WO2006082924A1

WO2006082924A1 - Multi-antenna communication device

Info

Publication number: WO2006082924A1
Application number: PCT/JP2006/301865
Authority: WO
Inventors: Xiaoming She; Jifeng Li
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-02-04
Filing date: 2006-02-03
Publication date: 2006-08-10
Also published as: CN1815941A

Abstract

An antenna selection/bit distribution control unit (207) is provided for obtaining an antenna selection parameter and an adaptive modulation/encoding parameter according to a channel characteristic matrix estimated by a channel estimation unit (206), feeding back the parameters to the transmission side, and controlling the transmission antenna selection at the transmission side and bit distribution. This enables transmission using only a transmission antenna having a preferable channel characteristic in accordance with the antenna selection parameter and control of the bit distribution (i.e., throughput) by the adaptive modulation/encoding parameter without complicating the system.

Description

Specification

Multi antenna communication device

Technical field

The present invention relates to a multi-antenna communication apparatus, a multi-antenna system, a multi-antenna communication method, and an antenna selection 'bit distribution method used in a Multiple-Input Multiple-Output (MIMO) system.

Background art

[0002] With the convergence of wireless networks and the Internet, the demand for wireless communication services and quality is increasing. Transmission rates are one of the main problems that future wireless communication systems attempt to solve. New wireless communication systems need to be developed to meet the requirements of wireless multimedia and high, rate data transmission. Conventional research mainly focuses on how to communicate using time domain resources and frequency domain resources.

Recently, with the advent of MIMO technology, a new direction has been launched for researchers. In the Ml MO system, the transmitting side transmits signals by a plurality of antennas, and the receiving side receives signals by a plurality of antennas. Research has shown that MIMO technology significantly increases channel capacity compared to conventional single antenna transmission methods. Also, as space resources are almost endlessly available compared to time domain and frequency domain resources, MIMO technology can overcome the bottlenecks of the prior art, making it the core technology of the next generation wireless communication system. It becomes.

[0004] At present, most of the research conducted on multi-antenna communication systems is space division multiplexing and space-time coding. In space division multiplexing, the system transmission rate is increased by transmitting different codes by each antenna, and in space-time codes, system bits are inserted by inserting code redundancy between transmission signals of different antennas. Increase the error rate. Recently, MIMO-OFD M technology combining MIMO and OFDM has attracted attention.

FIG. 1 is a diagram showing the configuration of a conventional MIMO system. This MIMO system is SZ A P (serial Z parallel) conversion unit 101, a plurality of code and modulation units 102, a plurality of transmission antennas 103, a plurality of reception antennas 104, a MIMO detection unit 105, and a channel estimation unit 106 are provided. An SZP converter 101, a plurality of code and modulation units 102, and a plurality of transmitting antennas 103 are included on the transmitting side, and a plurality of receiving antennas 104, a MIMO detector 105, and a channel estimation unit 106 are included on the receiving side. Be

According to the configuration shown in FIG. 1, the transmitting side and the receiving side each have n transmitting antennas 10.

T

3 and n receive antennas 104 (where n and n are natural numbers) to transmit and receive signals.

R T R

Do.

On the transmission side, the data waiting for transmission is first processed by the SZP conversion unit 101 to n pieces of data.

T

It is divided into substreams. Each of the divided data substreams corresponds to one antenna 103. The data substreams awaiting transmission are first input to the corresponding encoding and modulation unit 102. The coding / modulation section 102 performs coding and modulation on the input data sub-stream. The encoded and modulated data are sent to the corresponding transmit antenna 103 and transmitted from the corresponding transmit antenna 103.

[0008] On the receiving side, first, all the signals in space are received by n receiving antennas 104.

R

And, channel estimation section 106 performs channel estimation based on the pilot signal of the received signal or using another scheme to estimate the current channel characteristic matrix H (for the MIMO system, the channel Properties can be represented by a matrix). Next, based on the matrix H obtained by the MIMO detection unit 105, detection is performed on the signal received by each receiving antenna 104, and the original transmission data is obtained. Various methods can be used in MIMO detection. For example, habitual ZF (zero forcing), MMSE (least root mean square error), serial interference cancellation or other methods are often used.

