CN101291198A - Bit rearranging method and apparatus for retransmission in wireless communication system - Google Patents
Bit rearranging method and apparatus for retransmission in wireless communication system Download PDFInfo
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- CN101291198A CN101291198A CNA200710100827XA CN200710100827A CN101291198A CN 101291198 A CN101291198 A CN 101291198A CN A200710100827X A CNA200710100827X A CN A200710100827XA CN 200710100827 A CN200710100827 A CN 200710100827A CN 101291198 A CN101291198 A CN 101291198A
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Abstract
The invention provides a method for rearranging a bit position during the retransmission in a wireless communication system. The method comprises the following steps of: performing singular value decomposition to a received channel matrix H to acquire gain of each layer; calculating protective capability of each bit after retransmission and combination against various retransmission formats, according to the acquired gain of each layer; selecting the retransmission formats with similar protective capability of the bits; and rearranging the bit position according to the selected retransmission formats.
Description
Technical field
The present invention relates to a kind of method and apparatus of in the re-transmission of wireless communication system, rearranging bit; particularly; relate in the multiple-input and multiple-output precoding system; when being retransmitted, information bit rearranges bit; consider layer gain contrast spy's a protective capability, make protective capability after the merging each bit average method and apparatus of trying one's best.
Background technology
In high-speed data communication system, multiple data stream transmits simultaneously and can promote efficiency of transmission effectively.Multiple-input and multiple-output (MIMO:Multiple-Input Multiple-output) system promptly is an example of multi-data stream transmission system.The advantage of multi-input multi-output system is a plurality of available subchannels can be provided in the spatial domain, thereby can obtain diversity gain and spatial multiplexing gain by the different transmission technologys such as transmit diversity techniques or space division multiplexing technology etc., improve the error performance of transmission link therefrom, and improve spectrum efficiency etc.
In descending multi-input multi-output system, in order to improve received signal to noise ratio, reduce inter-user interference, (third generation partner program: the Long Term Evolution of Tao Luning (LTE:Long Term Evolution) motion Third Generation PartenershipProject), the mode of precoding is adopted in suggestion at 3GPP.Precoding is carried out SVD (singular value decomposition) to channel matrix exactly, utilizes right singular matrix that data are weighted at transmitting terminal (base station), at receiving terminal, utilizes left singular matrix that data are weighted.By above processing, obtain mutually independently parallel channel.
Fig. 1 shows the structure and the operation chart of part relevant with carrying out precoding in the multi-input multi-output system.As shown in Figure 1, in chnnel coding unit 100, the original information bits that will send is carried out chnnel coding, will be input to modulating unit 101 through the bit after the chnnel coding then and modulate.After obtaining modulation symbol, the original information bits of ovennodulation is imported into MIMO precoding unit 102.
The modulation symbol of 102 pairs of inputs of MIMO precoding unit carries out precoding.As shown in Figure 1, multi-input multi-output system can have M transmitting antenna, K reception antenna, N layer/stream of needs output (M 〉=N).The vector representation of supposing the modulation symbol of modulating unit 101 outputs is s=[s
1, s
2..., s
N]
T, then the transmission symbolic vector after the precoding can be used following expression (1) expression.
x＝V
Ns (1)
V wherein
NThe expression pre-coding matrix can be by receiving terminal 103 after receiving the symbolic vector that transmitting terminal sends, and channel H carried out SVD decompose and obtain, and wherein channel H is provided by following expression (2).
H＝UDV
H(2)
In expression formula (2), U is the left singular matrix of H, and V is the right singular matrix of H, and D is a diagonal matrix, and its cornerwise element is the singular value of H.In addition, U and V are unitary matrice.The diagonal entry of D is a
1, a
2..., a
M, and a
1＞a
2＞a
MV
NBe the preceding N row of matrix V, be the matrix of M * N.
By receiving terminal U
HSignal is weighted.Like this, the equivalent channel of the symbol before the precoding is shown in the channel schematic diagram of Fig. 1 bottom.Through after the precoding of transmitting terminal, the channel is-symbol s that it is equivalent
1Be a through gain
1Channel arrive receiving terminal, symbol s
2Be a through gain
2Channel arrive receiving terminal, and the like.Wherein, symbol s
1, s
2..., s
NThrough after the precoding, its equivalent channel is non-interfering parallel channel.At last, receiver detects and deciphers.
