CN102904687A - Method and device for sequencing in multi-layer MIMO (Multiple Input Multiple Output) sphere decoding detection - Google Patents

Abstract

The invention discloses a method and a device for sequencing in multi-layer MIMO (Multiple Input Multiple Output) sphere decoding detection. After a channel matrix solves once pseudo-inverse, the MIMO layer is sequenced; when sequencing is carried out, pruning is preferential and modulation is considered; and the MIMO layer is divided into a pruning layer and a non-pruning layer. The technology for sequencing in multi-layer MIMO sphere decoding detection provided by the invention can avoid solving the pseudo inverse by multiple matrixes in the traditional method and reduce the complexity greatly; in the non-pruning layer, a high-modulation mode is arranged at the top layer of the MIMO detection as much as possible, so that the reduced branch number can be reduced as soon as possible in the FSD (Full-Scale Deflection) operation process and the detection performance can be optimized.

Description

The method and apparatus that in multilayer MIMO globular decoding detects, sorts

Technical field

The present invention relates to the communications field, be specifically related to a kind of method and apparatus that in multilayer MIMO globular decoding detects, sorts.

Background technology

Multiple-input and multiple-output (Multiple Input Multiple Output, MIMO) detecting is to realize in the wireless communication system that spectral efficient is with one of key technology of improving power system capacity, it also is the key property that 3GPP strengthens Long Term Evolution (LTE-Advanced, LTE-A) system.Because International Telecommunications Union-IMT-Advanced (ITU IMT-Advanced) is for the spectral efficient requirement of system, LTE-A proposes spectrum efficiency will reach descending 30bps/Hz and up 15bps/Hz.In order to satisfy these indexs, LTE-A has adopted descending maximum 8 layers of MIMO, up maximum 4 layers of MIMO, and multilayer MIMO detection technique just becomes one of key technology that determines the LTE-A receiver performance.

In the MIMO detection technique, globular decoding (sphere decoding, SD) detects can approach optimal performance on performance, be maximum likelihood (maximum likelihood, ML) performance, and therefore complexity often is used to carry out MIMO and detects far below ML.Wherein, for having the fixedly globular decoding of complexity characteristics (fixed-complexity sphere decoding, FSD), owing in every one deck detects, select fixing the survival node that distance is minimum to calculate the search extension path, therefore complexity is fixed, and often is used for carrying out MIMO by end side and detects.Detect for the multilayer MIMO in the LTE-A system, the main flow process of FSD comprises that equivalent channel matrix generation, ordering, QR decompose, the spherical search and LLR (maximum likelihood output) output as shown in Figure 1, and wherein first three part all belongs to preprocessing part.Ordering in the preliminary treatment is according to concrete searching method each layer detected energy size to be arranged, and chooses suitable detection order and detects performance to improve.

Conventional FSD thinks the modulation system that each layer employing is identical, but each layer can adopt different modulation systems in the LTE-A system.How to carry out rational sorting in the multilayer MIMO globular decoding of supporting the different modulating mode detects, so that performance is approached optimal performance, be present problem demanding prompt solution.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of method and apparatus that sorts in multilayer MIMO globular decoding detects,

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of method that in multilayer multiple-input and multiple-output MIMO globular decoding detects, sorts, the method comprises: in the ordering of channel matrix being asked laggard hand-manipulating of needle of pseudoinverse to the MIMO layer; When carrying out described ordering, beta pruning is preferential and take into account modulation; Described MIMO layer is divided into beta pruning layer and two part of non-beta pruning layer.

Consider first the beta pruning factor when carrying out described ordering, consider again the impact of modulation system.

When not having the beta pruning layer segment in the described MIMO layer, the MIMO layer that the high modulation mode is corresponding comes before the low modulation mode first, then in MIMO layer corresponding to identical modulation system, by the detected energy ordering.

When the beta pruning layer segment only sorts by detected energy, confirm not consider concrete modulation system.

