CN101043297B - Method and system for transmitting signal in multi-antenna communication - Google Patents

Abstract

The invention discloses an emitting signal method and system in multi antenna communication. In one TTI, it adopts N sending antennas to send the signal that includes: in said TTI, it adopts at least 3 different M sending antennas combination to send the signal. The invention discloses a system of emitting signal in multi antenna communication. The project of the invention can eliminate undulation of effective Signal-to-Noise generated by the arrangement change of channel matrix, the undulation of effective Signal-to-Noise of emission signal of every data package can be decreased, and the better miss package rate can be obtained.

Description

A kind of method and system of emission signal in multi antenna communication

Technical field

The present invention relates to the communications field, relate in particular to a kind of method and system of emission signal in multi antenna communication.

Background technology

Multiple-input and multiple-output (MIMO, Muliti-Input Multi-Output) technology is meant at transmitting terminal and receiving terminal and uses a plurality of transmitting antennas and reception antenna respectively, signal transmits and receives by a plurality of antennas of transmitting terminal and receiving terminal, thereby improves each quality of services for users (bit error rate or data rate).And traditional communication system is singly to enter singly (Single-InputSingle-Output, SISO) system.Advance singly (Multiple-Input Single-Output, MI2SO) mode and advance to have more singly that (Single-InputMultiple-Output, SIMO) mode also is the part of MIMO based on transmit diversity and receive diversity more.

In the MIMO technology, use Alamouti Space-Time Block Coding transmission signals at present, to obtain diversity gain.In Alamouti Space-Time Block Coding technology, use two transmitting antennas simultaneously, transmit with mode shown in Figure 1.Can use one or more reception antenna at receiving terminal.Use two transmitting antennas simultaneously at transmitting terminal, for receiving terminal, can obtain diversity (diversity) gain of these two transmitting antennas.

(Space-Time Coding STC), abbreviates the sky time-code as to Space Time Coding.Space diversity (Diversity) gain that has a spacelike time-code to utilize mimo channel to provide in BER-SNR curve commonly used, shows as and can obtain steeper slope.Among the STC according to the difference of coded system, can be divided into STTC (Space TimeTrellisCoding) space-time grid code again, Turbo code when ST Turbo Code (Space Time TurboCode) is empty, STBC (Space Time Block Coding) Space-Time Block Coding, differential space time block code (DSTBC) or the like.The Alamouti scheme is the simple and classical example of STBC.

Empty time-code can also be used to utilizing spatial reuse to obtain bigger mimo channel capacity, and the demixing time space that proposes such as Foschini (Layered Space-Time Coding, LST).

Here suppose number of transmit antennas M=2, reception antenna number N=2, then the signal received of receiving terminal can be expressed as form:

$r=H\·a+v=\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]\left[\begin{array}{cc}{a}_1& -a_2^{*}\\ a_2& a_1^{*}\end{array}\right]+\begin{array}{}\left[\begin{array}{cc}{v}_{11}& v_{12}\\ v_{21}& v_{22}\end{array}\right]\end{array}$

The r here, the definition of H and a all is to cross over 2 symbol periods.Be first symbol period, two transmitting antennas are launched a respectively ₁And a ₂, second period is emission-a respectively then ^* ₂And a ^* ₁, and each component of H remains unchanged in 2 symbol periods.The Alamouti scheme is except providing space diversity gain, and another part that induces one is that its decoding is very simple, need not to carry out joint-detection, can carry out maximal possibility estimation respectively to each symbol.Here simple declaration is once established j the received signal on the reception antenna and is:

r _j1＝h _j1a ₁+h _j2a ₂+v ₁

$r_{j2}=-h_{j1}{a}_2^{*}+h_{j2}{a}_1^{*}+v_2$

According to the criterion of maximal possibility estimation, need make the following formula minimum:

$\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({|r_{j1}-h_{j1}{\hat{a}}_1-h_{j2}{\hat{a}}_2|}^2+{|r_{j2}+h_{j1}{\hat{a}}_2^{*}-h_{j2}{\hat{a}}_1^{*}|}^2)$

