WO2007135964A1 - 無線通信装置及び無線通信方法 - Google Patents
無線通信装置及び無線通信方法 Download PDFInfo
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- WO2007135964A1 WO2007135964A1 PCT/JP2007/060166 JP2007060166W WO2007135964A1 WO 2007135964 A1 WO2007135964 A1 WO 2007135964A1 JP 2007060166 W JP2007060166 W JP 2007060166W WO 2007135964 A1 WO2007135964 A1 WO 2007135964A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03178—Arrangements involving sequence estimation techniques
- H04L25/03312—Arrangements specific to the provision of output signals
- H04L25/03324—Provision of tentative decisions
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/373—Predicting channel quality or other radio frequency [RF] parameters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0045—Arrangements at the receiver end
- H04L1/0047—Decoding adapted to other signal detection operation
- H04L1/005—Iterative decoding, including iteration between signal detection and decoding operation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03178—Arrangements involving sequence estimation techniques
- H04L25/03248—Arrangements for operating in conjunction with other apparatus
- H04L25/0328—Arrangements for operating in conjunction with other apparatus with interference cancellation circuitry
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03178—Arrangements involving sequence estimation techniques
- H04L25/03312—Arrangements specific to the provision of output signals
- H04L25/03318—Provision of soft decisions
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
Definitions
- the present invention relates to a wireless communication apparatus that performs iterative decoding reception of a signal.
- an adaptive array antenna (adaptive antenna).
- This adaptive array antenna can adjust the amplitude and phase by a weighting coefficient (hereinafter, this weighting coefficient is referred to as “weight”) multiplied by the received signal.
- weight a weighting coefficient multiplied by the received signal.
- SDMA space division multiple access
- Non-Patent Document 1 Information on SDMA technology is disclosed in Non-Patent Document 1 and the like, and SDMA is possible if the spatial correlation coefficient between terminal devices is lower than a predetermined value. The number can be improved.
- Non-Patent Document 2 information on spatial multiplexing technology is disclosed, for example, in Non-Patent Document 2, and both a transmitter and a receiver are provided with a plurality of antenna elements, and the correlation of received signals between antennas is low. Spatial multiplexing transmission can be realized in a propagation environment.
- the transmitter transmits different data sequences from different antennas using a physical channel having the same time, the same frequency, and the same code for each antenna element.
- the receiver is different from the received signals with multiple antennas provided Separate reception based on data series.
- the transmitter and receiver When performing SDM transmission, the transmitter and receiver have the same number of antennas in an environment where there are many scatterers between the transmitter and receiver under sufficient SZN (signal-to-noise ratio) conditions.
- the communication capacity can be expanded in proportion to the number of antennas.
- Non-Patent Document 3 Information on the SDM reception method is disclosed, for example, in Non-Patent Document 3, and transmission sequences from multiple wireless communication devices include MMSE (Minimum Mean squared error), ML (Maximum Likelihood), and iterative decoding. Separate reception is possible using a technique such as reception.
- MMSE Minimum Mean squared error
- ML Maximum Likelihood
- iterative decoding Separate reception is possible using a technique such as reception.
- the configuration of the iterative decoding reception includes a parallel interference cancellation PIC (parallel interference cancellation) PIC that performs decoding processing by removing interference signals in batch, and sequentially receives and receives spatially multiplexed signals from the received signals.
- a successive interference canceller SIC Successessive Interference Cancellation
- the hard canceller uses a hard decision value, so it is compared to the soft canceller.
- the circuit scale of the receiving apparatus can be reduced, which is advantageous in terms of power consumption and cost.
- Non-patent literature 1 T. Ohgane et al, ⁇ study on a channel allocation scneme with an adaptive array in SDMA, "IEEE 47th VTC, Page.725-729, vol.2 (1997)
- Non-Patent Document 2 G.J.Foschini, "Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas, Bell Labs Tech. J., pp.4 to 59, Autumn 1996
- Non-Patent Document 3 G.J.Foschini, Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas, Bell Labs Tech. J., pp.4 to 59, Autumn 1996
- the receiver when canceling the interference, determines the transmission signal replica that has been erroneously determined, the error in channel estimation or channel fluctuation, the hardware error (the frequency error of the local oscillator between transmission and reception, the DZA on the transmission side).
- Error factors such as phase error due to the sampling clock frequency error between the converter and the DZA converter on the receiving side (residual frequency error, which is extremely powerful with automatic frequency control (AFC))! / ) Includes a residual phase error that cannot be completely captured by phase tracking), the interference signal component cannot be removed and the reception characteristics are deteriorated.
- the larger the transmission packet size the greater the impact of deterioration due to error factors such as phase errors due to hardware errors.
- the receiver When a soft canceller is used, the receiver performs a cancel operation in a weighted form based on the reliability information of the reception replica for the transmission signal at the time of cancellation. Can be kept small. However, when propagation channel estimation or channel fluctuation errors and hard errors are included, reception characteristics are degraded in the same way as hard cancellers.
- the present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a radio communication device with good reception characteristics.
- the wireless communication device of the present invention uses a received signal to calculate likelihood information for a transmission signal, and outputs from the likelihood calculating unit.
- a temporary determination unit that outputs a temporary determination value of the transmission signal based on the error, and an error component estimation that estimates an error of the reception replica with respect to the transmission signal based on the output of the temporary determination unit, the estimation result of the transmission channel, and the reception signal
- a decoding processing unit that performs error correction decoding processing on the received signal using likelihood information weighted based on the output of the error component estimation unit.
- the radio communication apparatus of the present invention uses a received signal to calculate likelihood information for the transmission signal, and an error for the transmission signal based on the output of the likelihood calculation unit.
- a first decoding unit that performs correction decoding processing and outputs a provisional decision value; a reception level for the transmission signal based on the output of the first decoding unit, the estimation result of the propagation channel, and the reception signal;
- An error component estimator for estimating the error of the precursor, and a second decoder for performing error correction decoding processing on the received signal using likelihood information weighted based on the output of the error component estimator. It is characterized by.
- the wireless communication device of the present invention includes a first decoding processing unit that generates a transmission signal estimation result and a propagation channel estimation in a wireless communication device that receives a spatially multiplexed transmission signal.
- a channel estimation unit that generates a result
- a replica generation unit that generates a reception replica for the transmission signal based on the estimation result of the transmission signal and the estimation result of the propagation channel, and one or more spatially multiplexed signals from the reception signal
- An interference cancellation unit that subtracts components, an error component estimation unit that estimates an error of the received replica, a separation and synthesis unit that separates and combines one or more spatially multiplexed signals from the output of the interference cancellation unit, and the separation and combination
- a likelihood calculating unit for calculating likelihood information for the output of the generating unit, a weighting unit for weighting the output of the likelihood calculating unit based on the output of the error component estimating unit, and
- a second decoding processing unit that performs error correction decoding processing using the output.
- the radio communication apparatus of the present invention is characterized in that the replica generation unit includes a re-encoding modulation unit that generates a transmission signal replica based on an estimation result of transmission symbols or transmission bit data.
- the replica generation unit generates a transmission signal replica based on an estimation result of the transmission signal, multiplies the estimation result of the propagation channel, and generates a reception replica for the transmission signal. It is characterized by generating.
- the wireless communication device of the present invention includes one or more antennas that receive the one or more spatially multiplexed signals, and the interference cancellation unit includes the one or more spatially multiplexed signals.
- the interference cancel signal is output for the number of antennas.
- the error component estimation unit estimates an error component based on a signal component obtained by subtracting reception replicas for all transmission signals from the reception signal. It is characterized by that.
- the error component estimation unit includes a transmission signal replica that is an output of the re-encoding modulation unit and a channel that is an output of the channel estimation unit. It is characterized in that reception replicas for all transmission signals are generated using the estimated values.
- the demultiplexing / combining unit generates demultiplexing / combining weights for demultiplexing and combining one or more spatially multiplexed signals from the output of the interference canceling unit.
- the error component estimation unit estimates an error component based on a signal component obtained by subtracting a reception replica for a part of transmission signals included in the transmission signal from the reception signal and the separation / synthesis weight. It is characterized by doing.
- the replica generation unit generates a reception replica for a part of transmission signals included in the transmission signal.
- the demultiplexing / combining unit generates demultiplexing / combining weights for demultiplexing and combining one or more spatial multiplexing signals from the output of the interference canceling unit, and the error
- the component estimation unit is characterized in that an error component is estimated based on a signal component obtained by subtracting reception replicas for all transmission signals from the reception signal and the separation / synthesis weight.
- the error component estimation unit estimates an error component based on reliability information and reception power information of the transmission signal replica.
- the wireless communication apparatus of the present invention is characterized in that it includes a stream reception quality estimation unit that generates reliability information of the transmission signal replica.
- the error component estimation unit generates the reception power information using an output of the channel estimation unit.
- the error component estimation unit is configured to process all transmission signals from reliability information of the transmission signal replica, reception power information thereof, and the reception signal.
- the error component is estimated based on the signal component obtained by subtracting the received replica.
- the error component estimation unit subtracts reliability information of the transmission signal replica, reception power information thereof, and reception replicas for all transmission signals of the reception signal power. Signal components obtained by processing, and in the separation and synthesis unit An error component is estimated based on the separation / synthesis weight.
- the wireless communication device of the present invention includes a detection unit that determines a transmission symbol using the received signal and outputs likelihood information for the determination result
- the first decoding processing unit includes: An error correction decoding process is performed based on the output of the detection unit, and the re-encoding modulation unit performs error correction encoding and modulation processing again on the determination output of the first decoding processing unit, A replica for each symbol of a transmission signal is generated.
- the detector includes a signal separator that multiplies a received signal by a spatial multiplexing weight to separate a received symbol sequence, and the received symbol sequence is the likelihood information. And a demodulating unit for converting the data into a demodulator.
- the reliability information of the transmission signal replica is generated based on likelihood information obtained by the first decoding processing unit. .
- the demodulation unit includes a second likelihood calculation unit, and the reliability information of the transmission signal replica is a likelihood obtained by the second likelihood calculation unit. It is generated based on the degree information.
- the detector is characterized by separating and detecting a spatially multiplexed signal by multiplying the received signal by an MM SE weight.
- the detection unit multiplies the received signal by an MM SE weight to separate a plurality of spatial multiplexed streams and extract one spatial multiplexed stream, The transmission symbol is determined, and likelihood information for the determination result is output.
- the detector is characterized in that the received signal is multiplied by a ZF weight to separate and detect a spatially multiplexed signal.
- the reliability information of the transmission signal replica is generated based on reception weight information that separates a spatially multiplexed signal used in the detection unit, and the reception weight information is The MMSE weight or the ZF weight is included.
- the wireless communication apparatus of the present invention uses a received signal to calculate likelihood information for a transmission signal, and uses the received signal to calculate a hard decision result for the transmission signal. Weighted based on the output of the symbol hard decision unit, the output of the symbol hard decision unit, the estimation result of the propagation channel and the error estimation unit for estimating the error with respect to the transmission signal based on the received signal, and the output of the error estimation unit And a decoding processing unit that performs error correction code processing on the received signal using likelihood information.
- the wireless communication apparatus of the present invention includes a replica generation unit that generates a reception replica for a transmission signal based on an output of the symbol hard decision unit and a propagation channel estimation result, and an output of the replica generation unit. And an interference canceling unit that cancels an interference component using the received signal.
- the present invention provides a symbol hard decision unit that generates a hard decision result of a transmission signal and a channel estimation unit that generates a propagation channel estimation result in a wireless communication device that receives a transmission signal that has been subjected to spatial multiplexing transmission.
- a replica generation unit that generates a reception replica for the transmission signal based on the hard decision result of the transmission signal and the estimation result of the propagation channel, and subtracts one or more spatially multiplexed signal components from the reception signal
- An interference cancellation unit an error component estimation unit that estimates an error of the reception replica, a separation / combination unit that separates and combines one or more spatially multiplexed signals from the output of the interference cancellation unit, and an output of the separation / combination unit
- a likelihood calculating unit for calculating likelihood information a weighting unit for weighting the output of the likelihood calculating unit based on the output of the error component estimating unit, and the output of the weighting unit
- the wireless communication apparatus includes a decoding processing unit that performs error correction decoding processing.
- the present invention provides a radio communication device that receives a transmission signal that has been subjected to spatial multiplexing transmission, a demodulation unit that calculates likelihood information for the transmission signal using the reception signal, and a hard decision result of the transmission signal.
- a symbol hard decision unit to generate, a channel estimation unit to generate a propagation channel estimation result, and an error estimation unit to estimate an error with respect to a transmission signal based on the symbol hard decision result, the channel estimation result, and the received signal
- a first weighting unit that weights the output of the demodulation unit based on the output of the error estimation unit, and a decoding processing unit that performs error correction decoding based on the output of the first weighting unit It is characterized by that.
