JP4549162B2 - Radio base station apparatus and radio communication method - Google Patents

Description

  The present invention relates to a radio base apparatus that includes a radio terminal apparatus that transmits a plurality of signal sequences and performs spatial multiplexing transmission using the plurality of radio terminal apparatuses, and a radio communication method using the same.

  In recent years, there has been a great increase in demand for higher capacity and higher speed of wireless communication, and research on methods for further improving the effective utilization efficiency of limited frequency resources has become active. As one of the methods, a technique using a spatial domain is attracting attention. One of the spatial domain utilization techniques is an adaptive array antenna (adaptive antenna), which adjusts the amplitude and phase by a weighting coefficient (hereinafter, this weighting coefficient is referred to as “weight”) to be multiplied with a received signal, thereby obtaining a desired direction. By strongly receiving a signal arriving from and directing nulls in the direction of the interference wave, it is possible to suppress the interference wave, thereby improving the communication capacity of the system.

  Further, as another technique using the spatial domain, by using spatial orthogonality in the propagation path, different data sequences can be obtained by using physical channels of the same time, the same frequency, and the same code. (1) Different terminals There are a space division multiple access (hereinafter referred to as SDMA) technology for transmission to a device, and (2) a spatial multiplexing (hereinafter referred to as SDM) technology for transmission to the same terminal device. The 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, improving the throughput of the wireless communication system and the number of simultaneous users accommodated. be able to. In this case, the reception method of the base station apparatus at the time of transmission from the terminal apparatus to the base station apparatus (uplink) is disclosed in Non-Patent Document 2, for example, and transmission sequences from a plurality of wireless terminal apparatuses are MMSE. Separate reception is possible using techniques such as (Minimum Mean squared error), ML (Maximum Likelihood), and SIC (Successive Interference Cancellation).

On the other hand, SDM technology, for example, is disclosed in Non-Patent Document 3, and a transmitter and a receiver are provided with a plurality of antenna elements, and SDM transmission is realized in a propagation environment in which the correlation of received signals between antennas is low. it can. In this case, different data sequences and different data sequences are transmitted from the plurality of antennas included in the transmitter using physical channels having the same time, the same frequency, and the same code for each antenna element, and the receiver includes a plurality of antennas included in the receiver. The received signal is separated from the received signal at the antenna based on different data series. Thereby, it is possible to achieve high speed without using multilevel modulation by using a plurality of spatial multiplexing channels. When performing SDM transmission, in an environment where there are many scatterers between transmitters and receivers under sufficient S / N (signal-to-noise ratio) conditions, the transmitter and receiver must have the same number of antennas. The communication capacity can be increased in proportion to the number of antennas.
T. Ohgane et al, "A study on a channel allocation scheme with an adaptive array in SDMA," IEEE 47th VTC, Page.725-729, vol.2 (1997) P.Vandenameele, "A Combined OFDM / SDMA Approach," IEEE J. on Selected Areas in communications, Vol.18, No.11, Nov. 2000 GJFoschini, "Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas," Bell Labs Tech. J., pp.41-59, Autumn 1996

When performing wireless communication from a plurality of wireless terminal apparatuses to a wireless base station apparatus using the SDMA method, if at least one of the plurality of wireless terminal apparatuses includes a wireless terminal apparatus that transmits a plurality of signal sequences, conventional SDMA separation Although separate reception is possible depending on the reception method, the following problems arise.

  (1) When a linear separation method such as MMSE or SIC is used, if the transmission sequences are subjected to space-time coding, separation for each transmission sequence is given priority, so that a sufficient diversity effect cannot be obtained.

  (2) In the case of SIC, since decoding processing is sequentially performed for each transmission sequence, a buffer memory for primary storage is necessary until all signal sequences of the wireless terminal device are processed, and different tolerances are provided for each wireless terminal device. It becomes difficult to cope with QoS (Quality of Service) such as delay.

  (3) When MLD is used, the amount of computation increases exponentially as the number of connected wireless terminal devices and the number of modulation multilevels increase.

  The present invention solves the above-mentioned problems, and can effectively obtain a diversity effect and a coding gain, reduce a required amount of buffer memory for primary storage, and easily cope with QoS. An object is to provide an apparatus and a wireless communication method.

  In addition, even when the correlation between transmission signals is high, the effect of processing such as spatio-temporal interleaver and spatio-temporal phase rotation that lowers the correlation between multiple transmission signals is effectively utilized, and the constraint conditions during channel allocation are relaxed, An object of the present invention is to provide a radio base station apparatus and a radio communication method capable of introducing a simple scheduler.

  In order to solve the above-described conventional problems, the present invention provides a plurality of radio terminals in a radio base station apparatus that separately receives a plurality of signal sequences spatially multiplexed from a plurality of radio terminal apparatuses using a plurality of antennas. At least one of the devices includes a wireless terminal device that transmits a plurality of signal sequences, and a received signal sequence of a desired wireless terminal device obtained by removing signal sequence components excluding the desired wireless terminal device from signals received by a plurality of antennas. Other user signal removal means for extracting and individual user reception processing means for performing reception processing for each user based on the output of the other user signal removal means.

  According to the radio base station apparatus of the present invention, in a radio base station apparatus that enables separate reception of a plurality of transmission sequences from a plurality of terminal apparatuses, a diversity effect and a code for a plurality of transmission sequences subjected to space-time codes The gain can be effectively obtained. Further, by improving the conventional SIC, it is possible to reduce the required amount of buffer memory for primary storage and to easily cope with QoS. In addition, even when the correlation between transmission signals is high, the effect of processing such as a spatio-temporal interleaver or spatio-temporal phase rotation that lowers the correlation between a plurality of transmission signals can be effectively used. As a result, the restriction condition at the time of channel allocation can be relaxed, and the effect that a simple scheduler can be introduced can be used effectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a radio base station apparatus according to Embodiment 1 of the present invention. Hereinafter, in the present embodiment, an operation of the radio base station apparatus at the time of transmission (hereinafter, uplink) from a plurality of radio terminal apparatuses to the radio base station apparatus will be described.

  In FIG. 1, 1-1 to 1-Nt (showing the case of Nt = 2 in the figure) are wireless terminal devices, and 2 is a wireless base station device (in the following description, when wireless terminal devices are collectively referred to) (Referred to as wireless terminal device 1). In the radio base station apparatus 2, 3 is a plurality (NR pieces) of antennas, and 4-1 to 4 -Nt (shown in the figure is a case of Nt = 4) are the respective high frequency signals received by the plurality of antennas 3. A receiving unit that converts the frequency into a baseband signal and extracts it as a digital signal (in the following description, when the receiving unit is generically referred to as a receiving unit 4), 5 uses a plurality of radio terminal apparatuses 1-1 to 1-Nt. Other user signal separation means 6-1 to 6-Nt (Nt = 2 is shown in the figure) for outputting an inter-user interference cancellation signal from which interference between users is eliminated for a plurality of transmission sequences to be transmitted. ) Is a user individual reception processing means for performing reception processing on a transmission sequence in units of users from the inter-user interference cancellation signal (in the following description, the user individual reception processing means is collectively referred to as user individual reception processing means 6). It is. Hereinafter, the operation will be described in order with reference to FIG.

First, Nt radio terminal apparatuses 1-1 to 1-Nt each transmit a transmission sequence from an antenna. Here, the transmission sequence at the discrete time k transmitted from the nth radio terminal apparatus 1-n to the radio base station apparatus 2 is denoted as x _n (k). n is a natural number equal to or less than Nt, and when a plurality of M (n) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n)> 1), a transmission sequence x _n ( k) consists of a column vector of M (n) dimensions.

FIG. 2 is a diagram illustrating a detailed configuration of the wireless terminal device 1. 2A illustrates a case where the wireless terminal apparatus 1 performs transmission using a single antenna, and FIG. 2B illustrates a case where transmission is performed using a plurality of antennas (in the drawing, M (n) = 2 is shown as an example). The configuration is shown. In FIG. 2, the data sequence generation means 20 generates a data sequence z _n to be transmitted to the radio base station apparatus 2.

In the case of single antenna transmission in FIG. 2A, the data sequence z _n generated by the data sequence generation means 20 is regarded as a transmission sequence x _n (k), and the transmission path encoding means 22-1 uses a predetermined coding rate. After performing error correction coding, interleaving is performed by an interleaver 23-1, and a baseband signal in which a bit string is mapped to a modulation symbol on an IQ plane using a predetermined multilevel modulation by a modulation unit 24-1 is transmitted. The unit 25-1 converts the frequency of the baseband signal, adds a band limiting process, and transmits the amplified signal as a high frequency signal from the antenna after amplification.

On the other hand, in the case of multi-antenna transmission in FIG. 2B, the data sequence z _n generated by the data sequence generation means 20 is converted into M (n) parallel data strings by the serial / parallel conversion means (S / P conversion means) 21. Conversion to a certain transmission sequence x _n (k). That is, the transmission sequence x _n (k) is represented as a column vector having M (n) elements. Thereafter, for each transmission sequence, transmission path encoding means 22-1 to 22-M (n), interleavers 23-1 to 23-M (n), modulation means 24-1 to 24-M (n), and transmission The units 25-1 to 25-M (n) perform the same processing as the single antenna transmission. It is also possible to transmit using a larger number of antennas than the transmission sequence. In this case, a method of multiplying the transmission sequence by a directivity weight forming a desired directivity, or STBC (Space Time This can be realized by applying space-time coding such as (Block coding). Hereinafter, a case will be described in which the number of antennas used for transmission in the wireless terminal device 1 is the same as the number of transmission sequences.

  Next, the operation in the radio base station apparatus 2 will be described using FIG. In the following, operations after establishing frequency synchronization, phase synchronization, and symbol synchronization will be described. The high-frequency signals received by the Nr multiple antennas 3 are orthogonally detected after amplification and frequency conversion (not shown) in the reception units 4-1 to 4-Nr, respectively, and converted into baseband signals on the IQ plane. Further, it is output as a received signal y (k) expressed by a complex digital signal using an A / D converter. Here, y (k) is a column vector including as elements the received signals with Nr antennas used for reception.

