CN101834707A - Method for acquiring channel state information and corresponding communication system - Google Patents

Abstract

The invention relates to a method for acquiring channel state information and a corresponding communication system, which are applied to a system that a base station adopts dual-polarized antenna configuration and the number of the ports of a transmitting antenna is more than 8. In the method, user equipment reports the information of the number of total downlink transmission layers and the indexing information of one or two secondary code words to the base station; the base station acquires the corresponding secondary code word according to the indexing information and the information of the number of total layers after receiving the indexing information and the information of the number of total layers sent by the user equipment; and the base station configures a matrix code word for indicating the current channel state by the base station according to the secondary code word. The invention provides the method for acquiring the channel state information under the configuration of eight or more dual-polarized antennas, which can ensure the very low feedback overhead and improve the system performance.

Description

A kind of method and corresponding communication system that obtains channel condition information

Technical field

The present invention relates to digital communicating field, relate in particular to code word acquisition methods and corresponding communication system under a kind of dual-polarized eight antenna antenna configurations.

Background technology

In long evolving system (LTE:Long Term Evolution), its agreement is Release 8 versions, be called for short the R8 version, the information (CSI:Channel StateInformation) of reflection down physical channel state has three kinds of forms: channel quality indication (CQI:Channels quality indication), pre-coding matrix indication (PMI:Pre-coding Matrix Indicator), order indication (RI:RankIndicator).

CQI is for weighing an index of down channel quality quality.CQI represents with 0～15 integer value in the 36-213 agreement, has represented different CQI grades respectively, and different CQI correspondences modulation system and encoder bit rate (MCS) separately, are divided into 16 kinds of situations, can adopt 4 bit informations to represent.

PMI is meant only under this emission mode of Closed-Loop Spatial Multiplexing, terminal (UE:UserEquipment) tells according to the channel quality that records which type of pre-coding matrix base station (eNB:eNode B) should use to carry out precoding to the PDSCH that issues this UE (Physical Downlink SharedChannel, Physical Downlink Shared Channel) channel.The feedback granularity of PMI can be PMI of whole bandwidth feedback, also can feed back PMI according to subband (subband).

RI is used to describe the number of space independent channel, the order of respective channels response matrix.Under Open-Loop Spatial Multiplexing and Closed-Loop Spatial Multiplexing pattern, need UE feedback RI information, do not need to feed back RI information under other patterns.The sum of ranks number of plies correspondence of channel matrix, so UE promptly is the number of plies of feeding back downlink transmission to base station feedback RI information.

Transport layer is the notion of many antennas " layer " among LTE and the LTE-A, the number of effective independent channel during representation space is multiplexing, and corresponding one by one with antenna port in version 10, wherein antenna port is a logic port in the version 10, the sum of transport layer is exactly RI.In addition, in IEEE802.16m, layer is corresponding with " MIMO stream " notion, has identical physical meaning.

In the LTE system, the feedback of CQI, PMI, RI can be periodic feedback, also can be acyclic feedback.CQI and PMI can send simultaneously, and perhaps CQI, PMI and RI send simultaneously.Wherein, for periodic feedback, if UE does not need to send data, then the CSI of periodic feedback goes control channel (PUCCH:Physical Uplink Control Channel) physically upward with form 2 or 2a or 2b (PUCCH format2/2a/2b) transmission, when if UE need send data, then transmission in the capable physically shared channel (PUSCH:Physical Uplink Shared Channel) of CSI; For the aperiodicity feedback, only on PUSCH, transmit.

Channel related information, i.e. the definition of channel correlation matrix, on cycle regular hour and certain bandwidth, correlation matrix R measures according to following form:

$R=E\left(H_{\mathrm{ij}}^H{H}_{\mathrm{ij}}\right)$

H wherein _IjThe correlated channels matrix of representing j subcarrier correspondence of i OFDM symbol period, its size are Nt*Nr, and wherein, Nt is the number of transmitting antenna, and Nr is the number of reception antenna.Described bandwidth both can be a full bandwidth (wideband), also can be (subband) of subband.

For N _t=2, in the time of promptly 2 days transmitting antennas

$R=\left(\begin{array}{cc}r11& \mathrm{<figure-callout\; id="12"\; label="r"\; filenames="HSA00000088847900011.png"\; state="\{\{state\}\}">r</figure-callout>}12\\ \mathrm{conj}\left(r12\right)& \mathrm{<figure-callout\; id="22"\; label="r"\; filenames="HSA00000088847900012.png"\; state="\{\{state\}\}">r</figure-callout>}22\end{array}\right)$

For N _t=4, in the time of promptly 4 days transmitting antennas

$R=\left(\begin{array}{cccc}r11& r12& r13& r14\\ \mathrm{conj}\left(r12\right)& r22& r23& r24\\ \mathrm{conj}\left(r13\right)& \mathrm{conj}\left(r23\right)& r33& r34\\ \mathrm{conj}\left(r14\right)& \mathrm{conj}\left(r24\right)& \mathrm{conj}\left(r34\right)& r44\end{array}\right)$

For N _t=8, in the time of promptly 8 days transmitting antennas

$R=\left(\begin{array}{cccccccc}{r}_{11}& r_{12}& r_{13}& r_{14}& r_{15}& r_{16}& r_{17}& r_{18}\\ \mathrm{conj}\left(r_{12}\right)& r_{22}& r_{23}& r_{24}& r_{25}& r_{26}& r_{27}& r_{28}\\ \mathrm{conj}\left(r_{13}\right)& \mathrm{conj}\left(r_{23}\right)& r_{33}& r_{34}& r_{35}& r_{36}& r_{37}& r_{38}\\ \mathrm{conj}\left(r_{14}\right)& \mathrm{conj}\left(r_{24}\right)& \mathrm{conj}\left(r_{34}\right)& r_{44}& r_{45}& r_{46}& r_{47}& r_{48}\\ \mathrm{conj}\left(r_{15}\right)& \mathrm{conj}\left(r_{25}\right)& \mathrm{conj}\left(r_{35}\right)& \mathrm{conj}\left(r_{35}\right)& r_{55}& r_{56}& r_{57}& r_{58}\\ \mathrm{conj}\left(r_{16}\right)& \mathrm{conj}\left(r_{26}\right)& \mathrm{conj}\left(r_{36}\right)& \mathrm{conj}\left(r_{46}\right)& \mathrm{conj}\left(r_{56}\right)& r_{66}& r_{67}& r_{68}\\ \mathrm{conj}\left(r_{17}\right)& \mathrm{conj}\left(r_{27}\right)& \mathrm{conj}\left(r_{37}\right)& \mathrm{conj}\left(r_{47}\right)& \mathrm{conj}\left(r_{57}\right)& \mathrm{conj}\left(r_{58}\right)& r_{77}& r_{78}\\ \mathrm{conj}\left(r_{18}\right)& \mathrm{conj}\left(r_{28}\right)& \mathrm{conj}\left(r_{38}\right)& \mathrm{conj}\left(r_{48}\right)& \mathrm{conj}\left(r_{58}\right)& \mathrm{conj}\left(r_{68}\right)& \mathrm{conj}\left(r_{78}\right)& r_{88}\end{array}\right)$

Conj (.) represents complex conjugate.Number on the channel correlation matrix diagonal is a real number as can be seen, and off-diagonal number is a plural number.Because correlation matrix R is the conjugation symmetrical matrix, therefore only need the upper triangular matrix of feedback R matrix.