- the radio communication apparatus of the present invention includes a replica generation unit that generates a reception replica for a transmission signal based on the estimation result of the transmission signal and the estimation result of the propagation channel, and at least one of the reception signals
- An interference cancellation unit for subtracting the spatially multiplexed signal component of the
- the error component estimator for estimating the error of the received replica
- the demultiplexer / synthesizer for separating and synthesizing one or more spatial multiple signals from the output of the interference cancellation unit, and the likelihood correction for the output of the demultiplexer / synthesizer
- error correction decoding processing is performed.
- a decoding processing unit for performing the processing.
- the present invention provides a radio communication apparatus that receives a transmission signal that has been spatially multiplexed and transmitted, based on a signal separation unit that separates the spatially multiplexed signal from the received signal, and an output of the signal separation unit.
- a demodulator that calculates likelihood information for the transmission signal; a first decoding processor that performs error correction decoding based on an output of the demodulator; a channel estimator that generates a propagation channel estimation result; and the transmission Based on the signal estimation result and the propagation channel estimation result, a replica generation unit that generates a reception replica for the transmission signal, an interference cancellation unit that subtracts one or more spatially multiplexed signal components from the reception signal, An error component estimator for estimating the error of the reception brick, a demultiplexer / synthesizer for separating and synthesizing one or more spatial multiplexed signals from the output of the interference canceler, A likelihood calculation unit for calculating degree information, a weighting unit for weighting the output of the likelihood calculation unit based on the output of the error component estimation unit, and the weighting unit based on the output of the likelihood calculation unit And a second decoding processing unit that performs error correction decoding based on the output of the first likelihood correction unit. is there.
- the present invention provides a radio communication apparatus that receives a spatially multiplexed transmission signal, based on a signal separation unit that separates the spatially multiplexed signal from the received signal, and an output of the signal separation unit
- a demodulator that calculates likelihood information for the transmission signal, a symbol hard decision unit that calculates a hard decision result for the transmission signal based on the output of the signal separation unit, an output of the symbol hard decision unit, and the channel estimation unit
- An error estimation unit that estimates an error with respect to a transmission signal based on the output and the received signal, a first weighting unit that weights the output of the demodulation unit based on the output of the error estimation unit, and the first weighting unit
- a first decoding processing unit that performs error correction decoding based on the output of the channel, a channel estimation unit that generates a propagation channel estimation result, the transmission signal estimation result and the propagation channel estimation result Based on the results, a replica generation unit that generates a reception replica for the transmission signal, an interference cancellation unit that
- the present invention provides a radio communication apparatus that receives a transmission signal that has been subjected to spatial multiplexing transmission, using a modulation scheme identifying unit that identifies a modulation scheme of the received signal from the received signal, and the received signal to the transmission signal.
- a demodulation unit that calculates likelihood information, a symbol hard decision unit that generates a hard decision result of a transmission signal, a channel estimation unit that generates an estimation result of a propagation channel, the symbol hard decision result, the channel estimation result, and the An error estimation unit that estimates an error with respect to a transmission signal based on a received signal; a first bit selection unit that selects a bit extraction position of an error with respect to a transmission signal based on an output of the modulation scheme specifying unit; A first weighting unit that weights the output of the demodulation unit based on the output of the first bit selection unit, and a first decoding processing unit that performs error correction decoding based on the output of the first weighting unit It is characterized by having.
- the radio communication apparatus of the present invention includes a replica generation unit that generates a reception replica for a transmission signal based on the estimation result of the transmission signal and the estimation result of the propagation channel, and at least one of the reception signals
- An interference cancellation unit that subtracts the spatially multiplexed signal component of the signal, an error component estimation unit that estimates an error of the received replica, and a demultiplexing combination that separates and combines one or more spatial multiple reception signals from the output of the interference cancellation unit
- a likelihood calculating unit that calculates likelihood correction information with respect to the output of the separating and synthesizing unit, and a second bit for selecting a bit extraction position of an error with respect to the transmission signal based on the output of the modulation scheme specifying unit Based on the output of the bit selection unit, the second bit selection unit, the second weighting unit for weighting the output of the likelihood calculation unit, and the output of the second weighting unit, an error correction decoding process is performed.
- the replica generation unit generates a replica of a transmission signal based on an estimation result of a transmission signal, and multiplies the estimation result of the propagation channel to receive a replica of the transmission signal. Is generated.
- the wireless communication device of the present invention includes one or more antennas that receive the one or more spatially multiplexed signals, and the interference cancellation unit includes the one or more spatially multiplexed signals.
- the interference cancel signal is output for the number of antennas.
- the error component estimation unit estimates an error component based on a signal component obtained by subtracting a reception replica for all transmission signals from the reception signal. It is characterized by.
- the demultiplexing / combining unit generates demultiplexing / combining weights for demultiplexing and combining one or more spatial multiplexing signals from the output of the interference cancellation unit.
- the error component estimation unit estimates an error component based on a signal component obtained by subtracting a reception replica for a part of transmission signals included in the transmission signal from the reception signal and the separation / synthesis weight. It is characterized by doing.
- the replica generation unit generates a reception replica for a part of transmission signals included in the transmission signal.
- the demultiplexing / combining unit generates a demultiplexing / combining weight for demultiplexing and combining one or more spatial multiplexing signals from the output of the interference cancellation unit, and the error component estimating unit Is characterized in that an error component is estimated based on a signal component obtained by subtracting reception replicas for all transmission signals from the reception signal and the separation / synthesis weight.
- the error component estimation unit estimates an error component based on reliability information and reception power information of the transmission signal replica.
- the symbol hard decision unit selects a signal point closest to a transmission signal candidate point for each transmission symbol and outputs the signal point.
- the first likelihood correction unit includes an output of a demodulation unit. The force and the output of the weighting unit are added.
- the first likelihood correction unit selects a higher likelihood of the output of the demodulation unit and the output of the weighting unit, and outputs the selected likelihood It is characterized by this.
- the first likelihood correction unit is configured such that when the CRC included in the output of the demodulation unit is correct based on the CRC assigned to each transmission stream, the likelihood of the demodulation unit If the CRC is wrong, the likelihood output from the weighting unit is selected.
- the first likelihood correction unit adds the output of the first weighting unit and the output of the weighting unit.
- the first likelihood correction unit selects a higher likelihood of the output of the first weighting unit and the output of the weighting unit, and the selected likelihood Is output.
- the first likelihood correction unit is configured such that when the CRC included in the output of the demodulation unit is correct based on the CRC assigned to each transmission stream, the likelihood of the demodulation unit If the CRC is wrong, the likelihood output from the weighting unit is selected.
- the error estimation unit subtracts all reception replicas created based on the channel estimation signal and the symbol hard decision result from the reception signal. To do.
- the likelihood information for the spatially multiplexed signal is weighted based on the output of the error component estimator that estimates the error component when generating the received replica signal for the transmission signal. Even when the transmission signal replica includes an error, it is possible to suppress the deterioration of the reception characteristics.
- FIG. 1 is a configuration diagram of a radio communication apparatus according to Embodiment 1 of the present invention.
- FIG. 2 is a configuration diagram of the transmitting side of the wireless communication apparatus in the first embodiment of the present invention.
- FIG. 3 is a configuration diagram of a code modulation unit in Embodiment 1 of the present invention.
- FIG. 4 is a configuration diagram of a wireless communication apparatus according to Embodiment 3 of the present invention.
- FIG. 5 is another configuration diagram of the wireless communication apparatus according to the third embodiment of the present invention.
- FIG. 6 shows another configuration diagram of the wireless communication apparatus according to the third embodiment of the present invention.
- FIG. 7 is a configuration diagram of a wireless communication apparatus according to a fourth embodiment of the present invention.
- FIG. 8 is a configuration diagram of a transmitting side of a wireless communication device in a fourth embodiment of the present invention.
- FIG. 9 is a configuration diagram of a radio communication apparatus according to Embodiment 2 of the present invention.
- FIG. 10 is a configuration diagram of a transmitting side of a wireless communication device in a second embodiment of the present invention.
- FIG. 11 is another configuration diagram of the wireless communication apparatus according to the second embodiment of the present invention.
- FIG. 12 shows an example of a transmission frame configuration including a pilot subcarrier signal.
- FIG. 13 is a diagram showing a configuration of a wireless communication apparatus including a phase tracking circuit according to an embodiment of the present invention.
- FIG. 14 is a diagram showing another configuration of the wireless communication device including the phase tracking circuit according to the embodiment of the present invention.
- FIG. 15 is a configuration diagram of a wireless communication device lOOd according to the fifth embodiment of the present invention.
- FIG. 16 is a configuration diagram of radio communication apparatus 100e according to the fifth embodiment of the present invention.
- FIG. 17 is a configuration diagram of radio communication apparatus 100f according to the sixth embodiment of the present invention.
- FIG. 18 shows another configuration diagram of the wireless communication apparatus according to the sixth embodiment of the present invention.
- FIG. 19 is a configuration diagram of a wireless communication device 100g according to the seventh embodiment of the present invention.
- FIG. 20 is a configuration diagram of a wireless communication device 100h according to the eighth embodiment of the present invention.
- FIG. 21 is a diagram illustrating an example of an output value of c with respect to a control signal input.
- FIG. 23 is a diagram showing a table reference ROM used for calculating the correction value d (k).
- FIG. 1 is a diagram showing a configuration of radio communication apparatus 100 according to the first embodiment.
- the radio communication device 100 in FIG. 1 shows only the reception configuration, and the transmission configuration is shown in the radio communication device 100a in FIG.
- the reception configuration in this embodiment shows a configuration in which iterative decoding is performed using a parallel interference canceller (PIC).
- PIC parallel interference canceller
- the wireless communication device 100a spatially multiplex-transmits a plurality of M transmission sequences from a plurality (M, M> 1) of antennas 26-1 to M (hereinafter referred to as a spatial multiplex stream).
- M 2
- the configuration of the wireless communication device 100a in the case of the above is shown, it is not limited to this.
- transmission data generation unit 20 generates a bit data sequence z (k) to be transmitted to the wireless communication device.
- k represents a discrete time.
- the transmission path encoding unit 21 performs error correction encoding on the bit data sequence z (k) at a predetermined encoding rate.
- the serial-parallel conversion means (S ZP conversion means) 22 converts the data output of the transmission line code key unit 20 into a parallel data string corresponding to the number of antennas M, and outputs it as a transmission bit data sequence d (k).
- the interleaver 23-m performs an interleaving process on the transmission bit data sequence d (k).
- the modulation unit 24-m uses an I (In-Phase) signal and a modulation scheme of a predetermined multilevel level (a value indicating the amount of information transmitted in one symbol) for the output of the interleaver 23-m. Outputs a transmission symbol sequence X (k) mapped to a modulation symbol on the complex plane consisting of Q (Quadrature-Phase) signals.
- Transmitter 25-m frequency-converts transmission symbol sequence X (k), which is a baseband signal, and transmits antenna 26-m force as a high-frequency signal.
- X (k) which is a baseband signal
- antenna 26-m force as a high-frequency signal.
- m is a natural number less than or equal to M. Repeat the above operation for all m.
- a transmission symbol sequence at discrete time k transmitted from the m-th antenna cable is denoted as X (k).
- x (k) be a transmission symbol sequence at discrete time k at which a plurality of antenna (M> 1) forces are also transmitted.
- x (k) is an M-dimensional column vector
- the nth element is X (k) force.
- radio communication apparatus 100 The operation of radio communication apparatus 100 will be described using FIG. In the following, the operation after establishing frequency synchronization, phase synchronization, and symbol synchronization will be described.
- Nr multiple antennas 1 l to Nr receive the transmitted high-frequency signals.
- Nr is a natural number equal to or greater than the number M of spatial multiplexed streams to be transmitted.
- Receiving unit 2-n performs a quadrature detection process on the high-frequency signal received by antenna 1n, after amplification and frequency conversion processing (not shown), and a baseband signal consisting of an I signal and a Q signal Convert to In addition, the baseband signal is sampled as a discrete signal using AZD variations not shown.
- the received signal y (k) having the I signal and the Q signal sampled at the discrete time k as a real component and an imaginary component, respectively, is denoted.
- y (k) is denoted as the received signal at antennas l–l to Nr used for reception. This is a column vector whose nth element is y (k) force.
- received signal y (k) obtained by radio communication apparatus 100 is ( It can be expressed as in equation 1).
- H represents the propagation path change that the transmission symbol sequence X (k) from the radio communication apparatus 100a receives.