Here, with respect to the transmission sequence x _n (k) from the radio terminal apparatus 1-n, the received signal y (k) at the radio base station apparatus 2 at the discrete time k obtained in the flat fading propagation environment is ). In (Equation 1), H _n indicates the propagation path variation received by the transmission sequence x _n (k) of the n-th radio terminal apparatus 1-n, and (the number of radio base station antennas Nr) rows × (the n-th radio terminal device 1-n). This is a matrix composed of M (n)) columns of transmission antennas in the wireless terminal device 1-n, and the matrix element h _ij of i rows and j columns is the jth transmission in the nth wireless terminal device 1-n. When the signal transmitted from the antenna is received by the i-th antenna in the radio base station apparatus 2, the propagation path variation due to the propagation path is shown. N (k) represents a noise vector having Nr elements added at the time of reception by the Nr antennas of the radio base station apparatus 2.

Next, the other user signal separation means 5 estimates the propagation path fluctuation with respect to the propagation path fluctuation H _n estimated using a known pilot signal transmitted from the radio terminal apparatus 1-n (n is a natural number equal to or less than Nt). An inter-user separation weight for separating other user signals from different radio terminal apparatuses 1-m (m ≠ n) is generated using the value B _n, and a multiplication operation is performed on the received signal y (k). Where the user isolation weights for the desired n-th radio terminal apparatus 1-n W _n, as shown in equation (2), the propagation path fluctuation estimation excluding the desired n-th radio terminal apparatus 1-n A matrix G (n) composed of values B _j (where j ≠ n) is generated using singular value decomposition. ^{H in} (Expression 2) is an operator that performs complex conjugate transposition. That is, among the column vectors (left singular vectors) u _j constituting the left singular matrix U of the propagation path fluctuation estimated value G (n), the radio terminal apparatus 1-j excluding the desired n-th transmission transmits a total of Ms pieces. When a sequence is transmitted and the number of receiving antennas is Nr, j = (Ms + 1),..., Nr (Nr−Ms) left singular vectors u _j are selected. As shown in (Expression 3), the selected left singular vector u _j is used as an inter-user separation weight matrix W _n . Each selected left singular vector u _j becomes a weight for directing a directivity null to the transmission signal excluding the transmission sequence x _n (k) from the desired nth radio terminal apparatus 1-n. In order to generate the separation weight between users, it is necessary to satisfy the condition of (the number of all transmission sequences from all wireless terminal devices 1) ≦ (the number of antennas Nr of the number of wireless base stations).

By using the inter-user separation weight W _n generated in this way, the received signal y (k) at the radio base station apparatus 2 is multiplied as shown in (Equation 4), so that another radio terminal apparatus is obtained. A signal y _n (k) with reduced interference signal components from 1-m can be obtained. Nt Also, when channel estimation is ideally performed, a relationship such as (Equation 5) is obtained, so (Equation 4) can be modified as shown in (Equation 6), and y _n ( k) is a signal from which the interference signal component from the other radio terminal apparatus 1-m is completely removed. In other words, the other user signal separating means 5 acts as a user signal removing means for removing a signal from another user from the other wireless terminal apparatus 1-m.

Next, the individual user reception processing means 6 performs individual user reception processing on the other user signal separation signal y _n (k). FIG. 3 is a diagram showing a configuration of user individual reception processing means 6-n that receives a transmission sequence from the nth radio terminal apparatus 1-n. In the nth radio terminal apparatus 1-n, when the number of transmission sequences M (n) = 1, processing is performed according to the configuration shown in FIG. 3A, and when M (n)> 1, the processing shown in FIG. The process according to the configuration shown in FIG. FIG. 3B shows an example in the case of M (n) = 2. In FIG. 3, 31-1 to 31-M (n) are signal separation means, 32-1 to 32-M (n) are demodulation means, 33-1 to 33-M (n) are deinterleavers, 34- 1-34-M (n) is a decoding means, 35 is a parallel-serial conversion means (P / S conversion means).

In the case of M (n) = 1, the demodulating means 32 converts the symbol data string by a predetermined modulation method into a bit data string for the other user signal separation signal y _n (k). The deinterleaver 33 restores the bit order by an operation reverse to the interleaving performed on the transmission side. Decryption means 3
4 applies an error correction code to the input bit data string to restore the transmission signal sequence.

When M (n)> 2, the other user signal separation signal y _n (k) is separated into individual transmission sequences by the signal separation means 31. In this case, the received signal is separated from the transmission sequence x _n (k) from the n-th radio terminal apparatus 1- _n by multiplying the channel estimation value B _n shown in (Equation 7) by the inter-user separation weight W _n . This is performed based on the channel estimation value F _n after multiplication of the separation weights between users obtained as a result. The separation algorithm can be realized by applying techniques such as ZF (Zero Forcing), MMSE (Minimum Mean Square Error), and MLD (Maximum likelihood Detection). Here, when using the MLD separation method, this method uses the other user signal separation signal from which the interference signal from the other wireless terminal device is removed for each of the wireless terminal devices 1-1 to 1-Nt. Signal point candidates can be reduced, and real hardware can be realized.

  Note that the separation algorithm may use one method in a fixed manner, or may be adaptively changed according to the number of modulation levels in the transmission sequence, the number of received signals, and the like. For example, MLD is applied when the number of modulation multi-levels such as BPSK and QPSK is small, and in the case of 16QAM and 64QAM with a large number of modulation multi-levels, application of a linear method such as MMSE can be considered.

  Each signal separated for each user includes demodulating means 32-1 to 32-M (n), deinterleavers 33-1 to 33-M (n), and decoding means 34-1 to 34-M (n). ) To output the error-corrected bit string and restore the transmission sequence. Then, the serial data string series is reproduced by the parallel / serial conversion means (P / S conversion means) 35.

  According to the operation as described above, in the present embodiment, when there are a plurality of transmission sequences from the wireless terminal device 1, it is extracted as a signal from which interference of other user signals is removed with one as a unit. As a result, in the subsequent processing, it is possible to apply the reception decoding processing for each user. Therefore, when there are a plurality of transmission sequences, it is necessary to finally convert the parallel data into serial data by the parallel / serial conversion means (P / S conversion means) 35. In this embodiment, however, reception decoding is performed for each user. Since the processing can be performed simultaneously in parallel, the input data to the parallel-serial conversion means 35 is not waited, and no buffer memory for temporarily storing the input data is newly provided, so that the data processing delay is reduced. In addition, an increase in hardware due to an increase in memory can be suppressed.

Also, with regard to reception characteristics, this configuration can obtain better characteristics than the conventional methods (ZF, MMSE) on a realistic hardware scale. That is, instead of the other user signal separation means 5, when the batch separation processing is used by linear processing such as conventional ZF and MMSE, even if there are a plurality of transmission sequences from the wireless terminal device 1, Although it is possible to take out the transmission sequence, STBC (Space Time Block Coding), STTC (Space Time
When a space-time code such as Trellis Coding is applied, and when a plurality of transmission sequences from the same wireless terminal device 1 are included, the degree of freedom of the antenna is reduced for interference suppression due to the property of forming reception weights for separately receiving them. The diversity gain and the space-time coding gain are impaired. On the other hand, in the present embodiment, space-time decoding is possible by using a signal from which interference from other radio terminal apparatus 1 is eliminated, so that diversity gain and space-time coding gain can be obtained. In addition, instead of the other user signal separation means 5, it is possible to introduce a batch separation process based on the conventional MLD, in which case the reception characteristics are better than this embodiment,
When the MLD process is performed on the transmission sequences from all the radio terminal apparatuses 1-1 to Nt, the amount of processing by the MLD increases exponentially with respect to the number of transmission sequences and the number of modulation multilevels. Hardware implementation becomes difficult.

  In this embodiment, the user individual reception processing means 6 is provided for the number Nt of wireless terminal devices to be connected. However, an appropriate index (allowable delay amount of transmission sequence, data type, etc.) based on QoS of the transmission sequence. It is also possible to set the priority for performing the reception processing for each wireless terminal device 1 and sequentially switch the input to the user individual reception processing means 6. As a result, the number of individual user reception processing means 6 can be made smaller than that of the connected wireless terminal device 1 and, depending on the user, the processing delay until the transmission data is restored increases, but the configuration of the wireless base station device 2 is simplified. The effect of becoming is obtained.

(Embodiment 2)
FIG. 4 is a diagram showing a configuration of radio base station apparatus 2a in the uplink according to Embodiment 2 of the present invention. In FIG. 4, a different part from the structure of the radio base station apparatus 2 of FIG. 1 is a structure after the output of the receiving part 4, and below, a different operation | movement part is mainly demonstrated.

  The operations until Nt radio terminal apparatuses 1-1 to 1-Nt each transmit a transmission sequence from an antenna are the same as those in the first embodiment, and a description thereof will be omitted.

In the radio base station apparatus 2a, until the high-frequency signals obtained by a plurality (Nr) of antennas 3 (not shown) are output by the receiving units 4-1 to 4-Nr, the radio in FIG. This is the same as the base station apparatus 2. The receiving units 4-1 to 4-Nr output received signals y (k) expressed by complex digital signals. Here, y (k) is a column vector including as elements the received signals with Nr antennas used for reception. Here, with respect to transmission sequence x _n (k) from radio terminal apparatus 1-n, received signal y at radio base station apparatus 2a at discrete time k obtained in a flat fading propagation environment as in the first embodiment. (K) is expressed as (Equation 1). H _n indicates propagation path variation received by the transmission sequence x _n (k) of the n-th radio terminal apparatus 1-n, and (number of radio base station antennas Nr) rows × (n-th radio terminal apparatus 1 The matrix element h _ij in the i-th row and j-th column is transmitted from the j-th transmission antenna in the n-th radio terminal apparatus 1-n. When the received signal is received by the i-th antenna in the radio base station apparatus 2a, the propagation path variation due to the propagation path is shown. N (k) represents a noise vector having Nr elements added at the time of reception by the Nr antennas of the radio base station apparatus 2a. The transmission sequence x _n (k) is composed of a column vector having M (n) elements.

