WO2007071106A1

WO2007071106A1 - Transmitter, receiver and corresponding method

Info

Publication number: WO2007071106A1
Application number: PCT/CN2005/002250
Authority: WO
Inventors: Liang Sun; Junfeng Zhang
Original assignee: Zte Corporation
Priority date: 2005-12-20
Filing date: 2005-12-20
Publication date: 2007-06-28
Also published as: CN101258704B; CN101258704A

Abstract

A transmitter and receiver in a multi-user multiple input/multiple output communication system and corresponding transmission method and reception method in which: upon transmitting, an user information bit stream is mapped to be a symbol sequence via a symbol mapper mapped symbol sequence is divided into multi-channel data by a demultiplexer the symbol sequence of each path is appended a cyclic prefix via a cyclic prefix generator the symbol sequence which is appended a cyclic prefix passes through a multiplier and said symbol sequence is multiplied by a chip generated in spread spectrum code generator, and obtains a data frame. Upon receiving all kinds of interferences caused by frequency selective fading are confronted by using single carrier frequency domain equalizer the influence of error propagation due to serial interference elimination is reduced by using iterative layered space-frequency detection algorithm. Present invention restrains effectively ISI and ICI between multi-user signals thus improves average performance of the system, and increases greatly system capacity.

Description

Transmitter, receiver and method therefor

Technical field

The present invention relates to a mobile communication system, and more particularly to a transmitter, a receiver, a transmitting method, and a receiving method for an uplink multi-user multiple input multiple output (MIMO) asynchronous communication system in the field of mobile communications. Background technique

Future mobile communication systems require data transmission rates of up to 100 Mbit/ _s , and supported services will be extended from voice services to multimedia services (including real-time streaming services). The ability to implement high-rate and large-capacity technologies on limited spectrum resources has become a hot topic of current research. Compared with the single antenna system, the MIMO system utilizes the antenna array of the base station and the terminal to achieve multiple transmission and multiple reception, thereby making full use of multiple parallel spatial subchannels in the scatterer-rich wireless channel, thereby eliminating the need to increase spectrum resources. In the case of antenna transmit power, system capacity and diversity gain are doubled, and thus have received widespread attention in recent years.

Broadband mobile communication systems typically experience the frequency selectivity of the channel. The frequency selectivity of a channel is that the channel has different attenuation at different frequencies. Frequency selective channels typically cause severe intersymbol interference (ISI) and multiple access interference (MAI). This has a large impact on MIMO systems that require operation at high SNR conditions. The most common method for countering frequency selective fading is to use single carrier equalization technology at the receiving end, which is divided into two categories: single carrier time domain equalization technology and single carrier frequency domain equalization technology. Single-carrier time domain equalization technology is a mature technology with strong anti-interference ability. However, the complexity of the single-carrier time-domain equalizer and the maximum delay of the channel are spread in a cubic relationship, so single-carrier time-domain equalizers are difficult to implement in some practical applications (such as wideband MIMO systems). Another equalization technique, single-carrier frequency domain equalization, overcomes the shortcomings of single-carrier time domain equalization. In a frequency selective fading channel, the received signal is a convolution of the transmitted signal and the channel impulse response in the time domain, and is transmitted in the frequency domain. The product of the transmitted signal and the channel's frequency domain response. According to the channel frequency domain response obtained by the channel estimation, the single carrier frequency domain equalizer can be separately equalized at each frequency point, so that the computational complexity is greatly reduced. In theory, the performance of a single carrier frequency domain equalizer is the same as that of a single carrier time domain equalizer, and its complexity is comparable to that of an orthogonal frequency division multiplexing system.

Previous studies of MIMO systems have focused on single-user point-to-point multi-antenna communication systems, regardless of co-channel interference between multiple users. At present, researchers at home and abroad have begun to shift their focus to multi-user MIMO systems. Multi-user MIMO systems have large differences compared to single-user MIMO systems. Co-channel interference (ICI) is not considered in single-user systems. In multi-user systems, if the co-channel interference is not well handled, It can cause serious deterioration of system performance. On the downlink, the signals of all users transmitted at the same time arrive at the mobile station synchronously, and in the uplink, the user signals arrive at the base station asynchronously, so the impact of ICI on the system is more prominent than in the downlink uplink. Summary of the invention

The technical problem to be solved by the present invention is to provide a transmitter, a receiver, a transmitting method and a receiving method for a multi-user multiple input multiple output (MIMO) communication system in the field of mobile communications, in order to combat multi-user co-channel interference and frequency. Selective fading, suppressing ISI and ICI between multi-user signals.

In order to solve the above technical problem, the present invention provides a signal transmission method for a multi-user mobile communication system, which includes the following steps:

Mapping a user information bitstream into a sequence of symbols;

Decomposing the mapped symbol sequence into a multiplex symbol sequence;

Adding a cyclic prefix to each of the decomposed symbol sequences;

Allocate system code resources to users (groups);

Generating a spreading code chip according to the allocated system code resource;

The symbol sequences added to the cyclic prefix are respectively multiplied by the chips to obtain a data frame and then transmitted. Wherein, the step of adding a cyclic prefix may be replaced by a zero-adding technique, which adds zero before or after the transmitted data block.

In the step of allocating system code resources, when the total number of antennas of several users in the system is not greater than the number of receiving antennas, these users may be grouped into one group, and each group is assigned the same spreading code. The present invention also provides a transmitter for a multi-user mobile communication system, comprising: a user information bit stream generator for generating a user information bit stream;

a symbol mapper for mapping the user information bit stream into a symbol sequence; a demultiplexer for decomposing the mapped symbol sequence into a multi-way symbol sequence; a cyclic prefix generator for decomposing A cyclic prefix is added to each symbol sequence; a system code resource allocator is used to allocate system code resources to users (groups);

a spreading code generator, configured to generate a spreading code chip according to the allocated system code resource; a multiplier, configured to multiply the symbol sequence of each path added to the cyclic prefix by the chip to obtain a data frame . The present invention also provides a signal receiving method for a multi-user mobile communication system, comprising the following steps:

(1) corresponding to each receiving antenna, respectively canceling the cyclic prefix in the time domain signal data received by each receiving antenna, respectively performing data recombination on the signal after eliminating the cyclic prefix, and separately recombining the signal in the time domain Despreading, separating the received signal of a particular user (group) from the received signals of other users (groups);

(2) performing a Fourier transform on the separated time domain received signal of the user (group), converting it into a frequency domain received signal of the user (group), and performing frequency domain receiving signals of the user (group) after the conversion. Data reorganization;

(3) estimating an impulse response of each channel, and performing Fourier transform on the estimated signal impulse responses to be converted into a frequency domain response; (4) Calculating the equalization coefficients of the frequency domain equalizers of all currently undetected transmit antennas at each frequency point according to the frequency domain received signals of the reassembled user (group) and the frequency domain response of each channel ;

(5) calculating an average signal-to-noise-to-interference ratio on all currently undetected transmit antennas, determining a currently-transmitted transmit antenna based on the order of the signal-to-noise-interference ratio, and determining the current current set according to the obtained equalization coefficient Detecting a transmit antenna for equalization, and obtaining an estimated frequency domain signal of the transmit antenna;

(6) performing inverse Fourier transform on the frequency domain signal estimation value of the currently detected transmit antenna, and determining a decision value of the corresponding transmit antenna transmit data according to the transformed signal;

(7) taking the decision data as an output, and after one-way Fourier transform, transforming into a frequency domain signal, and multiplying the transformed frequency domain signal by a channel frequency domain response vector corresponding to the currently detected transmitting antenna, Reconstructing the interference signal of the transmitting antenna;

(8) canceling the reconstructed interference signal and the reassembled frequency domain received signal of the user (group) to obtain a new frequency domain receiving signal of the user (group);

(9) Zeroing the channel response vectors of the current detection antennas in the frequency domain response matrix of each channel to obtain a new frequency domain response of each channel;

(10) re-executing the steps (4)-(10) according to the new frequency domain received signal of the user (group) and the new frequency domain response of each channel, and sequentially iterating through the signals between the antennas until All transmitting antennas are detected;

(11) The decision value corresponding to the transmission data of all the transmitting antennas is parallel-converted to obtain the transmission data of the user (group).