Usually, MIMO detection section 105 includes an operation of separating the signal transmitted by each transmission antenna on the transmission side, and an operation of performing demodulation and decoding on each signal. Note that in actual MIMO detection, these two operations are not performed independently in most cases. That is, the output from the former is obtained by the latter, and the output of the latter is often required for the progress of the former. For this reason, it is generally Described in the output section 105.

[0010] A MIMO configuration as shown in FIG. 1 is generally called a V-BLAST (Vertical Bell Laboratories Layered Space-Time) system. In an actual MIMO system, changes can be made. By converting the correspondence between each transmission data substream and each transmission antenna, it is possible to obtain a MIMO system of another configuration, such as a D-BLAST (Diagonal Bell Laboratories Layered Space-Time) system, for example. In addition, on the transmission side, after the adaptive modulation Z code input unit, an SZP conversion unit, an IFFT (Inverse Fast Fourier Transform) unit, a PZS conversion unit, a CP (Cyclic Prefix) addition unit, etc. are added, and a MIMO-OFDM system is added. It is an important thing to do.

Disclosure of the invention

Problem that invention tries to solve

However, in the conventional MIMO system, transmission antenna selection is usually not performed, and all antennas transmit signals. Thus, due to channel fading, the characteristics of the channels to which each transmit antenna of the MIMO system corresponds may differ, and in fact, the characteristics of a channel to which a certain transmit antenna corresponds may be very bad.

Generally, in a MIMO system, the overall throughput is increased by an increase in the number of transmit antennas. As described above, if there is an antenna with a very poor channel characteristic, the overall throughput will be increased. In some cases, only power consumption can not be increased.

[0013] Also, if the number of transmitting antennas is simply changed, the throughput of the entire system also fluctuates accordingly, and as a result, the entire system may be complicated.

The object of the present invention is to construct a system in which channel characteristics are sufficiently taken into consideration, thereby enabling efficient multi-antenna transmission using transmission antennas efficiently, and complicating the entire system configuration. What is needed is to provide a multi-antenna communication device, a multi-antenna transmission system, and a multi-antenna communication method.

Means to solve the problem

[0015] The multi-antenna communication apparatus of the present invention is configured to transmit a current channel based on a received signal. Based on the channel estimation means for estimating the characteristic matrix and the estimated channel characteristic matrix, the antenna selection parameter and the adaptive modulation 'code parameter are obtained, these parameters are fed back to the transmitting side, and the transmitting side is obtained. Antenna selection 'bit distribution control means for controlling transmission antenna selection and bit distribution of the channel, current channel characteristic matrix obtained by the channel estimation means, the fed back antenna selection parameter and adaptive modulation' coding parameter And a MIMO detection unit for detecting each transmission data substream and obtaining the original transmission data.

[0016] According to this configuration, the antenna selection parameter and the adaptive modulation 'coding parameter are obtained by the antenna selection' bit distribution control means based on the channel characteristic matrix, and these parameters are fed back to the transmission side. As a result, it is possible to perform transmission using only the transmitting antenna and to perform channel distribution (that is, throughput) complicated by the adaptive modulation 'coding parameter. You will be able to control it as you like.

Effect of the invention

According to the present invention, the transmitting antenna is selected based on the channel characteristic matrix on the receiving side, and bit distribution to each selected transmitting antenna is determined by the modulation multi-level number and / or coding rate of adaptive modulation. Therefore, the transmission antenna can be efficiently used to perform high-efficiency data transmission, and bit distribution can be performed with a simple configuration when performing high-efficiency multi-antenna transmission. .

In other words, according to the present invention, it is possible to effectively improve the error rate performance of the MIMO transmission system which does not complicate the system, as compared with the prior art.

Brief description of the drawings

FIG. 1 is a diagram showing the configuration of a prior art MIMO radio system.

[FIG. 2] A diagram showing the configuration of a multi-antenna communication system according to an embodiment of the present invention [FIG. 3] A flow diagram of the entire system executing the multi-antenna communication method according to an embodiment of the present invention

[FIG. 4] Antenna selection in multi-antenna communication system according to an embodiment of the present invention 'flow chart for explaining a bit distribution method [FIG. 5] A figure showing a comparison of performance in the method used in the present invention and the conventional method when the number of transmitting Z receiving antennas is four in all.

[FIG. 6] A diagram showing a comparison of performance between the method used in the present invention and the conventional method when the number of transmitting Z receiving antennas is both 2.