The process of described ordering comprises:

Suppose that H is equivalent channel matrix, calculate the pseudoinverse of H

Wherein subscript H represents conjugate transpose, and-1 expression is inverted;

At first begun to arrange by non-beta pruning layer segment;

When not having the beta pruning layer segment in the MIMO layer, each layer of MIMO arranged from high to low by modulation system; In MIMO layer corresponding to identical modulation system, sequence number Row j ∈ Ω wherein, Ω is the set of MIMO layer corresponding to identical modulation system; Order (.) is sorting operation, and 2 norms of each row of H are by descending order ordering, the ascending ordering of channel energy of corresponding institute detection layers.

Described method also comprises: do not consider the impact of each layer distribution different modulating mode for beta pruning part, directly press the ascending ordering of channel energy of detection layers during ordering, sequence number

Wherein row j is the sequence number of the corresponding MIMO layer of beta pruning layer segment.

A kind of device that in multilayer MIMO globular decoding detects, sorts, this device is used for:

In the ordering of channel matrix being asked laggard hand-manipulating of needle of pseudoinverse to the MIMO layer; When carrying out described ordering, beta pruning is preferential and take into account modulation;

Described MIMO layer is divided into beta pruning layer and two part of non-beta pruning layer.

Described device is used for considering the beta pruning factor first when carrying out described ordering, considers the impact of modulation system again.

When not having the beta pruning layer segment in the described MIMO layer, described device is used for first that the high modulation mode is corresponding MIMO layer and comes before the low modulation mode, then in MIMO layer corresponding to identical modulation system, by the detected energy ordering.

When the beta pruning layer segment only sorted by detected energy, described device was used for confirming not consider concrete modulation system.

Described device is used for when carrying out described ordering:

Suppose that H is equivalent channel matrix, calculate the pseudoinverse of H

Wherein subscript H represents conjugate transpose, and-1 expression is inverted;

At first begun to arrange by non-beta pruning layer segment;

When not having the beta pruning layer segment in the MIMO layer, each layer of MIMO arranged from high to low by modulation system; In MIMO layer corresponding to identical modulation system, sequence number Row j ∈ Ω wherein, Ω is the set of MIMO layer corresponding to identical modulation system; Order (.) is sorting operation, and 2 norms of each row of H are by descending order ordering, the ascending ordering of channel energy of corresponding institute detection layers.

Described device also is used for when carrying out described ordering: do not consider the impact of each layer distribution different modulating mode for beta pruning part, during ordering by the ascending ordering of detected energy, sequence number

Wherein row j is the sequence number of the corresponding MIMO layer of beta pruning layer segment.

Described device is base station and/or subscriber equipment.

The technology that the present invention sorts in multilayer MIMO globular decoding detects can be avoided the repeatedly Matrix Calculating pseudoinverse of conventional method, greatly reduce complexity, and at non-beta pruning layer the high modulation mode is placed on the top layer that MIMO detects as far as possible, can guarantee that the branch number of cutting down in the FSD operating process is the least possible, thereby make the detection performance reach optimum.

Description of drawings

Fig. 1 is fixing complexity globular decoding overhaul flow chart;

Fig. 2 is the principle schematic that sorts in multilayer MIMO globular decoding detects of the embodiment of the invention;

Fig. 3 a and Fig. 3 b are respectively the performance schematic diagram that the lower 4 layers of MIMO of 3GPP LTE-A different modulating mode detect;

Fig. 4 is the general flow chart that sorts in multilayer MIMO globular decoding detects of the embodiment of the invention.