Concerning multistage modulation (for example, 16QAM, 64QAM or the like), the reliability of the bit in the signal constellation which is different, and each bit in the represented bit sequence of each constellation point has embodied different protective capabilities.Fig. 2 shows the planisphere of the gray mappings of 16QAM, and the ability of each the bit antagonism channel effect during the pairing bit of constellation point is represented also is not quite similar.For example, in 16QAM planisphere shown in Figure 2, each constellation point can be expressed as the bit sequence that 4 bits constitute, and promptly the order of the mapping of bit is i
1q
1i
2q
2Wherein bit is to i
1And q
1Be used to determine the quadrant at constellation point place, and bit is to i
2And q
2Then be used for distinguishing four different constellation point of same quadrant.In the bit sequence of same constellation point representative, bit is to (i
1q
1) protective capability, that is, and the antagonism channel fading ability, be higher than another bit to (i
2q
2) protective capability.In other words, i
1And q
1Be the bit of high reliability, i
2And q
2Bit for low reliability.Therefore, can be divided into two classes to 4 bits of each 16QAM symbol representative with different protective capabilities.Correspondingly, for 2
2nThe qam constellation figure of point, the bit sequence of each constellation point representative can be divided into the n class according to its protective capability.On planisphere, i
1And q
1The antagonism channel fading be the same with the ability of noise, i
2And q
2Be the same.
In " Enhanced HARQ Method with SignalConstellation Rearrangement " (referring to TSGR1#19 (01) 0237) that Panasonic company proposes, pointed out to have used high order modulation, the difference of the reliability of its bit, the inconsistent meeting of this performance cause the decreased performance (comparing with the reliability of same bits) of Turbocode decoder.For the reliability that makes bit obtains on average, above-mentioned document has provided and has improved the method that merges performance when retransmitting.The bit of transmission mapping for the first time for a symbol, represents that the bit mapping of this symbol is i in proper order as shown in Figure 2
1q
1i
2q
2If mistake has taken place in transmission for the first time, in general, when retransmitting, its bit position is exchanged.Therefore, be i during re-transmission to its bit position
2q
2i
1q
1, i.e. i
1And i
2Switch, q
1And q
2Switch.
Fig. 3 shows the schematic diagram of the bit exchange position of the bit that will hang down reliability when retransmitting symbol and high reliability.Its basic mode is the bit of low reliability when transmitting for the first time, when retransmitting and the bit exchange position of high reliability.Like this, the reliability that retransmits each bit when merging is average, can improve the performance of decoding.
As shown in Figure 2, to i
1, as long as the signal that receives drops on the left half-plane of Fig. 2, its decision bits is exactly 1 so, otherwise is exactly 0.In Fig. 4, provided i
1And i
2Protective capability.The first half of Fig. 4 has provided i
1Decision boundaries, the latter half of Fig. 4 has provided i
2Decision boundaries.
U.S. Pat 6476734 B2 that authorize people such as Jeong disclose a kind of " Method andAPPARATUS FOR PRIORITZING INFORMATION PROTECTION IN HIGH ORDERMODULATION SYBMOL MAPPING ".Described United States Patent (USP) has defined i quantitatively
1(q
1) and i
2(q
2) the difference of protective capability.The protective capability that Fig. 4 shows each bit of definition is the average constellation point schematic diagram to the distance of decision boundaries.As shown in Figure 4, to bit i
1, its distance is the average distance ds of two empty circles of Fig. 4 upper left-hand to decision boundaries
1, promptly shown in Fig. 4 upper left-hand solid circles.For bit i
2, its distance is the average distance ds of two empty circles in right side, Fig. 4 bottom to decision boundaries
2Obviously, d
1＞d
2So, bit i
1Performance be better than bit i
2Equally, for bit q
1And q
2Too.