BEST MODE FOR CARRYING OUT THE INVENTION

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

FIG. 2 is a diagram showing the configuration of a multi-antenna communication system for controlling antenna selection and bit distribution according to an embodiment of the present invention. In practice, the multi-antenna communication system comprises a first multi-antenna communication device having a transmitting system and a receiving system, and a second multi-antenna communication device having a transmitting system and a receiving system. The present embodiment is mainly characterized in the transmission system of the first multi-antenna communication apparatus and the reception system of the second multi-antenna communication apparatus, and therefore, only that portion is shown in FIG. In the following description, the first multi-antenna communication apparatus is referred to as the transmitting side, and the second multi-antenna communication apparatus is referred to as the receiving side.

The transmitting side includes a plurality of transmitting antennas 204, a plurality of encoding / demodulation units 203 provided corresponding to each antenna 204, an SZP conversion unit 201 for serial-to-parallel conversion of transmission data, and an SZP conversion unit. It has a plurality of transmission antenna selection units 202 which are provided between the conversion unit 201 and the plurality of coding / modulation units 203 and which are a plurality of switchers.

The reception side includes a plurality of reception antennas 205, a MIMO detection unit 209, a channel estimation unit 206, and an antenna selection 'bit distribution control unit 207. The channel estimation unit 206 and the antenna selection 'bit distribution unit 207 are connected to the MIMO detection unit 209.

Next, the operation of the MIMO system according to the embodiment of the present invention will be described using FIG. In the configuration of FIG. 2, the transmit side and receive side of the MIMO system are each n

T

With n transmit antennas 204 and n receive antennas 205 (where n and n are natural numbers)

R T R

Send and receive signals.

On the transmission side, the data waiting for transmission is first processed by the SZP conversion unit 201 to n pieces of data.

T

It is divided into substreams. Each of n divided data substreams is one

T

Corresponding to the transmitting antenna 204 of The transmission antenna selection unit 202 selects transmission antennas that actually transmit from all the transmission antennas 204. Then, the adaptive modulation ′ coding unit 203 performs adaptive modulation ′ code on the data substream selected by the transmission antenna selection unit 202. The adaptive modulation 'coded data substream is transmitted by the corresponding transmission antenna.

[0027] Control parameters C 1, C 2,---, C (where C represents the selection status of transmission antenna k, k = 1 ,,) are required when transmission antenna selection section 202 performs transmission antenna selection. 2, ...,! 1, C is binary

1 2 nT k T k mod number whose values “1” and “0” respectively indicate two situations not selected when the transmitting antenna k is selected), and the adaptive modulation 'coding unit 203 selects In performing adaptive modulation and coding on the data substreams, the required parameter M (the parameter M indicates the number of data bits currently transmitted from each transmitting antenna, and in this embodiment, Adaptive modulation on the transmitting side at the same time · The coding unit 203 uses the same parameter M) is obtained by channel estimation on the receiving side. That is, the receiver feeds back the acquired parameters to the transmitter via the feedback channel 208.

[0028] On the receiving side, first, n receiving antennas 205 receive all the signals in space.

R

Be

Then, channel estimation section 206 performs channel estimation using, for example, a method using pilot signals in the received signal or other methods to obtain current channel characteristic matrix H.

[0030] Antenna selection 'bit distribution control section 207 obtains antenna selection parameter C and adaptive modulation' coding parameter M according to the method of the present invention (described in detail later) based on matrix H and feeds it back. By feeding back to the transmission side via the channel 208, antenna selection 'bit distribution control on the transmission side is performed.

[0031] Next, based on channel characteristic matrix H and parameters C and M obtained by antenna selection 'bit distribution section 207, MIMO detection section 209 applies a general MIMO detection method to a data substream. MIMO detection is performed to obtain the original transmission data. Specifically, MIMO detection section 209 separates a plurality of transmission data sub-streams mixed on the propagation path using channel characteristic matrix H, and separates a plurality of separated transmission data sub-streams. The original transmission data is obtained by performing demodulation processing and decoding processing according to the parameters C and M on the memory.

Compared to the conventional MIMO system shown in FIG. 1, there are the following two differences from the multi-antenna communication system of the present embodiment.

