WO2010000095A1

WO2010000095A1 - Method for executing open loop space multiplexing by pre-coding de-correlation

Info

Publication number: WO2010000095A1
Application number: PCT/CN2008/001257
Authority: WO
Inventors: 汪勇刚
Original assignee: 上海贝尔阿尔卡特股份有限公司; 阿尔卡特朗讯
Priority date: 2008-07-01
Filing date: 2008-07-01
Publication date: 2010-01-07
Also published as: CN102067475B; CN102067475A

Abstract

This invention provides a method for executing open loop space multiplexing by pre-coding de-correlation. H is a channel transmission matrix of a MIMO (multiple input multiple output) system, and the value of matrix det(H^/H) is made to be maximal to permit realizing the maximal capability of an open loop space multiplexing system. The signal strength of each layer of the MIMO system is made to be equal and orthogonal to each other, that is, the channel transmission matrix of MIMO is an orthogonal and diagonal matrix. In pre-coding MIMO, the equivalent MIMO channel corresponding to a specific pre-coding matrix E can be rebuilt by applying H_E=HE. The pre-coding technology can reduce the influence of channel correlation in space multiplexing system to the most degree, and the UE(user equipment) can use de-multiplexing very well and detect signal, and this largely improves the transmission quality of E-MBMS service. In addition, no any additional complexity is imported, and the method is applicable to open loop MIMO in MBSFN.

Description

Method for performing open-loop spatial multiplexing by using precoding de-correlation

The present invention relates to the field of MIM0, and in particular to a method for performing open-loop spatial multiplexing using precoding de-correlation. Background technique

Single Frequency Network (SFN) operation can be used for broadcast/multicast communication using OFDM transmission from multiple cells with timing errors over the periodic prefix length. When there is SFN operation, the broadcast SINR can be very high for smaller cell configurations.

What is expected is that the LTE system will employ some form of MIM0 technology for unicast communication. ^f When multiple transmit and receive antennas and multiple transmit and receive chains are available, it is also true for E-MBMS; the benefits of using MIM0 are logical. However, the key difference between unicast and broadcast is that only "open loop" MIM0 technology can be used for E-MBMS. This includes some form of transmit diversity or "open loop" spatial multiplexing of multiple streams.

But for open-loop spatial multiplexing, it has strict limits on multicast in the relevant channel. When the UE is very close to an eNB, the power received from the base station is much stronger than the power received from other base stations. In addition, both transmit antennas of the eNB have a direct path to the UE receiver antenna, which is a typical Rician or Line of Sight (L0S) channel. In this case, the channel response vector is strongly correlated. Because it is open-loop spatial multiplexing, quadrature compensation from the transmitter cannot be obtained based on the feedback information. As a result, the UE can no longer demultiplex the two symbols.

There are several options for improving the performance of L0S users. The first solution is the simplest; the scheme emits different streams at different polarizations. Therefore, the UE receiving antenna of the double polarized: will be able to easily separate the two streams and decode the transmitted data. On the other hand, the performance of L0S users can also be improved with advanced receivers (匪 SE-SIC or MLD).

However, because dual polarization does not provide diversity gain, dual-polarized antennas cannot be applied to transmit diversity in unicast, such as STBC or SFBC. When it is in unicast and MBMS mixed carrier mode, or the UE receives both unicast and MBMS services, the eNB and UE antenna configuration will be time-frequency ^S complex, the configuration leads to an increase in complexity. On the other hand, advanced receivers are still under study, and their performance and complexity are being tested. Summary of the invention

It is an object of the present invention to provide a precoding method for an open loop spatial multiplexing system for reducing correlation between channels to improve L0S user performance.

According to an embodiment of the present invention, a channel precoding method is proposed, which is applied to a ring-and-loop spatial multiplexing system of a MIM0 system, where H is a channel transmission matrix of a MIM0 system, and the channel precoding method performs a signal on an input channel. Precoding, which maximizes the det (H'H) of the channel transmission matrix, thereby allowing the chirp space multiplexing system to achieve maximum capacity.

Preferably, the precoding makes the signal strengths of the layers of the MIM0 system equal and positive:, that is, the channel transmission matrix M of the MIM0 is an orthogonal diagonal matrix.