After wherein every expansion merges similar terms, because | r _J1| ²With | r _J2| ²With a ₁, a ₂Value irrelevant, ask for a and make the following formula minimum so can be converted into:

$[-\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(r_{j1}{h}_{j1}^{*}{\hat{a}}_1^{*}+r_{j1}^{*}{h}_{j1}{\hat{a}}_1+r_{j2}{h}_{j2}^{*}{\hat{a}}_1+r_{j2}^{*}{h}_{j2}{\hat{a}}_1^{*})+{\left|{\hat{a}}_1\right|}^2\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({\left|h_{j1}\right|}^2+{\left|h_{j2}\right|}^2)]+$

$[-\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(r_{j1}{h}_{j2}^{*}{\hat{a}}_2^{*}+r_{j1}^{*}{h}_{j2}{\hat{a}}_2-r_{j2}{h}_{j1}^{*}{\hat{a}}_2-r_{j2}^{*}{h}_{j1}{\hat{a}}_2^{*})+{\left|{\hat{a}}_2\right|}^2\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({\left|h_{j1}\right|}^2+{\left|h_{j2}\right|}^2)]$

Be not difficult to find out, this formula first row only with a ₁Relevant, second the row only with a ₂Relevant, so can detect respectively, this just makes and adopts maximal possibility estimation to become possibility, further simplifies to obtain a ₁, a ₂Discriminant be respectively

a ₁: make ${\left|\right[\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(r_{j1}{h}_{j1}^{*}+r_{j2}^{*}{h}_{j2})]-{\hat{a}}_1|}^2+(-1+\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({\left|h_{j1}\right|}^2+{\left|h_{j2}\right|}^2)){\left|{\hat{a}}_1\right|}^2$ Minimum;

a ₂: make ${\left|\right[\underset{j=1}{\overset{N}{\mathrm{\Σ}}}(r_{j1}{h}_{j2}^{*}+r_{j2}^{*}{h}_{j1})]-{\hat{a}}_2|}^2+(-1+\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({\left|h_{j1}\right|}^2+{\left|h_{j2}\right|}^2)){\left|{\hat{a}}_2\right|}^2$ Minimum;

This two discriminants and a ₁, a ₂Modulation system irrelevant, so modulation that can be in different ways, if the PSK modulation because the each point range value is the same on the planisphere, then can further be ignored for back one of two discriminants, it will be more simple detecting.

Detect a ₁, a ₂After, also can obtain the signal to noise ratio of each symbol correspondence respectively:

${\mathrm{SINR}}_i=\frac{\left(\underset{j=1}{\overset{N}{\mathrm{\Σ}}}({\left|h_{j1}\right|}^2+{\left|h_{j2}\right|}^2)\right)\·({\left|a_i\right|}^2/M)}{{\mathrm{\σ}}^2}$

As can be seen, obtain a ₁, a ₂Method come down to a kind of hard decision.

Same principle is found out easily, under the situation of reception antenna number N=1, and the signal to noise ratio of each symbol correspondence:

${\mathrm{SINR}}_i=\frac{({\left|h_{11}\right|}^2+{\left|h_{12}\right|}^2)\·({\left|a_i\right|}^2/M)}{{\mathrm{\σ}}^2}.$

In the prior art, a kind of scheme of the Alamouti of use Space-Time Block Coding transmission signals is arranged, be used for open loop (Open Loop) mimo system.This scheme is used 4 transmitting antennas simultaneously, and the number of reception antenna can be 1,2 or 4.The employed MIMO pattern of this scheme is:

$A^{\′}=\left[\begin{array}{cccc}{s}_i& s_{i+1}& 0& 0\\ -s_{i+1}^{*}& s_i^{*}& 0& 0\\ 0& 0& s_{i+2}& s_{i+3}\\ 0& 0& -s_{i+3}^{*}& s_{i+2}^{*}\end{array}\right]$

Above matrix has 4 row, 4 row, and these 4 row are corresponding with 4 transmitting antennas, corresponding 1 the different transmitting antenna of per 1 row.4 row of above matrix are corresponding on time-domain, perhaps on frequency domain, and the perhaps continuous point of 4 on time and frequency domain.