(1) As shown in FIG. 1, in the conventional MIMO system, data is transmitted using all of the transmit antennas at all times, whereas in this embodiment, all of the transmission times are used. , Select only the appropriate transmit antenna and transmit based on the current channel characteristics. In the present embodiment, the antenna selection 'bit distribution control section 207 obtains parameters C 1, C 2,---, C by the method proposed in the present embodiment based on the current channel characteristic matrix H. , Send it through feedback channel 208

1 2 nT

Give feedback to

(2) Antenna selection 'bit distribution control section 207 selects adaptive modulation' coding parameters so that the total data throughput from all transmitting antennas is equal before and after changing the number of antennas. . This can prevent the throughput performance of the system from being impaired due to antenna selection (for example, when the number of transmitting antennas is reduced). For example, if, at a given time, antenna selection results in transmitting data by half of the transmission antennas, transmission bits distributed to the selected transmission antennas so as not to cause a loss in the transmission rate of the system. Designate the modulation multi-value number and coding rate by which the number is doubled by the adaptive modulation 'coding norm. Furthermore, in the present embodiment, each adaptive modulation and coding unit 203 on the transmission side at the same time use the same modulation and coding parameters. That is, the number of transmission bits distributed to the selected transmission antenna 204 is the same. As a result, only one adaptive modulation and coding parameter needs to be fed back to the plurality of adaptive modulation and coding units 203, so that the complexity for realizing the system can be achieved while effectively suppressing the parameter feedback overhead. It can be lowered. Also, on the receiving side that has received the transmitted signal subjected to adaptive modulation and coding processing that has been subjected to adaptive modulation and coding parameters that have been fed back, the adaptive modulation 'coding parameter that is fed back in MIMO detection section 209 By performing adaptive demodulation and decoding corresponding to, adaptive modulation 'data before coding is obtained. FIG. 3 is a flowchart of the entire system that executes the multi-antenna communication method of the present embodiment.

First, in step S301, channel estimation is performed by the channel estimation unit 206 on the receiving side based on the received signal, and the current channel characteristic matrix H is obtained. In channel estimation, a general channel estimation method applied to the MIMO system, for example, a pilot based channel estimation method is used. The current channel characteristic matrix H obtained by channel estimation is provided to the antenna selection and bit distribution control unit 207.

Then, in step S302, based on the channel characteristic matrix H obtained by the antenna selection 'bit distribution control unit 207, the antenna selection parameter C and the adaptive modulation' coding parameter M are obtained, and the antenna on the receiving side Selection and bit distribution control is performed (details of this process will be described later).

Thereafter, in step S 303, the antenna selection parameter C and the adaptive modulation and coding parameter M are controlled by the antenna selection and bit distribution unit 207 through the feedback channel 208 to actually control data transmission on the transmission side. Feedback to the sender.

[0039] Next, in step S311, based on the antenna selection parameter C and the adaptive modulation 'coding parameter M in which the receiving side power is also fed back on the transmitting side, antenna selection and adaptive modulation and coding for transmission data are performed. The selected transmit antenna 204 transmits the signal to the receiver side as well as the appropriate transmit antenna 204 is selected.

Then, in step S 304, MIMO detection is performed on the received signal by the MIMO detection unit 209 on the receiving side, and the original transmission data is obtained.

[0041] FIG. 4 is a flowchart showing a method of controlling antenna selection 'bit distribution in the multi-antenna communication system of the present embodiment, that is, a detailed method for realizing step S302 of FIG. The antenna selection 'bit distribution control method proposed in the present embodiment will be described in detail with reference to FIG.

The antenna selection 'bit distribution control method of the present embodiment is a recursion process. Specifically, first, in step S401, initialization is performed. The transmit antenna set S includes all transmit antennas, ie, S = {l, 2 to n}, where n is the number of transmit antennas.

T T

The total throughput of the system is R_total bit / s / Hz, and each transmission included in S The amount of throughput distributed to the antennas is R = R_total / length (S), where length (S) is the length of the set S, ie the number of transmit antennas included in S.

Here, the adaptive modulation ′ coding parameter on the transmission side can be represented by the number R of transmission data bits averaged. In actual data transmission, an appropriate modulation 'coding parameter is selected based on the transmitter's own numerical value. In actual operation, adaptive transmission can be realized by fixing modulation parameters and changing coding parameters based on the value of R. For example, the modulation scheme is fixed to 64 QAM, a turbo code of coding rate 1Z3 is selected in the case of R = 2, and a turbo code of coding rate 1Z2 is selected in the case of R = 3.