Embodiment

In actual applications, can after channel matrix being asked a pseudoinverse, just sort, and not ask the repeatedly cycling of pseudoinverse;

When carrying out described ordering, can be based on beta pruning preferential and take into account the principle of modulation, consider first the beta pruning factor when namely sorting, consider again the impact of modulation system; Described beta pruning is exactly to carry out knot removal when SD detection and every layer of branch of expansion downwards, and the nodes that keeps is less than all obtainable nodes.When not having the beta pruning layer segment in the MIMO layer, the MIMO layer that the high modulation mode is corresponding comes before the low modulation mode first, then in MIMO layer corresponding to identical modulation system, by the detected energy ordering.If the beta pruning layer segment only by the detected energy ordering, then needn't be considered the impact of each layer distribution different modulating mode.

Detect for multilayer MIMO, can carry out as shown in Figure 1 equivalent channel matrix generation, ordering, QR decomposition, spherical search and LLR output, wherein the process of ordering comprises:

Suppose that H is equivalent channel matrix, calculate the pseudoinverse of H

Wherein subscript H represents conjugate transpose, and-1 expression is inverted;

When practical application, for asking the contrary of multi-dimensional matrix can adopt the simplification of following inversion of partitioned matrix to calculate, take the 4x4 matrix as example:

If $G=H^{H}H=\left[\begin{array}{cccc}{g}_{00}& g_{01}& g_{02}& g_{03}\\ g_{10}& g_{11}& g_{12}& g_{13}\\ g_{20}& g_{21}& g_{22}& g_{23}\\ g_{30}& g_{31}& g_{32}& g_{33}\end{array}\right]=\left[\begin{array}{cc}A& B\\ C& D\end{array}\right];$

A wherein, B, C and D are the 2x2 matrixes:

$A=\left[\begin{array}{cc}{g}_{00}& g_{01}\\ g_{10}& g_{11}\end{array}\right],$ $B=\left[\begin{array}{cc}{g}_{02}& g_{03}\\ g_{12}& g_{13}\end{array}\right],$ $C=\left[\begin{array}{cc}{g}_{20}& g_{21}\\ g_{30}& g_{31}\end{array}\right],$ $D=\left[\begin{array}{cc}{g}_{22}& g_{23}\\ g_{32}& g_{33}\end{array}\right];$

Matrix inversion $G^{-1}=\left[\begin{array}{cc}{A}^{-1}+A^{-1}B{(D-{\mathrm{CA}}^{-1}B)}^{-1}{\mathrm{CA}}^{-1}& {-A}^{-1}B{(D-{\mathrm{CA}}^{-1}B)}^{-1}\\ -{(D-{\mathrm{CA}}^{-1}B)}^{-1}{\mathrm{CA}}^{-1}& {(D-{\mathrm{CA}}^{-1}B)}^{-1}\end{array}\right];$

Wherein, the 2x2 matrix inversion can directly be provided by following formula (take A as example, B, C and D are similar):

$A^{-1}={\left[\begin{array}{cc}{g}_{00}& g_{01}\\ g_{10}& g_{11}\end{array}\right]}^{-1}=\frac{1}{(g_{00}{g}_{11}-g_{01}{g}_{10})}\left[\begin{array}{cc}{g}_{11}& -g_{01}\\ {-g}_{10}& {\mathrm{<figure-callout\; id="00"\; label="g"\; filenames="HDA00002242788800021.png"\; state="\{\{state\}\}">g</figure-callout>}}_{00}\end{array}\right];$

Ask the pseudoinverse of H

For each column vector wherein J=0,1,2,3 o'clock can be in the hope of 2 norms (can be considered the channel energy of institute's detection layers) of correspondence, such as

Fig. 2 has provided concrete ordering principle, and each layer of MIMO is divided into beta pruning layer and two part of non-beta pruning layer, is begun to arrange by non-beta pruning layer segment;

For there not being the beta pruning layer segment in the MIMO layer, each layer of MIMO arranged from high to low by modulation system.In MIMO layer corresponding to identical modulation system, sequence number

Row j ∈ Ω wherein, Ω is the set of MIMO layer corresponding to identical modulation system; Order (.) is sorting operation, and 2 norms of each row of H are by descending order ordering, the ascending ordering of channel energy of corresponding institute detection layers.