If is transmit antenna number transmitting antenna 1,2,3,4.Can see in this scheme two symbols of emission (symbol) vector [s on transmitting antenna 1,2 _is _I+1] and [s _I+1 ^*s _i ^*], on transmitting antenna 3,4, launch two symbolic vector [s then _I+2s _I+3] and [s _I+3 ^*s _I+2 ^*].Two symbols (symbol) of emission vector [s on the transmitting antenna 1,2 _is _I+1] and [s _I+1 ^*s _i ^*] form one group of Alamouti Space-Time Block Coding, and two symbolic vector [s of emission on the transmitting antenna 3,4 _I+2s _I+3] and [s _I+3 ^*s _I+2 ^*] form another group Alamouti Space-Time Block Coding.

In the such scheme, the Alamouti Space-Time Block Coding is generally used in open loop (Open Loop) mimo system.In open loop (Open Loop) mimo system, transmitting terminal is only known the long-time statistical characteristic of channel, do not know the channel situation of current time, thereby can't use adaptive modulation and coding scheme (Adaptive modulation and coding schemes) to select more excellent modulation and channel coding schemes (The modulation and channel coding scheme), and can only use fixing modulation and channel coding schemes according to current channel situation.And when modulation with after channel coding schemes is fixed up, the packet (data block) of a common described modulation of employing and channel coding schemes transmits in a TTI (TransmissionTime Interval is a Transmission Time Interval).Because the variation of channel situation, the channel situation difference of each packet correspondence, corresponding receiving terminal received signal to noise ratio is also different, thus the Packet Error Ratio of each packet that is transmitted also will change thereupon.The target of system design is to reduce average Packet Error Ratio, the i.e. average of the Packet Error Ratio of a plurality of packets.

Under the identical situation of the average of the received signal to noise ratio of a plurality of packets, the variance of the received signal to noise ratio of a plurality of packets is more little to be that the fluctuation of received signal to noise ratio of each packet is more little, and then the average of the Packet Error Ratio of a plurality of packets is more little.2003 meeting " Information, Communications and Signal Processing " on paper " On interference cancellation ordering of V-BLAST detectors " has provided the simulation result of supporting this conclusion.

The motion R1-030777 of 3GPP also points out in " Link Error Prediction for E-DCH ", under the identical situation of the average signal-to-noise ratio of each frame (frame), compares with the bigger channel of fluctuation, and the less channel that fluctuates has better frame error rate performance.Thereby this motion is pointed out, compares with Quick-Change channel, additive white Gaussian noise (AWGN) channel and become channel slowly better frame error rate performance is arranged.Described frame error rate be equivalent to the Packet Error Ratio that we discuss, and the frame of mentioning in this motion (frame) also is to transmit usually in a TTI, similar with the packet that the present invention mentions.

In the prior art, the fluctuation of the received signal to noise ratio of a plurality of packets is bigger, can be reduced, and the average of the Packet Error Ratio of a plurality of packets is diminished.

Summary of the invention

The invention provides a kind of method of emission signal in multi antenna communication, in order to the big problem of fluctuation that solves the packet received signal to noise ratio that exists in the prior art.

The inventive method comprises:

A kind of method of emission signal in multi antenna communication is chosen at least 3 different emitting antenna combination of being made up of M transmitting antenna from N transmitting antenna;

In Transmission Time Interval TTI, adopt described at least 3 different emitting antenna combination of forming by M transmitting antenna to launch described signal, wherein,

At first symbol period, choose one group of alamouti Space-Time Block Coding of first combined transmit of forming by M transmitting antenna;

At several symbol periods subsequently, launch many group alamouti Space-Time Block Codings respectively with first combination emitting antenna combination in addition that described M transmitting antenna formed, finish until described at least 3 different emitting antenna combination traversals of forming by M transmitting antenna;

A described N transmitting antenna is virtual transmitting antenna.