In the discussion of LTE, in pre-coding system, code word has several situations to the mapping of layer.Fig. 5 shows under order equals 1 to 4 situation respectively, and code word is mapped to a plurality of layers and goes up issuable.As shown in Figure 5, when order=1, or order=2 o'clock, code word (CW1 and CW2) only is mapped on one deck.And when order=3 and order=4, a code word might be mapped on a plurality of layers.
In existing repeating method, different bits passing through in re-transmission switched between the bit of the bit of high reliability and low reliability so that rearrange the different bit of reliability and improves retransmission performance.In pre-coding system, when a code word was mapped to a plurality of layers, the not only reliability difference of the bit on the modulation constellation points, and the gain of different layers was also different.The method of prior art has only been considered the performance difference of bit on the planisphere, and does not consider the disequilibrium of gain between the different layers.
Fig. 6 has illustrated the different different schematic diagrames that can cause the difference of bit reliability with the constellation point position of the gain of layer.As shown in Figure 6, when a code word CW has been mapped to two layers, the gain of layer 1 is a
1, the gain of layer 2 is a
2(a
1＞a
2).Like this, be assigned to layer 1 the resulting gain of bit and be greater than the resulting gain of bit that is assigned to layer 2.In this case, the difference of the performance that the diverse location that not only exists bit to be mapped to modulation constellation points causes also exists the difference that is assigned to the bit performance that causes on the different layers.
In the MIMO pre-coding system, when a code word is transmitted on two or more layers, for high order modulation because the disequilibrium of gain between the mapping of constellation point and the different layer, cause the reliability of the bit in this encoding block change very greatly.Compare with the encoding block that bit reliability is average, the variation of this bit reliability has caused the loss of decoder performance.
In addition, when transmitted bit being retransmitted merging, the repeating method of prior art has only been considered the performance imbalance of the bit on the planisphere.But, bit reliability that like this can not the balance whole codeword.
Therefore, need to consider in the system of MIMO precoding, be mapped to when a code word under a plurality of layers the situation, how to carry out the performance that rearranging of bit improved re-transmission.
Summary of the invention
The purpose of this invention is to provide a kind of in wireless communication system, when the retransmission information bit, rearrange the device of the method for information bit position, this method and apparatus can be according to the disequilibrium of gain between the disequilibrium of the bit on the constellation point and the layer, re-construct the planisphere of equivalence, according to the planisphere of equivalence, rearrange the bit position when retransmitting.
According to an aspect of the present invention, provide a kind of method of rearranging the bit position when in wireless communication system, retransmitting, comprise step: the channel matrix H that receives is carried out singular value decomposition, obtain the gain of each layer; According to each layer gain that obtains, calculate the protective capability that retransmits each bit of merging back at various re-transmission forms; The re-transmission form that selection is roughly the same to the protective capability of bit; With rearrange the bit position according to the re-transmission form of selecting.
According to a further aspect in the invention, provide a kind of device of rearranging the bit position when in wireless communication system, retransmitting, comprising: channel estimating unit, the precoded modulation symbol that receives is carried out channel estimating, obtain channel matrix H; The singular value decomposition unit is used for channel matrix is carried out singular value decomposition, to obtain pre-coding matrix V
N, and according to the pre-coding matrix V that obtains
NObtain every layer gain; The protective capability computing unit according to the every layer of gain that obtains, calculates the protective capability that retransmits each bit of merging back at various re-transmission forms; And selected cell, select the re-transmission form roughly the same according to the protective capability of calculating to the protective capability of bit; And memory cell, be used to the re-transmission form corresponding index value of storing and selecting.
According to the present invention, taken all factors into consideration the bit on the constellation point disequilibrium and the layer between the gain disequilibrium.Re-construct the planisphere of equivalence, according to this equivalent planisphere, the bit position when considering to rearrange the retransmission information bit has near identical bit reliability the coded-bit after the merging, thereby improves the performance of decoder.
