CN103368628B - Double-current beam forming method based on code books in TD-LTE system - Google Patents

Abstract

Provided is a double-current beam forming method based on code books in a TD-LTE system. The double-current beam forming method includes the steps of selecting TD-LTE 8 antenna code books, carrying out antenna correction compensation, computing a channel estimated value H after the antenna correction compensation according to an original channel estimated value and an up-going correction weight, judging whether user terminal antennas are transmitted in turns, if yes, judging whether the H is successfully matched, if yes, combining a matrix [H1,H2] and estimating normalized initial phases of M RB channels according to antennas, and changing the combined matrix into [H(1), H(2)], judging granularity of a figurative weight, setting the weight granularity to be m RB, if m＞1, averaging channel estimated values of m RB and searching the double-current beam forming code book weight; if m=1, searching the double-current beam forming code book weight, traversing all RB and then finishing operation. According to the double-current beam forming method based on the code books in the TD-LTE system, the beam forming code book is preset on a base station side, two orthorhombic code book weights are searched according to user channel information, therefore, quick forming is achieved, and wireless performance of the TD-LTE system is improved.

Description

A kind of dual-stream beamforming method in TD-LTE system based on code book

Technical field

The invention belongs to antenna technical field, and in particular to the dual-stream beamforming side in TD-LTE system based on code book Method.

Background technology

2000, the leading TD-SCDMA mobile communication standards of China were formally received to 3G international standards by ITU and 3GPP One of, this is important breakthrough of the China in telecommunication technology history, is marked as the follow-up evolution scheme TD-LTE of TD-SCDMA standards Standard is also favored by Mobile Communication Industry, under the actively promoting of the Chinese government and relevant manufactures, the TD-LTE- that China submits to Advanced is evaluated to be formally classified as IMT-Advanced (4G) international standard.Compared with 3G technology, LTE system has following spy Levy：(1) traffic rate and spectrum efficiency are improve；(2 ensure service quality, the offer ability activated business, with it is lower into Originally, more preferably Consumer's Experience provides more business；(3) system bandwidth configuration is more flexible；(4) clearly propose that system is supporting high On the basis of speed is mobile, need to be thought of as low speed user offer optimal conditions, while improving the handling capacity of Cell Edge User.It is many Antenna technology can bring effective diversity gain and array gain as one of LTE system key technology to system.

MIMO technique refers to the technology that space diversity is carried out using multi-emitting, multiple receive antenna.What it was adopted It is discrete multiple antennas, effectively communication link can be resolved into into many parallel subchannels, so as to greatly improve capacity. The downlink of TD-LTE, the sending method of multiple antennas mainly includes transmitting diversity, wave beam forming, space-time with coding and multi-user The technologies such as multiple-input and multiple-output.TD-LTE system supports abundant application scenarios, which defines the transmission mode of 9 kinds of downlink business With the technical scheme for ensureing that performance can be selected to optimize in various environment.Wherein, emission mode 7, emission mode 8 and transmitting Pattern 9 is beam-forming mode.

Wave beam forming is a kind of Signal Pretreatment technology based on aerial array, and its operation principle is utilization space channel The principle of interference of strong correlation and ripple has the radiation diagram of certain orientation, makes the adaptive sensing of main lobe of antenna pattern User, so as to improve signal to noise ratio, obtains obvious array gain.The purpose of wave beam forming, be in order to expand signal cover, Improve edge throughput and suppress interference.How the change that beam shape-endowing weight value carrys out match channels is effectively efficiently produced, so as to The handling capacity of raising system, becomes the sole criterion for weighing beamforming algorithm.

Wave beam forming extend to stream transmission by LTE R9, so as to realize the knot of wave beam forming and space multiplexing technique Close.Dual-stream beamforming technology be applied to signal dispersion body relatively sufficiently under the conditions of, combine intelligent antenna technology and how defeated Enter multi-output space multiplexing, and traditional single current beamforming technique can be kept extensively to cover, cell capacity is big and disturbs little Characteristic, can both improve the reliability of edge customer, while the handling capacity of Cell Center User can be lifted effectively.It is fixed in LTE R9 Justice dual-port dedicated pilot newly, and introduce new control signaling, antenna configurations are 8 × 2.