For the beta pruning part in the MIMO layer, can not consider the impact of each layer distribution different modulating mode, press the ascending ordering of detected energy, sequence number during ordering

Wherein row j is the sequence number of the corresponding MIMO layer of beta pruning layer segment.

In concrete applied environment, advantage of the present invention can be described according to the emulation of LTE-A system receiver.The high modulation mode of system is 64QAM (quadrature amplitude modulation), secondly is 16QAM, QPSK.Concrete simulated conditions is with reference to the 3GPP standard, as shown in Table 1.Wherein, soft fixedly complexity globular decoding represents that the ground floor of MIMO layer does not carry out beta pruning when detecting (Soft fixed-complexity sphere decoding, SFSD) parameter choosing (x211), and all the other each layers carry out beta pruning.

Table one

Behind the Block Error Rate (BLER) and throughput (Throughput) performance of more multiple possibility sequencing schemes, obtain the concrete simulation result shown in Fig. 3 a and Fig. 3 b; Wherein,

Mode (Way) 1: detect first the MIMO layer of respective channels energy minimum in the 64QAM layer, all the other each layers are pressed the ascending sequence detection of energy;

Way2: detect first one deck of energy minimum in the 64QAM layer, all the other each layers are pressed the descending sequence detection of energy;

Way3: one deck of first detected energy minimum, all the other each layers are pressed the descending sequence detection of energy;

Way4: detect first the 64QAM layer, the ascending ordering of channel energy; Rear detection QPSK (Quadrature Phase Shift Keying) layer, the descending ordering of channel energy;

Way5: detect first the 64QAM layer, the ascending ordering of channel energy; Rear detection QPSK layer, the ascending ordering of channel energy;

Way6: detect first the QPSK layer, the ascending ordering of channel energy; Rear detection 64QAM layer, the descending ordering of channel energy;

Way7: detect first the QPSK layer, the ascending ordering of channel energy; Rear detection 64QAM layer, the ascending ordering of channel energy;

Way8: detect first one deck of energy minimum in the QPSK layer, all the other each layers detect by the descending ordering of channel energy;

Way9: detect first the QPSK layer, rear detection 64QAM layer does not carry out energy ordering;

Way10: detect first one deck of energy minimum in the QPSK layer, all the other each layers detect by the ascending ordering of channel energy;

Way11: detect first the 64QAM layer, rear detection QPSK layer does not carry out energy ordering.

Above-mentioned 11 kinds of modes have contained following situation: beta pruning of the present invention preferentially take into account modulation (Way1), modulation preferentially take into account energy (Way4/5/6/7), only consider energy (Way3), only consider modulation (Way9/11).Can find out that by contrasting with ML the relative additive method of the present invention can reach the performance of more approaching ML, and can avoid the repeatedly Matrix Calculating pseudoinverse of conventional method, greatly reduce the complexity of processing.

In conjunction with above description as can be known, the operation thinking that the present invention sorts in multilayer MIMO globular decoding detects can represent flow process as shown in Figure 4, and this flow process may further comprise the steps:

Step 410: in the ordering of channel matrix being asked laggard hand-manipulating of needle of pseudoinverse to the MIMO layer;

Step 420: when carrying out described ordering, beta pruning is preferential and take into account modulation.

Need to prove that the technology that the present invention sorts both can be applied to also can be applied in the subscriber equipment in the base station in multilayer MIMO globular decoding detects.

In sum as seen, no matter be method or the device of manner of execution, the technology that the present invention sorts in multilayer MIMO globular decoding detects can be avoided the repeatedly Matrix Calculating pseudoinverse of conventional method, greatly reduce complexity, and at non-beta pruning layer the high modulation mode is placed on the top layer that MIMO detects as far as possible, can guarantee that the branch number of cutting down in the FSD operating process is the least possible, thereby make the detection performance reach optimum.

The above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.