- the propagation path variation H is a matrix composed of (number of antennas Nr of the wireless communication device 100) rows X (number of transmission antennas M of the wireless communication device 100a) columns.
- the matrix element h in the i-th row and j-th column of the propagation path change H is a result of the high-frequency signal transmitted from the j-th transmission antenna in the wireless communication device 100a being received by the i-th antenna in the wireless communication device 100 This shows the fluctuation of the propagation path over time.
- n (k) represents a noise vector having Nr elements added at the time of reception by the Nr antennas of the wireless communication apparatus 100, and white noise with noise power ⁇ as shown in (Equation 2).
- I is the Nr-th order identity matrix.
- E [X] represents the expected value of X.
- Channel estimation unit 3 uses a known pilot signal or the like transmitted from radio communication apparatus 100 to calculate channel fluctuation estimated value B (hereinafter, channel estimated value) that is an estimated value for channel fluctuation H. Output.
- channel estimated value channel fluctuation estimated value
- signal demultiplexing section 4 uses channel estimation value B to generate a spatial demultiplexing weight for demultiplexing and receiving a transmission signal spatially multiplexed and transmitted from radio communication apparatus 100a. Perform multiplication on y (k). The output signal after the multiplication operation outputs a signal s (k) in which the amplitude and phase variations by the propagation path are equalized (hereinafter referred to as channel equalization).
- the signal separation unit 4 lacks information on the received signal quality only with the channel equalized signal, the received signal quality information q (
- the spatial multiplexing signal separation weight W for a desired transmission symbol sequence X (k) is defined as W.
- m m is calculated by applying methods such as ZF (Zero Forcing) and MMSE (Minimum Mean Square Error).
- the signal demultiplexing unit 4 multiplies the received signal y (k) by using the spatial demultiplexing weight W generated as described above and multiplies it as shown in (Equation 3), thereby obtaining another spatial demultiplexing stream.
- a signal s (k) is obtained by removing the interference signal component from.
- the output signal s (k) from the signal separation unit 4 is a symbol sequence (hereinafter referred to as a reception symbol) of a reception result for a transmission symbol sequence that is symbol-mapped by a modulation unit 24 on the transmission side using a modulation scheme of a predetermined multilevel modulation level. Series).
- Nr the pseudo-inverse matrix of propagation path fluctuation estimated value B is used.
- the reception quality information q (k) uses the reception SNR or the reception SINR of the reception symbol sequence s (k) obtained by signal separation.
- the received SNR or received SINR can be converted using the spatial demultiplexing weight W.
- the signal separation unit 4 can calculate a value based on the received SNR criterion as shown in (Equation 5) as the received quality information q (k).
- the demodulator 5-m performs a demapping process for converting the received symbol sequence s (k), which is the output of the signal separator 4, into a bit data string having a bit string power.
- the demodulator 5-m performs a demapping process for converting the received symbol sequence s (k), which is the output of the signal separator 4, into a bit data string having a bit string power.
- likelihood information for each bit is output.
- a log likelihood ratio is calculated as likelihood information for each bit.
- the method of calculating the log likelihood ratio is described in, for example, Non-Patent Document: Sanbo, “Digital Radio Transmission Technology”, pp. 275-279, Pearson Education Publication.
- demodulating section 5-m calculates (equation 6) as log likelihood ratio LLR (k) of the i-th bit in received symbol sequence s (k). Where L is used during transmission
- A is 0 or 1
- i is a natural number less than or equal to log (L).
- M is a natural number less than or equal to M.
- First decryption processor 6 includes a Dintarino 60-1 to M, a PZS converter 61, and a decoder 62. The operation is described below.
- the Dinterleaver 60-m is the reverse of the interleaving performed on the transmission side to the output of the likelihood information for each bit output from the demodulator 5-m (hereinafter referred to as the bit likelihood sequence). Bit data order is converted by operation.
- the parallel-serial conversion unit (PZS conversion unit) 61 converts the bit likelihood sequences output from the plurality of Dinter Renos 60-1 to M into serial bit likelihood sequences by a predetermined procedure.
- the decoding unit 62 performs error correction decoding processing on the bit likelihood sequence that is the soft decision value output from the PZS conversion unit 61. After the error correction decoding process, the decoding unit 62 outputs the bit data provisionally determined with the binary hard decision value as a provisional determination bit string b (k) for the transmission bit data sequence.
- Re-encoding modulation section 8 regenerates transmission symbol data based on provisional decision bit string b (k).
- FIG. 3 shows a detailed configuration of the re-encoding modulation unit 8.
- the transmission path encoding unit 31 performs error correction encoding on the provisional decision bit string b (k) according to a predetermined encoding rate and error correction method used at the time of transmission.
- serial / parallel conversion means (SZP conversion means) 32 converts the data output of the transmission path encoding unit 31 into a parallel data string corresponding to the number of antennas M in the same way as the transmission, and provisionally determined transmission bit data. Output as sequence d [1] (k).
- interleaver 33-m having the same interleaving pattern used at the time of transmission performs interleaving processing on temporary determination transmission bit data sequence d [1] (k).
- the modulator 34 modulates the output of the interleaver 33-m on the complex plane consisting of I (In-Phase) signal and Q (Quadrature Phase) signal using the predetermined multi-level modulation used at the time of transmission.
- the temporary decision transmission symbol sequence x [1] (k) mapped to the symbol is output.
- m is a natural number less than or equal to M.
- x [1] (k) is a provisionally determined transmission symbol sequence at discrete time k transmitted from a plurality of antennas (M> 1).
- x [1] (k) is an M-dimensional column vector
- the mth element consists of x [1] (k).
- the replica generation unit 9 is a provisional decision transmission symbol sequence x [1] that is an output of the re-code modulation unit 8 Using (k) and the channel estimation value B output from the channel estimation unit 3, a replica signal y [1] (k) of the received signal y (k) is generated as shown in (Equation 7).
- Gr is a matrix in which the diagonal component of r rows and r columns is set to 0 from the M-th unit matrix.
- Interference canceling section 10 considers the spatial multiplexed stream from the received signal y (k) output from receiving section 2 to remove the desired r-th spatial multiplexed stream as an interference signal, and removes the interference.
- the removed r-th spatial multiplexing stream is output. That is, as shown in (Equation 8), the interference cancellation output V (k) is calculated.
- r is a natural number from 1 to M
- y Cl] (k) is a replica signal.
- the interference cancel output V (k) is a column vector with Nr elements.
- Separation and Synthesizer 11 1 r synthesizes an interference cancellation output V (k) having Nr elements.
- Interference cancellation output synthesis methods such as maximum ratio synthesis (MRC synthesis) and MMSE synthesis (least square error synthesis) can be applied.
- the demultiplexing / combining unit 11-1r calculates the combined output u (k) for the desired r-th spatial multiplexing stream as shown in (Equation 9).
- b is the r-th column beta in channel estimate B
- the superscript H is the vector conjugate transpose.
- r is a natural number less than or equal to M.
- the error component estimation unit 13 estimates the error component E (k) of the replica signal in the interference cancellation unit 10. That is, as shown in (Equation 10), the error component estimation unit 13 uses the output B of the channel estimation unit 3 and the output of the re-encoding modulation unit 8 to generate replica signals y [ 1] (k) is generated and subtracted from the received signal y (k).
- error component estimation unit 13 As another operation of error component estimation unit 13, a replica signal obtained by using error component E (k) of the replica force signal in interference cancellation unit 10 and further weighting using synthesized weight Gr is used.
- the error component Er (k) may be estimated.
- the synthesized weight Gr is used to synthesize the interference cancellation output V (k) in the separation / synthesis unit 11r.
- the replica signal y [1] (k) for all spatially multiplexed streams is used. Is generated by subtracting and removing the received signal y (k) force, and further synthesized by the synthesis weight Gr for the interference cancel output V (k) in the separation / combination unit 11r.
- the weighted synthesized weight G is used for each spatially multiplexed stream so that the colored interference noise components are appropriately removed.
- the error component Er (k) of the replica signal is obtained. For this reason, optimal likelihood information can be obtained for each stream, and the accuracy of weighting of the likelihood information can be improved. As a result, the reception quality can be improved.
- the error component E (k) of the calculated replica signal can detect the interference noise power component for the symbol data series at each discrete time k as follows in addition to the noise power ⁇ component.
- the interference signal component may be reduced.
- An interference noise power component that remains as an interference signal residual component without being removed.
- the interference signal component may be reduced.
- An interference noise power component that remains as an interference signal residual component without being removed.
- the likelihood calculating unit 12— ! performs a demapping process for converting the combined output symbol data sequence u (k), which is the output of the separating and combining unit 11 1!:, Into a bit data sequence composed of bit sequences. .
- the log likelihood ratio LLR for each bit is calculated in the same manner as the demodulator 5.
- the log likelihood ratio LLRr, j (k) as shown in (Equation 12) is calculated as the reliability information at the i-th bit for the combined output symbol sequence u (k).
- L is the number of modulation multi-values used at the time of transmission
- A is 0 or 1
- i is a natural number of log (L) or less.
- M is M or less
- the lower natural number, br is the r-th column vector in channel estimate B, and r is a natural number less than or equal to M.
- Equation 12 is based on the assumption that the maximum ratio combining method is applied in the separation / synthesis unit 11. It is written in. That is, the reception quality information q (k) uses the SNR standard. The noise power in each antenna is omitted as common. Received power II br II 2 by MRC combining is applied to the rth spatially multiplexed stream. Where llxll 2 represents the norm for the vector X.
- the weighting unit 14 1 ! is a bit likelihood sequence for the r-th spatially multiplexed symbol that is the output of the likelihood calculation unit 12-r.
- correction according to the error component is performed. That is, the corrected bit likelihood sequence LLR [1] (k) as shown in (Equation 13) is calculated.
- d (k) is a function using the noise power ⁇ added at the time of reception by radio communication apparatus 100 and the output of error component estimation section 13 as parameters, as shown in (Equation 14). It can be expressed as a value.
- the function shown in (Equation 15) is used.
- d (k) tanh X ⁇ / ⁇ (k)) may be used instead of (Equation 15)!
- a is a constant value.
- the output of the weighting unit 14 1 r is input to the second decoding processing unit 6 (.
- the second decoding processing unit 6 ( 2 ) receives the Dinterleaver 60 ( 2 ) —1 to M,? / 3 converter 61 ( 2 ) and decoding unit 62 ( 2 ), and the configuration is the same as that of the first decoding processing unit 6. Therefore, detailed description thereof is omitted.
- the PZS conversion unit 61 (performs error correction decoding processing on the bit likelihood sequence output from, and outputs a binary hard decision value as a decoding result of the transmission bit data sequence.
- the interference component is interfered based on the output of the error component estimation unit 13 that performs the operation of detecting the error component of the replica signal using the received signal and the replica signal.
- the weighting unit 14 corrects the likelihood information for the spatially multiplexed signal that is separated and combined after cancellation.
- the radio communication apparatus of the present embodiment has significant interference noise power due to error factors such as channel estimation error and channel fluctuation error when interference determination includes a provisional determination output with a determination error. If included, the bit likelihood for the received symbol can be reduced. As a result, the radio communication apparatus according to the present embodiment performs error correction decoding processing using the bit likelihood described above to include a provisional decision output in which a decision error has occurred, a channel estimation error, and a channel variation error. Even when error factors due to such factors are included, degradation of reception characteristics can be suppressed.
- the node canceller having the temporary decision value as the binary hard decision value can have a simpler configuration than the soft canceller using the soft decision value, Furthermore, it is possible to obtain a radio communication device with good reception characteristics.
- the radio communication apparatus may be used in a configuration in which a soft canceller using a soft decision value is used instead of a temporary decision value. That is, the wireless communication device uses a soft interference canceling unit that performs soft canceling instead of the interference canceling unit 10.
- the wireless communication device uses a soft interference canceling unit that performs soft canceling instead of the interference canceling unit 10.
- the soft canceller in addition to the gain improvement effect by the soft canceller, it is possible to obtain the reception characteristic improvement effect by the weighting effect of the likelihood information by the error component estimation unit 13 that detects the error component of the reception replica, which is the configuration of the present invention. .
- the output of the second decoding processing unit is output as the decoding result for the final transmission bit data sequence.
- This output is again sent to the remodulation coding modulation unit 8.
- the re-encoding modulation unit 8, the replica generation unit 9, the interference cancellation unit 10, the error component estimation unit 13, the separation / synthesis unit 11, the likelihood calculation unit 12, the weighting unit 13, and the second decoding process In the section, the same processing as described above may be repeated. By such repeated processing, the effect of error correction in the force decoding unit that increases the processing delay is increased, and the reception characteristics are improved.
