CN101048993A - Coded-bit scrambling for multi-stream communication in a MIMO channel - Google Patents

Abstract

In one embodiment, a multi-input/multi-output system ( 100 ) includes a receiver ( 104 ), processor, coded bit scrambler ( 114 ), coded bit descrambler ( 130 ), and transmitter ( 102 ). The receiver ( 104 ) generates demodulated symbol streams corresponding to a received signal. The processor generates coded bit sequences from source bit streams when operating in a transmit mode and bit log-likelihood ratio sequences from the information bit streams when operating in a receive mode. The coded bit scrambler ( 114 ) scrambles the coded bit sequences to generate scrambled bit streams when in the transmit mode. The coded bit descrambler ( 130 ) descrambles the log-likelihood ratio sequences by a real-valued descrambling sequence when operating in the receive mode, and also removes the effect of a scrambling sequence. The transmitter ( 102 ) generates a transmit signal corresponding to the scrambled bit streams.

Description

The coded-bit scrambling that is used for the multi-stream communication of mimo channel

Priority according to 35U.S.C. § 119 requirements

The title that present patent application requires on August 27th, 2004 to submit to be " CODED BITSCRAMBLING FOR MULTI-STREAM TRANSMISSION IN MIMOCHANNEL " the 60/605th, No. 183 provisional application, the title of submitting on September 30th, 2004 be " CODED BIT SCRAMBLING FOR MULTI-STREAMTRANSMISSION IN MIMO CHANNEL " the 60/615th, the title of submitting in No. 567 provisional application and on October 8th, 2004 be " CODED BIT SCRAMBLING FORMULTI-STREAM TRANSMISSION IN MIMO CHANNEL " the 60/617th, the priority of asking in interim for No. 502, these applications have been transferred to its assignee, thereby it is incorporated herein by reference clearly.

Technical field

The present invention relates generally to radio communication, and more specifically relate to the many inputs-multithread transmission of exporting in (MIMO) channels in the wireless communication system more.

Background technology

Many inputs-many output (MIMO) antenna systems recent success to small part aspect wireless channel is because they can realize and transmit and receive the fact that the proportional linear capacity of number of antennas increases.For many inputs-multithread transmission of exporting in (MIMO) code division multiple access (CDMA) system, give a plurality of streams with a plurality of different walsh codes or identical walsh-code assignments usually more.A kind of code allocation strategy is from independent walsh-code assignments, shares these codes gradually along with the increase of the data rate of each stream or required number of codes then.Yet final, identical code will be assigned to all stream, so that realize the power-carrying that mimo system can provide.In the arrowband mimo system that can not carry out the bandwidth expansion, do not covering a plurality of streams of transmission under the situation of carrying out any channel separation usually by walsh code.

Depend on moving of travelling carriage, the channel coefficient vector of each data flow in the mimo system will have various instantaneous realizations.Coefficient vector may be almost mutually orthogonal a moment, and they may have very approaching value or have very high instantaneous correlation in next moment.When the channel coefficient vector of a plurality of streams become near the time, each fails to be convened for lack of a quorum and disturbs other stream.Under extreme case, when the channel coefficient vector of a plurality of streams was got much at one value, the decoder of each stream can suffer stream that needs and the competition of disturbing the decoding path metric between the stream.If travelling carriage is seen the very strong sight line from the base station (LOS) signal, so this extreme case can often take place, in this case, and the Ricean matrix channel that mimo channel becomes and approaches the AWGN matrix channel or have the very high Ricean factor.Therefore, need to overcome the communication system and the method for these problems in the art.

Summary of the invention

Embodiment disclosed herein carries out scramble by the coded-bit to each stream, with prevent channel coefficient vector at a plurality of streams become comparison near or when relevant the decoding performance of mimo system worsen, and solved above-mentioned needs.In one embodiment, different scrambling codes is taken on the coded-bit of each stream, worsened with the decoding performance that prevents mimo system when the channel coefficient vector of a plurality of streams becomes approaching or relevant.It is invalid random code word that this competition code word that interference is flowed converts to from the viewpoint of the decoder of required stream.An embodiment provides the scramble of each stream to conciliate scramble.

Carry out scramble (usually occurring in the reflector) by the coded-bit to each stream and conciliate scramble (usually occurring in the receiver), the decoder of each stream has been avoided codeword collisions.During separating scramble, the potential competition code word of interference stream has lost the reasonability as candidate codewords, and is converted into non-hazardous random code word.In many cases, the path metric that can not compete to the candidate codewords of the hypothesis in the decoder of random code word.The effect of different interlace modes or different perforation and repeat pattern (for example, redundancy versions) is similar with different scrambles.

An embodiment comprises a kind of equipment, this equipment comprises and is used for the multiple source bit stream is encoded to produce the encoder of a plurality of coded bit streams, the scramblers that are used for adopting different configurations carry out the bit-stream processor of scramble with the bit stream that produces a plurality of different scrambles to each of above-mentioned coded bit stream, and the mapper that is used for the bit groups of the bit stream of above-mentioned a plurality of different scrambles is mapped to transmission symbol.

Another embodiment comprises a kind of equipment, this equipment comprises and is used for the multiple source bit stream is encoded to produce the encoder of a plurality of coded bit streams, be used for adopting different interlace modes that each of coded bit stream interweaved with the bit-stream processor of the bit stream that produces a plurality of different interleavings, and the mapper that is used for the bit groups of the bit stream of above-mentioned a plurality of different interleavings is mapped to transmission symbol.