Another method promptly is rotated the LTE code book with the correlation matrix information of channel in the prior art, i.e. the mathematic(al) manipulation of R8 version code book:

$C=R^{\frac{1}{2}}\&times;C_{R8}$

Wherein C represents C _R8The code book that obtains after the rotation, R=H ^HH, H are dimension N _r* N _tChannel matrix, N _rBe reception antenna number, N _tBe number of transmit antennas.

Owing to comprised the distributed intelligence of characteristic vector in the channel correlation matrix information.Also can quantize at the bigger regional emphasis of distribution probability at the distribution probability of characteristic vector after code word in the code book is rotated, quantified precision is further improved.

Advanced long-term evolution system (LTE-A:Long Term EvolutionAdvanced) as the evolution standard of LTE needs to support bigger system bandwidth (reaching as high as 100MHz), and need to improve the spectrum efficiency of average spectral efficiency (ase) and Cell Edge User, its agreement is Release 10 versions, be called for short the R10 version, for this reason, the LTE-A system has introduced a lot of new technologies: the high-order multiple-input and multiple-output (MIMO:Multiple Input Multiple Output) that (1) is descending, the LTE system descending is supported 4 antenna transmission at most, and the introducing of high-order mimo makes the LTE-A system descending support the transmission of 8 antennas at most, and then the dimension of channel state matrix increases; (2) cooperative multipoint transmission (CoMP:Coordinatedmultiple point transmission), this technology is exactly to utilize the cooperation transmission of a plurality of sub-districts transmitting antenna, and UE may need to feed back the channel condition information of a plurality of sub-districts so.

When 8 antennas or more antennas, main application form is a dual polarized antenna, adopts dual polarized antenna to help reducing spacing between the antenna, helps the layout of antenna.

Use many antennas at transmitting terminal (eNB), can take the mode of spatial reuse to improve transmission rate, the different data of the i.e. emission of different antennae position on the identical running time-frequency resource of transmitting terminal, (UE) also uses many antennas at receiving terminal, can under single user's situation, the resource of all antennas all be distributed to same user, this transmission form is called Single User MIMO (SU-MIMO), also can give different user with the resource allocation in different antennae space under multi-user's situation in addition, this transmission form is called multiuser MIMO (MU-MIMO).Under single transmission mode, eNB can dynamically select the transmission of descending SU-MIMO or the transmission of MU-MIMO according to the channel condition information that reports, and is referred to as SU/MU MIMO and dynamically switches.

The general processing procedure that once Single User MIMO and multiuser MIMO dynamically switch transmission mode is described below:

At first, transmitting terminal sends pilot tone to user terminal, be used for user terminal test down channel state, user terminal is estimated down channel according to the pilot frequency information that receives, user terminal is determined the form of feeding back channel state information, and reporting status information of channel, then the channel condition information that is reported by the eNB basis, dynamically select the transmission of descending SU-MIMO or the transmission means of MU-MIMO, and communicate according to the transmission means of selecting.

Adopt the system of dual polarized antenna configuration for LTE-A system or other, dual-polarized eight antennas or more antenna will become main antenna configurations.In this condition, need to use a kind of low expense, high performance code book, be used for the feedback of channel condition information, improve the performance of system.

Summary of the invention

The technical problem to be solved in the present invention provides the method for obtaining channel condition information under a kind of dual-polarized eight antennas or the more antenna configurations, can guarantee the enough low feedback overhead and the performance of system.

For solving the problems of the technologies described above, the invention provides a kind of method of obtaining channel condition information, be applied to the base station and adopt dual polarized antenna configuration and transmitting antenna port number more than or equal to 8 system, comprising:

Subscriber equipment reports the base station with the total number of plies information of downlink transfer and the index information of one or two secondary code words;

After the index information and total number of plies information that described subscriber equipment sends received in described base station, according to the secondary code words of described index information and total number of plies information acquisition correspondence;

Described base station constructs the matrix code word that is used to indicate current channel condition according to described secondary code words.

Further,

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station, described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word in the following manner, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& u(i,j)\\ -u(i,j)& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

Further,

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station, described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word in the following manner, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& 0\\ 0& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

Further,

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station, the base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct the matrix code word C of indication current channel condition by following formula _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& u_2(i,j^{\&prime;})\\ -u_1(i,j)& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂Another secondary code words that (i, j ') expression obtains, i, j ' are this secondary code words u ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

Further,

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station, the base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct the matrix code word C of indication current channel condition by following formula _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& 0\\ 0& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂Another secondary code words that (i, j ') expression obtains, i, j ' are this secondary code words u ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, and the described index information of reporting base station is the index of a secondary code words, comprises the one-level index i and the secondary index j of this secondary code words, i, j are the integer more than or equal to 0;

Described base station finds this secondary code words according to index i, j and δ from default second level code book, wherein, and δ=v/2.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of a secondary code words, the one-level index i and the secondary index j that comprise this secondary code words, this secondary code words is obtained by an one-level code word expansion, this index i still is the index of this one-level code word, and i, j are the integer more than or equal to 0;

Described base station is according to index i and δ, finds this one-level code word from default first order code book, and carry out extended arithmetic according to this one-level code word and index j then and obtain this secondary code words, wherein, δ=v/2.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', i, j and j ' are the integer more than or equal to 0;

Described base station finds this first secondary code words according to index i, j and δ from default second level code book, according to index i, j ' and δ, find this second secondary code words from this second level code book, wherein, and δ=v/2.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', these two secondary code words are obtained by same one-level code word expansion, and this index i still is the index of this one-level code word, i, j and j ' are the integer more than or equal to 0;

Described base station is according to index i and δ, from default first order code book, find this one-level code word, carry out extended arithmetic according to this one-level code word and index j then and obtain this first secondary code words, carry out extended arithmetic according to this one-level code word and index j ' and obtain this second secondary code words, wherein δ=v/2.

