multiplying unit 217 from the reception signal delayed by the delay unit 218. As a result, the subtraction unit 219 removes the component corresponding to the first modulation symbol from the received signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 219 outputs a signal in which a component corresponding to the second modulation symbol and noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The demapping unit 221 demaps the signal output from the subtracting unit 219 based on the second constellation of the second mapping scheme, and generates a second bit likelihood sequence. For example, the amplitude coefficient a ₂ is reflected in the second constellation for demapping.

  The deinterleaving unit 222 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 223 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 222, and outputs the decoding result as a second data sequence .

  As described above, the receiving device 200 acquires both or one of the first data series and the second data series from the signal received by the antenna.

<Superimposition coding>
Next, superposition coding will be described.

Using the signal power P _s (W), the noise power P _n (W), and the transmission bandwidth B (Hz), the transmission capacity C _T (bit / s) is given by Equation 1 as the Shannon limit.

  The transmission capacity C (bit / s / Hz) per 1 Hz normalized by the transmission bandwidth is given by Equation 2.

  Hereinafter, “transmission capacity per 1 Hz” is simply referred to as “transmission capacity”.

In the superposition coding of the first data series and the second data series, the signal power P _s1 (W) of the first layer corresponding to the first data series and the second corresponding to the second data series The signal power P _s2 (W) and the entire signal power P _s (W) satisfy the following condition: P _s = P _s1 + P _s2

When demodulating the first layer, receiving apparatus 200 regards the component of the modulation symbol of the second layer as an unknown component superimposed on the modulation symbol of the first layer, that is, noise. Therefore, the transmission capacity C ₁ of the first layer is given by Equation 3.

When the receiving apparatus 200 demodulates the second layer, the modulation symbol component of the first layer is already removed from the received signal. For this reason, the transmission capacity C2 of the _second layer is given by Equation 4.

The sum of the transmission capacity C ₁ of the first layer and the transmission capacity C ₂ of the second layer matches the Shannon limit as shown in Equation 5.

In the present embodiment, the signal power P _s1 of the first layer corresponding to the first data series is proportional to the square of the first amplitude coefficient a _{1 and} the second power corresponding to the second data series. hierarchy signal power _{P s2} is proportional to the second square of the amplitude coefficient _{a 2.} The distribution of signal power for a plurality of layers is determined by the amplitude coefficient multiplied by the modulation symbol of each layer.

FIG. 3 shows an example of the simulation result of each transmission capacity when the ratio of the signal power P _s1 of the first layer and the signal power P _s2 of the second layer is P _s1 : P _s2 = 2: 1. . 3, the horizontal axis represents the signal power _{P s} to noise power _{P n} ratio (SNR) in dB (decibels), the vertical axis represents the transmission capacity. In FIG. 3, the alternate long and short dash line indicates the transmission capacity C ₁ of the first hierarchy, the broken line indicates the transmission capacity C ₂ of the second hierarchy, and the solid line indicates the transmission capacity C ₁ of the first hierarchy and the second hierarchy. It shows the total transmission capacity of the transmission capacity C _2.

  The SNR means a signal power to noise power ratio and is also called a signal to noise power ratio or a signal to noise ratio.

<Non-uniform constellation>
In the present embodiment, transmitting apparatus 100 can use any mapping scheme as the first mapping scheme and the second mapping scheme. The receiving apparatus 200 demodulates the first layer while the second modulation symbol of the second layer is unknown. Therefore, a mapping method such as QPSK, which mainly targets a low SNR, is suitable as the first mapping method.

  FIG. 4 shows an example of a QPSK constellation. Specifically, four signal points of QPSK are plotted on a complex plane in which the horizontal axis is the real part (real number component) and the vertical axis is the imaginary part (imaginary number component). In QPSK, a bit group (00, 01, 10 or 11) is associated with a complex modulation symbol based on the constellation shown in FIG.

  On the other hand, the second layer is demodulated with the modulation symbols of the first layer already removed. Therefore, the second mapping method may be a mapping method using a multi-value constellation targeting a high SNR.

  In recent years, a non-uniform constellation as described in Non-Patent Document 3 has attracted attention as a multi-value constellation. The non-uniform constellation is a constellation composed of signal points arranged at non-uniform intervals, unlike a uniform constellation composed of signal points arranged at uniform intervals like the conventional QAM. The mapping method using the non-uniform constellation may improve the transmission capacity compared to the mapping method using the uniform constellation.

  FIG. 5 shows an example of a non-uniform constellation (Nu-256QAM) composed of 256 signal points. In FIG. 5, 256 signal points of a non-uniform constellation are plotted on a complex plane in which the horizontal axis is the real part and the vertical axis is the imaginary part.

  In the multiplexing scheme using superposition coding, an example in which QPSK shown in FIG. 4 is used as the first mapping scheme and Nu-256QAM shown in FIG. 5 is used as the second mapping scheme will be described below. .

An example of a simulation result of each transmission capacity when the ratio of the signal power P _s1 of the first layer and the signal power P _s2 of the second layer is P _s1 : P _s2 = 2: 1 is shown in FIG. . 6, the horizontal axis represents the signal power _{P s} to noise power _{P n} ratio (SNR) in dB (decibels), the vertical axis represents the transmission capacity. In FIG. 6, the alternate long and short dash line indicates the transmission capacity C ₁ of the first layer, and the broken line indicates the transmission capacity C ₂ of the second layer. A combination of QPSK and Nu-256QAM provides a transmission capacity close to the limit shown in FIG.

  As described above, according to the present embodiment, transmitting apparatus 100 can multiplex and transmit a plurality of data sequences with high efficiency by a multiplexing scheme using superposition coding. The receiving apparatus 200 can receive a plurality of data sequences multiplexed with high efficiency by a multiplexing method using superposition coding. Furthermore, the transmission device 100 and the reception device 200 can improve the transmission capacity using a non-uniform constellation.

  Note that the rearrangement (interleaving and deinterleaving) suppresses the influence when consecutive errors occur. Further, rearrangement (interleaving and deinterleaving) controls the correspondence between the bits constituting the code word of the error correction code, the modulation symbols, and the bits constituting the modulation symbols. However, rearrangement (interleaving and deinterleaving) may be omitted.

  That is, the interleaving unit 112 and the interleaving unit 122 are arbitrary components and may not be included in the transmission device 100. Similarly, the deinterleaving unit 212, the interleaving unit 215, and the deinterleaving unit 222 are optional components and may not be included in the reception device 200.

  However, interleaving and deinterleaving constitute a pair. Therefore, basically, when transmitting apparatus 100 includes interleaving section 112 and interleaving section 122, receiving apparatus 200 includes deinterleaving section 212, interleaving section 215, and deinterleaving section 222. On the other hand, when transmitting apparatus 100 does not include interleaving section 112 and interleaving section 122, receiving apparatus 200 does not include deinterleaving section 212, interleaving section 215, and deinterleaving section 222.

Further, the amplitude coefficient a ₁ may be reflected in the mapping in the mapping unit 216 of the receiving device 200. In this case, the multiplication process may be omitted in the reception apparatus 200, and the reception apparatus 200 may not include the multiplication unit 217.

  Further, the error control coding of the first data sequence and the second data sequence may be performed by an external device different from the transmission device 100. In this case, error control coding may be omitted in transmitting apparatus 100. The transmission apparatus 100 may not include the encoding unit 111 and the encoding unit 121.

(Embodiment 2)
<Parallel decoding of signals obtained by superposition coding>
In the present embodiment, a reception method for parallel decoding of signals obtained by superposition coding will be described. The configuration of the transmission apparatus is the same as that of the transmission apparatus 100 shown in FIG. In parallel decoding in superposition coding, the receiving apparatus does not remove the component of the modulation symbol sequence of the first layer included in the received signal, but the component of the modulation symbol sequence of the first layer is unknown signal (noise). And the second layer is decoded.

  In FIG. 7, it is possible to receive a signal in which two data series are multiplexed in two layers using parallel coding and decode it in parallel to obtain both or one of the two multiplexed data series. 1 shows an example of the configuration of a simple receiving device 300. The configuration and operation of the receiving apparatus 300 will be described with reference to FIG.

  The receiving apparatus 300 includes an RF unit 330, a demapping unit 310, a deinterleaving unit 312, a decoding unit 313, a deinterleaving unit 322, and a decoding unit 323. Each component may be a dedicated or general purpose circuit. The demapping unit 310, the deinterleaving unit 312, the decoding unit 313, the deinterleaving unit 322, and the decoding unit 323 may be expressed as a derivation unit as a whole. The RF unit 330 can also be expressed as a receiving unit. The RF unit 330 may include an antenna.

  The receiving device 300 receives the multiplexed signal transmitted from the transmitting device 100 with an antenna and inputs it to the RF unit 330. That is, the RF unit 330 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 330 can also be expressed as a received signal. The RF unit 330 generates a baseband reception signal from the reception signal in the radio frequency band.

  The demapping unit 310 demaps the baseband received signal and generates a first bit likelihood sequence and a second bit likelihood sequence. For example, the demapping unit 310 performs demapping based on a superposition constellation indicating the arrangement of signal points of superposition modulation symbols in which the first modulation symbol and the second modulation symbol are superposed using superposition coding. .

Superimposed constellation, first constellation of the first mapping scheme, a second constellation of a second mapping method, dependent on the first amplitude coefficient a ₁ and the first amplitude coefficient a ₂ and the like.

  FIG. 8 shows an example of a superimposed constellation. Specifically, the QPSK constellation shown in FIG. 4 and the Nu-256QAM constellation shown in FIG. 5 are combined. More specifically, Nu-256QAM constellations (256 signal points) are arranged in each of the four regions on the complex plane in accordance with the four signal points of the QPSK constellation. These four regions corresponding to the Nu-256QAM constellation may partially overlap.

  The demapping unit 310 performs demapping based on a superposed constellation as shown in FIG. That is, demapping section 310 generates a first bit likelihood sequence when the modulation symbol sequence of the second layer is unknown, and generates a second bit likelihood when the modulation symbol sequence of the first layer is unknown. Generate a degree sequence.

  Note that the demapping unit 310 uses the first constellation of the first mapping scheme for generating the first bit likelihood sequence, and for generating the second bit likelihood sequence, the above-described superposed constellation. May be used.

  When the first constellation is used for the generation of the first bit likelihood sequence, the demapping unit 310 compares the first constellation with the first case where the superimposed constellation is also used for the generation of the first bit likelihood sequence. It is possible to reduce the number of signal points that are considered in generating the bit likelihood sequence. Therefore, in this case, the demapping unit 310 can reduce the calculation amount.

  Further, for example, the demapping unit 310 includes a first demapping unit that generates a first bit likelihood sequence by demapping the received signal, and a second bit likelihood by demapping the received signal. This corresponds to the second demapping unit that generates a column. The demapping unit 310 generates a first bit likelihood sequence by demapping the received signal, and generates a second bit likelihood sequence by demapping the received signal. And a second demapping unit.

  The deinterleaving unit 312 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 313 performs decoding processing based on the first error control coding scheme on the first bit likelihood sequence rearranged by deinterleaving section 312 and outputs the decoding result as a first data sequence. .

  The deinterleaving unit 322 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 323 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 322, and outputs the decoding result as a second data sequence .

  Note that rearrangement (deinterleaving) may be omitted as in the first embodiment. That is, the deinterleaving unit 312 and the deinterleaving unit 322 are arbitrary components and may not be included in the receiving apparatus 300.

  However, interleaving and deinterleaving constitute a pair. Therefore, basically, when transmitting apparatus 100 includes interleaving section 112 and interleaving section 122, receiving apparatus 300 includes deinterleaving section 312 and deinterleaving section 322. On the other hand, when transmitting apparatus 100 does not include interleaving section 112 and interleaving section 122, receiving apparatus 300 does not include deinterleaving section 312 and deinterleaving section 322.

  FIG. 9 is a flowchart illustrating an operation example of the receiving apparatus 300. First, the RF unit 330 receives a multiplexed signal that is a signal in which the first data series and the second data series are multiplexed (S101).

  Next, the demapping unit 310 generates a first bit likelihood sequence of the first data series by demapping the multiplexed signal (S102). Further, the demapping unit 310 generates a second bit likelihood sequence of the second data series by demapping the multiplexed signal (S103). The deinterleaving unit 312 may deinterleave the generated first bit likelihood sequence. The deinterleaving unit 322 may deinterleave the generated second bit likelihood sequence.

  Then, the decoding unit 313 derives a first data series by performing error control decoding on the first bit likelihood sequence (S104). Also, the decoding unit 323 derives a second data series by performing error control decoding on the second bit likelihood sequence (S105).

  Basically, processing for the first bit likelihood sequence (generation, deinterleaving and error control decoding) and processing for the second bit likelihood sequence (generation, deinterleaving and error control decoding) are performed in parallel. Done.

  In the receiving apparatus 300 that performs parallel decoding illustrated in FIG. 7, the decoding performance for the second layer is degraded as compared with the receiving apparatus 200 that performs sequential decoding illustrated in FIG. 2.

The figure shows an example of the simulation result of the transmission capacity of the second layer when the ratio of the signal power P _s1 of the first layer and the signal power P _s2 of the second layer is P _s1 : P _s2 = 2: 1. 10 shows. 10, the horizontal axis represents the signal power _{P s} to noise power _{P n} ratio (SNR) in dB (decibels), the vertical axis represents the transmission capacity. In FIG. 10, the solid line indicates the transmission capacity of the second layer when performing sequential decoding, and the broken line indicates the transmission capacity of the second layer when performing parallel decoding.

  As shown in FIG. 10, when parallel decoding is performed, the SNR required for the same transmission capacity is increased in the second layer decoding as compared with the case of performing sequential decoding. Transmission capacity decreases.

  As described above, receiving device 300 that performs parallel decoding in the present embodiment is degraded in decoding performance regarding the second data sequence transmitted in the second layer, as compared with receiving device 200 that performs sequential decoding. . However, it is possible to reduce the configuration necessary for the decoding of the second hierarchy.

  Specifically, compared with receiving apparatus 200 that performs successive decoding shown in FIG. 2, receiving apparatus 300 has an encoding section 214, an interleaving section 215, a mapping for reproducing a modulation symbol string of the first layer. The unit 216 and the multiplication unit 217 are not necessary. In addition, the delay unit 218 for delaying the received signal and the subtracting unit 219 for removing the first-level modulation symbol component reproduced from the received signal are not necessary.

  Therefore, the circuit scale can be reduced. In addition, the receiving apparatus 300 can reduce the amount of calculation compared to the receiving apparatus 200, and can reduce power consumption.

  Furthermore, receiving apparatus 200 that performs successive decoding shown in FIG. 2 demodulates the first layer of the received signal to obtain a first data sequence, and obtains a first modulation symbol from the obtained first data sequence. After generating the sequence, demodulation of the second layer of the received signal is started to obtain the second data series. On the other hand, since receiving apparatus 300 that performs parallel decoding in this embodiment can simultaneously acquire the first data series and the second data series in parallel, the processing delay can be reduced. Can do.

  Further, the reception apparatus may observe the SNR of the received signal, and switch the decoding process so that parallel decoding is performed when the SNR is high, and sequential decoding is performed when the SNR is low.

  In this case, for example, the receiving apparatus 200 illustrated in FIG. 2 includes a control unit that switches between sequential decoding and parallel decoding according to the SNR. The control unit may be included in the RF unit 230 or the demapping unit 221. Further, the demapping unit 221 includes a configuration for performing the operation of the demapping process based on the superposed constellation described as the operation of the demapping unit 310 in FIG. 7 in addition to the demapping process based on the second constellation.

  Then, the demapping unit 221 switches between a demapping process based on the second constellation for the signal output from the subtracting unit 219 and a demapping process based on the superimposed constellation for the signal output from the RF unit 230. For example, the demapping unit 221 switches these demapping processes in accordance with a control signal from the control unit.

  FIG. 11 shows an example of the configuration of a receiving apparatus 400 that selectively performs parallel decoding and sequential decoding. The receiving apparatus 400 includes an RF unit 430, a demapping unit 411, a deinterleaving unit 412, a decoding unit 413, an encoding unit 414, an interleaving unit 415, a mapping unit 416, a multiplication unit 417, a delay unit 418, a subtraction unit 419, and a demapping. Unit 421, deinterleave unit 422, and decoding unit 423. A plurality of components of the receiving device 400 illustrated in FIG. 11 and a plurality of components of the receiving device 200 illustrated in FIG. 2 are basically the same.

  However, the demapping unit 421 of the receiving apparatus 400 performs a demapping process based on the superposed constellation in addition to the demapping process based on the second constellation of the second mapping scheme. For example, the demapping unit 421 performs processing for demapping the signal output from the subtraction unit 419 based on the second constellation, and processing for demapping the signal output from the RF unit 430 based on the superimposed constellation. Are switched according to the SNR.

  In addition, in the example of FIG. 11, the control unit that switches between sequential decoding and parallel decoding according to the SNR is omitted, but may be included in the demapping unit 421 or may be included in the RF unit 430. However, it may be included in the receiving apparatus 400 as a new component.

  FIG. 12 is a flowchart illustrating an operation example of the reception device 400. First, the RF unit 430 receives a multiplexed signal that is a signal in which the first data series and the second data series are multiplexed (S201). Then, the RF unit 430 determines whether or not the multiplexed signal satisfies a predetermined standard. For example, the predetermined criterion is that the SNR is higher than a predetermined threshold.