Another embodiment comprises a kind of equipment, this equipment comprises and is used for the multiple source bit stream is encoded to produce the encoder of a plurality of coded bit streams, be used on each coded bit stream adopting different perforation or repeat pattern and each of coded bit stream carried out rate-matched producing the bit-stream processor of a plurality of different bit streams, and the mapper that is used for the bit groups of above-mentioned a plurality of different bit streams is mapped to transmission symbol.

Another embodiment comprises a kind of equipment, this equipment comprises that the symbol translation that is used for receiving becomes bit groups to produce the de-mapping device of a plurality of reception bit streams, be used for the different scramble algorithm application of separating are received bit stream in each and separate the bit-stream processor of the bit stream of scramble to produce a plurality of differences, and the bit stream that is used for above-mentioned difference is separated scramble is decoded to produce the decoder of a plurality of decoding bit streams.

Another embodiment comprises a kind of equipment, this equipment comprises that the symbol translation that is used for receiving becomes bit groups to produce the de-mapping device of a plurality of reception bit streams, be used for that different deinterleaving patterns is applied to each and receive the bit-stream processor of bit stream, and be used for the bit stream of above-mentioned different deinterleavings is decoded to produce the decoder of a plurality of decoding bit streams with the bit stream that produces a plurality of different deinterleavings.

Another embodiment comprises a kind of equipment, this equipment comprises that the symbol translation that is used for receiving becomes bit groups to produce the de-mapping device of a plurality of reception bit streams, be used for the different hole patterns of separating are applied to each and receive bit stream and separate the bit-stream processor of the bit stream of perforation to produce a plurality of differences, and the bit stream that is used for above-mentioned difference is separated perforation is decoded to produce the decoder of a plurality of decoding bit streams.

Another embodiment comprises a kind of being used in many input-multi-output communication system method of transmitting information.This method comprises encodes to produce a plurality of coded bit streams to the multiple source bit stream, with the scrambler of difference configuration in the above-mentioned coded bit stream each carried out scramble producing the bit stream of a plurality of different scrambles, and the bit groups of the bit stream of above-mentioned a plurality of different scrambles is mapped in the transmission symbol.

Another embodiment comprises a kind of being used in many input-multi-output communication system method of transmitting information.This method comprises encodes to produce a plurality of coded bit streams to the multiple source bit stream, adopt different interlace modes that in the coded bit stream each interweaved producing the bit stream of a plurality of different interleavings, and the bit groups of the bit stream of above-mentioned a plurality of different interleavings is mapped in the transmission symbol.

Another embodiment comprises a kind of being used in many input-multi-output communication system method of transmitting information.This method comprises encodes to produce a plurality of coded bit streams to the multiple source bit stream, on each coded bit stream, adopt different perforation or repeat pattern and in the coded bit stream each carried out rate-matched producing a plurality of different bit streams, and the bit groups of above-mentioned a plurality of different bit streams is mapped in the transmission symbol.

Another embodiment comprises a kind of method that is used for the information that receives at communicator.This method comprises that the symbol translation that will receive becomes bit groups to produce a plurality of reception bit streams, the different scramble algorithm application of separating are received bit stream in each and separate the bit stream of scramble to produce a plurality of differences, and the bit stream that above-mentioned difference is separated scramble is decoded to produce a plurality of decoding bit streams.

Another embodiment comprises a kind of method that is used for the information that receives at communicator.This method comprises that the symbol translation that will receive becomes bit groups to produce a plurality of reception bit streams, different deinterleaving patterns is applied to each receives bit stream producing the bit stream of a plurality of different deinterleavings, and the bit stream of above-mentioned different deinterleavings is decoded to produce a plurality of decoding bit streams.

Another embodiment comprises a kind of method that is used for the information that receives at communicator.This method comprises that the symbol translation that will receive becomes bit groups to produce a plurality of reception bit streams, the different hole patterns of separating are applied to each and receive bit stream and separate the bit stream of perforation to produce a plurality of differences, and the bit stream that above-mentioned difference is separated perforation is decoded to produce a plurality of decoding bit streams.

Description of drawings

Figure 1A is based on the block diagram of an embodiment of the many yards cdma systems of MIMO of independent coding and spatial reuse;

Figure 1B is based on the block diagram of another embodiment of the many yards cdma systems of MIMO of independent coding and spatial reuse;

Fig. 1 C is based on the block diagram of an embodiment of the MIMO ofdm system of independent coding and spatial reuse;

Fig. 2 is the throughput performance of 2 * 2MIMO system and the relation line figure of ρ T, wherein Ec=Ior=-3dB and ρ R=0;

Fig. 3 is PER performance and the relation line figure of Ec/Ior under ρ T situation of change, the wherein G=10dB and the ρ R=0 of 4 * 4MIMO system;

Fig. 4 is PER performance and the relation line figure of Ec/Ior under ρ R situation of change, the wherein G=10dB and the ρ T=0 of 4 * 4MIMO system;

Fig. 5 is the relation line figure of the PER performance and the efficient coding rate of 4 * 4MIMO system, G=10dB wherein, Ec=Ior=-3dB, and ρ R=0;

Fig. 6 is the flow chart of method of transmitting information in many input/multiple output systems; And

Fig. 7 is the flow chart that receives the method for information in many input/multiple output systems.

Embodiment

In one embodiment, by the many inputs-processing independently of code word quilt, scramble or randomizations of exporting the parallel data stream of a plurality of antennas emissions in (MIMO) wireless channels more.When the channel coefficient vector of two or more parallel streams become near or when relevant, it is invalid random code word that the code word of the interference stream that this code word scramble may be competed converts to from the viewpoint of the decoder of required stream.Hereinafter will further explain, to such an extent as to when encoding rate is enough low can use the repetition rate coupling after baseline channel coding the time, the code word scramble also can provide effective interference variance to reduce.Scramble has been improved decoding performance, particularly when mimo channel in emitter side during height correlation or when repetition rate is very high.

