JP5773530B2 - Communication apparatus, communication system, and digital modulation / demodulation method - Google Patents

Description

  The present invention relates to a communication apparatus, a communication system, and a communication method that communicate with signals using a plurality of orthogonal transmission paths.

  In general, a signal representing information is represented as a baseband signal having a finite band due to band limitation. Therefore, a signal modulated using this is usually a band signal having a finite band centered on the carrier frequency fc. Such band signals are represented by baseband signals called in-phase (I) signals and quadrature (Q) signals.

  In the field of digital modulation / demodulation, as the demand for mobile communications increases, it becomes necessary to effectively use frequency resources (frequency utilization efficiency), and signal points represented by a complex plane (IQ plane). Multi-value processing has been promoted.

  Furthermore, in recent years, for example, in the field of wireless communication, due to the widespread use of wireless communication systems, a shortage of frequency resources has become apparent, especially in the microwave band, and transmission techniques for achieving higher frequency utilization efficiency are demanded. It has been. In particular, there is a tendency to achieve such high frequency use efficiency in an environment that is affected by fading due to multipath such as an urban area.

  Also, in the field of optical communication, etc., the capacity of digital optical transmission systems is being increased. However, as the capacity of a digital optical transmission system increases, the amount of light allocated to one symbol decreases, making it difficult to ensure desired communication quality. For this reason, there is a demand for an optical transmission system that has high reception sensitivity and can ensure desired communication quality. In addition, if the configuration of the transmitter / receiver is complicated in order to increase the reception sensitivity and ensure high signal quality, the cost merit due to the increase in capacity is offset.

  In order to improve the utilization efficiency of the transmission path, conventionally, in the communication field, frequency division multiplexing (FDM), time division multiplexing (TDM), code division multiplexing (CDM) is used. ), So-called multiplexing techniques such as space division multiplexing (SDM), and multiple access techniques have been developed. Furthermore, in optical communication, techniques such as wavelength division multiplexing (WDM) are also used.

  Furthermore, in recent years, for example, in the field of wireless communication, a technique called orthogonal frequency division multiplexing (OFDM) using a plurality of orthogonal subcarriers (OFDM) (see Patent Document 1), orthogonal polarization, A technique called a wave multiplexing technique is used. The orthogonal polarization multiplexing technology pays attention to the wavefront direction of radio waves radiated from an antenna and transmits independent signals having wavefronts orthogonal to each other at the same frequency (Patent Document 2, Non-Patent Document 1, Non-Patent Document). Reference 2). Such orthogonal polarization multiplexing technology is also used in the field of optical communications.

  In particular, in order to efficiently perform multiplexing on the same physical transmission line, one logical transmission line in a plurality of logical transmission lines to be multiplexed (hereinafter referred to as “logical transmission line”). Therefore, it is necessary that the signals transmitted through the network do not interfere with the signals transmitted through other logical transmission paths. For this reason, it is desirable that the logical transmission paths are so-called “orthogonalized” with each other. . The above-described OFDM technology and orthogonal polarization multiplexing technology use such orthogonal logical transmission paths (hereinafter referred to as “orthogonal logical transmission paths”).

JP2011-217231A JP 2007-189306 A

Yamashita, F .; kobayasi, K .; Ueba, M .; Takeda, Y .; Ando, K. , “Variable Polarization / Frequency Division Multiplexing (VPDFM) for Satellite Communications,” IEEE VTC2006-Fall, pp.1-5 Yoshinori Suzuki, Fumihiro Yamashita, Kiyoshi Kobayashi, Yozo Takeda, “Digitally Controlled Polarization Tracking Antenna in Ku vs. Mobile Satellite Communications”, IEICE, 2010 IEICE Technical Report, A / P2010-54, SAT2010- 15 (2010-07) pp. 93-98

  However, in actual signal transmission, noise from the transmission path is mixed, and there is also the influence of fading as described above. Therefore, when decoding a signal received on the receiving side, a decoding error probability is set. A decoding method that can be reduced is desired.

As such a decoding method, it is a determination method that “determines that the code word x ⁿ that maximizes Q (y ⁿ | x ⁿ ) with respect to the received word y ⁿ is a code word that has been sent”. A “likelihood decoding method” is known. Here, the conditional probability Q (y | x) of the communication channel is “the likelihood of the codeword x when the received word y is received”.

  However, as described above, as the number of signal points on the IQ plane increases, the amount of computation for maximum likelihood decoding increases exponentially.

  Therefore, a communication method that can suppress the processing load of the transceiver while improving the frequency utilization efficiency is desired.

  In addition, as mentioned above, the quality of the transmission path deteriorates with increasing capacity, or the state of the transmission path changes with time due to fading as in mobile communications. is necessary.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve a frequency utilization efficiency and a data transmission speed by multiplex communication, It is to provide a communication system and a communication method.

  Another object of the present invention is to provide a communication device, a communication system, and a communication method that can cope with a change in communication quality of a transmission line when data transmission is performed by multiplex communication.

  According to an aspect of the present invention, there is provided a communication device for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other, wherein a partial bit string constituting a transmission bit string is a first corresponding to a predetermined modulation scheme. Encoding means for converting to n (n: natural number) transmission primary symbols respectively corresponding to the first signal points on the constellation of the second constellation, and the n transmission primary symbols on the second constellation. Each of the second signal points in at least one transmission secondary symbol is provided with conversion means for converting into m transmission (m: natural number) transmission secondary symbols smaller than n transmissions, each corresponding to two signal points. Corresponds to a plurality of predetermined types of transmission bit strings which are degenerate and further correspond to transmission modulation means for transmitting m transmission secondary symbols for transmission through a plurality of orthogonal transmission paths. Provided.

  Preferably, the conversion unit includes m transmission primary symbols as principal components of the n transmission primary symbols, and the remaining (nm) transmission primary symbols are applied to the principal components. On the other hand, the transmission primary symbol is transmitted assuming that it is arranged at the signal point of the quadrature amplitude modulation on the second constellation by superimposing each of the m transmission primary symbols by hierarchizing to reduce the amplitude sequentially. Convert to secondary symbol.

  Preferably, when the ratio of n systems to m systems is a multiplicity, the converting means changes the multiplicity according to the quality of the transmission paths of the plurality of orthogonal transmission paths, so that the number of transmission primary symbol systems Alternatively, multiplicity changing means for changing the number of transmission secondary symbol systems is further provided.

  According to another aspect of the present invention, there is provided a communication device for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other, and performing demodulation processing on signals received from the plurality of orthogonal transmission paths In each of the reception means for demodulating the received signal corresponding to the transmitted secondary symbol and the mapping of the signal space diagram, the likelihood is calculated for the received signal and the signal point corresponding to the transmitted secondary symbol, and the most probable symbol And a likelihood determining means for calculating a transmission primary symbol corresponding to the specified transmission secondary symbol, and the transmission primary symbol constitutes a transmission bit string on the transmission side. The partial bit string is converted so as to correspond to the first signal points of the n systems on the first constellation corresponding to the predetermined modulation method. The transmission secondary symbols are converted from the n transmission primary symbols into m transmission secondary symbols that are fewer than the n transmissions corresponding to the second signal points on the second constellation. Each of the second signal points in at least one transmission secondary symbol corresponds to a plurality of predetermined transmission bit sequences that are degenerate, and the transmission primary symbol calculated by the likelihood determination means Is further provided with decoding means for converting the data into a corresponding bit string.