- FIG. 9 is a diagram showing a configuration of radio communication apparatus 200 according to the second embodiment.
- radio communication apparatus 200 in FIG. 9 shows only the reception configuration, and the transmission configuration is shown in radio communication apparatus 201 in FIG.
- the transmission and reception configuration when performing spatial multiplexing transmission is shown.
- the operation will be described in order with reference to FIG. 9 and FIG.
- the radio communication apparatus 201 transmits one transmission sequence from one antenna 26 (hereinafter referred to as a transmission stream).
- a transmission data generation unit 20 generates a bit data sequence z (k) to be transmitted to the wireless communication device.
- k represents a discrete time.
- Transmission path code key unit 21 performs error correction coding on the bit data sequence z (k) at a predetermined coding rate, and outputs it as a transmission bit data sequence d (k).
- the interleaver 23 performs an interleaving process on the transmission bit data sequence d (k).
- the modulation unit 24 uses a predetermined multi-level modulation method for the output of the interleaver 23, and uses V and the transmission symbol sequence mapped to the modulation symbols on the complex plane having the I signal and Q signal powers.
- Output X (k) The transmission unit 25 converts the frequency of the transmission symbol sequence X (k), which is a baseband signal, and transmits it from the antenna 26 as a high frequency signal.
- Nr antennas 1 l to Nr receive the transmitted high-frequency signals.
- Nr is a natural number of 1 or more.
- the receiving unit 2-n performs a quadrature detection process on the high-frequency signal received by the antenna 1n, after amplification and frequency conversion processing (not shown), and a baseband signal composed of an I signal and a Q signal. Convert to
- the baseband signal is sampled as a discrete signal using an AZD variation not shown.
- the received signal y (k) having the I signal and the Q signal sampled at the discrete time k as a real component and an imaginary component, respectively, is denoted.
- y (k) is denoted as a received signal at antennas 1-1 to Nr used for reception. This is a column vector whose nth element is V (k) force.
- h represents a propagation path change received by transmission symbol sequence X (k) from radio communication apparatus 2001, and is a column vector that also has a power (number of antennas Nr of radio communication apparatus 200).
- the i-th element h of the propagation path fluctuation h indicates the propagation path fluctuation when the high-frequency signal transmitted from the transmission antenna in the wireless communication apparatus 201 is received by the i-th antenna in the wireless communication apparatus 200.
- n (k) represents a noise vector having Nr elements added at the time of reception by the Nr antennas of radio communication apparatus 200, and white of noise power ⁇ as shown in (Expression 2) Let it be noise.
- I is the Nr-th order identity matrix.
- E [X] represents the expected value of X.
- Channel estimation section 3 uses a known pilot signal or the like transmitted from radio communication apparatus 100 to calculate channel fluctuation estimation value b (hereinafter, channel estimation value) that is an estimation value for channel fluctuation h. Output.
- equalization combining section 80 uses channel estimation value B to generate a weight for equalizing and combining the transmission signal transmitted from radio communication apparatus 201, and multiplies received signal y (k). Perform the calculation.
- the output signal after the multiplication operation outputs a signal s (k) in which the amplitude and phase fluctuations due to the propagation path are equalized (hereinafter referred to as channel equalization).
- the equalization / synthesis unit 80 lacks information on the received signal quality only with the channel equalized signal, so that the received quality of the separated signal s (k) is compensated for this.
- Information q (k) is also output.
- equalization combining section 80 calculates the equalization combining weight W for a desired transmission symbol sequence X (k) by applying a technique such as ZF or MMSE.
- the equalization combining unit 80 multiplies the received signal y (k) using the generated equalization combined weight W as shown in (Equation 17), thereby equalizing and combining the signal s ( k)
- the output signal s (k) of the equalization / combining unit 80 is a symbol sequence of a reception result for a transmission symbol sequence that is symbol-mapped by a modulation unit 24 of a predetermined multilevel modulation level in a modulation unit 24 on the transmission side.
- the received symbol sequence the received symbol sequence
- the reception quality information q (k) is the reception SN of the reception symbol sequence s (k) to be equalized and combined.
- the received SNR or received SINR can be converted using the equalization combined weight W.
- the received quality information q (k) is
- the likelihood calculating unit 12 performs demapping processing for converting the received symbol sequence s (k), which is the output of the equalizing and synthesizing unit 80, into a bit data string having a bit string power. Convert to bit string. In some cases, there is a method of outputting the hard decision value of the closest symbol candidate point to the received symbol point, but in the present invention, likelihood information for each bit is output.
- LLR logarithmic likelihood ratio
- L indicates the number of modulation multi-values used at the time of transmission
- A is 0 or 1
- i is a natural number of log 2 (L) or less.
- the Dinterleaver 60-1 is opposite to the interleaving performed on the transmission side for the output of the likelihood information for each bit output from the likelihood calculation unit 12 (hereinafter referred to as the bit likelihood sequence).
- the bit data order is converted by the operation of.
- the first decoding unit 62-1 performs error correction decoding processing on the bit likelihood sequence, which is the soft decision value output from the Dinterleaver 60-1, and outputs a binary value as its output. Bit data tentatively determined with the hard decision value is output as a tentative decision bit string b (k) for the transmission bit data series.
- the re-encoding modulation unit 8 uses the provisional decision bit sequence b (k) based on the provisional decision transmission symbol sequence x [1].
- (k) is output and the transmission symbol data is regenerated.
- the operation of the re-encoding modulation unit 8 is the same as that of the transmission data generation unit 20, the transmission path encoding unit 21, the interleaver 23, and the modulation unit 24 in the radio communication apparatus 201, and thus the description thereof is omitted. .
- the replica generation unit 9 outputs the provisional decision transmission symbol sequence x [1] that is the output of the re-code modulation unit 8
- the error component estimation unit 13 estimates the error component E (k) of the replica signal. That is, as shown in (Equation 10), the error component estimation unit 13 uses the output B of the channel estimation unit 3 and the output of the recode modulation unit 8 to generate replica signals By [1] for all transmission streams . (k) is generated, and the replica signal By [1] (k) is subtracted from the received signal y (k).
- the calculated error component E (k) of the replica signal can detect the interference noise power component for the symbol data series at each discrete time k as follows in addition to the noise power ⁇ component.
- phase variation error caused by hard error carrier frequency error, sampling frequency error
- the error power components 1) to 3) are generated independently.
- the weighting unit 14 Based on the output of the error component estimation unit 13, the weighting unit 14 corrects the bit likelihood series that is the output of the likelihood calculation unit 12 according to the error component. That is, the weighting unit 14 (the number 2
- the corrected bit likelihood sequence LLR [1] (k) as shown in 0) is calculated.
- d (k) is a function using the noise power ⁇ added at the time of reception of radio communication apparatus 200 and the output of error component estimation unit 13 as parameters, as shown in (Equation 14). It can be expressed as a value.
- the second Dinterleaver 60-2 performs a Dinterleaving process on the output of the weighting unit 14.
- the second decoding unit 62-2 performs error correction decoding processing on the bit likelihood sequence subjected to the deinterleaving processing, and outputs a binary hard decision value as a decoding result of the transmission bit data sequence.
- transmission is performed based on the output of the error component estimation unit 13 that performs the operation of detecting the error component of the replica signal using the received signal and the replica signal.
- the weighting unit 14 corrects the likelihood information for the stream.
- the radio communication apparatus includes a case where a provisional determination output with a determination error is included, or a case where error sound power is significantly included due to an error factor such as a channel estimation error and a channel fluctuation error.
- an error factor such as a channel estimation error and a channel fluctuation error.
- the wireless communication apparatus performs error correction decoding processing using the bit likelihood, so that a case in which a temporary determination output in which a determination error has occurred is included, a channel estimation error, a channel fluctuation error, etc. Even when error factors are included, it is possible to suppress the deterioration of reception characteristics.
- the node canceller with the temporary decision value as the binary hard decision value can have a simpler configuration than the soft canceller using the soft decision value, Furthermore, it is possible to obtain a radio communication device with good reception characteristics.
- the radio communication apparatus outputs the output of second decoding section 62-2 as the decoding result for the final transmission bit data sequence.
- the modulation code is input to the modulation unit 8 and described above. The process may be repeated.
- the processing delay increases due to the iterative processing, the effect of error correction in the decoding unit is enhanced, and reception characteristics are improved. It has an effect.
- FIG. 11 shows another configuration in the present embodiment.
- a temporary symbol determination unit 81 is used instead of the Dinter River 60-1, the first decoding unit 62-1, and the re-encoding modulation unit 8.
- symbol tentative determination section 81 uses symbol i-th log likelihood ratio LLR (k) in received symbol sequence s (k), which is the output of likelihood calculation section 12, to generate a symbol. Performs symbol hard decision for data series. Symbol temporary determination section 81 performs modulation again using the symbol hard decision result, and outputs provisionally determined transmission symbol sequence x [1] (k).
- the provisional determination output is obtained without performing the error correction decoding process. Therefore, the effect of the error correction decoding is not included when the replica is generated, and the characteristic is deteriorated. Compared to, it can be realized more easily and processing delay can be reduced.
- FIG. 4 is a diagram showing a configuration of radio communication apparatus 100b according to the third embodiment. Note that the radio communication device 100b in FIG. 4 shows only the reception configuration, and the transmission configuration is the same as the configuration shown in the radio communication device 100a in FIG.
- the reception configuration in the present embodiment shows a configuration in which decoding is performed using a normal interference interference canceller (PIC).
- PIC normal interference interference canceller
- demodulator 5 calculates bit likelihood sequence LLR (k) for the spatially multiplexed stream via receiver 2, channel estimator 3, and signal separator 4
- the stream reception quality estimator 7 uses the bit likelihood sequence LLR (k) for the spatially multiplexed stream obtained by the demodulator 5 to determine the received symbol sequence s (k) for the spatially multiplexed stream.
- the reception quality for each symbol is estimated. Where m is a natural number less than or equal to M. As shown in (Expression 21), the reception quality estimation for each symbol is the absolute value of log (L) bit likelihood LLR (k) for the kth received symbol in the mth spatial multiplexing symbol. From the one with the value to the one with the minimum value
- the stream reception quality estimation unit 7 regards the bit likelihood with the lowest reliability as the representative value of the symbol, and calculates the output value by the function g using it as an argument.
- the function g (x) applies a function shape whose output value increases as the input argument X increases.
- g (x) x 1/2 is used.
- As an output value 0 ⁇ Q (k) ⁇
- the error component estimation unit 15 estimates an error component E (k) for the r-th spatial multiplexed stream during the interference cancellation operation in the interference cancellation unit 10.
- the stream reception quality Q (k) of the m-th spatial multiplexing stream that is to be removed as interference removing the r-th spatial multiplexing stream. If the stream reception quality Q (k) is low mm, the error component approaches 0, and if the stream reception quality Q (k) is low, the mth spatial multiplexing stream depends on the reliability of the stream reception quality. Interference noise power is estimated on the assumption that interference power proportional to the received power of the system is generated as an error component.
- b is the m-th column vector in channel estimate B
- r is a natural number less than or equal to M. Also, if there are multiple spatial multiplex streams that are to be removed as interference to remove the r-th spatial multiplex stream, all of the space to be removed The above calculation is performed on the heavy stream, and the calculated sum of the interference noise power is used as the output value.
- the outputs of the demodulation units 5-1 to M are input to the first decoding processing unit 6.
- the first decoding processing unit 6 outputs the bit data provisionally determined with the binary hard decision value as a provisional determination bit string b (k) for the transmission bit data series.
- the operations of the demodulating sections 5-1 to M are the same as those in the first embodiment, and a description thereof will be omitted.
- the re-encoding modulation unit 8 performs the same operations as in the first embodiment. That is, the re-encoding modulation unit 8 regenerates transmission symbol data based on the temporary determination bit string b (k).
- the replica generation unit 9 outputs the provisional decision transmission symbol sequence x [1] that is the output of the re-code modulation unit 8
- Interference cancellation section 10 regards the spatial multiplexed stream excluding the desired r-th spatial multiplexed stream as an interference signal from received signal y (k), which is the output of receiver 2, and removes the interference.
- the removed r-th spatial multiplexing stream is output.
- Separation / synthesizing unit 11 1 r calculates a combined output u (k) by combining interference cancellation outputs V (k) having Nr elements.
- the separation / synthesizing unit 11 1 r uses the log-likelihood ratio LLRr, j (k) as shown in (Equation 12) as reliability information for the i-th bit for the combined output symbol sequence u (k). Is calculated.
- r is a natural number less than or equal to M, and for all r, the same operation as in the first embodiment I do. The description of the operation of the separation / synthesis unit 11r is omitted.