  Sent by connecting (Nt-1) reception processing means 40-1 to 40- (Nt-1) and one user individual reception processing means 6 sequentially to the output of the receiving unit 4. Decode the data series. FIG. 5 is a diagram showing a detailed configuration of the sth reception processing means 40-s. In FIG. 5, the s-th reception processing means 40-s is composed of other user signal separation means 50-s, user individual reception processing means 6-s, and interference cancellation means 51-s. Decoding is performed for each transmission sequence from the plurality of wireless terminal devices 1 in accordance with a predetermined evaluation criterion for determining the decoding order. Here, s = 1 to (Nt−1). Hereinafter, the operation will be described in order with reference to FIGS.

(1) Processing for s = 1:
The output from the receiving unit 4 is input to the first reception processing unit 40-1 and further input to the other user signal separation unit 50-1. In the other user signal separation means 50-1, the propagation path fluctuation estimated value B _n for the propagation path fluctuation H _n at the discrete time k estimated using a known pilot signal transmitted from the radio terminal apparatus 1- _n is obtained. The inter-user separation weight for separating other user signals from different wireless terminal devices 1 is generated, and the received signal y (k) is multiplied. Here, the operation different from that of Embodiment 1 is that only a transmission sequence from a specific radio terminal apparatus 1-n is separately received from a plurality of radio terminal apparatuses using a predetermined evaluation criterion.

When the transmission sequence preferentially decoded according to a predetermined evaluation criterion is the n-th wireless terminal device 1-n, transmission sequence components other than the transmission sequence x _n (k) of the n-th wireless terminal device 1-n An inter-user separation weight W _n is generated for removing. Where the user isolation weights for the desired n-th radio terminal apparatus 1-n W _n, as shown in equation (2), the propagation path fluctuation estimation excluding the desired n-th radio terminal apparatus 1-n A matrix G (n) composed of values B _j (k) (where j ≠ n) is generated using singular value decomposition. That is, among the left singular vectors u _j constituting the left singular matrix U of the propagation path fluctuation estimated value G (n), the wireless terminal device 1 excluding the desired nth radiant transmits a total of Ms transmission sequences and receives them. When the number of antennas is Nrr, j = (Ms + 1),..., Nr (Nr−Ms) left singular value vectors u _j are selected. As shown in (Equation 3), the selected column vector u _j is used as an inter-user separation weight matrix W _n . Each selected left singular vector u _j becomes a weight for directing a directivity null to the transmission signal excluding the transmission sequence x _n (k) from the desired nth radio terminal apparatus 1-n. In order to generate the separation weight between users, it is necessary to satisfy the condition (number of all transmission sequences from all radio terminal apparatuses) ≦ (number of antennas Nr of radio base stations).

By using the inter-user separation weight W _n generated in this way, the received signal y (k) at the radio base station apparatus 2 is multiplied as shown in (Equation 8), so that another radio terminal apparatus is obtained. The signal y _n (t) in which the interference signal from 1 is reduced can be obtained. Here, n is a natural number equal to or less than Nt. Further, when channel estimation is performed ideally, since the relationship as in (Equation 5) is obtained, (Equation 8) can be transformed as shown in (Equation 9), and y _n (t ) Is a signal from which interference signal components from other wireless terminal apparatuses are completely removed.

Next, the individual user reception processing unit 6-1 determines that the number of transmission sequences of the n-th radio terminal apparatus is M (n) = 1 with respect to the other user signal separation signal y _n (k), or M ( n) Depending on the case of> 2, user individual reception processing is performed by the same operation as in the first embodiment, and the transmitted data series is restored.

The interference cancellation unit 51-s again generates a baseband signal to which encoding processing and modulation similar to those of the transmission sequence are applied, using the restored nth data sequence, and receives the received signal using the channel estimation value. Then, the component of the decoded transmission sequence x _n (k) of the _nth wireless terminal device is removed. FIG. 6 is a diagram showing the configuration of the interference canceling means 51-s. In FIG. 6, 60-s is a signal generation unit that generates a baseband signal that has been subjected to encoding processing and modulation similar to a transmission sequence from a decoded data sequence, and 61-s is a channel estimation unit for the output of the signal generation unit. Channel fluctuation adding means for adding the channel fluctuation received as a received signal using the value, 62-s is a transmission sequence of the nth radio terminal apparatus 1-n decoded from the received signal using the output of the channel fluctuation adding means It is a signal removal means for removing x _n (k). Hereinafter, the operation in FIG. 6 will be described.

The signal generation unit 60-s generates a baseband signal to which encoding processing and modulation similar to the transmission sequence are applied, from the decoded data sequence that is the output of the user individual reception processing unit 6-s. A specific configuration is a reproduction baseband to which modulation processing is added using transmission path encoding means 22, interleaver 23, and modulation means 24 in transmission sequence generation in wireless terminal apparatus 1 used in the description of Embodiment 1. The signal g _n (k) is output. When a plurality of M (n) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n)> 1), g _n (k) is a sequence of M (n) dimensions. It shall consist of a vector.

Next, the channel fluctuation adding means 61-s obtains the propagation path fluctuation estimated value B _n for the propagation path fluctuation H _n at the discrete time k estimated using a known pilot signal transmitted from each wireless terminal device 1 or the like. In addition, the channel fluctuation received as the received signal is added, and the signal removal means 62-s performs a subtraction process from the received signal y (k) to output the _first interference removal signal r ₁ (k). That is, the arithmetic processing shown in (Equation 10) is performed. When the first interference cancellation signal r ₁ (k) obtained here is correctly decoded and channel estimation is ideally performed, the transmission sequence x _{n of the nth} wireless terminal device The signal component from (k) is completely removed.

(2) Processing of Nt>s> 1:
The (s-1) th interference cancellation signal r _s-1 (k) is input to the sth reception processing unit 40-s, and further input to the other user signal separation unit 50-s. In other user signal separating means 50-s, to determine the transmission sequence of decoding preferentially by a predetermined criterion, as in the case of s = 1, the transmission sequence of the n _s -th wireless terminal 1-n _s An inter-user separation weight W _ns for removing transmission sequence components other than x _ns (k) is generated.

By using the propagation path fluctuation estimated value B _n for the propagation path fluctuation H _n at the discrete time k estimated using a known pilot signal transmitted from each wireless terminal apparatus 1 and the like, An inter-user separation weight for separating the user signal is generated, and a multiplication operation is performed on the (s−1) th interference cancellation signal r _s−1 (k). Where the user isolation weight W _ns for a desired second n _s th wireless terminal 1-n _s is (11) as shown in, the desired second n _s th wireless terminal 1-n _s and the It is composed of the propagation path fluctuation estimated value B _j excluding the transmission sequence from the wireless terminal device 1 removed by the first to (s−1) th reception processing means 40-1 to 40- (s−1). For matrix G (n _s ) (where j ≠ n, n ₂ ,... _ns-1 ), generated using singular value decomposition. That is, among the left singular vectors u _j constituting the left singular matrix U of the propagation path fluctuation estimation value G ( _ns ), the desired _ns th wireless terminal device and the first to (s−1) th When transmitting a total of Ms transmission sequences excluding the transmission sequences from the wireless terminal devices removed by the reception processing means 40-1 to 40- (s-1), the number of reception antennas is Nr. j = (Ms + 1),..., Nr (Nr−Ms) left singular vectors u _j are selected. As shown in (Expression 12), the selected left singular vector u _j is used as an inter-user separation weight matrix W _ns .

Using the generated user-to-user separation weight W _ns , the (s−1) -th interference cancellation signal r _s-1 (k) is multiplied as shown in (Equation 13), so that a value other than the desired one is obtained. A signal y _ns (t) in which the amount of interference signal from the wireless terminal device 1 is reduced can be obtained. When channel estimation is ideally performed, a relationship such as (Equation 5) is obtained. Therefore, (Equation 13) can be modified as shown in (Equation 14), and y _ns (t) is The interference signal component from the other wireless terminal device 1 is removed.

Next, the user individual reception processing unit 6-s are to other user signals separated signals y _ns (k), when the transmission sequence number of the n _s -th wireless terminal of M (n _s) = 1, or, Depending on the case of M (n _s )> 2, in the first embodiment, the individual user reception process is performed by the same operation as that described with reference to FIG. 2, and the transmitted data series is restored.

The interference canceling means 51-s again generates a baseband signal with the same encoding process and modulation as the transmission sequence using the restored n _sth data sequence, and receives it using the channel estimation value. A component of the decoded transmission sequence x _ns (k) of the n _sth wireless terminal device is removed from the signal. In FIG. 6, the signal generation unit 60-s generates a baseband signal to which encoding processing and modulation similar to the transmission sequence are applied from the decoded data sequence that is the output of the user individual reception processing unit 6-s. A specific configuration is a reproduction baseband to which modulation processing is added using transmission path encoding means 22, interleaver 23, and modulation means 24 in transmission sequence generation in wireless terminal apparatus 1 used in the description of Embodiment 1. The signal g _ns (k) is output. A plurality of antennas _{(M (n s)> 1} ) by using a plurality M if (n _s) pieces of transmission sequence x _n (k) is transmitted in parallel, g _ns (k) is M (n _s) Suppose that it consists of a dimensional column vector.

Next, the channel fluctuation adding means 61-1 obtains the propagation path fluctuation estimated value B _ns with respect to the propagation path fluctuation H _ns at the discrete time k estimated using a known pilot signal transmitted from each wireless terminal device 1 or the like. Then, channel fluctuation received as a received signal is added, and the signal removal means 62-s performs subtraction processing from the (s−1) th interference removal signal r _s (k) to remove the sth interference. The signal r _s (k) is output. That is, the arithmetic processing shown in (Expression 15) is performed. When the s-th interference cancellation signal r _s (k) obtained here is correctly decoded and ideally channel estimation can be performed, the transmission sequence x of the _ns- th radio terminal apparatus _The signal is removed from the signal component due to _ns (k).

(3) The above operation is repeated until s = (Nt−1). As a result, the (Nt-1) th interference cancellation signal r _s (k) can be extracted by the operation of the (Nt-1) th reception processing means 40- (Nt-1), On the other hand, the received data sequence of the last remaining Nt-th wireless terminal device 1 can be obtained using the individual user reception processing means 6a as in the first embodiment.

  In the sth reception processing means 40-s, there are the following methods as evaluation criteria for determining a transmission sequence to be preferentially decoded. Further, a combination of reception quality and QoS may be used as an evaluation index.