Described number of transmission antennas N=4 chooses M=2 transmitting antenna and makes up.

In the described steps A, described symbol period is frequency domain cycle or time-domain cycle.

System of the present invention comprises:

A kind of system of emission signal in multi antenna communication comprises N transmitting antenna, and described system is used for choosing at least 3 different emitting antenna combination of being made up of M transmitting antenna from a described N transmitting antenna;

In Transmission Time Interval TTI, adopt described at least 3 different emitting antenna combination of forming by M transmitting antenna to launch described signal, wherein,

At first symbol period, choose one group of alamouti Space-Time Block Coding of first combined transmit of forming by M transmitting antenna;

At several symbol periods subsequently, launch many group alamouti Space-Time Block Codings respectively with first combination emitting antenna combination in addition that described M transmitting antenna formed, finish until described at least 3 different emitting antenna combination traversals of forming by M transmitting antenna;

A described N transmitting antenna is virtual transmitting antenna.

Described number of transmission antennas N=4 chooses M=2 transmitting antenna and makes up.

In the described steps A, described symbol period is frequency domain cycle or time-domain cycle.

Beneficial effect of the present invention is as follows:

Method of the present invention can be eliminated the every arrangement of channel matrix and change the fluctuation of the value of the effective signal-to-noise ratio that is caused, thereby reduce the fluctuation of the effective signal-to-noise ratio of each packet, obtains better Packet Error Ratio performance.

In addition, the present invention program, each symbol period in a TTI travels through all each different emitting antenna combination, can reduce the interference to other user like this, promptly reduces flash light effect " flashlighteffect ".

Description of drawings

Fig. 1 is the schematic diagram that uses two transmission antennas transmit Alamouti Space-Time Block Codings in the prior art;

Fig. 2 is the present invention program one a schematic flow sheet;

Fig. 3 is a system configuration schematic diagram of the present invention.

Embodiment

Below in conjunction with Figure of description the specific embodiment of the present invention is described.

According to record in the aforementioned prior art one as can be known,, in a TTI, in adjacent two symbol periods, transmit as one group, launch one group of Alamouti Space-Time Block Coding by two transmitting antennas when when transmitting terminal uses multiple transmit antennas.We can be two adjacent symbol periods of one group of Alamouti Space-Time Block Coding of emission, be called an Alamouti Space-Time Block Coding cycle, two two adjacent symbol periods in the above-mentioned Alamouti Space-Time Block Coding cycle, can be adjacent on time-domain, perhaps also can be adjacent on frequency domain.

Like this, prior art can be expressed as, and when transmitting terminal uses multiple transmit antennas, an Alamouti Space-Time Block Coding cycle, is transmitted as one group by two transmitting antennas; And in the next Alamouti Space-Time Block Coding cycle, being re-used as one group with two other transmitting antenna all inequality transmits, like this, be changeless in fact as one group of two transmitting antenna that transmit, the present invention changes to some extent to such scheme.

When carrying out the signal emission as transmitting antenna, to use the combination of a M transmitting antenna to send signal, total so total C in each Alamouti Space-Time Block Coding cycle with N antenna _N ^MIndividual compound mode can be used.The present invention is to this C _N ^MIndividual compound mode is applied in a flexible way.

As shown in Figure 2, comprise the steps:

S11, in some Alamouti Space-Time Block Coding cycles of beginning, choose first group of alamouti Space-Time Block Coding of combined transmit of some M antenna;

In these Alamouti Space-Time Block Coding cycles, according to the demand of transmitting, choose the combination of some M transmitting antenna, launch first group of alamouti Space-Time Block Coding, this M transmitting antenna can be (antenna 1 according to numbering ... antenna M), M can value be 2 in general multi-antenna emission case.

