CN102724019A - Method and system for transmitting sub-band indication - Google Patents

Abstract

The invention relates to a method and a system for a first transceiver to transmit sub-band signals with markers to a second transceiver in a wireless data communication system. Communication resources are divided into frequency sub-bands (n1,...,nN) to form a sub-band set, wherein the first transceiver transmits markers of frequency sub-band sets (m1,...,mQ) to the second transceiver. The method includes the steps: establishing subset groups, wherein each subset (m1,...,mQ) in one group comprises the sub-band markers identical in number, and the subsets (m1,...,mQ) in the group are sequenced; and indicating the markers of the sub-band subsets (m1,...,mQ) transmitted from the first transceiver to the second transceiver by the markers of the subsets in the group and positions of the subsets in the group.

Description

Send the method and system of subband indication

Technical field

The present invention relates to send the method and system of subband indication.

Background technology

In the UTRA of 3GPP evolution (E-UTRA), frequency domain dispatching is very important characteristic.For schedule downlink under the situation of frequency domain duplex, need be from the frequency dependent channel quality information of portable terminal to base station (Node B) emission one definite form.In E-UTRA, send channel quality indication (CQI) comes reporting channel quality.Whole frequency band can be divided into subband, wherein is the independent estimated channel quality indication of each subband (CQI).

Have, in the E-UTRA that uses the MIMO precoding, receiver sends preferred precoding vectors index (PVI) with this preferred MIMO precoding vectors of report to Node B again.In this case, because the frequency selectivity of channel, whole bandwidth also need be divided into subband, and estimates PVI separately for each subband.

The direct method of transmitting channel quality or precoding vectors information is to send the PVI and the CQI of all subbands.Yet this method can produce sizable signaling.Therefore, several kinds of alternative methods of signaling have been proposed to reduce.Here only introduce first method in detail; These methods comprise: only feedback have best CQI the Q sub-band information, use differential feedback information in time domain or frequency domain, use bitmap to indicate which or which subband to feed back report CQI/PVI value, use hierarchical tree structure and use the orthogonal function set to approach the profile (frequency selective fading profile) that declines of choosing frequently, referring to the 3GPP TR 25.814 in December, 2005 v.1.0.1 " Physical Layer Aspects for Evolved UTRA (physical layer part of evolution UTRA) ".

First method can further be described in detail through following method: send a CQI value of the best Q subband of representative and send the index of these subbands and the CQI that whole frequency band is represented in transmission.All send the method for CQI compares with each subband; This method only has very little reduction on throughput; Referring in January, 2006 3GPP TSG RAN; R1-060228, Huawei, " Sensitivity of DL/UL Performance to CQI-Compression with Text Proposal (the downlink/uplink performance is to the susceptibility of CQI-compression) ".

Yet the major issue of this method is the index of how indicating CQI report (also having the PVI report when a precoding MIMO) pairing Q subband with minimum signaling.If exist N subband to be expressed as 1,2 respectively ..., N, and therefore constitute the N sets of subbands then can send the N bit sequence, and the corresponding bit of wherein specific Q subband index for example can be set to 1 and the remaining bits position is set to 0.Yet this method requires sizable signaling.

An example of the existing compress technique of bitmap is generally a long codes; Referring to A.Bookstein and S.T.Klein; " Construction of Optimal Graphs for Bit-Vector Compression (structure of the optimum figure of bit vectors compression) ", the 13rd of international ACM SIGIR meeting is about information Study of Recovery and exploitation conference procceedings, pp 327-342; 1990; Brussels, Belgium can represent with the sign of indication 1/0 and 1/0 number for wherein continuous one group 1/0.Yet, can not guarantee that such compress technique always can compress input, especially in for example indicating 24 subbands 5 the time, at this moment selected subband 24 maybe in distribute arbitrarily.