(1) Evaluation criteria based on reception quality:
The received SNR or received SIR for the transmission sequence x _n (k) from the n-th radio terminal apparatus 1-n is set as the evaluation criterion Qn. In such a case, the evaluation criterion based on the received SNR can be set by the evaluation criterion Qn shown in (Equation 16). In this case, decoding is preferentially performed in descending order of Qn. Here, trace (X) is an operator that calculates the eigensum of the matrix X. In the case of SIR evaluation, it is possible to apply a method for evaluating the variance of the pilot signal used for channel estimation with respect to the estimated value.

  Since this embodiment has a successive interference canceller configuration, when a decoding error occurs, it has a characteristic that the adverse effect is propagated to the reception processing means in the subsequent stage, and therefore, a transmission sequence with good reception quality is given priority. Decoding improves characteristics. Therefore, when space-time codes such as STBC and STTC are applied, the reception quality is expected to improve due to the diversity effect, and therefore a method of setting a higher priority may be used.

(2) Evaluation criteria based on QoS:
Based on the QoS of the transmission sequence x _n (k) from the n-th wireless terminal device, an appropriate index (permitted delay amount of transmission sequence, data type, etc.) is provided, and the priority for performing the reception processing is set to the wireless terminal device 1. For each evaluation, the allowable delay amount for the set transmission delay is used as an evaluation criterion.

  Through the operation as described above, in the present embodiment, as in the first embodiment, when there are a plurality of transmission sequences from the wireless terminal device 1, the interference of other user signals is removed using this as one unit. As in the first embodiment, the data transmission delay can be reduced, and the transmission data sequence can be realized without adding a primary storage buffer memory. In addition, when space-time codes such as STBC and STTC are applied, it is possible to obtain better characteristics than the conventional linear processing such as ZF and MMSE. Realization with hardware is possible. Further, the difference from the first embodiment is a sequential interference canceller (SIC) configuration in which the received data sequence is restored for each wireless terminal apparatus 1 and is sequentially removed from the received signal. Although the hardware scale is increased by the configuration as compared with the configuration of the first embodiment, the interference signal components are sequentially removed from the received signal. Since the operation for improving the signal quality can be performed from the interference cancellation, the effect of improving the reception quality can be obtained.

  In this embodiment, a sequential interference canceller configuration is used, but a parallel interference canceller configuration may be used.

  Further, the reception processing means at the subsequent stage may select an interference cancellation signal with good reception quality of the transmission sequence to be decoded without using the interference cancellation signal, and reduce the number of signals. As a result, the hardware scale can be reduced while relatively suppressing performance degradation.

(Embodiment 3)
FIG.7 and FIG.8 is a figure which shows the structure of the radio | wireless terminal apparatus 1c and the radio base station apparatus 2c in the uplink in Embodiment 3 of this invention. In the first embodiment, a transmission method using a single carrier is used. However, in this embodiment, the configuration of the wireless terminal device 1c and the wireless base station device 2c is different because the multicarrier transmission is different. In the following, different operation parts will be mainly described.

Similarly to Embodiment 1, Nt radio terminal apparatuses 1-1 to 1-Nt each transmit a transmission sequence from an antenna. Here, the transmission sequence x _n (k) at the discrete time k transmitted from the nth radio terminal apparatus 1-n to the radio base station apparatus is represented. Here, n is a natural number equal to or less than Nt, and when a plurality of M (n) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n)> 1), a transmission sequence Assume that x _n (k) is composed of an M (n) -dimensional column vector.

7A and 7B is a wireless terminal apparatus that performs multicarrier transmission using OFDM modulation. FIG. 7A shows a case where the wireless terminal device 1c performs transmission using a single antenna, and FIG. 7B shows a case where transmission is performed using a plurality of antennas (in the figure, M (n) = 2 is shown as an example). The configuration is shown. The data sequence generation means 70 generates a data sequence z _n to be transmitted to the radio base station apparatus 2c.

In FIG. 7A, in the case of single antenna transmission, the data sequence z _n generated by the data sequence generation unit 70 is regarded as the transmission sequence x _n (k), and the transmission path encoding unit 72 performs an error at a predetermined coding rate. After performing the correction coding, interleaving is performed by an interleaver 73, and a baseband signal obtained by mapping a bit string to a modulation symbol on an IQ plane using a predetermined multilevel modulation by a primary modulation unit 74, and an OFDM modulation unit 75 is provided. Using this, OFDM modulation including serial / parallel conversion, IFFT conversion, parallel / parallel conversion, and guard interval (GI) insertion is performed. Here, with respect to OFDM modulation and demodulation methods, the literature (Ochi, “OFDM system technology and M
The information is disclosed in the ATLAB simulation explanation “, published by Trikeps), and the description thereof is omitted here. Subsequently, in the transmission unit 76, the baseband signal is frequency-converted and band-limiting processing is performed, and after amplification, the high-frequency signal is obtained. Transmit from antenna 77.

In FIG. 7B, in the case of multi-antenna transmission, the data series z _n generated by the data series generation means 70 by the serial / parallel conversion means 71 (S / P conversion means) is converted into M (n) parallel data strings. Conversion to a certain transmission sequence x _n (k). That is, the transmission sequence x _n (k) is represented as a column vector having M (n) elements. Thereafter, for each transmission sequence, transmission path encoding means 72-1 to 72-M (n), interleavers 73-1 to 73-M (n), primary modulation means 74-1 to 74-M (n), The OFDM modulation means 75-1 to 75 -M (n) and the transmission units 76-1 to 76 -M (n) perform the same processing as the single antenna transmission. It is also possible to transmit using a larger number of antennas than the transmission sequence. In this case, a method of multiplying the transmission sequence by a directivity weight forming a desired directivity, or STBC This can be realized by a method of applying space-time coding. Below, the case where the number of antennas used for transmission in the radio | wireless terminal apparatus 1c and the number of transmission series is the same number is demonstrated.

  Next, the operation in the radio base station apparatus 2c will be described using FIG. In the following, operations after establishing frequency synchronization, phase synchronization, and symbol synchronization will be described. The high-frequency signals received by the Nr multiple antennas 81 are subjected to quadrature detection after amplification and frequency conversion in the receiving units 82-1 to 82-Nr, respectively, converted into baseband signals on the IQ plane, and A / A received signal y (k) expressed as a complex digital signal is output using a D converter. Here, y (k) is a column vector including as elements the received signals with Nr antennas used for reception.

  The OFDM demodulating unit 83-Nr includes a GI removing unit, an FFT unit, and a serial / parallel converting unit (not shown), performs OFDM demodulation, and outputs a symbol data sequence for each of Nc subcarriers. Here, the symbol data series for each fs-th subcarrier at the discrete time k is denoted as Y (k, fs). Y (k, fs) is a column vector including as elements the signals received with Nr antennas used for reception. However, fs = 1 to Nc.

The other user signal separation means 84 has Nc corresponding to the number of subcarriers, and symbol data sequences for different subcarriers from the OFDM demodulation means 83-1 to 83 -Nr having the number of Nr antennas are input to each. . Here, when the fs-th subcarrier data sequence X _n (k, fs) in the transmission sequence from each wireless terminal device 1 is expressed, the relative delay time from the multipath preceding wave in the propagation path is a guard interval. Since the frequency selective fading environment can be handled equivalently to the flat fading propagation environment within the (GI) range, the subcarrier data sequence Y (k, fs) received by the radio base station apparatus 2c is (several 17). Here, H _n (fs) indicates a propagation path variation received by the symbol data sequence X _n (k, fs) of the fs-th subcarrier of the n-th radio terminal apparatus 1-n, and (radio base station It is a matrix composed of (number of antennas Nr) rows × (number of transmission antennas M (n) in the n-th wireless terminal device) column, and the matrix element h _ij of i rows and j columns is the n-th wireless terminal device 1. The signal transmitted from the j-th transmission antenna at −n indicates the propagation path variation due to the propagation path of the fs-th subcarrier signal received by the i-th antenna in the radio base station apparatus 2c. Further, n (k) represents a noise vector having Nr elements added at the time of reception by Nr antennas of the radio base station apparatus.

Hereinafter, the operation of the fs-th other user signal separation unit 84-fs for the fs-th subcarrier data sequence Y (k, fs) will be described. Using propagation path fluctuation estimated value B _n (fs) with respect to propagation path fluctuation H _n (fs) of the fs-th subcarrier group estimated using a known pilot signal transmitted from each wireless terminal device 1c. Then, an inter-user separation weight for separating other user signals from different wireless terminal devices 1c is generated, and a multiplication operation is performed on the fs-th subcarrier data sequence Y (k, fs). Here, the inter-user separation weight W _n (fs) for the fs-th subcarrier data sequence of the desired n-th radio terminal apparatus 1-n is the desired n-th as shown in (Equation 18). A matrix G (n, fs) composed of propagation path fluctuation estimated values B _j (fs) excluding the wireless terminal device 1-n (where j ≠ n) is generated using singular value decomposition. Where ^H is an operator that performs complex conjugate transpose. That is, of the left singular vector u _j constituting the left singular matrix U of the propagation path fluctuation estimated value G (n, fs), the radio terminal device 1 excluding the desired nth singular transmits a total of Ms transmission sequences. When the number of receiving antennas is Nr, j = (Ms + 1),..., Nr (Nr−Ms) left singular vectors u _j are selected. As shown in (Expression 19), the selected left singular vector u _j is used as an inter-user separation weight matrix W _n (fs). Each selected left singular vector u _j is directed to a transmission signal excluding the transmission sequence X _n (k, fs) in the fs-th subcarrier data sequence Y (k, fs) of the desired n-th wireless terminal device. It becomes the weight which turns the sex null. In order to generate the separation weight between users, it is necessary to satisfy the condition of (the number of all transmission sequences from all wireless terminal apparatuses 1c) ≦ (the number of antennas Nr of the number of wireless base stations).

Using the thus generated inter-user separation weight W _n (fs), for the fs-th subcarrier data sequence Y (k, fs) in the radio base station apparatus 2c, as shown in (Expression 20) By multiplying by, it is possible to obtain a subcarrier data sequence Y _n (k, fs) in which interference signal components from other radio terminal apparatuses 1c are reduced. Here, n is a natural number equal to or less than Nt. Further, when channel estimation is ideally performed, a relationship such as (Equation 21) is obtained, and thus (Equation 20) can be transformed as shown in (Equation 22), and Y _n (k , Fs) is a signal from which the interference signal component from the other wireless terminal device 1c is completely removed.