Further,

This method is used between base station and subscriber equipment adopting multi-user's multiple-input and multiple-output (MIMO) transmission mode, or Single User MIMO and multiuser MIMO dynamically switch transmission mode.

Further,

Described one or two secondary code words one or two secondary code words that to be described subscriber equipment obtain according to the down channel state matches of two polarised directions.

Correspondingly, communication system provided by the invention comprise subscriber equipment and adopt the dual polarized antenna configuration and the transmitting antenna port number more than or equal to 8 base station, wherein:

Described subscriber equipment is used for the total number of plies information of downlink transfer and the index information of one or two secondary code words are reported the base station;

Described base station is used for after receiving the index information and total number of plies information that described subscriber equipment sends, according to the secondary code words of described index information and total number of plies information acquisition correspondence, and construct the matrix code word that is used to indicate current channel condition according to described secondary code words.

Further,

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station;

Described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word by following formula, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& u(i,j)\\ -u(i,j)& u(i,j)\end{array}\right]$

Perhaps

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& 0\\ 0& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

Further,

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station;

Described base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct the matrix code word C of indication current channel condition by following formula _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& u_2(i,j^{\&prime;})\\ -u_1(i,j)& u_2(i,j^{\&prime;})\end{array}\right]$

Perhaps

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& 0\\ 0& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂Another secondary code words that (i, j ') expression obtains, i, j ' are this secondary code words u ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, and the described index information of reporting base station is the index of a secondary code words, comprises the one-level index i and the secondary index j of this secondary code words, i, j are the integer more than or equal to 0; Described base station finds this secondary code words according to index i, j and δ from default second level code book, wherein, and δ=v/2; Perhaps

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of a secondary code words, the one-level index i and the secondary index j that comprise this secondary code words, this secondary code words is obtained by an one-level code word expansion, this index i still is the index of this one-level code word, and i, j are the integer more than or equal to 0; Described base station is according to index i and δ, finds this one-level code word from default first order code book, and carry out extended arithmetic according to this one-level code word and index j then and obtain this secondary code words, wherein, δ=v/2.

Further,

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', i, j and j ' are the integer more than or equal to 0; Described base station finds this first secondary code words according to index i, j and δ from default second level code book, according to index i, j ' and δ, find this second secondary code words from this second level code book, wherein, and δ=v/2; Perhaps

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', these two secondary code words are obtained by same one-level code word expansion, and this index i still is the index of this one-level code word, i, j and j ' are the integer more than or equal to 0; Described base station is according to index i and δ, from default first order code book, find this one-level code word, carry out extended arithmetic according to this one-level code word and index j then and obtain this first secondary code words, carry out extended arithmetic according to this one-level code word and index j ' and obtain this second secondary code words, wherein δ=v/2.

The method of the invention, adopt dual polarized antenna configuration and antenna number more than or equal to 8 system for LTE-A etc., by the index information of feedback with one or two secondary code words of current channel condition coupling, guaranteed the precision of channel condition information feedback, be the codewords indexes of code book under the monopolarization channel owing to what feed back simultaneously, construct matrix code word under the dual polarization channel with one or two code word, neither directly feed back the index of the matrix code word under the dual polarization channel, solve the excessive problem of feedback overhead.Can be applied to SU/MU and dynamically switch obtaining of channel condition information under the transmission meanss such as transmission means, MU-MIMO transmission means.

Description of drawings

Fig. 1 is the flow chart of embodiment one method;

Fig. 2 is the flow chart of embodiment two methods;

Fig. 3 is the flow chart of embodiment three methods;

Fig. 4 is the flow chart of embodiment four directions method;

Fig. 5 is the flow chart of embodiment five methods.

Fig. 6 is the flow chart of embodiment six methods.

Embodiment

In order to obtain higher peaks spectrum efficient, in the LTE-A system, descending needs are supported 8 transmitting antennas, and the dual polarized antenna configuration will become main mode.On the one hand, the feedback control signaling of channel information need keep enough little expense, so need the form of the code book of consideration dual polarized antenna; On the other hand, the feeding back channel state information of channel information need be considered feedback accuracy, thereby to the better support of MU-MIMO and COMP, guarantees that new technology has the acceptable performance, so need to consider the multi-stage codebooks structure.Comprehensive two aspects of the present invention propose a solution.

Under the monopolarization channel condition, UE is reported to the base station with the index of the code word that the channel status that measures matches, this code word can be the code word in the second level code book of a two-stage codebook group, is called secondary code words, and this code word has one-level index and secondary index.Normally, a plurality of code words in the second level code book of this two-stage codebook group are to carry out extended arithmetic according to certain code word in the first order code book (being called the one-level code word) to obtain, and the one-level index of this secondary code words is the index of this one-level code word in this first order code book simultaneously.Therefore, under the dual polarization channel condition, can be by one (strong correlation channel condition under) or the index information of two secondary code words (weak correlated channels condition under) of feedback with the current channel condition coupling, guaranteed the precision of channel condition information feedback, be the codewords indexes of code book under the monopolarization channel owing to what feed back simultaneously, construct matrix code word under the dual polarization channel with one or two code word, feedback overhead is very little.

Embodiment one

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of eight antennas that adopt the dual polarized antenna configuration, and as shown in Figure 1, this method comprises:

Step 11, subscriber equipment (UE) reports base station (being called eNB in LTE-A) with index information and total number of plies information v of a secondary code words, and this index information comprises the one-level index i and the secondary index j of this secondary code words, and i, j are the integer more than or equal to 0;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, and this secondary code words can be carried out extended arithmetic by this one-level code word and be obtained.Under the strong correlation channel condition, can indicate two channel statuss on the polarised direction with this secondary code words.

Step 12, described base station are according to the index information i that receives, j and total number of plies information v find this secondary code words from the second level code book of default two-stage codebook group.

This two-stage codebook group comprises a first order code book and a second level code book, and i is the index of one-level code word in the first order code book, also is first index of secondary code words in the code book of the second level simultaneously, and j is second index of code word in the code book of the second level.Code book and code word that base station and terminal are used are appointed in advance.