Figure 1A and Figure 1B are based on the simplified block diagram of many yards cdma systems of MIMO 100,101 of independent coding.Although the discussion of this paper is primarily aimed at many yards cdma systems, it should be understood that whole discussion and results of property also can be applicable to common MIMO transceiver.For example, by removing expander and the Solution Expander functional blocks among Figure 1A or Figure 1B, system equipment discussed herein and method can be applicable to the narrow band transmission system, such as global system for mobile communications (GSM) and time division multiple access (TDMA) system.

In the embodiment shown in Figure 1A, mimo system 100 comprises reflector 102 and receiver 104.M source bit stream 106 is provided for encoder 108 altogether.Encoder 108 provides input to rate matchers 110.The output of rate matchers 110 is sent to interleaver 112, and interleaver 112 provides input to scrambler 114.Mapper 116 is coupled to the output of scrambler 114, and provides input to expander 118.Mapper with the bit groupings of bit stream to the transmission symbol of predetermined modulation type.The output of expander 118 is sent to transmitting antenna 120.

In the optional embodiment shown in Figure 1B, mimo system 101 also comprises reflector 102 and receiver 104.M source bit stream 106 is provided for encoder 108 altogether, and encoder 108 provides input to rate matchers 110, as among the embodiment of Figure 1A.Yet in the embodiment of Figure 1B, the output of rate matchers 110 is provided for scrambler 114, and scrambler 114 provides input to interleaver 112.The output of interleaver 112 is sent to mapper 116, and mapper 116 provides input to expander 118.With the same among Figure 1A, the output of expander 118 is sent to transmitting antenna 120.

Each independent functional blocks in the block diagram of Figure 1A-1C all is that in the art technical staff is known, and in this article will be no longer the details of its structure and function be described in detail.To have the different bit stream that is suitable for more transmitting with the characteristic of storage than original bit stream be common purpose to encoder so that original bit stream is converted to, and bit stream is translated into different bit streams.Encoder can be realized with software or hardware usually.At transmitting terminal, rate matchers 110, interleaver 112 and scrambler 114 form the bit stream treatment circuit to operating from the coded bit stream of encoder 108 together.It is known being used to carry out the bit stream perforation of rate-matched and repeating, and is known too by carrying out the bit stream rearrangement interweaving in the emission system.In various application, the function of scrambler and design also are known.One aspect of the present invention is, is to carry out on each that leaving in a different manner in a plurality of bit streams of encoder in the bit stream processing of carrying out between encoder and the mapper.The interleaver output of each bit stream is a series of bit groups that are called code word herein, and code word wherein depends on the content of encoder incoming bit stream.Because interleaver output typically comprises than encoder input more bits, so not all any output can at any time obtain." effectively " code word used herein or " legal " code word, be encoder, rate matchers and interleaver the cascade treatment circuit the output code word within the set of the possible output code word that can produce.The engineering noise code word is the code word outside this set.

Return with reference to Figure 1A, signal of communication is launched from transmitting antenna 120, and is received by the reception antenna 122 of another mimo system 100.Reception antenna 122 is coupled to space-time equalizer 124, and space-time equalizer 124 provides input to Solution Expander 126.Solution Expander 126 is coupled to de-mapping device 128, and de-mapping device 128 is coupled to descrambler 130.The output of descrambler 130 is coupled to deinterleaver 132.Deinterleaver 132 is coupled to rate matchers 134, and rate matchers 134 provides input to decoder 136.The output of decoder 136 comprises M decoding bit stream 138, is called as bit stream 0 in this article to M-1.

In the embodiment of Figure 1B, signal of communication is launched from transmitting antenna 120, and is received by reception antenna 122, and is the same among the embodiment with Figure 1A.Reception antenna 122 is coupled to space-time equalizer 124, and space-time equalizer 124 provides input to Solution Expander 126.Solution Expander 126 is coupled to de-mapping device 128, and de-mapping device 128 is coupled to deinterleaver 132.The output of deinterleaver 132 is coupled to descrambler 130.Descrambler 130 is coupled to rate matchers 134, and rate matchers 134 provides input to decoder 136.The output of decoder 136 comprises M decoding bit stream 138, is called as bit stream 0 in this article to M-1.

In in cdma system 100,101 any, M message bit stream 106 encoded independently by encoder 108, by rate matchers 110 repeat or perforation with coupling transmission symbol speed, and interweave in frame period by interleaver 112.Bit sequence after each interweaves depends on that by mapper 116 modulation type (for example, QPSK or 16QAM) and grouping and be mapped to the sequence of transmission symbol or constellation point, expand by the common subset of available walsh codes and the special-purpose chip scramble of reflector code by expander 118, launch by each transmitting antenna 120 then.Although distribute different walsh code subclass by the different transmitting antenna 120 of whenever giving that can use in different walsh code subclass, can reduce the decoding error rate, but in this embodiment, the common subset of walsh code is reused by at least a portion in a plurality of transmitting antennas 120.

Total transmitting power is cut apart and is assigned to each transmitting antenna 120.A plurality of streams of emission arrive N reception antenna 122 after the distortion through MIMO fading channel and additive white Gaussian noise (AWGN) vector.Suppose N 〉=M, and for simplicity, the time-varying MIMO channel has smooth fading characteristic, but they can be easy to be extended to N＜M and be the situations that frequency is selected fading channel.Channel variation in the transmission frame duration is relatively little.Space-time equalizer 124 generates the soft chip sequence of M transport stream, and Solution Expander 126 generates corresponding sequence of soft-symbols.By using soft symbol, de-mapping device 128 generates bit log-likelihood ratio (LLR) sequence, and this sequence is fed to the independent circuit of deinterleaver 132, rate matchers 134 and decoder 136, to recover a plurality of sources and courses 106.

