CN103401659B - Uniflow beam forming method based on codebook in TD-LTE (Time Division Long Term Evolution) system - Google Patents

Abstract

Codebook-based single stream beam form-endowing method in a kind of TD-LTE system, comprising: antenna calibration compensation is carried out to 8 antenna of TD-LTE system; First phase normalization is carried out to 8 antenna of system, by new channel estimation value Channel estimation correction value H (1) (kaRx, n) after calculating phase normalization; Judge the granularity of beam shape-endowing weight value,If weight granularity is m radio bearer block,If m amp; gt; 1, then first the channel estimation value of m radio bearer block is averaging,Then it is transferred to the 4th step,If m=1,Directly it is transferred to the 4th step; The search of wave beam forming code book weight is carried out,According to related weight searching algorithm,Wave beam forming code book weight is searched for by channel estimation value H (1) (kaRx, n),Wave beam forming code book serial number is obtained,Judge whether to traverse all radio bearer blocks,If so,Then this figuration terminates,If not,Then go to third step. This approach reduce the complexities of beamforming algorithm, reduce system cost of implementation.

Description

Single current beam form-endowing method based on code book in a kind of TD-LTE system

Technical field

The present invention relates to multi-antenna technology (MIMO) field is and in particular to a kind of TD-LTE in TD-LTE wireless communication system Single current beam form-endowing method based on code book in system.

Background technology

LTE is constantly subjected to the favor of Mobile Communication Industry.With the development of LTE technology, more and more world-leading fortune The evolution tendency that LTE is faced the future by battalion business one after another as network, equipment manufacturers also increase the throwing in LTE field one after another Enter, thus having promoted the continuous advance of LTE.Compared with G mobile communication, LTE has following technical characteristic：(1) Reduce every bit cost, improve uplink and downlink communication data rate；(2) spectrum efficiency improves, and flexibly uses existing and new frequency Section；(3) ensure service quality, the offer ability activated business, with lower cost, the more preferably more industry of Consumer's Experience offer Business；(4) reduce wireless network time delay, simplify framework, open interface；(5) increase cell edge bit rate, keep current base Increase cell edge bit rate etc. in the case that station location is constant.

MIMO technique refers to carry out the technology of space diversity using multi-emitting, many reception antennas.It adopts Being discrete multiple antennas, effectively communication link being resolved into many parallel subchannels, thus greatly improving capacity.? The downlink of TD-LTE, the sending method of multiple antennas mainly includes transmitting diversity, wave beam forming, space-time and coding and multi-user The technology 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 To ensure the technical scheme that performance can be selected in various environment to optimize.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, the strong correlation of utilization space channel and ripple Principle of interference have the radiation diagram of certain orientation, make the main lobe adaptive sensing user of antenna pattern, thus carrying High s/n ratio, obtains obvious array gain.The purpose of wave beam forming, is to expand signal cover, improving edge and gulp down The amount of telling and suppression interference.How effectively efficiently to produce the change that beam shape-endowing weight value carrys out match channels, thus improving system Handling capacity, becomes the sole criterion weighing beamforming algorithm.

The single current beamforming technique based on dedicated pilot is supported, according to agreement, in transmitting procedure, user in LTE R8 Terminal needs to estimate the equivalent channel after wave beam forming by the measurement to dedicated pilot, relevant detection of going forward side by side.In order to Experienced channel is transmitted, base station must send a wave beam forming with Simultaneous Transmission of Data with reference to letter after estimating wave beam forming Number, this reference signal is that user is special, and the transmission corresponding to user's DRS (Dedicated Reference Signal) is referred to as the biography using antenna port 5 Defeated.Beamforming technique can effectively improve the service quality of Cell Edge User, and forming vectors are become with the coupling of present channel For affecting the key factor of figuration effect, because wireless channel environment often changes rapidly, therefore realize system descending wave beam and assign Shape not only will consider figuration effect, and it is also contemplated that the processing speed of figuration.

TD-LTE system down beam shaping mainly adopts the method computation complexity based on singular value decomposition higher at present.

Content of the invention

The technical problem to be solved is to overcome the shortcoming of prior art, provides that a kind of method is simple, cost Single current beam form-endowing method based on code book in TD-LTE system that is low, being easy to software and hardware enforcement.