In the step (5), the undetected transmitting antenna with the largest signal-to-noise interference ratio may be determined as the transmitting antenna currently to be detected.

The step (11) may include:

(11A) performing data recombination on the decision value corresponding to the transmission data of all transmitting antennas;

(11B) performing the parallel conversion of the data recombined data to obtain the transmission data of the user. The present invention also provides a receiver for a multi-user mobile communication system, comprising: a cyclic prefix canceller, configured to cancel a cyclic prefix in time domain signal data received by a corresponding receiving antenna;

a first data recombiner, configured to reassemble the signal data after canceling the cyclic prefix; and a despreader for despreading the reassembled signal in a time domain to receive a specific user (group) Separating from other user (group) signals to obtain the time domain receiving signal of the user (group);

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to convert the separated time domain received signal of the user (group) and each channel impulse response estimated by the channel estimator into frequency domain reception of the user (group) Signal and frequency domain response of each channel;

a second data recombiner, configured to recombine frequency domain received signal data received by each receiving antenna of the user (group) and transformed by a corresponding first Fourier transform unit; a frequency domain equalizer coefficient calculating unit And calculating, according to the user (group) frequency domain receiving signal and the frequency domain response of each channel, calculating an equalization coefficient of each frequency domain equalizer at each frequency point;

a sorting and frequency domain equalization unit, configured to calculate an average signal-to-noise interference ratio on all currently undetected transmit antennas, determine a currently-transmitted transmit antenna according to a sort of the signal-to-noise-interference ratio, and obtain a balance coefficient according to the obtained The currently detected transmit antenna is equalized to obtain an estimated frequency domain signal of the transmit antenna;

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; a determiner, configured to determine the signal after the inverse Fourier transform, to obtain a judgment that the user (group) transmits data corresponding to the transmit antenna Value

a second Fourier transform unit, configured to transform the decision data output by the decider into a frequency domain signal;

a signal recovery unit, configured to convert the frequency domain signal transformed by the second Fourier transform unit The channel frequency domain response vector corresponding to the transmitting antenna is multiplied, and the interference signal of the transmitting antenna is reconstructed in the frequency domain;

An interference canceller, configured to cancel the reconstructed interference signal and the reassembled frequency domain received signal of the user (group) to obtain a new frequency domain receiving signal of the user (group), The channel response vector corresponding to the current detecting antenna in each frequency domain response matrix is set to zero, and a new frequency domain response of each channel is obtained, and the user (group) new frequency domain receiving signal and the new channel frequency are obtained. The domain response returns the frequency domain equalizer coefficient calculation unit;

The parallel-serial converter is configured to perform parallel-to-serial conversion of the decision values corresponding to the transmission data of all the transmitting antennas to obtain the transmission data of the user (group). The invention may further comprise:

The third data recombiner is configured to perform data recombination before the decision value corresponding to the transmission data of all the transmitting antennas, and then enter the parallel-to-serial converter. The present invention also provides a signal receiving method for a multi-user mobile communication system, comprising the following steps:

(3) estimating the impulse response of each channel, and performing Fourier transform on the estimated signal impulse responses to be converted into a frequency domain response;

(4) Calculating the frequency domain equalizers of all currently undetected transmit antennas at each frequency according to the frequency domain received signals of the reassembled user (group) and the frequency domain response of each channel The equalization coefficient at the point; -

(5) calculating an average signal-to-noise-to-interference ratio on all currently undetected transmit antennas, determining a currently-transmitted transmit antenna according to the order of the signal-to-noise-interference ratio, and correcting the determined current one according to the obtained equalization coefficient Detecting a transmit antenna for equalization, and obtaining an estimated frequency domain signal of the transmit antenna;

(6) performing inverse Fourier transform on the frequency domain signal estimation value of the currently detected transmitting antenna, and determining a decision value of the corresponding transmitting antenna transmission data according to the transformed signal;

(8) canceling the reconstructed interference signal and the recombined frequency domain received signal of the user (group) to obtain a new frequency domain receiving signal of the user (group);

(10) re-executing the steps (4)-(10) according to the new frequency domain received signal of the user (group) and the new frequency domain response of each channel, and sequentially iterating through the signals between the antennas until After all the transmitting antennas are detected, the detection order of all the transmitting antennas is ^, C', and the detection order of the transmitting antennas is recorded, and the equalizer coefficients of the corresponding transmitting antennas corresponding to the order are recorded;

(11) Using the transmitted data sequence of the last detected transmit antenna as the known interference of the transmit data stream of the other transmit antennas, performing serial interference cancellation on each layer in the order of -, and using the equalizer coefficients obtained last time. To reconstruct the interference signal, obtain a new sequence of detection symbols of all the transmitting antennas, and record the equalizer coefficients corresponding to the detection order of the transmitting antennas in the process;

(12) If the obtained new data sequence ⁶ ^ of the last detected transmitting antenna is the same as the result of the previous detection, or the number of measured iterations reaches the requirement, the iteration is terminated, and the final detection result is obtained; (13) The detection result of all the antennas is passed through the parallel-serial converter to obtain the transmission data of the user (group). Wherein, in the step (12), if the detection results are not the same, and the number of iterations does not meet the requirement, then ^{6 is} used as a new known interference, and the previously obtained equalizer coefficients are used to reconstruct the interference signal, according to >d _〉'''^ sequence, re-test each layer. The step (13) may include:

(13A) performing data recombination on the decision value corresponding to the transmission data of all the transmitting antennas; (13B) performing parallel-to-serial conversion on the data recombined data to obtain the transmission data of the user. The present invention also provides a receiver for a multi-user mobile communication system, comprising: a cyclic prefix canceller for canceling a cyclic prefix in time domain signal data received by a corresponding receiving antenna;

a first data recombiner, configured to reassemble the signal data after canceling the cyclic prefix; and a despreader for despreading the reassembled signal in a time domain to receive a specific user (group) Separating from other user signals (groups) to obtain a time domain received signal of the user (group);

a channel estimator for estimating an impulse response of each channel;

a second data recombiner, configured to recombine frequency domain received signal data received by each receiving antenna of the user (group) and transformed by a corresponding first Fourier transform unit; a frequency domain equalizer coefficient calculating unit And calculating, according to the user (group) frequency domain receiving signal and the frequency domain response of each channel, calculating frequency domain equalizers of all transmitting antennas at respective frequency points. Equalization coefficient

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; a determiner, configured to determine, by the inverse Fu 5: leaf transformed signal, to obtain a corresponding transmit antenna of the user (group) The decision value of the data;

a first memory, configured to store a decision value output by the decider;

a signal recovery unit, configured to multiply the frequency domain signal transformed by the second Fourier transform unit by a channel frequency domain response vector corresponding to the transmit antenna, and reconstruct an interference signal of the transmit antenna in a frequency domain;

An optimal detection sequence memory for storing sequential iterations of signals passing between antennas until all transmission antennas are detected, and the resulting antenna detection sequence is obtained.