N * M fading channel matrix is called H ≡ [h0, h1 ..., hM-1], M * 1 emission symbolic vector is called x (k) ≡ [x0 (k), x1 (k) ..., xM-1 (k)] T, and the N * 1AWGN vector that is designated as k during the symbol that obtains afterwards in de-spread (multiply each other with the space-time equalizer coefficients) calls n (k) ≡ [n0 (k), n1 (k) ..., nN-1 (k)] and T.Vector hi is N * 1 channel coefficient vector that is associated with emission symbol xi (k).De-mapping device input soft symbol yi (k) corresponding to i data flow is represented as:

$y_i\left(k\right)=w_i^H\mathrm{Hx}\left(k\right)+w_i^{H}n\left(k\right)---\left(1\right)$

$=\underset{j=0}{\overset{M-1}{\mathrm{\Σ}}}{w}_i^H{h}_j{x}_j\left(k\right)+w_i^{H}n\left(k\right)---\left(2\right)$

$=\underset{j=0}{\overset{M-1}{\mathrm{\Σ}}}{a}_{\mathrm{ij}}{x}_j\left(k\right)+v_i\left(k\right),i=\mathrm{0,1},...,M-1---\left(3\right)$

The vectorial w in N * 1 wherein _iI weight coefficient vector of expression space-time equalizer, $a_{\mathrm{ij}}\≡w_i^H{h}_j$ , and $v_i\left(k\right)\≡w_i^{H}n\left(k\right)$ 。By using linear peak signal interference-to-noise ratio (MSINR) space-time equalizer, for average modulation symbol energy E _sWith noise variance N _o, i weight vectors got following value:

$w_i={[\underset{j=0,j\≠i}{\overset{M-1}{\mathrm{\Σ}}}{E}_s{h}_j{h}_j^H+N_{o}I]}^{-1}{h}_i---\left(4\right)$

And the symbol SINR that obtains becomes:

${\mathrm{SINR}}_i=E_s{h}_i^H{[\underset{j=0,j\≠i}{\overset{M-1}{\mathrm{\Σ}}}{E}_s{h}_j{h}_j^H+N_{o}I]}^{-1}{h}_i---\left(5\right)$

When constellation size is 2 ^BThe time, de-mapping device 128 by to the conditional probability density function p of α under the β specified criteria (α | β), get

${\mathrm{\Λ}}_i^l\left(k\right)=\log \frac{p(b_i^l\left(k\right)=0|y_i\left(k\right))}{p(b_i^l\left(k\right)=1|y_i\left(k\right))}---\left(6\right)$

Generate and observed soft symbol y _i(k) l the bit b that is associated _i ^l(k) (l=0,1 ..., LLR Λ B-1) _i ^l(k).Λ _i ^l(k) be to have under the supposition of equal prior probability, pass through y in each constellation point _i(k) the noise and the Gaussian approximation of interference component calculate.

Those technical staff in present technique field should be appreciated that foregoing can be applied to various communication systems, comprise OFDM (OFDM) system, the ofdm system 103 shown in Fig. 1 C.Ofdm system 103 comprises reflector 102 and receiver 104.The receiver 102 of shown ofdm system 103 comprises many and the identical assembly of cdma system (such as above-mentioned cdma system 100,101).For example, ofdm system 103 comprises M source bit stream 106, and they are provided for encoder 108.The output of encoder 108 is sent to rate matchers 110, and rate matchers 110 is coupled to the input of interleaver 112.Interleaver 112 outputs are sent to scrambler 114, and scrambler 114 is coupled to the input of mapper 116.Should be appreciated that in this OFDM embodiment, scrambler can be positioned between the rate matchers and interleaver in the reflector, and between the deinterleaver and rate matchers in the receiver, this also is illustrated in the CDMA of Figure 1B embodiment.

Yet in ofdm system 103, the output of mapper 116 is sent to subcarrier allocator 140, and subcarrier allocator 140 receives the sub-carrier subset of distributing.The output of subcarrier allocator 140 is coupled to the input of inverse discrete Fourier transformer inverse-discrete device (IDFT) 142.IDFT 142 is coupled to Cyclic Prefix inserter 144, and the output of Cyclic Prefix inserter 144 is coupled to m transmitting antenna 120.

Ofdm system 103 adopts M antenna 122 reception information, and these antenna is coupled to the input of Cyclic Prefix arrester 146.The output of Cyclic Prefix arrester 146 is coupled to discrete Fourier transformer 148, and discrete Fourier transformer 148 is coupled to spatial equaliser 150.The output of spatial equaliser 150 is coupled to subcarrier selector 152, and subcarrier selector 152 receives the subcarrier set that distributes.The same with the arbitrary embodiment among the above-mentioned cdma system embodiment 100,101, the output of subcarrier selector 152 is coupled to de-mapping device 128, descrambler 130, deinterleaver 132, rate matchers 134 and decoder 136.

The scrambler of Figure 1A-1C and descrambler have been improved the decoding performance when the correlation between the column vector of instantaneous channel matrix and the row vector has a negative impact to decoding performance.