Then, in step S 302, the channel characteristic is the worst from the set of transmitting antennas S, and the transmitting antenna is selected and marked as transmitting antenna j. Here, there are two ways to identify the transmitting antenna with the worst channel characteristics as follows.

(1) By comparing the vector reference value (norm) of each column in the channel characteristic matrix H, the reference value of the column vector is the lowest, and the channel characteristic corresponding to the transmitting antenna is the worst. Ru.

The channel characteristics of a MIMO system can be represented by an n × n matrix H, and the matrix factor H

R T

i, j) show the channel characteristics of the spatial path transmitted from the j-th transmit antenna to the i-th transmit antenna. Therefore, the column vectors 1, 2 to n in the matrix H are respectively

T

It corresponds to the channel characteristics of Tena 1, 2 to n. Reference value of each column vector in matrix H

T

The root value of the sum of squares of each factor in the turtle is calculated and compared, and the channel characteristic of the transmitting antenna to which the lowest reference value corresponds is considered to be the worst. Specifically, method (1) is realized by the following steps.

(A) Calculate the reference value of each column 1, 2, ... in the matrix H, and let norm (l), norm (2), · · ·, nor

τ

Get m (n). The equation for calculating the k-th reference value of the matrix H is shown by the following equation.

T

[Equation 1] norm (k) =

(B) The transmit antennas of the transmit antenna set S are compared with the reference values of the columns in the matrix H corresponding to each other, and the transmit antenna corresponding to the matrix with the lowest reference value is taken as the reference antenna j. The channel characteristic to which the transmitting antenna corresponds is considered to be the worst, and is expressed by the following equation.

[Number 2]

/ · = Are inormCk)}

kes

Here, transmission antennas not included in the transmission antenna set S are excluded from comparison.

(2) Calculate the SINR value after detection corresponding to each transmit antenna after MIMO detection, and after detection

The SINR value is the lowest, and the channel characteristics to which the transmitting antenna corresponds are considered the worst.

Here, various methods can be used as the MIMO detection method, and there are, for example, ordinary least mean square error method (MMSE), serial interference cancellation method (SIC), and the like. Specifically, method (2) is realized by the following steps.

(A) The transmit antenna set S calculates the post-detection SINR value corresponding to each transmit antenna, and the post-detection SINR value differs depending on the MIMO detection method actually used, and in many references, Formulas are given. For example, in ZF detection, the SINR value after detection of the signal transmitted from the k-th transmit antenna is expressed by the following equation.

[Number 3]

SINR, ~ r where E _s and No denote the signal and noise power respectively, H denotes the row vector in the matrix 対応 corresponding to the transmit antennas included in the transmit antenna set S (ie H denotes the matrix Η For each column of, if the corresponding transmit antenna is not included in S, we can obtain by making the column in matrix 「'0').

In the MMSE detection, the SINR value of the signal transmitted from the k-th transmit antenna after detection is given by the following equation, and I is an n-dimensional unit matrix.

[Number 4]

(B) The post-detection SINR values corresponding to the respective transmit antennas of the transmit antenna set S are compared with one another, and the transmit antenna with the lowest post-detection SINR value is taken as a reference antenna j. The channel characteristic corresponding to the tena is regarded as the worst, and is expressed by the following equation.

[Number 5]

J = argmin {SINR ()}

Then, in step S403, the transmitting antenna j is removed from the current transmitting antenna set S, and a transmitting antenna set S ′ = S ¥ {j} is obtained. All transmit data bits are distributed equally to the remaining transmit antennas, ie, all transmit antennas of transmit antenna set S ′. At this time, the number of transmission data bits corresponding to each of the transmitting antennas of the transmitting antenna set S ′ is R, = R_total / length (S,).

[0055] Thereafter, in step S404, the bit error rate performances of the receiving side before and after the transmission antenna j is removed are compared. That is, the transmission antenna set S is used, and the throughput amount corresponding to each of the transmission antennas is performance when R = R_totalZlength (S) and the transmission antenna set S ′ is used, and the throughput amount corresponding to each of the transmission antennas is The performance is compared if R '= R_totalZlength (S'). For simplicity, used transmit antenna set S, the throughput quantity corresponding respectively transmit antennas and _{R = R _tot a l / l} e ngth If the case of the (S) A, the transmission antenna set S 'is The throughput amount that each transmit antenna corresponds to is used is R '

Let B be a case where (S,) is true.