The above-mentioned Alamouti Space-Time Block Coding cycle can be time-domain cycle or frequency domain cycle.

S12, in several Alamouti Space-Time Block Coding cycles subsequently, with the C beyond first combination of this M transmitting antenna of using among the step S11 _N ^M-1 emitting antenna combination is launched first group of alamouti Space-Time Block Coding respectively;

Among the step S12, in the combination of M transmitting antenna of an above-mentioned N transmitting antenna, remove compound mode among the step S11, promptly remove and be numbered (transmitting antenna 1 ... transmitting antenna M) combination of any one M transmitting antenna after the compound mode, the transmitting antenna that uses in this combination can comprise (the transmitting antenna of choosing among the step S11 1 that is numbered ... transmitting antenna M) one or more in the transmitting antenna, but can not be identical.

S13, travel through all C _N ^MAfter-1 emitting antenna combination, return step S11.

With step S12 same treatment, guarantee C _N ^MThe signal emission has all been carried out in each combination in-1 emitting antenna combination.

By step S11-S13, can be so that the C of all transmitting antennas _N ^MIndividual combination has all participated in emission, like this, can eliminate the fluctuation of the value of effective signal-to-noise ratio, thereby reduce the fluctuation of the effective signal-to-noise ratio of each packet, obtains better Packet Error Ratio performance.

In addition, the present invention program, each symbol period in a TTI travels through all each different emitting antenna combination, can reduce the interference to other user like this, promptly reduces flash light effect " flashlighteffect ".Its principle is as described in the motion R1-050912 " MIMO proposalfor MIMO-WCDMA evaluation " that is submitted to by certain company among the 3GPP.In single codeword (SCW) pattern of this motion, at transmitting terminal 4 virtual-antennas are arranged, and some TTI only use 2 virtual-antennas wherein to carry out under the situation of spatial reuse, this proposals suggest each symbol period in a TTI travels through all C ₄ ²Individual different virtual emitting antenna combination is to reduce flash light effect " flashlight effect ", this is identical with way of the present invention, thus way of the present invention also can reach the minimizing flash light effect " flashlight effect " and effect.

The transmitting antenna of indication of the present invention can be a physical antenna, also can be the virtual-antenna described in the above-mentioned motion.

In the such scheme, in N antenna, choose M antenna, total C _N ^MPlant compound mode.In several Alamouti Space-Time Block Coding cycles of beginning, use this C _N ^MKind the combination in a kind of, from N antenna, choose M antenna and transmit.

The distribution in above-mentioned Alamouti Space-Time Block Coding cycle can also can be taked other modes according to the mode of mean allocation, such as hypothesis 120 symbol periods is arranged, and is example with 4 transmitting antennas, and using wherein, 2 emitting antenna combination send Space-Time Block Coding, then C ₄ ²=6 kinds of combinations can be set 20 Alamouti Space-Time Block Coding cycles so and use first kind of combination, and ensuing 20 Alamouti Space-Time Block Coding cycles are used second kind of combination ...Optimum situation is exactly in 120 Alamouti Space-Time Block Coding cycles, and 6 kinds of combinations are all used, and the Alamouti Space-Time Block Coding cycle that each combination takies is identical.But,, also can obtain gain if only use wherein 5 kinds of combinations.6 kinds of combinations are for example arranged in the such scheme, the emitting antenna combination of use be emitting antenna combination 1,2,1,2,1,2,3,4,5 successively, just used 5 kinds of combinations wherein, also reached the effect of obtaining gain.

Be that example is carried out the scheme explanation with 4 transmitting antennas below.