The data rate that the interference that worsens occurs in preceding two streams equates and preceding two column vectors (for example, h0 ≈ h1) closer to each other of channel matrix the time.When first stream of decoding { x0 (k) }, import soft symbol corresponding to the de-mapping device of first stream and become:

$y_0\left(k\right)\≈a_{00}[x_0\left(k\right)+x_1\left(k\right)]+\underset{j=2}{\overset{M-1}{\mathrm{\Σ}}}{a}_{0j}{x}_j\left(k\right)+v_0\left(k\right)---\left(7\right)$

The channel decoder 136 of first stream (after deinterleaving and rate-matched) calculates the path metric of legal candidate codewords based on the bit LLR value of observation sequence { y0 (k) } generation by adding up, and they are compared to determine the transmission information bit of first stream.When (and through rate-matched and the interweave) bit sequence behind the coding of second stream { x1 (k) } also is one of legal candidate codewords and when producing comparable path metric value for the decoding of first stream, the decoder of first stream can execution error Sequence Detection, have at least 0.5 the probability can be like this.That is to say, when corresponding channel column vectors near the time, the decoder 136 of first stream may be decoded to second stream, rather than first stream is decoded.If more than two channel coefficient vector height correlations, then wrong sequence detection probability can further increase.Since when two channel coefficient vector relatively near the time two streams reporting from receiver feedback SINR much at one, even so when reflector 102 depended on that channel status is adjusted the data rate of each stream adaptively, reflector 102 also may be selected identical transmission rate or transformat for first and second streams.

Be that two streams are selected identical transformats, make bit sequence behind the coding of second stream become competition candidate codewords in the process of first stream of decoding legally unfortunately, vice versa.If receiver 104 to the relevant information of reflector 102 send channel coefficient vectors and the SINR of each stream, then can optionally activate or not activate stream, avoid this conflict.Yet doing like this to increase feedback information volume, and will be measured and feedback delay.

Codeword competition problem occurs in transmitting antenna 120 more relevant the time more continually, because this a plurality of column vector moment that will increase channel matrix becomes approaching probability.For prevent when channel column vectors instantaneous near the time codeword competition between a plurality of streams, in an embodiment (all embodiment as shown in Figure 1), be provided with XOR (XOR) computing between the bit sequence { ci (n) } of i binary pseudorandom (PN) scrambling sequence { si (n) } of output place of the interleaver 112 in emitter side and i coding, wherein the markers of process rate-matched behind the n presentation code and the bit sequence that interweaves.Use mark k, l, B and the b of equation (6) _i ^l(k), utilize then concern n=kB+1 with $b_i^l\left(k\right)=\mathrm{ci}\left(n\right)\⊕\mathrm{si}\left(n\right),$ Wherein  represents the XOR between the binary value.

Advantageously, the scrambling sequence of a plurality of streams is independently of one another.At receiver-side, i bit LLR sequence that flows be multiply by i real-valued scrambling sequence { 1-2si (n) }, to cancel the influence of i scrambling sequence.By parallel flow being used independently scrambling sequence, from the competition code word of the channel coefficient vector that is had near the interference stream of the channel coefficient vector of required stream, major part has become random code word by scramble reconciliation scramble processing.Therefore, the decoder 136 of required stream (for example, { x0 (k) } in the equation (7)) will not select to disturb the code word of stream (for example, { x1 (k) } in the equation (7)).When efficient coding rate step-down that the ratio of the number by process rate-matched behind information bit and the coding and the bit that interweaves defines, the random code word that obtains is legal-code or the probability step-down that approaches code word.Figure 1A-1C shows coded-bit scrambling device CBS 114 in the reflector 102 and the corresponding descrambler 130 in the receiver 104.

Exist various enforceable variation to reach identical effect, comprise parallel stream is used different bit level channel interleaver patterns, perhaps can in the rate-matched process, use different perforation and repeat pattern parallel stream.In these embodiments, not necessarily need independent scrambler.

Scrambler 114 provides another the useful effect for the transmission of the multithread in the quasistatic mimo channel.Depend on the efficient coding rate, 110 pairs of channel encoders of rate matchers, 108 output bits carry out repetition or perforation.Scrambler 114 in that output place of interleaver 112 or rate matchers 110 is used produces significant the improvement to code word SINR when the repetition rate coupling takes place.For example, if the encoding rate of baseline channel encoder 108 is 1/3, and first flows and the efficient coding rate of second stream is 1/6 by chance, and then rate matchers 110 repeats the encoder 108 output bits of two streams 106 again.

When (with rate matchers 134 combination) channel decoder 136 of first stream adds up branch metric when generating the path metric of candidate codewords, corresponding interference component is added up under the state of their phase alignment with the repetition bits of second stream.The independent scramble of through-rate match bit sequence, when the signal component that repeats during by coherent accumulation, the interference component of repetition is added up under the state that their phase place is randomized, and therefore, the interference variance of path metric is reduced.Reducing in most of channel is realized of this interference variance is effective, unless the complete quadrature of channel column vectors.

In order to assess the gain in the mimo system 100, the link throughput and the frame error ratio (FER) of fixed data rate WCDMA HSDPA system compared with many antennas and linear MSINR space-time equalizer from coded-bit scrambling (CBS).In HSDPA, by (under the chip-rate of 3.84Mcps) spreading factor be 16 and the maximum number that can be used for the walsh code of transfer of data be a plurality of walsh codes of 15, data stream is expanded.The fixed subset of following emulation repeated use available walsh codes is transmitted a plurality of streams.The turbo encoder is used with baseline code rate 1/3, and is applied in rate-matched, interweaves and constellation mapping.The number of modulation symbols that each walsh code transmitted in one frame is 480, and frame duration is 2ms (7680 chip).For mimo channel, relevant rayleigh fading channel H (t) is generated by for example following formula:

$H\left(t\right)={\mathrm{<figure-callout\; id="1"\; label="C\; R"\; filenames="A20058003714800221.png,A20058003714800231.png"\; state="\{\{state\}\}">C</figure-callout>}}_R^{}{H}_0\left(t\right){\mathrm{<figure-callout\; id="1"\; label="C\; T"\; filenames="A20058003714800221.png,A20058003714800231.png"\; state="\{\{state\}\}">C</figure-callout>}}_T^{}---\left(8\right)$

C wherein _RAnd C _TBe the correlation matrix of transmitting antenna and reception antenna, its diagonal element equals 1.0, and H _o(t) element is independently plural Gaussian random process, and t is a markers.For simplicity, C _RAnd C _TOff diagonal element be configured to reality and close coefficient ρ _RAnd ρ _T, its scope is from 0.0 to 1.0.This emulation is to H _o(t) each element uses the single path Rayleigh fading process of 30km/h, and carrier frequency is 2GHz, and has supposed desirable channel and Noise Variance Estimation for the space-time equalizer.