In step S 404, the bit error rates at case A and case B are compared, that is, whether the comparison result is BER (B) <BER (A) or not! .

[0057] Here, there are two ways to compare the BER performance in case A and case B as shown below.

(1) In the case A, SINR values are calculated after MIMO detection of the signals of the respective transmit antennas, and MIMO detection of the signals of the respective transmit antennas is performed based on the throughput amount distributed to the respective transmit antennas. Then, determine the BER (to obtain the BER value by simulation or logic estimation). In this case, the average value of the corresponding BER values for each transmit antenna is taken as the BER for A, and is denoted here as BER (A). The BER (B) is obtained by the same method, and the BER (A) is compared with the BER (B). Specifically, method (1) is realized by the following steps. (A) In each case A and B, the SINR value is calculated after MIMO detection of each transmit antenna signal, and the kth transmit antenna signal is in the case A and case B after detection SINR value is These are denoted as SINR (k) and SINR (k), respectively, and are the same as step S402 described above.

A B

It is obtained by various calculation methods.

(B) A comparison table of SINR value and BER value is determined by simulation or logical formula. By searching the comparison table, the SINR value can directly find out the corresponding BER value.

(C) By searching the comparison table, BER values after MIMO detection of respective transmit antenna signals in case A and case B are determined. The SINR values after MIMO detection in cases A and B for the kth transmit antenna signal are BER (k) and BER (k (k), respectively.

A B

It is indicated that), where BER (k) = f (SINR (k)), BER (k) = f (SINR (k)), f () is the control

A A B B

It is a tape notch function.

(D) Calculate the average BER value in case A and case B, and calculate BER (A) and BER

Ask for (B).

[Number 6]

Bm (A) =-^ — BER _A (k)

length (S)

[Number 7]

BER (B) —— Y BER k)

(2) In case A, only the BER value corresponding to the transmitting antenna with the lowest SINR after MIMO detection is calculated, which is indicated as BER (A). Obtain BER (B) by the same method, and compare BER (A) with BER (B). Method (2) can significantly reduce the amount of calculation compared to the method described above. Specifically, the method (2) is realized by the following steps.

(A) Calculate SINR value after MIMO detection of the signal of each transmitting antenna in case A and case B respectively, and calculate the SINR value after MIMO detection in case A and B when signal of k-th transmission antenna is The step S4 described specifically as SINR (k) and SINR (k)

A B

It is obtained by the same calculation method as 02. (B) A comparison table of SINR value and BER value is determined by simulation or logical formula. By searching the comparison table, the SINR value can directly find out the corresponding BER value.

(C) Determine the lowest post-detection SINR value in each case A and B, and find SINR (A) and SINR (B) shown by the following equations.

min min

[Number 8]

SINR ^ (A) = arg min {SINR _A (k)}

[Number 9]

SINR ^ iB) = arg {male}

AS

(D) By searching the control table, the determined lowest 前記 SINR value determines the corresponding BER value, ie, BER (A) = f (SINR (A))

min, BER (B) = f (SINR (B))

min, where f 0 is a comparison table function.

In step S 404, if it is determined that BER (B) <BER (A), and the number of transmission antennas included in the transmission antenna set S is larger than 1, step S 405 is transferred.

In step S405, the transmitting antenna set S is updated to S ′, that is, S = S ′ and throughput R = R ′. Then, in step S402, the recursion operation is continued.

If it is determined in step S 404 that BER (B) <BER (A) is not satisfied, step S 406 is transferred.

In step S406, the entire process of parameter selection and bit distribution control is ended, and the selected transmit antenna set S, and the amount of throughput R corresponding to all the transmit antennas included in S are obtained. That is, the parameters (S, R) are selected as the final selection result. In other words, antenna selection parameter C and bit distribution parameter M are obtained. It is a binary sequence of 1's and 0's, and '1' and '0' indicate that the transmitting antenna is or is being used, respectively. The value of M is the same as R.

FIG. 5 and FIG. 6 respectively show the comparison of the BER performance of the method used in the present invention and the conventional method. The horizontal axis shows the signal-to-noise ratio (SNR), and the vertical axis shows the bit error rate.