;

An equalizer coefficient memory for storing an equalization coefficient of the corresponding transmitting antenna calculated in the sequential iterative process;

The forward serial interference canceller is configured to use the transmitted data sequence of the last detected transmit antenna as the known interference of the transmit data stream of other transmit antennas, and perform serial interference cancellation on each layer in the order of ...-, ' Obtaining a new sequence of detected symbols for all transmit antennas; a comparator for the new data sequence of the resulting last detected transmit antenna Comparing with the result of the last detection stored in the first memory, if the comparison is the same, stopping the iteration;

An iteration count counter for recording the number of iterations, and when the number of iterations measured reaches the requirement, the iteration is stopped;

a second memory, configured to record a final measurement result when the iteration is stopped; and a parallel-serial converter for performing parallel-to-serial conversion on the final measurement result to obtain transmission data of the user (group). The invention may further comprise:

Reverse serial interference canceler, for a detection result is not the same in the new data sequence stored in this last transmitting antenna is detected in the first memory, and not the number of iterations is reached, ⁶ ^ As a new known interference, re-test each layer according to the order of ^―〉^―〉...-^. The invention may further comprise:

And a third data recombiner, configured to perform data recombination before the final measurement result is parallel-converted, and then enter the parallel-to-serial converter. With the transmitter of the present invention and its method, the performance of a multi-user multiple input multiple output (MIMO) system can be improved, and the complexity of the system equipment can be further reduced by using the receiver and method of the present invention. The present invention effectively suppresses ISI and ICI between multi-user signals, thereby improving the average performance of the system and greatly increasing the capacity of the system. BRIEF abstract

1 is a schematic diagram of an uplink multi-user MIMO-CDMA asynchronous communication system;

2 is a CDMA spread spectrum mode and a frame structure adopted by a sender according to an embodiment of the present invention; 3 is a schematic structural diagram of a transmitter according to an embodiment of the present invention;

4 is a schematic structural diagram of a receiver according to Embodiment 1 of the present invention;

FIG. 5 is a schematic structural diagram of a receiver according to Embodiment 2 of the present invention; FIG.

6 is a schematic structural diagram of a receiver according to Embodiment 3 of the present invention;

Figure 7 is a block diagram showing the structure of a receiver according to Embodiment 4 of the present invention.

Referring to Figure 1, the structure of an uplink multi-user Code Division Multiple Access Multiple Input Multiple Output (MIMO) wireless communication system is first described. For convenience of description, the uplink multi-user MIMO asynchronous communication system has the same number of antennas per user, which is Nt, the number of base station antennas is Nr, and the total number of users is L. The relative delay of each user signal is ·, in order not to lose generality. Let the relative delay of each user satisfy ^{0≡ ≡1} ^{^^'' } ^≤ ^ ^≤ 〜 ^≤ ^ ^≡匪„"'3⁄4}. Let ^α ^ ^{, τ} , where L « " denotes the nearest integer. For user k, set its multipath channel memory length (with the chip period Tc as the interval), its "4 艮 antenna to base station" The impulse response of the frequency selective channel between the 4 艮 antennas is

Where the complex-valued random variable ^h (( represents the first tap coefficient. Each user's coded symbol data stream is first serial-to-parallel transformed to form a Nt-column parallel data stream, and then spread using the user's spreading code, different users The data stream uses different spreading codes. Let the user's "4" antenna transmit a sequence of symbols of length N per frame.

Referring to FIG. 2, for each frame, each symbol is added with a cyclic prefix of length symbol before spreading, where ^ satisfies ≥^, , '''' }+ legs to obtain a symbol sequence of each frame added to the cyclic prefix. Yes, ie

• 's ^+N . Here we assume that there is w ^≥ . Extend the sequence as shown in Figure 2.

--ι Μ-ι

To the spread spectrum sequence "'^^("^"'(" — - ), where) is user _k The spreading code sequence, ^Π is the chip waveform, ^Q is the spreading gain, = ^M symbol period ^2. For each frame signal, the time [ ⁺ ^^ ⁺ ^), the base station's "4" antenna received signal is

For additive noise. As shown in FIG. 3, the received signal of each frame of the signal antenna base station is sampled at a chip rate, the observation window is synchronized with the signal of the user 1, and the received signal corresponding to the guard interval is rounded off. The sampling signal is

(»3⁄4") =∑∑∑3⁄4 ⁽ⁱ l,« if)'c _k {n)b ^k _M {ma _k一

: Ml in w = 0,l"'g-1,??2 = ^,^+1''',^- l,"r = 2 "'7Vr n _nr (m,n) = n _nr {L _{_{_{g T c + nMT c + T}}} c) sampling signal recombination extracted W

Despreading with user k spreading code ^+^' ¹ ...,^ ² — ^ for ^)

Where ^z ('") = [" ( ^w ' ⁰ ) ( ^w ' ⁷ ) '···'" 2 - ⁷ )] * is the despread noise. As can be seen from (4), only the signal There is interference between the inter-symbol interference (ISI) caused by the frequency selective channel and the signal between the respective transmitting antennas of the user k, and there is no more interference between the individual user signals. The interference between the antennas can be used. The LSFE-layered space frequency equalization algorithm described below is eliminated.

For all ⁺¹ , '", ^M - ¹ can get the corresponding ^r ( ^m ), which is represented as a vector form

_e c*'. Sequence ^ _N-point _DFT to obtain

= [ . (0) (ι),···, (N-i)T

(5)

which is

, where F is a normalized N-point Fourier transform matrix, which can be expressed as:

The DFT of the present invention employs a fast algorithm. There are

(") = OO) 'exp + 0)

(7)

N point DFT

Performing the above processing on all antenna received signals to obtain O ⁼¹ , ² , . . . , "^ ¹ , ² , . . . , ^, and performing DFT on the estimated impulse response of each channel to obtain a frequency domain signal. For a user k, take out The signals corresponding to the frequency point n are recombined to obtain a representation in the form of a matrix as follows:

R ^k (n) = R ^k (n). ^k (n) + Z ^k (n) _{(8 )}

Where R*(")«("),^("), , Zf(«)=[Z» ... (

Similar to the layered space-time equalization under the flat fading channel, the traditional optimal sequencing serial interference cancellation detection algorithm is applied to the frequency domain equalization, and the MIM0 frequency domain signal is detected by the single-carrier frequency domain equalizer. The multi-antenna single-carrier frequency-domain equalization coefficient can be based on the following two criteria:

W _Z (n) = {H(n)"R"' _Ar (K)H(«)}" ¹ H(«) ^W R' ^l _N (m) n = 0,1,···,Ν

(9) According to the minimum mean square error criterion:

W { (n) ^H R ¹ (n) H(") +R- ¹ {nf U(n) ^H

Wherein w ""_'OT) for the filter coefficient _W i _ener,

It can be proved that since the Fourier transform is a 酉 transform, the correlation matrix of the frequency domain signal is the same as the correlation matrix of the time domain signal. The algorithm is also applicable to various situations in which the transmit antenna power is not equal, the receive antenna's noise power is not equal, or the correlation and transmit antenna data are related. The i-th row of ^W W corresponds to the frequency domain equalization coefficient of the i-th transmit antenna at the n-th frequency point. I-th hair The frequency domain estimation signal of the antenna can be expressed as

, (") = [w(")] _{(i :} )R(") ' « = o,i,-.,Ni where [ ^w (" , _:) is the ith line of [w(")]. The frequency domain estimation signal of the multi-transmitting antenna is detected by the frequency division point of the single carrier frequency domain equalizer. The frequency domain estimation signal of each transmitting antenna is transformed into a time domain signal by an inverse Fourier transformer, and then the user obtains the Decision signal for each transmit antenna.