Description of drawings
By below in conjunction with description of drawings the preferred embodiments of the present invention, will make above-mentioned and other purpose of the present invention, feature and advantage clearer, wherein:
Fig. 1 is the structural representation that shows the MIMO pre-coding apparatus of prior art;
Fig. 2 shows the schematic diagram of the mapping relations of the planisphere of bit sequence of 16QAM constellation point and bit;
Planisphere when Fig. 3 shows retransmission bits sequence in the prior art and the schematic diagram of bit mapping relations;
Fig. 4 shows each bit i of definition
1(q
1) and i
2(q
2) protective capability be average constellation point schematic diagram to the distance of decision boundaries;
Fig. 5 a-5d shows the schematic diagram of code word to the mapping of different layers;
Fig. 6 shows the unbalanced schematic diagram of bit reliability that layer causes with planisphere;
Fig. 7 shows the schematic diagram of the equivalent planisphere of two layers constructed according to the invention;
Fig. 8 shows according to the present invention at the schematic diagram of the protective capability of considering the special sequence of layer gain contrast;
Fig. 9 shows the schematic diagram of the reliability constraint relation when the retransmission bits sequence;
Figure 10 be in 16QAM, list according to one embodiment of present invention two kinds may arrangement modes schematic diagram;
Figure 11 is the schematic diagram of the re-transmission form that obtains according to one embodiment of present invention;
Figure 12 is a flow chart of rearranging the method for information bit position during according to embodiment of the invention retransmission information bit; With
Figure 13 shows the block diagram of the device of the method for rearranging the information bit position when the retransmission information bit.
Embodiment
With reference to the accompanying drawings embodiments of the invention are described in detail, having omitted in the description process is unnecessary details and function for the present invention, obscures to prevent that the understanding of the present invention from causing.
In the MIMO pre-coding system, can precompute the gain of each layer.Based on these characteristics, according to the present invention, when the retransmission bits sequence, consideration is united in the gain of different layers and the gain of planisphere, defined equivalent planisphere.In other words, the different protective capabilities that the special sequence of gain contrast of diverse location in the different gains of different layers and the planisphere is produced constitute equivalent planisphere.Then, according to equivalent planisphere, calculate protective capability to each bit in the bit sequence.When the retransmission bits sequence,, make the protective capability after the merging average as far as possible to each bit according to the protective capability of transmitting previously with according to the protective capability that precoding is calculated.
According to this method, can preestablish the form of several retransmission bits sequences.Default re-transmission form can be stored in transmitting terminal or the receiving terminal, and perhaps transmitting terminal and receiving terminal are all stored default re-transmission form.At receiving terminal, from these several default forms, select average a kind of of the reliability of each bit in the bit sequence, then, the index value of this form is turned back to transmitting terminal, transmitting terminal is according to this index value, select corresponding re-transmission form, before transmission, the bit sequence that retransmits is rearranged, retransmit then.According to this method, because receiving terminal only feeds back the index value of selected re-transmission form to transmitting terminal, and select corresponding re-transmission form according to the index value of feedback at transmitting terminal, therefore reduced the feedack amount.
When the code word that will retransmit being described below being mapped to different layers, the imbalance that the gain contrast spy's that each layer is different reliability produces.For simplicity, can suppose that a code word is mapped to two-layer.In addition, the bit of re-transmission is i
1q
1i
2q
2, the residing position of retransmission bits is not limited to the order mentioned.With reference to the Fig. 6 that has described, if the gain of two layers is respectively a
1(layer 1) and a
2(layer 2) for the signal by these two layers, is equivalent to this signal is amplified respectively (or dwindling) and is original a
1Doubly and a
2Doubly.If the gain of layer is folded in the planisphere, the symbol that then is equivalent to send directly adds Gaussian noise.In this case, might constitute the equivalent planisphere of two layers as shown in Figure 7.In equivalent planisphere shown in Figure 7, the equivalent constellation point of empty circles " zero " presentation layer 1, the equivalent planisphere of cross " * " presentation layer 2.
The protective capability of each bit that provides according to prior figures 4 is the definition to the distance of decision boundaries of average constellation point, on the equivalent planisphere that provides from Fig. 7 as can be seen, i
1Reliability to be higher than i
2, but situation is not necessarily like this concerning different layers.