For convenience of description, the present invention adopts matrix form to describe to the transmission antennas transmit signal, and the present invention adopts the MIMO pattern to be:

$A^{\′}1=\left[\begin{array}{cccc}{s}_i& s_{i+1}& 0& 0\\ -s_{i+1}^{*}& s_i^{*}& 0& 0\\ 0& 0& s_{i+2}& s_{i+3}\\ 0& 0& -s_{i+3}^{*}& s_{i+2}^{*}\\ s_{i+4}& 0& 0& s_{i+5}\\ -s_{i+5}^{*}& 0& 0& s_{i+4}^{*}\\ 0& s_{i+6}& s_{i+7}& 0\\ 0& -s_{i+7}^{*}& s_{i+6}^{*}& 0\\ 0& s_{i+8}& 0& s_{i+9}\\ 0& -s_{i+9}^{*}& 0& s_{i+8}^{*}\\ s_{i+10}& 0& s_{i+11}& 0\\ -s_{i+11}^{*}& 0& s_{i+10}^{*}& 0\end{array}\right]$

Above matrix has 12 row, 4 row, and these 4 row are corresponding with 4 transmitting antennas, corresponding 1 the different transmitting antenna of per 1 row, and number consecutively is transmitting antenna 1, transmitting antenna 2, transmitting antenna 3 and transmitting antenna 4.The row of above matrix is corresponding on time-domain, perhaps on frequency domain, the perhaps continuous point of 12 on time and frequency domain, two continuous points are formed an Alamouti Space-Time Block Coding cycle, then these 12 continuous some difference corresponding A lamouti Space-Time Block Coding cycle 1, Alamouti Space-Time Block Coding cycles 2 ... the Alamouti Space-Time Block Coding cycle 6.

In the such scheme,, adopt the combination of transmitting antenna 1 and transmitting antenna 2 to send signal in the Alamouti Space-Time Block Coding cycle 1; In the Alamouti Space-Time Block Coding cycle 2, use the combination of transmitting antenna 3 and transmitting antenna 4 to send signal; In the Alamouti Space-Time Block Coding cycle 3, use the combination of transmitting antenna 1 and transmitting antenna 4 to send signal; Use the combination of transmitting antenna 2 and transmitting antenna 3 to send signal in the Alamouti Space-Time Block Coding cycle 4; Use the combination of transmitting antenna 2 and transmitting antenna 4 to send signal in the Alamouti Space-Time Block Coding cycle 5; Use the combination of transmitting antenna 1 and transmitting antenna 3 to send signal in the Alamouti Space-Time Block Coding cycle 6.

In the such scheme, suppose the situation of reception antenna number N=1.Then corresponding channel matrix H=[h ₁₁h ₁₂h ₁₃h ₁₄], be abbreviated as H=[h ₁h ₂h ₃h ₄].

When the MIMO pattern of using is:

$A^{\′}=\left[\begin{array}{cccc}{s}_i& s_{i+1}& 0& 0\\ -s_{i+1}^{*}& s_i^{*}& 0& 0\\ 0& 0& s_{i+2}& s_{i+3}\\ 0& 0& {-s}_{i+3}^{*}& s_{i+2}^{*}\end{array}\right]$

It is the combined transmit signal that the Alamouti Space-Time Block Coding cycle 1 uses transmitting antenna 1 and transmitting antenna 2, the ensuing Alamouti Space-Time Block Coding cycle 2 uses the combination of transmitting antenna 3 and transmitting antenna 4 to send signal, the emitting antenna combination mode that repeats these two cycles then transmits, then under these two kinds of emitting antenna combination, the signal to noise ratio of each symbol correspondence is:

${\mathrm{SINR}}_{12}=\frac{({\left|h_1\right|}^2+{\left|h_2\right|}^2)\·({\left|a\right|}^2/2)}{{\mathrm{\σ}}^2}$

${\mathrm{SINR}}_{34}=\frac{({\left|h_3\right|}^2+{\left|h_4\right|}^2)\·({\left|a\right|}^2/2)}{{\mathrm{\σ}}^2}$

Allow $\mathrm{\β}=\frac{({\left|a\right|}^2/2)}{{\mathrm{\σ}}^2}$ The expression constant, then following formula can be abbreviated as:

SINRa(1)＝SINR ₁₂＝β(|h ₁| ²+|h ₂| ²)

SINRa(2)＝SINR ₃₄＝β(|h ₃| ²+|h ₄| ²)