  Here, when the multiplexed signal satisfies a predetermined criterion (Yes in S202), the demapping unit 411 generates the first bit likelihood sequence of the first data series by demapping the multiplexed signal ( S203). Further, the demapping unit 421 generates a second bit likelihood sequence of the second data series by demapping the multiplexed signal (S204). The deinterleaving unit 412 may deinterleave the generated first bit likelihood sequence. The deinterleaving unit 422 may deinterleave the generated second bit likelihood sequence.

  Then, the decoding unit 413 derives a first data series by performing error control decoding on the first bit likelihood sequence (S205). In addition, the decoding unit 423 derives a second data series by performing error control decoding on the second bit likelihood sequence (S206).

  These operations (S203 to S206) are basically the same as the operations (S102 to S105) shown in FIG.

  On the other hand, when the multiplexed signal does not satisfy the predetermined criterion (No in S202), the demapping unit 411 generates the first bit likelihood sequence of the first data series by demapping the multiplexed signal ( S207). The deinterleaving unit 412 may deinterleave the generated first bit likelihood sequence. Next, the decoding unit 413 derives a first data series by performing error control decoding on the first bit likelihood sequence (S208).

Next, the encoding unit 414 generates a first bit string by performing error control encoding on the first data series (S209). The interleaving unit 415 may interleave the generated first bit string. Next, the mapping unit 416 generates a first modulation symbol sequence by mapping the first bit sequence (S210). Multiplying unit 417, the first modulation symbol sequence may be multiplied by the amplitude coefficient a _1.

  Also, the delay unit 418 delays the multiplexed signal until the first modulation symbol sequence is generated (S211). Then, the subtraction unit 419 subtracts the first modulation symbol sequence from the multiplexed signal (S212).

  Next, the demapping unit 421 generates a second bit likelihood sequence by demapping the multiplexed signal from which the first modulation symbol sequence is subtracted (S213). The deinterleaving unit 422 may deinterleave the generated second bit likelihood sequence. Next, the decoding unit 423 derives a second data series by performing error control decoding on the second bit likelihood sequence (S214).

  Thereby, when the SNR is high, the receiving apparatus 400 can perform parallel decoding, thereby reducing the amount of calculation and reducing power consumption. Further, when the SNR is high, the receiving apparatus 400 can reduce the processing delay by performing parallel decoding. On the other hand, when the SNR is low, there is a high possibility that the receiving apparatus 400 can decode the second data series correctly by performing sequential decoding.

  Basically, the first mapping method and the second mapping method in the present embodiment are the same as the first mapping method and the second mapping method in the first embodiment. That is, basically, the first constellation and the second constellation in the present embodiment are the same as the first constellation and the second constellation in the first embodiment. For the second mapping scheme, a uniform constellation may be used, or a non-uniform constellation may be used.

(Embodiment 3)
<Modified superposition coding (modified superposition coding)>
In the present embodiment, a method of multiplexing and transmitting a plurality of data sequences using modified superposition coding (modified superposition coding) obtained by modifying the above-described superposition coding will be described.

  FIG. 13 shows an example of a configuration of transmitting apparatus 500 that multiplexes and transmits two data sequences in two layers using modified superposition coding. The configuration and operation of the transmission apparatus 500 will be described with reference to FIG.

  Transmitting apparatus 500 includes encoding section 511, interleaving section 512, mapping section 513, multiplication section 514, encoding section 521, interleaving section 522, mapping section 523, conversion section 525, multiplication section 524, addition section 530, and RF section 540. Is provided. Each component may be a dedicated or general purpose circuit. The multiplication unit 514, the multiplication unit 524, and the addition unit 530 can be expressed as a superposition unit as a whole. The RF unit 540 can also be expressed as a transmission unit. The RF unit 540 may include an antenna.

  The encoding unit 511 performs encoding based on the first error control encoding method on the input first data series to generate a first bit string. The interleaving unit 512 rearranges the bit order of the first bit string generated by the encoding unit 511 based on the first rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 513 performs mapping processing according to the first mapping method on the first bit sequence rearranged by the interleaving unit 512, and a first modulation symbol sequence composed of a plurality of first modulation symbols Is generated. In the mapping process according to the first mapping method, the mapping unit 513 converts the first bit string into a plurality of signal points in the first constellation according to the value of the bit group for each bit group of the first number of bits. Map to any one of these signal points.

  When PSK modulation such as BPSK and QPSK, or QAM modulation such as 16QAM and 64QAM is used as the first mapping method, the first modulation symbol, for example, indicates the magnitude of the in-phase component, and the imaginary number is orthogonal It can be represented by a complex number indicating the magnitude of the component. In addition, when PAM modulation is used as the first mapping scheme, the first modulation symbol can be represented by a real number.

  The encoding unit 521 performs encoding based on the second error control encoding method on the input second data series to generate a second bit string. The interleaving unit 522 rearranges the bit order of the second bit string generated by the encoding unit 521 based on the second rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 523 performs mapping processing according to the second mapping method on the second bit sequence rearranged by the interleaving unit 522, and a second modulation symbol sequence composed of a plurality of second modulation symbols Is generated. In the mapping process according to the second mapping method, the mapping unit 523 converts the second bit string into a plurality of signal points in the second constellation according to the value of the bit group for each bit group of the second number of bits. Map to any one of these signal points.

  When PSK modulation such as BPSK and QPSK, or QAM modulation such as 16QAM and 64QAM is used as the second mapping method, the second modulation symbol indicates, for example, the magnitude of the in-phase component and the imaginary number is orthogonal. It can be represented by a complex number indicating the magnitude of the component. Further, when PAM modulation is used as the second mapping scheme, the second modulation symbol can be represented by a real number. For the second mapping scheme, a uniform constellation may be used, or a non-uniform constellation may be used.

  Based on the bit value used for generating the first modulation symbol, conversion section 525 performs conversion on the second modulation symbol superimposed on the first modulation symbol. Thereby, the conversion unit 525 performs conversion on the second modulation symbol sequence.

Multiplying unit 514, a first multiplying the amplitude coefficient a ₁ for the first modulation symbol of the first modulation symbol sequence. Multiplying unit 524 multiplies the second amplitude coefficient a ₂ for the second modulation symbols of the second modulation symbol sequence that has been converted by the conversion unit 525. Adder 530 superimposes the first modulation symbol multiplied by _first amplitude coefficient a ₁ and the second modulation symbol multiplied by _second amplitude coefficient a ₂ to generate a plurality of superimposed modulation symbols. Is generated.

  The RF unit 540 transmits the generated superimposed modulation symbol sequence as a signal. Specifically, the RF unit 540 generates a radio frequency band signal as a signal corresponding to the superimposed modulation symbol sequence from the superimposed modulation symbol sequence generated by the addition unit 530, and transmits the radio frequency band signal from the antenna. Send.

  That is, the superimposing unit composed of the multiplying unit 514, the multiplying unit 524, and the adding unit 530 superimposes the first modulation symbol sequence and the second modulation symbol sequence with a predetermined amplitude ratio, thereby generating the first data A multiplexed signal that is a signal in which the sequence and the second data sequence are multiplexed is generated. Then, the RF unit 540 transmits a multiplexed signal. The multiplexed signal corresponds to a superimposed modulation symbol sequence. Further, the predetermined amplitude ratio may be 1: 1, and the multiplication process may be omitted.

  The operation of the conversion unit 525 will be described using an example in which QPSK is used as the first mapping method.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 513, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 6.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity (positive or negative) of either one or both of the real part and the imaginary part of Expression 6 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The conversion unit 525 converts the t-th modulation symbol S ₂ (t) of the second modulation symbol sequence generated by the mapping unit 523 into S based on b ₁ (t) and b ₂ (t) as shown in Equation 7. 'Convert to ₂ (t).

Here, S ′ ₂ (t) is the t-th modulation symbol of the converted second modulation symbol string. Re [S ₂ (t)] is the value of the real part of S ₂ (t), and Im [S ₂ (t)] is the value of the imaginary part of S ₂ (t). The modulation symbol S ′ ₂ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 7 is inverted.

  As described above, in the modified superposition coding, the polarities of the real part and the imaginary part of the second modulation symbol depend on the value of the bit mapped to the first modulation symbol superimposed on the second modulation symbol. Be controlled. Note that the polarities of the real part and the imaginary part of the second modulation symbol may be controlled according to the first modulation symbol superimposed on the second modulation symbol. Also, either the real part or the imaginary part of the second modulation symbol may be controlled, or both polarities may be controlled.

  FIG. 14 shows an example of a configuration of a transmission apparatus 600 that multiplexes and transmits two data sequences in two layers using modified superposition coding. The configuration of the transmission device 600 is different from the configuration of the transmission device 500. The configuration and operation of the transmission device 600 will be described with reference to FIG.

  Transmitting apparatus 600 includes encoding section 611, interleaving section 612, mapping section 613, multiplication section 614, encoding section 621, interleaving section 622, mapping section 623, conversion section 625, multiplication section 624, addition section 630 and RF section 640. Is provided. Each component may be a dedicated or general purpose circuit. The multiplication unit 614, the multiplication unit 624, and the addition unit 630 can be expressed as a superposition unit as a whole. The RF unit 640 can also be expressed as a transmission unit. The RF unit 640 may include an antenna.

  The encoding unit 611 performs encoding based on the first error control encoding method on the input first data series to generate a first bit string. The interleaving unit 612 rearranges the bit order of the first bit string generated by the encoding unit 611 based on the first rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 613 performs mapping processing according to the first mapping scheme on the first bit sequence rearranged by the interleaving unit 612, and a first modulation symbol sequence configured by a plurality of first modulation symbols Is generated. In the mapping process according to the first mapping method, the mapping unit 613 converts the first bit string for each bit group of the first number of bits to a plurality of signal points in the first constellation according to the value of the bit group. Map to any one of these signal points.

  The encoding unit 621 performs encoding based on the second error control encoding method on the input second data series to generate a second bit string. The interleaving unit 622 rearranges the bit order of the second bit string generated by the encoding unit 621 based on the second rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 623 performs mapping processing according to the second mapping method on the second bit sequence rearranged by the interleaving unit 622, and a second modulation symbol sequence composed of a plurality of second modulation symbols Is generated. In the mapping process according to the second mapping method, the mapping unit 623 converts the second bit string into a plurality of signal points in the second constellation according to the value of the bit group for each bit group of the second number of bits. Map to any one of these signal points.

  Based on the generated first modulation symbol, conversion section 625 performs conversion on the second modulation symbol superimposed on the first modulation symbol. Thereby, the conversion unit 625 performs conversion on the second modulation symbol sequence.

Multiplier 614, a first multiplying the amplitude coefficient a ₁ for the first modulation symbol of the first modulation symbol sequence. Multiplying unit 624 multiplies the second amplitude coefficient a ₂ for the second modulation symbols of the second modulation symbol sequence that has been converted by the conversion unit 625. Adder 630 superimposes the first modulation symbol multiplied by _first amplitude coefficient a ₁ and the second modulation symbol multiplied by _second amplitude coefficient a ₂ to generate a plurality of superimposed modulation symbols. Is generated.

  The RF unit 640 transmits the generated superimposed modulation symbol sequence as a signal. Specifically, the RF unit 640 generates a radio frequency band signal as a signal corresponding to the superimposed modulation symbol sequence from the superimposed modulation symbol sequence generated by the adding unit 630, and transmits the radio frequency band signal from the antenna. Send.

  That is, the superimposing unit composed of the multiplying unit 614, the multiplying unit 624, and the adding unit 630 superimposes the first modulation symbol sequence and the second modulation symbol sequence with a predetermined amplitude ratio, thereby generating the first data A multiplexed signal that is a signal in which the sequence and the second data sequence are multiplexed is generated. Then, the RF unit 640 transmits a multiplexed signal. The multiplexed signal corresponds to a superimposed modulation symbol sequence. Further, the predetermined amplitude ratio may be 1: 1, and the multiplication process may be omitted.

  Taking the case of using QPSK as the first mapping method as an example, the operation of the converting unit 625 will be described.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 613, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 8.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 8 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The conversion unit 625 converts the t-th modulation symbol S ₂ (t) of the second modulation symbol sequence generated by the mapping unit 623 into S ′ ₂ (t) based on the modulation symbol S ₁ (t) as shown in Equation 9. ).

Here, S ′ ₂ (t) is the t-th modulation symbol of the converted second modulation symbol string. Re [S ₂ (t)] is the value of the real part of S ₂ (t), and Im [S ₂ (t)] is the value of the imaginary part of S ₂ (t). Further, sgn (Re [S ₁ (t)]) is the polarity of the real part of S ₁ (t), and sgn (Im [S ₁ (t)]) is the polarity of the imaginary part of S ₁ (t). is there.

The modulation symbol S ′ ₂ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 9 is inverted. Note that the conversion based on Expression 9 is substantially the same as the conversion based on Expression 7.

  As described above, in the modified superposition coding, the polarities of the real part and the imaginary part of the second modulation symbol are controlled according to the first modulation symbol superimposed on the second modulation symbol. Note that the polarities of the real part and the imaginary part of the second modulation symbol may be controlled according to the value of the bit mapped to the first modulation symbol superimposed on the second modulation symbol. Also, either the real part or the imaginary part of the second modulation symbol may be controlled, or both polarities may be controlled.

  FIG. 15 shows an example of a configuration of a transmission apparatus 700 that multiplexes and transmits two data sequences in two layers using modified superposition coding. The configuration of transmission device 700 is different from the configuration of transmission devices 500 and 600. The configuration and operation of the transmission apparatus 700 will be described with reference to FIG.

  The transmission apparatus 700 includes an encoding unit 711, an interleaving unit 712, a mapping unit 713, a multiplying unit 714, an encoding unit 721, an interleaving unit 722, a mapping unit 723, a multiplying unit 724, an adding unit 730, and an RF unit 740. Each component may be a dedicated or general purpose circuit. The multiplication unit 714, the multiplication unit 724, and the addition unit 730 can be expressed as a superposition unit as a whole. The RF unit 740 can also be expressed as a transmission unit. The RF unit 740 may include an antenna. The mapping unit 723 may include a conversion unit.

  The encoding unit 711 performs encoding based on the first error control encoding scheme on the input first data series to generate a first bit string. The interleaving unit 712 rearranges the bit order of the first bit string generated by the encoding unit 711 based on the first rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 713 performs mapping processing according to the first mapping method on the first bit sequence rearranged by the interleaving unit 712, and the first modulation symbol sequence configured by a plurality of first modulation symbols Is generated. In the mapping process according to the first mapping method, the mapping unit 713 assigns the first bit string to a plurality of signal points in the first constellation according to the value of the bit group for each bit group of the first number of bits. Map to any one of these signal points.

  The encoding unit 721 performs encoding based on the second error control encoding scheme on the input second data series to generate a second bit string. The interleaving unit 722 rearranges the bit order of the second bit string generated by the encoding unit 721 based on the second rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 723 converts (modifies) the second mapping method according to the first bit string mapped to the first modulation symbol string by the mapping unit 713. Then, the mapping unit 723 performs mapping processing according to the second mapping method converted according to the first bit string, on the second bit string rearranged by the interleaving unit 722. As a result, the mapping unit 723 generates a second modulation symbol string including a plurality of second modulation symbols.

  In the mapping process according to the second mapping method, the mapping unit 723 sets the second bit string for each bit group having the second number of bits according to the value of the bit group and the plurality of signal points in the second constellation. Map to any one of these signal points.

Multiplying unit 714, a first multiplying the amplitude coefficient a ₁ for the first modulation symbol of the first modulation symbol sequence. Multiplying unit 724, second multiplying the amplitude coefficient a ₂ for the second modulation symbols of the second modulation symbol sequence. Addition unit 730, a first modulation symbol, the second amplitude coefficient a ₂ is superimposed and the second modulation symbols multiplied, a plurality of superimposed modulation symbols first amplitude coefficient a ₁ is multiplied Is generated.

  The RF unit 740 transmits the generated superimposed modulation symbol sequence as a signal. Specifically, the RF unit 740 generates a radio frequency band signal as a signal corresponding to the superimposed modulation symbol sequence from the superimposed modulation symbol sequence generated by the adding unit 730, and transmits the radio frequency band signal from the antenna. Send.

  That is, the superimposing unit composed of the multiplying unit 714, the multiplying unit 724, and the adding unit 730 superimposes the first modulation symbol sequence and the second modulation symbol sequence with a predetermined amplitude ratio, thereby generating the first data A multiplexed signal that is a signal in which the sequence and the second data sequence are multiplexed is generated. Then, the RF unit 740 transmits a multiplexed signal. The multiplexed signal corresponds to a superimposed modulation symbol sequence. Further, the predetermined amplitude ratio may be 1: 1, and the multiplication process may be omitted.

  Taking the case of using QPSK as the first mapping method as an example, the operation of the mapping unit 723 will be described.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 713, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 10.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 10 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The mapping unit 723 performs an exclusive OR of b ₁ (t) on the bits most contributing to the real part of the second constellation in the second bit string input from the interleaving unit 722. Also, the mapping unit 723 performs an exclusive OR of b ₂ (t) on the bit that contributes most to the imaginary part of the second constellation in the second bit string input from the interleaving unit 722. . Then, the second bit string subjected to these exclusive OR is mapped based on the second constellation.

  Here, the bit that contributes most to the real part of the second constellation is, for example, that the polarity of the real part of the second constellation is inverted when the value of the bit is inverted from 0 to 1 or from 1 to 0. Means a bit. That is, the bit that contributes most to the real part of the second constellation is, for example, when the value of the bit is inverted from 0 to 1 or from 1 to 0, the sign of the value of the real part in the modulation symbol is inverted. Means a bit.