Fig. 8 has provided and has considered the special protective capability of layer gain contrast.This protective capability is represented to the product of the average distance of decision boundaries by the gain of layer and the constellation point of bit.I to layer 1
2Bit is because the gain of its layer is a
1, its average distance to decision boundaries is d
2Therefore (as shown in Figure 8), to the i of layer 1
2The protective capability of bit is a just
1d
2Equally, to the i of layer 2
1The protective capability of bit is a
2d
1If a
1d
2＞a
2d
1, then think layer 1 i
2The reliability of bit will be higher than the i of layer 2
1Bit.Otherwise, if a
1d
2＜a
2d
1, then think layer 2 i
1The reliability of bit will be higher than the i of layer 1
2Bit.
In order to make the reliability that retransmits each bit that obtains when merging average.According to embodiments of the invention,, after k transmission, can provide with following expression (1) through the protective capability of the bit after merging based on the equivalent protection ability of equivalent planisphere and Fig. 8 of Fig. 7.
A wherein
m(p) the m layer gain of the p time transmission of expression (this bit has been assigned to the m layer in the p time transmission); d
n(p) in the p time transmission of expression, this bit is mapped in the protective capability on the modulation constellation, as shown in Figure 4 (16QAM).In the superincumbent expression formula, protective capability sum when the protective capability definition after merging is respectively each transmission.If the position of bit on modulation constellation of transmission is i for the first time
1, i
2, q
1, q
2, then definition,
Di
1: for merging back i through retransmitting
1Protective capability;
Di
2: for merging back i through retransmitting
2Protective capability
Dq
1: for merging back q through retransmitting
1Protective capability;
Dq
2: for merging back q through retransmitting
2Protective capability.
In addition, for the k time transmission, before it once, promptly the k-1 time, the protective capability of re-transmission merging be known, required is with bit i
1, i
2, q
1, q
2Be mapped to different layers and get on,, that is, satisfy the relation that following expression (2) provides so that the protective capability of each bit of re-transmission merging back is roughly the same with different bit positions.
Di
1≈Di
2≈Dq
1≈Dq
2 (4)
Be the protective capability of example explanation with corresponding two layers of a code word below, determine the example of the re-transmission position of bit according to each bit.In the following description, being modulated to example with 16QAM is described.Be noted that to the invention is not restricted to the 16QAM modulation, but can be applied to other high order modulation, modulate as 64QAM etc.
As shown in Figure 6, in transmission course, can be with Bit Allocation in Discrete to four position.Can be with the i of layer 1
1(or q
1) bit definitions is i
1(1); The i of layer 1
2(or q
2) bit definitions is i
2(1); The i of layer 2
1(or q
1) bit definitions is i
1(2); The i of layer 2
2(or q
2) bit definitions is i
2(2).In these four positions, be different to the protective capability of bit.If four positions of transmission are i for the first time
1(1), i
2(1), i
1(2), i
2(2), when retransmitting, a bit can be assigned to four positions.Like this, four bits one have the possible transmission means of 4 * 3 * 2=24 kind.
Yet in fact, according to the requirement of expression formula (4), not all possible transmission means all is useful.This is that its position in retransmission processes is subjected to the constraint of reliability because there is fixed relationship these four kinds of possible positions.
Fig. 9 shows the schematic diagram of the reliability constraint relation when the retransmission bits sequence.As shown in Figure 9, concerning the bit of same layer (gain of this layer is identical), owing to weigh bit i
1The value d of protective capability
1(referring to Fig. 4) is greater than and weighs bit i
2The value d of protective capability
2So, i
1Reliability be greater than i
2Reliability.And concerning different layers, because layer 1 gain be greater than the gain of layer 2, for the bit with same protective capability on the modulation constellation points, the bit on the layer 1 is stronger than the protective capability of the bit on the layer 2.In other words, i
1(1) reliability of (the numeral layer in the bracket) is greater than i
1(2) reliability; i
2(1) reliability of (the numeral layer in the bracket) is greater than i
2(2) reliability.Like this, according to the ratio of the a2 of above constraint and a1, has only the form of two kinds of possible equivalent planispheres.Figure 10 shows the schematic diagram of these two kinds possibility arrangement modes.In Figure 10, increase from low to high according to from left to right direction indication protective capability, as shown by arrows.As shown in figure 10, empty circles " zero " expression is to the mapping of layer 1, and cross " * " expression is to the mapping of layer 2.Mode 1 among Figure 10 and mode have provided the equivalent planisphere of transmission for the first time respectively.