Next, the individual user reception processing means 91-n uses the other user signal separation signal Y _n (k, fs) obtained for each subcarrier (fs = 1 to Nc) of the nth wireless terminal device as one unit. As a result, individual user reception processing is performed. Here, n = 1 to Nt. Some configurations differ depending on whether M (n) is plural or singular.

(A) When there are a plurality of M (n):
The first user individual reception processing means 91-1 in FIG. 8 shows a case where there are a plurality of M (n) (M (n) = 2), 85 is a signal separation means, 86 is a primary demodulation means, 87 is a parallel / serial conversion means (P / S conversion means), 88 is a deinterleaver, 89 is a decoding means, and 90 is a parallel / serial conversion means. When there are a plurality of M (n), the primary demodulation means 86, parallel-serial conversion means (P / S conversion means) 87, deinterleaver 88, and decoding means 89 in the figure each include M (n) systems. .

The signal separation means 85 is provided for each subcarrier (fs = 1 to Nc), and each receives a user signal separation signal Y _n (k, fs). The signal is separated into individual transmission sequences by the signal separation means 85. In this case, the received signal is separated from the fs-th subcarrier data transmission sequence X _n (k, fs) from the n-th wireless terminal device 1c-n by the channel estimation value B _n (Equation 23). This is performed based on the channel estimation value F _n (fs) after multiplication between user separation weights obtained as a result of multiplying fs) by the user separation weight W _n . The separation algorithm can be realized by applying a technique such as ZF, MMSE, or MLD (Maximum likelihood Detection). Here, when the separation method using MLD is used, since this method is a signal from which interference signals from other wireless terminal devices are removed for each wireless terminal device, signal point candidates for MLD can be reduced. Realization with realistic hardware is possible. Note that the separation algorithm may use one method in a fixed manner, or may be adaptively changed according to the number of modulation levels in the transmission sequence, the number of received signals, and the like. For example, MLD is applied when the number of modulation multi-levels such as BPSK and QPSK is small, and in the case of 16QAM and 64QAM with a large number of modulation multi-levels, application of a linear method such as MMSE can be considered.

  Each signal separated for each user is converted into a bit data sequence by the primary demodulation means 86-1 to 86 -M (n) based on mapping information using the symbol data sequence for modulation for each subcarrier. Parallel subcarrier data is converted into a serial beat data string by serial conversion means (P / S conversion means) 87-1 to 87-M (n). The deinterleavers 88-1 to 88-M (n) restore the bit order by the reverse operation to the interleaving performed on the transmission side. Decoding means 89-1 to 89-M (n) apply an error correction code to the input bit data string to restore the transmission signal sequence. Then, the serial data string series is reproduced by the parallel / serial conversion means (P / S conversion means) 90.

(B) When M (n) = 1:
A system of primary demodulation means 86, parallel-serial conversion means (P / S conversion means) 87, deinterleaver 88, and decoding means 89 are connected in series to restore the transmission signal sequence. Each operation is the same as in the case of M (n)> 1, and the description is omitted.

  Through the operation as described above, in the present embodiment, the first embodiment is applied to multicarrier transmission, and a radio base station apparatus in the case where a plurality of radio terminal apparatuses 1c are connected by SDMA using multicarrier transmission. 1c is described. Specifically, when there are a plurality of transmission sequences from the wireless terminal device 1c, each subcarrier is used as a unit as a signal from which interference of other user signals is removed. By performing the extraction, it is possible to apply the reception decoding process for each user individually. Thus, in addition to the effects of the first embodiment, the present embodiment has the following characteristics. That is, since the signal separating unit 85 and the primary demodulating unit 86 for each subcarrier include the transmission signal component of only the wireless terminal device 1c, the processing by the primary demodulating unit 86 can be performed in parallel at the same time, and the parallel / serial converting unit (P / The input data to the S converter 87) and the input data to the parallel / serial converter (P / S converter) 90 are not waited, and a buffer memory for temporarily storing the input data is provided. Therefore, the data processing delay can be reduced, and the increase in hardware scale due to the increase in memory can be suppressed.

Also, with regard to reception characteristics, this configuration can obtain better characteristics than the conventional methods (ZF, MMSE) on a realistic hardware scale. That is, instead of the other user signal separation means 84, when using batch separation processing by linear processing such as conventional ZF and MMSE, even if there are a plurality of transmission sequences from the wireless terminal device 1c as in the embodiment, Although it is possible to extract transmission sequences for each wireless terminal device 1c, when a space-time code such as STBC or STC is applied, when a plurality of transmission sequences from the same wireless terminal device 1c are included, they are separated. Because of the property of forming reception weights for reception, the antenna gain is used to suppress interference, so that diversity gain and space-time coding gain are impaired.

  On the other hand, in this embodiment, space-time decoding is possible by using a signal from which interference from other radio terminal apparatuses is eliminated, so that diversity gain and space-time coding gain can be obtained. In addition, it is possible to apply frequency-space codes such as SFBC (Space Frequency Block Coding) using multi-carrier transmission and different subcarriers and different transmission antennas. In this case as well, conventional ZF, When batch separation processing is used by linear processing such as MMSE, when a plurality of transmission sequences from the same wireless terminal apparatus are included, the degree of freedom of antenna is used for interference suppression due to the property of forming reception weights for separating and receiving them. Therefore, diversity gain and space-time coding gain are impaired. On the other hand, in this embodiment, space-time decoding is possible by using a signal from which interference from other radio terminal apparatuses is eliminated, so that diversity gain and space-time coding gain can be obtained. Further, instead of the other user signal separation means 5, it is possible to introduce a batch separation process based on the conventional MLD. In this case, although all the wireless terminal devices 1 have better reception characteristics than the present embodiment. -When MLD processing is performed on transmission sequences from 1 to Nt, the amount of processing by MLD increases exponentially with respect to the number of transmission sequences and the number of modulation levels, making it difficult to implement realistic hardware. It becomes.

  In this embodiment, the number of wireless terminal devices connected to the individual user reception processing means 91 is provided, but appropriate indicators (allowable delay amount of transmission sequence, data type, etc.) are provided based on the QoS of the transmission sequence. A configuration in which the priority for performing the reception process is set for each wireless terminal device 1c and the input to the individual user reception processing unit 91 is sequentially switched is also possible. In this case, the number of user individual reception processing means 91 can be made smaller than the number of connected wireless terminal devices. In this case, depending on the user, the processing delay until the transmission data is restored increases, but the effect of simplifying the configuration of the radio base station apparatus 2c can be obtained.

(Embodiment 4)
FIG. 9 is a diagram showing a configuration of radio base station apparatus 2d according to Embodiment 4 of the present invention. In the first embodiment, a transmission method using a single carrier is used. However, this embodiment differs in that multicarrier transmission is performed, and the configuration of the radio base station apparatus 2c in FIG. The different part is the configuration after the output of the OFDM demodulating means 83, and the different operation part will be mainly described below.

The operations until Nt radio terminal apparatuses 1-1 to 1-Nt each transmit a transmission sequence from the antenna are the same as those in the third embodiment, and a description thereof will be omitted. Here, the transmission sequence x _n (k) at the discrete time k transmitted from the nth radio terminal apparatus 1-n to the radio base station apparatus 2d is expressed. Here, n is a natural number equal to or less than Nt, and when a plurality of M (n) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n)> 1), a transmission sequence Assume that x _n (k) is composed of an M (n) -dimensional column vector.

  In the radio base station apparatus 2d, a high frequency signal obtained by a plurality (Nr) of antennas 81 (not shown) is output by the receiving units 82-1 to 82-Nr and the OFDM demodulator 83 until the first embodiment. This is the same as the radio base station apparatus 2c of FIG. Here, the output of the OFDM demodulator 83 is a symbol data sequence for each of Nc subcarriers, and the symbol data sequence for each fs-th subcarrier at discrete time k is denoted as Y (k, fs). Y (k, fs) is a column vector including as elements the signals received with Nr antennas used for reception. However, fs = 1 to Nc.

  With respect to the outputs of the OFDM demodulating units 83-1 to 83 -Nr, (Nt−1) reception processing units 95-1 to 95-(Nt−1) and one individual user reception processing unit 91 a are sequentially arranged. By connecting, the transmitted data series is decoded.

  FIG. 10 is a diagram showing a detailed configuration of the sth reception processing means 95-s. In FIG. 10, the s-th reception processing means 95-s includes other user signal separation means 96- (s-1) to 96- (s-Nc), user individual reception processing means 91-s, and interference cancellation means 97. -S, and at the output of each means, decoding is performed for each transmission sequence from the plurality of radio terminal apparatuses 1c according to a predetermined evaluation criterion for determining the decoding order. Here, s = 1 to (Nt−1). Hereinafter, the operation will be described in order with reference to FIGS.

(1) Processing for s = 1:
Output Y (k, fs) from OFDM demodulating means 83-1 to 83 -Nr is input to first receiving processing means 95-1, and among these, fs-th subcarrier group is other It is input to the user signal separation means 96-1-fs. Here, fs is a natural number from 1 to Nc. In other user signal separation means 96-1-1-1 to 96-1-Nc, the fs-th subcarrier group at discrete time k estimated using a known pilot signal transmitted from each wireless terminal device 1 or the like. An inter-user separation weight W _n (fs) for separating other user signals from different wireless terminal devices 1c is generated using the propagation path fluctuation estimated value B _n (fs) for the propagation path fluctuation H _n (fs) of Multiplication is performed on the fs-th subcarrier data series Y (k, fs). Here, the operation different from that of Embodiment 3 is that only a transmission sequence from a specific wireless terminal device 1c is separately received from a plurality of wireless terminal devices 1c using a predetermined evaluation criterion.