- the weighting unit 14-1 r is a bit likelihood for the r-th spatially multiplexed symbol that is the output of the likelihood calculation unit 12-r.
- the degree series is corrected according to the error component.
- D (k) can be expressed as a function value using as parameters the noise power ⁇ added at the time of reception of the wireless communication device 100 and the output of the error component estimation unit 15 as shown in (Equation 24).
- the function shape reduces d (k) as the error component E (k) of the reblka signal increases.
- the function shown in (Equation 25) is used.
- the output of the weighting unit 14 1 r is input to the second decoding processing unit 6 (2) .
- the second decryption processing unit 6 ( 2 ) has a Dinterleaver 60 ( 2 ) —1 to M,?
- the configuration is composed of a / 3 converter 61 ( 2 ) and a decoding unit 62 ( 2 ), and has the same configuration as the first decoding processing unit 6, and thus detailed description thereof is omitted.
- the decoding unit 62 ( 2) performs error correction decoding processing on the bit likelihood sequence output from the PZS conversion unit 61 ( 2), and converts the binary hard decision value to the decoding result of the transmission bit data sequence.
- the stream reception quality estimation unit 7 receives each estimated symbol of a replica signal to be removed as an interference signal.
- the bit likelihood for the received symbol is corrected to be small, assuming that the probability that the provisional decision output includes an error is high.
- the hard canceller that uses the temporary decision value as the binary hard decision value can be configured more simply than the soft canceller that uses the soft decision value.
- the output of second decoding processing unit 6 is output as a decoding result for the final transmission bit data sequence.
- This output is again sent to re-encoding modulation unit 8.
- re-encoding modulation unit 8 replica generation unit 9, interference cancellation unit 10, error component estimation unit 15, separation / synthesis unit 11, likelihood calculation unit 12, weighting unit 14, and second decoding processing In part 6 (the same processing as described above may be repeated.
- the power of increasing the processing delay by such repeated processing increases the effect of error correction in the decoding unit, and improves the reception characteristics.
- a stream reception quality estimation unit 7b for estimating the stream reception quality with respect to the output of the weighting unit 14 is provided separately, and the output of the stream reception quality estimation unit 7b is an error. It may be configured to output to the component estimation unit 15b.
- the error component estimation unit 15b instead of the stream reception quality estimation unit 7
- the error component power is estimated based on the output of the stream reception quality estimation unit 7b.
- likelihood information output is obtained as a soft decision value for each bit.
- MAP maximum posterior probability
- SOVA soft output Viterbi algorithm
- Max Log MAP decoder a stream reception quality estimation unit 7c for estimating the stream reception quality with respect to the output of the weighting unit 14 may be provided separately, and the output thereof may be output to the error component estimation unit 15c.
- the stream reception quality estimation unit 7c estimates the reception quality for each bit with respect to the bit data sequence before being input to the transmission path encoder 31 shown in FIG.
- a conversion process is performed to align the output order of the estimation unit 7c with the output order of the data to be weighted by the weighting unit 14.
- the error component estimation unit 15c uses the output of the stream reception quality estimation unit 7c as the reception quality estimation unit for all bits included in the symbol data.
- the processing shown in (Equation 21) is performed using the output data of 7c.
- the weighting unit 14 may individually calculate d (k) shown in (Equation 24) for the outputs of the two error component estimation units 13 and 15, and may perform weighting processing. Based on the result of further weighted synthesis of the outputs of the component estimation units 13 and 15, d (k) shown in (Equation 24) may be calculated and weighted.
- the configuration is complicated, it is possible to improve the reception characteristics by detecting error components by different calculation methods.
- FIG. 7 and 8 are diagrams showing a transmission configuration and a reception configuration of radio communication apparatus 100c in the fourth embodiment.
- the radio communication device 100c in FIG. 7 shows only the reception configuration, and the transmission configuration is shown in the radio communication device 100d in FIG.
- the reception configuration in the present embodiment shows a configuration in which iterative decoding is performed using a serial (sequential) interference canceller (SIC).
- SIC serial (sequential) interference canceller
- FIG. 8 differs from the configuration in FIG. 2 that is the transmission configuration in Embodiment 1 in the following points. That is, it has a plurality of transmission line encoders 21 and performs transmission line code processing independently for each spatially multiplexed stream transmitted from a plurality of antennas 26.
- the transmission operation of the wireless communication device lOOd will be described with reference to FIG.
- the wireless communication device lOOd transmits a plurality of M spatially multiplexed streams from a plurality (M, M> 1) of antennas 26-1 to M.
- M M
- M 2
- a transmission data generation unit (not shown) generates a bit data sequence z (k) to be transmitted to the radio communication device on the reception side.
- k represents a discrete time.
- Serial-parallel conversion means (SZP conversion means) 70 is a bit data sequence z that is a transmission data sequence.
- 21-m outputs a transmission bit data sequence d (k) obtained by performing error correction coding on the bit data sequence z (k) at a predetermined coding rate.
- Interleaver 23 performs an interleaving process on the transmission bit data sequence d (k).
- the modulation unit 24-m uses the predetermined multilevel modulation method for the output of the interleaver 23-m to map the transmission symbol sequence X mapped to the modulation symbols on the complex plane of the I signal and Q signal power. Output (k).
- Transmitter 25-m frequency-converts transmission symbol sequence X (k), which is a baseband signal, and also transmits antenna 26-m force as a high-frequency signal.
- X (k) which is a baseband signal
- antenna 26-m force as a high-frequency signal.
- m is a natural number less than or equal to M. Repeat the above operation for all m.
- the transmission symbol sequence at discrete time k transmitted from the m-th antenna cable is represented by X
- x (k) be a transmission symbol sequence at discrete time k at which a plurality of antenna (M> 1) forces are also transmitted.
- x (k) is an M-dimensional column vector
- the nth element is X (k) force.
- radio communication apparatus 100c The operation of radio communication apparatus 100c will be described using FIG. In the following, the operation after establishing frequency synchronization, phase synchronization, and symbol synchronization will be described.
- Nr multiple antennas 1l to Nr receive the transmitted high-frequency signals.
- Nr I a natural number greater than or equal to the number M of spatially multiplexed streams to be transmitted.
- the receiving unit 2-n performs a quadrature detection process on the high-frequency signal received by the antenna 1n, after amplification and frequency conversion processing (not shown), and a baseband signal composed of an I signal and a Q signal. Convert to In addition, the baseband signal is sampled as a discrete signal using AZD variations not shown.
- the received signal y (k) having the I signal and the Q signal sampled at the discrete time k as the real component and the imaginary component, respectively, is denoted. Also, y (k) is marked as the received signal at antennas l–l to Nr used for reception. y (k) is a column vector whose nth element is y (k) force.
- a received signal y (k) at wireless communication device 100c obtained in a flat fading propagation environment is ( It can be expressed as in equation 1).
- H represents the propagation path change received by transmission symbol sequence X (k) from radio communication apparatus lOOd.
- the propagation path fluctuation H is a matrix having (column number Nr of radio communication device 100c) row X (number of transmission antennas M in radio communication device lOOd) column power.
- the matrix element h of the i-th row and j-th column of the propagation path variation H indicates that the high-frequency signal that has also been transmitted by the j-th transmission antenna force in the wireless communication device lOOd is transmitted by the i-th antenna in the wireless communication device 100c. Shows changes in the transport path.
- n (k) represents a noise vector having NHS elements added at the time of reception by Nr antennas of radio communication apparatus 100c, and white noise with noise power ⁇ as shown in (Equation 2). And. Where I is an Nr-order identity matrix. E [x] represents the expected value of X.
- Channel estimation section 3 outputs a channel estimation value B, which is an estimation value for propagation path fluctuation H, using a known no-lot signal transmitted from radio communication apparatus lOOd.
- the signal separation unit 4 uses the channel estimation value B to obtain a spatial multiplexing separation weight for separating and receiving one spatial multiplexing stream from the transmission signals spatially multiplexed from the radio communication device lOOd. Generate and multiply the received signal y (k).
- the signal separation unit 4 performs the separation in descending order of reception SNR or reception SINR. Receiving ordering may be used. It is disclosed in Non-Patent Document 3 that the reception characteristics can be improved by this.
- the output signal after the multiplication operation by the signal separation unit 4 is output as a signal s (k) in which the amplitude and phase fluctuations due to the propagation path are equalized (hereinafter referred to as channel equalization).
- channel equalization the signal separation unit 4 compensates for the lack of information by receiving the received quality information q (k of the separated signal s (k). ) Is also output.
- the signal separation unit 4 uses ZF (Zero Forcing), MMSE (Minimum Mean Square Error) as the spatial multiplexing signal separation weight W for the desired transmission symbol sequence X (k).
- ZF Zero Forcing
- MMSE Minimum Mean Square Error
- W is a column vector having Nr elements
- T is a vector transpose.
- the output signal s (k) of the signal separation unit 4 is a symbol sequence (hereinafter referred to as a reception result) for a transmission symbol sequence that is symbol-mapped according to a predetermined multilevel modulation method in the modulation unit 24 on the transmission side. Symbol series).
- W when the ZF method is used can be expressed as an inverse matrix of the propagation path fluctuation estimation value B as shown in (Equation 4).
- Nr> M W uses the pseudo inverse matrix of the channel fluctuation estimation value B.
- the reception quality information q (k) uses the reception SNR or reception SINR of the reception symbol sequence s (k) obtained by signal separation.
- the received SNR or the received SI NR can be converted using the spatial demultiplexing weight W.
- the received quality information q (k) is the received SNR as shown in (Equation 5). A value based on the norm can be calculated.
- the demodulator 5-m performs a demapping process for converting the received symbol sequence s (k), which is the output of the signal separator 4, into a bit data string having a bit string power.
- the demodulator 5-m calculates the log likelihood ratio LLR as the likelihood information for each bit.
- demodulating section 5-m calculates likelihood information using (Equation 6) as log likelihood ratio LLR (k) of the i-th bit in received symbol sequence s (k). To do. Where L is send
- A is 0 or 1
- i is a natural number less than log (L).
- M is a natural number less than or equal to M.
- the output of demodulator 5 — m is input to first decoding processor 80.
- the first decoding processing unit 80 includes a Dintarino 60-m and a first decoding unit 62-m. The operation is described below.
- the Dinterleaver 60-m is opposite to the interleaving performed on the transmission side for the output of the likelihood information for each bit output from the demodulation unit 5-m (hereinafter referred to as the bit likelihood sequence).
- the bit data order is converted by the operation of.
- the first decoding unit 62-m performs error correction decoding processing on the bit likelihood sequence, which is a soft decision value output from the Dintarino 60-m, and uses a binary hard decision value.
- the tentatively determined bit data is output as a tentative determination bit string b (k) for the transmission bit data series.
- the second iterative decoding unit 90 includes a re-encoding modulation unit 8-2, a replica generation unit 92, an interference cancellation unit 10-2, a separation / combination unit 112, a likelihood calculation unit 12-2, and a null.
- Weight multiplication unit 75-2, error component estimation unit 76-2, weighting unit 142, and second decoding processing unit 80 (the following operations are performed.
- the re-encoding modulation unit 8-2 regenerates the transmission symbol data based on the temporary determination bit string b (k), and therefore includes a transmission path encoding unit, an interleaver, and a modulation unit (not shown). Including, the following processing is performed.
- the transmission path code key unit performs error correction coding on the temporary determination bit string b (k) according to a predetermined code rate and error correction method used at the time of transmission, and performs temporary determination transmission. Output as bit data series d [1] (k).
- the interleaver having the same interleave pattern used at the time of transmission performs an interleaving process on the provisionally determined transmission bit data sequence d [1] (k).
- the modulation unit uses the predetermined multilevel modulation used at the time of transmission for the output of the interleaver, and the provisional decision transmission symbol sequence x [1] mapped to the modulation symbols on the complex plane consisting of the I signal and Q signal power Output (k). Note that m is a natural number less than or equal to M.
- the replica generation unit 92 is a provisional decision transmission symbol that is an output of the recode modulation unit 8-2. Using the sequence x [1] (k) and the channel estimation value B output from the channel estimation unit 3, the replica signal y [1] (k ) Is generated. Where b is
- the interference cancellation unit 10-2 removes the mth spatial multiplexing stream from the reception signal y (k) that is the output of the reception unit 2 by regarding the mth spatial multiplexing stream as an interference signal. Outputs an interference cancellation signal V (k) from which interference is removed. That is, the interference cancellation unit 10-2 calculates the interference cancellation output V (k) as shown in (Equation 27).
- the interference cancellation output V (k) is a column vector with Nr elements.
- the interference cancellation output includes 1) only one spatial multiplexing stream or 2) the interference cancellation output includes a plurality of spatial multiplexing streams.