Preferably, in the precoding MIM0, the equivalent IM0 channel corresponding to the specific precoding matrix E can be reconstructed by applying Η _Ε = 。.

Preferably, for the Μ * M MIM0 system, the channel transmission matrix is precoded using cyclic delay diversity CDD precoding.

Preferably, for the MIM0 channel transmission matrix of rank=2, the equivalent MIM0 channel corresponding to the specific precoding matrix is H = H _W R^E , the precoding matrix

Preferably, for a 2*2MIM0 system, the equivalent MIM0 channel is H = H _W R "C

Said

.Precoding matrix φΐί = π

Preferably, the Μ*Μ MIMO system, the equivalent MIM0 corresponding to the specific precoding matrix E

: The channel transmission matrix is a diagonal matrix.

Preferably, for a 2*2 MIM0 system, an equivalent MIM0 corresponding to a particular precoding matrix E

1 X

E =

- λ

If ii3⁄4 H = H _w R^ ² E = H _w I .

Preferably, wherein = 0. ³³³ . Preferably, for the M*M MIM0 system, the equivalent MIMO; channel transmission matrix corresponding to the specific precoding matrix E is a lower triangular matrix.

H 1

Channel is

Preferably, the precoding matrix D has the following form:

Preferably, 1 = 0.627 and = .

According to another embodiment of the present invention, a channel precoding apparatus is proposed, which is applied to a ring-and-loop spatial multiplexing system of a MIM0 system, where H is a channel transmission matrix of a MIM0 system, and the channel precoding apparatus is for an input channel The signal is precoded to maximize the det(H'H) of the channel transmission matrix, thereby allowing the chirp space multiplexing system to achieve maximum capacity.

Preferably, the precoding apparatus makes the signal strengths of the layers of the MIM0 system equal and orthogonal to each other, that is, the channel transmission matrix H of the MIM0 is an orthogonal diagonal matrix.

Preferably, in the precoding MIM0 system, the equivalent MIM0 channel corresponding to the specific precoding matrix E can be reconstructed by applying H _E =HE.

Preferably, for the M*M MIM0 system, the channel transmission matrix is precoded using a CDD precoding scheme.

Preferably, for the MIM0 channel transmission matrix of rank=2, the equivalent MIM0 channel corresponding to the specific precoding matrix is H = H _w RE , the precoding matrix

Preferably, for a 2*2MIM0 system, the equivalent MIM0 channel is H = H. „R. C

Said

1

C = 1 1

Precoding matrix Ε , where ^ (f>k = π Preferably, for M*M MIMO systems, the equivalent MIM0 channel transmission matrix corresponding to a particular precoding matrix E is a diagonal matrix.

Preferably, for a 2*2 MIM0 system, an equivalent MIM0 corresponding to a particular precoding matrix E Channel is Η

Preferably, wherein A = 0.333.

Preferably, for the M*M MIM0 system, the equivalent MIMO channel transmission matrix corresponding to the specific precoding matrix E is a lower triangular matrix.

Ι - λ

Preferably, wherein the precoding matrix D has the following form:

Ground, A = 0.627 and = I.

The technical solution according to an embodiment of the present invention has the following beneficial effects: Precoding can minimize the influence of channel correlation in a spatial multiplexing system, and the UE can use demultiplexing and detect signals very well, which greatly improves E. - MBMS service transmission quality, without introducing any additional complexity; for open-loop MIM0 in MBSFN. DRAWINGS

The advantages of the present invention will become readily apparent from the following description in conjunction with the accompanying drawings in which Figure 1 illustrates a pre-coded MIM0 channel;

1 1

Figure 2a shows the use of precoding matrix I 1 - 1

The decorrelation effect, ie = 0 in method 1. Figure 2b shows the corresponding ratio of the two layers of signal strength, ie p in method 1, and Figure 3a shows the use of precoding matrix

P, φΐ^ φ ',

Figure 3b shows the corresponding ratio of the two layers of signal strength, ie ρ in method 1, and Figure 4a shows the use of precoding matrix

That is, P in the method 2, λ = 0.627.