A more efficiently method relies on $\left(\begin{array}{c}N\\ Q\end{array}\right)$ Kind method is selected Q subband from N subband, wherein $\left(\begin{array}{c}n\\ k\end{array}\right)$ Be binomial coefficient:

$\left(\begin{array}{c}n\\ k\end{array}\right)=\frac{n!}{k!(n-k)!},$ $k!=\left\{\begin{array}{cc}1,& k=0\\ 1\·2\·3\·\·\·k,& k>0\end{array}\right.---\left(1\right)$

Therefore; In order to transmit the individual index of Q in N the subband; With respect to the N bit method for expressing that uses simple bitmap, binomial method then needs

individual bit at least.

expression is more than or equal to the smallest positive integral of x.For example, if N=24 and Q=5 for bitmap, need 24 bits to indicate, but said method only need 16 bits.Like this, when sending the subband index signal, can reduce the lot of data signaling and send.

The direct method that a kind of possible subclass that will be selected from Q subband of N subband is mapped to required minimum number bit is with they tabulations.The possible subclass of Q subband increases very fast with the increase of Q.For example, when N=24 and Q=5, exist to surpass 40,000 different subsets.Yet, conciliate existing problems in the mapping in mapping fast and effectively in the form of possibility subclass.

Therefore, need to send improving one's methods of subband sign.

Summary of the invention

The object of the present invention is to provide the system and method that first transceiver identifies to second transceiver transmission subband in a kind of wireless data communication system, this method and system provides and has obtained the more effective ways that the subband particular subset is represented.

The present invention sets up the subclass group; Wherein each subclass comprises same number subband sign in the group; Subclass in the group is sorted; And from the sign of first transceiver to second transceiver transmission subband subclass, the sign of described subband subclass is to represent through sign and this position of subband subclass in the group of place of the group at this subband subclass place.For example, available digital r representes the subclass of subband, and wherein r is confirmed by subclass group id and the position of subclass in group.

This helps first transceiver, such as portable terminal, obtains with simple and effective and efficient manner and to send to second transceiver, representes such as the subclass of base station.Further, help travelling carriage quickly and use less resources to obtain said expression.Can in sending CQI, PVI and/or any other subband special parameter, use the step of said transmission subband subclass.

Confirm the sign of group with the group particular offset.This helps obtaining sign with simple mode.

This method further may further comprise the steps, wherein subband with (1 ..., N) index:

A) the subclass m in will organizing ₁..., m _Q, ordering, minimum index m in the at first arrangement group ₁Next subclass with the highest probable value n is the subclass of n-1 for minimum index, and the like, up to minimum index be all subclass of 1 till;

B) i=1 is set;

C) to minimum index m ₁All subclass that equate sort, if perhaps i＞1, to minimum index m ₁..., m _iThe subclass that equates sorts, and like this, first subclass is minimum residue index m _I+1Having the subclass of high probable value, is that minimum residue index has time the subclass of high probable value then, and the rest may be inferred, is m up to minimum residue index _iTill all subclass of+1;

D) i=i+1 is set, and repeats step c) till i=Q-1.

This helps obtaining quickly the expression of particular subset.Have again,, can save considerable internal memory in the portable terminal owing to using mathematical computations rather than tabling look-up and carry out these steps.

The invention still further relates to a kind of system and communication system.

Below in conjunction with accompanying drawing the present invention is elaborated.

Description of drawings

Fig. 1 illustrates the exemplary wireless data communication system that utilizes advantage of the present invention.

Fig. 2 illustrate in the communication system of Fig. 1 maybe the communication resource example.

Embodiment

Fig. 1 illustrates communication system 1, wherein can utilize advantage of the present invention.Antenna for base station 2 shown in the figure has the ability that communicates with one or more portable terminals 3.The communication resource comprises that at least one is divided into the frequency band of subband.Specified the division of frequency band among Fig. 2, wherein shown to be applicable to communication resource scheme of the present invention.As shown in the figure, the frequency spectrum of communication system is divided into 24 subband (n that for example form the frequency spectrum five equilibrium ₁..., n _N), this is because the equifrequency subband helps resource management (for example, distributing available resources easily).Certainly, also can be divided into the not subband of equifrequency.

Can the communication resource be divided into a plurality of time slot (not shown) in time domain; A time slot has certain length in time; For example a time slot comprises a plurality of OFDM symbols, wherein in one or more subbands, can distribute one or more time slots of all or part for a user.In addition, can distribute all or part subband for a user, wherein one or more users constantly communicate on same subband.