  Preferably, the mapping of the signal space diagram in the likelihood calculation of the likelihood determining means has m transmission primary symbols as principal components among the n transmission primary symbols, and the remaining (n−m) systems. For the transmission primary symbols, the quadrature amplitude modulation signal on the second constellation is superposed on each of the m transmission primary symbols by hierarchization in which the amplitude is sequentially reduced with respect to each principal component. Assuming that the transmission primary symbol is arranged at the point, it corresponds to the transmission primary symbol converted into the transmission secondary symbol.

  Preferably, when the ratio of n systems to m systems is multiplicity, on the transmission side, the multiplicity is changed according to the quality of the transmission paths of a plurality of orthogonal transmission paths, whereby the number of transmission primary symbol systems Or in order to change the number of systems of the transmission secondary symbol, it further comprises means for transmitting information on the quality of the transmission path to the transmission side.

  According to still another aspect of the present invention, there is provided a communication system for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other, comprising a transmission device, and the transmission device is a portion constituting a transmission bit string Coding means for converting the bit string into n transmission (n: natural number) transmission primary symbols respectively corresponding to the first signal points on the first constellation corresponding to a predetermined modulation scheme, and n transmissions 1 Conversion means for converting the next symbol into m secondary (m: natural number) transmission secondary symbols respectively corresponding to the second signal points on the second constellation, and having at least one Each of the second signal points in the transmission secondary symbol corresponds to a plurality of predetermined types of transmission bit strings, and m transmission secondary symbols are respectively transmitted by a plurality of orthogonal transmission paths. It further includes transmission modulation means for transmission for transmission, and further includes a reception device. The reception device performs demodulation processing on the received signals from the plurality of orthogonal transmission paths, and each corresponds to a transmission secondary symbol. In the mapping of the receiving means for demodulating the received signal and the signal space diagram, the likelihood is calculated for the signal point corresponding to the transmitted secondary symbol for the received signal, and the most probable symbol is identified and identified. Likelihood determining means for calculating a transmission primary symbol corresponding to the transmitted secondary symbol, and decoding means for converting the transmission primary symbol calculated by the likelihood determining means into a corresponding bit string.

  According to still another aspect of the present invention, there is provided a communication method for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other, wherein a partial bit sequence constituting a transmission bit sequence is defined on a transmission side by a predetermined bit sequence. A step of converting into n primary (n: natural number) transmission primary symbols respectively corresponding to the first signal points on the first constellation corresponding to the modulation method; And a step of converting to m secondary (m: natural number) transmission secondary symbols each corresponding to the second signal point on the second constellation, and having at least one transmission secondary symbol Each of the second signal points in FIG. 1 corresponds to a plurality of predetermined transmission bit sequences that are degenerate, so that m transmission secondary symbols are transmitted through a plurality of orthogonal transmission paths, respectively. Further comprising a step of performing a demodulation process on the received signals from the plurality of orthogonal transmission paths on the receiving side, and demodulating each of the received signals corresponding to the transmission secondary symbols; In the mapping of the signal space diagram, the likelihood is calculated for the signal point corresponding to the transmitted secondary symbol for the received signal, the most likely symbol is identified as the received symbol, and the transmission corresponding to the identified transmitted secondary symbol is performed. The method further includes a step of calculating a primary symbol, and a step of converting the calculated transmission primary symbol into a corresponding bit string on the receiving side.

  According to the present invention, it is possible to improve the frequency utilization efficiency and the data transmission speed by multiplex communication.

  Further, according to the present invention, it is possible to cope with a change in communication quality of a transmission path when data transmission is performed by multiplex communication.

  Furthermore, according to the present invention, information consisting of a bit string is distributed and transmitted in a plurality of orthogonal transmission paths while having various degenerate relationships with each other, making it difficult for a third party who does not know the degenerate relationship to intercept. It is possible.

It is a conceptual diagram for demonstrating the structure of a radio | wireless communications system. It is a conceptual diagram for demonstrating the structure of the modification of a radio | wireless communications system. FIG. 10 is a diagram for explaining a configuration of still another modification of the wireless communication system. FIG. 10 is a diagram for explaining a configuration of still another modification of the wireless communication system. FIG. 10 is a diagram for explaining a configuration of still another modification of the wireless communication system. 3 is a diagram showing an arrangement of the constellation of the corresponding signal points transmitted primary symbol M ₁ ~M ₃ strains. Data number of the transmission secondary symbols S ₁ to S ₂ of two systems and a value indicating a binary bit representation illustrates a table. It is a diagram showing the relationship between the signal point of the signal point and S ₂ components of S ₁ component in the example shown in FIG. FIG. 8 is another diagram showing the relationship between the S ₁ component signal point and the S ₂ component signal point in the example shown in FIG. 7. It is a conceptual diagram which shows the signal point arrangement | positioning procedure of a multiplexed signal. It is a figure which shows the constellation arrangement | positioning of a transmission primary symbol. It is a diagram showing a signal point numbers for each of the transmit secondary symbols S ₁ to S _3. Is a diagram for explaining a combination of transmission primary symbol M ₁ ~M ₄ corresponding to the signal point number of the transmission secondary symbols S ₁ to S _3. It is a figure for demonstrating the structure of the radio | wireless communications system for performing the secondary hierarchization of a transmission signal point. It is a figure which shows the signal point arrangement | positioning on the constellation of the multiplexed signal after the hierarchization by the structure shown in FIG. It is a figure which shows the relationship between the signal point number with respect to the signal point arrangement | positioning shown in FIG. 15, and the corresponding transmission primary symbol. It is a figure for demonstrating the structure of the radio | wireless communications system which uses a polarization multiplexing modulation system as an orthogonal transmission line. FIG. 10 is a diagram for explaining a configuration of still another modification of the wireless communication system. 7 is a block diagram for illustrating a configuration of a wireless communication system according to a third embodiment. FIG. 10 is a block diagram for illustrating a configuration of a wireless communication system according to a fourth embodiment. FIG.

  Hereinafter, a radio communication system according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, components and processing steps given the same reference numerals are the same or equivalent, and the description thereof will not be repeated unless necessary.

  In the following example, wireless communication will be described as an example. However, the present invention is not limited to this, and can be applied to other techniques using digital modulation / demodulation such as optical communication.

  In the following description, “constellation” refers to the entire signal arrangement when mapping a complex transmission signal on an IQ plane corresponding to a specific modulation scheme, and “signal point” refers to Refers to the coordinate position on the IQ plane of each complex transmission signal arranged on the constellation. A “symbol” is a “code” that is a unit of information that is modulated on the transmission side and transmitted by a reference clock. ", Which corresponds to one of the signal points on the constellation.

(Concept of transmitter and receiver configuration)
FIG. 1 is a conceptual diagram for explaining a configuration of a wireless communication system.