Figure 4b shows the corresponding ratio of the two layers of signal strength, ρ, λ in Method 2. Figure 5a shows the use of precoding matrix 0.949 1 - 0.333

The decorrelation effect of 0.333 1 , that is, in method 2, 2 = 0.333 ;

Figure 5b shows the corresponding ratio of the two layers of signal strength, ie p in the method 2, A = 0.333;

0.373 - 0.629

0.937 ·

Figure 6a shows the use of precoding matrix 0.373 1

The de-correlation effect, ie, P in method 3, A = 0.627;

Figure 6b shows the corresponding ratio of the two layers of signal strength, ie p, λ = 0.627 in method 3; Figure 7a shows the use of precoding matrix

Fruit, ie P in the method 3, = 1.414;

Figure 7b shows the corresponding ratio of the two layers of signal strength, ie p, = 1.414 in method 3; Figure 8 shows the performance of method 2 in the link level simulation, where

E λ = 0.333;

Figure 9 shows a BLER curve received by the UE;

Figure 10 shows the corresponding CDF of the correlation;

Figure 11 shows the BLER curve received by the UE, wherein Figure 11a shows the result of the UE moving within a 300m radius of the cell, and Figure ib shows the result of the UE moving within a 100m radius of the cell;

Figure 12 again shows the corresponding CDF of the correlation.

A detailed reference is now provided to embodiments of the invention. The following examples will be described with reference to the accompanying drawings in order to explain the invention.

It is well known that E-MBMS performance is typically determined by the "outage" probability requirements of the cell edge user. However, cell edge users can receive E-MBMS signals from multiple cells. For single-frequency network (SFN) operation, the SINR for a cell edge user may be relatively high, for example, for most common cell sizes 10. OdB or more. These higher SINRs for cell edge users can be converted to higher data rates and capacities for E-MBMS by MIM0 spatial multiplexing. Note: If there is no spatial multiplexing, the multicast/broadcast capacity will increase logarithmically with the SINR in the high SINR region.

It has been pointed out that open-loop transmit diversity has almost no diversity gain for broadcasts utilizing SFN operations. However, for the spatial multiplexing of the ring, there are strict restrictions on the multicast of the coherent channel, such as L0S. In an embodiment of the present invention, an open loop precoding method is proposed for resisting channel correlation when a UE is in the vicinity of an eNB for broadcast spatial multiplexing.

The precoding method according to an embodiment of the present invention is generally described below by taking a 2*2 transmission channel matrix as an example. Channel matrix

Defined two transmitters, two receivers

[2Tx, 2Rx] system, there is

It allows open-loop spatial multiplexing to achieve maximum capacity of this type of system with a channel matrix is to maximize det ^ ⁷ ^ channel matrix. If the received signal strength is given as a constant, ie l ^A ' ^{l|2 +|/l} ' ^{2|2 + 2 +|/1⁄2|2 =e} , the condition can be transformed into the following relationship:

Ι Γ+|Α ₂₁ Γ =Ι^Γ+Ι^ ₂ Γ (i)

Equation (1) indicates that the two layers have equal signal strength, and equation (2) indicates that the channel vectors of the two layers are orthogonal to each other.

When measuring the robustness of the channel, it is necessary to normalize it with certain properties. During the study of the present invention, ^ + l ^ l ^{2 is} used to represent the ratio of the signal intensities of the two layers, and And use

It should be understood that the 2*2 MIM0 transport channel is the simplest MIM0 system. For the sake of simplicity, the following parts of the present invention are described by way of example only with a 2*2 MIM0 transmission system. However, it should be understood by those skilled in the art that the method described in the following embodiments of the present invention is also applicable to a MIM0 system of more than two units, and only needs to be applied to the number of units of the MIM0 system according to the principles of the present invention. Precoding matrix. Method 1 according to the first embodiment of the present invention

As shown in Figure 1, in precoding MIM0, the input symbols are obtained by Ε unique transformation. The equivalent MIM0 channel corresponding to a particular precoding matrix 可以 can be reconstructed by applying =ΗΕ. Each UE knows the precoding method and demodulates the precoded stream based on the HE.

In general, the codebook precoded in rank=2, 2*2 SU-MIM0 is [3GPP 36.211].