When the MIMO pattern of using is A ' 1, the Alamouti Space-Time Block Coding cycle 1 is used same emitting antenna combination, change in next Alamouti Space-Time Block Coding cycle emitting antenna combination then, 6 kinds of emitting antenna combination of Shi Yonging are respectively transmitting antenna 1 and transmitting antenna 2 successively, transmitting antenna 3 and transmitting antenna 4, transmitting antenna 1 and transmitting antenna 4, transmitting antenna 2 and transmitting antenna 3, transmitting antenna 2 and transmitting antenna 4, transmitting antenna 1 and transmitting antenna 3.Then corresponding received signal to noise ratio is respectively under these 6 kinds of combination of antennas:

SINRb(1)＝SINR ₁₂＝β(|h ₁| ²+|h ₂| ²)

SINRb(2)＝SINR ₁₃＝β(|h ₁| ²+|h ₃| ²)

SINRb(3)＝SINR ₁₄＝β(|h ₁| ²+|h ₄| ²)

SINRb(4)＝SINR ₂₃＝β(|h ₂| ²+|h ₃| ²)

SINRb(5)＝SINR ₂₄＝β(|h ₂| ²+|h ₄| ²)

SINRb(6)＝SINR ₃₄＝β(|h ₃| ²+|h ₄| ²)

Suppose that a packet has 120 symbols, then in that the MIMO Mode A ' down, the SINR of 60 symbols is SINR ₁₂, the SINR of other 60 symbols is SINR ₃₄And in that MIMO Mode A 1 ' down, 120 symbols can be divided into every group of 6 groups that 20 symbols are arranged, each SINR that organizes internal symbol is SINRb (i) successively, i=1, and 2 ..., 6.

In a packet, the received signal to noise ratio of each symbol is not necessarily identical, calculates the Packet Error Ratio of this packet, needs to consider the effective signal-to-noise ratio (effective SNIR) of this packet.The motion R1-050912 of 3GPP, " MIMO proposal for MIMO-WCDMA evaluation " in provided under the situation of difference of the received signal to noise ratio of considering each symbol in a packet, calculate the method for effective signal-to-noise ratio.The difference of the received signal to noise ratio of each symbol in the described packet can influence the decoding performance of turbo decoder, calculates the method for effective signal-to-noise ratio and must consider this point.A kind of method of calculating effective signal-to-noise ratio that provides in this motion is to use convex surface scale (the convex metric), uses the convex surface scale, then the effective signal-to-noise ratio γ of certain packet _EffObtain in the following manner:

${\mathrm{\γ}}_{\mathrm{eff}}=\frac{2^{\stackrel{\‾}{\mathrm{\γ}}}-1}{Q},$ Wherein $\stackrel{\‾}{\mathrm{\γ}}=\frac{1}{N}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\log }_2(1+Q\·{\mathrm{\γ}}_n),$

Here, γ _nIt is the received signal to noise ratio of each symbol in this packet, Q is penalty factor (apenalty factor), is used for the adverse effect that simulation brings because of factor such as non-Gauss modulation (non-Gaussian modulation), actual encoding rate, channel estimation errors and channel variation.

According to top narration, see easily, when the MIMO pattern of using be prior art the time, the effective signal-to-noise ratio γ of a packet _EffBe:

${\mathrm{\γ}}_{\mathrm{eff}\_0}=\frac{2^{{\stackrel{\‾}{\mathrm{\γ}}}_0}-1}{Q},$ Wherein ${\stackrel{\‾}{\mathrm{\γ}}}_0=\frac{1}{2}\underset{n=1}{\overset{2}{\mathrm{\Σ}}}{\log }_2(1+Q\·\mathrm{SINRa}\left(i\right)),$