Communication system among Fig. 1 has only shown a base station.Yet, one skilled in the art will appreciate that communication system 1 can comprise a plurality of base stations, each base station covers the part of communication system.Have, the overlay area of a base station can be divided into the sector again.

The channel quality of specific travelling carriage can great changes have taken place on a plurality of subbands, even between adjacent two nearer subbands, such as the n in Fig. 2 ₁And n ₂Or n ₁And n ₃Between.Therefore,, need travelling carriage, such as channel quality (CQI) and preferred precoding vectors index (PVI) to base station transfer channel parameter in order to effectively utilize the communication resource as far as possible.Because parameter is different between the subband, so need send this information to the base station.Yet as stated, sending all sub-band channel parameters needs very big signaling amount, and the method that reduces this signaling transmission is the sign of only sending the good subband of those conditions.In addition, if most channel can provide satisfied attribute, those provide the attribute of the subband of poor channel attribute can to change transmission into, because can greater flexibility be provided for the base station assigns channel resource like this.

However; Owing to be the available bandwidth that effectively utilizes wireless communication system as far as possible, should inform as far as possible effectively that the base station sends the required data volume of sign of limited number subband, promptly; If think that each subclass of Q subband is the bitmap of N bit; The bit of Q wherein is 1, and the problem that then will solve is how to send altogether the index of Q subband in N the subband with minimum number bit, and allows the fast mapping from the subset of indices to the bit sequence and separate mapping fast.

Mapping can be regarded as the compression from the bitmap of N bit, and wherein original bitmap has the restriction that has Q individual 1.The problem that solve then, is a kind of effective bitmap compression of design.

As stated, in order to transmit the index of Q subband in N the subband,

Need

bit to come to send index to base station (Node B) from travelling carriage.Have substantial improvement though compare this with the use simple bitmap, as stated, still with regard to the very important point be, travelling carriage can enough very short time cycles and the definite special expression of representing Q subband in N the subband of minimum load when handling resource.

For example, shown in Figure 1, there are 24 subbands, i.e. N=24, wherein 51 specific (Q=5) will send the base station to, then exist to surpass possible combination in 40,000.Yet digital N can be bigger, and this depends on bandwidth usually.For the bandwidth of 20MHz, N is 48.Have, the subband sign (index) that allows usually to send any number is up to given maximum number again.With identical example,, then exist 55,000 kinds possibly make up if allow any number subband up to 5.If each possible combination identifies with a numeral, be difficult to effectively and obtain apace the specific number that sends to the base station (for example representing) with binary form.

The subband index subclass that the present invention provides a kind of mode with fast mapping reconciliation mapping will be selected from N subband total collection is mapped to the method for minimum number bit.

Usually, with unique nonnegative integer set M={m ₁, m ₂..., m _JCome to allowing number of sub-bands Q, wherein 0≤m in the subset _j≤N, j=1,2 ..., J.

Required mapping might subclass number of bits be:

Because the minimizing degree of the signaling amount that this mapping causes depends on N and set M.In the above-mentioned example, exist altogether N=24 subband and preferably the subclass of subband comprise 0 to 5 subband, i.e. M={0,1,2,3,4,5}, index are 0,1,2,3,4 or 5 subband only uses:

individual bit (4)

Rather than N=24 bit.

Among the present invention, the index of each subclass is with a digital r mark, and for example a sub-set can comprise index 1,7,12,15,21.The index of subclass is mapped on the bit sequence of the binary representation of r for example.Yet, it will be apparent to those skilled in the art that digital r also can be mapped on another alphabetic(al) symbol sebolic addressing, representes or decimal representation such as ternary.