Without loss of generality, first use E. Analyze.

By using correlations that are parameterized by the transmit and receive parameters ^p ' and ^

The Kronecker MIM0 model simplifies analysis. The channel matrix is given by the following equation: H = R' _R . H _W R ' ² ( ₃ ) where _{R A} is the reception correlation matrix and R _T is the emission correlation matrix under the assumption that the matrix and R _T are independent of the transmitting and receiving elements, respectively. For the [2Tx, 2Rx] system, the R _R and R _T matrices have the following form:

Hw is a spatial white matrix. The elements of Hw can be modeled as zero-mean circularly symmetric complex Gaussian random. That is, Hw is independent of antenna correlation.

To simplify the analysis, the channel model applied in the present invention is that the two transmit antennas from a given Node B are fully correlated and the UE is received on two unrelated receive antennas (as is typical in SCM). Then, the channel matrix is H - H _W R! ² . With a specific precoding moment The equivalent MIM0 channel corresponding to the array is H = HJ. E Let ^ : ^A is the channel coefficient of the two layers before precoding, and ― °—7JLi -iJ . After precoding, the correlation between the channel coefficients and the signal strength ratios of the two layers can be derived as follows:

P pre-coded - 0, P pre-coded = P · , ~ ( 5 )

1 - ? Because although the channel vectors of the two layers are orthogonal to each other, the two layers have completely different signal strengths, so the result is not so good. For example, if Ρ ^{= ()} · ⁸⁶ , Ρ ρ — = ^ι , this means that the imbalance of the two layers can be up to l ldB.

Therefore, other precoding schemes, CDD: Cyclic Delay Diversity precoding, can be tried. It is assumed that the frequency domain CDD is used. In this case, the composite precoder combines Fourier-based precoding and phase shift based CDD delay, as described below.

The equivalent MIM0 channel is

Then, the correlation between the channel coefficients and the signal strength ratios of the two layers can be derived as follows:

= ps\n<f>kl + 7cos ^ It can be found that: Codebook precoding is a specific case of ^=Q or ^{= /2} in CDD precoding.

Ppre -coded

Corpse (g)

Compatible with ^p p - and ideally allows the system to achieve its maximum demultiplexing performance.

A numerical simulation knot of the method 1 according to the first embodiment of the present invention will be described below with reference to the accompanying drawings.

1 1

fruit. Figure 2a shows the decorrelation effect using the precoding matrix 1-1, ie, in the method 1, Lin = ^Q. Figure 2b shows the corresponding ratio of the two layers of signal strength, ie P, H in method 1. Although the decorrelation effect is very obvious in this case, the signal strength difference between the two layers is also very large.

1 1

Figure 3a shows the decorrelation effect using the precoding matrix, ie = ^/6 in method 1. Figure 3b shows the corresponding ratio of the two layers of signal strength, ie P in the method 1, ^ = π ΐ 6. Increasing CDD precoding can reduce the signal strength difference between the two layers, but will therefore attenuate the decorrelation effect. Due to the very high SNR in the MBSFN environment, an 15dB imbalance is acceptable.

It should be understood that for the M*M MIM0 system, the channel transmission matrix can be precoded using CDD precoding. Method 2 according to a second embodiment of the invention 2

Another precoding method can be tried. A straightforward method for implementing an orthogonal channel matrix is: The equivalent MIM0 channel corresponding to a particular precoding matrix E is H - H _W R^E = H _W I.

1 - λ

Therefore, the precoding matrix E has the following form: - λ 1 g is a normalization coefficient. For example, when ^ ⁰ · ⁹⁹ = 0.867; Ρ = 0.9 when A = 0.627; and P = ⁰ · ⁸ when A = 0.5 In this method, set the precoding matrix as follows:

The equivalent ΜΙΜ0 channel is ^{H = H} w ^R T ^b . Then the correlation between the channel coefficients and the signal strength ratios of the two layers can be derived as follows - \2λ - (λ ² + \)ρ