Particularly, the base station is determined a code word CMat according to i, j and v by the mode of tabling look-up from default second level code book _Ij ^δ, CMat _Ij ^δBe that a size is N _tThe complex matrix of * δ, wherein, N _tBe positive integer, the transmitting antenna port number of expression base station; δ=v/2 also is the index of code word in the first order and the second level code book; NB ₁, NB ₂For greater than 1 integer, NB ₁Be the bit number of representing the index needs of one-level code word with binary sequence, NB ₂Be the bit number of representing the index needs of secondary code words with binary sequence, NB ₁+ NB ₂Be the bit number of representing the index needs of one-level code word and secondary code words with binary sequence, NB ₁, NB ₂Can be provided with in conjunction with precision needs and codebook size.As can be seen, the feedback overhead and the single polarization condition of present embodiment needs are similar.

As shown in table 1 with i, j and δ as the example of the second level code book of index:

Table 1

In the table, δ=1 o'clock, CMat _Ij ^δSize is (Nt/2) * 1.N _t=8 o'clock, CMat _Ij ^δBe 4 * 1 complex vector located, N _tAlso can get other values, as N _t=16, this moment CMat _Ij ^δBe 8 * 1 complex vector located.Go up the code word in the code book of the second level in the table in addition, for some i, j value, CMat _Ij ^δCan be default, promptly may not use.

In the present embodiment, the base station can also find a code word C by the mode of tabling look-up according to i and v from the first order code book of this default two-stage codebook group _I(N _t, v, i), C _I(N _t, v, i code word of correspondence when being δ in the first order code book=v/2 i), C _I(N _t, v also is that size is N i) _tThe complex matrix of * δ.First order code book is known, and the code book that can provide in agreement for example has following form:

$C_I(N_t,v=2,i)=\left[\begin{array}{cc}w\left(i\right)& w\left(i\right)\\ -w\left(i\right)& w\left(i\right)\end{array}\right]$

$i=\mathrm{0,1},...,2^{{\mathrm{NB}}_1}-1$

Wherein, w (i) is (N _t/ 2) complex matrix * 1.

The code word of δ=1 can be based on the code word and a known codebook of δ in the first order code book=1 in the code book of the present embodiment second level, carries out that twiddle operation among the embodiment three or compression and twiddle operation obtain; Also can be based on the code word of δ in the first order code book=1, carry out phase place among the embodiment four and adjust that computing obtains; Also can adopt the mode among the embodiment five, promptly based on a part code word of δ=1 in the first order code book part code word of correlated channels (as be suitable for) and a known codebook, be rotated the part code word that computing or compression and twiddle operation obtain δ=1 in this second level code book, based on all the other code words of δ=1 in the first order code book part code word of non-correlation channel (as be suitable for), carry out phase place and adjust all the other code words that computing obtains δ=1 in this second level code book.Concrete compute mode will be described in detail among each embodiment below.Some code word in the code book of the second level can be default.

Code word CMat in the code book of the second level _Ij ^δCan quantize a channel status on the polarised direction, when system adopted the dual polarized antenna configuration, in order to reflect the channel status of dual polarized antenna configuration, the base station can utilize this code word further to construct a matrix code word.At the transmitting antenna port number is N _t, during total number of plies v=2, the base station can construct this matrix code word that is used to indicate current channel condition (dual polarization channel) by following formula:

$C_{\mathrm{II}}(N_t=8,v=2,i,j)=\left[\begin{array}{cc}u(i,j)& u(i,j)\\ -u(i,j)& u(i,j)\end{array}\right]---\left(1\right)$

Perhaps

$C_{\mathrm{II}}(N_t=8,v=2,i,j)=\left[\begin{array}{cc}u(i,j)& 0\\ 0& u(i,j)\end{array}\right]---\left(2\right)$

In two formulas:

$u(i,j)={\mathrm{CMat}}_{\mathrm{ij}}^{\mathrm{\&delta;}=1},$ $i=\mathrm{0,1},...,2^{{\mathrm{NB}}_1}-1,$ $j=\mathrm{0,1},...,2^{{\mathrm{NB}}_2}-1$

Carry out the result of emulation and checking according to the dual polarization Channel Models, formula (1) preferred application is the situation of 45 degree in the angle of dual polarized antenna, formula (2) preferred application is the situation of 0 degree in the angle of dual polarized antenna, and this angle refers to the angle of some polarised directions of dual polarized antenna and horizontal direction.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration to have the system of more antennas as 16 antennas, searches the method for code word in the time of can adopting above-mentioned 8 antennas equally and constructs the method that is suitable for the matrix code word that dual polarized antenna disposes with this code word.

Embodiment two

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of eight antennas that adopt the dual polarized antenna configuration, and as shown in Figure 2, this method comprises:

Step 21, UE reports the base station with index information and total number of plies information v of two secondary code words, and described index information comprises the one-level index i and the secondary index j of a secondary code words, and the index i and the j ' of another secondary code words;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, and these two secondary code words all are to carry out extended arithmetic by this one-level code word to obtain, and can indicate two channel statuss on the polarised direction respectively under weak correlated channels condition.

Step 22, the i that described base station basis is received, j and v, and i, j ' and v respectively find a secondary code words from the second level code book of this default two-stage codebook group.

This two-stage codebook group comprises a first order code book and a second level code book, i is the index of one-level code word in the first order code book, also be first index of these two secondary code words in the code book of the second level simultaneously, j is second index of a secondary code words in the code book of the second level, and j ' is second index of another secondary code words in the code book of the second level.Code book and code word that base station and terminal are used are appointed in advance.

Particularly, the base station is according to i, and j ', v search a code word CMat from the code book of the second level _{Ij '} ^δWith according to i, j, v search a code word CMat from the code book of the second level _Ij ^δMethod be identical, for no other reason than that the value of j ' is different with j, the code word difference that finds, according to i, j, v search a code word from the code book of the second level method is identical with embodiment one, CMat _Ij ^δ=1And CMat _{Ij '} ^δAll represent a complex matrix, size is (N _t/ 2) * 1, δ=υ/2.In the present embodiment, the base station can also find a code word C by the mode of tabling look-up according to i and v from the first order code book of this default two-stage codebook group _I(N _t, v, i), with embodiment one.