Based on the method that current TD-LTE system down beam shaping mainly adopts singular value decomposition, computation complexity is higher.

The content of the invention

The technical problem to be solved is the shortcoming for overcoming prior art, there is provided a kind of method is simple, can Realize that dual-stream beamforming, the complexity of dual-stream beamforming be low, base in the TD-LTE system that the feedback of the information between subsystem is low In the dual-stream beamforming method of code book.

The technical scheme that solution above-mentioned technical problem is adopted is comprised the steps of：

On the basis of the single current wave beam forming based on code book, it is proposed that a kind of dual-stream beamforming side based on code book Method, the relatively conventional singular value decomposition method of the method, reduces the complexity of TD-LTE system dual-stream beamforming, TD- LTE8 antenna beam figuration codebook designs are as follows：

Wherein,

The natural number of k=0-15,

v_i=[1 e^j2π*2*i/32 e^j4π*2*i/32 e^j6π*2*i/32]^T

v_j=[1 e^j2π*2*j/32 e^j4π*2*j/32 e^j6π*2*j/32]^T

Wherein, i=0,1 ..., 15；J=0,1 ..., 15.

TD-LTE8 antenna beam figuration codebook selectings have 16 × 16 × 16 altogether.

1st, antenna calibration compensation is carried out to the antenna of TD-LTE system 8, according to original channel estimated valueWith it is upper Row correction weight computing goes out channel estimation after antenna calibration compensationWherein n is RB numbers index, ka_RxFor antenna Index, u is user index, and i is user u transmitting antennas index, and i values are 1 or 2；RB is Resource Block；

2nd, judge whether user terminal antenna takes turns to send out, if user terminal antenna wheel is sent out, step 3 is proceeded to, if do not taken turns Send out, then proceed to the double-current weights state of single current weights construction.

3rd, the whether successful matching of subscriber channel matrix H is judged, H is 8 × 1 channel matrix, if successful matching, proceeds to Step 4, if pairing is unsuccessful, proceeds to the double-current weights state of single current weights construction.

4th, combinatorial matrix [H₁,H₂], and by antenna respectively to the channel estimation value normalization first phase of M RB, combinatorial matrix becomes Into [H₍₁₎,H₍₂₎]；

5th, the granularity of shape-endowing weight value is judged, if weights granularity is m RB, if m>1, then first to the channel of m RB Estimated value is averaging, and then searches for dual-stream beamforming code book weights；If m is 1, dual-stream beamforming code book is directly searched Weights.

6th, travel through after all RB and terminate.

The beneficial effect that the present invention is brought:The simple dual-stream beamforming for efficiently realizing TD-LTE system, reduces TD- Feedback of the information between LTE subsystems, reduces system implementation complexity.

Description of the drawings

Fig. 1 is dual-stream beamforming overall process flow figure of the TD-LTE system based on code book.

Fig. 2 is base station and user terminal antenna set-up mode figure.

Specific embodiment

With reference to the accompanying drawings and examples to this further description, but the invention is not restricted to these embodiments.

Embodiment 1

Dual-stream beamforming method and step in the TD-LTE system of the present embodiment based on code book is as follows：

Base station and user terminal antenna set-up mode such as Fig. 2.

The present embodiment processes RB number M, and value is 8.

The design of TD-LTE8 antenna codebooks wave beam forming is as follows：

The natural number of k=0-15,

v_i=[1 e^j2π*2*i/32 e^j4π*2*i/32 e^j6π*2*i/32]^T

v_j=[1 e^j2π*2*j/32 e^j4π*2*j/32 e^j6π*2*j/32]^T

Wherein, i=0,1 ..., 15；J=0,1 ..., 15；

Codebook selecting has 16 × 16 × 16 altogether.