  Similarly, the bit that contributes most to the imaginary part of the second constellation is, for example, that the polarity of the imaginary part of the second constellation is inverted when the value of the bit is inverted from 0 to 1 or from 1 to 0. Means a bit. That is, the bit that contributes most to the imaginary part of the second constellation is, for example, when the value of the bit is inverted from 0 to 1 or from 1 to 0, the sign of the value of the imaginary part in the modulation symbol is inverted. Means a bit.

  In the above description, the mapping unit 723 substantially converts the second mapping method (second constellation) by converting the second bit string. However, the mapping unit 723 may directly convert the second mapping method (second constellation) without converting the second bit string. That is, the mapping unit 723 may convert the association between the bit group and the signal point in the second constellation.

  Further, the conversion performed by the mapping unit 723 may be performed by a conversion unit included in the mapping unit 723.

  As described above, in the modified superposition coding, the polarities of the real part and the imaginary part of the second modulation symbol depend on the value of the bit mapped to the first modulation symbol superimposed on the second modulation symbol. Be controlled. Note that the polarities of the real part and the imaginary part of the second modulation symbol may be controlled according to the first modulation symbol superimposed on the second modulation symbol. Also, either the real part or the imaginary part of the second modulation symbol may be controlled, or both polarities may be controlled.

<Sequential decoding of signals obtained by modified superposition coding>
FIG. 16 receives a signal in which two data sequences are multiplexed in two layers using the above-described modified superposition coding and sequentially decodes to acquire both or one of the two multiplexed data sequences. 2 shows an example of a configuration of a receiving device 800 that can be used. The configuration and operation of receiving apparatus 800 will be described with reference to FIG.

  The receiving apparatus 800 includes an RF unit 830, a demapping unit 811, a deinterleaving unit 812, a decoding unit 813, an encoding unit 814, an interleaving unit 815, a mapping unit 816, a multiplication unit 817, a delay unit 818, a subtraction unit 819, and a conversion unit. 820, a demapping unit 821, a deinterleaving unit 822, and a decoding unit 823. Each component may be a dedicated or general purpose circuit.

  Demapping unit 811, deinterleaving unit 812, decoding unit 813, encoding unit 814, interleaving unit 815, mapping unit 816, multiplication unit 817, delay unit 818, subtraction unit 819, conversion unit 820, demapping unit 821, deinterleaving The unit 822 and the decoding unit 823 can also be expressed as a derivation unit as a whole. The RF unit 830 can also be expressed as a receiving unit. The RF unit 830 may include an antenna.

  The receiving device 800 receives the multiplexed signal transmitted from the transmitting device 500, 600, or 700 with an antenna and inputs it to the RF unit 830. That is, the RF unit 830 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 830 is also expressed as a received signal, and corresponds to the superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 830 generates a baseband reception signal from the reception signal in the radio frequency band.

The demapping unit 811 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. For example, a first constellation for demapping the amplitude coefficients a ₁ are reflected.

  The deinterleaving unit 812 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 813 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence rearranged by deinterleaving section 812, and outputs the decoding result as a first data sequence. .

  Here, the demapping unit 811 treats a component corresponding to the second modulation symbol of the second data series as an unknown signal (noise) in the received signal corresponding to the superimposed modulation symbol sequence, and performs the first mapping Demapping is performed based on the first constellation of the scheme.

  When only the first data series is an acquisition target, the receiving apparatus 800 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, receiving apparatus 800 acquires the second data series. Therefore, the following processing is performed.

  The encoding unit 814 performs encoding based on the first error control encoding method on the first data series acquired by the decoding unit 813 to generate a first bit string. The interleaving unit 815 rearranges the bit order of the first bit string generated by the encoding unit 814 based on the first rearrangement rule. This rearrangement is also called interleaving.

The mapping unit 816 performs mapping processing according to the first mapping method on the first bit sequence rearranged by the interleaving unit 815, and the first modulation symbol sequence configured by a plurality of first modulation symbols Is generated. Multiplying unit 817 multiplies the first amplitude coefficient a ₁ in the first modulation symbol sequence mapping unit 816 outputs.

  The delay unit 818 outputs the reception signal output from the RF unit 830 from when the RF unit 830 outputs the baseband reception signal to when the multiplier 817 outputs the reproduced first modulation symbol sequence. Delay.

The subtraction unit 819 subtracts the first modulation symbol sequence multiplied by the _first amplitude coefficient a ₁ by the multiplication unit 817 from the reception signal delayed by the delay unit 818. Thereby, the subtracting unit 819 removes the component corresponding to the first modulation symbol from the reception signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 819 outputs a signal in which a component corresponding to the second modulation symbol and noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The conversion unit 820 converts the signal output from the subtraction unit 819 as a signal corresponding to the second modulation symbol sequence using the first bit sequence reproduced by encoding and interleaving. The demapping unit 821 demaps the signal output from the conversion unit 820 based on the second constellation of the second mapping scheme, and generates a second bit likelihood sequence. For example, the amplitude coefficient a ₂ is reflected in the second constellation for demapping.

  The deinterleaving unit 822 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 823 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 822, and outputs the decoding result as a second data sequence. .

  Taking the case of using QPSK as the first mapping method as an example, the operation of the conversion unit 820 will be described.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 816, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 11.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 11 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The conversion unit 820 converts the signal S ₂ (t) corresponding to the t-th modulation symbol of the second modulation symbol sequence out of the signals output from the subtraction unit 819 into b ₁ (t) and b ₂ as shown in Expression 12. Conversion to S ′ ₂ (t) based on (t).

Here, S ′ ₂ (t) is a signal after conversion. Re [S ₂ (t)] is the value of the real part of S ₂ (t), and Im [S ₂ (t)] is the value of the imaginary part of S ₂ (t). The converted signal S ′ ₂ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 12 is inverted.

  As described above, receiving apparatus 800 acquires both or one of the first data series and the second data series from the signal received by the antenna.

  FIG. 17 shows the reception of a signal in which two data sequences are multiplexed in two layers using the above-described modified superposition coding, and sequentially decodes to acquire both or one of the two multiplexed data sequences. 2 shows an example of a configuration of a receiving device 900 that can be used. The configuration of receiving apparatus 900 is different from the configuration of receiving apparatus 800. The configuration and operation of the receiving apparatus 900 will be described with reference to FIG.

  Receiving apparatus 900 includes RF section 930, demapping section 911, deinterleaving section 912, decoding section 913, encoding section 914, interleaving section 915, mapping section 916, multiplication section 917, delay section 918, subtraction section 919, and conversion section. 920, a demapping unit 921, a deinterleaving unit 922, and a decoding unit 923. Each component may be a dedicated or general purpose circuit.

  Demapping unit 911, deinterleaving unit 912, decoding unit 913, encoding unit 914, interleaving unit 915, mapping unit 916, multiplication unit 917, delay unit 918, subtraction unit 919, conversion unit 920, demapping unit 921, deinterleaving Unit 922 and decoding unit 923 can also be expressed as a derivation unit as a whole. The RF unit 930 can also be expressed as a receiving unit. The RF unit 930 may include an antenna.

  The receiving device 900 receives the multiplexed signal transmitted from the transmitting device 500, 600, or 700 with an antenna and inputs it to the RF unit 930. That is, the RF unit 930 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 930 is also expressed as a received signal, and corresponds to the superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 930 generates a baseband reception signal from the reception signal in the radio frequency band.

The demapping unit 911 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. For example, a first constellation for demapping the amplitude coefficients a ₁ are reflected.

  The deinterleaving unit 912 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. The decoding unit 913 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence rearranged by the deinterleaving unit 912, and outputs the decoding result as a first data sequence. .

  Here, the demapping unit 911 treats a component corresponding to the second modulation symbol of the second data series as an unknown signal (noise) in the received signal corresponding to the superimposed modulation symbol sequence, and performs the first mapping Demapping is performed based on the first constellation of the scheme.

  When only the first data series is an acquisition target, the receiving device 900 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, receiving apparatus 900 acquires the second data series. Therefore, the following processing is performed.

  The encoding unit 914 performs encoding based on the first error control encoding method on the first data series acquired by the decoding unit 913 to generate a first bit string. The interleaving unit 915 rearranges the bit order of the first bit string generated by the encoding unit 914 based on the first rearrangement rule. This rearrangement is also called interleaving.

The mapping unit 916 performs mapping processing according to the first mapping method on the first bit sequence rearranged by the interleaving unit 915, and a first modulation symbol sequence configured by a plurality of first modulation symbols Is generated. Multiplying unit 917 multiplies the first amplitude coefficient a ₁ in the first modulation symbol sequence mapping unit 916 outputs.

  The delay unit 918 outputs the reception signal output from the RF unit 930 from when the RF unit 930 outputs the baseband reception signal until the multiplication unit 917 outputs the reproduced first modulation symbol sequence. Delay.

The subtraction unit 919 subtracts the first modulation symbol string multiplied by the _first amplitude coefficient a ₁ by the multiplication unit 917 from the reception signal delayed by the delay unit 918. As a result, the subtraction unit 919 removes the component corresponding to the first modulation symbol from the reception signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 919 outputs a signal in which a component corresponding to the second modulation symbol and noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The conversion unit 920 converts the signal output from the subtraction unit 919 as a signal corresponding to the second modulation symbol sequence, using the first modulation symbol sequence reproduced by encoding, interleaving, mapping, and the like. The demapping unit 921 demaps the signal output from the conversion unit 920 based on the second constellation of the second mapping scheme, and generates a second bit likelihood sequence. For example, the amplitude coefficient a ₂ is reflected in the second constellation for demapping.

  The deinterleaving unit 922 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 923 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 922, and outputs the decoding result as a second data sequence .

  Taking the case of using QPSK as the first mapping method as an example, the operation of the conversion unit 920 will be described.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 916, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 13.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 13 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The conversion unit 920 converts the signal S ₂ (t) corresponding to the t-th modulation symbol of the second modulation symbol sequence out of the signals output from the subtraction unit 919 into the modulation symbol S ₁ (t) as shown in Equation 14. On the basis of S ′ ₂ (t).

Here, S ′ ₂ (t) is a signal after conversion. Re [S ₂ (t)] is the value of the real part of S ₂ (t), and Im [S ₂ (t)] is the value of the imaginary part of S ₂ (t). Further, sgn (Re [S ₁ (t)]) is the polarity of the real part of S ₁ (t), and sgn (Im [S ₁ (t)]) is the polarity of the imaginary part of S ₁ (t). is there. The converted signal S ′ ₂ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 14 is inverted. Note that the conversion based on Expression 14 is substantially the same as the conversion based on Expression 12.

  As described above, receiving apparatus 900 acquires both or one of the first data series and the second data series from the signal received by the antenna.

  FIG. 18 shows the reception of a signal in which two data sequences are multiplexed in two layers using the above-described modified superposition coding, and sequentially decodes and acquires both or one of the two multiplexed data sequences. 2 shows an example of a configuration of a receiving apparatus 1000 that can be used. The configuration of receiving apparatus 1000 is different from the configuration of receiving apparatuses 800 and 900. The configuration and operation of the receiving apparatus 1000 will be described with reference to FIG.

  The receiving apparatus 1000 includes an RF unit 1030, a demapping unit 1011, a deinterleaving unit 1012, a decoding unit 1013, an encoding unit 1014, an interleaving unit 1015, a mapping unit 1016, a multiplication unit 1017, a delay unit 1018, a subtraction unit 1019, and a demapping. Unit 1021, deinterleave unit 1022, and decoding unit 1023. Each component may be a dedicated or general purpose circuit.

  Demapping unit 1011, Deinterleaving unit 1012, Decoding unit 1013, Encoding unit 1014, Interleaving unit 1015, Mapping unit 1016, Multiplying unit 1017, Delay unit 1018, Subtracting unit 1019, Demapping unit 1021, Deinterleaving unit 1022 and Decoding The unit 1023 can also be expressed as a derivation unit as a whole. The RF unit 1030 can also be expressed as a receiving unit. The RF unit 1030 may include an antenna. The demapping unit 1021 may include a conversion unit.

  The receiving apparatus 1000 receives the multiplexed signal transmitted from the transmitting apparatus 500, 600, or 700 with an antenna and inputs it to the RF unit 1030. That is, the RF unit 1030 receives multiple signals via the antenna. The multiplexed signal received by the RF unit 1030 is also expressed as a received signal, and corresponds to a superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 1030 generates a baseband received signal from a received signal in the radio frequency band.

The demapping unit 1011 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. For example, a first constellation for demapping the amplitude coefficients a ₁ are reflected.

  The deinterleaving unit 1012 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 1013 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence rearranged by deinterleaving section 1012, and outputs the decoding result as a first data sequence. .

  Here, the demapping unit 1011 treats the component corresponding to the second modulation symbol of the second data series in the received signal corresponding to the superimposed modulation symbol sequence as an unknown signal (noise), and performs the first mapping scheme. Demapping is performed based on the first constellation.

  When only the first data series is the acquisition target, the receiving apparatus 1000 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, receiving apparatus 1000 acquires the second data series. Therefore, the following processing is performed.

  The encoding unit 1014 performs encoding based on the first error control encoding method on the first data series acquired by the decoding unit 1013 to generate a first bit string. The interleaving unit 1015 rearranges the bit order of the first bit string generated by the encoding unit 1014 based on the first rearrangement rule. This rearrangement is also called interleaving.

The mapping unit 1016 performs a mapping process according to the first mapping method on the first bit sequence rearranged by the interleaving unit 1015, and a first modulation symbol sequence composed of a plurality of first modulation symbols Is generated. Multiplying unit 1017 multiplies the first amplitude coefficient _{a 1} in the first modulation symbol sequence mapping unit 1016 outputs.

  The delay unit 1018 outputs the received signal output from the RF unit 1030 from when the RF unit 1030 outputs the baseband received signal until the multiplier 1017 outputs the reproduced first modulation symbol sequence. Delay.

The subtracting unit 1019 subtracts the first modulation symbol string multiplied by the _first amplitude coefficient a ₁ by the multiplying unit 1017 from the reception signal delayed by the delay unit 1018. Thereby, the subtraction unit 1019 removes the component corresponding to the first modulation symbol from the reception signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 1019 outputs a signal in which the component corresponding to the second modulation symbol and the noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The demapping unit 1021 demaps the signal output from the subtraction unit 1019 as a signal corresponding to the second modulation symbol sequence based on the second constellation of the second mapping scheme, and the second bit likelihood Generate a column. At this time, the first bit string reproduced by encoding and interleaving is reflected in this process. Further, for example, in the second constellation for demapping, the amplitude coefficient a ₂ is reflected.

  The deinterleaving unit 1022 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 1023 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 1022, and outputs the decoding result as a second data sequence .

  The operation of the demapping unit 1021 will be described using an example in which QPSK is used as the first mapping method.

For example, S ₁ (t) is the t-th modulation symbol of the first modulation symbol sequence generated by the mapping unit 1016, and b ₁ (t) and b ₂ (t) are changed to S ₁ (t). If there are multiple bits to be mapped, the modulation symbol S ₁ (t) is given by Equation 15.

Here, i is an imaginary unit. The modulation symbol S ₁ (t) may be given by an expression in which the polarity of one or both of the real part and the imaginary part of Expression 15 is inverted. Bit b ₁ (t) is a bit contributing to the real part of modulation symbol S ₁ (t). Bit b ₂ (t) is a bit contributing to the imaginary part of modulation symbol S ₁ (t).

The demapping unit 1021 uses the signal S ₂ (t) output from the subtraction unit 1019 as a signal corresponding to the t-th modulation symbol of the second modulation symbol sequence based on the second constellation of the second mapping scheme. And then demapping.

The demapping unit 1021 inverts the bit likelihood corresponding to the bit most contributing to the real part of the second constellation in the bit likelihood sequence obtained by demapping according to b ₁ (t). Apply processing. Also, the demapping unit 1021 responds to b ₂ (t) for the bit likelihood corresponding to the bit most contributing to the imaginary part of the second constellation in the bit likelihood sequence obtained by demapping. Apply reverse processing.

For example, the demapping unit 1021 excludes b ₁ (t) for the bit likelihood corresponding to the bit most contributing to the real part of the second constellation in the bit likelihood sequence obtained by demapping. Perform logical OR. Further, the demapping unit 1021 excludes b ₂ (t) from the bit likelihood corresponding to the bit most contributing to the imaginary part of the second constellation in the bit likelihood sequence obtained by demapping. Perform logical OR.

  The demapping unit 1021 outputs the bit likelihood sequence after the above inversion processing as a second bit likelihood sequence.

  In the above, the demapping unit 1021 substantially converts the second mapping scheme (second constellation) by converting the bit likelihood sequence. However, the demapping unit 1021 may directly convert the second mapping method (second constellation) without converting the bit likelihood sequence. That is, the demapping unit 1021 may convert the association between the bit group and the signal point in the second constellation.

  Further, the conversion performed by the demapping unit 1021 may be performed by a conversion unit included in the demapping unit 1021.

  As described above, receiving apparatus 1000 acquires both or one of the first data series and the second data series from the signal received by the antenna.