Base station lookups to two a code word CMat _Ij ^δAnd CMat _{Ij '} ^δAfter, be N at the transmitting antenna port number _t, during total number of plies v=2, can construct a matrix code word that is used to indicate current channel condition (dual polarization channel) by one of following formula:

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& u_2(i,j^{\&prime;})\\ -u_1(i,j)& u_2(i,j^{\&prime;})\end{array}\right]---\left(3\right)$

Perhaps

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& 0\\ 0& u_2(i,j^{\&prime;})\end{array}\right]---\left(4\right)$

In two formulas,

$u_1(i,j)={\mathrm{CMat}}_{\mathrm{ij}}^{\mathrm{\&delta;}=1},$ $u_2(i,j^{\&prime;})={\mathrm{CMat}}_{i{j}^{\&prime;}}^{\mathrm{\&delta;}=1}.$

$i=\mathrm{0,1},...,2^{{\mathrm{NB}}_1}-1,$ $j=\mathrm{0,1},...,2^{{\mathrm{NB}}_2}-1,$ $j^{\&prime;}=\mathrm{0,1},...,2^{{\mathrm{NB}}_2}-1$

Carry out the result of emulation and checking according to the dual polarization Channel Models, formula (3) preferred application is the situation of 45 degree in the angle of dual polarized antenna, second way preferred application is the situation of 0 degree in the angle of dual polarized antenna, and this angle refers to the angle of some polarised directions of dual polarized antenna and horizontal direction.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration to have the system of more antennas as 16 antennas, searches the method for two code words in the time of can adopting above-mentioned 8 antennas equally and constructs the method that is suitable for the matrix code word that dual polarized antenna disposes with these two code words.

In following examples three to five, the base station is to find an one-level code word earlier according to index i and v, and then according to index j this one-level code word is carried out extended arithmetic, obtains this second code word.Being used for that the one-level code word is carried out the method that extended arithmetic obtains second code word has a lot, and following examples have just provided a kind of mode of extended arithmetic respectively, are not intended to limit the invention.

Embodiment three

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of 8 antennas that adopt the dual polarized antenna configuration, and as shown in Figure 3, this method comprises:

Step 31, subscriber equipment (UE) reports base station (being called eNB in LTE-A) with index information and total number of plies information v of a secondary code words, and this index information comprises the one-level index i and the secondary index j of this secondary code words, and i, j are the integer more than or equal to 0;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, and this secondary code words can be carried out extended arithmetic by this one-level code word and be obtained.

Step 32, the base station finds an one-level code word according to i that receives and v from default first order code book, be designated as first code word, from a known codebook of presetting, find one the 3rd code word according to j and v, spin matrix with this first code word correspondence is rotated to the 3rd code word or to one the 4th code word that obtains after the compression of the 3rd code word, obtain a secondary code words, be designated as second code word.

Need to prove,, the code word of first order code book has been carried out further quantification by above-mentioned twiddle operation or compression and twiddle operation.When j gets different values, calculate second code word of each first code word correspondence in the first order code book by present embodiment, just can form the second level code book of this first order code book correspondence.Present embodiment adopts the mode of computing can save the storage resources that is used to preserve second level code book.

In one example, above-mentioned default known codebook (being designated as code book C) can be this first order code book (being designated as code book A), also can be other given code book of agreement.The 3rd code word that finds from code book C according to j and v is designated as CWC (j), the NB of correspondence when CWC (j) is δ among the code book C=v/2 _CJ code word in the individual code word, v=2 in the present embodiment.The compression that CWC (j) is carried out earlier obtains the computing of the 4th code word (being designated as CWB (j)) and describes by following formula:

CWB(j)＝MatCmprs(j)·CWC(j) (5)

Wherein,

NB _CFor greater than 1 positive integer, can be according to precision setting; Condensation matrix MatCmprs (i) is a diagonal matrix, and size is N _t* N _t, N _tBe positive integer, the transmitting antenna port number of expression base station.

Wherein:

α is a constant, the expression compression ratio, and promptly the compression degree in a code book space is an arithmetic number, 0≤α≤1; β represents the absolute value of first element of code word CWC (j).Need to prove that condensation matrix MatCmprs (i) is not limited to the above-mentioned concrete form that provides, and also can adopt other forms of matrix.

Further, the 4th code word CWB (j) is rotated obtains second code word and (be designated as CMat _Ij ^δ=1), this twiddle operation is described by following formula:

${\mathrm{CMat}}_{\mathrm{ij}}^{\mathrm{\&delta;}=1}=\mathrm{MatRot}\left(i\right)\&CenterDot;\mathrm{CWB}\left(j\right)---\left(6\right)$

Wherein,

NB ₁And NB _CFor greater than 1 integer, NB ₁The number of code word in the expression first order code book, NB _CThe number of code word among the expression code book C; Spin matrix MatRot (i) is the function of CW1 (i), and for example: MatRot (i) can be unitary matrice [CW1 (i) Q that obtains according to CW1 (i) _{CW1 (i)} ^⊥] or unitary matrice [conj (CW1 (i)) O _{CW1 (i)} ^⊥], conj (CW1 (i)) expression is got conjugation, O to CW1 (i) _{CW1 (i)} ^⊥The N of expression and CW1 (i) quadrature _T-1 column vector, N _TBe positive integer, the transmitting antenna port number of expression base station.

δ=1 o'clock, CW1 (i) is row, MatRot (i)=HH (η-CW1 (i)).HH represents the Household conversion,

Be [1 00 0] ^TTwiddle operation the code word among the one code book B can be rotated to code word among the code book A around, the channel status of its reflection is further quantized.Need to prove that spin matrix MatRot (i) is not limited to the above-mentioned concrete form that provides, also can adopt other matrixes that conversion obtains according to CW1 (i).

To i, j, each value combination of δ=1, CWC (j) and CW1 (i) above-mentioned compression of enforcement and twiddle operation according to correspondence can obtain a CMat _Ij ^δ=1, CMat _Ij ^δ=1Size is

These CMat _Ij ^δ=1The code word that just can form δ=1 in the second level code book of this first order code book correspondence.

In another example, each code word among the code book C is carried out above-mentioned compaction algorithms, the code book that the code word that obtains is formed is designated as code book B, code book B preserves in the base station as above-mentioned default known codebook, obtain a change example like this with above-mentioned example, the 3rd code word that to be the base station find from code book B according to j and v is the code word CWB (j) of δ among the code book B=1, and afterwards, only need be rotated computing to the 3rd code word CWB (j) just can obtain the second code word CMat _Ij ^δ=1, do not need to carry out again compaction algorithms.Similarly, in this example, to i, j, each value combination of δ=1 is implemented above-mentioned twiddle operation according to the CWB (j) and the CW1 (i) of correspondence, can obtain a CMat _Ij ^δ=1, these CMat _Ij ^δ=1The code word that just can form δ=1 in the second level code book of this first order code book correspondence.