  The wireless communication system shown in FIG. 1 includes a wireless transmitter 1000 and a wireless receiver 2000. Here, for convenience of explanation, the transmitter and the receiver are described as separate devices, but one device may have the functions of the transmitter and the receiver.

Referring to FIG. 1, a wireless transmitter 1000 encodes a digital signal to be transmitted and encodes / assigns a plurality of transmission bit strings D _{1 to} D _n (n: natural number), Modulators 102-1 to 102-n that modulate a plurality of transmission bit strings D _{1 to} D _n with the corresponding modulation schemes to modulate (primary modulation) transmission symbols M, respectively. Here, each of the “transmission bit sequences D _{1 to} D _n ” includes a predetermined number of bits, and the “modulation scheme” is a scheme for modulating such a transmission bit sequence by discontinuous changes in amplitude and phase. For example, it means QPSK (Quadrature Phase Shift Keying) of a phase shift keying modulation system that modulates 2 bits as one symbol.

The wireless transmitter 1000 further converts the n transmission primary symbols from the modulators 102-1 to 102-n into m transmission (m: natural number) secondary symbols S ₁ to S ₁ through the procedure described below. Mapping conversion section 104 that converts to S _m , and transmission modulator 106 that performs secondary modulation in order to send transmission secondary symbols S _{1 to} S _m to the orthogonal transmission path, respectively.

Here, mapper 104 performs a "mapping _{conversion", M = {M 1, M} 2, ..., M n}, S = {S 1, S 2, ..., S n} when a, This means that the output vector S is output by the conversion S = f (M) for the input vector M. However, n> m and the function f (M) is injective. “Injection” refers to a mapping in which any element belonging to the range is represented as a single original image of the domain. As will be described later, at least one element (transmission secondary symbol) Si among the elements of the output vector corresponds to a set of two or more input vectors (M _j , M _k ,...). In this sense, a signal point corresponding to the transmission secondary symbol is referred to as “degenerate”. However, since it is injective, on the receiving side, an inverse function f ⁻¹ (...) Can be defined in advance for a signal point corresponding to a predetermined secondary symbol, and f ⁻¹ (S _i ) , (M _j , M _k ,...) Can be uniquely identified.

  The term “orthogonal transmission path” refers to a transmission path in which a signal transmitted through one transmission path does not in principle interfere with a signal transmitted through another transmission path. It does not matter whether a plurality of signals are transmitted synchronously or asynchronously, including not only when the transmission paths are orthogonal but also when each transmission path is physically independent. For example, frequency division multiplexing in which the bands are separated so as not to interfere with each other may be used, or even if the bands overlap, an orthogonal frequency division multiplexing system in which subcarriers are configured to be orthogonal to each other may be used. Further, it may have a plurality of logical transmission paths capable of independently transmitting signals by so-called time division multiplexing or code division multiplexing. Therefore, for example, transmission paths that do not interfere with each other and are transmitted by a multiplexing method such as packet multiplexing or frame multiplexing may be used.

Referring to FIG. 1, radio receiver 2000 performs a secondary demodulation of a signal received from an orthogonal transmission path and separates it into secondary reception symbols S _{1 to} S _m , and a secondary reception. Maximum likelihood decoding (MLD: Maximum Likelihood Detection) is applied to symbols S _{1 to} S _m , and the maximum likelihood is converted into a plurality of received bit strings D _{1 to} D _n by a procedure that performs a reverse mapping to the transmission side. It includes a determination unit 202 and a decoding / bit conversion processing unit 204 that performs decoding and bit conversion processing on the received bit strings D _{1 to} D _n and outputs received signal bits.

  Here, although not particularly limited, for example, the maximum likelihood determiner 202 executes the following procedure.

  First, the maximum likelihood determiner 202 calculates a metric such as a square Euclidean distance for a combination of a received signal and a symbol replica of a transmission signal generated from all candidate points assumed as a transmission signal. The likelihood of the transmission signal is calculated. Then, the maximum likelihood determiner 202 determines the symbol replica having the highest likelihood as the transmission secondary symbol of the original transmission signal. Furthermore, the maximum likelihood determiner 202 finally extracts a transmission bit string by identifying the transmission primary symbol from the identified transmission secondary symbol by the inverse transformation described above.

  Such inverse transformation will be described later.

(Modification of the concept of the transmitter and receiver configuration)
FIG. 2 is a conceptual diagram for explaining a configuration of a modification of the wireless communication system.

  Even with the configuration of the wireless communication system as shown in FIG. 2, it is possible to realize substantially the same operation as the wireless communication system shown in FIG.

  The configuration of the modification of the radio communication system shown in FIG. 2 is different from the configuration of the radio communication system shown in FIG. Will not repeat.

Referring to FIG. 2, radio transmitter 1000 encodes a digital signal to be transmitted and encodes / assigns processor 100 that divides the digital signal into a plurality of transmission bit sequences D _{1 to} D _n (n: natural number); a storage unit 103-1 to 103-n for storing a plurality of transmit bit sequence D ₁ to D _n, respectively, from the data stored in the storage unit 103-1 to 103-n, the modulation (primary modulation with corresponding modulation scheme ) The transmission primary symbol data corresponding to the n system signal points on the constellation corresponding to the constellation correspond to the m system (m: natural number) signal points on the constellation by the procedure described later. a mapping processing unit 105 for converting the transmitting secondary symbols S ₁ to S _m, transmit modulator transmit secondary symbols S ₁ to S _m, to primary modulation and secondary modulation for delivery to the respective orthogonal channels 10 7 and the like.

  FIG. 3 is a diagram for explaining a configuration of still another modification of the wireless communication system.

  In FIG. 3, the well-known RF front end is not shown.

  In FIG. 3, as an example of the orthogonal transmission path, a configuration is shown in which information can be independently transmitted through, for example, m systems (m: natural number) of logical transmission paths using the orthogonal frequency division multiplexing method.

That is, the transmitter 1000 encodes the transmission bit strings D _{1 to} D _n to be transmitted and converts them into transmission primary symbols, and the transmission primary symbols to m systems of transmission secondary symbols S ₁ to S ₁ . Mapping processor 105 for converting to S _m and outputting as a parallel signal, and information modulators 107-1 to 107-107 for performing primary modulation with subcarriers obtained by orthogonalizing transmission secondary symbols S _{1 to} S _m , respectively. -M and an inverse Fourier transform unit (IFFT unit) 107-2 for performing inverse Fourier spread on the first-order modulated signal and transmitting the signal from the antenna 10.

  On the other hand, the receiver 2000 includes a Fourier transform unit (FFT unit) 200-1 for performing a Fourier transform on the signal received by the antenna 12, and an information demodulating unit 200-11 for primarily demodulating the Fourier transformed signal. 200-1m and maximum likelihood decoding is performed on the first demodulated signal, a secondary symbol is identified, and a maximum likelihood determiner 202 for calculating the primary symbol is transmitted from the primary symbol. And a decoding / bit conversion processing unit 204 for extracting a bit string.

  Here, the orthogonal transmission path corresponds to a transmission path by a plurality of subcarriers.

  FIG. 4 is a diagram for explaining a configuration of still another modification of the wireless communication system.