Fig. 2 is the figure of link throughput that is used for the mimo system that has two transmitting antennas and two reception antennas of QPSK and 16QAM constellation.In Fig. 2,16QAM-CBS or QPSK-CBS indication CBS are applied to the situation of parallel transmission stream.Each antenna stream is transmitted with fixing speed, is every frame 1,250 source bit (for example, the total speed of 1.25Mbps target (target sum rate)) for QPSK, and is every frame 2,500 source bits (for example, the total speed of 2.5Mbps target) for 16QAM.The Walsh yardage of distributing is 4, and like this, for two kinds of constellations, it is about 1/3 that the efficient coding rate is, and this baseline code rate with the turbo encoder equates.Mixed automatic repeat request (HARQ) is based on and retransmits maximum is 4 the merging of catching up with.This emulation interweaves in time 6 and independently stops-the HARQ process of wait type, and the Transmission Time Interval of each process is 6 frames (for example, 100% channel utilizations).The through-put power part Ec/Ior that distributes to data service be fixed to overall transmission power 50% (for example,-3dB), and the geometry value G with the ratio definition of total AWGN power is arranged to respectively by total received signal power, is 0dB for QPSK, is 10dB for 16QAM.Fig. 2 shows at ρ _RBe 0, ρ _TThe aggregate throughput of during from 0 to 1 variation two emission streams being sued for peace.Work as ρ _TBecome greater than 0.7 o'clock, CBS has substantially improved throughput performance.Work as ρ _TBe 1.0 o'clock, conventional 16QAM mimo system can not communicate, but the system that is based on CBS still can transmit sufficient amount of information.Based on the throughput gain of the system of CBS be owing to effect that reduces of catching up with interference variance during the merging and the codeword competition between the stream prevent produce.

Fig. 3-4 has compared four FER that transmit and receive the mimo system of antenna that have when Ec/Ior changes.Geometry value G is configured to 10dB.In Fig. 3, ρ _TChange and ρ _RRemain 0.In Fig. 4, ρ _RChange and ρ _TRemain 0.In four antenna stream each all uses the QPSK constellation to transmit continuously with the fixed rate of every frame 1,250 source bit (for example, the total speed of 2.5Mbps target).The number of the walsh code that distributes is 8, and like this, the efficient coding rate is about 1/6.Therefore, the rate-matched chunk repeats most of encoder output bit twice.Because interference variance reduction capability between stream, CBS can greatly improve FER, even at ρ _TAnd ρ _RWhen equaling 0.Improvement is at ρ _TIt is bigger to become during increase, but it is not as ρ _RChange so muchly during increase.The asymmetric effect of CBS on reflector and receiver correlation can partly be explained by the codeword competition problem that takes place under the reflector correlation circumstance.

Fig. 5 shows the FER of the mimo system identical with the system studied among Fig. 3, but Ec/Ior is configured to-3dB, and G is configured to 10dB, and the Walsh yardage of distributing becomes 8 from 2, makes that the scope of efficient coding rate is from about 2/3 to about 1/6.When the baseline code rate of turbo encoder was 1/3, the rate-matched chunk was carried out when encoding rate is lower than and is higher than 1/3 respectively and is repeated and perforation.Because interference variance reduction capability, when repetition rate increased, CBS brought significant gain.In this case, efficient coding rate reduces.

As discussed above, when channel column vectors become near the time, in MIMO transmission system absolute coding and spatial reuse, exist potential problems.Two or more streams have a probability that the extreme case of instantaneous channel column vectors much at one takes place in actual channel very low, but this is in case codeword competition problem in the spatial multiplexing MIMO system takes place to cause.Independently scramble be applied to behind the coding of one or more transport stream and through the bit sequence of rate-matched, to reduce this problem.When effective encoding rate becomes when being lower than the encoding rate of baseline channel encoder, coded-bit scrambling has reduced effective variance of disturbing between stream according to the quality of decoding path metric.Also can in mimo system, realize by the performance improvement that scramble obtains based on the adaptability rate controlled.

Fig. 6 is the flow chart of method of transmitting information 600 in many input/multiple output systems.At flow path block 602, bit stream is processed, to generate sequences of code bits.At flow path block 604, generate scrambling sequence, wherein homogeneous turbulence does not generate different scrambling sequences.At flow path block 606, sequences of code bits is by scramble, to generate the bit stream of scramble.At flow path block 608, the bit stream of scramble is processed, to generate transmission bit stream.At last, at flow path block 610, transmission bit stream is transmitted.

Fig. 7 is the flow chart that receives the method 700 of information in many input/multiple output systems.At flow path block 702, receive message bit stream.At flow path block 704, message bit stream is processed, to generate bit log-likelihood ratio sequences.At flow path block 706, bit log-likelihood ratio sequences is separated scramble, with the soft bit stream of generating solution scramble.At last, at flow path block 708, the soft bit stream of separating scramble is processed, to generate decoding bit stream.