<Parallel decoding of signals obtained by modified superposition coding>
Hereinafter, a reception method for parallel decoding of signals obtained by modified superposition coding according to the present embodiment will be described. The configuration of the transmission apparatus is the same as that of the transmission apparatus 500 shown in FIG. 13, the transmission apparatus 600 shown in FIG. 14, or the transmission apparatus 700 shown in FIG. In the parallel decoding in the modified superposition coding, the reception apparatus removes the component of the first layer modulation symbol sequence from the unknown signal (noise) without removing the component of the first layer modulation symbol sequence included in the received signal. ) And decrypt the second layer.

  FIG. 19 shows a case where a signal in which two data sequences are multiplexed in two layers is received and decoded in parallel using modified superposition coding to obtain both or one of the two multiplexed data sequences. An example of a configuration of a possible receiving device 1100 is shown. The configuration and operation of the receiving apparatus 1100 will be described with reference to FIG.

  The receiving device 1100 includes an RF unit 1130, a demapping unit 1110, a deinterleaving unit 1112, a decoding unit 1113, a deinterleaving unit 1122, and a decoding unit 1123. Each component may be a dedicated or general purpose circuit. The demapping unit 1110, the deinterleaving unit 1112, the decoding unit 1113, the deinterleaving unit 1122, and the decoding unit 1123 can be expressed as a derivation unit as a whole. The RF unit 1130 can also be expressed as a receiving unit. The RF unit 1130 may include an antenna.

  The receiving apparatus 1100 receives the multiplexed signal transmitted from the transmitting apparatus 500, 600, or 700 with an antenna and inputs it to the RF unit 1130. That is, the RF unit 1130 receives a multiplexed signal via the antenna. The multiplexed signal received by the RF unit 1130 can also be expressed as a received signal. The RF unit 1130 generates a baseband received signal from the received signal in the radio frequency band.

  The demapping unit 1110 demaps the baseband received signal and generates a first bit likelihood sequence and a second bit likelihood sequence. For example, the demapping unit 1110 performs demapping based on a modified superposition constellation that indicates the arrangement of signal points of the superimposed modulation symbol in which the first modulation symbol and the second modulation symbol are superimposed using modified superposition coding. I do.

Variations superimposed constellation is determined according to the first constellation of the first mapping scheme, a second constellation of a second mapping scheme, the first amplitude coefficient a ₁ and the first amplitude coefficient a _2, etc. .

  FIG. 20 shows an example of a modified superimposed constellation corresponding to modified superimposed coding. Specifically, the QPSK constellation shown in FIG. 4 and the Nu-256QAM constellation shown in FIG. 5 are combined.

  More specifically, Nu-256QAM constellations (256 signal points) are arranged in each of the four regions on the complex plane in accordance with the four signal points of the QPSK constellation. These four regions corresponding to the Nu-256QAM constellation may partially overlap. In this modified superimposed constellation, the conversion of the second modulation symbol sequence is reflected.

  For example, when the constellation of Nu-256QAM is combined with the signal point whose real part is positive among the four signal points of the constellation of QPSK, the polarity of the real part of the constellation of Nu-256QAM is Inverted. Further, for example, when the Nu-256QAM constellation is combined with the signal point having the positive imaginary part among the four signal points of the QPSK constellation, the imaginary part of the Nu-256QAM constellation is combined. The polarity is reversed.

  Specifically, FIG. 20 shows a first signal point, a second signal point, a third signal point, a fourth signal point, a fifth signal point, and a sixth signal point. When the polarity of the real part of the constellation of Nu-256QAM is not inverted, the first signal point and the third signal point correspond to the same bit value for the second bit string. Similarly, when the polarity of the imaginary part of the constellation of Nu-256QAM is not inverted, the fourth signal point and the sixth signal point correspond to the same bit value for the second bit string.

  When the polarity of the real part of the constellation of Nu-256QAM is inverted, the first signal point and the second signal point correspond to the same bit value for the second bit string. In addition, when the polarity of the imaginary part of the constellation of Nu-256QAM is inverted, the fourth signal point and the fifth signal point correspond to the same bit value for the second bit string. That is, a plurality of signal points corresponding to the same bit value for the second bit string are brought closer to each other by inversion and are collected. Thereby, the influence exerted on demapping by noise is suppressed.

  The demapping unit 1110 performs demapping based on a modified superposition constellation as shown in FIG. That is, demapping section 1110 generates a first bit likelihood sequence in a state where the modulation symbol sequence of the second layer is unknown, and generates a second bit likelihood in a state where the modulation symbol sequence of the first layer is unknown. Generate a degree sequence.

  Note that the demapping unit 1110 uses the first constellation of the first mapping scheme for generating the first bit likelihood sequence, and for generating the second bit likelihood sequence, the modified superimposed constellation described above. May be used.

  When the first constellation is used to generate the first bit likelihood sequence, the demapping unit 1110 is more efficient than the case where the modified superposition constellation is also used to generate the first bit likelihood sequence. It is possible to reduce the number of signal points considered for generating one bit likelihood sequence. Therefore, in this case, the demapping unit 1110 can reduce the calculation amount.

  Further, for example, the demapping unit 1110 includes a first demapping unit that generates a first bit likelihood sequence by demapping the received signal, and a second bit likelihood by demapping the received signal. This corresponds to the second demapping unit that generates a column. The demapping unit 1110 generates a first bit likelihood sequence by demapping the received signal and a second bit likelihood sequence by demapping the received signal. And a second demapping unit.

  Further, the demapping unit 1110 may convert the second bit likelihood sequence generated by the superposition constellation instead of the modified superposition constellation according to the first bit likelihood sequence. Thereby, the demapping unit 1110 can acquire the same second bit likelihood sequence as the second bit likelihood sequence generated by the modified superposition constellation.

  Further, the demapping unit 1110 converts the multiplexed signal without using the modified superimposition constellation, thereby obtaining the same second bit likelihood sequence as the second bit likelihood sequence generated by the modified superimposition constellation. You may get it.

  The deinterleaving unit 1112 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 1113 performs decoding processing based on the first error control coding scheme on the first bit likelihood sequence rearranged by deinterleaving section 1112 and outputs the decoding result as a first data sequence. .

  The deinterleaving unit 1122 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving. Decoding section 1123 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 1122, and outputs the decoding result as a second data sequence .

  As described above, receiving apparatus 1100 acquires both or one of the first data series and the second data series from the signal received by the antenna.

  In transmitting apparatuses 500, 600 and 700 and receiving apparatuses 800, 900, 1000 and 1100, rearrangement (interleaving and deinterleaving) may be omitted as in the first embodiment. That is, each interleaving unit and each deinterleaving unit are arbitrary components, and may not be included in these devices.

  However, interleaving and deinterleaving constitute a pair. Therefore, basically, when transmitting apparatuses 500, 600, and 700 include each interleaving section, receiving apparatuses 800, 900, 1000, and 1100 include each deinterleaving section and each interleaving section. On the other hand, when transmitting apparatuses 500, 600, and 700 do not include each interleave unit, receiving apparatuses 800, 900, 1000, and 1100 do not include each deinterleave unit and each interleave unit.

In the receiving device 800, 900 and 1000, the amplitude coefficients _{a 1} to a mapping for generating a first modulation symbol may be reflected. In this case, multiplication of the amplitude coefficients a ₁ may be omitted. The receiving apparatuses 800, 900, and 1000 may not include the multiplying units 817, 917, and 1017, respectively.

  Further, the error control encoding of the first data series and the second data series may be performed by an external device. In this case, error control coding may be omitted in transmitting apparatuses 500, 600, and 700. The transmission apparatuses 500, 600, and 700 may not include the encoding units 511, 521, 611, 621, 711, and 721.

  FIG. 21 is a flowchart illustrating an operation example of the transmission apparatus 500. First, the mapping unit 513 generates a first modulation symbol string of the first data series by mapping the first bit string of the first data series (S301). Then, the mapping unit 523 generates the second modulation symbol string of the second data sequence by mapping the second bit string of the second data sequence (S302).

  The conversion unit 525 provides conversion corresponding to the first modulation symbol sequence to the second modulation symbol sequence (S303). Specifically, the conversion unit 525 converts the second modulation symbol sequence into the second modulation symbol sequence by converting the second modulation symbol sequence according to the first bit sequence.

  Next, the superimposing unit composed of the first multiplying unit 514, the second multiplying unit 524, and the adding unit 530 provides conversion according to the first modulation symbol sequence and the first modulation symbol sequence. A multiplexed signal is generated by superimposing the modulated second modulation symbol sequence at a predetermined amplitude ratio (S304). Then, the RF unit 540 transmits the generated multiplexed signal (S305).

  In the above operation example, transmitting apparatus 500 converts the second modulation symbol sequence by converting the second modulation symbol sequence by converting the second modulation symbol sequence according to the first bit sequence. (S303). Instead, by converting the second modulation symbol sequence according to the first modulation symbol sequence as in the transmission apparatus 600, the conversion according to the first modulation symbol sequence is converted to the second modulation symbol sequence. May be brought to the queue.

  Alternatively, even when the second bit string or the second mapping scheme (second constellation) for generating the second modulation symbol string is converted according to the first bit string, as in the transmitting apparatus 700. Good. Thereby, a conversion corresponding to the first modulation symbol sequence may be provided to the second modulation symbol sequence. In this case, the second bit string or the second mapping scheme is converted before generating the second modulation symbol string.

  That is, conversion according to the first modulation symbol sequence is performed by converting the second bit sequence, the second mapping scheme, or the second modulation symbol sequence according to the first bit sequence or the first modulation symbol sequence. May be provided in the second modulation symbol sequence.

  Also, the conversion unit 525 controls the polarity of the real part and the imaginary part of each modulation symbol in the second modulation symbol sequence by bringing the second modulation symbol sequence into conversion according to the first modulation symbol sequence. May be. Thereby, conversion section 525 inverts the polarity of the real part of the second modulation symbol when the real part of the first modulation symbol satisfies the predetermined real part condition, and the imaginary part of the first modulation symbol is predetermined. When the above condition is satisfied, the polarity of the imaginary part of the second modulation symbol may be inverted.

  The predetermined real part condition may be a condition that the polarity of the real part is a predetermined real part polarity, or a condition that the real part is within a predetermined range of one or more real parts. The predetermined one or more real part ranges may be positive ranges or negative ranges. Similarly, the predetermined imaginary part condition may be a condition that the polarity of the imaginary part is a predetermined imaginary part polarity, or may be a condition that the imaginary part is within a predetermined range of one or more imaginary parts. The predetermined one or more imaginary part ranges may be positive ranges or negative ranges.

  FIG. 22 is a flowchart illustrating an operation example of the reception devices 800, 900, 1000, and 1100. First, the receiving unit receives a multiplexed signal (S401). Here, the receiving unit is the RF unit 830 of the receiving device 800, the RF unit 930 of the receiving device 900, the RF unit 1030 of the receiving device 1000, or the RF unit 1130 of the receiving device 1100.

  The multiplexed signal is a signal obtained by multiplexing a plurality of data sequences including the first data sequence of the first hierarchy and the second data sequence of the second hierarchy. The multiplexed signal is a signal in which the first modulation symbol sequence and the second modulation symbol sequence are superimposed at a predetermined amplitude ratio.

  The first modulation symbol string is a modulation symbol string generated by mapping the first bit string of the first data series. The second modulation symbol sequence is a modulation symbol sequence that is generated by mapping the second bit sequence of the second data sequence and has undergone conversion according to the first modulation symbol sequence.

  Next, the deriving unit derives at least one of the first data series and the second data series from the multiplexed signal (S402).

  For example, the deriving unit of the receiving apparatus 800 includes a demapping unit 811, a deinterleaving unit 812, a decoding unit 813, an encoding unit 814, an interleaving unit 815, a mapping unit 816, a multiplying unit 817, a delay unit 818, a subtracting unit 819, a conversion unit Section 820, demapping section 821, deinterleave section 822, and decoding section 823.

  For example, the deriving unit of the receiving device 900 includes a demapping unit 911, a deinterleaving unit 912, a decoding unit 913, an encoding unit 914, an interleaving unit 915, a mapping unit 916, a multiplying unit 917, a delay unit 918, and a subtracting unit 919. A conversion unit 920, a demapping unit 921, a deinterleave unit 922, and a decoding unit 923.

  For example, the deriving unit of the receiving apparatus 1000 includes a demapping unit 1011, a deinterleaving unit 1012, a decoding unit 1013, an encoding unit 1014, an interleaving unit 1015, a mapping unit 1016, a multiplying unit 1017, a delay unit 1018, and a subtracting unit 1019. , A demapping unit 1021, a deinterleaving unit 1022, and a decoding unit 1023.

  Further, for example, the deriving unit of the receiving apparatus 1100 includes a demapping unit 1110, a deinterleaving unit 1112, a decoding unit 1113, a deinterleaving unit 1122, and a decoding unit 1123.

  In accordance with the above operation, a multiplexed signal in which the first modulation symbol sequence and the second modulation symbol sequence obtained by conversion according to the first modulation symbol sequence are superimposed is received. Then, at least one of the first data series and the second data series is derived from the multiplexed signal from the multiplexed signal. That is, a multiplexed signal superimposed so as to reduce performance degradation at the time of parallel decoding is received, and either or either one of the first data sequence and the second data sequence is efficiently derived from the multiplexed signal. It is possible.

  In the receiving apparatus 1100 that performs parallel decoding illustrated in FIG. 19, the decoding performance for the second layer is degraded as compared with the receiving apparatuses 800, 900, and 1000 that perform sequential decoding illustrated in FIGS. 16, 17, and 18.

The figure shows an example of the simulation result of the transmission capacity of the second layer when the ratio of the signal power P _s1 of the first layer and the signal power P _s2 of the second layer is P _s1 : P _s2 = 2: 1. 23. 23, the abscissa represents the signal power _{P s} to noise power _{P n} ratio (SNR) in dB (decibels), the vertical axis represents the transmission capacity. In FIG. 23, the solid line indicates the transmission capacity of the second layer when performing sequential decoding, and the broken line indicates the transmission capacity of the second layer when performing parallel decoding.

  As shown in FIG. 23, when parallel decoding is performed, the SNR required for the same transmission capacity is increased in the second layer decoding as compared with the case of performing sequential decoding, and the same SNR is obtained. Transmission capacity decreases.

  As described above, receiving apparatus 1100 that performs parallel decoding in the present embodiment, compared with receiving apparatuses 800, 900, and 1000 that perform sequential decoding, decodes the second data sequence transmitted in the second layer. Performance is degraded. However, it is possible to reduce the configuration necessary for the decoding of the second hierarchy.

  Specifically, in receiving apparatus 1100, compared with receiving apparatuses 800, 900, and 1000 that perform sequential decoding shown in FIGS. 16, 17, and 18, components for reproducing a modulation symbol string of the first layer Is no longer necessary. That is, the encoding units 814, 914 and 1014, the interleaving units 815, 915 and 1015, the mapping units 816, 916 and 1016, and the multiplication units 817, 917 and 1017 are not necessary.

  Also, the delay units 818, 918 and 1018 for delaying the received signal and the subtracting units 819, 919 and 1019 for removing the first-level modulation symbol component reproduced from the received signal are not necessary.

  Therefore, the circuit scale can be reduced. In addition, the reception device 1100 can reduce the amount of calculation compared to the reception devices 800, 900, and 1000, and can reduce power consumption.

  Furthermore, receiving apparatuses 800, 900, and 1000 that perform sequential decoding shown in FIGS. 16, 17, and 18 demodulate the first layer of the received signal to acquire the first data series, A first modulation symbol sequence is generated from the data series. After that, receiving apparatuses 800, 900, and 1000 start demodulation of the second layer of the received signal and acquire the second data series.

  On the other hand, receiving apparatus 1100 that performs parallel decoding according to the present embodiment can simultaneously acquire the first data series and the second data series in parallel, thereby reducing processing delay. Can do.

  Further, the reception apparatus may observe the SNR of the received signal, and switch the decoding process so that parallel decoding is performed when the SNR is high, and sequential decoding is performed when the SNR is low.

  In this case, for example, the receiving apparatus 800 illustrated in FIG. 16 includes a control unit that switches between sequential decoding and parallel decoding according to the SNR. The control unit may be included in the RF unit 830 or the demapping unit 821. Furthermore, the demapping unit 821 has a configuration for performing the operation of the demapping process based on the modified superimposing constellation described as the operation of the demapping unit 1110 of FIG. 19 in addition to the demapping process based on the second constellation. .

  Then, the demapping unit 821 switches between the demapping process based on the second constellation for the signal output from the conversion unit 820 and the demapping process based on the modified superposition constellation for the signal output from the RF unit 830. . For example, the demapping unit 821 switches between these demapping processes in accordance with a control signal from the control unit.

  Such a configuration includes the receiving device 400 shown in FIG. 11, the receiving device 800 shown in FIG. 16 (the conversion unit 820, the demapping unit 821, etc.), and the receiving device 1100 shown in FIG. ) And in combination.

  As another configuration, for example, the receiving apparatus 900 illustrated in FIG. 17 includes a control unit that switches between sequential decoding and parallel decoding according to the SNR. The control unit may be included in the RF unit 930 or the demapping unit 921. Further, in addition to the demapping process based on the first bit string and the second constellation, the demapping unit 921 performs the demapping process based on the modified superimposing constellation described as the operation of the demapping unit 1110 in FIG. A configuration for performing the operation is provided.

  Then, the demapping unit 921 switches between demapping processing based on the second constellation for the signal output from the conversion unit 920 and demapping processing based on the modified superposition constellation for the signal output from the RF unit 930. . For example, the demapping unit 921 switches these demapping processes according to a control signal from the control unit.