  In FIG. 4, a well-known RF front end is not shown.

  In FIG. 4, as an example of an orthogonal transmission path, a configuration in which information can be independently transmitted by, for example, m logical transmission paths by a code division multiplexing system.

That is, the transmitter 1000 encodes transmission bit strings D _{1 to} D _n to be transmitted and converts them into transmission primary symbols, converts the transmission primary symbols into m transmission secondary symbols S _{1 to} S _m, and performs parallel processing. An encoding / mapping processing unit 100 for outputting as a signal, information modulation units 107-11 to 107-1m for primary modulation of transmission secondary symbols S _{1 to} S _m , respectively, and primary modulation Spreading processing units 107-21 to 107-2 m for performing spreading processing on the signals with the corresponding spreading codes 1 to 2 and performing secondary modulation and transmitting from the antenna 10 are provided. Here, spreading code 1 to spreading code m are codes orthogonal to each other.

  On the other hand, the receiver 2000 includes despreading units 200-11 to 200-1m for despreading the signals received by the antenna 12 with the corresponding spreading codes 1 to m, and the despread signals. , Low-pass filters 200-21 to 200-2m for performing low-pass filtering processing, information demodulating units 200-31 to 200-3m for primarily demodulating the filtered signals, and primary Maximum likelihood decoding is performed on the demodulated signal, a secondary symbol is identified, a maximum likelihood determiner 202 for calculating the primary symbol, and a decoding / decoding for extracting a bit string transmitted from the primary symbol A bit conversion processing unit 204.

  Here, the orthogonal transmission path corresponds to a transmission path spread by a plurality of mutually orthogonal spreading codes.

  FIG. 5 is a diagram for explaining a configuration of still another modification of the wireless communication system.

  In FIG. 5, the well-known RF front end is not shown.

  In FIG. 5, as an example of the orthogonal transmission path, a configuration is shown in which information can be independently transmitted by, for example, three logical transmission paths by the frequency division multiplexing method.

In transmitter 1000, transmission bit strings D _{1 to} D ₄ to be transmitted are each converted into corresponding four systems of transmission primary symbols by QPSK modulator 102-1. The mapping converter 104 converts the data of the transmission primary symbol into the transmission secondary symbols S _{1 to} S ₃ corresponding to the three signal points on the constellation. The transmission secondary symbols S _{1 to} S ₃ are modulated into a signal of a plurality of carriers by the transmission modulation circuit 106-1, multiplexed by the frequency division multiplexing circuit 106-2 by the frequency division multiplexing method, and sent to the transmission path. The

In the receiver 2000, the signal from the transmission path is converted into three systems of secondary symbols by the frequency demultiplexing circuit 200-1 and the reception demodulation circuit 200-2. The maximum likelihood determiner 202 applies maximum likelihood decoding to the secondary received symbols S _{1 to} S ₃ , thereby converting it into a plurality of received bit strings D _{1 to} D _n by a procedure for performing mapping opposite to that on the transmission side. To do. Although not shown, the decoding / bit conversion processing unit 204 further performs decoding and bit conversion processing on the received bit strings D _{1 to} D _n and outputs received signal bits.

In the above, some examples of orthogonal transmission paths have been described. In the following, the frequency multiplexing division method will be mainly described as a method for realizing an orthogonal transmission path, but a combination with other methods will be referred to as appropriate. The following description is merely an example from among the methods for realizing the orthogonal transmission path as described above. In the wireless communication system according to the present embodiment, other orthogonal transmission paths and other orthogonal transmissions are used. It is also possible to use a combination of roads.
(Encoding and assignment process)
Hereinafter, the “encoding and assignment process” in the wireless communication system as described above will be described in more detail.

First, as a specific example, a procedure for converting _three transmission primary symbols M _{1 to} M ₃ into two transmission secondary symbols S _{1 to} S ₂ will be described. In addition, the orthogonal transmission path is not particularly limited, but a case will be described as an example in which signals are transmitted in synchronization with two transmission paths by frequency division multiplexing.

FIG. 6 is a diagram showing an arrangement on the constellation of signal points corresponding to three systems of transmission primary symbols M _{1 to} M ₃ .

As shown in FIGS. 6A, 6B, and 6C, when the three primary transmission symbols M _{1 to} M ₃ are QPSK modulated in gray (hereinafter simply referred to as QPSK), Transmission primary symbols are combined into _two transmission secondary symbols S _{1 to} S ₂ .

  In this case, the conversion to the transmission secondary symbol is expressed as follows.

FIG. 7 shows the signal point arrangement of the _two transmission secondary symbols S _{1 to} S ₂ , the signal point number of each signal point, and the data number corresponding to the signal point number (a number uniquely assigned to the transmission bit string) It is a figure which shows the value which shows the binary number expression of a transmission bit sequence as a table | surface.

In QPSK, the transmission primary symbols M _{1 to} M ₃ have 2 bits / signal point assignment, so the signal point set of the transmission secondary symbol S ₁ or the transmission secondary symbol S ₂ is 6 bits, and 64 kinds of mapping of signals. It has become. However, as shown in the respective tables of the S ₁ component and the S ₂ component, one signal point is an arrangement in which four data numbers (transmission bit strings) overlap each other, and there are 64/4 = 16 signal point positions. In the following, as described above, a plurality of data numbers (transmission bit strings) correspond to one signal point on the signal space diagram so as to overlap each other as described above. I will call it.

In this case, the receiving side which has received such a signal point, S ₁ component alone or, S ₂ component alone can not solve the degeneracy of the information indicated by the signal point, S ₁ component and S ₂ component signals By using the point information, the information can be obtained.

As described above, at this time, when the signal point positions are determined based on the S ₁ component and the S ₂ component received at the same time, the likelihood calculation is performed by the maximum likelihood determiner 202, and which signal point is received at each signal point. It is quantified whether it is the best match. Here, the likelihood calculation value is a dimensionless value.

FIG. 8 is a diagram showing the relationship between the S ₁ component signal point and the S ₂ component signal point in the example shown in FIG.

As shown in FIG. 8, data number 51 (transmission bit string 110011), data number 55 (transmission bit string: 110111), data number 59 (transmission bit string: 1111011), data number 63 (transmission) are transmitted to one signal point of the S ₁ component. Bit string: 111111) is degenerated.

In these S ₁ components, degenerate signal points correspond to different quadrants in the signal space diagram, respectively, in the S ₂ component. That is, the S ₂ component is arranged so as to have a margin in the mutual distance.

FIG. 9 is another diagram showing the relationship between the S ₁ component signal point and the S ₂ component signal point in the example shown in FIG.

As shown in FIG. 9, S _2-component one signal point data number 60 of (transmission bit sequence: 111100), the data number 61 (transmission bit sequence: 111101), the data number 62 (transmission bit sequence: 111110), the data number 63 ( Transmission bit string: 111111) is degenerated.

In these S ₂ components, degenerate signal points correspond to different quadrants in the signal space diagram, respectively, in the S ₁ component. That is, the S ₁ component is arranged so as to have a margin in the mutual distance.