When the transmission sequence preferentially decoded according to a predetermined evaluation criterion is the nth radio terminal device 1c-n, the fsth subcarrier data sequence in the transmission sequence from the nth radio terminal device 1c-n An inter-user separation weight W _n (fs) for removing transmission sequence components other than X _n (k, fs) is generated. Here, the inter-user separation weight W _n (fs) for the fs-th subcarrier data sequence of the desired n-th radio terminal apparatus 1c-n is the desired n-th radio terminal apparatus 1c-n, as shown in (Equation 18). Singular value decomposition is used for a matrix G (n, fs) composed of channel fluctuation estimation values B _j (fs) excluding the fs-th subcarrier data sequence of the wireless terminal device (where j ≠ n). To generate. That is, of the left singular vector u _j constituting the left singular matrix U of the propagation path fluctuation estimated value G (n, fs), the wireless terminal device 1c excluding the desired nth radiating unit transmits a total of Ms transmission sequences. When the number of receiving antennas is Nr, j = (Ms + 1),..., Nr (Nr−Ms) left singular vectors u _j are selected. As shown in (Expression 19), the selected left singular vector u _j is used as an inter-user separation weight matrix W _n (fs). Each selected left singular vector u _j is a weight for directing a directivity null to the transmission signal excluding the transmission sequence X _n (k, fs) from the fs-th subcarrier data sequence of the desired n-th wireless terminal device It becomes. In order to generate the separation weight between users, it is necessary to satisfy the condition of (the number of all transmission sequences from all wireless terminal apparatuses 1c) ≦ (the number of antennas Nr of the number of wireless base stations).

By multiplying the fs-th subcarrier data series Y (k, fs) as shown in (Equation 24) using the inter-user separation weight W _n (fs) generated in this way, The signal Y _n (k, fs) in which the interference signal from the wireless terminal device is reduced can be obtained. Here, n is a natural number equal to or less than Nt. Further, when channel estimation is ideally performed, a relationship such as (Equation 21) is obtained. Therefore, (Equation 24) can be transformed as shown in (Equation 25), and Y _n (k , Fs) is a signal from which the interference signal component from the other wireless terminal device 1c is completely removed.

Next, the individual user reception processing unit 91-1 performs the case where the number of transmission sequences of the nth radio terminal apparatus is M (n) = 1 with respect to the other user signal separation signal Y _n (k, fs), or Depending on the case of M (n)> 2, the individual user reception process is performed by the same operation as in the third embodiment, and the transmitted data series is restored.

The interference canceling means 97-1 again generates a subcarrier data sequence subjected to the same encoding process and modulation as the transmission sequence using the restored nth data sequence, and receives it using the channel estimation value. The component by the subcarrier data series _Xn (k, fs) of the decoded nth radio | wireless terminal apparatus 1c-n is removed from a signal. FIG. 11 is a diagram showing the configuration of the interference canceling means 97-s. In FIG. 11, 98-s is a signal generation unit that generates a subcarrier data sequence that has been subjected to encoding processing and modulation similar to a transmission sequence from the decoded data sequence, and 99-s is a subordinate to the output of the signal generation unit. Channel fluctuation adding means for adding channel fluctuation received as a received signal using channel estimation value B _n (fs) for each carrier, 100-S is decoded from the received signal using the output of channel fluctuation adding means 99-S. This is signal removal means for removing a component based on the subcarrier data sequence X _n (k, fs) of the nth radio terminal apparatus. Hereinafter, the operation (s = 1) in FIG. 11 will be described.

The signal generation unit 98-1 generates a subcarrier data sequence obtained by adding the same encoding process and primary modulation as the transmission sequence from the decoded data sequence output from the user individual reception processing unit 91-1. A specific configuration is a subcarrier to which modulation processing is added using transmission path encoding means 72, interleaver 73, and primary modulation means 74 in transmission sequence generation in radio terminal apparatus 1c used in the description of Embodiment 3. The data series g _n (k, fs) is output. When a plurality of M (n) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n)> 1), g _n (k, fs) has M (n) dimensions. It is assumed that it consists of a column vector.

Next, the channel fluctuation adding means 99-1 estimates the propagation path fluctuation with respect to the propagation path fluctuation H _n (fs) at the discrete time k estimated using a known pilot signal transmitted from each wireless terminal device 1c. The channel variation received as the received signal is added using B _n (fs), and the signal removal means 100-1 performs subtraction processing from the fs-th subcarrier data sequence Y (k, fs), The th interference cancellation signal r ₁ (k, fs) is output. That is, the arithmetic processing shown in (Equation 26) is performed. When the first interference cancellation signal r ₁ (k, fs) obtained here is correctly decoded and channel estimation is ideally performed, the subcarrier of the nth radio terminal apparatus is used. This is a signal from which the signal component by the data series X _n (k, fs) has been removed. These operations are performed for all fs = 1 to Nc.

(2) Processing of Nt>s> 1:
The (s−1) th interference cancellation signal r _s-1 (k, fs) is input to the sth reception processing means 95-s, and among these, the fsth subcarrier group is the other user. The signal is input to the signal separation means 96- (1-fs). Here, fs is a natural number from 1 to Nc. In other user signal separating means 96- (s-1) ~96- ( s-Nc), determines the transmission sequence to decode preferentially by a predetermined criterion, as in the case of s = 1, the n _s th wireless terminal 1c-n the fs-th subcarrier data sequence X _ns (k, fs) of _s to generate a user isolation weight W _ns (fs) to remove the transmission sequence components other than.

Propagation path fluctuation estimation value for each radio terminal apparatus 1c-n _s channel of the fs-th subcarrier group in the discrete time k estimated by using a known pilot signal transmitted from the variation H _n (fs) An inter-user separation weight for separating other user signals from different wireless terminal devices 1c is generated using B _n (fs), and the (s−1) -th interference cancellation signal r _s-1 (k, fs) is generated. Is multiplied. Where the user isolation weight W _ns for a desired second n _s th wireless terminal 1c-n _s, as shown in equation (27), first from the desired second n _s th wireless terminal device and the first (S-1) Matrix composed of propagation path fluctuation estimated values B _j (fs) excluding transmission sequences from the wireless terminal device 1c removed by the first reception processing means 95-1 to 95- (s-1). For G (n _s , fs) (where j ≠ n, n 2,..., N _s-1 ), it is generated using singular value decomposition. That propagation path fluctuation estimation value G (n _s, fs) of the left singular vectors u _j constituting a left singular matrix U of the from the desired second n _s th wireless terminal 1c-n _s, and the first A total of Ms transmission sequences excluding the transmission sequence from the wireless terminal device 1c removed by the (s-1) th reception processing means 96-1 to 96- (s-1) are received, and the receiving antenna When the number Nr is set, j = (Ms + 1),..., (Nr−Ms) left singular vectors u _j of Nr are selected. As shown in (Expression 28), the selected left singular vector u _j is used as an inter-user separation weight matrix W _ns (fs).

Using the generated user separation weight W _ns (fs), the (s−1) -th interference cancellation signal r _s-1 (k, fs) is multiplied as shown in (Expression 29). Thus, the fs-th subcarrier data sequence Y (k, fs) in which the amount of interference signals from the wireless terminal device 1c other than the desired one is reduced can be obtained. When channel estimation is ideally performed, a relationship such as (Equation 21) is obtained. Therefore, (Equation 29) can be transformed as shown in (Equation 30), and Y (k, fs) Becomes a signal from which interference signal components from other wireless terminal apparatuses are completely removed.

Next, the user individual reception processing unit 91-s are to other user signals separated signal Y (k, fs), when the transmission sequence number of the n _s -th wireless terminal of M (n _s) = 1, or , M (n _s )> 2, according to the third embodiment, the individual user reception process is performed by the same operation as that described with reference to FIG. 8 to restore the transmitted data series.

The interference cancellation unit 97-s again uses the restored n _sth data sequence to generate a subcarrier signal that has been subjected to the same encoding process and primary modulation as the transmission sequence, and uses the channel estimation value. The component of the decoded transmission sequence X _ns (k, fs) of the n _sth wireless terminal device is removed from the received signal.

FIG. 11 shows a specific configuration. The signal generation unit 98-s adds the same encoding process and primary modulation as the transmission sequence from the decoded data sequence output from the user individual reception processing unit 91-s. Generated subcarrier signals. A specific configuration is a subcarrier to which modulation processing is added using transmission path encoding means 72, interleaver 73, and primary modulation means 74 in transmission sequence generation in radio terminal apparatus 1c used in the description of Embodiment 3. The data series g _ns (k, fs) is output. When a plurality of M (n _s ) M) n _s ) transmission sequences x _n (k) are transmitted in parallel using a plurality of antennas (M (n _s )> 1), g _ns (k, fs ) Is composed of an M (n) -dimensional left singular vector. Then channel fluctuation adding section 99-1, the propagation path for each wireless terminal 1c-n _s channel variation H _ns at discrete time k estimated by using a known pilot signal transmitted from the (fs) The fluctuation estimation value B _ns (fs) is used to add the channel fluctuation received as the received signal, and the signal removal means 100-s responds from the s-1st interference removal signal r _s (k, fs). A subtraction process is performed for each subcarrier signal, and an sth interference cancellation signal r _s (k, fs) is output. That is, the arithmetic processing shown in (Equation 31) is performed. When the s-th interference cancellation signal r _s (k, fs) obtained here is correctly decoded and the channel estimation is ideally performed, the transmission of the _ns- th radio terminal apparatus is performed. The signal from the sequence x _ns (k) is removed. These operations are performed for all fs = 1 to Nc.

(3) The above operation is repeated until s = (Nt−1). As a result, the (Nt-1) -th interference cancellation signal r _s (k, fs) can be extracted by the operation of the (Nt-1) -th reception processing means. The received data sequence of the last remaining Nt-th wireless terminal device 1c can be obtained using the user individual reception processing unit 91a as in the third mode.

  In the reception processing means 95-s, there are the following methods as evaluation criteria for determining a transmission sequence to be preferentially decoded. A combination of both reception quality and QoS may be used as an evaluation index.

(1) Evaluation criteria based on reception quality:
The reception SNR or reception SIR of the average subcarrier signal for the transmission sequence x _n (k) from the n-th wireless terminal device 1c-n is set as the evaluation criterion Qn. In such a case, the evaluation criterion based on the received SNR can be set based on the evaluation criterion Qn shown in (Expression 32). In this case, decoding is performed with priority in the order of Qn. Here, trace (X) is an operator that calculates the eigensum of the matrix X. In the case of SIR evaluation, it is possible to apply a method for evaluating the variance of the pilot signal used for channel estimation with respect to the estimated value.