- the separation / combination unit 11-1 2 synthesizes and outputs the interference cancellation output V (k).
- Interference cancel output combining methods such as maximum ratio combining (MRC combining) and MMSE combining (least square error combining) can be applied.
- MRC combining maximum ratio combining
- MMSE combining least square error combining
- the combined output u (k) for the desired r-th spatial multiplexing stream is calculated as in (Equation 28).
- b is the r-th column vector in channel estimate B and superscript H is the vector conjugate transpose.
- r is a natural number less than or equal to M.
- the demultiplexing / combining unit 11-12 again performs signal separation processing on the plurality of spatial multiplexed streams excluding the m-th spatial multiplexed stream from which interference has been removed. At this time, a new channel estimation value B from which the channel estimation component from which interference has been removed is removed is used.
- channel estimation value B is a matrix of Nr rows (M ⁇ 1) columns excluding the m-th column vector of channel estimation value B.
- the demultiplexing / combining unit 11 1-2 separates one spatially multiplexed stream from the transmission signals transmitted from the wireless communication device lOOd in the same manner as the signal separating unit 4. Generates spatial demultiplexing weights to be received and performs multiplication on the received signal y (k).
- the demultiplexing / combining unit 11-12 may use ordering for demultiplexing and receiving in order of good reception SNR or reception SINR.
- the r-th spatial multiplexing stream is selected and received separately.
- r is a natural number less than or equal to M, excluding the mth interference cancelled.
- the output signal after the multiplication operation outputs a signal s (k) in which the amplitude and phase fluctuations due to the propagation path are equalized (hereinafter referred to as channel equalization).
- channel equalization a signal in which the amplitude and phase fluctuations due to the propagation path are equalized.
- only the channel-equalized signal lacks information on the received signal quality.
- the received quality information q (k) of the separated signal s (k) is also output. .
- the likelihood calculating unit 12-2 performs demapping processing for converting the combined output symbol data sequence u (k), which is the output of the separating / combining unit 11 1-2, into a bit data sequence composed of bit sequences.
- the log likelihood ratio LLR for each bit is calculated in the same manner as the demodulator 5.
- log likelihood ratio LLRr, i (k) as shown in (Equation 29) is calculated as reliability information for the i-th bit for the combined output symbol sequence ⁇ (k).
- L is the number of modulation multi-levels used at the time of transmission
- A is 0 or 1
- i is a natural number of log (L) or less.
- br is the number of channel estimates
- the rth column vector, r is a natural number less than or equal to M.
- Equation 29 describes the case where the maximum ratio synthesis method is applied to the separation / synthesis unit 11-2.
- the SNR criterion is used as the reception quality information q (k)
- the noise power in each antenna is omitted as common
- the received power II br II 2 is weighted by MRC combining for the rth spatial multiplexing stream. Is going.
- llxll 2 represents the norm for the solid X.
- the null weight multiplying unit 75-2 uses the spatial demultiplexing weight W used when the mth spatial multiplexing stream used in the signal demultiplexing unit 4 is separated and received as shown in (Equation 30).
- Equation 30 is a method that does not consider the received power of the mth spatial multiplexing stream on the assumption that the accuracy of the channel estimation value is sufficiently secured.
- the received power of the spatial demultiplexing weight used for separate reception instead of (Equation 30), the received power of the spatial demultiplexing weight used for separate reception
- a method using 8
- 2 may be used.
- the error component estimation unit 76-2 estimates the error component E (k) of the replica signal in the interference cancellation unit 10 based on the output of the null weight multiplication unit 75-2. That is, as shown in (Equation 31), the square of the absolute value of the output g of the null weight multiplier 75 is calculated.
- the calculated error component ⁇ (k) of the replica signal can detect the interference noise power component for the symbol data series at each discrete time k as follows in addition to the noise power ⁇ component: .
- the weighting unit 141-2 Based on the output of the error component estimation unit 76-2, the weighting unit 141-2 converts the error component into the bit likelihood sequence for the r-th spatially multiplexed symbol that is the output of the likelihood calculation unit 12-2. Correct according to.
- D (k) can be expressed as a function value using the noise power ⁇ added at the time of reception by the wireless communication device 100c and the output of the error component estimation unit 76-2 as parameters as shown in (Equation 33).
- the function shape reduces d (k) as the error component E (k) of the replica signal increases.
- the function shown in (Expression 34) is used.
- the output of the weighting unit 14-12 is input to the second decoding processing unit 80 ( 2) .
- the second decryption processing unit 80 is composed of the Dinterleaver 60 (-2, the second decryption unit 62 (, and has the same configuration as the first decryption processing unit 80.
- the second decoding unit 62 has an error correction decoding process on the bit likelihood sequence output from the Dinterleaver 60 ( — 2 and sends the binary hard decision value to the transmitted bit. Output as the decoding result of the data series.
- the wireless communication apparatus of the present invention includes ( ⁇ -1) iterative decoding units from the second iterative decoding unit 90 to the ⁇ -1. .
- the operation of the second iterative decoding unit 90 is as described above.
- the ⁇ -th iterative decoding unit 90— ⁇ performs the following operations. Where ⁇ is a natural number of 3 or more and ⁇ 1 or less.
- the re-encoding modulation unit 8- ⁇ regenerates transmission symbol data based on the provisional decision bit string for the m-th spatial multiplexed stream that is the output of the ⁇ -1 iterative decoding unit, It includes a transmission line code part, an interleaver, and a modulation part (not shown), and performs the following processing.
- the transmission path encoding unit performs a predetermined encoding rate used at the time of transmission on the temporary determination bit string. Then, error correction coding is performed by the error correction method, and the result is output as a provisional decision transmission bit data sequence d [n — 1] (k). Thereafter, interleaving processing is performed on the provisionally determined transmission bit data sequence d [n_1] (k) by an interleaver having the same interleaving pattern used at the time of transmission.
- the modulation unit uses the predetermined multilevel modulation used at the time of transmission for the output of the interleaver to map the provisional decision transmission symbol sequence x mapped to the modulation symbols on the complex plane having the I signal and Q signal powers.
- [n_1] (k) is output. Note that m is a natural number less than or equal to M.
- the replica generation unit 91-1 n is a temporary decision transmission symbol sequence x [n_1] (k) that is the output of the recode modulation unit 8-n and the channel estimation value B that is the output from the channel estimation unit 3. Is used to generate a replica signal y [1] (k) of the received signal y (k) as shown in (Equation 35). Where b
- m m represents the m-th column vector in channel estimate B.
- the interference cancellation unit 10—n receives the mth spatial multiplexing stream as an interference signal from V (k) that is the output of the interference cancellation unit 10— (n ⁇ 1) of the n ⁇ 1th iterative decoding unit. And the interference cancellation signal V (k) from which the mth spatial multiplexing stream has been canceled is output.
- the interference cancellation output V (k) is calculated.
- the interference cancellation output V (k) is a column vector with Nr elements.
- V (k) is the interference cancellation unit 10-2 of the second iterative decoding unit to the n-1 spatial multiplexed stream that has been subjected to interference cancellation by the interference cancellation unit 10 0-n of the nth iterative decoding unit.
- the interference cancel output V (k) includes M ⁇ (n ⁇ 1) spatial multiplexed streams.
- the demultiplexing / combining unit 111-1 n performs signal separation processing again on the plurality of spatial multiplexing streams excluding the spatial multiplexing streams from which interference has already been removed. Do. At this time, a new channel estimation value B obtained by removing the channel estimation component of the spatial multiplexing stream removed by the interference cancellation unit is used.
- B is a matrix with Nr rows (M ⁇ n + 1) columns.
- the spatial demultiplexing weight for demultiplexing and receiving one spatial multiplexed stream among the transmission signals spatially multiplexed from the wireless communication device lOOd is obtained.
- ordering may be used in which the reception SNR or reception SINR is good and the signals are separated and received in order of power.
- r-th spatial multiplexing stream is selected and received separately. Where r is a natural number less than or equal to M and the sky has already been cancelled. The index of inter-multiplexed streams is excluded.
- the output signal after the multiplication operation outputs a signal s (k) in which the amplitude and phase fluctuations due to the propagation path are equalized (hereinafter referred to as channel equalization). Also, since only the channel-equalized signal lacks information on the received signal quality, the received quality information q (k) of the separated signal s (k) is also output to compensate for this.
- the likelihood calculating unit 12-n performs a demapping process for converting the combined output symbol data sequence u (k), which is the output of the separating / combining unit 11-1n, into a bit data sequence composed of bit sequences.
- the log likelihood ratio LLR for each bit is calculated in the same manner as the demodulator 5.
- the null weight multiplication unit uses the spatial demultiplexing weight W used when the mth spatial multiplexing stream used in the demultiplexing / combining unit 10- (n-1) is separated and received.
- the output V (k) of the interference cancellation unit 10—n that is sequentially performed is equal to the received signal y ( By using k), a more accurate error component can be estimated.
- the error component estimation unit estimates the error component E (k) of the replica signal in the interference cancellation unit 10 based on the output of the null weight multiplication unit. In other words, the output of the null weight multiplication unit Calculate the square of the absolute value of the force gi .
- the weighting unit 14-1 n generates an error component in the bit likelihood sequence for the r-th spatially multiplexed symbol, which is the output of the likelihood calculating unit 13-n, based on the output of the error component estimating unit 13-n. Correct according to.
- the output of the weighting unit 14-1 is input to the n-th decoding processing unit 80 ⁇ .
- the ⁇ -th decoding processing unit 80 ⁇ is composed of a Dinterleaver 60 ⁇ and a ⁇ + 1 decoding unit 62 ⁇ , and has the same configuration as the first decoding processing unit 80. Omitted.
- the interference noise power is detected by using the error component at the time of interference cancellation using the received signal, the replica signal, and the spatial demultiplexing weight in the signal separation unit.
- the weighting unit 14 2 Based on the output of the error component estimation unit 76-2 that performs the operation, the weighting unit 14 2 corrects the likelihood information for the spatially multiplexed signal that is separated and combined after interference cancellation.
- interference cancellation includes a provisional determination output in which a determination error has occurred
- interference noise power is significantly included due to error factors such as channel estimation error and channel fluctuation error
- the bit for the received symbol Likelihood can be reduced, and as a result, by performing error correction decoding processing using those bit likelihoods, it is possible to suppress deterioration of reception characteristics.
- the hard canceller that uses the temporary decision value as the binary hard decision value which is the target of this embodiment, has a simpler configuration and better reception characteristics than the soft canceller that uses the soft decision value.
- Wireless communication device can be obtained.
- the output of the first decoding processing unit is output as a decoding result for the final transmission bit data sequence, and this output is again sent to re-encoding modulation unit 8-2. Then, the re-encoding modulation unit 8-2, the replica generation unit 92, the interference cancellation unit 10-2, the error component estimation unit 76-2, the separation / combination unit 11-2, the likelihood calculation unit 12-2, The weighting unit 14-2 and the second decoding processing unit 80 ( in this case, the same processing as described above may be repeated.
- the force decoding increases the processing delay by such repeated processing. This improves the error correction effect in the part and improves the reception characteristics.
- the present invention as the configuration on the transmission side, a plurality of transmission path codes are provided as shown in FIG.
- the configuration having the encoder 21 is shown, the present invention is not limited to this, and the present invention can be applied even when there is one transmission line encoder 21 as shown in FIG. That is, the likelihood information for each symbol, which is the output of the demodulator 5, is used to output the first tentative determination output and the nth likelihood calculator 12-n using the likelihood information for each symbol. Can be applied in the same way
- the configuration of the wireless communication apparatus that performs wireless communication using the single carrier modulation scheme has been described.
- the wireless communication apparatus that uses the multicarrier modulation scheme has been described.
- Application to is also possible.
- a multi-carrier modulation scheme using orthogonal frequency division multiplexing (OFDM) is often used. This is because the multi-nos delay of the radio propagation path is within the guard interval time. If this is the case, propagation path fluctuations received by each subcarrier can be handled as flat fading, so multinos equivalence processing is not required, and separation processing for signals that have been spatially multiplexed is reduced.
- OFDM orthogonal frequency division multiplexing
- the multicarrier modulation scheme is a transmission scheme using a plurality of subcarriers, and an input data signal to each subcarrier is modulated by M-value QAM modulation or the like to become a subcarrier signal.
- the frequency of each subcarrier has an orthogonal relationship, and by using a fast Fourier transform circuit, subcarrier signals with different frequencies are collectively converted to a time-axis signal, which is then converted to a carrier frequency band and converted from the antenna. Sent.
- the signal received from the antenna is converted into a baseband signal and subjected to OFDM demodulation processing.
- phase noise is added to the received signal.