Those skilled in the art are appreciated that and can use many different technologies and technology to come expression information and signal.For example, the data of mentioning in the above-mentioned explanation, instruction, order, information, signal, bit, symbol, and chip can be expressed as voltage, electric current, electromagnetic wave, magnetic field or magnetic particle, light field or light particle or above any combination.

Those skilled in the art can also further recognize, logical block, module, circuit, method and the algorithm steps of the various examples of describing in conjunction with embodiment disclosed herein can be implemented with electronic hardware, computer software or the combination of the two.For the interchangeability of hardware and software is described, assembly, chunk, module, circuit, and the step of various examples described prevailingly according to function in the above description.This function still is that software mode is realized with hardware actually, depends on the specific application and the design constraint of whole system.The professional and technical personnel can use distinct methods to realize described function to each specific should being used for, but this realization decision should not be considered to exceed scope of the present invention.

Logical block, module and the circuit of the multiple example of describing in conjunction with embodiment disclosed herein can be with general processor, digital signal processor (DSP), application-specific integrated circuit (ASIC) (ASIC), field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or the above combination in any that is designed to carry out function described herein realize or carry out.General processor can be a microprocessor, but replacedly, processor also can be processor, controller, microcontroller or the state machine of any routine.Processor also may be implemented as the combination of calculating device, for example, and the combination of the combination of DSP and microprocessor, the combination of a plurality of microprocessors, one or more microprocessor and a DSP core or other this type of configuration arbitrarily.

Can directly implement in conjunction with the method for embodiment description disclosed herein or the step of algorithm with hardware, the software module of processor execution or the combination of the two.Software module can place the storage medium of other known in RAM memory, flash memory, ROM memory, eprom memory, eeprom memory, register, hard disk, moveable magnetic disc, CD-ROM or technical field form.Storage medium can be connected to processor, so that processor can be from read information and to the storage medium writing information.Replacedly, storage medium can be integrated in the processor.Processor and storage medium can place ASIC.ASIC can place user terminal.Processor and storage medium can be used as discrete assembly and place user terminal.

To the above-mentioned explanation of the disclosed embodiments, be in order to make those skilled in the art can realize or use the present invention.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined herein General Principle can realize under the situation that does not break away from the spirit or scope of the present invention in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet and principle disclosed herein and features of novelty the wideest consistent scope.Therefore, the present invention only is defined by the claims.

Claims (42)

1. equipment comprises:

Encoder, it is used for the multiple source bit stream is encoded, to produce a plurality of coded bit streams;

Bit-stream processor, it is used for adopting the different scramblers that dispose that each of described coded bit stream carried out scramble, to produce the bit stream of a plurality of different scrambles; With

Mapper, it is used for the bit groups of the bit stream of described a plurality of different scrambles is mapped to transmission symbol.

2. equipment as claimed in claim 1, wherein, described bit-stream processor also comprises rate matchers, described rate matchers is used for described coded bit stream is carried out rate-matched.

3. equipment as claimed in claim 1, wherein, described bit-stream processor also comprises interleaver, described interleaver is used for described a plurality of coded bit streams each interweaved.

4. equipment as claimed in claim 3, wherein, before in the described coded bit stream each carried out scramble, described interleaver interweaved to described coded bit stream.

5. equipment as claimed in claim 3, wherein, described interleaver interweaves in the bit stream of described scramble each.

6. equipment as claimed in claim 1, wherein, described scramble is carried out the xor operation between different pseudorandom scrambling sequences and the described a plurality of coded bit stream.

7. equipment as claimed in claim 1, wherein, described mapper is also based on predetermined modulation type, the bit groups of the bit stream of described a plurality of different scrambles is mapped in the transmission symbol, to generate a plurality of symbols streams.

8. equipment as claimed in claim 7, wherein, described modulation type comprises quarternary phase-shift keying (QPSK) (QPSK).

9. equipment as claimed in claim 7, wherein, described modulation type comprises quadrature amplitude modulation (qam).

10. equipment as claimed in claim 7 also comprises expander, and described expander is used for expanding described a plurality of mapped symbol stream by the common subset of walsh code, to generate a plurality of spread signals.

11. equipment as claimed in claim 1 also comprises:

A plurality of antennas, it is used for launching described symbol by wireless communication medium.

12. equipment as claimed in claim 11, wherein, the described symbol of described emission occurs in code division multiple access (CDMA) or OFDM (OFDM) system at least one.

13. an equipment comprises:

Encoder, it is used for the multiple source bit stream is encoded, to produce a plurality of coded bit streams;

Bit-stream processor, it is used for adopting different interlace modes that each of described coded bit stream interweaved, to produce the bit stream of a plurality of different interleavings; With

Mapper, it is used for the bit groups of the bit stream of described a plurality of different interleavings is mapped to transmission symbol.

14. an equipment comprises:

Encoder, it is used for the multiple source bit stream is encoded, to produce a plurality of coded bit streams;

Bit-stream processor, it is used on each coded bit stream adopting different perforation or repeat pattern and each of described coded bit stream is carried out rate-matched, to produce a plurality of different bit streams; With

Mapper, it is used for the bit groups of described a plurality of different bit streams is mapped to transmission symbol.

15. an equipment comprises:

De-mapping device, its symbol translation that is used for receiving becomes bit groups, to produce a plurality of reception bit streams;

Bit-stream processor, it is used for the different scramble algorithm application of separating is received bit stream in each, separates the bit stream of scramble to produce a plurality of differences; With

Decoder, its bit stream that is used for described difference is separated scramble is decoded, to produce a plurality of decoding bit streams.

16. equipment as claimed in claim 15, wherein, each is separated the scramble algorithm and removes the scrambling sequence that had before applied.

