CN103795503A - QR decomposition detection method - Google Patents

Abstract

The invention belongs to the technical field of mobile communication, and particularly relates to a QR decomposition detection method under a novel system combined with spatial modulation and quasi-orthogonal space time block codes. The QR decomposition detection method comprises the steps that first, antenna combined modes are selected and traversed, and an equivalent channel submatrix corresponding to an activated antenna combined index is obtained; QR decomposition is conducted on the equivalent channel sub matrix, so that an upper triangular matrix R is obtained; afterwards, the last sign is demodulated, judgment is made by using a maximum-likelihood criterion, and when other signs are detected, interference of the detected signs is sequentially subtracted. Due to the fact that each antenna combined mode corresponds to a set of solution vectors, the Euclidean distance between received signals is calculated respectively, the solution vector corresponding to the minimum value serves as an optimal detection sending signal, the corresponding sending combination is an activated sending antenna combination. Through QR decomposition, the searching frequency can be reduced, the detection complexity of a receiver is lowered, and excellent detection performance can be achieved under the low complexity condition.

Description

A kind of QR decomposes detection method

Technical field

The invention belongs to mobile communication technology field, the QR being specifically related under a kind of new system that a kind of spatial modulation is combined with quasi-orthogonal space time block code decomposes detection method.

Background technology

Spatial modulation (Spatial Modulation, SM) information bit of some is divided into two parts by technology, the transmitting antenna of a part for selecting to activate, another part is mapped to constellation symbol for modulation, and the constellation symbol of mapping is transmitted by the transmitting antenna of selecting, non-selected transmitting antenna is mourned in silence.Adopt SM technology can avoid in multiple-input and multiple-output (Multiple-Input Multiple-Output, MIMO) system problem, the problem includes: the synchronous problem of interchannel interference and transmitting antenna.SM system only activates a transmit antennas at every turn, and other antennas are mourned in silence.Space-Time Block Coding (Space Time Block Code, STBC), as the Typical Representative of mimo system Space-Time Codes, receives much concern because it can utilize diversity technique effectively to resist multipath fading.Orthogonal space time packet (the Orthogonal Space Time Block Code that Alamouti etc. propose, OSTBC) can obtain maximum diversity gain, but, in addition, other forms of orthogonal coding is rate transmission at full speed all, cause overstocking of transmitting terminal data, can not realize high-speed transfer.Jafarkhani etc. have proposed quasi-orthogonal space time block code Quasi-Orthogonal Space Time Block Code, QOSTBC) concept, the method can realize full velocity transmission, but due to accurate orthogonality, can only obtain the diversity gain of part.Maximum likelihood (Maximum Likelihood, ML) detects has optimum detection performance, but complexity is along with the increase exponentially of number of transmit antennas doubly goes up.Quick response matrix code (Quick Response Code, QR) decomposes detection algorithm and has nearly Maximum Likelihood Detection performance and lower complexity.

Summary of the invention

The object of the present invention is to provide the QR under a kind of new system that a kind of spatial modulation is combined with quasi-orthogonal space time block code to decompose detection method, overcome the defect of prior art.

Object of the present invention realizes as follows:

The mapping table one by one of S1, setting emitting antenna combination and bit, wherein, transmission antenna group is combined into adjacent E transmitting antenna composition, the compound mode of total t group antenna;

The reception signal of S2, receiver is for being N _r× 1 column vector y=HX+n=H _subx _e+ n _sub, wherein, y=(y ₁, y ₂, y ₃..., y _e), E>=3 and E are natural number, N _rfor reception antenna number, the N that H is mimo system _r× N _tchannel matrix, X is the N of the spatial modulation system transmitter of being combined with quasi-orthogonal space time block code _t× E transmitted signal, X _efor QOSTBC encoder matrix, in X, the submatrix of the capable formation of non-zero is X _e, H _subfor the antenna combined index that is activated corresponds to the channel submatrix of the respective column index in channel matrix H, n is that average is that 0 variance is σ ²additive white Gaussian noise;

When S3, receiving terminal detect, for each possible antenna combination, correspondence solves detected symbol and calculates corresponding Euclidean distance respectively, comprising:

When S31, detection, utilize equivalent channel matrix H _e, receiving terminal is equivalent to wherein,