Ρ

λ + 1 - 2λρ Ρ (10) Figure 4a shows the use of precoding matrix

That is, Ρ in Method 2, λ = 0.627 ₀ Figure 4b shows the corresponding ratio of the two layers of signal strength, that is, p, = 0. ^{627 in} Method 2. Although the decorrelation effect is very obvious in this case, when in the NL0S environment, the decorrelation of the two layers can be broken. In the previous section, when 一|ι .254 - 1.393 ?|

At 0.627,

= 1.393 - 1.25V, then the correlation between the two layers after precoding is shown in the following table:

Figure 5a shows the use of a precoding matrix

That is, P in Method 2, A = 0.333. Figure 5b shows the corresponding ratio of the two layers of signal strength, ie p, = 0.333 in method 2. Decreasing the L of the precoding matrix balances the correlation between the two layers after precoding in the NL0S and L0S environments. Based on the foregoing analysis and the numerical simulation in Figure 5, A = 0.333 is suitable.

One of ordinary skill in the art will appreciate that for an M*M MIM0 system, the equivalent MIM0 channel transmission matrix corresponding to a particular precoding matrix E is a diagonal matrix. Method 3 according to a third embodiment of the invention

A third precoding method can be tried. The equivalent MIM0 channel corresponding to the specific precoding matrix E is the direct method for implementing the orthogonal channel matrix.

g is the normalization coefficient. For example, at the time = 0-86 _; Ρ = 0.9 = 0.621 Ρ = 0.8 when t = o.5.

In this method, the precoding matrix is set as follows:

The equivalent ΜΙΜΟ channel is ^{H = H} w ^R T ^D . Then you can derive the channel coefficients and two layers. The correlation of the signal strength ratios is as follows:

1 + 7

P ? , P = Ρ · 2(1 + )

(1 - A): (1 - A): (12) The numerical simulation of Method 3 is as follows

0.373 - 0.629

0.937 ·

Figure 6a shows the use of precoding matrix 0.373 1

The decorrelation effect, ie Ρ in method 3, λ = 0.627 ₀ Figure 6b shows the corresponding ratio of the two layers of signal strength, ie p in the method 3, ^ = 0.627 ₀ despite the decorrelation effect in this case It is sufficient. Conversely, when it is in the NLOS environment, the signal strength difference between the two layers becomes very large. In section 4. 2. 3, if A = 0.627,

As shown in Fig. 6b, when ⁷ → ^Q , the ratio of the two layers of signal strength after precoding is derived to be 7 dB.

Additional gain can be added to the first layer to balance the two layers of signal strength after precoding in the NLOS and L0S environments. Figure 7a shows the decorrelation effect using the precoding matrix, ie P, Si in method 3.

7b shows the corresponding ratio of the two layers of signal strength, ie ρ, ^{= 1} · ^{414 in} method 3. The figure shows a curve offset by 3 dB after precoding.

One of ordinary skill in the art will appreciate that for an M*M MIM0 system, the equivalent MIM0 channel transmission matrix corresponding to a particular precoding matrix E is a lower triangular matrix. Signal de-correlation in the L0S environment in open-loop SM by precoding methods must be sacrificed in other respects. For example, the equalization of the two layers of signal strength in Method 1 and Method 3, and the correlation of the two layers in the NL0S environment in Method 2. Based on the analysis and numerical simulation, these precodings are a viable solution for the SF ring SF in the SF. method

Method 2:

Method 3:

0.627, and g, = .

It is considered here that the SNR in SFN operation is high enough to withstand the difference between the two layers of signal strength (up to 10 dB).

It should also be understood that the steps described in the above embodiments of the present invention may also be implemented by a channel precoding apparatus that performs the channel precoding method as described above.

Here, the CDD precoding recommended in Method 1 and the diagonal precoding recommended in Method 2 are simulated to observe performance.

The link level simulation results for the system are shown below.

The main link level simulation parameters are listed in Table 1.

Table 1 link simulation hypothesis Figure 8 shows the performance of Method 2 at link level emulation. Here

It can be seen from Figure 8 that in the case of high channel correlation, the precoding can at least provide a gain of 2 dB. But the more important thing is: Precoding can change the CDF of relevance. So from a statistical point of view, system-level simulation results can illustrate more benefits.

The system level simulation results are described below.

The main system level simulation parameters are listed in Table 2.