  Of course, the arrangement of signal points as shown in FIGS. 7 to 9 is merely an example, and is not limited to such an arrangement. However, with the arrangement as shown in FIGS. 7 to 9, even if the reception status of one component deteriorates, the signal point is immediately lost in a situation where the other reception status does not deteriorate correspondingly. Can be accurately identified.

  The signal point arrangement procedure as shown in FIGS. 7 to 9 will be described as an example of a preferable procedure when the transmission primary symbol is expressed by QPSK modulation.

  FIG. 10 is a conceptual diagram showing a signal point arrangement procedure for multiplexed signals.

1) As shown in FIG. 10A, the m transmission primary symbols M _{1 to} M _m are directly mapped onto the constellation of the transmission secondary symbols S _{1 to} S _m .

In this sense, the components of the transmission secondary symbols corresponding to the _m transmission primary symbols M _{1 to} M _m are referred to as “principal components”. The main components are represented by symbols S ₁ ′ to S _m ′.

Here, for convenience of explanation, it is assumed that the first m transmission primary symbols M _{1 to} M _m of _n transmission primary symbols M _{1 to} M _n are converted as principal components. However, the transmission primary symbol selected for principal component conversion is not limited to such selection as long as it is m systems.

  2) (n−m) transmission primary symbols are as follows.

2-1) First, as shown in FIG. 10B, the amplitude of the (m + 1) th transmission primary symbol on the IQ plane is set to w ¹ times (w is a positive number smaller than 1), and the transmission secondary symbol Is superimposed on the principal component on the constellation. This is called “transmission signal point hierarchization (primary hierarchization)”. FIG. 11B shows the case where w = 0.5.

2-2) Subsequently, (m + i) th (2 ≦ i ≦ (n- m)) the amplitude of the IQ plane of the transmitted primary symbol as ^{w i} times, the on constellation transmit secondary symbol ( i-1) It repeats superimposing on the signal layer made into the next hierarchy from i = 2 to i = (nm). This is called “i-th layering of transmission signal points”.

Therefore, for example, when the main component is quadrature phase shift keying modulation (ie, QPSK), the arrangement of signal points after i-th layering is 4 ^{i + 1} quadrature amplitude modulation: QAM). For example, in FIG. 10B, since it is after the first layering, 4 ² quadrature amplitude modulation, that is, 16QAM is obtained.

Here, the fact that the transmission primary symbol M ₃ is superimposed on the principal component S ₁ ′ by the primary layering will be expressed as follows.

<1 | 3>
Similarly, for example, the transmission primary symbol M ₃ is superimposed on the principal component S ₁ ′ by the primary layering and the transmission primary symbol M ₄ is superimposed on the secondary layering as follows. I will express it in

<1 | 3,4>
Therefore, when the three primary transmission symbols M _{1 to} M ₃ are principal components S ₁ ′ to S ₂ ′ and the transmission primary symbol M ₃ is superimposed on each of them by primary hierarchization, respectively. It is expressed as follows.

Transmission secondary symbol S ₁ : <1 | 3>
Transmission secondary symbol S ₂ : <2 | 3>
Similarly, for the four transmission primary symbols M _{1 to} M ₄ , the principal components are S ₁ ′ to S ₃ ′, and the transmission primary symbol M ₄ is superimposed on each of these by primary layering. The case is expressed as follows.

Transmission secondary symbol S ₁ : <1 | 4>
Transmission secondary symbol S ₂ : <2 | 4>
Transmission secondary symbol S ₃ : <3 | 4>
3) Transmission secondary symbols S _{1 to} S _m are transmission primary symbols other than “(own principal component) and (transmission primary symbol used for layering)”, that is, principal components other than themselves. About degenerate.

  Therefore, as data number assignment, the degenerated data numbers are distinguished by the quadrants that belong on the IQ plane of the principal components of the transmission secondary symbols that are cyclically adjacent. This is because, when a plurality of partial bit sequences constituting a transmission bit sequence correspond to transmission primary symbols, the partial bit sequences of principal components other than the transmission primary symbol, which are their own principal components, are degenerated. Correspond. Then, this degeneration can be solved according to which quadrant the principal component exists in another constellation whose primary component is the transmission primary symbol corresponding to the respective partial bit sequence that is degenerate. This corresponds to the correspondence between the data number (transmission bit string) and the transmission secondary symbol.

  For example:

i) When the transmission primary symbols M _{1 to} M ₃ of the three systems are principal components S ₁ ′ to S ₂ ′, and the transmission primary symbol M ₃ is superimposed on each of them by primary hierarchization. For the secondary symbol S ₁ = <1 | 3>, the degenerated data number is distinguished by the quadrant to which the signal of the data number corresponding to the transmission secondary symbol S ₂ = <2 | 3> belongs.

In other words, for the transmission secondary symbol S ₁ = <1 | 3>, the transmission primary symbol M ₂ is converted into a bit string by one combination from the two transmission primary symbols M ₁ and M ₃ , respectively. A further combination of the bit strings (00, 01, 10, 00) corresponds to a degenerate one signal point.

On the other hand, for the transmission secondary symbol S ₂ = <2 | 3>, the bit string of the transmission primary symbol M ₁ is respectively added to the bit string of one combination from the two systems of transmission primary symbols M ₂ and M _3. 00, 01, 10, 00) corresponds to the fact that one signal point is degenerated.

ii) For the four transmission primary symbols M _{1 to} M ₄ , the principal components are S ₁ ′ to S ₃ ′, and the transmission primary symbol M ₄ is superimposed on each of these by primary hierarchization. For the secondary symbol S ₁ = <1 | 4>, the degenerated data number is distinguished from the corresponding data number of the transmission secondary symbol S ₂ = <2 | 4> and S ₃ = <3 | 4>. Differentiate by the quadrant to which the signal belongs.

For the transmission secondary symbol S ₂ = <2 | 4>, the degenerated data numbers are distinguished from the corresponding data numbers of the transmission secondary symbols S ₃ = <3 | 4> and S ₁ = <1 | 4>. It is distinguished by the quadrant to which the signal belongs.

For the transmission secondary symbol S ₃ = <3 | 4>, the degenerated data numbers are distinguished by the corresponding data numbers of the transmission secondary symbols S ₁ = <1 | 4> and S ₂ = <2 | 4>. It is distinguished by the quadrant to which the signal belongs.

  The same applies when the hierarchy is second or higher.

  In the above description, it has been described that all the principal components are hierarchized. However, for example, only one part of m principal components may be hierarchized. For the principal components that are not hierarchized, the transmission primary symbol corresponds to the transmission secondary symbol as it is.

Hereinafter, with respect to the four systems of transmission primary symbols M _{1 to} M ₄ , the principal components are S ₁ ′ to S ₃ ′, and the transmission primary symbol M ₄ is superimposed on each of these by primary hierarchization. explain.

  FIG. 11 is a diagram showing the signal point arrangement of the transmission primary symbol.

  FIG. 11 shows a signal arrangement of QPSK modulation in which the first quadrant is (00), the second quadrant is (10), the third quadrant is (11), and the fourth quadrant is (01).

With respect to such transmission primary symbols M _{1 to} M ₄ , transmission secondary symbols S _{1 to} S ₃ are generated by conversion represented by the following equation.