The first step：Start 11, antenna calibration compensation 12 carries out antenna calibration compensation, according to original to the antenna of TD-LTE system 8 Beginning channel estimation valueGo out channel estimation after antenna calibration compensation with up correction weight computing

Wherein, wherein n is that RB numbers index ka_RxFor antenna index, u is user index, and i is user u transmitting antennas index, I values are 1 or 2；RB is Resource Block；(present invention adopts the processing mode consistent with user terminal antenna side single-antenna transmission)

Note：Up correction weightsComputational methods it is as follows, the average H of each subcarrier on each passage is obtained Afterwards, also just obtained the magnitude-phase characteristics of each subcarrier, on the basis of certain passage, have on-line correction method calculate each passage relative to The sensor gain and phase uncertainties of reference channel, just obtain the penalty coefficient of each antenna channels, that is, correct weights；

Second step：Judge whether user terminal antenna takes turns and send out 13, if user terminal antenna wheel is sent out, proceed to the 3rd step, If do not take turns sent out, the double-current weights state 14 of single current weights construction is proceeded to；

3rd step：Judge H whether successful matchings 15, if successful matching, proceed to the 4th step, if pairing is unsuccessful, Then proceed to the double-current weights state 16 of single current weights construction；The double-current weights method of single current weights construction is as follows；

If weights granularity m=1RB or weights granularity m>1RB

1. with the acquisition of single current weights searching method, PMI₁(I₁,J₁,K₁)；

2. the default code book of query search, finds and PMI₁(I₁,J₁,K₁) orthogonal element, constitute code book collection Q, it is assumed that this code Originally it is concentrated with L element；

3. L code book is circulated traversal search L time in couple code book collection Q, and searching meets the i of following formula, and j, k. is denoted as PMI₂ (I₂,J₂,K₂)

Wherein, when m is 1, Loop=1 is circulated：M, works as m>When 1, Loop=1 is circulated：[M/m], in the present embodiment, M Value takes 8, also can use other positive integers；

4th step：Combinatorial matrix [H1, H2] 17, and the channel estimation value of M RB is normalized respectively just by antenna Phase, combinatorial matrix becomes [H₍₁₎,H₍₂₎] 18, concrete grammar is as follows：

1. the phase theta of each first antenna of RB is sought

2. it is normalized according to the phase place of antenna 1 per RB

Wherein, Loop=1 is circulated：M；

5th step：The granularity 19 of shape-endowing weight value is judged, if weights granularity is m RB, if m>1, then first to m RB Channel estimation value be averaging (step 20), then search for dual-stream beamforming code book weights 21；If m is 1, directly search Dual-stream beamforming code book weights 24, concrete grammar is as follows；

When weights granularity m is 1 RB

1. in order to simplify search space, scan in i, 3 groups of 16 code books of j, k, search respectively meets following formula PMI sequence numbers i, j, k is denoted as PMI₁(I₁,J₁,K₁)25

Search 16 times, obtains I₁, wherein, index1 is corresponding 4 antennas of port0；

Search 16 times, obtains J₁；

Search 16 times, obtains K₁；

Wherein, index2 is corresponding 4 antennas of port1, so far, PMI₁(I₁,J₁,K₁) search；

2. the default code book of query search, finds and PMI₁(I₁,J₁,K₁) orthogonal element, constitute code book collection Q, it is assumed that code book There is L element in collection Q；

3. L code book is circulated in couple code book collection Q, traversal search L time, and searching meets PMI sequence numbers i of following formula, j, k note It is PMI₂(I₂,J₂,K₂)

When weights granularity m>During 1RB

1. channel estimation H of couple m RB_(i)Value is averaging, and calculating formula is as follows

Wherein, jj=1,2 ..., Ka_Tx, Ka_TxFor Base Transmitter antenna index, i is user's transmitting antenna index, i take 1 or 2, circulate Loop=1：[M/m]；

2., in order to simplify search space, to search in i, 3 groups of 16 code books of j, k. search respectively meets the PMI sequences of following formula Number i, j, k 22

Search 16 times, obtains I₁, in, index1 is corresponding 4 antennas of port0；

Search 16 times, obtains J₁, in, index2 is corresponding 4 antennas of port1；

Search 16 times, obtains K₁；

Wherein, circulation circulation Loop=1：[M/m]

3. the default code book of query search, finds and PMI₁(I₁,J₁,K₁) orthogonal element, constitute code book collection Q, it is assumed that code book There is L element in collection Q；

4. L code book is circulated in couple code book collection Q, traversal search L time, and searching meets i, j, the k of following formula, is denoted as PMI₂ (I₂,J₂,K₂)

Wherein, Loop=1 is circulated：[M/m]

6th step：Judge whether to have traveled through all RB23,26, finally terminate 27.