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

TD-LTE8 antenna beam figuration code book is：

Wherein, i=0,1 ..., 15；J=0,1 ..., 15, k=0,1 ..., 15, codebook selecting 16 × 16 × 16 altogether,

φ_k=e^jπk/16,

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

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

(1), antenna calibration compensation is carried out to TD-LTE system 8 antenna, according to original channel estimateWith Up correction weight computing goes out channel estimation after antenna calibration compensatesWherein n is that radio bearer block number mesh indexes, ka_RxFor antenna index, u is user terminal index；

(2), first phase normalization is carried out to system 8 antenna, by new channel estimation valueCalculate phase place normalizing Channel estimation correction value H after change₍₁₎(ka_Rx,n)；Seek the phase theta of every first antenna of radio bearer block,

Every radio bearer block is normalized according to antenna 1 phase place,

(3), judge the granularity of beam shape-endowing weight value, if weights granularity is m radio bearer block, if m>1, first right The channel estimation value of m radio bearer block is averaging, then proceeds to step (4)；If m is 1, proceed to step (4)；

(4), carry out the search of wave beam forming code book weights, according to related weights searching algorithm, by channel estimation value H₍₁₎ (ka_Rx, n) search for wave beam forming code book weights, obtain wave beam forming code book sequence number,

In order to simplify search space, in i, search in 16 × 16 × 16 code book that j, k collectively constitute, respectively wave beam forming Code book weights are searched for, and meet wave beam forming code book sequence number i of following formula, j, k, are calculated as follows：

G11 (i)=v_i ^T×H₍₁₎(index1,Loop)

Wherein, index1 is corresponding 4 antennas of port0, then computing as the following formula；

Search 16 times, obtains I₁；

G12 (j)=v_j ^T×H₍₁₎(index2,Loop)

Wherein, index2 is corresponding 4 antennas of port1, then computing as the following formula；

Search 16 times, obtains J₁；

Search 16 times, obtains K₁；

Obtain TD-LTE8 antenna beam figuration code book sequence number PMI_W1(I₁,J₁,K₁)；

Up to the complete all radio bearer blocks of searching loop, wave beam forming terminates；

Judge whether to travel through all radio bearer blocks, if it is, this figuration terminates, if it is not, then going to step (3).

The method that the present invention adopts precoding, presets wave beam forming code book in systems, is realized by searching for weighted vector Efficiently quick figuration.The present invention proposes a kind of beam form-endowing method based on codebook search, by building shape-endowing weight value code book, root According to channel-estimation information, code presupposition is scanned for, realize single current wave beam forming.After the present invention, the answering of single current wave beam forming Miscellaneous degree substantially reduces, and figuration effect is close to the related algorithm based on singular value decomposition.In beamforming process, need not count Calculate spatial correlation matrix, and calculating process, without singular value decomposition, greatly reduces the amount of calculation of single current wave beam forming, compared to Traditional singular value decomposition method is it is easier to software and hardware is realized.

Brief description

Fig. 1 is the wave beam forming overall process flow figure based on code book for the TD-LTE system.

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

Specific embodiment

The present invention is described in more detail with reference to the accompanying drawings and examples, but the invention is not restricted to these embodiments.

Embodiment 1

In the present embodiment TD-LTE system, the single current beam form-endowing method step based on code book is as follows：

Accompanying drawing 2 is seen with user terminal antenna setting in base station.

The first step：TD-LTE8 antenna is carried out with antenna calibration and compensates 11, according to original channel estimate With up correction weightsCalculate the channel estimation value after new antenna calibration compensatesCount as the following formula Calculate；

Wherein n is that radio bearer block number mesh indexes, ka_RxFor antenna index, u is user terminal index.

Note：Up correction weightsComputational methods as follows, on obtaining each passage, each subcarrier is average After H, also just obtain the magnitude-phase characteristics of each subcarrier, on the basis of certain passage, calculate each passage relatively with online bearing calibration In the sensor gain and phase uncertainties of reference channel, obtain the penalty coefficient of each antenna channels, that is, correct weights；

Second step：First phase normalization is carried out to system 8 antenna, by new channel estimation valueCalculate phase place to return Channel estimation correction value H after one change₍₁₎(ka_Rx, n), ka_RxFor antenna index, calculated as the following formula；

Loop=1:M, M are radio bearer block sum, in the present embodiment, take M to be 8.

1. seek the phase theta of every first antenna of radio bearer block

2. every radio bearer block is normalized according to antenna 1 phase place

Carry out 8 circulations.

3rd step：Judge the granularity 12 of shape-endowing weight value, if weights granularity is m radio bearer block, if m>1, then first The channel estimation value of m radio bearer block is averaging, then proceeds to the 4th step, m radio bearer block channel estimation value asks flat Equal 13, computing formula is summarized as follows；If m=1, directly proceed to the 4th step；

Loop=1:M, M are radio bearer block sum, in the present embodiment, take M to be 8.

4th step：Wave beam forming code book weights search 14, v_mFor code book 1 (m=0-15),For code book 2 (n=0-15)； Finally try to achieve corresponding wave beam forming code book sequence number 15PMI on radio bearer block₁(I, J, K), concrete calculating process is as follows.