Claims (13)

1. method that sorts in multilayer multiple-input and multiple-output MIMO globular decoding detects is characterized in that the method comprises:

In the ordering of channel matrix being asked laggard hand-manipulating of needle of pseudoinverse to the MIMO layer; When carrying out described ordering, beta pruning is preferential and take into account modulation;

Described MIMO layer is divided into beta pruning layer and two part of non-beta pruning layer.

2. method according to claim 1 is characterized in that, considers first the beta pruning factor when carrying out described ordering, considers the impact of modulation system again.

3. method according to claim 2 is characterized in that,

When not having the beta pruning layer segment in the described MIMO layer, the MIMO layer that the high modulation mode is corresponding comes before the low modulation mode first, then in MIMO layer corresponding to identical modulation system, by the detected energy ordering.

4. method according to claim 3 is characterized in that, when the beta pruning layer segment only sorts by detected energy, confirms not consider concrete modulation system.

5. according to claim 1 to 4 each described methods, it is characterized in that the process of described ordering comprises:

Suppose that H is equivalent channel matrix, calculate the pseudoinverse of H Wherein subscript H represents conjugate transpose, and-1 expression is inverted;

At first begun to arrange by non-beta pruning layer segment;

When not having the beta pruning layer segment in the MIMO layer, each layer of MIMO arranged from high to low by modulation system; In MIMO layer corresponding to identical modulation system, sequence number Row j ∈ Ω wherein, Ω is the set of MIMO layer corresponding to identical modulation system; Order (.) is sorting operation, and 2 norms of each row of H are by descending order ordering, the ascending ordering of channel energy of corresponding institute detection layers.

6. method according to claim 5 is characterized in that, the method also comprises:

Do not consider the impact of each layer distribution different modulating mode for beta pruning part, directly press the ascending ordering of channel energy of detection layers during ordering, sequence number

Wherein row j is the sequence number of the corresponding MIMO layer of beta pruning layer segment.

7. device that sorts in multilayer MIMO globular decoding detects is characterized in that this device is used for:

In the ordering of channel matrix being asked laggard hand-manipulating of needle of pseudoinverse to the MIMO layer; When carrying out described ordering, beta pruning is preferential and take into account modulation;

Described MIMO layer is divided into beta pruning layer and two part of non-beta pruning layer.

8. device according to claim 7 is characterized in that, described device is used for considering the beta pruning factor first when carrying out described ordering, considers the impact of modulation system again.

9. device according to claim 8 is characterized in that,

When not having the beta pruning layer segment in the described MIMO layer, described device is used for first that the high modulation mode is corresponding MIMO layer and comes before the low modulation mode, then in MIMO layer corresponding to identical modulation system, by the detected energy ordering.

10. device according to claim 9 is characterized in that, when the beta pruning layer segment only sorted by detected energy, described device was used for confirming not consider concrete modulation system.

11. to 10 each described devices, it is characterized in that described device is used for when carrying out described ordering according to claim 7:

Suppose that H is equivalent channel matrix, calculate the pseudoinverse of H

Wherein subscript H represents conjugate transpose, and-1 expression is inverted;

At first begun to arrange by non-beta pruning layer segment;

When not having the beta pruning layer segment in the MIMO layer, each layer of MIMO arranged from high to low by modulation system; In MIMO layer corresponding to identical modulation system, sequence number

Row j ∈ Ω wherein, Ω is the set of MIMO layer corresponding to identical modulation system; Order (.) is sorting operation, and 2 norms of each row of H are by descending order ordering, the ascending ordering of channel energy of corresponding institute detection layers.

12. device according to claim 11 is characterized in that, described device also is used for when carrying out described ordering:

Do not consider the impact of each layer distribution different modulating mode for beta pruning part, during ordering by the ascending ordering of detected energy, sequence number

Wherein row j is the sequence number of the corresponding MIMO layer of beta pruning layer segment.

13. device according to claim 7 is characterized in that, described device is base station and/or subscriber equipment.

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