  Such a configuration includes the receiving device 400 shown in FIG. 11, the receiving device 900 shown in FIG. 17 (the conversion unit 920, the demapping unit 921, etc.), and the receiving device 1100 shown in FIG. ) And in combination.

  As another configuration, for example, the receiving apparatus 1000 illustrated in FIG. 18 includes a control unit that switches between sequential decoding and parallel decoding according to the SNR. The control unit may be included in the RF unit 1030 or the demapping unit 1021. Further, in addition to the demapping process based on the first bit string and the second constellation, the demapping unit 1021 performs the demapping process based on the modified superimposing constellation described as the operation of the demapping unit 1110 in FIG. A configuration for performing the operation is provided.

  Then, the demapping unit 1021 switches between demapping processing based on the second constellation for the signal output from the subtraction unit 1019 and demapping processing based on the modified superposition constellation for the signal output from the RF unit 1030. . For example, the demapping unit 1021 switches between these demapping processes in accordance with a control signal from the control unit.

  Such a configuration is a combination of the receiving apparatus 400 shown in FIG. 11, the receiving apparatus 1000 (demapping unit 1021 etc.) shown in FIG. 18, and the receiving apparatus 1100 (demapping unit 1110 etc.) shown in FIG. Can also be obtained.

  As described above, when the SNR is high, the receiving apparatuses 800, 900, and 1000 can perform parallel decoding, thereby reducing the amount of calculation and reducing power consumption. Further, when the SNR is high, the receiving apparatuses 800, 900, and 1000 can reduce the processing delay by performing parallel decoding. On the other hand, when the SNR is low, the receiving apparatuses 800, 900, and 1000 increase the possibility of correctly decoding the second data series by performing sequential decoding.

  Comparing the transmission capacity of the multiplexing system using the superposition coding shown in FIG. 10 with the transmission capacity of the multiplexing system using the modified superposition coding shown in FIG. 23, the following matters are found.

  That is, the characteristics of transmission capacity by sequential decoding (solid line) are the same in the multiplexing scheme using superposition coding (FIG. 10) and the multiplexing scheme using modified superposition coding (FIG. 23). On the other hand, the characteristics of the transmission capacity by parallel decoding (broken line) are improved in the multiplexing method using modified superposition coding (FIG. 23) than the multiplexing method using superposition coding (FIG. 10). That is, a multiplexing scheme using modified superposition coding provides a desirable result in both the case of sequential decoding and the case of parallel decoding.

(Embodiment 4)
<Omission of encoding in sequential decoding (skip)>
In this embodiment, a reception method for skipping coding for generating a modulation symbol replica in sequential decoding of a signal obtained by superposition coding will be described. Here, skipping encoding means that encoding is omitted, that is, encoding is not performed. The configuration of the transmission apparatus is the same as that of the transmission apparatus 100 shown in FIG.

  FIG. 24 shows the reception of signals in which two data sequences are multiplexed in two layers using superimposition coding, and sequentially decodes them to obtain both or one of the two data sequences without re-encoding. 2 shows an example of a configuration of a receiving device 1200 that can perform the above processing. The configuration and operation of the receiving device 1200 will be described with reference to FIG.

  The receiving apparatus 1200 includes an RF unit 1230, a demapping unit 1211, a deinterleaving unit 1212, a decoding unit 1213, an interleaving unit 1215, a mapping unit 1216, a multiplying unit 1217, a delay unit 1218, a subtracting unit 1219, a demapping unit 1221, and a deinterleaving unit. Unit 1222 and decoding unit 1223. Each component may be a dedicated or general purpose circuit.

  The demapping unit 1211, the deinterleaving unit 1212, the decoding unit 1213, the interleaving unit 1215, the mapping unit 1216, the multiplication unit 1217, the delay unit 1218, the subtraction unit 1219, the demapping unit 1221, the deinterleaving unit 1222, and the decoding unit 1223 As a derivation unit. The RF unit 1230 can also be expressed as a receiving unit. The RF unit 1230 may include an antenna.

  The receiving device 1200 receives the multiplexed signal transmitted from the transmitting device 100 with an antenna and inputs it to the RF unit 1230. That is, the RF unit 1230 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 1230 is also expressed as a received signal, and includes a superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 1230 generates a baseband received signal from the received signal in the radio frequency band.

  The demapping unit 1211 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. At that time, the demapping unit 1211 treats a component corresponding to the second modulation symbol of the second data series as an unknown signal (noise) in the received signal including the superimposed modulation symbol sequence, and performs the first mapping scheme. Demapping is performed based on the first constellation.

Further, for example, the first constellation for demapping, amplitude coefficient a ₁ is reflected. The first bit likelihood sequence includes a first data portion corresponding to the first data series and a first error control portion corresponding to information for correcting an error. For example, the first error control part corresponds to parity.

  The deinterleaving unit 1212 rearranges the first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. This rearrangement is also called deinterleaving.

  Decoding section 1213 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence rearranged by deinterleaving section 1212, and outputs the decoding result as a first data sequence. . Specifically, the decoding unit 1213 performs error control decoding on the first bit likelihood sequence, thereby performing error-corrected first data portion, error-corrected first error control portion, A first bit string including is derived. Then, the decoding unit 1213 outputs the error-corrected first data portion as a first data series.

  When only the first data series is an acquisition target, the receiving device 1200 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, receiving apparatus 1200 acquires the second data series. Therefore, the following processing is performed.

  The interleaving unit 1215 rearranges the bit order of the first bit string derived by the decoding unit 1213 based on the first rearrangement rule. This rearrangement is also called interleaving.

  The mapping unit 1216 performs mapping processing according to the first mapping method on the first bit sequence rearranged by the interleaving unit 1215, and a first modulation symbol sequence composed of a plurality of first modulation symbols Is generated.

  When PSK modulation such as BPSK and QPSK, or QAM modulation such as 16QAM and 64QAM is used as the mapping method, the modulation symbol indicates, for example, the size of the in-phase component and the imaginary number indicates the size of the quadrature component. It can be represented by a complex number. When PAM modulation is used as the mapping method, the modulation symbol can be represented by a real number.

Multiplying unit 1217 multiplies the first amplitude coefficient _{a 1} in the first modulation symbol sequence mapping unit 1216 outputs.

  The delay unit 1218 outputs the received signal output from the RF unit 1230 from when the RF unit 1230 outputs the baseband received signal until the multiplier 1217 outputs the reproduced first modulation symbol sequence. Delay.

The subtractor 1219 subtracts the first modulation symbol string multiplied by the _first amplitude coefficient a ₁ by the multiplier 1217 from the received signal delayed by the delay unit 1218. As a result, the subtraction unit 1219 removes the component corresponding to the first modulation symbol from the reception signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 1219 outputs a signal in which a component corresponding to the second modulation symbol and noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The demapping unit 1221 demaps the signal output from the subtraction unit 1219 based on the second constellation of the second mapping scheme, and generates a second bit likelihood sequence. For example, the amplitude coefficient a ₂ is reflected in the second constellation for demapping. The second bit likelihood sequence includes a second data portion corresponding to the second data series and a second error control portion corresponding to information for correcting an error. For example, the second error control part corresponds to parity.

  The deinterleaving unit 1222 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving.

  Decoding section 1223 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 1222, and outputs the decoding result as a second data sequence. . Specifically, the decoding unit 1223 performs error control decoding on the second bit likelihood sequence, thereby performing error-corrected second data portion, error-corrected second error control portion, A second bit string including is derived. Then, the decoding unit 1223 outputs the error-corrected second data portion as a second data series.

  As described above, receiving apparatus 1200 acquires both or one of the first data series and the second data series from the signal received by the antenna.

  In order to compare the receiving apparatus 200 shown in FIG. 2 with the receiving apparatus 1200 shown in FIG. 24, first, a specific example of the operation of the receiving apparatus 200 shown in FIG. 2 will be described.

  FIG. 25 is a conceptual diagram illustrating a specific example of the operations of the transmission device 100 illustrated in FIG. 1 and the reception device 200 illustrated in FIG. In particular, FIG. 25 illustrates an operation from when the first data sequence is encoded by the transmission apparatus 100 to when a replica of the first modulation symbol of the first data series is generated by the reception apparatus 200 and canceled. Is shown.

  First, the encoding unit 111 of the transmission apparatus 100 generates a first bit string by performing error control encoding based on the first error control encoding scheme on a first data sequence including a plurality of bits. To do.

  The first bit string includes a first data portion corresponding to the first data series and a first error control portion corresponding to information for correcting an error. The first data part and the first error control part may not be clearly separated in the first bit string. An error control code in which a first data portion corresponding to the first data series and a first error control portion corresponding to information for correcting an error are clearly separated is referred to as a systematic code. An error control code that is not clearly divided is called a non-systematic code.

  For example, the encoding unit 111 generates a first bit string by performing a matrix operation on the first data series using a generator matrix (generation matrix). Specifically, the encoding unit 111 generates a first bit string by sequentially calculating a product of a predetermined number of bits in the first data series and a generator matrix.

  Next, interleaving section 112 of transmitting apparatus 100 rearranges a plurality of bits in the first bit string based on the first rearrangement rule. That is, interleaving section 112 interleaves a plurality of bits in the first bit string.

  Interleaving section 112 may rearrange a plurality of bits in the first data portion, or may rearrange a plurality of bits in the first error control portion. Further, the interleaving unit 112 may rearrange the bits of the first data portion and the bits of the first error control portion. Thereby, the first data portion and the first error control portion may be mixed.

  Then, in transmitting apparatus 100, mapping section 113 generates a first modulation symbol sequence by mapping the interleaved first bit sequence. Multiplier 114 multiplies the generated first modulation symbol string by an amplitude coefficient. Adder 130 superimposes the first modulation symbol sequence output from multiplication unit 114 and the second modulation symbol sequence output from multiplication unit 124. The RF unit 140 transmits a multiplexed signal in which the first modulation symbol sequence and the second modulation symbol sequence are superimposed.

  In the receiving apparatus 200, the RF unit 230 receives the multiplexed signal. The demapping unit 211 generates a first bit likelihood sequence including a first data part and a first error control part by demapping the multiplexed signal. The first bit likelihood sequence may include an error. An error may be included in the first data portion, and an error may be included in the first error control portion.

  Deinterleaving section 212 of receiving apparatus 200 rearranges a plurality of bits in the generated first bit likelihood sequence based on a rearrangement rule opposite to the first rearrangement rule. That is, deinterleaving section 212 deinterleaves a plurality of bits in the first bit likelihood sequence. The deinterleaving unit 212 may rearrange a plurality of bits in the first data portion, may rearrange a plurality of bits in the first error control portion, The bits of one error control part may be rearranged.

  Next, the decoding unit 213 of the receiving apparatus 200 performs error control decoding based on the first error control coding scheme on the rearranged first bit likelihood sequence, thereby performing error correction first. The bit string of is derived. The error-corrected first bit string includes the error-corrected first data portion and the error-corrected first error control portion, and is basically generated by the encoding unit 111 of the transmission apparatus 100. The same as the first bit string.

  For example, the decoding unit 213 detects an error by performing a matrix operation on the first bit likelihood sequence using a check matrix (check matrix). Specifically, the decoding unit 213 detects an error by sequentially using a product of a predetermined number of bits in the first bit likelihood sequence and the check matrix. Then, the decoding unit 213 derives the error-corrected first bit string by correcting the detected error. The decoding unit 213 may use a check matrix (check matrix) and perform decoding processing on the first bit likelihood sequence using an algorithm such as belief propagation or message passing.

  Then, the decoding unit 213 derives a first data sequence including the error-corrected first data portion in the error-corrected first bit string. Specifically, the decoding unit 213 derives the error-corrected first data portion of the error-corrected first bit string as a first data series.

  Next, encoding section 214 of receiving apparatus 200 generates a first bit string by performing error control encoding based on the first error control encoding scheme on the derived first data sequence. . That is, the encoding unit 214 of the receiving apparatus 200 performs error control encoding as in the encoding unit 111 of the transmitting apparatus 100, and generates a first bit string. The first bit string generated by the encoding unit 214 of the receiving apparatus 200 is basically the same as the first bit string generated by the encoding unit 111 of the transmitting apparatus 100.

  For example, the encoding unit 214 generates a first bit string by performing a matrix operation on the first data series using a generator matrix. Specifically, the encoding unit 214 generates a first bit string by sequentially calculating a product of a predetermined number of bits in the first data series and a generator matrix.

  Next, interleaving section 215 of receiving apparatus 200 rearranges a plurality of bits in the first bit string based on the first rearrangement rule. That is, interleaving section 215 of receiving apparatus 200 interleaves a plurality of bits in the first bit string in the same manner as interleaving section 112 of transmitting apparatus 100. The first bit string output by interleaving section 215 of receiving apparatus 200 is basically the same as the first bit string output by interleaving section 112 of transmitting apparatus 100.

  Thereafter, in receiving apparatus 200, mapping section 216 generates a first modulation symbol sequence by mapping the interleaved first bit sequence. Multiplier 217 multiplies the generated first modulation symbol string by an amplitude coefficient. The subtraction unit 219 cancels the first modulation symbol sequence from the multiplexed signal by subtracting the first modulation symbol sequence output from the multiplication unit 217 from the multiplexed signal output from the delay unit 218. The receiving apparatus 200 can derive the second data series from the multiplexed signal from which the first modulation symbol sequence is canceled.

  A first bit string generated by performing error control decoding on the first bit likelihood string, and a first bit string generated by performing error control coding on the first data sequence; Are basically the same. Therefore, receiving apparatus 1200 does not perform error control coding on the first data sequence.

  FIG. 26 is a conceptual diagram showing a specific example of the operation of transmitting apparatus 100 shown in FIG. 1 and receiving apparatus 1200 shown in FIG. In particular, FIG. 26 illustrates an operation from when the first data sequence is encoded by the transmission apparatus 100 until a replica of the first modulation symbol of the first data series is generated and canceled by the reception apparatus 1200. Is shown.

  First, transmission apparatus 100 and reception apparatus 1200 generate a first bit string by error control decoding for the first bit likelihood string after a first bit string is generated by error control coding for the first data series. Until it is done, the processing is performed in the same manner as in the example of FIG.

  Then, interleaving section 1215 of receiving apparatus 1200 rearranges the plurality of bits in the error-corrected first bit string based on the first rearrangement rule. That is, interleaving section 1215 of receiving apparatus 1200 interleaves a plurality of bits in the error-corrected first bit string in the same manner as interleaving section 112 of transmitting apparatus 100. The error-corrected first bit string includes an error-corrected first data portion and an error-corrected first error control portion.

  That is, interleaving section 1215 of receiving apparatus 1200 performs error control decoding on the first bit likelihood sequence, not on the first bit sequence generated by performing error control coding on the first data sequence. The first bit string generated by performing is rearranged. The first bit string output by interleaving section 1215 of receiving apparatus 1200 is basically the same as the first bit string output by interleaving section 112 of transmitting apparatus 100.

  Thereafter, the receiving apparatus 1200 generates a first modulation symbol by mapping, subtracts the first modulation symbol sequence from the multiplexed signal, and generates a second data sequence from the multiplexed signal from which the first modulation symbol sequence is canceled. Until it is derived, the same processing as in the example of FIG. 25 is performed.

  Accordingly, receiving apparatus 1200 can derive the second data sequence by skipping error control coding for the first data sequence in the sequential decoding of the signal obtained by the superposition coding.

  In receiving apparatus 1200, rearrangement (interleaving and deinterleaving) may be omitted as in the first embodiment. That is, the interleaving unit 1215 and the deinterleaving units 1212 and 1222 are arbitrary components and may not be included in the receiving device 1200.

In the receiving apparatus 1200, the amplitude coefficients a ₁ to a mapping for generating a first modulation symbol may be reflected. In this case, multiplication of the amplitude coefficients a ₁ may be omitted. The receiving apparatus 1200 may not include the multiplication unit 1217.

  Also, the generator matrix used in error control coding and the check matrix used in error control decoding are examples. Error control coding and error control decoding may be performed according to other error control coding schemes that do not use a generator matrix or a check matrix.

  Basically, the first mapping method and the second mapping method in the present embodiment are the same as the first mapping method and the second mapping method in the first embodiment. That is, basically, the first constellation and the second constellation in the present embodiment are the same as the first constellation and the second constellation in the first embodiment. For the second mapping scheme, a uniform constellation may be used, or a non-uniform constellation may be used.

  In the systematic code, the error-corrected first error control portion is derived when the error-corrected first data portion is derived as the first data sequence by error control decoding. Therefore, omission of re-encoding is particularly effective for systematic codes. On the other hand, even in a non-systematic code, in the process of error control decoding, the first bit string including the first data part corrected in error and the first error control part corrected in error (without distinction) is included. Once derived, re-encoding can be omitted.

  FIG. 27 is a flowchart illustrating an operation example of the reception device 1200 illustrated in FIG. First, the RF unit 1230 receives a multiplexed signal that is a signal in which the first data series and the second data series are multiplexed (S501).

  Next, the demapping unit 1211 demaps the received multiplexed signal, thereby performing a first bit likelihood including a first data portion corresponding to the first data sequence and a first error control portion. A degree sequence is generated (S502). Next, the deinterleaving unit 1212 deinterleaves the generated first bit likelihood sequence (S503).

  Next, the decoding unit 1213 performs error control decoding on the deinterleaved first bit likelihood sequence, thereby performing error-corrected first data portion and error-corrected first error control. A first bit string including the portion is derived (S504). Then, the decoding unit 1213 derives a first data series including the error-corrected first data portion (S505).