The optimal ordering is based on the average signal-to-noise-and-interference ratio (SINR) of the signal transmitted by the user k after the frequency domain equalizer detects. The average signal-to-noise-and-interference ratio (SINR) of the frequency domain signals of each of the user k transmit antennas after being detected by the frequency domain equalizer can be directly obtained as -

: ^R _D (")1

丄∑——

(12)

[ n = -,N-\ ₍₁₃ )

When satisfied (")

When ( ₁₂₎ and ₍₁₃₎ can be simplified to

(15)

Where ^W " represents the i-th row and j-th column element of the matrix, L H' ^j ('', ^:) represents the i-th row of the matrix, represents the modulus of the complex number, I represents the 2-norm of the vector, "represents the N-order identity matrix . According to the above, the present invention first provides a signal transmission method for a multi-user mobile communication system, comprising the following steps: (1) mapping a user information bitstream into a symbol sequence;

(2) decomposing the mapped symbol sequence into a multiplex symbol sequence;

(3) adding a cyclic prefix to each of the decomposed symbol sequences;

(4) Allocating system code resources to users (groups);

(5) generating a spreading code chip according to the allocated system code resource;

(6) Multiplying the symbol sequences of the respective paths added to the cyclic prefix by the chips to obtain a data frame and transmitting. Correspondingly, the present invention also provides a signal receiving method for a multi-user mobile communication system, including the following steps:

(4) Calculating the equalization coefficients of the frequency domain equalizers of all currently undetected transmit antennas at each frequency point according to the frequency domain received signals of the reassembled user (group) and the frequency domain response of each channel ;

(5) calculating an average signal-to-noise-to-interference ratio on all currently undetected transmit antennas, determining a currently-transmitted transmit antenna based on the order of the signal-to-noise-interference ratio, and correcting the current determined one based on the obtained equalization coefficient Detecting a transmit antenna for equalization, and obtaining an estimated frequency domain signal of the transmit antenna;

(6) performing inverse frequency estimation on the frequency domain signal estimation value of the currently detected transmitting antenna The leaf transforms, and determines a decision value of the corresponding transmit antenna transmission data according to the transformed signal;

The step (11) may include:

(IIA) performing data recombination on the decision value corresponding to the transmission data of all transmitting antennas;

(I IB) The data recombined data is subjected to parallel conversion to obtain the transmission data of the user (group). The present invention also provides a signal receiving method of another multi-user mobile communication system, comprising the following steps:

(2) performing a Fourier transform on the separated time domain received signals of the user (group), Transforming into a frequency domain receiving signal of the user (group), and performing data reconstruction on the frequency domain receiving signal of the user (group) after the transformation;

(10) re-executing the steps (4)-(10) according to the new frequency domain received signal of the user (group) and the new frequency domain response of each channel, and sequentially iterating through the signals between the antennas until After all the transmitting antennas are detected, the detection order of all the transmitting antennas is obtained as ^···, '; and the detection order of the transmitting antennas is recorded, and the equalizer coefficients of the corresponding transmitting antennas corresponding to the order are recorded;

(11) Using the transmitted data sequence of the last detected transmit antenna as the known interference of the transmit data stream of other transmit antennas, serial interference cancellation for each layer in the order of —>^—〉...―> ^ Dividing and using the equalizer coefficients obtained last time to reconstruct the interference signal, obtaining a new detected symbol sequence of all transmitting antennas, and recording the equalizer coefficients corresponding to the transmitting antenna detecting order in the process;

(12) If the obtained new data sequence ⁶ of the last detected transmitting antenna is the same as the result of the previous detection, or the number of measured iterations reaches the requirement, the iteration is terminated, and the final detection result is obtained;

(13) The detection result of all the antennas is passed through a parallel-serial converter to obtain the transmission data of the user (group).

The step (13) may include:

(13A) performing data recombination on the decision value corresponding to the transmission data of all transmitting antennas;

(13B) The data recombined data is subjected to parallel conversion to obtain transmission data of the user (group). Referring to Figures 3 and 4, the two figures depict a block diagram of Embodiment 1 of the present invention. The transmitter using this example, as shown in FIG. 3, includes a user information bit stream generator, a symbol mapper, a demultiplexer, a cyclic prefix generator, a system code resource allocator, a spreading code sequence generator, and a multiplier .

The user information bit stream generator is configured to generate a user information bit stream; a symbol mapper is configured to map the user information bit stream into a symbol sequence; and a demultiplexer is configured to decompose the mapped symbol sequence a multiplexed symbol sequence; a cyclic prefix generator for adding a cyclic prefix to each of the decomposed symbol sequences; a system code resource allocator for allocating system code resources; and a spreading code generator for assigning a system code resource, generating a spreading code chip; a multiplier, configured to multiply the symbol sequences of the respective paths added to the cyclic prefix by the chip to obtain a data frame.

Wherein, the multiplier described in the present transmitter performs a spreading function, which is different from a common chip sequence multiplied by a symbol, which is multiplied by a symbol sequence by a symbol sequence. At the receiving end, by recombining and despreading the sampled values of the signals, the signals of users using different codewords can be completely used first. Separation, so that the common channel interference is completely eliminated.

The cyclic prefix generator described in the present transmitter may be replaced by a zero-adding technique by adding a cyclic prefix. These two techniques are used to eliminate interference between data blocks caused by frequency selective fading channels and uplink asynchronous communication. The common channel interference between the user signals is also to construct the cyclicity of the matrix. Here, the zero-adding technique means that the transmitting end adds zeros after the transmitted data block, and the receiving end rejects the last detected zero data after detecting the received data block.

In addition to the allocation according to the existing code resource allocation method, the system code resource allocator in the transmitter may also divide the users into a group when the total number of antennas of several users in the system is not greater than the number of receiving antennas. The group is assigned the same spreading code. All users in this group use this same spreading code to spread the transmitted data stream. Think of all users and base stations in each group as a virtual MIMO communication system. At the receiving end, by recombining and despreading the sampled values of the signals, the signals of the group of users can be completely separated from the signals of other groups of users, thereby reducing co-channel interference between users.

The transmitter data processing flow can be described as -

(1) The user information bit stream is first mapped to a symbol sequence by a symbol mapper;

(2) Dividing the mapped symbol sequence into Nt path data through a demultiplexer;

(3) adding each symbol sequence to the cyclic prefix through the cyclic prefix generator;

(4) The symbol sequence added to the cyclic prefix is passed through a multiplier, and the code generated by the spread code generator is multiplied by the symbol sequence to obtain a data frame. As shown in FIG. 4, the receiver according to this embodiment is composed of a cyclic prefix remover, a data reassembler, a despreader, a first, a second Fourier transform unit, a channel estimator, and first and second data. The recombiner, the frequency domain equalizer equalization coefficient calculation unit, the sequencing and frequency domain equalization unit, the inverse Fourier transform unit, the channel recovery unit, the interference canceller, the parallel-to-serial transform unit, and the decider are composed.

The cyclic prefix canceller is configured to cancel the time domain signal received by the corresponding receiving antenna. The cyclic prefix in the data;

a first data recombiner, configured to reassemble the signal data after canceling the cyclic prefix; a despreader, configured to despread the reassembled signal in a time domain, and receive a specific user's received signal with other users Separating the signal to obtain a time domain received signal of the user;

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to transform the separated time domain received signal of the user and each channel impulse response estimated by the channel estimator into a frequency domain received signal of the user and a frequency of each channel Domain response

a second data recombiner, configured to recombine the frequency domain received signal data received by each of the receiving antennas of the user and transformed by the corresponding first Fourier transform unit;

a frequency domain equalizer coefficient calculating unit, configured to calculate, according to the user frequency domain received signal and a frequency domain response of each channel, an equalization coefficient of a frequency domain equalizer of all transmitting antennas at each frequency point;

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; and a determiner configured to determine the signal subjected to the inverse Fourier transform to obtain a decision value of the data corresponding to the transmit antenna of the user;

An interference canceller, configured to cancel the reconstructed interference signal and the reassembled frequency domain received signal of the user, to obtain a new frequency domain received signal of the user, and to use the channel frequency The channel response vector corresponding to the current detecting antenna in the domain response matrix is set to zero, and a new frequency domain response of each channel is obtained, and the new frequency domain received signal of the user and the new frequency domain response of each channel are returned to the frequency. Domain equalizer coefficient calculation unit;