  In this embodiment, because of the successive interference canceller configuration, when a decoding error occurs, the transmission sequence having good reception quality is given priority to the reception processing means in the subsequent stage, and therefore, the reception quality is good. Decoding improves characteristics. Therefore, when space-time codes such as STBC and STTC are applied, the reception quality is expected to improve due to the transmission diversity effect. Therefore, a method of setting a higher priority may be used.

(2) Evaluation criteria based on QoS:
An appropriate index (allowable delay amount of transmission sequence, data type, etc.) is provided based on QoS of the transmission sequence x _n (k) from the n-th wireless terminal device 1c-n, and the priority for performing the reception processing is wireless. The permissible delay amount for the set transmission delay is used as an evaluation criterion for each terminal device 1c.

  Through the operation as described above, in the present embodiment, in the same way as in the first embodiment, when there are a plurality of transmission sequences from the wireless terminal device 1c, the interference of other user signals is removed using this as one unit. As in the first embodiment, the data processing delay can be reduced and realized without adding a primary storage buffer memory. In addition, when space-time codes such as STBC and STTC are applied, it is possible to obtain better characteristics than the conventional linear processing such as ZF and MMSE. Realization with hardware is possible.

In addition, it is possible to apply frequency-space codes such as SFBC and SFC using multi-carrier transmission using different subcarriers and different transmission antennas. In this case as well, linear processing such as conventional ZF and MMSE is also possible. In the case of using the batch separation process according to the above, when a plurality of transmission sequences from the same wireless terminal device are included, the diversity gain is used because the degree of freedom of antenna is used for interference suppression because of the property of forming reception weights for separating and receiving them. Spoil the spatio-temporal coding gain. On the other hand, in the present embodiment, it is possible to obtain a diversity gain and a space-time coding gain because space-time decoding is possible by using a signal from which interference from another radio terminal apparatus 1c is eliminated.

  Similarly to the third embodiment, this is a sequential interference canceller (SIC) configuration in which the received data sequence is restored for each wireless terminal device 1c and is sequentially removed from the received signal. As a result, the hardware scale increases as compared with the configuration of the first embodiment, but the interference signal components are sequentially removed from the received signal. Since the operation for improving the signal quality can be performed from the interference removal, the effect of improving the reception quality can be obtained.

  In this embodiment, a sequential interference canceller configuration is used, but a parallel interference canceller configuration may be used.

  Further, the reception processing means 95 at the subsequent stage may select an interference cancellation signal with good reception quality of the transmission sequence to be decoded without using any interference cancellation signal, and reduce the number of signals. As a result, the hardware scale can be reduced while relatively suppressing performance degradation.

(Embodiment 5)
12 to 15 are diagrams illustrating different transmission configurations of the wireless terminal device 1 according to the fifth embodiment of the present invention, and FIGS. 16 to 19 correspond to the wireless terminal devices 1 of FIGS. 12 to 15. Then, different configurations of the user individual reception processing means 91 for demodulating and decoding the transmission sequences transmitted from the respective units are shown. The operation when each configuration is used will be described below. In this embodiment, multicarrier transmission is used. However, by assuming that the number of subcarriers is 1, it can be similarly applied to single carrier transmission.

  In the following, a different part from the configuration of radio terminal apparatus 1c at the time of multi-antenna transmission described with reference to FIG. 7B in Embodiment 3 and a user at the time of receiving a plurality of transmission sequences described with reference to FIG. A different part from the structure of the separate reception process means 91 is demonstrated. The other parts perform the same operations as those described in the third or fourth embodiment. Each figure shows a case where the number of Mth transmission sequences M (n) = 2, but is not limited to this.

  In FIG. 12, the configuration of the interleaver 120 is different. Interleaving is performed across the time axis, the space axis (multiple antennas), and the frequency axis (subcarriers) for a plurality of transmission sequences from the transmission path encoding means 72-1 to 72-M (n). FIG. 16 shows a configuration of the user individual reception processing unit 91f corresponding to this, and a plurality of transmission sequences output from the parallel / serial conversion unit (P / S conversion unit) 87 are deinterleaved by the deinterleaver 140. Thus, the transmitted transmission sequence is restored. With this configuration, the randomization effect that lowers the correlation on the time axis, the space axis (multiple antennas), and the frequency axis (subcarrier) and the decoding means 89 that performs error correction are used in combination, which is effective in improving reception quality. It is. Further, in this configuration, the deinterleaver 140 cannot perform processing unless the outputs of the plurality of parallel / serial conversion means (P / S conversion means) 87 are finished in the deinterleaver 140. Since the receiving and decoding processing can be performed simultaneously and in parallel, the output data of the parallel / serial conversion means (P / S conversion means) 87 is not waited more than necessary, and the output data is newly made primary. Since the processing by the deinterleaver 140 can be performed without providing a buffer memory for storing data, the data transmission delay can be reduced and the hardware scale can be reduced. Further, by changing the pattern of the deinterleaver 140 for each terminal device, in the configuration of the SIC shown in the fourth embodiment, a signal for removing the interference and a signal for removing the interference when the interference cancellation unit 97 removes the interference. Even when the correlation between them is high, the reception quality of the decoding result is randomized by different interleavers, so that the effect of improving the final reception characteristics can be obtained.

  FIG. 13 differs in the configuration of the interleaver 121. As a result of interleaving the transmission sequence from the transmission path encoding means 72 across the time axis, the space axis (multiple antennas), and the frequency axis (subcarrier), a plurality of transmission sequences are output. FIG. 17 shows the configuration of the user individual reception processing unit 91g corresponding to this, and the deinterleaver 141 deinterleaves a plurality of transmission sequences output from the serial / parallel conversion unit (S / P conversion unit) 87. Thus, the transmitted transmission sequence is restored. With this configuration, the same effect as the configuration according to FIG. 12 can be obtained. In this case, the circuit configuration is simplified because only one transmission path encoding means 72 and one decoding means 89 are required.

  FIG. 14 differs in the encoding configuration, and uses space-time encoding means 130. The space-time coding means 130 applies STTC, STTTC, etc. disclosed in the document B. Vucetic and J. Yuan, “Space-Time Coding”, Wiley. FIG. 18 shows the configuration of the user individual reception processing unit 91h corresponding to this, and the space-time decoding unit 150 which decodes the space-time encoding applied to the transmission sequence deinterleaved by the deinterleaver 88. The transmission sequence transmitted by is restored. With this configuration, although the transmission rate is reduced, a space-time diversity effect can be obtained, which contributes to improvement in reception quality. Also, with this configuration, it is possible to obtain better characteristics than the conventional methods (ZF, MMSE) with a realistic hardware scale. That is, instead of other user signal separation means, when using batch separation processing by conventional linear processing such as ZF and MMSE, even if there are a plurality of transmission sequences from the wireless terminal device 1 as in the embodiment, Although it is possible to extract the transmission sequence for each wireless terminal device 1, when a space-time code is applied, when a plurality of transmission sequences from the same wireless terminal device are included, a reception weight for separating and receiving them is formed. Therefore, since the degree of freedom of the antenna is used to suppress interference, the diversity gain and the space-time coding gain are impaired. On the other hand, in this embodiment, space-time decoding is possible by using a signal from which interference from other radio terminal apparatuses is eliminated, so that diversity gain and space-time coding gain can be obtained.

  FIG. 15 differs in the encoding configuration, and uses space-time encoding means 131. The space-time coding means 131 applies block coding such as STBC disclosed in the document B. Vucetic and J. Yuan, “Space-Time Coding”, Wiley. FIG. 19 shows the configuration of the user individual reception processing means 91i corresponding to this, and the space-time decoding means 160 performs a decoding process on the applied space-time coding. With this configuration, although the transmission rate is reduced, a space-time diversity effect can be obtained, which contributes to improvement in reception quality. Also, with this configuration, it is possible to obtain better characteristics than the conventional methods (ZF, MMSE) with a realistic hardware scale. That is, instead of other user signal separation means, when using batch separation processing by conventional linear processing such as ZF and MMSE, even if there are a plurality of transmission sequences from the wireless terminal device 1 as in the embodiment, Although it is possible to extract the transmission sequence for each wireless terminal device 1, when a space-time code is applied, when a plurality of transmission sequences from the same wireless terminal device 1 are included, a reception weight for separately receiving them is set. Because of the nature of the antenna, the degree of freedom of the antenna is used to suppress interference, so that the diversity gain and the space-time coding gain are impaired. On the other hand, in the present embodiment, space-time decoding is possible by using a signal from which interference from other radio terminal apparatus 1 is eliminated, so that diversity gain and space-time coding gain can be obtained. The space-time coding means 131 may perform (time axis) space-time coding on continuous symbol data, but the same applies when frequency-space coding is performed between adjacent subcarriers. An effect is obtained.

  Note that the configuration of each wireless terminal device 1 and the corresponding user individual reception processing means 91 shown in the present embodiment may be combined with each other.

(Embodiment 6)
FIG. 20 is a diagram showing different transmission configurations of radio terminal apparatus 1 according to Embodiment 6 of the present invention, in order to demodulate and decode the transmission sequences transmitted from each corresponding to the configuration of radio terminal apparatus 1. The different structure of the individual user reception processing means 91 is shown. The operation will be described below. In this embodiment, multicarrier transmission is used. However, by assuming that the number of subcarriers is 1, it can be similarly applied to single carrier transmission.

  In the following, a different part from the configuration of radio terminal apparatus 1c at the time of multi-antenna transmission described with reference to FIG. 7B in Embodiment 3 and a user at the time of receiving a plurality of transmission sequences described with reference to FIG. A different part from the structure of the separate reception process means 91 is demonstrated. The other parts perform the same operations as those described in the third or fourth embodiment. Each figure shows a case where the number of Mth transmission sequences M (n) = 2, but is not limited to this.

  FIG. 20 shows a spatio-temporal phase rotation unit 190 that applies a phase rotation that varies in advance in time and space to the modulation symbol data series output from the primary modulation units 74-1 to 74-M (n). A signal is input to the OFDM modulation means 75 after being spatio-temporal phase rotated by the spatio-temporal phase rotation means 190.