Next, the interleaving unit 1215 interleaves the first bit string including the error-corrected first data portion and the error-corrected first error control portion (S506). Next, the mapping unit 1216 maps the interleaved first bit string (the first bit string including the error-corrected first data part and the error-corrected first error control part). Then, a first modulation symbol string is generated (S507). Multiplying unit 1217, a first modulation symbol sequence may be multiplied by the amplitude coefficient a _1.

  Also, the delay unit 1218 delays the received multiplexed signal until the first modulation symbol sequence is generated (S508). Note that the process of delaying the received multiplexed signal is performed in parallel with the process from the generation of the first bit likelihood sequence to the generation of the first modulation symbol sequence. Then, the subtraction unit 1219 subtracts the first modulation symbol sequence from the multiplexed signal (S509).

  Next, the demapping unit 1221 demaps the multiplexed signal from which the first modulation symbol sequence has been subtracted, so that the second data part corresponding to the second data sequence, the second error control part, A second bit likelihood sequence including is generated (S510). The deinterleaving unit 1222 deinterleaves the generated second bit likelihood sequence (S511).

  Next, the decoding unit 1223 derives a second data sequence including the error-corrected second data portion by performing error control decoding on the deinterleaved second bit likelihood sequence ( S512).

  The encoding skip in the sequential decoding may be applied to a combination of parallel decoding and sequential decoding (FIG. 11). The encoding skip in the sequential decoding may be applied to the sequential decoding (FIGS. 16, 17 and 18) corresponding to the modified superposition encoding. Also, encoding skip in sequential decoding, parallel decoding, and sequential decoding corresponding to modified superposition encoding may be combined.

  FIG. 28 shows an example of a configuration of a receiving apparatus 1300 that selectively performs parallel decoding and sequential decoding and skips encoding in sequential decoding.

  The receiving apparatus 1300 includes an RF unit 1330, a demapping unit 1311, a deinterleaving unit 1312, a decoding unit 1313, an interleaving unit 1315, a mapping unit 1316, a multiplying unit 1317, a delay unit 1318, a subtracting unit 1319, a demapping unit 1321, and a deinterleaving unit. And a decoding unit 1323.

  A plurality of components of the receiving device 1300 illustrated in FIG. 28 are basically the same as the components of the receiving device 1200 illustrated in FIG. 24 except for the demapping unit 1321. The demapping unit 1321 of the receiving apparatus 1300 illustrated in FIG. 28 is basically the same as the demapping unit 421 of the receiving apparatus 400 illustrated in FIG.

  For example, if the signal-to-noise ratio of the multiplexed signal satisfies a predetermined criterion, the demapping unit 1321 demaps the multiplexed signal in a state where the multiplexed signal includes the first modulation symbol sequence as an undetermined signal component. As a result, a second bit likelihood sequence is generated. Then, when the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion, the demapping unit 1321 demaps the multiplexed signal from which the first modulation symbol sequence is subtracted, thereby generating the second bit likelihood sequence. Is generated.

  With the configuration as described above, receiving apparatus 1300 can reduce a processing delay that occurs in sequential decoding combined with parallel decoding.

  In FIG. 29, a signal in which two data sequences are multiplexed into two layers using modified superposition coding is received and sequentially decoded, and both or one of the two data sequences is not re-encoded. An example of a configuration of a receiving device 1400 that can be acquired is shown.

  The receiving apparatus 1400 includes an RF unit 1430, a demapping unit 1411, a deinterleaving unit 1412, a decoding unit 1413, an interleaving unit 1415, a mapping unit 1416, a multiplying unit 1417, a delay unit 1418, a subtracting unit 1419, a demapping unit 1421, and a deinterleaving unit. Unit 1422 and decoding unit 1423.

  A plurality of components of receiving apparatus 1400 shown in FIG. 29 are basically the same as the plurality of components of receiving apparatus 1200 shown in FIG. 24 except for RF unit 1430 and conversion unit 1420. 29 is basically the same as RF unit 830 and conversion unit 820 of reception apparatus 800 shown in FIG.

  For example, in the multiplexed signal received by the RF unit 1430, a first modulation symbol sequence and a second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string. The conversion unit 1420 converts the multiplexed signal corresponding to the second modulation symbol sequence in accordance with the interleaved first bit sequence, thereby converting the conversion corresponding to the first bit sequence into the second bit likelihood sequence. Bring.

  With the configuration as described above, receiving apparatus 1400 can reduce a processing delay that occurs in sequential decoding corresponding to modified superposition coding.

  In the above configuration example, receiving apparatus 1400 converts the multiplexed signal according to the first bit string, thereby bringing the conversion according to the first bit string into the second bit likelihood string. Instead of this, as in the receiving apparatus 900, conversion according to the first bit string may be provided to the second bit string by converting the multiplexed signal according to the first modulation symbol string.

  Alternatively, like the receiving apparatus 1000, the second bit likelihood sequence or the second mapping scheme (second constellation) may be converted according to the first modulation symbol sequence. Thereby, a conversion corresponding to the first bit string may be provided to the second bit likelihood string. In this case, before the second bit likelihood sequence is generated, the second bit sequence or the second mapping scheme is converted.

  That is, by converting the second bit likelihood sequence, the second mapping scheme, or the multiplexed signal according to the first bit sequence or the first modulation symbol sequence, the conversion according to the first bit sequence is performed in the second manner. Of the bit likelihood sequence.

  FIG. 30 shows a case where a signal in which two data sequences are multiplexed in two layers is received using modified superposition coding, sequentially decoded, and both and / or one of the two data sequences is not re-encoded. An example of a configuration of a receiving device 1500 that can be acquired is shown. The configuration of receiving apparatus 1500 is different from the configuration of receiving apparatus 1400.

  The receiving device 1500 includes an RF unit 1530, a demapping unit 1511, a deinterleaving unit 1512, a decoding unit 1513, an interleaving unit 1515, a mapping unit 1516, a multiplying unit 1517, a delay unit 1518, a subtracting unit 1519, a demapping unit 1521, and a deinterleaving unit. Part 1522 and decoding part 1523.

  A plurality of components of receiving apparatus 1500 shown in FIG. 30 are basically the same as the plurality of components of receiving apparatus 1200 shown in FIG. 24 except for RF unit 1530 and conversion unit 1520. The RF unit 1530 and the conversion unit 1520 of the reception device 1500 illustrated in FIG. 30 are basically the same as the RF unit 930 and the conversion unit 920 of the reception device 900 illustrated in FIG.

  For example, in the multiplexed signal received by the RF unit 1530, a first modulation symbol sequence and a second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string. The conversion unit 1520 converts the multiplexed signal corresponding to the second modulation symbol sequence in accordance with the generated first modulation symbol sequence, thereby performing the conversion corresponding to the first bit sequence to the second bit likelihood. Bring to the column.

  With the configuration as described above, receiving apparatus 1500 can reduce a processing delay that occurs in successive decoding corresponding to modified superposition coding.

  FIG. 31 shows a case where a signal in which two data sequences are multiplexed in two layers is received using modified superposition coding, sequentially decoded, and both and / or one of the two data sequences is not re-encoded. An example of a configuration of a receiving device 1600 that can be acquired is shown. The configuration of receiving apparatus 1600 is different from the configuration of receiving apparatuses 1400 and 1500.

  The receiving apparatus 1600 includes an RF unit 1630, a demapping unit 1611, a deinterleaving unit 1612, a decoding unit 1613, an interleaving unit 1615, a mapping unit 1616, a multiplying unit 1617, a delay unit 1618, a subtracting unit 1619, a demapping unit 1621, and a deinterleaving unit. Unit 1622 and decoding unit 1623.

  A plurality of components of receiving apparatus 1600 shown in FIG. 31 are basically the same as the plurality of components of receiving apparatus 1200 shown in FIG. 24 except for RF unit 1630 and demapping unit 1621. 31 is basically the same as the RF unit 1030 and the demapping unit 1021 of the receiving apparatus 1000 shown in FIG.

  For example, in the multiplexed signal received by the RF unit 1630, a first modulation symbol sequence and a second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string.

  The demapping unit 1621 converts the second bit likelihood sequence or the second mapping scheme (second constellation) in accordance with the interleaved first bit sequence, thereby depending on the first bit sequence. Bring the transformation to the second bit likelihood sequence. Note that the conversion unit in the demapping unit 1621 may bring the conversion corresponding to the first bit string to the second bit likelihood string.

  With the configuration as described above, receiving apparatus 1600 can reduce a processing delay that occurs in sequential decoding corresponding to modified superposition coding.

  In the present embodiment, the first modulation symbol sequence for subtraction is generated without performing error control coding on the first data sequence derived from the multiplexed signal. Accordingly, it is possible to reduce the amount of calculation and components for error control coding. In addition, a first modulation symbol sequence is generated using the first bit sequence that has been error-corrected in error control decoding. Therefore, processing delay can be suppressed.

(Embodiment 5)
<Omission of encoding and interleaving in sequential decoding (skip)>
In this embodiment, a reception method for skipping encoding and interleaving for generating a replica of a modulation symbol in sequential decoding of a signal obtained by superposition coding will be described. Here, skipping encoding and interleaving means that encoding and interleaving are omitted, that is, encoding and interleaving are not performed. The configuration of the transmission apparatus is the same as that of the transmission apparatus 100 shown in FIG.

  FIG. 32 shows the reception of a signal in which two data sequences are multiplexed in two layers using superposition coding, and sequentially decodes and acquires both or one of the two data sequences without re-encoding. 3 shows an example of a configuration of a receiving device 1700 that can perform the above. The configuration and operation of the receiving apparatus 1700 will be described with reference to FIG.

  Receiving apparatus 1700 includes RF unit 1730, demapping unit 1711, decoding unit 1713, deinterleaving unit 1712, mapping unit 1716, multiplication unit 1717, delay unit 1718, subtraction unit 1719, demapping unit 1721, deinterleaving unit 1722, and decoding unit. A portion 1723 is provided. Each component may be a dedicated or general purpose circuit.

  The demapping unit 1711, the decoding unit 1713, the deinterleaving unit 1712, the mapping unit 1716, the multiplication unit 1717, the delay unit 1718, the subtraction unit 1719, the demapping unit 1721, the deinterleaving unit 1722, and the decoding unit 1723 are generally used as the derivation unit. Can be expressed. The RF unit 1730 can also be expressed as a receiving unit. The RF unit 1730 may include an antenna.

  The receiving apparatus 1700 receives the multiplexed signal transmitted from the transmitting apparatus 100 with an antenna and inputs it to the RF unit 1730. That is, the RF unit 1730 receives the multiplexed signal via the antenna. The multiplexed signal received by the RF unit 1730 is also expressed as a received signal, and includes a superimposed modulation symbol sequence in which the first modulation symbol sequence and the second modulation symbol sequence are multiplexed. The RF unit 1730 generates a baseband received signal from the received signal in the radio frequency band.

  The demapping unit 1711 demaps the baseband received signal based on the first constellation of the first mapping scheme, and generates a first bit likelihood sequence. At that time, the demapping unit 1711 treats a component corresponding to the second modulation symbol of the second data series as an unknown signal (noise) in the received signal including the superimposed modulation symbol sequence, and performs the first mapping method. Demapping is performed based on the first constellation.

Further, for example, the first constellation for demapping, amplitude coefficient a ₁ is reflected. The first bit likelihood sequence includes a first data portion corresponding to the first data series and a first error control portion corresponding to information for correcting an error. For example, the first error control part corresponds to parity.

  The decoding unit 1713 performs a decoding process based on the first error control coding scheme using the first bit likelihood sequence generated by the demapping unit 1711. Specifically, the decoding unit 1713 derives an error-corrected first bit string by performing error control decoding on the first bit likelihood string. The error-corrected first bit string includes an error-corrected first data portion and an error-corrected first error control portion. Here, the decoding unit 1713 performs a decoding process using the check matrix interleaved based on the first rearrangement rule.

  When the first data series is an acquisition target, the decoding unit 1713 outputs the error-corrected first bit string to the deinterleaving unit 1712. When the second data series is an acquisition target, the decoding unit 1713 outputs the error-corrected first bit string to the mapping unit 1716. When both the first data series and the second data series are to be acquired, the error-corrected first bit string is output to both the deinterleaving unit 1712 and the mapping unit 1716.

  When the decoding unit 1713 outputs the error-corrected first bit string to the deinterleaving unit 1712, only the error-corrected first data portion of the error-corrected first bit string is output to the deinterleaving unit 1712. It may be output.

  When the first data series is an acquisition target, the deinterleaving unit 1712 rearranges the error-corrected first bit string based on a rearrangement rule opposite to the first rearrangement rule. The deinterleaving unit 1712 may rearrange only the first data portion subjected to error correction in the first bit string subjected to error correction. This rearrangement is also called deinterleaving. The deinterleaving unit 1712 outputs the rearranged first data portion as a first data series.

  When the first data series is not an acquisition target, the deinterleaving unit 1712 may not perform deinterleaving (rearrangement), and may not output the first data series. When the first data series is not always the acquisition target and only the second data series is the acquisition target, the receiving apparatus 1700 may not include the deinterleaving unit 1712.

  If only the first data series is the acquisition target, the receiving apparatus 1700 ends the process when the estimation of the first data series is completed. On the other hand, when the second data series is the acquisition target in addition to the first data series, or when only the second data series is the acquisition target, receiving apparatus 1700 acquires the second data series. Therefore, the following processing is performed.

  The mapping unit 1716 performs mapping processing according to the first mapping method on the error-corrected first bit string, and generates a first modulation symbol string composed of a plurality of first modulation symbols.

  When PSK modulation such as BPSK and QPSK, or QAM modulation such as 16QAM and 64QAM is used as the mapping method, the modulation symbol indicates, for example, the size of the in-phase component and the imaginary number indicates the size of the quadrature component. It can be represented by a complex number. When PAM modulation is used as the mapping method, the modulation symbol can be represented by a real number.

Multiplying unit 1717 multiplies the first amplitude coefficient _{a 1} in the first modulation symbol sequence output from the mapping unit 1716.

  The delay unit 1718 outputs the reception signal output from the RF unit 1730 from when the RF unit 1730 outputs the baseband reception signal until the multiplication unit 1717 outputs the reproduced first modulation symbol sequence. Delay.

The subtraction unit 1719 subtracts the first modulation symbol string multiplied by the _first amplitude coefficient a ₁ by the multiplication unit 1717 from the reception signal delayed by the delay unit 1718. As a result, the subtraction unit 1719 removes the component corresponding to the first modulation symbol from the reception signal in which the component corresponding to the first modulation symbol, the component corresponding to the second modulation symbol, and the noise are superimposed. . Then, the subtraction unit 1719 outputs a signal in which a component corresponding to the second modulation symbol and noise are superimposed as a signal corresponding to the second modulation symbol sequence.

The demapping unit 1721 demaps the signal output from the subtracting unit 1719 based on the second constellation of the second mapping scheme, and generates a second bit likelihood sequence. For example, the amplitude coefficient a ₂ is reflected in the second constellation for demapping. The second bit likelihood sequence includes a second data portion corresponding to the second data series and a second error control portion corresponding to information for correcting an error. For example, the second error control part corresponds to parity.

  The deinterleaving unit 1722 rearranges the second bit likelihood sequence based on a rearrangement rule opposite to the second rearrangement rule. This rearrangement is also called deinterleaving.

  Decoding section 1723 performs decoding processing based on the second error control coding scheme on the second bit likelihood sequence rearranged by deinterleaving section 1722, and outputs the decoding result as a second data sequence. . Specifically, the decoding unit 1723 performs error control decoding on the second bit likelihood sequence, thereby performing error-corrected second data portion, error-corrected second error control portion, A second bit string including is derived. Then, the decoding unit 1723 outputs the error-corrected second data portion as a second data series.

  As described above, receiving apparatus 1700 acquires both or one of the first data series and the second data series from the signal received by the antenna.

  FIG. 33 is a conceptual diagram showing a specific example of the operation of transmitting apparatus 100 shown in FIG. 1 and receiving apparatus 1700 shown in FIG. In particular, FIG. 33 shows operations from when the first data sequence is encoded by the transmission apparatus 100 until the reception apparatus 1700 generates a replica of the first modulation symbol of the first data series and cancels it. Is shown.

  First, the transmission apparatus 100 and the reception apparatus 1700 are configured until the first bit likelihood sequence is generated by demapping after the first bit sequence is generated by error control coding on the first data sequence. The processing is performed in the same manner as the examples in FIGS.

  Then, the decoding unit 1713 of the reception device 1700 performs error correction decoding on the first bit likelihood sequence generated by demapping to derive the error-corrected first bit sequence. Specifically, the decoding unit 1713 performs error correction decoding on the first bit likelihood sequence based on the modified first error control encoding scheme.

  The first bit string derived by the decoding unit 1713 of the receiving apparatus 1700 includes a first data part that has been error-corrected and a first error control part that has been error-corrected. Also, the first bit string derived by the decoding unit 1713 of the receiving apparatus 1700 is basically the same as the first bit string interleaved by the interleaving unit 112 of the transmitting apparatus 100.

  For example, a check matrix (check matrix) based on the first error control coding scheme is interleaved based on the first rearrangement rule. That is, the check matrix corresponding to the generator matrix (generation matrix) for generating the first bit string in the transmission device 100 is interleaved based on the first rearrangement rule. Specifically, a plurality of columns of the check matrix are interleaved based on the first rearrangement rule.