The parallel-serial converter is configured to perform parallel-to-serial conversion on the decision value corresponding to the transmission data of all the transmitting antennas to obtain the transmission data of the user. The receiver data processing flow can be described as:

(1) All receiving antennas receive the time domain signal through the cyclic prefix canceller to round off the cyclic prefix; the signal after the de-cyclic prefix is reorganized by the data recombiner, and the recombined signal is despread in the time domain to receive a user. The signal is separated from other user signals;

(2) converting the separated user time domain received signal and each channel impulse response estimated by the channel estimator into a frequency domain signal by a Fourier transform unit;

(3) Calculating the equalization coefficients of the frequency domain equalizers of all transmitting antennas at respective frequency points according to the frequency domain received signals of the frequency domain and the frequency domain response of the channel;

(4) The average signal-to-noise-and-interference ratio (SINR) on each of the remaining transmit antennas after the calculation in the sequencing and frequency-domain equalization unit is performed, and the signal-to-noise ratio is sorted to determine the currently transmitting transmit antenna;

(5) using a frequency domain equalizer in the ordering and frequency domain equalization unit to equalize the transmit antenna signal having the largest signal to noise interference ratio to obtain a frequency domain signal estimated value of the transmit antenna;

(6) passing the frequency domain estimation value through an inverse Fourier transform unit and a decider to obtain a decision value of the data transmitted by the user corresponding to the transmitting antenna;

(7) The decision data is taken as an output, and is transformed into a frequency domain signal by a Fourier transform unit, and the channel frequency domain response vector corresponding to the transmit antenna is obtained by the channel recovery unit (ie, ^{H of} (8)) Multiplying the column vector of the transmitting antenna) to reconstruct the interference signal of the transmitting antenna in the frequency domain;

(8) In the interference canceller, cancel the recovered interference signal and the frequency domain received signal, reduce the interference of the transmit antenna signal on other antenna signals in the received signal, and obtain a new frequency domain received signal; (9) Zeroing the channel response vector corresponding to the detected antenna in the channel response matrix to obtain a new channel frequency domain response matrix;

(10) The new frequency domain received signal and the frequency domain response matrix parameter of the channel are returned to the frequency domain equalizer equalization coefficient calculation unit to process the signal of the suboptimal antenna, and the signal is again subjected to the frequency domain equalizer equalization coefficient calculation unit, sequencing and frequency domain equalization. Unit, inverse Fourier transform unit (IFFT), decider, Fourier transform unit (FFT), channel recovery unit, interference canceller processing, generating new frequency domain received signals and channel frequency domain response matrix parameters return frequency domain equalization The equalization coefficient calculation unit processes the signal of the better antenna, and repeats the sequence of the signals between the antennas until all the transmitting antennas are detected;

(11) The detection signals of all the antennas are passed through the parallel-serial converter to obtain the transmission data of the user. Referring to Figures 3 and 5, the two figures depict a block diagram of Embodiment 2 of the present invention. The transmitter using this example includes a user information bit stream generator, a symbol mapper, a demultiplexer, a cyclic prefix generator, a system code resource allocator, a spreading code sequence generator, and a multiplier.

As shown in FIG. 5, the receiver includes a cyclic prefix remover, first and second data reassemblers, a despreader, first and second Fourier transform units, a channel estimator, an optimal detection sequence memory, and an equalizer coefficient. Memory, iteration count counter, forward serial interference canceller, reverse serial interference canceller, comparator, frequency domain equalizer equalization coefficient calculation unit, sequencing and frequency domain equalization unit, inverse Fourier transform unit, channel recovery unit, Interference canceller, parallel-to-serial conversion unit, decider, first and second memories.

The cyclic prefix canceller is configured to eliminate a cyclic prefix in the time domain signal data received by the corresponding receiving antenna;

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to receive the separated time domain of the user and Each channel impulse response estimated by the channel estimator is respectively transformed into a frequency domain received signal of the user and a frequency domain response of each channel;

a first memory, configured to store a decision value output by the decider;

An interference canceller, configured to cancel the reconstructed interference signal and the reassembled frequency domain received signal of the user, to obtain a new frequency domain received signal of the user, and to use the frequency domain response matrix of each channel The channel response vector corresponding to the current detecting antenna is set to zero, and a new frequency domain response of each channel is obtained, and the new frequency domain receiving signal of the user and the new frequency domain frequency domain response are returned to the frequency domain equalizer. Coefficient calculation unit;

An optimal detection sequence memory for storing sequential iterations of signals passing between antennas until all transmission antennas are detected, and the obtained antenna detection sequence is H"'^; An equalizer coefficient memory, configured to store an equalization coefficient of a corresponding transmit antenna calculated in the sequential iterative process;

Forward serial interference canceller, used to transmit the data sequence of the last detected transmit antenna as the known interference of the transmit data stream of other transmit antennas, serialize each layer in the order of >>"'-> Interference cancellation, obtaining a new sequence of detected symbols for all transmit antennas; a comparator for comparing the resulting new data sequence of the last detected transmit antenna with the result of the last test stored in the first memory If the comparison is the same, stop iteration;

a second memory, configured to record a final measurement result when the iteration is stopped; and a parallel-serial converter for performing parallel-to-serial conversion on the final measurement result to obtain transmission data of the user. The sender data processing flow can be described as:

(2) dividing the mapped symbol sequence into Nt road data through a demultiplexer;

(3) adding each symbol sequence to the cyclic prefix through a cyclic prefix generator;

(4) The symbol sequence added to the cyclic prefix is passed through a multiplier, and the code generated by the spread code generator is multiplied by the symbol sequence to obtain a data frame.

The receiver data processing flow can be described as:

(3) Calculating the output of all the transmitting antennas based on the frequency domain response of the received signals in the frequency domain and the channel The equalization coefficient of the frequency domain equalizer at each frequency point;

(5) using a frequency domain equalizer in the ordering and frequency domain equalization unit to equalize the transmit antenna signal having the largest signal to noise interference ratio to obtain an estimated frequency domain signal of the transmit antenna;

(7) The decision data is taken as an output, and is transformed into a frequency domain signal by a Fourier transform unit, and the channel frequency domain response vector corresponding to the transmit antenna is matched by the channel recovery unit (ie, (8) Multiplying the column vector of the transmitting antenna to reconstruct the interference signal of the user of the transmitting antenna in the frequency domain;

(8) In the interference canceller, cancel the recovered interference signal and the frequency domain received signal, reduce the interference of the transmitting antenna signal on other antenna signals in the received signal, and obtain a new frequency-domain received signal after interference cancellation. ;

(9) Zeroing the channel response vector corresponding to the detected antenna in the channel response matrix to obtain a new channel frequency domain response matrix;

(10) The new frequency domain received signal and the frequency domain response matrix parameter of the channel are returned to the frequency domain equalizer equalization coefficient calculation unit to process the signal of the suboptimal antenna, and the signal is again subjected to the frequency domain equalizer equalization coefficient calculation unit, sequencing and frequency domain equalization. Unit, inverse Fourier transform unit (IFFT), decider, Fourier transform unit (FFT), channel recovery unit, interference canceller processing, generating new frequency domain received signals and channel frequency domain response matrix parameters return frequency domain equalization The equalization coefficient calculation unit processes the signal of the superior antenna again, and repeats the sequence of the signals between the antennas until all the transmitting antennas are detected, and the optimal detection order is -1 '. In the process, the optimal detection order is stored in the optimal detection sequence memory and the equalizer coefficients corresponding to the sequence are stored in the equalizer coefficient memory;

(11) Using the last detected transmit antenna data sequence as the known interference of other data streams, applying serial interference cancellation to each layer in the forward serial interference canceller in the order of 〉'^ Dividing, a new sequence of detected symbols for all transmit antennas is obtained; in the process, equalizer coefficients corresponding to the sequence are stored in the equalizer coefficient memory;

(12) If the obtained last detected transmit antenna data sequence ⁶ is the same as the result of the last detection after comparison by the comparator or the number of iterations measured by the iteration number counter reaches the requirement, the iteration is terminated, and the final detection result is obtained; Unlike the previous one, ⁴ ' is known as the new other data stream, and the reverse serial interference canceller is re-detected in the order of 〉^+';

(13) After returning the result of the re-detection to the first layer antenna, the detection process is repeated until the final detection result is obtained;

(14) The detection signals of all the antennas are passed through a parallel-serial converter to obtain the transmission data of the user.