In the present embodiment, the base station can utilize second code word that obtains further to construct a matrix code word.At the transmitting antenna port number is N _t, during total number of plies v=2, the mode that this matrix code word is constructed in the base station is identical with embodiment one, repeats no more here.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration, have the system of more antennas, method by searching and calculate second code word and constructing the matrix code word that is suitable for the dual polarized antenna configuration with this code word in the time of can adopting above-mentioned 8 antennas equally as 16 antennas.

It may be noted that present embodiment has provided by a known codebook being carried out compress afterwards earlier the method that the mode of rotating (or rotation) obtains second code word, obtains above-mentioned second code word but the present invention can also carry out rotating the mode of afterwards compressing earlier to a known codebook.

Embodiment four

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of 8 antennas that adopt the dual polarized antenna configuration, and as shown in Figure 4, this method comprises:

Step 41, subscriber equipment (UE) reports base station (being called eNB in LTE-A) with index information and total number of plies information v of a secondary code words, and this index information comprises the one-level index i and the secondary index j of this secondary code words, and i, j are the integer more than or equal to 0;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, and this secondary code words can be carried out extended arithmetic by this one-level code word and be obtained.

Step 42, the base station finds an one-level code word according to i that receives and v from default first order code book, be designated as first code word, with the value substitution of j is after a phase place of parameter is adjusted matrix with j, this phase place adjustment matrix and this first code word are multiplied each other, obtain a secondary code words, be called second code word.

When j gets different values, phase place by present embodiment is adjusted second code word that operation method calculates each first code word correspondence in the first order code book, the second level code book that also can form this first order code book correspondence adopts calculation mode can save the storage resources that is used to preserve second level code book.

To be designated as CW1 (i), another index δ=v/2 of this code word, v=2 in the present embodiment according to first code word that i and v find from first order code book.Each element of the first code word CW1 (i) is carried out the phase place adjustment to be obtained second code word and (is designated as CMat _Ij ^δ=1), this phase place is adjusted computing and is described by following formula:

${\mathrm{CMat}}_{\mathrm{ij}}^{\mathrm{\&delta;}=1}=\mathrm{MatPhsAdj}\left(j\right)\&CenterDot;\mathrm{CW}1\left(i\right)---\left(7\right)$

Wherein,

NB ₁, NB ₂For greater than 1 integer, NB ₁The number of the code word that δ is identical in the expression first order code book, NB ₂Can be provided with in conjunction with precision needs and codebook size.

It is diagonal matrix that phase place is adjusted matrix M atPhsAdj (j):

Wherein,

Be to correspond respectively to the 1st to N of CW1 (i) _tThe adjustment phase place of individual element is in [0,2 π] or [π ,+π] value.For example, can get γ _Kj=(k+1) θ _j, k=0 wherein, 1 ..., N _T, θ _jBe a phase place value, can 0 between the pi/2 or-π/4 are to value between+π/4,

NB ₂It is positive integer greater than 1.Phase place is adjusted computing and can the channel status of the reflection of the code word in the first order code book further be quantized.Need to prove that phase place is adjusted matrix M atPhsAdj (j) and is not limited to the above-mentioned concrete form that provides, also can adopt other is the matrix of parameter with j.

To i, j, each value combination of δ=1 is adjusted computing according to the above-mentioned phase place of CW1 (i) enforcement of correspondence, can obtain a CMat _Ij ^δ=1, CMat _Ij ^δ=1Size is These CMat _Ij ^δ=1The code word that just can form δ=1 in the second level code book of this first order code book correspondence.

In the present embodiment, the base station can utilize second code word that obtains further to construct a matrix code word.At the transmitting antenna port number is N _T, during total number of plies v=2, the mode that this matrix code word is constructed in the base station is identical with embodiment one, repeats no more here.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration, have the system of more antennas, method by searching and calculate second code word and constructing the matrix code word that is suitable for the dual polarized antenna configuration with this code word in the time of can adopting above-mentioned 8 antennas equally as 16 antennas.

Embodiment five

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of 8 antennas that adopt the dual polarized antenna configuration, and as shown in Figure 5, this method comprises:

Step 51, subscriber equipment (UE) reports base station (being called eNB in LTE-A) with index information and total number of plies information v of a secondary code words, and this index information comprises the one-level index i and the secondary index j of this secondary code words, and i, j are the integer more than or equal to 0;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, and this secondary code words can be carried out extended arithmetic by this one-level code word and be obtained.

Step 52, the base station finds an one-level code word according to the i that receives and v from default first order code book, be designated as first code word, selects a kind of in following two kinds of compute modes to obtain a secondary code words according to the value of this i, is designated as second code word:

First kind, from a default known codebook, find one the 3rd code word according to j and v, one the 4th code word that obtains after compressing to the 3rd code word or to the 3rd code word with the spin matrix of this first code word correspondence is rotated, and obtains this second code word.

The specific algorithm of this compute mode describes in detail in embodiment three, no longer repeats here.At each i value of this compute mode correspondence, get different j values and do above-mentioned twiddle operation or compression and twiddle operation, just can obtain the part code word of δ=1 in the second level code book of this first order code book correspondence.Part code word wherein can be default.

Second kind is after a default phase place of parameter is adjusted matrix with j with the value substitution of j, this phase place is adjusted matrix and this first code word multiplies each other, and obtains this second code word.

The specific algorithm of this compute mode describes in detail in embodiment four, no longer repeats here.At each i value of this compute mode correspondence, get different j values and do above-mentioned twiddle operation or compression and twiddle operation, just can obtain another part code word of δ=1 in the second level code book of this first order code book correspondence.Part code word wherein can be default.The corresponding relation of i value and compute mode is got final product by UE and base station agreement.A kind of mode is that part code word that agreement is suitable for correlated channels is adjusted computing with phase place and expanded, and the code word that is suitable for non-correlation channel is expanded with rotation and compaction algorithms, and suitable and which kind of channel can be determined according to the result of emulation.

Provide one below and use example.

First order code book is the Rel-8 code book, and the code word in the code book of the second level is to obtain by the code word in the first order code book being carried out expand after the computing.Two kinds of multi-form expansions are used to improve the feedback accuracy of different types of channels.