$\tilde{y}=(y_1,{y_2}^{\′},y_3,...,{y_E}^{\′}),$ X＝(x ₁,x ₂,x ₃,...,x _E)；

S32, to equivalent channel matrix H _ecarry out QR decomposition, Q is unitary matrice, and R is upper triangular matrix, wherein Q ^hq=1;

S33, right $\tilde{y}=H_{E}X+\tilde{n}$ Both sides are with taking advantage of Q ^h, that is, $Q^H\tilde{y}=\mathrm{RX}+Q^H\tilde{n};$

S34, order

?

utilize the mode of traversal constellation point to obtain solution symbol

when symbol detection then, deduct successively the interference of the symbol having detected and utilize traversal mode to obtain solution symbol, last solution vector

S35, calculating Euclidean distance,

this norm of not Luo Beini crow square.

Further, the transmission antenna group described in S1 is combined into adjacent E transmitting antenna composition, and emitting antenna combination all can be used as one group of antenna combination being activated arbitrarily.

The invention has the beneficial effects as follows: the QR under the system of being combined with quasi-orthogonal space time block code in spatial modulation decomposes detection algorithm, decompose and obtain upper triangular matrix R and unitary matrice Q by the QR to equivalent matrix, then last receiving symbol is carried out to maximum likelihood decision detection, obtain optimal solution.Other symbols carry out Interference Cancellation and carry out maximum likelihood decision detection detected symbol successively, obtain optimum solution symbol.Irrelevant with the antenna number that is activated because of some when each maximum likelihood decision detects in the just planisphere of traversal, if adopt M-QAM modulation, only calculate M time Euclidean distance at every turn, the algorithm that the present invention proposes has reduced the complexity that receiving terminal detects.That is, the present invention decomposes by QR, can reduce the number of times of search, thereby has reduced the detection complexity of receiver, and obtains and preferably detect performance in the situation that of lower complexity.

Accompanying drawing explanation

Fig. 1 is emitting antenna combination mapping table and constellation mapping table.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described:

Set E=4, N _r=1.

The mapping table one by one of S1, setting emitting antenna combination and bit, wherein, transmission antenna group is combined into 4 adjacent transmitting antennas compositions, the compound mode of total t group antenna;

The reception signal of S2, receiver is for being N _r× 1 column vector y=HX+n=H _subx _e+ n _sub, wherein, y=(y ₁, y ₂, y ₃, y ₄), N _rfor reception antenna number, the N that H is mimo system _r× N _tchannel matrix, X is the N of the spatial modulation system transmitter of being combined with quasi-orthogonal space time block code _t× 4 transmitted signals, X ₄for QOSTBC encoder matrix, in X, the submatrix of the capable formation of non-zero is X ₄, H _subfor the antenna combined index that is activated corresponds to the channel submatrix of the respective column index in channel matrix H, n is that average is that 0 variance is σ ²additive white Gaussian noise, wherein, the coding of QOSTBC in the following way,

$X_4=\left[\begin{array}{cc}{A}_{12}& -A_{34}^{*}\\ A_{34}& A_{12}^{*}\end{array}\right]=\left[\begin{array}{cccc}{x}_1& -x_2^{*}& -x_3^{*}& x_4\\ x_2& x_1^{*}& -x_4^{*}& -x_3\\ x_3& -x_4^{*}& x_1^{*}& -x_2\\ x_4& x_3^{*}& x_2^{*}& x_1\end{array}\right];$

When S3, receiving terminal detect, for each possible antenna combination, correspondence solves detected symbol and calculates corresponding Euclidean distance respectively, comprising:

When S31, detection, utilize equivalent channel matrix H ₄, receiving terminal is equivalent to

wherein,

$\tilde{y}=(y_1,{y_2}^{\′},y_3,{y_4}^{\′}),X(x_1,x_2,x_3,x_4),H_4=\left[\begin{array}{cccc}{h}_1& h_2& h_3& h_4\\ h_2^{*}& -h_1^{*}& h_4^{*}& -h_3^{*}\\ h_3^{*}& h_4^{*}& -h_1^{*}& -h_2^{*}\\ h_4& -h_3& -h_2& h_1\end{array}\right];$

S32, to equivalent channel matrix H ₄carry out QR decomposition, Q is unitary matrice, and R is upper triangular matrix, wherein Q ^hq=1,

$R=\left[\begin{array}{cccc}{r}_{11}& r_{12}& r_{13}& r_{14}\\ 0& r_{22}& r_{23}& r_{24}\\ 0& 0& r_{33}& r_{34}\\ 0& 0& 0& r_{44}\end{array}\right];$