Now consider that when the sum of the number of transmitting antennas of several users in the system is not greater than the number of receiving antennas of the base station, these users can be grouped into one group, and each group is assigned a spreading code. All users in the group use the same The spreading code spreads the transmitted data stream. For the sake of generality, the total number of users is = GxM, and all users are divided into G groups, and the number of users in each group is

M. The number of base station receiving antennas Nr satisfies ^σ - ^{Μ =} ^· ^{Μ ≤} ^Λ ''. Think of all users and base stations in each group as a virtual communication system. Use ⁽ g, for the p-th user of the g-th group.

As mentioned above, at the receiving end, the received signal is first sampled, and the sampled values are recombined to obtain a vector « = G, , N - 1, and then despread by the unique spreading code assigned to each group. The signal does not have co-channel interference of different groups of user signals, but only inter-symbol interference caused by the frequency selective channel and interference of signals between the respective transmitting antennas of all users in the same group. Transforming the despread signal into the frequency domain yields ^{RSW =} [^ '^(")'"'^»]. Where N'

^Z (W is the _defect _DFT . = [H(„ '^2>("),-·.,Η(')(")] + z ₂ (")

R ^g (n) = U ^g (n) ^g (n) +Z ^g (n) Z ^s _Nr (n)_

(17)

W ₂ .M (")

W (n) = R (n), R ^g ₂ («), · · -, R ^g _Nl . (n)JB ^(s '"» («) = [5< ^s '"», («) B ^M ₂ (n) - B

Referring to Fig. 3 and Fig. 6, Fig. 2 is a structural view showing a third embodiment of the present invention. The transmitter using this example includes a user information bit stream generator, a symbol mapper, a demultiplexer, a cyclic prefix generator, a system code resource allocator, a spreading code sequence generator, and a multiplier.

As shown in FIG. 6, the receiver includes a cyclic prefix remover, first, second, third data reassemblers, despreaders, first and second Fourier transform units, channel estimators, and frequency domain equalizer equalization coefficients. Computation unit, sorting and frequency domain equalization unit, inverse Fourier transform unit, channel recovery unit, interference canceller, parallel-to-serial conversion unit, and decider.

a first data recombiner, configured to recombine the signal data after canceling the cyclic prefix; a despreader, configured to despread the reassembled signal in a time domain, and receive signals of a specific user group with other The user group signal is separated, and the time domain receiving signal of the user group is obtained;

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to convert the separated time domain received signal of the user group and each channel impulse response estimated by the channel estimator into a frequency domain received signal and each channel of the user group, respectively Frequency domain response;

a second data recombiner, configured to recombine frequency domain received signal data received by each receiving antenna of the user group and transformed by the corresponding first Fourier transform unit;

a frequency domain equalizer coefficient calculating unit, configured to calculate, according to the frequency domain received signal of the user group and the frequency domain response of each channel, calculate frequency domain equalizers of all transmitting antennas at respective frequency points Equalization coefficient

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; a determiner, configured to determine, according to the inverse Fourier transform signal, a decision value of the transmit data corresponding to the transmit antenna of the user group;

An interference canceller, configured to cancel the reconstructed interference signal and the reassembled frequency domain received signal of the user group, to obtain a new frequency domain received signal of the user group, and to use the frequency domain of each channel The channel response vector corresponding to the current detection antenna in the response matrix is set to zero, and a new frequency domain response of each channel is obtained, and the new frequency domain received signal of the user group and the new frequency domain response of each channel are returned to the frequency. Domain equalizer coefficient calculation unit;

a third data recombiner, configured to perform data recombination of the decision value (after the data is reorganized, the specific user can be separated from the group), and then enter the parallel-to-serial converter;

A parallel-serial converter is used to perform parallel-to-serial conversion of the data after data recombination to obtain the transmission data of the user. The sender data processing flow can be described as:

(3) adding each symbol sequence to the cyclic prefix through a cyclic prefix generator; (4) The symbol sequence added to the cyclic prefix is passed through a multiplier, and the code generated by the spread code generator is multiplied by the symbol sequence to obtain a data frame.

The receiver data processing flow can be described as - (1) all receiving antennas receive the time domain signal through the cyclic prefix canceller to round off the cyclic prefix; the signal after the de-cyclic prefix is reorganized by the data recombiner, and the recombined signal is in time Domain despreading, separating the received signals of the group of users from other group user signals;

(2) converting the separated time domain received signal and each channel impulse response estimated by the channel estimator into a frequency domain signal by a Fourier transform unit;

(3) calculating, according to the frequency domain received signal and the frequency domain response of the channel, the equalization coefficients of the frequency domain equalizers of all the transmitting antennas of the group at each frequency point;

(6) passing the frequency domain estimation value to the decision value of the data transmitted by the corresponding transmitting antenna through the inverse Fourier transform unit and the decider;

(7) The decision data is taken as an output, and the channel is transformed into a frequency domain signal by a Fourier transform unit, and the channel frequency domain response vector corresponding to the transmit antenna is obtained by the channel recovery unit (ie, (17) (") Multiplying the column vector of the corresponding transmitting antenna to reconstruct the interference signal of the transmitting antenna in the frequency domain;

(8) In the interference canceller, the recovered interference signal is cancelled with the frequency domain received signal, and the interference of the transmitting antenna signal on the transmitted signals of other antennas in the received signal is reduced, and a new frequency domain received signal is obtained;

(9) Zeroing the channel response matrix (ie, ^HS (") of equation (17) corresponding to the channel response vector of the detected antenna to obtain a new channel frequency domain response matrix;

(10) The new frequency domain received signal and the frequency domain response matrix parameter of the channel return to the frequency domain equalizer equalization coefficient calculation unit to process the signal of the suboptimal antenna, and the signal re-passes the frequency domain equalizer Balance coefficient calculation unit, sorting and frequency domain equalization unit, inverse Fourier transform unit (IFFT), decider, Fourier transform unit (FFT), channel recovery unit, interference canceller processing, generating new frequency domain received signals and channels The frequency domain response matrix parameter returns the frequency domain equalizer equalization coefficient calculation unit to process the signal of the better antenna, and repeats the sequence of the signals between the antennas until all the transmitting antennas are detected;

(11) The detection signals of all antennas are sent by the data recombiner and the parallel-serial converter to obtain the transmission data of all users in the group, and each user's data is separated separately. Referring to Fig. 3 and Fig. 7, Fig. 2 is a structural view showing a fourth embodiment of the present invention. The transmitter using this example includes a user information bit stream generator, a symbol mapper, a demultiplexer, a cyclic prefix generator, a system code resource allocator, a spreading code sequence generator, and a multiplier.

The receiver includes a cyclic prefix remover, first, second, third data reassemblers, despreaders, first and second Fourier transform units, channel estimator, optimal detection order memory, equalizer coefficient memory, iteration Count counter, forward serial interference canceller, reverse serial interference canceller, comparator, frequency domain equalizer equalization coefficient calculation unit, sequencing and frequency domain equalization unit, inverse Fourier transform unit, channel recovery unit, interference cancellation , parallel-to-serial conversion unit, decider, first and second memories.