When r was mapped on the binary sequence of

bit, the scope of r was

Among the present invention, the scope of r is divided into J at interval, and all the r values in the J are represented m so at interval _jThe subclass of individual index.Minimum r is called j skew Q in the j at interval _jEach must have m to comprising all greatly at interval _jThe subclass of individual index, that is:

$O_{j+1}\≥\left(\begin{array}{c}N\\ m_j\end{array}\right)+O_j,$ J=1,2 ..., J-1 and $O_J\≤2^{\tilde{N}}-1-\left(\begin{array}{c}N\\ m_J\end{array}\right)---\left(5\right)$

Must be effectively.Minimum possibly squint and be given as:

$O_j=\underset{k=1}{\overset{j-1}{\mathrm{\Σ}}}\left(\begin{array}{c}N\\ m_k\end{array}\right),$ j＝1，2，...，J (6)

Use N=5, M={m ₁=0, m ₂=1, m ₃=2} with

Example further illustrate the present invention program.In example, squinting is O ₁=0, O ₂=1, O ₃=6.Therefore, as shown in table 1, r=0 is a vacuous subset, and 1≤r≤5 are for containing the subclass of an index, and 6≤r≤15 are the subclass of two index.

Table 1

Therefore, obtain mark Q=m _jThe digital r of subset of indices is through skew O _jAdd the position of this subclass in the subclass group.Above-mentioned O _jDefinition only as an example, also can use the definition of multiple additive method.For example, can calculate O _jBe last position in the subclass group, wherein obtaining digital r is O _jDeduct certain numeral.Use the above-mentioned method that the r scope is divided at interval or organized, can obtain quickish " tabling look-up ", promptly travelling carriage can more effectively identify the specific r that will transmit than prior art.Like this, the base station can receive one and measure more accurately, particularly suffers frequent during with unexpected change when travelling carriage fast moving or propagation characteristic.Have, the present invention also helps the load that reduces mobile terminal processor again.

Yet, can further strengthen said method through introducing additional step, below this step of explanation.

Among the optional embodiment, this additional step comprises with effective and efficient manner the ordering of the subclass in every group.

At first, a plurality of index to a sub-set sort.The span of each subclass Q index is from 1 to N, can be expressed as through the subclass of index order:

${\left\{s_k\right\}}_{k=0}^{Q-1},$ Wherein $\begin{array}{c}1\&le;s_k\&le;N\\ s_k<s_{k+1}\end{array}---\left(7\right)$

Next, come the subclass in the group is sorted with following method.First subclass in the group is for having s ₀The subclass of=N-Q+1 is to have s subsequently ₀All subclass of=N-Q, the rest may be inferred, till all subclass of s0=1.

Next step is to containing index s ₀All subclass of=x sort, and that at first find is s ₁All subclass of=N-Q+2 are followed by s ₁The subclass of=N-Q+1, the rest may be inferred, up to s ₁All subclass of=x+1.For each index k in the subclass, repeat the same program of ranking index subclass.For Q=0, having only singleton to exist does not need ordering.Therefore, r is given as skew O _jAdd Q index all greater than s ₀All subclass numbers, add that Q-1 index is all greater than s ₁All subclass numbers, the rest may be inferred.

Table 2 has been explained earlier examples N=5, M={m ₁=0, m ₂=1, m ₃=2} and skew O ₁=0, O ₂=1, O ₃=6 mapping.

Table 2 Mapping Examples

r	Subclass { the s of selected index k}
		0	{?}
1	{5}
		2	{4}
3	{3}
		4	{2}
5	{1}
		6	{4，5}
7	{3，5}
		8	{3，4}
9	{2，5}
		10	{2，4}

11	{2，3}
		12	{1，5}
13	{1，4}
		14	{1，3}
15	{1，2}

The mapping of above-mentioned subclass (ordering) allows fast mapping to conciliate mapping, even is described below, and does not need whole table.Have again, certainly, possibly make and at first find s according to Laian County described below permutation table equally ₀=1, follow by s ₀The subclass of=1+1, the rest may be inferred, up to s ₀Till all subclass of=N-Q+1, therefore, the formula below correspondingly changing.