The numbers of transmit antennas and receive antennas shown in FIG. 5 are both 4, ie, n = 4 and n It is a comparison result in the case of = 4. The numbers of transmit antennas and receive antennas shown in FIG. 6 are both 2, that is, the comparison results in the case of n = 2 and n = 2. In simulation,

T R

The total throughput of the system is 8bps ZHz and 12bps ZHz, using a channel fading channel. As can be seen from the results in FIGS. 5 and 6, better BER performance can be obtained by using the method of the present invention as compared to the conventional method.

As described above, according to the present embodiment, the antenna selection parameter and the adaptive modulation 'coding parameter are obtained based on the channel characteristic matrix estimated by channel estimation section 206, and these parameters are calculated. Antenna selection 'Bit distribution control section 207 that feeds back to the transmission side and controls transmission antenna selection and bit distribution on the transmission side By transmitting only the transmission antenna with good channel characteristics according to the antenna selection parameter is provided. The adaptive modulation 'coding parameters allow the system to control the bit distribution (ie throughput) as well as it can.

In the present embodiment, although the case where transmission antenna selection unit 202 is provided on the transmission side has been described as an example, the present invention is not limited to this, transmission antenna selection unit 202 is provided on the reception side, and The back channel may control transmission antenna selection and bit distribution. Alternatively, it may be performed by the antenna selection 'bit distribution control unit 207 on the receiving side.

Further, although the configuration of the multi-antenna communication system as shown in FIG. 2 has been described as an example in the present embodiment, the present invention is not limited to this, and the configuration of FIG. . For example, the correspondence relationship between each transmission data substream and each transmission antenna may be changed. In addition, it is possible to make an M IMO-OFDM system by adding a fast Fourier inverse transform unit, a CP addition unit, and the like.

This specification is based on Chinese Patent Application No. 200510006754.9 filed on February 4, 2005. All the contents are included here.

Industrial applicability

The multi-antenna communication apparatus of the present invention is applicable to a multi-antenna communication system or the like that performs transmission in a fluctuating channel environment.

Claims

The scope of the claims

[1] Channel estimation means for estimating the current channel characteristic matrix based on the received signal,

Based on the estimated channel characteristic matrix, the antenna selection parameter and the adaptive modulation 'coding parameter acquisition are obtained, and these parameters are fed back to the transmitting side to select the transmitting antenna selection and bit distribution control. Detection for each transmitted data substream is based on bit distribution control means, the current channel characteristic matrix obtained by the channel estimation means, the fed-back antenna selection parameter and the adaptive modulation 'code parameter. , MIMO detection means for obtaining the original transmission data,

A multi-antenna communication device comprising

[2] The antenna selection 'bit distribution control means selects the adaptive modulation / coding parameter so that total data strength of all transmitting antenna powers becomes equal before and after changing the number of antennas.

The multi-antenna communication device according to claim 1.

[3] The MIMO detection means may adaptively demodulate / decode each transmitted data substream based on the antenna selection parameter and the antenna modulation parameter provided and the adaptive modulation 'code parameter'. Perform

The multi-antenna communication device according to claim 1.

[4] The antenna selection and bit distribution control means may reduce the number of transmit antennas in order from the antenna until the effect of improving the BER of the transmit data obtained by the MIMO detection means disappears. Feed back the antenna selection parameters shown to the transmitter,

The multi-antenna communication device according to claim 1.

[5] The channel estimation means estimates channel characteristics each time the number of transmission antennas decreases.

The antenna selection and bit distribution control means identifies an antenna with the worst channel characteristic every time the number of transmitting antennas is reduced.

The multi-antenna communication device according to claim 4

[6] A multi-antenna communication system comprising: a first multi-antenna communication device; and a second multi-antenna communication device capable of communicating with the first multi-antenna communication device, wherein the first multi-antenna communication device Is

Channel estimation means for estimating a current channel characteristic matrix based on the signal received from the second multi-antenna communication device;

Based on the channel characteristic matrix estimated by the channel estimation means, an antenna selection parameter and an adaptive modulation 'code parameter are obtained, and these parameters are fed back to the second multi-antenna communication apparatus, Antenna selection 'bit distribution control means for controlling transmission antenna selection and bit distribution of the second multi-antenna communication apparatus, channel characteristic matrix estimated by the channel estimation means, and antenna selection' bit distribution control means MIM 0 detection means for detecting each transmission data substream based on different antenna selection parameters and adaptive modulation and coding parameters to obtain original transmission data;