The first data reassembler is configured to reassemble the signal data after the cyclic prefix is eliminated;

a despreader, configured to despread the reassembled signal in a time domain, and separate a received signal of a specific user group from other user group signals to obtain a time domain received signal of the user group;

a channel estimator for estimating an impulse response of each channel;

a second data recombiner, configured to recombine the frequency domain received signal data received by each receiving antenna of the user group and transformed by the corresponding first Fourier transform unit; a frequency domain equalizer coefficient calculating unit, configured to calculate, according to the frequency domain received signal of the user group and the frequency domain response of each channel, an equalization coefficient of a frequency domain equalizer of all transmitting antennas at each frequency point;

a first memory, configured to store a decision value output by the decider;

The optimal detection sequence memory is used for storing the sequential iterations of the signals passing between the antennas until the detection of all the transmitting antennas is completed, and the obtained antenna detection order is ^"';

The forward serial interference canceller is configured to use the transmitted data sequence of the last detected transmit antenna as a known interference of other data streams, and serialize each layer in the order of ^>->...-> Interference cancellation, obtaining a new sequence of detected symbols for all transmit antennas;

a comparator, configured to compare the obtained new data sequence of the last detected transmit antenna with the result of the last detection stored in the first memory, and if the comparison is the same, stop the iteration;

a reverse serial interference canceller for notifying that the new data sequence ^{0 of the} last detected transmit antenna is different from the result of the last detection stored in the first memory, and the number of iterations does not meet the requirement, ⁶ ^ As a new known interference, re-test each layer in the order of ―〉^―〉...->;

a second memory, configured to record a final measurement result when the iteration is stopped; a third data reorganizer for reorganizing the decision value (after the data is reorganized, the specific user can be separated from the group) Re-entering the parallel-to-serial converter;

A parallel-serial converter is used to perform parallel-to-serial conversion of the final measurement result after the recombination to obtain the transmission data of the user. The sender data processing flow can be described as:

(2) The separated time domain received signal and the channel impulse response estimated by the channel estimator Transformed into a frequency domain signal by a Fourier transform unit;

(3) calculating, according to the frequency domain received signal and the frequency domain response of the channel, the equalization coefficients of the frequency domain equalizers of all the transmitting antennas of all users in the group at each frequency point;

(7) The decision data is taken as an output, and is transformed into a frequency domain signal by a Fourier transform unit, and the channel frequency domain response vector corresponding to the transmit antenna is matched by the channel recovery unit (ie, (17) Multiplying the column vector of the transmitting antenna to reconstruct the interference signal of the transmitting antenna in the frequency domain;

(9) Zeroing the channel response matrix corresponding to the detection antenna in the channel response matrix (ie, ^Hg W of equation (17)) to obtain a new channel frequency domain response matrix;

(10) The new frequency domain received signal and the frequency domain response matrix parameter of the channel are returned to the frequency domain equalizer equalization coefficient calculation unit to process the signal of the suboptimal antenna, and the signal is again subjected to the frequency domain equalizer equalization coefficient calculation unit, sequencing and frequency domain equalization. Unit, inverse Fourier transform unit (IFFT), decider, Fourier transform unit (FFT), channel recovery unit, interference canceller processing, generating new frequency domain received signals and channel frequency domain response matrix parameters return frequency domain equalization The equalization coefficient calculation unit processes the signal of the better antenna, and repeats the sequence of the signals between the antennas until all the transmitting antennas are detected, and the optimal detection order is

-... A, , e{l,2, . , G_N. Storing the optimal detection order in the optimal detection order memory and storing the equalizer coefficients corresponding to the sequence in the equalizer coefficient memory; (11) Using the last detected transmit antenna data sequence ^D '| as the known interference of other data streams, apply serial interference to each layer in the forward serial interference canceller by pressing ^──────... Eliminating, obtaining a new sequence of detected symbols for all transmit antennas; storing equalizer coefficients corresponding to the sequence in the equalizer coefficient memory in the process;

(12) If the obtained last detected transmit antenna data sequence is the same as the result of the last detection after comparison by the comparator or the number of iterations measured by the iteration count counter reaches the requirement, the iteration is terminated, and the final test result is obtained; The last time is different, the interference will be known as the new other data stream, and the reverse serial interference canceller will re-detect in the order of >4; (13) After the result of the re-detection returns to the first layer antenna, the detection process is repeated. Until the final test result is obtained;

(14) The detection signals of all antennas are sent by the data recombiner and the parallel-serial converter to obtain the transmission data of all users in the group, and each user's data is separated independently. Industrial applicability

One of the detection methods for the multi-user multiple input multiple output (MIMO) system of the present invention is to use a single carrier frequency domain equalizer to combat various interferences caused by frequency selective fading, and to use layered space frequency detection. The algorithm, and an improved iterative layered space-frequency detection algorithm is used to reduce the impact of error propagation caused by serial interference cancellation. Using this detection method, not only the average performance of the system is good, but the implementation complexity is also low.

The computer simulation test shows that the present invention can reduce the computational complexity of the multi-user wireless communication system and further improve the performance of the system. In summary, the present invention is a flexible, practical, and efficient transmitter and receiver design and a low complexity multi-user signal guessing method for wideband multi-user multiple input multiple output (MIMO) systems.

Claims

Spur request

A signal transmission method for a multi-user mobile communication system, comprising the steps of:

Mapping a user information bitstream into a sequence of symbols;

Decomposing the mapped symbol sequence into a multiplex symbol sequence;

Adding a cyclic prefix to each of the decomposed symbol sequences;

Allocate system code resources to users (groups);

'Multiply the symbol sequences of the paths added to the cyclic prefix by the chips, respectively, to obtain a data frame and transmit.

2. The method of claim 1 wherein the step of adding a cyclic prefix comprises adding zero before or after the transmitted data block.

The method according to claim 1, wherein in the step of allocating system code resources, when the total number of antennas of several users in the system is not greater than the number of receiving antennas, the users may be grouped into groups. Each group is assigned the same spreading code.

A transmitter for a multi-user mobile communication system, comprising: a user information bit stream generator for generating a user information bit stream;

a symbol mapper, configured to map the user information bit stream into a symbol sequence;

a demultiplexer, configured to decompose the mapped symbol sequence into a multi-way symbol sequence; a cyclic prefix generator, configured to add a cyclic prefix to each of the decomposed symbol sequences; a system code resource allocator, configured to User (group) allocates system code resources;

And a spreading code generator, configured to generate a spreading code chip according to the allocated system code resource; and a multiplier, configured to multiply the symbol sequences added to the cyclic prefix by the respective channels by the code to obtain a data frame.

The transmitter according to claim 1, wherein said cyclic prefix generator, Add zero before or after the transmitted data block.

The transmitter according to claim 1, wherein the system code resource allocator divides the users into a group when the total number of antennas of the plurality of users in the system is not greater than the number of receiving antennas. One group assigns the same spreading code.

A signal receiving method for a multi-user mobile communication system, comprising the steps of:

(1) corresponding to each receiving antenna, respectively canceling the cyclic prefix in the time domain signal data received by each receiving antenna, respectively performing data recombination on the signal after eliminating the cyclic prefix, and separately recombining the signal in the time domain Despreading, separating the received signal of a specific user (group) from the received signals of other users (groups);

(4) Calculating the equalization coefficients of the frequency domain equalizers of all currently undetected transmit antennas at respective frequency points according to the frequency domain received signals of the reassembled user (group) and the frequency domain response of each channel. ;

(5) calculating an average signal-to-noise-to-interference ratio on all currently undetected transmit antennas, determining a currently-transmitted transmit antenna according to a sorting of the signal-to-noise-interference ratio, and determining the current current set according to the obtained equalization coefficient Detecting a transmit antenna for equalization, and obtaining an estimated frequency domain signal of the transmit antenna;

(7) taking the decision data as an output, and after one-way Fourier transform, transforming into a frequency domain signal, and converting the transformed frequency domain signal to a channel corresponding to the currently detected transmitting antenna Multiplying the frequency domain response vector to obtain an interference signal for reconstructing the transmitting antenna;

(10) re-executing the steps (4) - (10) according to the new frequency domain received signal of the user (group) and the new frequency domain response of each channel, and sequentially iterating through the signals between the antennas until All transmitting antennas are detected;

8. The method according to claim 7, wherein in the step (5), the undetected transmitting antenna having the largest signal to noise interference ratio is determined as the transmitting antenna to be detected.