Claims (1)

1. the dual-stream beamforming method of code book is based in a kind of TD-LTE system, it is characterised in that comprised the steps of：

Select TD-LTE8 antenna beam figuration code books：

The natural number of k=0-15,

v_i=[1 e^j2π*2*i/32 e^j4π*2*i/32 e^j6π*2*i/32]^T

v_j=[1 e^j2π*2*j/32 e^j4π*2*j/32 e^j6π*2*j/32]^T

Wherein, i=0,1 ..., 15；J=0,1 ..., 15；

TD-LTE8 antenna beam figuration codebook selectings have 16 × 16 × 16 altogether；

(1) antenna calibration compensation is carried out to the antenna of TD-LTE system 8, according to original channel estimated valueWith up school Positive weight computing goes out channel estimation after antenna calibration compensationWherein n is RB numbers index, ka_RxFor day clue Draw, u is user index, i is user u transmitting antennas index, and i values are 1 or 2；RB is Resource Block；

(2) judge whether user terminal antenna takes turns to send out, if user terminal antenna wheel is sent out, step (3) is proceeded to, if do not taken turns Send out, then proceed to the double-current weights state of single current weights construction；

(3) the whether successful matching of subscriber channel matrix H is judged, H is 8 × 1 channel matrix, if successful matching, proceeds to step Suddenly (4), if pairing is unsuccessful, the double-current weights state of single current weights construction is proceeded to；

(4) combinatorial matrix [H₁,H₂], and by antenna respectively to the channel estimation value normalization first phase of M RB, combinatorial matrix becomes [H₍₁₎,H₍₂₎]；

Concrete grammar is as follows：

A. the phase theta of each first antenna of RB is sought

$\mathrm{\θ}=arctan\left(\frac{imag\left(\stackrel{\‾}{H_i}\right(1,Loop))}{real\left(\stackrel{\‾}{H_i}\right(1,Loop))}\right)$

B. it is normalized according to the phase place of antenna 1 per RB

$H_{\left(i\right)}({\mathrm{ka}}_{Rx},Loop)=\frac{\stackrel{\‾}{H_i}({\mathrm{ka}}_{Rx},Loop)}{\cos \mathrm{\θ}+j\sin \mathrm{\θ}}$

Wherein, Loop=1 is circulated：M；

(5) granularity of shape-endowing weight value is judged, if weights granularity is m RB, if m>1, then first to the channel estimation of m RB Value is averaging, and then searches for dual-stream beamforming code book weights；If m is 1, direct search dual-stream beamforming code book power Value；

1. when weights granularity m is 1 RB：

A. in order to simplify search space, scan in i, 3 groups of 16 code books of j, k, search respectively meets the PMI sequences of following formula Number i, j, k are denoted as PMI₁(I₁,J₁,K₁)

$G11\left(i\right)=\underset{i}{\arg }\left(max\right\{\[|{v_i}^T\×H_{\left(1\right)}(index1,Loop){|}^2+|{v_i}^T\×H_{\left(2\right)}\left(index1,Loop\right){|}^2\]\left\}\right)$

Search 16 times, obtains I₁, wherein, index1 is corresponding 4 antennas of port0；

$G12\left(j\right)=\underset{j}{\arg }\left(max\right\{\[|{v_j}^T\×H_{\left(1\right)}(index2,Loop){|}^2+|{v_j}^T\×H_{\left(2\right)}\left(index2,Loop\right){|}^2\]\left\}\right)$

Search 16 times, obtains J₁；

$G1\left(k\right)=\underset{k}{\arg }\left(\max \right\{\[|{\left[\begin{array}{c}{v}_I\\ v_J{\mathrm{\φ}}_k\end{array}\right]}^T\×H_{\left(1\right)}(\[index1;index2\],Loop){|}^2+|{\left[\begin{array}{c}{v}_I\\ v_J{\mathrm{\φ}}_k\end{array}\right]}^T\×H_{\left(2\right)}(\[index1;index2\],Loop){|}^2\]\})$