Continue the described arrangement of table 2, if s<sub >k</sub>=x, it has same index s<sub >j</sub>All subclass after, j＜k and x＜s are wherein arranged<sub >k</sub>≤N.The number of these subclass equals<maths num=" 0010 "><![CDATA[<math><mrow><mfenced open=' (' close=') '><mtable><mtr><mtd><mi>N</mi><mo>-</mo><mi>x</mi></mtd></mtr><mtr><mtd><mi>Q</mi><mo>-</mo><mi>k</mi></mtd></mtr></mtable></mfenced><mo>,</mo></mrow></math>]]></maths>This be because take out in need be from x+1 to N Q-k index (l=k, k+1 ..., Q-1).At s<sub >k</sub>When having its highest probable value, i.e. s<sub >k</sub>During=N-Q+k+1, there is not higher s certainly<sub >k</sub>The subclass of value.In that event, N-s<sub >k</sub>=Q-k-1, still<maths num=" 0011 "><![CDATA[<math><mfenced open=' (' close=') '><mtable><mtr><mtd><mi>Q</mi><mo>-</mo><mi>k</mi><mo>-</mo><mn>1</mn></mtd></mtr><mtr><mtd><mi>Q</mi><mo>-</mo><mi>k</mi></mtd></mtr></mtable></mfenced></math>]]></maths>It or not mathematical definition.Therefore, can contracted notation through definition expansion binomial coefficient < maths num=" 0012 "/>:

Now, through estimate and accumulative total have the institute of higher index value might the subclass number and add skew O _j, be easy to calculate for given m _jThe r of the subclass of index.The mapping machine is input with subclass

, and formula is created digital r below using in scope

:

Wherein, obtain O by formula (6) _jCan use

individual bit to transmit digital r now to Node B.

Correspondingly, the present invention helps using mathematic(al) representation to calculate r in fact, and does not need when the subclass of subband index will send to the base station, all to store or the generation table at every turn.

The present invention also helps in receiver (base station), to be equal to or roughly to be equal to easily and from receive bit sequence, extracts r, and mapping algorithm is originally separated in explanation below.The task of separating the mapping machine is from receive bit sequence, to extract r, detects the subclass that j also produces index again.This divides two steps to carry out, and is described as follows:

Step 1:

Givenly satisfy O _jThe maximum integer j of≤r.Find j and calculate r ':

r′＝r-O _j.

Step 2:

Digital r ' in given j and the step 1 is provided with Q=m _j, find index through carrying out following algorithm Given with the common software coding form:

An example that shows specific algorithm below:

The mapping machine is conciliate the mapping machine needs binomial coefficient $\left(\begin{array}{c}n\\ k\end{array}\right)$ N=0 ..., N-1 and k=0,1 ..., max{m _jCarry out aforesaid operations.These coefficients can precomputations and are stored in the table.

As stated, the present invention proposes the effective ways that a kind of particular subset that finds the subband index that will send to the base station is represented.The invention allows for the effective ways that in receiver, recover r.

Claims (24)

1. one kind is sent the method that subband identifies from first transceiver to second transceiver in wireless data communication system, wherein the communication resource is divided into frequency subband (n ₁..., n _N), constitute sets of subbands, and said first transceiver sends said frequency subband subclass (m to said second transceiver ₁..., m _Q) sign, it is characterized in that said method comprises:

Set up the subclass group, wherein each subclass (m in every group ₁..., m _Q) comprise the sign of same number subband, and subclass (m in the group ₁..., m _Q) sorted; And

First transceiver sends the said subclass (m of sets of subbands to second transceiver ₁..., m _Q) sign, the sign of wherein said subclass is to represent through sign of sending said subclass place group and the position of said subclass in said group.

2. method according to claim 1 is characterized in that, with the subclass that digital r representes said subband, confirms r by the sign and the position of said subclass in said group of said subclass place group.

3. method according to claim 2 is characterized in that, confirms said group id by the group particular offset.

4. according to claim 2 or 3 described methods, it is characterized in that, with (1 ..., N) said subband represented in index, said method further comprises:

A) the subclass m in will organizing ₁..., m _QOrdering, minimum index m in the at first arrangement group ₁Next subclass with the highest probable value n is the subclass of n-1 for minimum index, and the rest may be inferred, up to minimum index be all subclass of 1 till;

B) i=1 is set;

C) to minimum index m ₁All subclass that equate sort, if perhaps i＞1, to minimum index m ₁..., m _iAll subclass that all equate sort, so that first subclass is minimum residue index m _I+1Having the subclass of high probable value, is that minimum residue index has time the subclass of high probable value then, and the like, be m up to minimum residue index _iTill all subclass of+1; And

D) i=i+1 is set, and repeats step c) till i=Q-1.

5. method according to claim 2 is characterized in that, r notifies through the symbol sebolic addressing that carries expression r.