FIG. 12 is a diagram showing signal point numbers for each of the transmission secondary symbols S _{1 to} S ₃ .

FIG. 13 is a diagram for explaining combinations of transmission primary symbols M _{1 to} M ₄ corresponding to signal point numbers of transmission secondary symbols S _{1 to} S ₃ .

In FIG. 12, for example, signal point number 1 of the transmission secondary symbol S ₁ component corresponds to the transmission primary symbol M ₁ = (10) and the transmission primary symbol M ₄ = (10).

Signal point number 1 degenerates quadruplely for transmission primary symbol M ₂ and transmission primary symbol M ₂ , respectively.

Thus, for example, in FIG. 13, the transmission bit string (10000010) corresponding to signal point number 1 of the transmission secondary symbol S ₁ component is (10000010) of transmission secondary symbol S ₂ component signal point number 19 It corresponds to (10000010) symbol S ₃ component signal point number 35. The signal point number 19 corresponds to the first quadrant in the signal point arrangement of the transmission secondary symbol S ₂ component, and the signal point number 35 corresponds to the first quadrant in the signal point arrangement of the transmission secondary symbol S ₃ component. To do. For this reason, on the receiving side, likelihood determination is performed on the transmission secondary symbols transmitted simultaneously, and it is possible to determine which quadrant each of the transmission secondary symbol S ₂ component and the transmission secondary symbol S ₃ component belongs to. If it can be determined that the transmitted secondary symbol S ₁ component corresponds to the signal point number 1, it is possible to determine that the transmitted bit string is (10000010).

  The same applies to other signal points. Therefore, if the correspondence between the signal point number on the constellation for each transmission secondary symbol and the transmission bit string is shared between the transmitter and the receiver in advance, transmission on the receiver side Discriminated bit strings can be discriminated.

  Here, although not particularly limited, for example, as a likelihood calculation procedure, when the transmission primary symbol is QPSK, the following may be employed.

i) Likelihood calculation itself is also hierarchized to first determine which quadrant each transmitted secondary symbol belongs to, and then one of the transmitted secondary symbols S _{1 to} S ₃ is, for example, If the adaptive selection is made according to the quality of the reception state of the transmission path, and the likelihood calculation for discriminating the signal point for the next layer is performed, the number of orthogonal transmission paths is reduced and communication is performed. Even when the communication is performed, it is possible to maintain good communication quality.

ii) Likelihood calculation itself is also hierarchized. First, for one orthogonal transmission path adaptively selected according to the quality of the reception state of the transmission path, for example, for any transmission secondary symbol S ₁ , The maximum likelihood determination is made as to whether the signal corresponds to a signal point, and for the remaining two orthogonal transmission paths, for example, with respect to the transmission secondary symbols S _{2 to} S ₃ , it is determined to which quadrant each transmission secondary symbol belongs. Even when communication is performed by reducing the number of orthogonal transmission paths, it is possible to maintain good communication quality.

  The same applies when the number of orthogonal transmission paths increases.

  Next, a specific example of performing the secondary hierarchization will be described.

  FIG. 14 is a diagram for explaining a configuration of a wireless communication system for executing such a secondary hierarchization of transmission signal points.

  In the example of FIG. 14, it is assumed that a frequency division division type transmission line is used as the orthogonal transmission line. In FIG. 14, the RF front end is not shown.

  On the transmission side, the signal of the transmission primary symbol that has been primarily modulated by the four QPSK modulators 102-1 to 102-4 is converted into a transmission secondary symbol by the mapping converter 104, and then transmitted to the transmission modulation circuit 106-. 1 is modulated into a signal of a plurality of carriers, frequency division multiplexed by the frequency multiplexing circuit 106-2, and sent to the transmission line.

  On the receiving side, the signal from the transmission path is received, secondarily demodulated by the frequency demultiplexing circuit 200-1 and the reception demodulating circuit 200-2, converted into a secondary symbol, and then the maximum likelihood determiner 202. Thus, it is converted into a primary symbol and a corresponding bit string is output.

In addition, transmission secondary symbols S _{1 to} S ₂ are generated by conversion represented by the following formulas for transmission primary symbols M _{1 to} M ₄ .

  That is, when the above-described symbols are used, it is expressed as follows.

Transmission secondary symbol S ₁ = <1 | 4,3>
Transmission secondary symbol S ₂ = <2 | 3,4>
In this case, for the transmission secondary symbol S ₁ = <1 | 4, 3>, the degenerated data number is distinguished from the signal of the data number corresponding to the transmission secondary symbol S ₂ = <2 | 3, 4>. It is distinguished by the quadrant to which it belongs. For the transmission secondary symbol S ₂ = <2 | 3, 4>, the degenerated data number is distinguished from the signal of the data number corresponding to the transmission secondary symbol S ₁ = <1 | 4, 3>. Distinguish by the quadrant you belong to.

  FIG. 15 is a diagram showing the signal point arrangement of the multiplexed signal after the second layering in the configuration shown in FIG.

With the secondary hierarchy, the transmitted secondary symbols S ₁ and S ₂ are equivalent to 4 ³ quadrature amplitude modulation, that is, 64QAM signal arrangement, respectively.

  FIG. 16 is a diagram showing a relationship between signal point numbers and corresponding transmission primary symbols for the signal point arrangement shown in FIG.

In FIG. 16, the transmission secondary symbol S ₁ is degenerated for the transmission primary symbol M ₂ , and the transmission secondary symbol S ₂ is degenerated for the transmission primary symbol M ₁ .

  In FIG. 16, however, the degenerated symbols are not shown and are simply indicated by the symbol “XX”.

(Embodiment 2)
FIG. 17 is a diagram for explaining a configuration of a wireless communication system using a polarization multiplexing modulation system as an orthogonal transmission path.

  FIG. 17 shows a configuration in which the configuration of FIG. 5 is changed to correspond to the polarization multiplexing modulation system, and the RF front end is not shown.

  In the example of FIG. 17, a configuration is shown in which two of the orthogonal transmission paths are frequency multiplexing transmission lines and one is a polarization multiplexing transmission path.

That is, among the transmission secondary symbols S _{1 to} S ₃ , the transmission secondary symbols S _{1 to} S ₂ are transmitted through the vertical polarization transmission line, and the remaining transmission secondary symbols S ₃ are transmitted through the horizontal polarization transmission. Transmit on the road.

  FIG. 18 is a diagram for explaining the configuration of still another modification of the wireless communication system.

  In FIG. 18, as an example of an orthogonal transmission path, a configuration in which information can be independently transmitted by, for example, m systems of orthogonal transmission paths by a frequency division multiplexing system and a polarization multiplexing system.

  18, a transmitter 1000 includes an encoding / assignment processing unit 100, modulation circuits 102-1 to 102-n, a mapping converter 104, frequency multiplexing circuits 106-1a and 106-1b, a transmission unit 106-2a, 106-2b and transmission antennas 10a and 10b. The receiver 2000 includes receiving antennas 12a and 12b, receivers 201-1a and 201-1b, frequency demultiplexing circuits 200-2a and 200-2b, an interference compensation circuit 200-3, a propagation path matrix estimation circuit 200-4, It consists of a likelihood determiner 202 and a decoding / bit conversion processing unit 204.