Table 2 System level simulation assumptions

Figure 9 shows the BLER (Block Error Rate) curve received by the UE, the physical link is 16QAM, 2/3t _U rbo coding and 2*2 open-loop spatial multiplexing system, so the transmission efficiency is about 3.84bit/s/ Hz, regardless of overhead. Figure 9a shows the UE moving within a 300m radius of the cell. The result of the motion, and Figure 9b is the result of the UE moving within a 100 meter radius within the cell. Method 2 using a precoding method, wherein

λ = 0.333

The corresponding CDF of the correlation is again shown in FIG.

Usually in the spatial channel model, the probability of L0S is defined as 1 at a distance of 0, and linearly decreases until a cutoff point at d300m, where the likelihood of LOS is zero.

For the case of L0S, the Ricean K factor is a simplified version based on K 2 13-0. 03*d (dB), where d is the distance in meters between the MS and the BS. Therefore, when the UE is in the vicinity of the eNB, whether it is fixed or in a limited area, the channel correlation due to the L0S will be very large. As shown in Figure 10a, in this case, there is a 59% likelihood correlation > 0. 9, and it seems that there is a 42% likelihood correlation > 0.95. This will cause more degradation in reception performance. As shown in Figure 10b, the average BLER is up to 11%.

Precoding can attenuate the effects of channel correlation in spatial multiplexing systems. The net effect is that the average BLER is reduced to 3%, which is similar to the effect of NL0S. However, when the UE moves away from the eNB or moves over a larger area, the correlation overlaps with the NL0S, as shown in Figures 9a and 9b, which does not provide more gain.

Figure 11 shows the BLER curve received by the UE. The physical link is 16QAM, 2/3 Turbo code, and 2*2SM, so the transmission efficiency without considering overhead is about 3.84 bit/s/Hz. The figure 10a gives the result of the UE moving within the 300πι radius of the cell, and Figure 1 ib gives the result of the UE moving within the 100m radius of the cell. Using the precoding method of method 1,

Figure 12 again shows the corresponding CDF of the correlation.

Precoding can attenuate the effects of channel correlation in spatial multiplexing systems. As shown in Figure 12b, after precoding, there is a 17% probability of correlation of 0.9, and it can be seen that there is a 9% likelihood correlation > 0.95. The net effect is that the average BLER is reduced to 2%, even lower than the average BLER of the NL0S as shown in Figure ib. When the UE moves away from the eNB or moves within a large area, the gain is not There are so many, as shown in Figure 11a. Even the average BLER decreased from 5% to 2.5%.

The advantages of the solution of the invention are: 1) Precoding can minimize the effects of channel correlation in a spatially multiplexed system. There is a 9% probability of correlation > 0.99 in the L0S channel after precoding. However, if there is no precoding, the number is 42%; 2) The UE can use demultiplexing and detect signals very well, which greatly improves the transmission quality of the E-MBMS service, see the simulation results, and does not introduce any additional complexity. 3) Applies to the open-loop MIM0 in MBSFN. The present invention has good detection capabilities: First, the present invention is positioned for potential standardization of 3GPP LTE+ and China 4G; secondly, many specific control signaling is required on the air interface, such as a codebook represented by e B, eNB and UE Both must be aware of the applied precoding scheme and ensure that the precoding scheme is detectable.

It will be understood by those skilled in the art that all or part of the steps of implementing the foregoing embodiments may be completed by a program instructing related hardware, and the program may be stored in a computer readable storage medium, and executed according to the present invention. In the above method of the embodiment of the invention, the storage medium may be a storage medium such as a ROM/RAM, a magnetic disk, or an optical disk.

While a few embodiments of the present invention have been shown and described, the embodiments of the invention Changes are made in the examples.

Claims

Rights request

A channel precoding method applied to an open loop spatial multiplexing system of a MIM0 system, wherein H is a channel transmission matrix of a MIM0 system, and the channel precoding method precodes a signal of an input channel such that the channel The transmission matrix has the largest det(H'H), allowing the open-loop spatial multiplexing system to achieve maximum capacity.

The method according to claim 1, wherein the precoding makes the signal strengths of the layers of the MIM0 system equal and orthogonal to each other, that is, the channel transmission matrix H of the MIM0 is an orthogonal diagonal matrix.