Preceding 8 code words for the R8 code book are DFT code words, and they are suitable for correlated channels.So at i=0,1,2 ..., 7 o'clock, carry out following phase place and adjust computing:

$\mathrm{CW}2(i,j)=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \exp \left({(-1)}^{1/2}\frac{\mathrm{\&pi;}(2j-5)}{32}\right)& 0& 0\\ 0& 0& \exp \left({(-1)}^{1/2}\frac{2\mathrm{\&pi;}(2j-5)}{32}\right)& 0\\ 0& 0& 0& \exp \left({(-1)}^{1/2}\frac{3\mathrm{\&pi;}(2j-5)}{32}\right)\end{array}\right]\mathrm{CW}1\left(i\right)$

J=0 wherein, 1,2,3, i after each value computing of 0～7, has just been obtained the part code word of δ=1 in the code book of the second level based on preceding 8 code words expansion of Rel-8 code book δ=1.

For back 8 code words of Rel-8 code book δ=1, they are suitable for non-correlation channel.So at i=8,9 ...,, obtain second code word at 15 o'clock by following compression and twiddle operation:

$\mathrm{CW}2(i,j)=\mathrm{MatRot}\left(j\right)\left[\begin{array}{cccc}\sqrt{1-{\mathrm{\&alpha;}}^2(1-{\mathrm{\&beta;}}^2)}/\mathrm{\&beta;}& 0& 0& 0\\ 0& \mathrm{\&alpha;}& 0& 0\\ 0& 0& \mathrm{\&alpha;}& 0\\ 0& 0& 0& \mathrm{\&alpha;}\end{array}\right]\&CenterDot;\mathrm{CW}1\left(i\right)$

Wherein, j=0,1,2,3, for the UMi channel, α=0.5 is for 3GPP Case1 channel, α=0.2.I after each value computing of 8～15, has just been obtained the remainder code word of δ=1 in the code book of the second level based on back 8 code words expansion of Rel-8 code book δ=1.

In the present embodiment, the base station can utilize second code word that obtains further to construct a matrix code word.At the transmitting antenna port number is N _T, during total number of plies v=2, the mode that this matrix code word is constructed in the base station is identical with embodiment one, repeats no more here.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration, have the system of more antennas, method by searching and calculate second code word and constructing the matrix code word that is suitable for the dual polarized antenna configuration with this code word in the time of can adopting above-mentioned 8 antennas equally as 16 antennas.

Embodiment six

Present embodiment has proposed the method that a kind of base station obtains channel condition information at the system of 8 antennas that adopt the dual polarized antenna configuration, and as shown in Figure 6, this method comprises:

Step 61, UE reports the base station with index information and total number of plies information v of two secondary code words, and described index information comprises the one-level index i and the secondary index j of a secondary code words, and the index i and the j ' of another secondary code words;

Above-mentioned one-level index i also is the index of one-level code word in the first order code book simultaneously, these two secondary code words all are to carry out extended arithmetic by this one-level code word to obtain, certainly be that operation result is saved as secondary code words, UE does not need to carry out this computing, and other embodiment together.

Step 62, the base station finds an one-level code word according to i that receives and v from this default first order code book, be designated as first code word, obtain one second code word based on this first code word and j computing, obtain another second code word based on this first code word and j ' computing, two second code words are secondary code words.

The method among embodiment three or embodiment four or the embodiment five can be adopted in the base station, obtain one second code word based on this first code word and j computing, adopt identical method to obtain another second code word based on this first code word and j ' computing, just the value of j and j ' is different, the second code word difference that computing obtains.

In the present embodiment, the base station can utilize two second code words that obtain further to construct a matrix code word.At the transmitting antenna port number is N _T, during total number of plies v=2, the mode that this matrix code word is constructed in the base station is identical with embodiment two, repeats no more here.

Present embodiment also is applicable to and adopts the dual polarized antenna configuration, have the system of more antennas, method by searching and calculate second code word and constructing the matrix code word that is suitable for the dual polarized antenna configuration with this code word in the time of can adopting above-mentioned 8 antennas equally as 16 antennas.

Embodiment seven

For application scenarios of the present invention is described, the general processing procedure that once Single User MIMO and multiuser MIMO dynamically switch transmission mode is described below, as shown in Figure 1, comprising:

Step 1, eNB sends descending channel information pilot reference information to user terminal UE, is used for user terminal test down channel state;

Step 2, UE carries out down channel according to the pilot frequency information that receives and estimates;

Step 3, UE determines the form of feeding back channel state information, comprises index information and total number of plies information of code word;

UE can travel through secondary code words in the default code book (also can adopt the mode of computing to generate the code word of second level code book), compare with the descending channel information that measures, select near secondary code words, and the index of this secondary code words feeds back to eNB as PMI.Also can do this processing equally to the one-level code word.

The index information of secondary code words can comprise i, j, and i, the implication of j is with embodiment one or embodiment three (implication of j is with embodiment three among embodiment four or the embodiment five); Perhaps, the index information of this secondary code words can comprise i, j, and j ', i, j, the implication of j ' is with embodiment two or embodiment six.

Step 4, the channel condition information that UE will comprise index information and total number of plies information reports eNB, and channel condition information can also comprise CQI information etc.;

Step 5, eNB obtains the matrix code word of indication current channel condition according to the channel condition information that reports, and eNB dispatches UE with reference to the code word that obtains, and selects downlink transmission mode and UE to communicate.

The base station can adopt the method for embodiment one to six to determine above-mentioned matrix code word.

Downlink transmission mode comprises following a kind of: SU-MIMO transmission mode, MU-MIMO transmission mode and SU/MU dynamically switch transmission mode etc., adopting under the transmission means relevant with MU-MIMO, the channel condition information that obtains of the foregoing description can be adopted in the base station.

Adopt the method for the invention can be embodied as the MU-MIMO system channel condition information with enough accuracy is provided.

Need to prove that if do not conflict, each feature among the embodiment of the invention and the embodiment can mutually combine, all within protection scope of the present invention.In addition, can in computer system, carry out in the step shown in the flow chart of accompanying drawing such as a set of computer-executable instructions, and, though there is shown logical order in flow process, but in some cases, can carry out step shown or that describe with the order that is different from herein.

Claims (15)

1. method of obtaining channel condition information is applied to the base station and adopts dual polarized antenna configuration and transmitting antenna port number more than or equal to 8 system, comprising:

Subscriber equipment reports the base station with the total number of plies information of downlink transfer and the index information of one or two secondary code words;

After the index information and total number of plies information that described subscriber equipment sends received in described base station, according to the secondary code words of described index information and total number of plies information acquisition correspondence;

Described base station constructs the matrix code word that is used to indicate current channel condition according to described secondary code words.