Figure 11 has provided the requirement according to expression formula (4), that is, make the protective capability that retransmit to merge each bit of back roughly the same, the mode of the pairing re-transmission of various combination of arranging in the reliability of transmission for the first time and transmission for the second time.
In Figure 11, the relation of the bit of the different reliabilities of different layers when transmitting is for the first time shown in first tabulation, and reliability from left to right (protective capability) is arranged from low to high.The relation of the bit of the different reliabilities of different layers when secondary series is represented to transmit for the second time.The 3rd classifies the correlation according to first row and secondary series as, according to the requirement of expression formula (4), and the position of each bit when arranging to retransmit.From Figure 11 the 3rd row as can be seen, in accordance with the order from top to bottom, first with the 4th kind to retransmit form be identical, second and the third re-transmission form be identical.Therefore, have the possible transmission means of 4 * 3 * 2=24 kind, in fact need only the peculiar approaching identical bit reliability of encoding ratio after four kinds of re-transmission modes can make merging though the front has illustrated four bits one.
Below with reference to Figure 10 and Figure 11 the two kinds of examples that can plant possible re-transmission form of formation are described.The gain a of ground floor when supposing to transmit for the first time
1(1)=3 (expression of 1 in bracket transmission for the first time), the gain of the second layer is a
2(1)=2.For modulation constellation, d
1=2d
2(can establish d
2=1).Therefore to i
2The protective capability of equivalence (2) is a
2d
2=2; To i
1(2) protective capability a
2d
1=4; To i
2(1) protective capability a
1d
2=3; To i
1(1) protective capability a
1d
1=6.The ability that can be protected thus putting in order from low to high is i
2(2)＜i
2(1)＜i
1(2)＜i
1(1), it puts in order shown in the mode 1 of Figure 10.
In the time of need transmitting again when in transmission for the first time, having taken place wrong.Since need precoding, the gain of layer when receiving terminal has been calculated re-transmission in advance, and the gain of ground floor is a when supposing to transmit for the second time
1(2)=4 (expression of 2 in bracket transmission for the second time), the gain of the second layer is a
2(2)=1.5.Equally, for modulation constellation, d
1=2d
2(can establish d
2=1).When then transmitting for the second time to i
2(2) protective capability is a
2d
2=1.5; To i
1(2) protective capability is a
2d
1=3; To i
2(1) protective capability is a
1d
2=4; To i
2(1) protective capability is a
1d
1=8.At this moment, be i according to protective capability putting in order from low to high
2(2)＜i
1(2)＜i
2(1)＜i
1(1), its arrangement mode is shown in the mode 2 of Figure 10.
The bit of transmission can be arranged on the position of four kinds of different protective capabilities when retransmitting for the first time.According to the requirement of expression formula (4), the protective capability that makes each bit after the merging is average (calculating of the protective capability after the merging is referring to expression formula (3)) substantially.Arrangement when then retransmitting is shown in tertial the third line of Figure 11.The i.e. i of transmission for the first time
1(1) (transmission for the second time) has been put into i when retransmitting
2(2) position; The i of the transmission first time
1(2) (transmission for the second time) has been put into i when retransmitting
2(1) position; The i of the transmission first time
2(1) (transmission for the second time) has been put into i when retransmitting
2(1) position; The i of the transmission first time
2(2) (transmission for the second time) has been put into i when retransmitting
1(1) position.In other words, obtained i
1(1) i
1(2) i
2(1) i
2(2) re-transmission form.If when retransmitting, transmitting terminal is known the arrangement mode (Figure 11 first row) of the equivalent planisphere when transmitting for the first time, also knows the arrangement mode (Figure 11 secondary series) of the equivalent planisphere when retransmitting, when retransmitting so, the also index value of feedback format not, both sides obtain retransmitting form according to tabling look-up.If when retransmitting, transmitting terminal is known the arrangement mode (Figure 11 first row) of the equivalent planisphere when transmitting for the first time, but the arrangement mode of the equivalent planisphere when not knowing to retransmit (Figure 11 secondary series), when retransmitting so, the recipient feeds back the arrangement mode (Figure 11 secondary series) of the equivalent planisphere when retransmitting, transmit leg obtains retransmitting form according to tabling look-up, and this situation arrangement mode has two kinds of possibilities.If transmitting terminal knows that neither the recipient feeds back the index value that retransmits form so, this situation has four kinds of possibilities.