  Then, the decoding unit 1713 detects an error by performing a matrix operation on the first bit likelihood sequence using the check matrix interleaved based on the first rearrangement rule. Specifically, decoding section 1713 detects an error by sequentially using a product of a predetermined number of bits in the first bit likelihood sequence and the interleaved check matrix. Then, the decoding unit 1713 corrects the detected error to derive the error-corrected first bit string. The decoding unit 1713 uses a check matrix (check matrix) interleaved based on the first rearrangement rule, and applies algorithms such as probability propagation and message passing to the first bit likelihood sequence. The decryption process may be performed by using them.

  That is, the receiving apparatus 1700 uses the check matrix interleaved based on the first rearrangement rule without interleaving the first bit likelihood sequence based on the first rearrangement rule. Error control decoding is performed on the likelihood sequence. As a result, receiving apparatus 1700 can derive the first bit string that is basically the same as the first bit string interleaved by interleaving section 112 of transmitting apparatus 100 without interleaving the first bit likelihood string. it can.

  Then, mapping section 1716 of receiving apparatus 1700 generates the first modulation symbol string by mapping the first bit string derived without performing interleaving in receiving apparatus 1700. Thereafter, the receiving apparatus 1700 subtracts the first modulation symbol sequence from the multiplexed signal and continues to derive the second data sequence from the multiplexed signal from which the first modulation symbol sequence is canceled. Process in the same way as

  Thus, receiving apparatus 1700 can derive the second data sequence by skipping error control coding and interleaving in the sequential decoding of the signal obtained by superposition coding.

Incidentally, in the receiving apparatus 1700, the amplitude coefficients a ₁ to a mapping for generating a first modulation symbol may be reflected. In this case, multiplication of the amplitude coefficients a ₁ may be omitted. The receiving apparatus 1700 may not include the multiplication unit 1717.

  Similarly to the decoding unit 1713, the decoding unit 1723 may perform error control decoding using the interleaved check matrix before the deinterleaving unit 1722 performs deinterleaving. The deinterleaving unit 1722 may derive the second data sequence by deinterleaving the error-corrected second bit string.

  Also, the generator matrix used in error control coding and the check matrix used in error control decoding are examples. Error control coding and error control decoding may be performed according to other error control coding schemes that do not use a generator matrix or a check matrix. In order to perform error control decoding without deinterleaving the first bit likelihood sequence, the error control coding scheme may be partially changed. For example, a combination of a plurality of bits subject to error detection may be changed.

  Basically, the first mapping method and the second mapping method in the present embodiment are the same as the first mapping method and the second mapping method in the first embodiment. That is, basically, the first constellation and the second constellation in the present embodiment are the same as the first constellation and the second constellation in the first embodiment. For the second mapping scheme, a uniform constellation may be used, or a non-uniform constellation may be used.

  FIG. 34 is a flowchart showing an operation example of the receiving apparatus 1700 shown in FIG. First, the RF unit 1730 receives a multiplexed signal that is a signal in which the first data series and the second data series are multiplexed (S601).

  Next, the demapping unit 1711 demaps the received multiplexed signal, thereby performing a first bit likelihood including a first data portion corresponding to the first data sequence and a first error control portion. A degree sequence is generated (S602). Next, the decoding unit 1713 performs error control decoding on the generated first bit likelihood sequence, thereby error-corrected first data portion and error-corrected first error control portion. A first bit string including is derived (S603).

  Next, the deinterleaving unit 1712 derives a first data sequence by deinterleaving the error-corrected first data portion (S604).

Next, mapping section 1716 generates a first modulation symbol sequence by mapping the first bit sequence including the error-corrected first data portion and the error-corrected first error control portion. (S605). Multiplying unit 1717, a first modulation symbol sequence may be multiplied by the amplitude coefficient a _1.

  The delay unit 1718 delays the received multiplexed signal until the first modulation symbol sequence is generated (S606). Note that the process of delaying the received multiplexed signal is performed in parallel with the process from the generation of the first bit likelihood sequence to the generation of the first modulation symbol sequence. Then, the subtraction unit 1719 subtracts the first modulation symbol sequence from the multiplexed signal (S607).

  Next, the demapping unit 1721 demaps the multiplexed signal from which the first modulation symbol sequence has been subtracted, whereby a second data part corresponding to the second data sequence, a second error control part, A second bit likelihood sequence including is generated (S608). The deinterleaving unit 1722 deinterleaves the generated second bit likelihood sequence (S609).

  Next, the decoding unit 1723 derives a second data series including the error-corrected second data portion by performing error control decoding on the deinterleaved second bit likelihood sequence ( S610).

  Coding and interleaving skip in sequential decoding may be applied to a combination of parallel decoding and sequential decoding (FIG. 11). Also, encoding and interleaving skip in sequential decoding may be applied to sequential decoding (FIGS. 16, 17 and 18) corresponding to modified superposition encoding. Also, encoding and interleaving skip in sequential decoding, parallel decoding, and sequential decoding corresponding to modified superposition coding may be combined.

  FIG. 35 illustrates an example of a configuration of a reception device 1800 that selectively performs parallel decoding and sequential decoding and skips encoding in sequential decoding.

  A receiving apparatus 1800 includes an RF unit 1830, a demapping unit 1811, a decoding unit 1813, a deinterleaving unit 1812, a mapping unit 1816, a multiplying unit 1817, a delay unit 1818, a subtracting unit 1819, a demapping unit 1821, a deinterleaving unit 1822, and a decoding unit. A portion 1823 is provided.

  A plurality of components of receiving apparatus 1800 shown in FIG. 35 are basically the same as the plurality of components of receiving apparatus 1700 shown in FIG. 32 except for demapping unit 1821. The demapping unit 1821 of the receiving apparatus 1800 illustrated in FIG. 35 is basically the same as the demapping unit 421 of the receiving apparatus 400 illustrated in FIG.

  For example, when the signal-to-noise ratio of the multiplexed signal satisfies a predetermined criterion, the demapping unit 1821 demaps the multiplexed signal in a state where the multiplexed signal includes the first modulation symbol sequence as an undetermined signal component. As a result, a second bit likelihood sequence is generated. Then, when the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion, the demapping unit 1821 demaps the multiplexed signal from which the first modulation symbol sequence is subtracted, thereby generating the second bit likelihood sequence. Is generated.

  With the configuration as described above, receiving apparatus 1800 can reduce a processing delay that occurs in sequential decoding combined with parallel decoding.

  FIG. 36 shows a case where a signal in which two data sequences are multiplexed in two layers is received using modified superposition coding, sequentially decoded, and either or one of the two data sequences is not re-encoded. An example of a configuration of a receiving device 1900 that can be acquired is shown.

  Receiving apparatus 1900 includes RF section 1930, demapping section 1911, decoding section 1913, deinterleaving section 1912, mapping section 1916, multiplication section 1917, delay section 1918, subtraction section 1919, demapping section 1921, deinterleaving section 1922, and decoding. A portion 1923 is provided.

  36 are basically the same as the plurality of components of the reception apparatus 1700 shown in FIG. 32 except for the RF unit 1930 and the conversion unit 1920. 36 is basically the same as RF unit 830 and conversion unit 820 of reception apparatus 800 shown in FIG.

  For example, in the multiplexed signal received by the RF unit 1930, the first modulation symbol sequence and the second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string. The conversion unit 1920 converts the multiplexed signal corresponding to the second modulation symbol sequence in accordance with the error-corrected first bit sequence, thereby converting the second bit likelihood sequence according to the first bit sequence. To bring.

  With the configuration as described above, receiving apparatus 1900 can reduce a processing delay that occurs in sequential decoding corresponding to modified superposition coding.

  In the configuration example described above, the receiving apparatus 1900 converts the multiplexed signal according to the first bit string, thereby bringing the second bit likelihood string into conversion according to the first bit string. Instead of this, as in the receiving apparatus 900, conversion according to the first bit string may be provided to the second bit string by converting the multiplexed signal according to the first modulation symbol string.

  Alternatively, like the receiving apparatus 1000, the second bit likelihood sequence or the second mapping scheme (second constellation) may be converted according to the first modulation symbol sequence. Thereby, a conversion corresponding to the first bit string may be provided to the second bit likelihood string. In this case, before the second bit likelihood sequence is generated, the second bit sequence or the second mapping scheme is converted.

  That is, by converting the second bit likelihood sequence, the second mapping scheme, or the multiplexed signal according to the first bit sequence or the first modulation symbol sequence, the conversion according to the first bit sequence is performed in the second manner. Of the bit likelihood sequence.

  FIG. 37 shows a case where a signal in which two data sequences are multiplexed in two layers is received using modified superposition coding, sequentially decoded, and both or one of the two data sequences is not re-encoded. An example of the structure of the receiving device 2000 which can be acquired is shown. The configuration of receiving apparatus 2000 is different from the configuration of receiving apparatus 1900.

  The receiving apparatus 2000 includes an RF unit 2030, a demapping unit 2011, a decoding unit 2013, a deinterleaving unit 2012, a mapping unit 2016, a multiplication unit 2017, a delay unit 2018, a subtraction unit 2019, a demapping unit 2021, a deinterleaving unit 2022, and a decoding unit. Part 2023.

  37 are basically the same as the plurality of components of the reception apparatus 1700 shown in FIG. 32 except for the RF unit 2030 and the conversion unit 2020. The RF unit 2030 and the conversion unit 2020 of the reception device 2000 illustrated in FIG. 37 are basically the same as the RF unit 930 and the conversion unit 920 of the reception device 900 illustrated in FIG.

  For example, in the multiplexed signal received by the RF unit 2030, the first modulation symbol sequence and the second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string. The conversion unit 2020 converts the multiplexed signal corresponding to the second modulation symbol sequence according to the generated first modulation symbol sequence, thereby performing the conversion corresponding to the first bit sequence to the second bit likelihood. Bring to the column.

  With the configuration as described above, receiving apparatus 2000 can reduce processing delays that occur in sequential decoding corresponding to modified superposition coding.

  FIG. 38 shows a case where a signal in which two data sequences are multiplexed in two layers is received using modified superposition coding, sequentially decoded, and both and / or one of the two data sequences is not re-encoded. An example of a configuration of a receiving device 2100 that can be acquired is shown. The configuration of receiving apparatus 2100 is different from the configuration of receiving apparatuses 1900 and 2000.

  The reception apparatus 2100 includes an RF unit 2130, a demapping unit 2111, a deinterleaving unit 2112, a decoding unit 2113, a mapping unit 2116, a multiplication unit 2117, a delay unit 2118, a subtraction unit 2119, a demapping unit 2121, a deinterleaving unit 2122, and a decoding unit. Part 2123 is provided.

  A plurality of components of the receiving apparatus 2100 illustrated in FIG. 38 are basically the same as the plurality of components of the receiving apparatus 1700 illustrated in FIG. 32 except for the RF unit 2130 and the demapping unit 2121. The RF unit 2130 and demapping unit 2121 of the receiving apparatus 2100 shown in FIG. 38 are basically the same as the RF unit 1030 and demapping unit 1021 of the receiving apparatus 1000 shown in FIG.

  For example, in the multiplexed signal received by the RF unit 2130, a first modulation symbol sequence and a second modulation symbol sequence are superimposed at a predetermined amplitude ratio, and the real part and imaginary number of each modulation symbol in the second modulation symbol sequence This is a signal whose polarity is controlled in accordance with the first modulation symbol string.

  The demapping unit 2121 converts the second bit likelihood sequence or the second mapping scheme (second constellation) in accordance with the error-corrected first bit sequence, and thereby responds to the first bit sequence. The resulting transformation into the second bit likelihood sequence. Note that the conversion unit in the demapping unit 2121 may bring the conversion corresponding to the first bit string to the second bit likelihood string.

  With the configuration as described above, the receiving apparatus 2100 can reduce a processing delay that occurs in the sequential decoding corresponding to the modified superposition coding.

  In the present embodiment, the first modulation symbol sequence for subtraction is generated without performing error control coding and interleaving on the first data sequence derived from the multiplexed signal. Therefore, it is possible to reduce the amount of computation and components for error control coding and interleaving. Also, a first modulation symbol sequence is generated using the first bit sequence that has been error-corrected in error control decoding before deinterleaving. Therefore, processing delay can be suppressed.

  As described above, in the reception device according to one aspect of the present disclosure, a plurality of data sequences including the first data sequence of the first hierarchy and the second data sequence of the second hierarchy are multiplexed by superposition coding. A receiving device that receives a multiplexed signal that is a signal, a receiving unit that receives the multiplexed signal, and a first data portion corresponding to the first data sequence by demapping the multiplexed signal; A first demapping unit that generates a first bit likelihood sequence including a first error control portion, and error control decoding is performed on the first bit likelihood sequence to correct the error A first decoding unit for deriving a first bit string including the first data part and the error-corrected first error control part; the error-corrected first data part; and error correction Said first error control part Mapping the first bit sequence, a mapping unit for generating a first modulation symbol sequence, a delay unit for delaying the multiplexed signal received by the reception unit, and a delay unit delayed by the delay unit A subtracting unit that subtracts the first modulation symbol sequence from the multiplexed signal and a second signal corresponding to the second data sequence by demapping the multiplexed signal obtained by subtracting the first modulation symbol sequence. A second demapping unit that generates a second bit likelihood sequence including a data portion and a second error control portion, and performing error control decoding on the second bit likelihood sequence And a second decoding unit for deriving the second data series including the second data portion subjected to error correction.

  As a result, the reception device generates the first modulation symbol sequence of the first data sequence without encoding the first data sequence at the reception device, and uses the generated first modulation symbol sequence to generate the first modulation symbol sequence. Two data series can be acquired. Therefore, processing delay can be suppressed. That is, the receiving apparatus can perform efficient processing with respect to a multiplexing scheme using superposition coding.

  For example, the receiving apparatus further derives the first data sequence including the first data portion that has been error-corrected and deinterleaved by deinterleaving the first data portion that has been error-corrected. A deinterleaving unit may be provided.

  Thereby, the receiving apparatus can perform error control decoding before deinterleaving. Therefore, the receiving apparatus can further reduce the time for generating the first modulation symbol sequence in the receiving apparatus, and can suppress processing delay.

  Further, for example, the receiving device further includes a deinterleaving unit that deinterleaves the first bit likelihood sequence generated by demapping the multiplexed signal, and the first decoding unit includes a deinterleaving unit. By performing error control decoding on the interleaved first bit likelihood sequence, the first bit sequence is derived, and the receiving apparatus further performs interleaving for interleaving the derived first bit sequence And the mapping unit may generate the first modulation symbol string by mapping the interleaved first bit string.

  As a result, the receiving apparatus can perform error control decoding after deinterleaving. Therefore, the receiving apparatus can perform error control decoding after rearranging the bit likelihood sequences in an order suitable for error control decoding.

  For example, the second demapping unit may be configured such that when the signal-to-noise ratio of the multiplexed signal satisfies a predetermined criterion, the multiplexed signal includes the first modulation symbol sequence as an undetermined signal component. The second bit likelihood sequence is generated by demapping the multiplexed signal, and the first modulation symbol sequence is subtracted when the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion. Further, the second bit likelihood sequence may be generated by demapping the multiplexed signal.

  Thereby, the receiving apparatus can suppress the processing delay that occurs in the sequential decoding in the combination of the sequential decoding and the parallel decoding.

  In addition, for example, the multiplexed signal received by the receiving unit includes the first modulation symbol sequence generated by mapping the first bit sequence of the first data sequence, and the second data sequence. And a second modulation symbol sequence generated by mapping the second bit sequence of the first modulation symbol sequence with a predetermined amplitude ratio, and a real part and an imaginary number of each modulation symbol in the second modulation symbol sequence The polarity of the part may be a signal controlled according to the first modulation symbol string.

  As a result, the receiving apparatus can receive, as a multiplexed signal, a signal in which the first modulation symbol and the second modulation symbol whose polarity is inverted in accordance with the first modulation symbol are superimposed. By reversing the polarity of the second modulation symbol, a plurality of signal points associated with the same bit group of the second data series are brought closer. Therefore, the receiving apparatus can receive the multiplexed signal adjusted so that the second modulation symbol sequence is appropriately generated, and can perform efficient processing.

  In addition, the reception method according to an aspect of the present disclosure is a signal in which a plurality of data sequences including a first data sequence of the first layer and a second data sequence of the second layer are multiplexed by superposition coding. A reception method for receiving a multiplexed signal, wherein the multiplexed signal is received, and the multiplexed signal is demapped, whereby a first data portion corresponding to the first data sequence and a first error control A first bit likelihood sequence including a portion and error control decoding is performed on the first bit likelihood sequence, and the error corrected first data portion and the error corrected A first bit string including the first error control part is derived, and the first bit string including the error-corrected first data part and the error-corrected first error control part is obtained. By mapping, the first Generating a key symbol sequence, delaying the received multiplexed signal, subtracting the first modulation symbol sequence from the delayed multiplexed signal, and subtracting the first modulation symbol sequence from the multiplexed signal Is de-mapped to generate a second bit likelihood sequence including a second data portion corresponding to the second data series and a second error control portion, and the second bit likelihood By performing error control decoding on the column, the second data series including the second data portion subjected to error correction is derived.

  As a result, the reception device or the like using this reception method generates the first modulation symbol string of the first data sequence without encoding the first data sequence by the reception device or the like, and generates the generated first The second data series can be acquired using the modulation symbol sequence. Therefore, a receiving apparatus using this receiving method can suppress processing delay. In other words, a receiving apparatus or the like using this receiving method can perform efficient processing with respect to a multiplexing scheme using superposition coding.