Transmitter 1000 branches an information signal to be transmitted into n signals in encoding / assignment processing unit 100. Each system signal is individually modulated by the modulation circuits 102-1 to 102-n. The n modulation signals independently modulated by the modulation circuits 102-1 to 102-n are converted into m signals by the mapping converter 104, of which m ₁ and m ₂ systems (m ₁ + m ₂ = m, where m ₁ and m ₂ are natural numbers) signals are modulated into signals of a plurality of carriers by transmission modulation circuits 106-1a and 106-1b, respectively, and frequency multiplexed by frequency multiplexing circuits 106-2a and 106-2b. The frequency-multiplexed signals are frequency-converted and amplified independently by the transmitters 106-3a and 106-3b, respectively, and transmitted from the antennas 10a and 10b having two polarization planes.

In the receiver 2000, the receiving antennas 12a and 12b are two polarization receiving antennas. Signals received at the two polarization planes of the receiver 2000 are respectively input to subsequent receiving units 201-1a and 201-1b, where filtering, amplifier processing, frequency conversion, and the like are performed. Outputs from the receiving units 201-1a and 201-1b are input to frequency demultiplexing circuits 200-2a and 200-2b, respectively, and are demultiplexed into carrier unit signals of m ₁ and m ₂ systems. Each carrier signal demultiplexed by the frequency demultiplexing circuit estimates a propagation path matrix H for each carrier from a training signal included in each carrier by a propagation path matrix estimation circuit 200-4. If the two polarizations are vertical / horizontal polarization, a training signal is inserted into the transmission vertical / horizontal polarization signal, and a matched pulse is output when the reception side detects the training signal in the reception vertical / horizontal polarization signal. Apply a matched filter.

  The interference compensation circuit 200-3 performs interference compensation of the received signal using the propagation path matrix H detected in units of carriers. Interference compensation can be realized, for example, by applying a MMSE (Minimum Mean Square Error) method. The interference-compensated signal is primarily demodulated by the reception demodulation circuits 200-5a and 200-5b, and then input to the maximum likelihood determiner 202, where demodulation processing is performed on a carrier basis. Since the maximum likelihood determiner 202 outputs each information signal of the multicarrier signal independently, the decoding / bit conversion processing unit 204 converts the information signal into one signal and restores the transmitted information signal.

(Embodiment 3)
FIG. 19 is a block diagram for explaining a configuration of a wireless communication system according to the third embodiment.

  The configuration shown in FIG. 19 is a configuration obtained by modifying the radio communication system shown in FIG. 5 as described below.

  That is, in the configuration shown in FIG. 19, the mapping conversion function of the mapping converter is switched by the multiplicity controller.

  More specifically, in the configuration shown in FIG. 19, the multiplicity controller 110 on the transmission side uses the number of orthogonal transmission paths to be used in the frequency division division scheme according to the quality (S / N, etc.) of the transmission paths. Switch the hierarchy order and multiplicity (n / m). The variable map converter 104 ′ changes the number of transmission lines, the order of layering, and the multiplicity according to the control from the multiplicity controller 110. That is, under the control of the multiplicity controller 110, the mapping function used by the variable mapping converter 104 ′ and the multiplexing processing by the transmission modulation circuit 106-1 and the frequency multiplexing circuit 106-2 are changed.

  Such transmission path quality can be fed back from the receiver side to the transmitter side through a control channel. Then, the multiplicity controller 110 determines whether i) the number of usable orthogonal transmission lines, ii) information on switching of the order of layering and multiplicity (n / m), and iii) signal points depending on necessity. Information about which one to use as the correspondence relationship with the transmission bit string is similarly notified from the transmitter side to the multiplicity controller 210 on the receiver side using the control channel.

  The multiplicity controller 210 on the receiver side switches the paths of the frequency demultiplexing circuit 20-1 and the reception demodulation circuit 200-2 in accordance with the notification from the transmitter side, and determines the determination algorithm of the variable maximum likelihood determination unit 202 ′. Switch to execute the corresponding demodulation / decoding process.

  As an example of multiplicity control, for example, when there are a large number of orthogonal transmission lines that have an S / N better than a predetermined level and are determined to be usable, depending on the state of the transmission line at that time It is possible to adopt a configuration in which the multiplicity is small and the multiplicity is large when the number is small. As another example of multiplicity control, for example, it is possible to increase the multiplicity when the transmission path quality is good and to reduce the multiplicity when it is poor. Alternatively, as yet another example of multiplicity control, for example, it is possible to increase the layering order when the transmission path quality is good, and to reduce the layering order when the channel quality is poor. .

  In the above description, the frequency division multiplexing transmission path is described as the orthogonal transmission path. However, the orthogonal transmission path may be an orthogonal frequency division multiplexing transmission path. 20 is a configuration in which m is switched for controlling the multiplicity (n / m), but a configuration in which n is switched to change the multiplicity is also preferable.

(Embodiment 4)
FIG. 20 is a block diagram for illustrating a configuration of a wireless communication system according to the fourth embodiment.

  The configuration shown in FIG. 20 is a configuration obtained by modifying the radio communication system shown in FIG. 19 as described below.

  That is, in the configuration shown in FIG. 20, in addition to the configuration in which the mapping conversion function of the mapping converter is switched by the multiplicity controller, in addition to the frequency division multiplexing transmission path, a polarization multiplexing transmission path is also combined as an orthogonal transmission path. Use.

  More specifically, in the configuration shown in FIG. 20, the multiplicity controller 110 on the transmission side uses the frequency division division method and the polarization multiplexing method according to the quality of the transmission path (S / N, etc.). The number of orthogonal transmission lines, the order of layering, and the multiplicity (n / m) are switched. The variable map converter 104 ′ changes the number of transmission lines, the order of layering, and the multiplicity according to the control from the multiplicity controller 110. That is, under the control of the multiplicity controller 110, the mapping function used by the variable mapping converter 104 ′ and the multiplexing process by the frequency / polarization variable multiplexer 106 ′ are changed.

  The frequency / polarization variable multiplexer 106 ′ multiplexes the frequency division multiplexing transmission path used as the orthogonal transmission path and the combination of these and the polarization multiplexing. Here, although not particularly limited, for example, the number of frequency division multiplexing transmission paths to be changed in advance and the combination of polarization multiplexing are defined, and signal processing paths corresponding to these combinations are formed. A path can be switched by control from the severe controller 110.

  Such a transmission path quality can also be fed back from the receiver side to the transmitter side through a control channel. Then, the multiplicity controller 110 transmits i) the number of usable orthogonal transmission lines, ii) information on the order of layering and switching of the multiplicity (n / m), and iii) signal points and transmissions if necessary. Information about which one to use as the correspondence with the bit string is similarly notified from the transmitter side to the multiplicity controller 210 on the receiver side using the control channel.

  The multiplicity controller 210 on the receiver side switches the signal processing path of the frequency / polarization variable demultiplexer 200 ′ in accordance with the notification from the transmitter side, and switches the determination algorithm of the variable maximum likelihood determiner 202 ′. The corresponding demodulation / decoding process is executed.