2. method as claimed in claim 1 is characterized in that:

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station, described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct in the following manner and be used for this matrix code word, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& u(i,j)\\ -u(i,j)& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

3. method as claimed in claim 1 is characterized in that:

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station, described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct in the following manner and be used for this matrix code word, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& 0\\ 0& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

4. method as claimed in claim 1 is characterized in that:

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station, the base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word by following formula, be designated as C _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& u_2(i,j^{\&prime;})\\ -u_1(i,j)& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂Another secondary code words that (i, j ') expression obtains, i, j ' are this secondary code words u ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

5. method as claimed in claim 1 is characterized in that:

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station, the base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word by following formula, be designated as C _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& 0\\ 0& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂Another secondary code words that (i, j ') expression obtains, i, j ' are this secondary code words u ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

6. as the method for claim 1 or 2 or 4, it is characterized in that:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, and the described index information of reporting base station is the index of a secondary code words, comprises the one-level index i and the secondary index j of this secondary code words, i, j are the integer more than or equal to 0;

Described base station finds this secondary code words according to index i, j and δ from default second level code book, wherein, and δ=v/2.

7. as the method for claim 1 or 2 or 4, it is characterized in that:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of a secondary code words, the one-level index i and the secondary index j that comprise this secondary code words, this secondary code words is obtained by an one-level code word expansion, this index i still is the index of this one-level code word, and i, j are the integer more than or equal to 0;

Described base station is according to index i and δ, finds this one-level code word from default first order code book, and carry out extended arithmetic according to this one-level code word and index j then and obtain this secondary code words, wherein, δ=v/2.

8. as the method for claim 1 or 3 or 5, it is characterized in that:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', i, j and j ' are the integer more than or equal to 0;

Described base station finds this first secondary code words according to index i, j and δ from default second level code book, according to index i, j ' and δ, find this second secondary code words from this second level code book, wherein, and δ=v/2.

9. as the method for claim 1 or 3 or 5, it is characterized in that:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', these two secondary code words are obtained by same one-level code word expansion, and this index i still is the index of this one-level code word, i, j and j ' are the integer more than or equal to 0;

Described base station is according to index i and δ, from default first order code book, find this one-level code word, carry out extended arithmetic according to this one-level code word and index j then and obtain this first secondary code words, carry out extended arithmetic according to this one-level code word and index j ' and obtain this second secondary code words, wherein δ=v/2.

10. as the method for claim 1 or 3 or 5, it is characterized in that this method is used between base station and subscriber equipment adopting multi-user's multiple-input and multiple-output (MIMO) transmission mode, or Single User MIMO and multiuser MIMO dynamically switch transmission mode.

11. a communication system, comprise subscriber equipment and adopt the dual polarized antenna configuration and the transmitting antenna port number more than or equal to 8 base station, it is characterized in that:

Described subscriber equipment is used for the total number of plies information of downlink transfer and the index information of one or two secondary code words are reported the base station;

Described base station is used for after receiving the index information and total number of plies information that described subscriber equipment sends, according to the secondary code words of described index information and total number of plies information acquisition correspondence, and construct the matrix code word that is used to indicate current channel condition according to described secondary code words.

12. communication system as claimed in claim 11 is characterized in that:

Described subscriber equipment is that the index information with a total number of plies information and a secondary code words reports the base station;

Described base station according to described index information and total this secondary code words of number of plies information acquisition after, when total number of plies v=2, construct by following formula and to be used for this matrix code word, be designated as C _II(N _t, v, i, j):

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& u(i,j)\\ -u(i,j)& u(i,j)\end{array}\right]$

Perhaps

$C_{\mathrm{II}}(N_t,v,i,j)=\left[\begin{array}{cc}u(i,j)& 0\\ 0& u(i,j)\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; U (i, j) this secondary code words of expression acquisition, i, j is the integer more than or equal to 0, represents the index information of this secondary code words.

13. communication system as claimed in claim 11 is characterized in that:

Described subscriber equipment is that the index information with total number of plies information and two secondary code words reports the base station;

Described base station according to described index information and total these two secondary code words of number of plies information acquisition after, when total number of plies v=2, construct this matrix code word by following formula, be designated as C _II(N _t, v, i, j, j '):

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& u_2(i,j^{\&prime;})\\ -u_1(i,j)& u_2(i,j^{\&prime;})\end{array}\right]$

Perhaps

$C_{\mathrm{II}}(N_t,v,i,j,j^{\&prime;})=\left[\begin{array}{cc}{u}_1(i,j)& 0\\ 0& u_2(i,j^{\&prime;})\end{array}\right]$

Wherein, N _tFor more than or equal to 8 positive integer, the transmitting antenna port number of expression base station; u ₁(i, j are this secondary code words u for i, a j) secondary code words of expression acquisition ₁(i, index j); u ₂(i, j ' are this secondary code words u for i, j) another secondary code words of expression acquisition ₂The index of (i, j '), i, j.j ' are the integer more than or equal to 0.

14., it is characterized in that as claim 11 or 12 described communication systems:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, and the described index information of reporting base station is the index of a secondary code words, comprises the one-level index i and the secondary index j of this secondary code words, i, j are the integer more than or equal to 0; Described base station finds this secondary code words according to index i, j and δ from default second level code book, wherein, and δ=v/2; Perhaps

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of a secondary code words, the one-level index i and the secondary index j that comprise this secondary code words, this secondary code words is obtained by an one-level code word expansion, this index i still is the index of this one-level code word, and i, j are the integer more than or equal to 0; Described base station is according to index i and δ, finds this one-level code word from default first order code book, and carry out extended arithmetic according to this one-level code word and index j then and obtain this secondary code words, wherein, δ=v/2.

15., it is characterized in that as claim 11 or 13 described communication systems:

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', i, j and j ' are the integer more than or equal to 0; Described base station finds this first secondary code words according to index i, j and δ from default second level code book, according to index i, j ' and δ, find this second secondary code words from this second level code book, wherein, and δ=v/2; Perhaps

Total number of plies information of described user equipment to report base station is total number of plies v of down channel, v is a positive integer, the described index information of reporting base station is the index of two secondary code words, the one-level index i and the secondary index j that comprise first secondary code words, and the one-level index i of second secondary code words and secondary index j ', these two secondary code words are obtained by same one-level code word expansion, and this index i still is the index of this one-level code word, i, j and j ' are the integer more than or equal to 0; Described base station is according to index i and δ, from default first order code book, find this one-level code word, carry out extended arithmetic according to this one-level code word and index j then and obtain this first secondary code words, carry out extended arithmetic according to this one-level code word and index j ' and obtain this second secondary code words, wherein δ=v/2.

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