(1) when weights granularity m is 1 radio bearer block Loop=1:M, M are radio bearer block sum, in the present embodiment, M is taken to be 8；

In order to simplify search space, search in i, 3 16 code books of j, k. wave beam forming code book weights search 17 respectively, Meet wave beam forming code book sequence number i of following formula, j, k, be calculated as follows：

G11 (i)=v_i ^T×H₍₁₎(index1,Loop)

Wherein, index1 is corresponding 4 antennas of port0, preserves, then computing as the following formula；

Search 16 times, obtains I₁；

G12 (j)=v_j ^T×H₍₁₎(index2,Loop)

Wherein, index2 is corresponding 4 antennas of port1, preserves, then computing as the following formula；

Search 16 times, obtains J₁；

Search 16 times, obtains K₁；

Obtain TD-LTE8 antenna beam figuration code book sequence number 18, PMI_W1(I₁,J₁,K₁)

Until the complete all radio bearer blocks 19 of searching loop, wave beam forming terminates 20.

(2) weights granularity m>1 radio bearer block

Loop=1：M is radio bearer block sum, M value 8 in the present embodiment, and m is shape-endowing weight value granularity, m Value is 2.

With m=1 radio bearer block, what the channel estimation using during search took is average to W1 search wave beam forming code book process Value

Carry out 4 circulations.Until the complete all radio bearer blocks 16 of searching loop, wave beam forming terminates 20.

Claims (1)

1. in a kind of TD-LTE system the single current beam form-endowing method based on code book it is characterised in that the method is by following steps group Become：

TD-LTE8 antenna beam figuration code book is：

Wherein, i=0,1 ..., 15；J=0,1 ..., 15, k=0,1 ..., 15, codebook selecting 16 × 16 × 16 altogether,

φ_k=e^jπk/16,

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

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

(1), antenna calibration compensation is carried out to TD-LTE system 8 antenna, according to original channel estimateWith up Correction weight computing goes out channel estimation after antenna calibration compensatesWherein n is that radio bearer block number mesh indexes, ka_Rx For antenna index, u is user terminal index；

(2), first phase normalization is carried out to system 8 antenna, by new channel estimation valueAfter calculating phase normalization Channel estimation correction value H₍₁₎(ka_Rx,n)；Seek the phase theta of every first antenna of radio bearer block,

$\mathrm{\θ}=arctan\left(\frac{imag\left(\stackrel{\‾}{H_1}\right(1,Loop\left)\right)}{real\left(\stackrel{\‾}{H_1}\right(1,Loop\left)\right)}\right)$

Every radio bearer block is normalized according to antenna 1 phase place,

$H_{\left(1\right)}({\mathrm{ka}}_{Rx},Loop)=\frac{\stackrel{\‾}{H_1}({\mathrm{ka}}_{Rx},Loop)}{\cos \mathrm{\θ}+j\sin \mathrm{\θ}};$

(3), judge the granularity of beam shape-endowing weight value, if weights granularity is m radio bearer block, if m>1, first to m The channel estimation value of radio bearer block is averaging, then proceeds to step (4)；If m is 1, proceed to step (4)；

(4), carry out the search of wave beam forming code book weights, according to related weights searching algorithm, by channel estimation value H₍₁₎(ka_Rx,n) Search wave beam forming code book weights, obtain wave beam forming code book sequence number,

In order to simplify search space, in i, search in 16 × 16 × 16 code book that j, k collectively constitute, respectively wave beam forming code book Weights are searched for, and meet wave beam forming code book sequence number i of following formula, j, k, are calculated as follows：

G11 (i)=v_i ^T×H₍₁₎(index1,Loop)

Wherein, index1 is corresponding 4 antennas of port0, then computing as the following formula；

$G{11}_{max}=\underset{i}{\arg }\left(max\right\{\left|G11\right(i\left){|}^2\right\})$

Search 16 times, obtains I₁；

G12 (j)=v_j ^T×H₍₁₎(index2,Loop)

Wherein, index2 is corresponding 4 antennas of port1, then computing as the following formula；

$G{12}_{max}=\underset{j}{\arg }\left(max\right\{\left|G12\right(j\left){|}^2\right\})$

Search 16 times, obtains J₁；

$G{1}_{max}=\underset{k}{\arg }\left(max\right\{\left|G1\right(k\left){|}^2\right\})$

Search 16 times, obtains K₁；

Obtain TD-LTE8 antenna beam figuration code book sequence number PMI_W1(I₁,J₁,K₁)；

Up to the complete all radio bearer blocks of searching loop, wave beam forming terminates；

Judge whether to travel through all radio bearer blocks, if it is, this figuration terminates, if it is not, then going to step (3).