17. equipment as claimed in claim 15 also comprises:

The space time equalizer, it is used to generate the soft chip sequence of described receiving symbol; With

Solution Expander, it is used to generate a plurality of sequence of soft-symbols.

18. equipment as claimed in claim 17, wherein, described de-mapping device also to small part based on described a plurality of sequence of soft-symbols, generate a plurality of bit log-likelihood ratios (LLR) sequence.

19. equipment as claimed in claim 15, wherein, described bit-stream processor multiply by described reception bit stream and comprises { 1-2s _i(n) } the real-valued scrambling sequence of separating, wherein s _i(n) comprise i binary pseudorandom scrambling sequence.

20. an equipment comprises:

De-mapping device, its symbol translation that is used for receiving becomes bit groups, to produce a plurality of reception bit streams;

Bit-stream processor, it is used for that different deinterleaving patterns is applied to each and receives bit stream, to produce the bit stream of a plurality of different deinterleavings; With

Decoder, it is used for the bit stream of described different deinterleavings is decoded, to produce a plurality of decoding bit streams.

21. an equipment comprises:

De-mapping device, its symbol translation that is used for receiving becomes bit groups, to produce a plurality of reception bit streams;

Bit-stream processor, it is used for the different hole patterns of separating is applied to each reception bit stream, separates the bit stream of perforation to produce a plurality of differences; With

Decoder, its bit stream that is used for described difference is separated perforation is decoded, to produce a plurality of decoding bit streams.

22. one kind is used for comprising in many input-multi-output communication system method of transmitting information:

The multiple source bit stream is encoded, to produce a plurality of coded bit streams;

The scramblers that adopt different configurations carry out scramble in the described coded bit stream each, to produce the bit stream of a plurality of different scrambles; With

The bit groups of the bit stream of described a plurality of different scrambles is mapped in the transmission symbol.

23. method as claimed in claim 22 also comprises described coded bit stream is carried out rate-matched.

24. method as claimed in claim 22 also comprises in described a plurality of coded bit streams each interweaved.

25. method as claimed in claim 24, wherein, described interweaving also comprises, before in the described coded bit stream each carried out scramble, described coded bit stream interweaved.

26. method as claimed in claim 24, described interweaving also comprises in the bit stream of described scramble each interweaved.

27. method as claimed in claim 22, wherein, described scramble comprises the xor operation of carrying out between different pseudorandom scrambling sequences and the described a plurality of coded bit stream.

28. method as claimed in claim 22, wherein, described mapping comprises, based on predetermined modulation type, the bit groups of the bit stream of described a plurality of different scrambles is mapped in the transmission symbol, to generate a plurality of symbols streams.

29. method as claimed in claim 28, wherein, described modulation type comprises quarternary phase-shift keying (QPSK) (QPSK).

30. method as claimed in claim 28, wherein, described modulation type comprises quadrature amplitude modulation (qam).

31. method as claimed in claim 28 also comprises by the common subset of walsh code and expands described a plurality of mapped symbol stream, to generate a plurality of spread signals.

32. method as claimed in claim 22 also comprises by wireless communication medium and launches described symbol.

33. method as claimed in claim 32, wherein, the described symbol of described emission occurs in code division multiple access (CDMA) or OFDM (OFDM) system at least one.

34. one kind is used for comprising in many input-multi-output communication system method of transmitting information:

The multiple source bit stream is encoded, to produce a plurality of coded bit streams;

Adopt different interlace modes that in the described coded bit stream each interweaved, to produce the bit stream of a plurality of different interleavings; With

The bit groups of the bit stream of described a plurality of different interleavings is mapped in the transmission symbol.

35. one kind is used for comprising in many input-multi-output communication system method of transmitting information:

The multiple source bit stream is encoded, to produce a plurality of coded bit streams;

On each coded bit stream, adopt different perforation or repeat pattern and in the described coded bit stream each carried out rate-matched, to produce a plurality of different bit streams; With

The bit groups of described a plurality of different bit streams is mapped in the transmission symbol.

36. a method that is used for the information that receives at communicator comprises:

The symbol translation that receives is become bit groups, to produce a plurality of reception bit streams;

The different scramble algorithm application of separating is received bit stream in each, separate the bit stream of scramble to produce a plurality of differences; With

Described difference is separated the bit stream of scramble and decode, to produce a plurality of decoding bit streams.

37. method as claimed in claim 36, wherein, each is separated the scramble algorithm and removes the scrambling sequence that had before applied.

38. method as claimed in claim 36 also comprises:

Generate the soft chip sequence of described receiving symbol; With

Generate a plurality of sequence of soft-symbols.

39. method as claimed in claim 38, also comprise to small part based on described a plurality of sequence of soft-symbols, generate a plurality of bit log-likelihood ratios (LLR) sequence.

40. method as claimed in claim 36 also comprises described reception bit stream be multiply by comprising { 1-2s _i(n) } the real-valued scrambling sequence of separating, wherein s _i(n) comprise i binary pseudorandom scrambling sequence.

41. a method that is used for the information that receives at communicator comprises:

The symbol translation that receives is become bit groups, and produce a plurality of reception bit streams;

Different deinterleaving patterns is applied to each receives bit stream, to produce the bit stream of a plurality of different deinterleavings; With

Bit stream to described different deinterleavings is decoded, to produce a plurality of decoding bit streams.

42. a method that is used for the information that receives at communicator comprises:

The symbol translation that receives is become bit groups, and produce a plurality of reception bit streams;

The different hole patterns of separating is applied to each reception bit stream, separates the bit stream of perforation to produce a plurality of differences; With

Described difference is separated the bit stream of perforation and decode, to produce a plurality of decoding bit streams.

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