The method according to claim 7, wherein the step (11) comprises: (11A) performing data recombination on a decision value corresponding to the transmit data of all transmit antennas;

(11B) The data recombined data is subjected to parallel conversion to obtain transmission data of all users in the group, and each user's data is independently separated.

A receiver for a multi-user mobile communication system, comprising: a cyclic prefix canceller, configured to cancel a cyclic prefix in time domain signal data received by a corresponding receiving antenna;

a first data recombiner, configured to reassemble the signal data after canceling the cyclic prefix; and a despreader for despreading the reassembled signal in a time domain to receive a specific user (group) Separating from other user (group) signals to obtain a time domain received signal of the user (group);

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to receive the separated time domain of the user (group) The signal and each channel impulse response estimated by the channel estimator are respectively transformed into a frequency domain received signal of the user (group) and a frequency domain response of each channel;

a second data recombiner, configured to recombine the frequency domain received signal data received by each receiving antenna of the user (group) and transformed by the corresponding first Fourier transform unit;

a frequency domain equalizer coefficient calculation unit, configured to calculate, according to the user (group) frequency domain received signal and a frequency domain response of each channel, an equalization coefficient of a frequency domain equalizer of all transmit antennas at each frequency point;

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; a determiner, configured to determine, according to the inverse Fourier transformed signal, a decision of the user (group) corresponding to the transmitting antenna to send data Value

An interference canceller, configured to cancel the reconstructed interference signal and the recombined frequency domain received signal of the user (group) to obtain a new frequency domain receiving signal of the user (group), The channel response vector corresponding to the current detecting antenna in each channel frequency domain response matrix is set to zero, and a new frequency domain response of each channel is obtained, and the user (group) new frequency domain receiving signal and the new channel frequency are obtained. The domain response returns the frequency domain equalizer coefficient calculation unit;

The parallel-serial converter is configured to perform parallel-to-serial conversion of the decision values corresponding to the transmission data of all the transmitting antennas to obtain the transmission data of the user (group).

11. The receiver of claim 10, wherein said ordering and frequency domain are both The weighing unit determines the undetected transmitting chirp line with the largest signal-to-noise interference ratio as the transmitting antenna to be detected.

The receiver according to claim 10, further comprising: a third data recombiner, configured to perform the decision value before performing parallel-to-serial conversion of the decision values corresponding to the transmission data of all the transmitting antennas The data is recombined and then entered into the parallel-to-serial converter.

(3) estimating the impulse response of each channel, and performing Fourier transform on each of the estimated signal impulse responses, 'converting into a frequency domain response;

(6) performing an inverse Fourier transform on the frequency domain signal estimation value of the currently detected transmit antenna, and determining a decision value of the corresponding transmit antenna transmit data according to the transformed signal; (7) taking the decision data as an output, and after one-way Fourier transform, transforming into a frequency domain signal, and multiplying the transformed frequency domain signal by a channel frequency domain response vector corresponding to the currently detected transmitting antenna, Reconstructing the interference signal of the transmitting antenna;

(10) re-executing the steps (4) - (10) according to the new frequency domain received signal of the user (group) and the new frequency domain response of each channel, and sequentially iterating through the signals between the antennas until All the transmitting antennas are detected, and the detection order for all transmitting antennas is

^Zn W and recording the detection order of the transmitting antennas, and the equalizer coefficients of the corresponding transmitting antennas corresponding to the order;

(ID uses the transmitted data sequence ^{0 of the} last detected transmit antenna as the known interference of the transmit data stream of the other transmit antennas, performs serial interference cancellation on each layer in the order of 4 ->..., and uses the last obtained equalization. The coefficients are used to reconstruct the interference signal to obtain a new sequence of detected symbols for all of the transmitting antennas, and in the process, the equalizer coefficients corresponding to the transmitting antenna detection order are recorded;

(12) If the obtained new data sequence ⁴ of the last detected transmitting antenna is the same as the result of the previous detection, or the number of measured iterations reaches the requirement, the iteration is terminated, and the final detection result is obtained;

(13) The transmission result of the user (group) is obtained by passing the detection results of all the antennas through the parallel-serial converter.

14. The method as claimed in claim 13, wherein said step (12), if the detection result is not the same, and does not reach the required number of iterations, as will a new ^¾ known interference, to obtain the use of a The equalizer coefficients are used to reconstruct the interference signals, and each layer is re-detected in the order of ^ _〉 '_>...―>.

15. The method according to claim 13, wherein in the step (5), The undetected transmitting antenna having the largest signal to noise interference ratio is determined as the transmitting antenna to be currently detected.

The method according to claim 13, wherein the step (13) includes:

(13B) The data recombined data is parallel-converted to obtain transmission data of all users in the group, and each user's data is separately separated.

a first data recombiner, configured to reassemble the signal data after canceling the cyclic prefix; and a despreader for despreading the reassembled signal in a time domain to receive a specific user (group) Separating from other user signals (groups) to obtain a time domain receiving signal of the user (group);

a channel estimator for estimating an impulse response of each channel;

a first Fourier transform unit, configured to transform the separated time domain received signal of the user (group) and each channel impulse response estimated by the channel estimator into a frequency domain of the user (group) Receiving signals and frequency domain responses of each channel;

a sorting and frequency domain equalization unit, configured to calculate an average signal-to-noise interference ratio on all currently undetected transmit antennas, determine a currently-transmitted transmit antenna according to a sort of the signal-to-noise-interference ratio, and obtain a balance coefficient according to the obtained The currently detected transmit antenna is equalized to obtain the transmit Estimating the frequency domain signal of the antenna;

An inverse Fourier transform unit, configured to perform an inverse Fourier transform on the frequency domain estimation value; and a determiner configured to determine the signal subjected to the inverse Fourier transform to obtain a judgment of the user (group) corresponding to the transmit antenna transmitting data Value

a first memory, configured to store a decision value output by the decider;

The optimal detection sequence memory is used for storing the sequential iterations of the signals passing between the antennas until the detection of all the transmitting antennas is completed, and the obtained antenna detection order is ^^―,,...,^;

A forward serial interference canceller for using the transmitted data sequence of the last detected transmit antenna as a known interference of the transmit data stream of other transmit antennas, and performing serial interference on each layer in the order of ' 〉〉 ' Eliminate, get a new sequence of detected symbols for all transmit antennas;

An iteration number counter, used to record the number of iterations, and when the number of iterations measured reaches the requirement, the iteration is stopped; a second memory, configured to record a final measurement result when the iteration is stopped, and a parallel-serial converter for performing parallel-to-serial conversion of the final measurement result to obtain transmission data of the user (group).

18. The receiver of claim 17, further comprising: a reverse serial interference canceller for storing a new data sequence ⁶ ^ of the last detected transmit antenna and storing in the first memory The results of the last detection in the middle are not the same, and when the number of iterations does not meet the requirements, ⁶ ^ is taken as the new known interference, and each layer is re-detected according to the order of ->d->...".

The receiver according to claim 17, wherein the ordering and frequency domain equalization unit determines the undetected transmitting antenna having the largest signal to noise interference ratio as the transmitting antenna to be currently detected.

The receiver according to claim 17, further comprising:

And a third data recombiner, configured to perform parallel-to-serial conversion on the final measurement result, and then perform data recombination on the decision value, and then enter the parallel-to-serial converter.