  An example of multiplicity control is the same as in the third embodiment, and thus description thereof will not be repeated.

  According to the configuration of the wireless communication system of each embodiment described above, it is possible to maintain communication quality as a plurality of transmission paths, improve frequency utilization efficiency, and improve data transmission speed by multiplex communication. It is.

  In addition, according to the configuration of the wireless communication system of each embodiment, when data transmission is performed by multiplex communication, the multiplicity and the like are adaptively changed with respect to the change in communication quality of each of the plurality of transmission paths. Thus, communication can be performed while maintaining the communication quality as a whole.

  Embodiment disclosed this time is an illustration of the structure for implementing this invention concretely, Comprising: The technical scope of this invention is not restrict | limited. The technical scope of the present invention is shown not by the description of the embodiment but by the scope of the claims, and includes modifications within the wording and equivalent meanings of the scope of the claims. Is intended.

  100 encoding / assignment processing unit, 102-1 to 102-n modulator, 104 mapping conversion unit, 106, 107 transmission modulator, 200 reception demodulation unit, 202 maximum likelihood determination unit, 204 decoding / bit conversion processing unit, 103-1 to 103-n storage unit, 105 mapping processing unit, 1000, 1000 wireless transmitter, 2000 wireless receiver.

Claims (8)

A communication device for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other,
Encoding means for converting a partial bit string constituting a transmission bit string into n primary system (n: natural number) transmission primary symbols respectively corresponding to first signal points on a first constellation corresponding to a predetermined modulation method; ,
Conversion means for converting the n transmission primary symbols to m transmission (m: natural number) transmission secondary symbols, each corresponding to the second signal point on the second constellation, and fewer than n transmissions. With
Each of the second signal points in at least one of the transmission secondary symbols corresponds to a predetermined plurality of types of transmission bit strings that are degenerated.
A communication apparatus further comprising transmission modulation means for transmitting the m transmission secondary symbols for transmission through the plurality of orthogonal transmission paths. The converting means includes
Of the n transmission primary symbols, m transmission primary symbols are used as principal components, and the remaining (nm) transmission primary symbols are sequentially reduced in amplitude with respect to each principal component. The transmission primary symbols are arranged at the signal points of quadrature amplitude modulation on the second constellation by superimposing the transmission primary symbols on the m systems, respectively. The communication device according to claim 1, wherein the communication device converts the symbol. When the ratio of the n systems to the m systems is multiplicity,
The converting means changes the number of transmission primary symbols or the number of transmission secondary symbols by changing the multiplicity according to the quality of the transmission paths of the plurality of orthogonal transmission paths. The communication apparatus according to claim 1, further comprising a changing unit. A communication device for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other,
Receiving means for performing demodulation processing on the received signals from the plurality of orthogonal transmission paths and demodulating the received signals corresponding to the transmission secondary symbols, respectively;
In mapping of the signal space diagram, the likelihood is calculated for the signal point corresponding to the transmission secondary symbol for the received signal, the most likely symbol is identified as the received symbol, and the identified transmission secondary symbol is identified. Likelihood determining means for calculating a corresponding transmitted primary symbol,
The transmission primary symbol is converted on the transmission side so that the partial bit string constituting the transmission bit string corresponds to each of the n first signal points on the first constellation corresponding to the predetermined modulation scheme. The transmission secondary symbols are converted from the n transmission primary symbols to m transmission secondary symbols that are smaller than the n transmissions corresponding to the second signal points on the second constellation. Each of the second signal points in the transmission secondary symbol of at least one system is converted into a predetermined plurality of types of transmission bit strings and corresponds,
A communication apparatus further comprising decoding means for converting a transmission primary symbol calculated by the likelihood determining means into a corresponding bit string.   The mapping of the signal space diagram in the likelihood calculation of the likelihood determination means has m transmission primary symbols as principal components of the n transmission primary symbols, and the remaining (nm) systems. For the transmission primary symbols, the quadrature amplitude modulation on the second constellation is performed by superimposing the transmission primary symbols on the m systems of transmission primary symbols by hierarchization in which the amplitude is sequentially reduced for each principal component. The communication apparatus according to claim 4, wherein the communication apparatus corresponds to a signal obtained by converting the transmission primary symbol into the transmission secondary symbol. When the ratio of the n systems to the m systems is multiplicity,
In order to change the number of transmission primary symbols or the number of transmission secondary symbols by changing the multiplicity according to the quality of the transmission paths of the plurality of orthogonal transmission paths, The communication apparatus according to claim 4, further comprising means for transmitting information on the quality of the road to the transmission side. A communication system for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other,
A transmission device, wherein the transmission device comprises:
Encoding means for converting a partial bit string constituting a transmission bit string into n primary system (n: natural number) transmission primary symbols respectively corresponding to first signal points on a first constellation corresponding to a predetermined modulation method; ,
Conversion means for converting the n transmission primary symbols to m transmission (m: natural number) transmission secondary symbols, each corresponding to the second signal point on the second constellation, and fewer than n transmissions. Including
Each of the second signal points in at least one of the transmission secondary symbols corresponds to a predetermined plurality of types of transmission bit strings that are degenerated.
Transmission modulation means for transmitting the m transmission secondary symbols for transmission through the plurality of orthogonal transmission paths, respectively.
A receiving device, wherein the receiving device is
Receiving means for performing demodulation processing on the received signals from the plurality of orthogonal transmission paths and demodulating the received signals corresponding to the transmission secondary symbols, respectively;
In mapping of the signal space diagram, the likelihood is calculated for the signal point corresponding to the transmission secondary symbol for the received signal, the most likely symbol is identified as the received symbol, and the identified transmission secondary symbol is identified. Likelihood determining means for calculating a corresponding transmitted primary symbol;
And a decoding unit that converts the transmission primary symbol calculated by the likelihood determination unit into a corresponding bit string. A communication method for transmitting information using a plurality of orthogonal transmission paths orthogonal to each other,
On the transmission side, the partial bit string constituting the transmission bit string is converted into n-system (n: natural number) transmission primary symbols respectively corresponding to the first signal points on the first constellation corresponding to a predetermined modulation method. Steps,
On the transmission side, the n transmission primary symbols are converted into m transmission (m: natural number) transmission secondary symbols corresponding to the second signal points on the second constellation, which are smaller than n transmissions. And a step of
Each of the second signal points in at least one of the transmission secondary symbols corresponds to a predetermined plurality of types of transmission bit strings that are degenerated.
The transmitting side further comprises a step of transmitting the m transmission secondary symbols for transmission through the plurality of orthogonal transmission paths, respectively.
Performing a demodulation process on the received signals from the plurality of orthogonal transmission paths on the receiving side, and demodulating the received signals corresponding to the transmission secondary symbols respectively;
On the receiving side, in mapping of the signal space diagram, for the received signal, likelihood is calculated for the signal point corresponding to the transmitted secondary symbol, the most likely symbol is identified as the received symbol, and the identified transmission Calculating a transmitted primary symbol corresponding to the secondary symbol;
The communication method further comprising a step of converting the calculated transmission primary symbol into a corresponding bit string on the receiving side.