6. method according to claim 5 is characterized in that, said symbol sebolic addressing is binary system, ternary or the decimal representation of r.

7. method according to claim 1 is characterized in that, before said grouping, N index is arranged arbitrarily.

8. method according to claim 1 is characterized in that, Q is any in J the different integers, 0≤Q≤N-1, and each Q value is used different skews.

9. method according to claim 1 is characterized in that, can in sending CQI and/or PVI and/or other any subband special parameters, use the method for the said subband sign of said transmission.

10. method according to claim 1 is characterized in that, said subclass representes to have the best Q subband of optimal CQI value.

11. method according to claim 1 is characterized in that, said first transceiver is a portable terminal, and said second transceiver is the base station.

12. one kind is sent the system that subband identifies from first transceiver to second transceiver, wherein the communication resource is divided into frequency subband (n in wireless data communication system ₁..., n _N), constitute sets of subbands, and said frequency subband subclass (m ₁..., m _Q) sign be configured to send to said second transceiver from said first transceiver, it is characterized in that said system comprises:

Set up the device of subclass group, wherein each subclass (m in every group ₁..., m _Q) comprise the sign of same number subband, and subclass (m in the group ₁..., m _Q) sorted; With

First transceiver sends said subclass (m to second transceiver ₁..., m _Q) the device of sign, the sign of wherein said subclass is to represent through sign of sending said subclass place group and the position of said subclass in said group.

13. system according to claim 12 is characterized in that, the subclass of said subband is configured to represent with digital r, and r by said subclass group id and in said group the position of subclass confirm.

14. system according to claim 13 is characterized in that, said group id is confirmed by the group particular offset.

15. according to claim 13 or 14 described systems, it is characterized in that, said subband usefulness (1 ..., N) index, said system further comprises:

A) will organize in subclass m ₁..., m _QThe device of ordering, minimum index m in the at first arrangement group ₁Next subclass with the highest probable value n is the subclass of n-1 for minimum index, and the like, up to minimum index be all subclass of 1 till;

B) device of i=1 is set;

C) to minimum index m ₁All subclass that equate sort, if perhaps i＞1, to minimum index m ₁..., m _iThe device that all subclass that all equate sort is so that first subclass is minimum residue index m _I+1Having the subclass of high probable value, is that minimum residue index has time the subclass of high probable value then, and the rest may be inferred, is m up to minimum residue index _iTill all subclass of+1; With

D) device and the repeating step c of i=i+1 are set) device till i=Q-1.

16. system according to claim 13 is characterized in that, r notifies through the symbol sebolic addressing that carries expression r.

17. system according to claim 16 is characterized in that, said symbol sebolic addressing is binary system, ternary or the decimal representation of r.

18. system according to claim 12 is characterized in that, before said grouping, N index is arranged arbitrarily.

19. system according to claim 12 is characterized in that, Q is any in J the different integers, 0≤Q≤N-1, and each Q value is used different skews.

20. system according to claim 12 is characterized in that, can in sending CQI and/or PVI and/or other any subband special parameters, use the method for the said subband sign of said transmission.

21. system according to claim 12 is characterized in that, said subclass representes to have the best Q subband of optimal CQI value.

22. one kind is extracted in wireless data communication system from the method for first transceiver to the subband sign of second transceiver transmission, wherein the communication resource is divided into frequency subband (n ₁..., n _N), constitute sets of subbands, and send said frequency subband subclass (m to said second transceiver from said first transceiver ₁..., m _Q) sign, it is characterized in that said method comprises: in second transceiver,

From received signal, recover the affiliated subclass group id that the subclass that receives is represented, the subclass in wherein said group is sorted; And

Utilize the expression of the said subclass position in said group to recover this subclass, said expression is to be received from said first transceiver.

23. the multi-user's cellular communication system with the communication resource of between first transceiver and second transceiver, communicating by letter at least is characterized in that, said communication system comprises the device that is used for each said method of enforcement of rights requirement 1-11.

24. the multi-user's cellular communication system with the communication resource of between first transceiver and second transceiver, communicating by letter at least is characterized in that, said communication system comprises the device that is used for method described in the enforcement of rights requirement 22.

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