Below with reference to the flow chart of Figure 12 description according to the repeating method of embodiment of the invention retransmission information bit.At first, in step S1200, channel matrix H is carried out singular value decomposition, obtain the gain of each layer by receiving terminal.In addition, in step S1201, preestablish the form of several retransmission bits sequences.Default re-transmission form can be stored in transmitting terminal or the receiving terminal, and perhaps transmitting terminal and receiving terminal are all stored default re-transmission form.In step S1202, calculate the protective capability that retransmits each bit of merging back at various re-transmission forms.After this, in step S1203, select re-transmission form to the protective capability average (roughly the same) of bit.Next, at step S1204, the index value of the re-transmission form selected is fed back to transmitting terminal.Position when transmitting terminal arranges bit to retransmit according to this indication that retransmits form.
Be noted that the present invention is not limited to be applied to 16QAM modulation, for 64QAM and the more modulation of high-order, the form that can obtain retransmitting with similar method equally.
Figure 13 shows an embodiment of the device of rearranging the information bit form when the retransmission information bit.Being noted that for simplicity, only having provided among Figure 13 and the relevant unit of execution method of the present invention, is unnecessary details and function and omitted for the present invention, obscures to prevent that the understanding of the present invention from causing.
As shown in figure 13, according to this embodiment, the device of rearranging the information bit form is arranged on receiving terminal, comprises channel estimating unit 131, SVD resolving cell 132, protective capability computing unit 133, selected cell 134 and memory 135.
The operation of the device of rearranging the information bit form is described below with reference to Figure 13.The precoded modulation symbol that sends by the reception antenna receiving end/sending end, and the precoded modulation symbol that is received offered channel estimating unit 131.The precoded modulation symbol of 131 pairs of receptions of channel estimating unit is carried out channel estimating, obtains channel matrix H, and channel matrix H is offered SVD resolving cell 132.132 couples of channel H of SVD resolving cell carry out the SVD decomposition and obtain pre-coding matrix V
NAnd obtain every layer gain (detailed process reference expression formula (1) and (2) describe) in front thus.Every layer the gain that protective capability computing unit 133 provides according to SVD resolving cell 132 is calculated the protective capability that retransmits each bit of merging back at various re-transmission forms, and the protective capability of calculating is offered selected cell 134.Selected cell 134.Selected cell 134 is selected the re-transmission form average to the protective capability of bit.In the embodiment shown in fig. 13, memory 135 storage preestablishes the form of several retransmission bits sequences, or with retransmit the form corresponding index value.Selected cell 134 can feed back to transmitting terminal with re-transmission form or its corresponding index value of selecting.Position when transmitting terminal arranges bit to retransmit according to this indication that retransmits form.
Owing in pre-coding system, can precompute the gain of layer, therefore can utilize these characteristics to arrange the position of bit re-transmission, make the reliability of all bits in the code word that retransmits after merging average, thereby improve the decoding performance that retransmits after merging.
So far invention has been described in conjunction with the preferred embodiments.It should be appreciated by those skilled in the art that under the situation that does not break away from the spirit and scope of the present invention, can carry out various other change, replacement and interpolations.Therefore, scope of the present invention should not be understood that to be limited to above-mentioned specific embodiment, and should be limited by claims.
Claims (12)
1. method of rearranging the bit position in wireless communication system when retransmitting comprises step:
The channel matrix H that receives is carried out singular value decomposition, obtain the gain of each layer;
According to each layer gain that obtains, calculate the protective capability that retransmits each bit of merging back at various re-transmission forms;
The re-transmission form that selection is roughly the same to the protective capability of bit; With
Rearrange the bit position according to the re-transmission form of selecting.