S33, right $\tilde{y}=H_{4}X+\tilde{n}$ Both sides are with taking advantage of Q ^h, that is, $Q^H\tilde{y}=\mathrm{RX}+Q^H\tilde{n};$

S34, order

?

utilize the mode of traversal constellation point to obtain solution symbol

when symbol detection then, deduct successively the interference of the symbol having detected and utilize traversal mode to obtain solution symbol, last solution vector

S35, calculating Euclidean distance,

this norm of not Luo Beini crow square.Because the combination to t kind transmitting antenna travels through, so there be t Euclidean distance value.Choose solution vector corresponding to wherein minimum value and send new number as last estimation, the antenna combination that its corresponding emitting antenna combination is activated as transmitting terminal simultaneously.

For the present invention will be described better, first introduce the system transmitter that technical solution of the present invention term used and spatial modulation are combined with quasi-orthogonal space time block code.

Emitting antenna combination: refer at transmitter N _tin transmit antennas, choose one group of combination of 4 of any vicinity, that chooses is called the transmitting antenna of activation, the non-selected transmitting antenna of mourning in silence that is called for 4 antennas of transmit information symbols.

Channel matrix: suppose to be flat fading channel between each transmitting antenna and each reception antenna, the channel matrix of mimo system is:

Wherein, N _rfor the reception antenna quantity of generalized spatial modulation system receiver, h _ijbe j, 1≤j≤N _ttransmit antennas is to i, 1≤i≤N _rthe fading coefficients of root reception antenna and obedience average are 0, the multiple Gaussian Profile that variance is 1.N in the present invention _rbe made as 1,

Equivalence Euclidean distance: equal the X that transmits ₄after channel H with not Luo Beini crow this norm, the i.e. equivalent Euclidean distance of received signal vector y

d _Euc＝||y-HX ₄|| _F。

Maximum likelihood decision criterion: refer to make the signal vector of equivalent Euclidean distance or its square value minimum as court verdict in the possible middle selection that transmits.

S101: in the system of being combined with quasi-orthogonal space time block code in spatial modulation, transmitter and receiver are shared emitting antenna combination mapping table and constellation mapping table, as shown in Fig. 1 in accompanying drawing.If the transmitter N of mimo system _ttransmit antennas, therefrom selects 4 contiguous total N _t-3 kinds of compound modes.Choose wherein the individual design for emitting antenna combination mapping table, represent to round downwards.

S201: in the digitlization binary message source data of supposing to need to send, frame data are b=(b ₁, b ₂, b ₃..., b _l), wherein L is frame length.B=0110110100 in this example, number of transmit antennas N _tbe 8.

S202: data are shunted, will

individual bit is used for selecting corresponding emitting antenna combination, another part data l ₂=L-l ₁be used for shining upon modulation constellation symbol, wherein M is order of modulation.B in this example ₁=01, l ₁=2, b ₂=10110100, l ₂=8.

S203: according to b ₁the combination of mapping antenna transmission.In this example, according to emitting antenna combination mapping table, 01 corresponding transmission antenna group is combined into (2,3,4,5).

S204: according to b ₂mapping modulation constellation symbol, obtains modulation constellation symbol

X=(x ₁, x ₂, x ₃, x ₄), it is carried out to QOSTBC coding.In this example, according to constellation mapping table, X=(1-i, 1-i ,-1+i, 1+i).Encoder matrix is as follows:

$X_4=\left[\begin{array}{cccc}-1-i& -1-i& 1+i& 1+i\\ 1-i& -1+i& -1+i& 1-i\\ -1+i& -1+i& -1+i& -1+i\\ 1+i& -1-i& 1+i& -1-i\end{array}\right];$

S205: the modulation constellation symbol data that the emitting antenna combination of selecting step S103 to obtain obtains step S104 is launched.In the transmitted signal of each time slot, only have 4 nonzero values, the location index at non-zero entry place is the antenna combination activating in S103.