3. The method according to claim 1, wherein in the precoding MIM0 system, an equivalent MIM0 channel corresponding to a specific precoding matrix E can be reconstructed by applying H _E =HE.

The method of claim 3, wherein for the M*M MIM0 system, the channel transmission matrix is precoded using a cyclic delay diversity CDD precoding scheme.

The method according to claim 4, wherein for the MIM0 channel transmission matrix of rank two, an equivalent MIM0 channel corresponding to a specific precoding matrix is H = H _W R^E, said precoding matrix

6. The method of claim 5, wherein for a 2*2 MIM0 system, equivalent

MIMO channel is

7. The method of claim 3, for an M*M MIMO system, the equivalent MIM0 channel transmission matrix corresponding to a particular precoding matrix E is a diagonal matrix.

8. The method according to claim 7, wherein for a 2*2 MIM0 system, an equivalent MIM0 channel corresponding to a specific precoding matrix E is H = H _W R^ ^/2 E = H _W I ,

9. The method of claim 8 wherein l = (3 ³ .

10. The method of claim 3, wherein for a M*M MIM0 system, with a specific pre- The equivalent MIMO channel transmission matrix corresponding to the coding matrix E is a lower triangular matrix.

11. The method according to claim 10, wherein for a 2*2 MIM0 system, an equivalent MIMO corresponding to a specific precoding matrix E

The method according to claim 11, wherein said precoding matrix D has the following shape

Λ - λ - λ

g

Formula: \ - λ l

13. The method of claim 12, wherein = 0.627 and = .

14. A channel precoding apparatus, applied to an open loop spatial multiplexing system of a MIM0 system, wherein H is a channel transmission matrix of a MIM0 system, and the channel precoding apparatus precodes a signal of an input channel such that the channel The transmission matrix has the largest ^det (TM), which allows the ring space spatial multiplexing system to achieve maximum capacity.

The channel precoding apparatus according to claim 14, wherein said precoding means causes signal layers of the MIM0 system to be equal and orthogonal to each other, i.e., the channel transmission matrix H of MIM0 is an orthogonal diagonal matrix.

16. The channel precoding apparatus according to claim 14, wherein in the precoding MIM0 system, an equivalent MIM0 channel corresponding to a specific precoding matrix E can be reconstructed by applying H _E = HE.

The channel precoding apparatus according to claim 16, wherein for the M*M MIM0 system, the channel transmission matrix is precoded using a CDD precoding method.

The channel precoding apparatus according to claim 17, wherein for a MIM0 channel transmission matrix of rank = 2, an equivalent MIM0 channel corresponding to a specific precoding matrix is

1 1 1 1

E = \ E _n =

1 - 1

L ' V2 j - j

H = H _w RE , the precoding matrix.

The channel precoding apparatus according to claim 18, wherein for a 2*2 MIM0 system, an equivalent MIM0 channel is ^{H = H} w ^R ^ ^c , and the precoding matrix E = C, wherein

C =

7?L - e Κ = ττ

20. The channel precoding apparatus according to claim 16, wherein for the M*M MIM0 system, the equivalent MIM0 channel transmission matrix corresponding to the specific precoding matrix E is a diagonal matrix.

The channel precoding apparatus according to claim 20, wherein for a 2*2 MIM0 system, an equivalent MIM0 channel corresponding to a specific precoding matrix E is H = H _W R^E = H _W I ,

22. The channel precoding apparatus according to claim 21, wherein A = 0.333.

The channel precoding apparatus according to claim 16, wherein for the M*M MIMO system, the equivalent MIM0 channel transmission matrix corresponding to the specific precoding matrix E is a lower triangular matrix.

24. The channel precoding apparatus according to claim 23, wherein for the 2*2 MIM0 system, the equivalent MIM0 channel corresponding to the specific precoded matrix E is = 1 "g, (b) - λ

1 0 D

Η = H _W R ² D = H

1 1

The channel precoding apparatus according to claim 24, wherein said precoding matrix D has the following form:

26. The channel precoding apparatus according to claim 25, wherein 1 = 0. ⁶²⁷ and.

! 8