  For example, the reception method further derives the first data sequence including the error-corrected and deinterleaved first data portion by deinterleaving the error-corrected first data portion. May be.

  Thereby, a receiving apparatus or the like using this receiving method can perform error control decoding before deinterleaving. Therefore, a reception device or the like using this reception method can further reduce the time for generating the first modulation symbol sequence in the reception device or the like, and can suppress processing delay.

  In addition, for example, the reception method further deinterleaves the first bit likelihood sequence generated by demapping the multiplexed signal, and in deriving the first bit sequence, the deinterleaved The first bit sequence is derived by performing error control decoding on the first bit likelihood sequence, and the reception method further interleaves the derived first bit sequence, In generating the modulation symbol sequence, the first modulation symbol sequence may be generated by mapping the interleaved first bit sequence.

  As a result, a receiving apparatus or the like using this receiving method can perform error control decoding after deinterleaving. Therefore, a receiving apparatus or the like using this receiving method can perform error control decoding after rearranging the bit likelihood sequences in an order suitable for error control decoding.

  For example, in the generation of the second bit likelihood sequence, when the signal-to-noise ratio of the multiplexed signal satisfies a predetermined criterion, the multiplexed signal uses the first modulation symbol sequence as an undefined signal component. And including the first modulation symbol sequence when the second bit likelihood sequence is generated by demapping the multiplexed signal and the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion. The second bit likelihood sequence may be generated by demapping the multiplexed signal from which is subtracted.

  Thereby, the receiving apparatus etc. which use this receiving method can suppress the processing delay which generate | occur | produces in sequential decoding in the combination of sequential decoding and parallel decoding.

  Further, for example, the multiplexed signal includes the first modulation symbol sequence generated by mapping the first bit sequence of the first data sequence, and the second bit sequence of the second data sequence. The second modulation symbol sequence generated by mapping is superimposed on the signal at a predetermined amplitude ratio, and the polarities of the real part and the imaginary part of each modulation symbol in the second modulation symbol sequence are It may be a signal controlled according to one modulation symbol string.

  As a result, a reception apparatus or the like using this reception method receives, as a multiplexed signal, a signal in which the first modulation symbol and the second modulation symbol whose polarity is inverted in accordance with the first modulation symbol are superimposed. be able to. By reversing the polarity of the second modulation symbol, a plurality of signal points associated with the same bit group of the second data series are brought closer. Therefore, a receiving apparatus or the like using this receiving method can receive the multiplexed signal adjusted so that the second modulation symbol sequence is appropriately generated, and can perform efficient processing.

  In the description of each embodiment described above, for the sake of simplicity, an example has been described in which two data sequences are multiplexed and transmitted in two layers, but three or more data sequences are multiplexed and transmitted. Obviously, the transmission can be easily expanded according to the embodiment.

  1 and 13 to 15 show an example in which the transmission apparatus does not include an antenna, and a signal in a radio frequency band is transmitted from an external antenna connected to the transmission apparatus. However, the transmission device may include an antenna, and a signal in a radio frequency band may be transmitted from the antenna of the transmission device.

  2, 7, 16 to 19, 24, 28 to 32, and 35 to 38, the receiving apparatus does not include an antenna, and a signal in a radio frequency band is transmitted from an external antenna connected to the receiving apparatus. Is shown. However, the receiving apparatus may include an antenna, and a radio frequency band signal may be received by the antenna of the receiving apparatus.

  The antenna used for transmitting or receiving a radio frequency band signal may be an antenna unit including a plurality of antennas.

  Although not shown in FIGS. 1 and 13 to 15, the transmission apparatus generates a frame by arranging the superimposed signal generated by the addition unit according to a predetermined frame configuration, and transmits the frame to the RF unit. May be provided.

  Here, the configuration of the frame generated by the frame configuration unit may be fixed, or may be changed according to a control signal transmitted from a control unit (not shown). The frame configuration unit arranges a superimposed modulation symbol sequence in which the first data sequence and the second data sequence are multiplexed in a frame according to a predetermined rule.

  In addition, the frame generated by the frame configuration unit may include pilot symbols, control information symbols, preambles, and the like in addition to data symbols. Each of the pilot symbol, the control information symbol, and the preamble may be called with a different name.

  For example, the pilot symbol may be a symbol generated by performing a mapping process based on a PSK modulation such as BPSK and QPSK on a bit string known to the receiving apparatus. The pilot symbol may be a symbol having a known amplitude and phase (or a known complex value) for the receiving apparatus. The pilot symbol may also be a symbol that allows the receiving apparatus to estimate the amplitude and phase (or complex value) transmitted by the transmitting apparatus.

  Then, the reception apparatus performs frequency synchronization, time synchronization, channel estimation, and the like on the received signal using pilot symbols. Channel estimation is also referred to as CSI (Channel State Information) estimation.

  The control information symbol is a symbol used for transmission of information to be notified to the receiving apparatus as information for demodulating the received signal to obtain a desired data sequence.

  For example, the transmission apparatus transmits a control information symbol corresponding to the control information. In the control information, the mapping (modulation) method used for each data sequence, the error control coding method, the coding rate and code length of the error control coding method, and the modulation symbol of the data sequence are arranged in a frame. The position or the like may be indicated. The receiving apparatus demodulates the control information symbol to obtain control information. Then, the receiving apparatus demodulates the data symbols based on the acquired control information, and acquires a data series.

  The control information may include setting information in an upper layer that controls the operation of the application.

  The preamble is a signal added to the head of the frame. The receiving apparatus may receive a signal including a preamble and perform, for example, frame detection and frame synchronization processing based on the preamble. The preamble may include a pilot symbol and a control information symbol. Further, the frame may include not only the preamble but also a postamble that is a signal added to the rear end of the frame.

  The encoding unit uses, for example, an LDPC (Low Density Parity Check) code or a turbo code as an error control encoding method. The encoding unit may use other encoding methods.

  1 and 13 to 15 include an interleaving unit, the transmission device may not include an interleaving unit as described above. In that case, the transmission apparatus may directly input the bit string generated by the encoding unit to the mapping unit, or may input the bit sequence generated by the processing different from the interleaving to the mapping unit. In addition, when the transmission device does not include the interleaving unit, the reception devices illustrated in FIGS. 2, 7, 16 to 19, 24, 28 to 32, and 35 to 38 may not include the deinterleaving unit.

  2, 16, 19 to 19, 24, 28 to 32, and 35 to 38, the deinterleaving unit performs rearrangement based on the rearrangement rule opposite to the rearrangement rule performed on the transmission side. However, an operation different from such rearrangement may be performed. For example, the deinterleaving unit may input a plurality of bit likelihoods of the bit likelihood sequence generated by the demapping unit to the decoding unit in the bit order required in the decoding process performed by the decoding unit.

  In the above, superposition coding and modified superposition coding are applied to wireless transmission. However, the present invention may be applied not only to wireless transmission but also to wired transmission or optical transmission, and is applicable to recording on a recording medium. May be. Further, the frequency band used for transmission is not limited to the radio frequency band, and may be a baseband.

  In the above description, an error-corrected bit string or the like means a bit string or the like in which an error is corrected when an error exists.

  Further, “plurality” used in the present disclosure is synonymous with “two or more”. In addition, the ordinal numbers such as the first, second, and third may be appropriately removed in terms of expression, may be replaced, or may be newly added.

  In addition, the apparatus and method in the present disclosure are not limited to the respective embodiments, and can be implemented with various modifications. For example, in each embodiment, the technology of the present disclosure is realized as a communication device (a transmission device or a reception device), but the technology of the present disclosure is not limited to this. The technology of the present disclosure may be realized as software for executing a communication method (transmission method or reception method) performed by the communication device.

  Further, two or more components in the transmission device or the reception device may be integrated into one component, or one component may be divided into two or more components. Further, the transmission device and the reception device may constitute one transmission / reception device. In this case, a plurality of components of the same type may be integrated into one component. For example, the transmission antenna and the reception antenna may be configured by one antenna.

  Further, for example, another component may execute a process executed by a specific component. In addition, the order in which the processes are executed may be changed, or a plurality of processes may be executed in parallel.

  Further, for example, a program for executing the communication method may be stored in advance in a ROM (Read Only Memory), and the program may be executed by a CPU (Central Processor Unit).

  A program for executing the communication method may be stored in a computer-readable storage medium. Then, the program stored in the storage medium may be recorded in a RAM (Random Access Memory) of the computer, and the computer may execute the communication method according to the program.

  Each component in the above-described embodiments may be realized as an LSI (Large Scale Integration) which is a typical integrated circuit. Each component may be individually made into one chip, or all or some of the components in each embodiment may be made into one chip. Although an LSI is illustrated here, such an integrated circuit may be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

  The method of circuit integration is not limited to LSI. Each component may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection or setting of circuit cells inside the LSI may be used.

  Furthermore, if integrated circuit technology that replaces LSI appears as a result of advances in semiconductor technology or other derived technology, it is natural that the device described in each embodiment or a part of the configuration can be integrated using the technology. It may be done. For example, biotechnology can be applied.

  The present disclosure can be widely applied to a wireless system that transmits different modulated signals (multiplexed signals) from a plurality of antennas. The present disclosure can also be applied to MIMO (Multiple Input Multiple Output) transmission in a wired communication system having a plurality of transmission locations. Examples of such a wired communication system include a PLC (Power Line Communication) system, an optical communication system, and a DSL (Digital Subscriber Line) system.

  The present disclosure can be applied to a wireless communication system, a broadcasting system, and the like. Further, the present disclosure can be widely applied to a system that multiplexes a plurality of data sequences using superposition coding.

  The present disclosure can also be applied to, for example, a wired communication system such as a PLC (Power Line Communication) system, an optical communication system, and a DSL (Digital Subscriber Line) system. The present disclosure can also be applied to a storage system that performs recording on a recording medium such as an optical disk and a magnetic disk.

100, 500, 600, 700 Transmitting device 111, 121, 214, 414, 511, 521, 611, 621, 711, 721, 814, 914, 1014 Encoding unit 112, 122, 215, 415, 512, 522, 612 , 622, 712, 722, 815, 915, 1015, 1215, 1315, 1415, 1515, 1615 Interleaving section 113, 123, 216, 416, 513, 523, 613, 623, 713, 723, 816, 916, 1016, 1216, 1316, 1416, 1516, 1616, 1716, 1816, 1916, 2016, 2116 Mapping unit 114, 124, 217, 417, 514, 524, 614, 624, 714, 724, 817, 917, 1017, 1217, 1317 , 417, 1517, 1617, 1717, 1817, 1917, 2017, 2117 Multiplier 130, 530, 630, 730 Adder 140, 230, 330, 430, 540, 640, 740, 830, 930, 1030, 1130, 1230, 1330, 1430, 1530, 1630, 1730, 1830, 1930, 2030, 2130 RF section (Radio Frequency section)
200, 300, 400, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100 Receiver 211, 221, 310, 411, 421, 811, 821, 911 921, 1011, 1021, 1110, 1211, 1221, 1311, 1321, 1411, 1421, 1511, 1521, 1611, 1621, 1711, 1721, 1811, 1821, 1911, 1921, 2011, 2021, 2111, 2121 Demapping Part 212, 222, 312, 322, 412, 422, 812, 822, 912, 922, 1012, 1022, 1112, 1122, 1212, 1222, 1312, 1322, 1412, 1422, 15 12, 1522, 1612, 1622, 1712, 1722, 1812, 1822, 1912, 1922, 2012, 2022, 2112, 2122 Deinterleave unit 213, 223, 313, 323, 413, 423, 813, 823, 913, 923, 1013, 1023, 1113, 1123, 1213, 1223, 1313, 1323, 1413, 1423, 1513, 1523, 1613, 1623, 1713, 1723, 1813, 1823, 1913, 1923, 2013, 2023, 2113, 2123 Decoding unit 218 418, 818, 918, 1018, 1218, 1318, 1418, 1518, 1618, 1718, 1818, 1918, 2018, 2118 delay unit 219, 419, 819, 919, 1019, 219,1319,1419,1519,1619,1719,1819,1919,2019,2119 subtraction unit 525,625,820,920,1420,1520,1920,2020 conversion unit

Claims (10)

A receiving apparatus that receives a multiplexed signal that is a signal in which a plurality of data sequences including a first data sequence of a first hierarchy and a second data sequence of a second hierarchy are multiplexed by superposition coding,
A receiver for receiving the multiplexed signal;
A first demapping that generates a first bit likelihood sequence including a first data portion corresponding to the first data sequence and a first error control portion by demapping the multiplexed signal. And
By performing error control decoding on the first bit likelihood sequence, a first bit sequence including the error-corrected first data portion and the error-corrected first error control portion is obtained. A first decoding unit to derive;
A mapping unit that generates a first modulation symbol sequence by mapping the first bit sequence including the error-corrected first data portion and the error-corrected first error control portion;
A delay unit for delaying the multiplexed signal received by the receiving unit;
A subtractor for subtracting the first modulation symbol sequence from the multiplexed signal delayed by the delay unit;
A second bit including a second data portion corresponding to the second data sequence and a second error control portion by demapping the multiplexed signal from which the first modulation symbol sequence has been subtracted. A second demapping unit for generating a likelihood sequence;
And a second decoding unit for deriving the second data sequence including the second data portion subjected to error correction by performing error control decoding on the second bit likelihood sequence. . The receiver further deinterleaves the first data sequence including the error-corrected and deinterleaved first data portion by deinterleaving the error-corrected first data portion. The receiving device according to claim 1. The receiving apparatus further includes a deinterleaving unit that deinterleaves the first bit likelihood sequence generated by demapping the multiplexed signal,
The first decoding unit derives the first bit sequence by performing error control decoding on the first bit likelihood sequence that has been deinterleaved,
The receiving apparatus further includes an interleaving unit that interleaves the derived first bit string.
The receiving apparatus according to claim 1, wherein the mapping unit generates the first modulation symbol sequence by mapping the interleaved first bit sequence. The second demapping unit includes:
When the signal-to-noise ratio of the multiplex signal satisfies a predetermined criterion, the multiplex signal is demapped in a state where the multiplex signal includes the first modulation symbol sequence as an undetermined signal component. Generate a bit likelihood sequence of 2;
When the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion, the second bit likelihood sequence is generated by demapping the multiplexed signal from which the first modulation symbol sequence is subtracted. Item 4. The receiving device according to any one of Items 1 to 3. The multiplexed signal received by the receiving unit includes the first modulation symbol sequence generated by mapping the first bit sequence of the first data sequence, and the second modulation sequence of the second data sequence. A signal in which a second modulation symbol sequence generated by mapping the bit sequence is superimposed at a predetermined amplitude ratio, and the polarities of the real part and the imaginary part of each modulation symbol in the second modulation symbol sequence are The receiving apparatus according to claim 1, wherein the receiving apparatus is a signal controlled in accordance with the first modulation symbol string. A reception method for receiving a multiplexed signal that is a signal in which a plurality of data sequences including a first data sequence of a first hierarchy and a second data sequence of a second hierarchy are multiplexed by superposition coding,
Receiving the multiplexed signal;
Generating a first bit likelihood sequence including a first data portion corresponding to the first data sequence and a first error control portion by demapping the multiplexed signal;
By performing error control decoding on the first bit likelihood sequence, a first bit sequence including the error-corrected first data portion and the error-corrected first error control portion is obtained. Derived,
Mapping the first bit sequence including the error-corrected first data portion and the error-corrected first error control portion to generate a first modulation symbol sequence;
Delay the received multiplexed signal;
Subtracting the first modulation symbol sequence from the delayed multiplexed signal;
A second bit including a second data portion corresponding to the second data sequence and a second error control portion by demapping the multiplexed signal from which the first modulation symbol sequence has been subtracted. Generate a likelihood sequence,
A receiving method for deriving the second data sequence including the second data portion subjected to error correction by performing error control decoding on the second bit likelihood sequence. The reception method further derives the first data sequence including the first data part subjected to error correction and deinterleaving by deinterleaving the first data part subjected to error correction. 6. The receiving method according to 6. The reception method further includes deinterleaving the first bit likelihood sequence generated by demapping the multiplexed signal,
In deriving the first bit sequence, error control decoding is performed on the first bit likelihood sequence that has been deinterleaved to derive the first bit sequence,
The reception method further interleaves the derived first bit string,
The reception method according to claim 6, wherein in the generation of the first modulation symbol sequence, the first modulation symbol sequence is generated by mapping the interleaved first bit sequence. In the generation of the second bit likelihood sequence,
When the signal-to-noise ratio of the multiplex signal satisfies a predetermined criterion, the multiplex signal is demapped in a state where the multiplex signal includes the first modulation symbol sequence as an undetermined signal component. Generate a bit likelihood sequence of 2;
When the signal-to-noise ratio of the multiplexed signal does not satisfy a predetermined criterion, the second bit likelihood sequence is generated by demapping the multiplexed signal from which the first modulation symbol sequence is subtracted. Item 9. The reception method according to any one of Items 6 to 8. The multiplexed signal is obtained by mapping the first modulation symbol sequence generated by mapping the first bit sequence of the first data sequence and the second bit sequence of the second data sequence. A signal in which the generated second modulation symbol sequence is superimposed at a predetermined amplitude ratio, and the polarities of the real part and imaginary part of each modulation symbol in the second modulation symbol sequence are the first modulation symbols The reception method according to any one of claims 6 to 9, wherein the signal is controlled according to a column.

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