2. method according to claim 1 further comprises the step of the form that preestablishes a kind of at least retransmission bits sequence.
3. method according to claim 1 comprises that further the re-transmission form that will select feeds back to the step of transmitting terminal.
4. according to claim 1 or 3 described methods, further comprise and to feed back to the step of transmitting terminal with selected re-transmission form corresponding index value.
5. method according to claim 1, wherein according to following expression calculate after k the transmission through the protective capability D of the bit after the merging,
A wherein
m(p) the m layer gain of the p time transmission of expression; d
n(p) in the p time transmission of expression, this bit is mapped in the protective capability on the modulation constellation, the protective capability sum the when protective capability after the merging is each the transmission.
6. method according to claim 1 comprises that further the gain according to diverse location in the different gains of different layers and the planisphere constitutes the step of equivalent planisphere to the different protective capabilities that each bit produced.
7. according to claim 1 to 3, any one the described method in 5 and 6, wherein said wireless communication system is the multiple-input and multiple-output precoding system.
8. method according to claim 4, wherein said wireless communication system are the multiple-input and multiple-output precoding systems.
9. device of rearranging the bit position in wireless communication system when retransmitting comprises:
Channel estimating unit is carried out channel estimating to the precoded modulation symbol that receives, and obtains channel matrix H;
The singular value decomposition unit is used for channel matrix is carried out singular value decomposition, to obtain pre-coding matrix V
N, and according to the pre-coding matrix V that obtains
NObtain every layer gain;
The protective capability computing unit according to the every layer of gain that obtains, calculates the protective capability that retransmits each bit of merging back at various re-transmission forms; With
Selected cell is selected the re-transmission form roughly the same to the protective capability of bit according to the protective capability of calculating; With
Memory cell is used to the re-transmission form corresponding index value of storing and selecting.
10. device according to claim 9, wherein said cell stores preestablish a kind of at least re-transmission form of retransmission bits.
11. device according to claim 9, wherein said selected cell will feed back to transmitting terminal with the re-transmission form corresponding index value of selecting.
12. according to any one the described device in the claim 9 to 11, wherein said described wireless communication system is the multiple-input and multiple-output precoding system.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010083709A1 (en) * | 2009-01-21 | 2010-07-29 | 中兴通讯股份有限公司 | Method and device for mapping code word streams to layers in multi-input multi-output system |
| CN101931515A (en) * | 2009-06-19 | 2010-12-29 | 大唐移动通信设备有限公司 | Data retransmission method, system and device |
| CN102547737A (en) * | 2010-12-30 | 2012-07-04 | 中兴通讯股份有限公司 | Method and system for suppressing downlink interference |
| CN103457687A (en) * | 2012-05-29 | 2013-12-18 | 上海贝尔股份有限公司 | Relaying method and device based on bit rearrangement |
| WO2018058448A1 (en) * | 2016-09-29 | 2018-04-05 | 华为技术有限公司 | Data transmission method and device |
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2007
- 2007-04-18 CN CNA200710100827XA patent/CN101291198A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010083709A1 (en) * | 2009-01-21 | 2010-07-29 | 中兴通讯股份有限公司 | Method and device for mapping code word streams to layers in multi-input multi-output system |
| US8488564B2 (en) | 2009-01-21 | 2013-07-16 | Zte Corporation | Method and device for mapping a codeword to a layer in a multi-input multi-output system |
| CN101465718B (en) * | 2009-01-21 | 2013-11-06 | 中兴通讯股份有限公司 | Method and apparatus for mapping codeword current to layer in multi-input multi-output system |
| CN101931515A (en) * | 2009-06-19 | 2010-12-29 | 大唐移动通信设备有限公司 | Data retransmission method, system and device |
| CN102547737A (en) * | 2010-12-30 | 2012-07-04 | 中兴通讯股份有限公司 | Method and system for suppressing downlink interference |
| CN103457687A (en) * | 2012-05-29 | 2013-12-18 | 上海贝尔股份有限公司 | Relaying method and device based on bit rearrangement |
| WO2018058448A1 (en) * | 2016-09-29 | 2018-04-05 | 华为技术有限公司 | Data transmission method and device |
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