  FIG. 21 shows the configuration of the user individual reception processing unit 91j corresponding to this, and the spatio-temporal phase for outputting information on the spatio-temporal phase rotation added by the spatio-temporal phase rotation unit 190 at the time of transmission of the wireless terminal device 1 The rotation information output unit 191 is different from the rotation information output unit 191 in that a signal separation unit 192 that performs signal separation using the rotation information output unit 191 is included. In principle, the signal separation means 192 performs signal separation using MLD. However, in this case, since the modulation mapping given by the primary modulation means 74 is changed by the spatio-temporal phase rotation means 190, the phase rotation by the spatio-temporal phase rotation information output means 191 is given to the candidate points by the predetermined modulation mapping. A symbol having a minimum signal point distance to the candidate point is output as a transmission symbol sequence.

  When a plurality of transmission sequences are transmitted from the wireless terminal device 1j, if the correlation between these signals is high, the separation characteristics are degraded by the linear separation method such as MMSE or ZF. There is MLD as a non-linear separation method, but burst errors are likely to occur when signal points of a plurality of transmission sequences overlap due to propagation path fluctuations. Therefore, as shown in this configuration, a known phase rotation is given in advance between transmission and reception for symbol points at the time of transmission, and an effect of reducing burst errors can be obtained by using an interleaver and an error correction code in combination. Further, in this configuration, since the other user signal separation unit 84 is used, since it can be performed after removal from the transmission sequence from the other wireless terminal device 1, a significant effect of reducing signal point candidates and reducing the operation scale. Is obtained.

  The radio base station apparatus and radio communication method according to the present invention are useful for spatial multiplexing transmission and are suitable for radio communication using spatial division multiple access and spatial multiplexing.

The block diagram which shows the structure of the wireless base station apparatus in Embodiment 1 of this invention. (A), (b) Block diagram which shows the structure of the radio | wireless terminal apparatus in Embodiment 1 of this invention. (A), (b) The block diagram which shows the structure of the user separate reception process means in Embodiment 1 of this invention. The block diagram which shows the structure of the wireless base station apparatus in Embodiment 2 of this invention. The block diagram which shows the structure of the reception process means in Embodiment 2 of this invention. The block diagram which shows the structure of the interference cancellation means in Embodiment 2 of this invention. (A), (b) The block diagram which shows the structure of the radio | wireless terminal apparatus in Embodiment 3 of this invention. The block diagram which shows the structure of the wireless base station apparatus in Embodiment 3 of this invention. Block diagram showing a configuration of a radio base station apparatus according to Embodiment 4 of the present invention The block diagram which shows the structure of the reception process means in Embodiment 4 of this invention. The block diagram which shows the structure of the interference cancellation means in Embodiment 4 of this invention. FIG. 9 is a block diagram showing a configuration of a wireless terminal device in the fifth embodiment of the present invention. FIG. 9 is a block diagram showing a configuration of another wireless terminal device according to Embodiment 5 of the present invention. FIG. 9 is a block diagram showing a configuration of another wireless terminal device according to Embodiment 5 of the present invention. FIG. 9 is a block diagram showing a configuration of another wireless terminal device according to Embodiment 5 of the present invention. The block diagram which shows the structure of the user separate reception process means in Embodiment 5 of this invention. Block diagram showing the configuration of another individual user reception processing means in Embodiment 5 of the present invention Block diagram showing the configuration of another individual user reception processing means in Embodiment 5 of the present invention Block diagram showing the configuration of another individual user reception processing means in Embodiment 5 of the present invention FIG. 9 is a block diagram showing a configuration of a wireless terminal device in a sixth embodiment of the present invention. The block diagram which shows the structure of the user separate reception process means in Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless terminal device 2 Wireless base station apparatus 3, 77, 81 Antenna 4, 82 Receiver 5, 50, 84, 96 Other user signal separation means 6, 91 User individual reception processing means 20, 70 Data sequence generation means 21, 71 Series-parallel conversion means (S / P conversion means)
35, 87, 90 Parallel / serial conversion means (P / S conversion means)
22, 72 Transmission path coding means 23, 73, 120, 121 Interleaver 24 Modulation means 25, 76 Transmitter 31, 85, 192 Signal separation means 32 Demodulation means 33, 88, 140, 141 Deinterleaver 34, 89 Decoding Conversion means 40, 95 reception processing means 51, 97 interference cancellation means 60, 98 signal generation means 61, 99 channel variation addition means 62, 100 signal removal means 74 primary modulation means 75 OFDM modulation means 83 OFDM demodulation means 86 primary demodulation means 130 131 Space-time encoding means 150, 160 Space-time decoding means 190 Space-time phase rotation means 191 Space-time phase rotation information output means

Claims (14)

In a radio base station apparatus that separately receives a plurality of signal sequences spatially multiplexed from a plurality of radio terminal apparatuses using a plurality of antennas,
At least one of the plurality of wireless terminal devices includes a spatial multiplexing transmission wireless terminal device that transmits a plurality of signal sequences,
And other user signal removal means for extracting the plurality of spatial multiplexing transmission reception signal sequence to remove the component of the received signal or found other users signal sequence from the spatial multiplexing transmission radio terminal device by the antenna as a unit,
A radio base station apparatus comprising user individual reception processing means for performing reception processing for each user based on the output of the other user signal removal means. The other user signals removal means channel the spatial multiplexing transmission wirelessly components are removed by Ri other user signals sequence in the user separation weights generated using a singular value decomposition with respect composed matrix from fluctuation estimation value The radio base station apparatus according to claim 1, wherein a reception signal sequence of the terminal apparatus is extracted as one unit . In a radio base station apparatus that separately receives a plurality of signal sequences spatially multiplexed from a plurality of radio terminal apparatuses using a plurality of antennas,
At least one of the plurality of wireless terminal devices includes a spatial multiplexing transmission wireless terminal device that transmits a plurality of signal sequences,
Priority determining means for determining a priority for decoding a transmission signal from a wireless terminal device using a predetermined selection criterion;
And other user signal removal means for extracting a received signal sequence of the spatial multiplexing transmission wireless terminal device based on the output of said priority determining means as a unit,
Based on the output of the other user signal removal means, user individual reception processing means for decoding the transmission signal from the spatial multiplexing transmission radio terminal device;
Selective signal separation means for regenerating a signal received by the spatial multiplexing transmission radio terminal apparatus and removing it from the signals received by the plurality of antennas from the output of the user individual reception processing means and the channel estimation result;
Sequentially said priority radio base station apparatus for decoding a transmission signal from the wireless terminal device in the order of.   The radio base station apparatus according to claim 3, wherein the priority determination means preferentially decodes in order from the smallest allowable delay amount in a transmission sequence from the plurality of radio terminal apparatuses.   The radio base station apparatus according to claim 3, wherein the priority determination means preferentially decodes in descending order of reception quality of transmission sequences from the plurality of radio terminal apparatuses. When the space-multiplex transmission radio terminal apparatus transmits a signal sequence subjected to space-time coding, the user individual reception processing means performs the plurality of transmissions on the space-multiplex transmission radio terminal apparatus that performs space- time coding and transmission. The radio base station apparatus according to claim 1, wherein the radio base station apparatus receives the signal sequence after space-time decoding. When the radio terminal device performs radio transmission using a multicarrier, and the spatial multiplexing transmission radio terminal device transmits a signal sequence subjected to frequency-space coding,
The radio base station apparatus according to claim 1 or 3, wherein the user individual reception processing means performs frequency-space decoding and reception. The radio base station apparatus according to claim 1 or 3, wherein a signal sequence subjected to space-time interleaving using different interleave patterns is transmitted to the plurality of radio terminal apparatuses. The radio terminal apparatus performs radio transmission using multicarriers, and the spatial multiplexing transmission radio terminal apparatus performs a frequency-space interleaver that uses different interleave patterns between the plurality of radio terminal apparatuses. The radio base station apparatus according to claim 1 or 3, wherein When the spatial multiplexing transmission radio terminal device transmits a signal sequence given a known spatio-temporal phase rotation in advance, the user individual reception processing means performs the spatio-temporal phase rotation and transmits the spatial multiplexing transmission radio terminal device On the other hand, the radio base station apparatus according to claim 1 or 3, wherein the plurality of signal sequences are received by performing space-time decoding using information on the space-time phase rotation. The radio base station apparatus according to claim 6, wherein the selective signal separation means preferentially decodes a signal series subjected to space-time coding among transmission sequences from the plurality of radio terminal apparatuses. The radio base station apparatus according to claim 7, wherein the selective signal separation means preferentially decodes a signal series subjected to frequency-space coding among transmission sequences from the plurality of radio terminal apparatuses. A plurality of wireless terminal devices a plurality of signal sequences that are spatially multiplexed transmission from the wireless communication method of the radio base station apparatus for separating reception using a plurality of antennas,
At least one of the plurality of wireless terminal devices includes a spatial multiplexing transmission wireless terminal device that transmits a plurality of signal sequences,
Extracting the received signal sequence to remove the component of the received signal or found other users signal series by the plurality of antennas the spatial multiplexing transmission wireless terminal device as a unit,
And a user-specific reception process for performing a reception process for each user based on the output of the other-user signal removal means. In a radio communication method of a radio base station apparatus for separately receiving a plurality of signal sequences spatially multiplexed from a plurality of radio terminal apparatuses using a plurality of antennas,
At least one of the plurality of wireless terminal devices includes a wireless terminal device that transmits a plurality of signal sequences,
Determining a priority for decoding a transmission signal from the wireless terminal device using a predetermined selection criterion;
A step of other user signals is removed to extract a received signal sequence of the spatial multiplexing transmission wireless terminal device based on the priority determined result as a unit,
Based on the output of the other user signal removal step, a step of performing user individual reception processing for decoding a transmission signal from the spatial multiplexing wireless terminal device;
From the output and the channel estimation result of the user-specific reception processing step, and reproduces the received signal by the spatial multiplexing transmission wireless terminal device and an interference canceling step of removing from the signal received by the plurality of antennas,
Wireless communication method for decoding a transmission signal from the wireless terminal device in the order of sequentially the priority of the above operation.

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