- the carrier frequency error between transmission and reception can be suppressed by an automatic frequency control (AFC) circuit, but the residual carrier frequency error that is the error component remains.
- AFC automatic frequency control
- M-value QAM is used for subcarrier modulation
- data is judged by a decision circuit based on the absolute phase during demodulation, so if it undergoes phase rotation due to residual carrier frequency error or phase noise, a decision error is caused and reception characteristics deteriorate. .
- FIG. 12 shows an example of a transmission frame configuration including a pilot subcarrier signal.
- the transmission frame includes a training signal unit 50, a signaling unit 51, and a data unit 52.
- the PSC signal is included in a specific subcarrier.
- FIG. 13 is a diagram showing a configuration of the wireless communication device lOOj in the embodiment of the present invention including the phase tracking circuit 55 described above.
- the operation of the receiving unit 54 and the phase tracking circuit 55 which are components that are different from the configuration of FIG.
- Radio communication apparatus lOOj performs the following operation on signal transmitted by OFDM modulation with a transmission frame configuration as shown in FIG. First, using the received signal of the training signal unit 50, 1) automatic gain control (AGC) is performed to make the received signal level appropriate. 2) Subsequently, after frequency error correction by automatic frequency control (AFC), the OFDM demodulation section performs OFDM demodulation processing.
- AFC automatic gain control
- the OFDM demodulator outputs symbol data for each subcarrier.
- the channel estimation unit 3 calculates a channel estimation value indicating propagation path fluctuation for each subcarrier.
- the signal separation unit 4 performs signal separation processing based on the channel estimation value for each subcarrier.
- the subcarrier phase tracking circuit 55 performs the following operation with the channel-equalized data portion signal as an input.
- the PSC signal extraction unit 56 extracts the subcarrier signal power PSC signal of the equalized data part.
- the phase rotation detection unit 57 detects the phase rotation of the extracted PSC signal and the subcarrier signal after channel equalization of the replica signal power of the PSC signal.
- the phase compensator 58 compensates the detected phase rotation for the channel equalized subcarrier signal of the data part, and outputs it to the subsequent demodulator 5.
- the demodulator 5 determines a transmission symbol from a symbol data string based on a predetermined modulation scheme based on the information obtained by the signaling section, that is, the sign key modulation information of the transmission stream, and converts the symbol into a bit data string. Performs mapping processing and outputs likelihood information for each bit at the same time.
- the first decoding processing unit 6 uses the output result of the demodulating unit 5 to In addition, a Dinterleaver process that restores the bit order by an operation opposite to the interleaving performed on the transmission side, an error correction decoding process on the input bit data string, and a reception process that restores the transmission bit sequence Thus, a provisional determination output is obtained.
- the Dinterleaver can enhance the frequency diversity effect by including interleaving for the bit data string straddling different subcarriers. Subsequent processing is performed for each subcarrier by performing the operation in the above-described embodiment, so that the same effect as in the above-described embodiment can be obtained for the multi-carrier modulation method as well as the single-carrier modulation method. This comes out.
- the above operation causes a time-varying phase rotation due to residual carrier frequency error due to AFC error or sampling clock error in analog digital variation (A / D).
- phase compensation following phase rotation can be executed with a predetermined level of accuracy, and synchronous detection can be performed stably.
- the residual phase compensation error which cannot be corrected by the phase tracking circuit 55, may be insignificant.
- reception characteristics are significantly deteriorated.
- the error component estimator 13 can perform likelihood weighting for each subcarrier according to the magnitude of the remaining phase compensation error.
- the phase tracking circuit 55 performs the following operation because the PSC signal is received in a multiplexed state. That is, the phase rotation detection unit 57 generates a new phase tracking reference signal based on the output of the channel estimation unit 3 and the output of the PSC signal extraction unit 56, and detects the phase rotation. Then, the phase rotation detected by the phase compensation unit 58 is compensated. A detailed description of the configuration and operation is omitted.
- the radio communication apparatus has a reception diversity gain.
- Wireless communication field such as a radio base station device that performs spatial multiplexing transmission by a plurality of wireless communication devices, including a wireless communication device that transmits a plurality of signal sequences, and capable of sufficiently obtaining spatial multiplexing transmission Useful in.
- FIG. 15 is a diagram showing the configuration of radio communication apparatus lOOd in the fifth embodiment. Note that the radio communication device 100d in FIG. 15 shows only the configuration of the reception device, and the configuration of the transmission device is the same as the configuration shown in the radio communication device 100a in FIG.
- the configuration of the receiver in this embodiment performs iterative decoding using a parallel interference canceller.
- the difference from Embodiment 1 is that the output of the signal separation unit 4 is used to make a hard decision on the data mapped to the symbol, the hard decision unit 15, the hard decision result, the received signal, and the propagation path fluctuation estimated value.
- This is a point having an error estimation unit 16 and a first weighting unit 17 for estimating an error component using.
- a signal is received by receiving antenna 1 nr, and processing performed by radio section 2-nr, channel estimation section 3, signal separation section 4, demodulation section 5-m on the received signal is the same as in the first embodiment. Therefore, the explanation is omitted.
- Symbol hard decision section 15 receives reception symbol sequence s (k) output from signal separation section 4, selects a candidate signal point closest to the reception symbol point, and transmits the candidate signal point. Output as an estimate of the symbol.
- the symbol estimated value at discrete time k output from symbol hard decision section 15 is represented as xa (k)
- the symbol estimated values of a plurality of streams at discrete time k are represented as xa (k).
- xa (k) is an m-dimensional column vector.
- the error estimator 16 receives the baseband signal output from the receiver 2-nr, the channel fluctuation estimated value B output from the channel estimator 3, and the transmission symbol estimated output from the symbol hard decision unit 15. Using the values as inputs, the error component of the reception process is estimated from these inputs, and this error component is output.
- Error estimator 16 forces The following error factors can be identified from the output error components.
- Channel estimation error The channel estimator 3 uses the known symbols included in the received data to calculate the estimated channel fluctuation from the transmitting antenna to the receiving antenna.
- an error occurs in B shown in (Equation 40), resulting in an error in replica signal ya (k), and error component E (k) shown in (Equation 41). An error in the estimated channel fluctuation value appears.
- the first weighting unit 17 receives the likelihood LLR as the output of the demodulator 5—m and the error component E (k) as the output of the error estimation unit 16, and corrects the likelihood LLR with the error component. Then, the corrected likelihood LLR is output.
- the likelihood output from the demodulator 5-m is the log-likelihood ratio LLR for each bit.
- the log likelihood ratio LLR is calculated by (Equation 42).
- s (k) is the received symbol sequence
- L is the modulation multi-level number used during transmission
- A is 0 or 1
- i is a natural number less than log (L)
- q (k) represents reception quality information.
- the likelihood LLR calculated in (Equation 42) is multiplied by the error correction value d (k), and the corrected likelihood that is the output of the first weighting unit 17 is obtained.
- the error correction value d (k) is represented by the error estimated value E (k) and the noise power added at the time of reception by the wireless communication device 100d as shown in (Equation 44).
- the first decoding processing unit 6 receives the likelihood LLR that is the output of the first weighting unit 17, performs the same processing as in Embodiment 1, and outputs the decoding result. Operation of the first decryption processing unit 6 Since the operation is the same as in the first embodiment, the description thereof is omitted. In FIG. 15, since the operations until obtaining the decoding result from the second decoding processing unit 6 ( 2) performed in each block indicated by reference numerals 8 to 14 and 6 (in FIG. 15 are the same as those in the first embodiment. The description is omitted.
- the first decoding processing unit 6 in FIG. 15 is omitted, and the output of the signal separation unit 4 is hard-decided as shown in the wireless communication device lOOe shown in FIG. 16, and the result is used.
- a configuration that generates a replica signal is also conceivable. According to this configuration, although the reception characteristics deteriorate, the following problems in iterative decoding can be solved.
- the replica generation unit 9 receives as input the hard decision result (provisional decision output) of the symbol hard decision unit 15 and the channel fluctuation estimation value from the channel estimation unit 3, and the replica generation unit 9 of FIG. The same processing is performed and the symbol hard decision result is output. Thereafter, the same processing as in FIG. 15 is performed on each block indicated by reference numerals 13 to 14 and 6 (2) in the figure to obtain a decoding result.
- FIG. 17 shows the configuration of radio communication apparatus lOOf in the sixth embodiment. Note that the radio communication device 100f in FIG. 17 shows only the configuration of the receiving device, and the transmitting device is the same as the configuration shown in FIG.
- the radio communication device lOOf shown in the present embodiment relates to an iterative decoding receiver using a parallel interference canceller.
- FIG. 17 the difference from Embodiment 1 (FIG. 1) is that the first likelihood that the likelihood LLR of the output of the weighting unit 14 m is corrected using the likelihood that is the output of the demodulation unit 5-m.
- the correction unit 18 is included.
- the present invention is not limited to this.
- a signal received by antenna 1 nr is received by receiving section 2-m, channel estimating section 3, signal separating section 4, demodulating section 5-m, first decoding processing section 6, and re-encoding modulation.
- the operations from the output of the likelihood LLR from the unit 8, the replica generation unit 9, the interference cancellation unit 10, the separation / synthesis unit 11m, the likelihood calculation unit 12-m, the error component estimation unit 13, and the weighting unit 14 are performed. Since this is the same as the first embodiment, the description thereof is omitted.
- the first likelihood correction unit 18 receives the likelihood LLR that is the output of the demodulation unit 5-m and the weighted likelihood LLR that is the output of the weighting unit 14 as inputs. Is added and the added likelihood LLR is output.
- the likelihood LLRa is calculated by adding the likelihood calculated by (Equation 6) and the likelihood calculated by (Equation 13).
- the second decoding processing unit 6 (the likelihood LLRa output from the first likelihood correction unit 18 is input, the same processing as the first decoding processing unit 6 is performed, and the decoding result is output. Since the operation of the second decryption processing unit 6 (is the same as that of the first embodiment, its description is omitted.
- the following effects can be obtained. That is, interference cancellation Even if the correct decoding result of the first decoding processing unit 6 is obtained by canceling the interference component by the replica signal generated using the wrong temporary determination output in the error unit 10, the symbol determination error is not detected. Power that may cause error propagation According to the configuration according to the present embodiment, the likelihood LLR input to the first decoding processing unit 6 and the LLR of the bit in which error propagation has occurred are added. In the second decoding processing unit 6 ( , the occurrence of errors can be suppressed and the performance degradation can be suppressed.
- the power obtained by adding the likelihood LLR output from the demodulation unit 5-m and the likelihood LLR output from the weighting unit 14 is not limited to this. You can do it.
- the output of the first likelihood correction unit 18 outputs LLR (k) when LLR (k) is larger than LLR [1] (k), as shown in (Equation 47), LLR [1] (,
- LLR [1] (k) is output.
- the likelihood output from the first likelihood correction unit 18 is input to the second decoding processing unit 6 (2) , performs the same processing as in Embodiment 1, and outputs the decoding result.
- the likelihood LLR output from the demodulator 5-m and the likelihood LLR output also from the weighting unit 14 are more likely to be correctly decoded! since the input to the second decoding processing unit 6 (2), can be decoded result output from the second decoding processor 6 (2) is prevented from you degradation.
- the first likelihood correction unit 18 when a CRC (Cyclic Redundancy Check) code is assigned to each transmission stream, an output is made based on the CRC check result. It is also possible to select likelihood information.
- CRC Cyclic Redundancy Check
- the likelihood information that can be decoded without error based on CRC can be input to the second signal processor 6 (2). And the deterioration of the decoding result output from the second decoding processing unit 6 (2) can be suppressed.
- Figure 18 shows the configuration of the receiver in this case.
- the operation up to the output of the signal received by antenna 1 nr until receiving unit 2-nr, channel estimating unit 3, signal separating unit 4, demodulating unit 5-m force likelihood LLR is shown in this embodiment. Since this is the same, the description thereof is omitted.
- the symbol hard decision unit 15, the error estimation unit 16, and the first weighting unit 17 are the same as the configuration for error estimation described in the fifth embodiment. These are added to the wireless communication device lOOf described above.
- the symbol hard decision unit 15 receives the received symbol sequence s which is the output of the signal separation unit 4
- the input signal (k) is input, and a hard decision is made by estimating the point where the distance between the transmission signal point mapped on the complex plane of the I signal and the Q signal and the input reception symbol sequence is the transmission signal point. Output points.
- the error estimator 16 includes the hard-decided signal point output from the symbol hard-decision unit 16, the baseband signal output from the receiver 2-nr, and the propagation path output from the channel estimator 3. Using the fluctuation estimation value as input, the error component is estimated by subtracting the replica signal created using the symbol hard decision value and the channel fluctuation estimation value from the baseband signal, and the estimated error component is Output.