Search 16 times, obtains K₁；

Wherein, index2 is corresponding 4 antennas of port1, so far, PMI₁(I₁,J₁,K₁) search；

B. the default code book of query search, finds and PMI₁(I₁,J₁,K₁) orthogonal element, constitute code book collection Q, it is assumed that in code book collection Q There is L element；

C. L code book in code book collection Q is circulated, traversal search L time, searching meets PMI sequence numbers i of following formula, j, k is denoted as PMI₂(I₂,J₂,K₂)

$G2=\underset{i,j,k}{\arg }\left(\max \right\{\[|{\left[\begin{array}{c}{v}_i\\ v_j{\mathrm{\φ}}_k\end{array}\right]}^T\×H_{\left(1\right)}(\[index1;index2\],Loop){|}^2+|{\left[\begin{array}{c}{v}_i\\ v_j{\mathrm{\φ}}_k\end{array}\right]}^T\×H_{\left(2\right)}\left(\[index1;index2\],Loop\right){|}^2\]\left\}\right)$

2. when weights granularity m>During 1RB

A. to channel estimation H of m RB_(i)Value is averaging, and calculating formula is as follows

${\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(i\right)}(jj,Loop)=\frac{\underset{ii=1}{\overset{m}{\Σ}}{H}_{\left(i\right)}(jj,ii)}{m}$

Wherein, jj=1,2 ..., Ka_Tx, Ka_TxFor Base Transmitter antenna index, i is that user's transmitting antenna is indexed, and i takes 1 or 2, follows Ring Loop=1：[M/m]；

B. in order to simplify search space, search in i, 3 groups of 16 code books of j, k, search respectively meets PMI sequence numbers i of following formula, j,k；

$G11\left(i\right)=\underset{i}{\arg }\left(max\right\{\[|v_i^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(1\right)}(index1,Loop){|}^2+|v_i^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(2\right)}\left(index1,Loop\right){|}^2\]\left\}\right)$

Search 16 times, obtains I₁, in, index1 is corresponding 4 antennas of port0；

$G12\left(j\right)=\underset{j}{\arg }\left(max\right\{\[|v_j^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(1\right)}(index2,Loop){|}^2+|v_j^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(2\right)}\left(index2,Loop\right){|}^2\]\left\}\right)$

Search 16 times, obtains J₁, in, index2 is corresponding 4 antennas of port1；

$G1\left(k\right)=\underset{k}{\arg }\left(\max \right\{\[|{\left[\begin{array}{c}{v}_I\\ v_J{\mathrm{\φ}}_k\end{array}\right]}^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(1\right)}(\[index1;index2\],Loop){|}^2+|{\left[\begin{array}{c}{v}_I\\ v_J{\mathrm{\φ}}_k\end{array}\right]}^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(2\right)}(\[index1;index2\],Loop){|}^2\]\})$

Search 16 times, obtains K₁；

Wherein, Loop=1 is circulated：[M/m]

C. the default code book of query search, finds and PMI₁(I₁,J₁,K₁) orthogonal element, constitute code book collection Q, it is assumed that in code book collection Q There is L element；

D. L code book in code book collection Q is circulated, traversal search L time, searching meets i, j, the k of following formula, is denoted as PMI₂(I₂, J₂,K₂)

$G2=\underset{i,j,k}{\arg }\left(\max \right\{\[|{\left[\begin{array}{c}{v}_i\\ v_j{\mathrm{\φ}}_k\end{array}\right]}^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(1\right)}(\[index1;index2\],Loop){|}^2+|{\left[\begin{array}{c}{v}_i\\ v_j{\mathrm{\φ}}_k\end{array}\right]}^T\×{\stackrel{\‾}{\stackrel{\‾}{H}}}_{\left(2\right)}\left(\[index1;index2\],Loop\right){|}^2\]\left\}\right)$

Wherein, Loop=1 is circulated：[M/m]；

(6) travel through after all RB and terminate.