And as the MIMO pattern of using when being of the present invention, the effective signal-to-noise ratio γ of a packet _EffBe ${\mathrm{\γ}}_{\mathrm{eff}\_1}=\frac{2^{{\stackrel{\‾}{\mathrm{\γ}}}_1}-1}{Q},$ Wherein ${\stackrel{\‾}{\mathrm{\γ}}}_1=\frac{1}{6}\underset{n=1}{\overset{6}{\mathrm{\Σ}}}{\log }_2(1+Q\·\mathrm{SINRb}\left(i\right)).$

Our emulation 500,000 packets of transmission respectively in 500,000 TTI, obtain γ _{Eff_0}(i) and γ _{Eff_1}(i), i=1,2 ..., 5 * 10 ⁵Simulation result shows, γ _{Eff_0}(i) and γ _{Eff_1}The difference of average (i) is 0.8%, can think that the two equates in error range, and γ _{Eff_0}(i) variance ratio γ _{Eff_1}(i) variance is big by 7%.Repeatedly emulation has all confirmed this conclusion.

Why γ also can be described in theory _{Eff_0}(i) variance is always than γ _{Eff_1}(i) variance is big.Find out easily, if exchange channel matrix H=[h ₁h ₂h ₃h ₄] every, the value of SINRa (1) and SINRa (2) all will change so, thereby With effective signal-to-noise ratio γ _{Eff_0}Value change; But, exchange channel matrix H=[h ₁h ₂h ₃h ₄] every, the new SINRb (i) that obtains (i=1,2 ..., 6) 6 values, compare with 6 values of exchange channel matrix before every, the change that only puts in order, 6 values itself are without any change, so With effective signal-to-noise ratio γ _{Eff_1}Value can not change.Generally speaking, scheme one can be eliminated the every arrangement of channel matrix and change the fluctuation of the value of the effective signal-to-noise ratio that is caused, thereby reduces the fluctuation of the effective signal-to-noise ratio of each packet, obtains better Packet Error Ratio performance.

As shown in Figure 3, be the system configuration schematic diagram of emission signal in multi antenna communication of the present invention, as seen from the figure, it comprises a plurality of transmitting antennas, on the basis of the above, increases:

First emitting antenna combination is chosen unit 101, is used for emitting antenna combination traveled through choosing, and by first emitting antenna combination that is selected first signal is launched;

Transmitting antenna in this system can be the physical transmit antenna, also can be virtual transmitting antenna.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (4)

1. the method for an emission signal in multi antenna communication is characterized in that, comprising:

From N transmitting antenna, choose at least 3 different emitting antenna combination of forming by M transmitting antenna;

In Transmission Time Interval TTI, adopt described at least 3 different emitting antenna combination of forming by M transmitting antenna to launch described signal, wherein,

At first symbol period, choose one group of alamouti Space-Time Block Coding of first combined transmit of forming by M transmitting antenna;

At several symbol periods subsequently, launch many group alamouti Space-Time Block Codings respectively with first combination emitting antenna combination in addition that described M transmitting antenna formed, finish until described at least 3 different emitting antenna combination traversals of forming by M transmitting antenna;

A described N transmitting antenna is virtual transmitting antenna.

2. the method for claim 1 is characterized in that, described number of transmission antennas N=4 chooses M=2 transmitting antenna and makes up.

3. the method for claim 1 is characterized in that, described symbol period is frequency domain cycle or time-domain cycle.

4. the system of an emission signal in multi antenna communication comprises N transmitting antenna, it is characterized in that, described system is used for choosing at least 3 different emitting antenna combination of being made up of M transmitting antenna from a described N transmitting antenna;

In Transmission Time Interval TTI, adopt described at least 3 different emitting antenna combination of forming by M transmitting antenna to launch described signal, wherein,

At first symbol period, choose one group of alamouti Space-Time Block Coding of first combined transmit of forming by M transmitting antenna;

At several symbol periods subsequently, launch many group alamouti Space-Time Block Codings respectively with first combination emitting antenna combination in addition that described M transmitting antenna formed, finish until described at least 3 different emitting antenna combination traversals of forming by M transmitting antenna; A described N transmitting antenna is virtual transmitting antenna.

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