- the first weighting unit 17 receives the estimated error component and the likelihood LLR output from the demodulating unit 5-m, and weights the likelihood LLR according to the noise component, and the weighted likelihood. Outputs LLR. Since the detailed operation of these processes is the same as that of the fifth embodiment, the description thereof is omitted.
- the weighted likelihood LLR output from the first weighting unit 17 is the first decoding process. Input to the unit 6 and the first likelihood correction unit 18. The operations after the first decryption processing unit 6 are the same as those in FIG. 17 of the present embodiment. Therefore, the description is omitted.
- the received symbol sequence is hard-decided when estimating the error component, performance degradation occurs compared to the case of soft-decision and decoding, but it can be configured with a simple arithmetic circuit.
- the circuit scale can be kept small.
- FIG. 19 shows the configuration of radio communication apparatus lOOg according to the seventh embodiment.
- Figure 19 shows
- the wireless communication device lOOg shown in the present embodiment includes a serial (sequential) interference canceller (SIC).
- SIC serial (sequential) interference canceller
- FIG. 19 differs from FIG. 7 in Embodiment 4 in that the symbol hard decision unit 15 that makes a hard decision on the received symbol sequence after signal separation, the received baseband signal and the hard decision value, and the propagation path change An error estimation unit 16 that estimates an error component using the estimated value and a first weighting unit 17 that corrects the likelihood LLR according to the estimated error component are included.
- the parts different from FIG. 7 of the fourth embodiment will be mainly described with reference to FIG. 19, and the description of the same configurations will be omitted.
- the received signal received by the receiving antenna 1 nr is processed by the receiving unit 2-nr, channel estimating unit 3, signal separating unit 4, demodulating unit 5-m until the likelihood LLR is output. Since this operation is the same as that of FIG.
- the symbol hard decision unit 15 determines the received symbol sequence s (k) output from the signal separation unit 4. As an input, the received signal is hard-decided, and the hard-decided signal point is output as an estimated value of the transmission symbol.
- the hard decision is the distance between the signal point on the complex plane of the equalized received symbol sequence s (k) from the candidate signal points on the complex plane that also have the transmitted I signal and Q signal power. Is selected as the estimated value of the transmission symbol.
- the estimated value of the transmitted symbol at discrete time k is expressed as xa (k).
- the error estimation unit 16 receives the received baseband signal y (k), the channel fluctuation estimation value B output from the channel estimation unit 3, and the transmission symbol estimation value xa (k) output from the symbol hard decision unit 15. Then, the spatial demultiplexing weight W used in the signal demultiplexing unit 4 for taking out the m-th spatial multiplexed stream (not shown) is input, the error component due to the reception process is calculated, and the error component is output. A method for calculating the error component will be described below.
- a replica signal ya (k) is created using the input transmission symbol estimation value xa (k) and the channel estimation value B.
- b is the channel fluctuation estimate B
- va (k) is multiplied by the spatial demultiplexing weight W used to extract the mth spatially multiplexed stream, and the error component E (k) is estimated.
- the error component E (k) can detect the interference noise power component of the received symbol sequence at the discrete time k as follows in addition to the noise power ⁇ .
- Channel estimation error The channel estimation unit 3 uses a known symbol included in the received data to calculate a propagation path fluctuation estimation value from the transmission antenna to the reception antenna. If the estimated channel fluctuation calculated at this time deteriorates, an error occurs in b shown in (Equation 48), resulting in an error in the replica signal ya (k), and the error component shown in (Equation 49). An error in the estimated channel fluctuation appears in E (k).
- the first weighting unit 17 receives the likelihood LLR output from the demodulation unit 5-1 and the error component output from the error estimation unit 16, and corrects the likelihood LLR according to the error component. Outputs the corrected likelihood LLR.
- the corrected likelihood LLRa [1] (k) is calculated by the product of the likelihood LLR and the correction value d (k).
- the correction value d (k) can be expressed by a function including parameters of the noise power ⁇ and the error component E (k) in the wireless communication device lOOg, and the value of E (k) The value of d (k) becomes smaller when E becomes larger. The value of d (k) becomes larger when E (k) becomes smaller.
- An example of d (k) is shown in (Formula 52).
- First decoding processing unit 80 receives likelihood LLR output from first weighting unit 17, performs the same processing as in Embodiment 4, and outputs the first provisional determination value. . Thereafter, the second iterative decoding unit 90 and the third iterative decoding unit perform the same processing as in the fourth embodiment, and obtain a third determination output.
- the error estimation unit 3 uses the hard decision value of the reception signal, the reception signal, and the channel estimation value as the error generated by the channel estimation unit 3 and the nodeware. Based on this, the first weighting unit 17 corrects the likelihood LLR input to the first decoding processing unit 80 based on this.
- the symbol input to the first decoding processing unit 80 can be reduced based on the estimated value of the noise component, and as a result, by performing decoding processing using this likelihood, it is possible to suppress degradation of reception characteristics.
- the interference cancellation unit 10-2 in the second iterative decoding unit 90 has an error. Performance degradation caused by canceling interference with a replica signal can be suppressed. As a result, performance degradation after the second iterative decoding unit 90 can be suppressed.
- FIG. 20 shows a configuration of radio communication apparatus 100h according to the present embodiment. Note that FIG. 20 shows only the receiving device, and the transmitting device is the same as in FIG.
- Radio communication apparatus 100h shown in the present embodiment relates to an iterative decoding receiver using a parallel interference canceller (PIC).
- Figure 20 shows how the wireless communication device 1 OOh operates. explain.
- Embodiment 5 the difference from Embodiment 5 (FIG. 15) is that the bit selection unit 18 and the modulation method of the received frame for performing the approximate calculation of normalization by ⁇ shown in (Equation 45) are specified. Yes The modulation scheme specifying unit 20 is included. Further, the weighting unit 19 obtains the calculation result of the division circuit by referring to the table in order to simplify the circuit for obtaining the correction value from the error component.
- Receive signal is received by receiving antenna 1 nr, and error value is output from receiver 2-nr, channel estimator 3, signal separator 4, demodulator 5-m, symbol hard decision unit 15, error estimator 16 Since the operation up to this point is the same as that of the fifth embodiment, the description of the operation is omitted.
- the bit selector 18 receives the error value E (k) output from the error estimator 16 and a control signal indicating the current modulation method, and the control signal indicates as shown in (Formula 53). Error value E (k) is multiplied by c for each modulation method, and error value Ea (k) multiplied by c is output.
- c is a value that changes according to the value of the control signal.
- Figure 21 shows an example of the output value of c for the control signal input.
- the control signal changes according to the modulation method of the received packet.
- the input control signal will be described later.
- the control signal may be a coding rate of coding performed on the transmission side, not limited to the modulation method.
- a signal that combines a modulation method and a coding rate is also acceptable.
- Figure 23 shows the table reference ROM (Read Only Memory) used in the calculation of d (k).
- the error value Ea (k) is input to this ROM, and the calculation result of d (k) is obtained.
- the input range of error values shall be 1 or less. If a value of 1 or more is input, 1 shall be output.
- the first decoding processing unit 6 uses the corrected likelihood LLR output from the weighting unit 19 as an input, performs processing such as dingtery and error correction decoding for rearranging the data series, and performs the first decoding processing.
- the temporary judgment result that is the decoding result of part 6 is output. Since the configuration of the first decoding processing unit 6 is the same as that of the fifth embodiment, description of the operation thereof is omitted.
- Temporary decision output is re-encoded modulation unit 8, replica generation unit 9, interference cancellation unit 10, demultiplexing Since the configuration from the generation unit 11 1, the likelihood calculation unit 12-1, and the error component estimation unit 13 is the same as that of the fifth embodiment, description of the operation is omitted.
- the bit selection unit 18 (2) receives the error component output from the error component estimation unit 13 and the control signal, performs the same processing as the bit selection unit 18, and outputs the result. Since the operation of the bit selection unit 18 (2 ) is the same as that of the bit selection unit 18, the description thereof is omitted.
- the weighting unit 19 (is input to the likelihood LLR output from the likelihood calculating unit 12-1 and the error component output from the bit selecting unit 18 ( 2) , and the likelihood LLR is the same as the weighting unit 19 And outputs the result.
- the operation of the weighting unit 19 is the same as that of the weighting unit 19, and thus the description thereof is omitted.
- the training unit 22-1 is a known symbol and is used for frame synchronization, frequency synchronization, sampling phase synchronization, channel estimation, and the like.
- the signaling unit 22-2 is a symbol modulated by a known modulation scheme, for example, BPS K, and is a symbol for indicating in which modulation scheme the subsequent data unit 22-2 is modulated.
- the data part 22-3 is a symbol obtained by modulating the data to be communicated.
- the modulation scheme specifying unit 20 shown in Fig. 20 receives the decoding result output from the first decoding processing unit 6 as input, decodes the signaling unit 22-2 of the received signal, and stores the data in the data unit 22-3.
- the modulation method is specified, and the specified modulation method is output as a control signal. Modulation methods can be classified by mapping methods such as BPS K, QPSK, 16QAM, and 64QAM.
- the encoding method can be classified by the encoding rate of the error correction code applied on the transmission side.
- the coding rate is changed by puncturing the bit sequence of the coding rate 1Z2 output from the convolutional encoder.
- the bit selection unit 18 and the bit selection unit 18 calculate the error component according to the modulation scheme specified by the modulation scheme specification unit 20. Then, the weighted likelihood LLR is decoded using the result.
- the error component is multiplied by the value set for each modulation method and coding rate. Since the likelihood LLR can be corrected using an optimal correction value for each modulation scheme and code rate, the degradation of the decoded output can be suppressed as a result.
- the normality ⁇ based on the noise power ⁇ of the fifth embodiment is configured by bit shift, and the function of the division circuit is realized by referring to the table.
- the circuit scale of the circuit added to can be reduced.
- bit selection unit 18 and the weighting unit 19 described in this embodiment are provided with the weighting unit 14 or the first weighting unit 17 in the drawings in all the embodiments of this specification. You can get away with it.
- the present invention has an effect of suppressing degradation of reception characteristics even when an error is included in a transmission signal replica, and is useful for a radio communication apparatus that performs iterative decoding reception of a signal.
Abstract
Description
Claims
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EP2254270A4 (en) * | 2008-03-13 | 2016-01-20 | Nec Corp | RECEIVING DEVICE AND METHOD |
JP5318091B2 (ja) * | 2008-04-18 | 2013-10-16 | シャープ株式会社 | 受信装置および通信システム |
WO2009128417A1 (ja) * | 2008-04-18 | 2009-10-22 | シャープ株式会社 | 受信装置および通信システム |
US8446999B2 (en) | 2008-04-18 | 2013-05-21 | Sharp Kabushiki Kaisha | Receiving apparatus and communication system |
WO2010010867A1 (ja) * | 2008-07-22 | 2010-01-28 | 日本電信電話株式会社 | 受信方法、及び、受信装置 |
JP5558355B2 (ja) * | 2008-07-22 | 2014-07-23 | 日本電信電話株式会社 | 受信方法、及び、受信装置 |
US8516328B2 (en) | 2008-07-22 | 2013-08-20 | Nippon Telegraph And Telephone Corporation | Reception method and reception device |
JP2011109278A (ja) * | 2009-11-13 | 2011-06-02 | Nippon Telegr & Teleph Corp <Ntt> | 受信装置及び受信方法 |
JP2011119844A (ja) * | 2009-12-01 | 2011-06-16 | Nippon Telegr & Teleph Corp <Ntt> | 無線通信システム、送信装置、受信装置、無線通信方法及びプログラム |
CN102013910B (zh) * | 2010-11-17 | 2013-12-04 | 中国人民解放军理工大学 | 一种短波多天线信号增强接收方法 |
CN102013910A (zh) * | 2010-11-17 | 2011-04-13 | 中国人民解放军理工大学 | 一种短波多天线信号增强接收方法 |
JP2014116933A (ja) * | 2012-11-15 | 2014-06-26 | Nippon Telegr & Teleph Corp <Ntt> | 受信装置及び受信信号処理方法 |
JP2021141454A (ja) * | 2020-03-05 | 2021-09-16 | 株式会社東芝 | 受信装置、送信装置、受信方法および送信方法 |
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US20090125793A1 (en) | 2009-05-14 |
JP5030279B2 (ja) | 2012-09-19 |
US8261169B2 (en) | 2012-09-04 |
CN101449502A (zh) | 2009-06-03 |
CN101449502B (zh) | 2012-11-07 |
JP2007336532A (ja) | 2007-12-27 |
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