S301: owing to need to all antenna combinations being traveled through and solve its corresponding solution vector.When receiving terminal detects, first to correspond to by antenna combined index the column index acquisition channel submatrix of channel matrix, it is carried out to transcoding, coding transform, obtain equivalent channel submatrix.The antenna sets activating in this example is combined into (2,3,4,5), and corresponding channel submatrix is H _sub=(h ₁₂, h ₁₃, h ₁₄, h ₁₅).Equivalent channel submatrix

$H_4=\left[\begin{array}{cccc}{h}_{11}& h_{12}& h_{13}& h_{14}\\ h_{12}^{*}& -{\mathrm{<figure-callout\; id="11"\; label="h"\; filenames="HDA0000471402440000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{11}^{*}& h_{14}^{*}& -h_{13}^{*}\\ h_{13}^{*}& h_{14}^{*}& -{\mathrm{<figure-callout\; id="11"\; label="h"\; filenames="HDA0000471402440000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{11}^{*}& -h_{12}^{*}\\ h_{14}& {-h}_{13}& -h_{12}& {\mathrm{<figure-callout\; id="11"\; label="h"\; filenames="HDA0000471402440000011.png"\; state="\{\{state\}\}">h</figure-callout>}}_{11}\end{array}\right]$

The also the same equivalent channel submatrix that obtains successively of other three kinds of antenna combinations in ergodic process.

S302: equivalent channel submatrix is carried out to QR decomposition.Obtain unitary matrice Q and upper triangular matrix R.R is as shown in S4.Right

both sides, with the conjugate transpose of taking advantage of Q, obtain

S401: order

? utilize the mode of traversal constellation point to obtain solution symbol

when symbol detection then, deduct successively the interference of the symbol having detected and utilize traversal mode to obtain solution symbol.Last solution vector

in this example, have antenna compound mode in 4, therefore obtain 4 solution vectors.

S501: respectively to the t obtaining a solution vector compute euclidian distances,

this norm of not Luo Beini crow square.Because the combination to t kind transmitting antenna travels through, so there be t Euclidean distance value.Choose solution vector corresponding to wherein minimum value and send new number as last estimation, the antenna combination that its corresponding emitting antenna combination is activated as transmitting terminal simultaneously.In this example, there are 4 kinds of antenna combinations, have 4 Euclidean distance values.Minimum value wherein must be second value, i.e. Euclidean distance value corresponding to the second emitting antenna combination.

Claims (2)

1. QR decomposes a detection method, it is characterized in that, comprises the following steps:

The mapping table one by one of S1, setting emitting antenna combination and bit, wherein, transmission antenna group is combined into adjacent E transmitting antenna composition, the compound mode of total t group antenna;

The reception signal of S2, receiver is for being N _r× 1 column vector y=HX+n=H _subx _e+ n _sub, wherein, y=(y ₁, y ₂, y ₃..., y _e), E>=3 and E are natural number, N _rfor reception antenna number, the N that H is mimo system _r× N _tchannel matrix, X is the N of the spatial modulation system transmitter of being combined with quasi-orthogonal space time block code _t× E transmitted signal, X _efor QOSTBC encoder matrix, in X, the submatrix of the capable formation of non-zero is X _e, H _subfor the antenna combined index that is activated corresponds to the channel submatrix of the respective column index in channel matrix H, n is that average is that 0 variance is σ ²additive white Gaussian noise;

When S3, receiving terminal detect, for each possible antenna combination, correspondence solves detected symbol and calculates corresponding Euclidean distance respectively, comprising:

When S31, detection, utilize equivalent channel matrix H _e, receiving terminal is equivalent to

wherein,

$\tilde{y}=(y_1,{y_2}^{\&prime;},y_3,...,{y_E}^{\&prime;}),$ X＝(x ₁,x ₂,x ₃,...,x _E)；

S32, to equivalent channel matrix H _ecarry out QR decomposition, Q is unitary matrice, and R is upper triangular matrix, wherein Q ^hq=1;

S33, right $\tilde{y}=H_{E}X+\tilde{n}$ Both sides are with taking advantage of Q ^h, that is, $Q^H\tilde{y}=\mathrm{RX}+Q^H\tilde{n};$

S34, order

?

utilize the mode of traversal constellation point to obtain solution symbol

when symbol detection then, deduct successively the interference of the symbol having detected and utilize traversal mode to obtain solution symbol, last solution vector

S35, calculating Euclidean distance,

this norm of not Luo Beini crow square.

2. a kind of QR according to claim 1 decomposes detection method, it is characterized in that: the transmission antenna group described in S1 is combined into adjacent E transmitting antenna composition, and emitting antenna combination all can be used as one group of antenna combination being activated arbitrarily.

Images