Equipped with

The second multi-antenna communication device is

Antenna selection means for selecting data of at least one transmitting antenna and selecting at least one transmitting antenna based on the antenna selecting parameter fed back also to the first multi-antenna communication device power;

A plurality of adaptations that perform adaptive modulation and coding based on the adaptive modulation and coding parameters that are also fed back to the first multi-antenna communication device power for the data stream selected by the antenna selection device. Modulation · encoding means,

Equipped with

Multi-antenna communication system.

[7] The antenna selection 'bit distribution control means selects the adaptive modulation / coding parameter so that total data strength of all transmission antenna powers become equal before and after changing the number of antennas.

The multi-antenna communication system according to claim 6.

[8] The plurality of adaptive modulation 'coding means perform adaptive modulation' coding using the same adaptive modulation 'coding parameter in which the first multi-antenna communication device power is also fed back, respectively.

The multi-antenna communication system according to claim 6.

[9] A channel estimation step of estimating the current channel characteristic matrix based on the received signal,

Based on the estimated channel characteristic matrix! Thus, antenna selection and bit distribution control steps for controlling transmission antenna selection and bit distribution on the transmission side by obtaining antenna selection parameters and adaptive modulation and coding parameters and feeding back these parameters on the transmission side, and ,

Detecting each transmitted data substream based on the current channel characteristic matrix and the fed back antenna selection parameter and adaptive modulation 'coding parameter to obtain the original transmitted data;

Multi-antenna communication method including:

[10] Based on the estimated channel characteristics, identify the transmitting antenna with the worst transmission channel characteristic of the current transmitting antenna, and obtain an antenna selection parameter indicating the remaining transmitting antennas from which the specified transmitting antenna has been removed. a,

Obtaining an adaptive modulation 'coding metric that averages out transmit data bits to the remaining transmit antennas; b.

The antenna selection parameter and the adaptive modulation · coding parameter are fed back to the transmission side, and the transmission side is made to select a transmission antenna according to the antenna selection parameter and a bit according to the adaptive modulation 'code parameter Step c of causing the distribution

Comparing the bit error rate (BER) performance of the receiver before and after the transmit antenna with the worst channel characteristic is removed, and d.

Including

If the channel characteristics are the worst and the bit error rate performance after removing the transmitting antenna is better than the bit error rate performance before removing, repeat steps a to d, If the channel characteristics are the worst and the bit error rate performance after removing the transmit antenna is not better than the bit error rate performance before removing, then transmit the data bits with the current transmit antenna,

Antenna selection and bit distribution method in a multi-antenna communication system.

[11] The step a is

The step of calculating the reference value of each column vector in the estimated channel characteristic matrix and the calculated reference value are compared with each other, and the reference value is the smallest! The channel characteristic of the transmitting antenna is the worst! And the step of identifying

The method of antenna selection and bit distribution in a multi-antenna communication system according to claim 10, comprising:

[12] The step a is

Calculating the signal interference ratio of each transmit antenna;

Comparing the calculated signal interference ratios with one another to identify the signal interference ratio as the smallest and the channel characteristics of the transmitting antenna as the worst.

[13] Step d is

The channel characteristics are the worst, the signal interference ratio before removing the transmitting antenna, and the signal characteristics after the removal of the transmitting antenna is the worst, and these signal interference ratios and each transmitting antenna are calculated. Estimate the bit error rate after MIMO detection based on the throughput amount distributed to

A method of antenna selection and bit distribution in a multi-antenna communication system according to claim 10.

[14] In step d, using a comparison table in which the signal interference ratio is associated with the bit error rate, the comparison table is searched to obtain a bit error rate value corresponding to the calculated signal interference ratio.

A method of antenna selection and bit distribution in a multi-antenna communication system according to claim 10. In step d, the channel characteristic is the worst, the signal interference ratio before removing the transmitting antenna is the smallest, the bit error rate value of the transmitting antenna and the channel characteristic are the worst, and the signal interference after removing the transmitting antenna Calculate the bit error rate value of the transmitting antenna, and compare the bit error rates of the two with each other.