CN100426707C - Method for processing feedback signal in closed-loop transmitting diversity system and its device - Google Patents

Abstract

The present invention discloses a processing method and a device for feedback signals in a closed loop transmission diversity system. In each time slot, a mobile terminal channel estimation module estimates the wireless path channel response of two transmitting antennas of a base station; the power of the first antenna and the second antenna is respectively figured out and is compared to generate FBI bits which are transmitted to the base station through an uplink channel; at least one FBI bit received recently is stored to a delay wire; the FBI bits in the delay wire are restored into power ratios; the weight of the transmitting power of the first antenna and the second antenna is figured out according to the power ratios; the transmitting power of the two antennas are adjusted. The present invention can enhance quantification precision under the condition without increasing processing delay. Consequently, the performance of the self-adaptive time-space transmission diversity system is enhanced.

Description

The processing method of feedback signal and device thereof in a kind of transmit diversity device

Technical field

The present invention relates to the space-time emission diversity technology, refer to a kind of space-time emission diversity method and device thereof of adjusting signal transmission power with adaptive mode in real time especially.

Background technology

Based on code division multiple access (Code Division Multiple Access, CDMA) third generation (3G of mode, Third Generation) mobile communication system wideband CDMA (WCDMA, Wideband CDMA) in the standard, share same section frequency range owing to the different user of users different in the same sub-district and adjacent cell is interior at one time, therefore, there is interference each other in the user, these interference-limited power system capacity and rate of information throughout.In order to improve power system capacity, can adopt multiple deversity scheme, as technology such as rake, space diversity and antenna diversities.In the system that adopts diversity technique, the same information content has a plurality of multi-form separate copies, after these separate copies are received the machine reception, (MaximumLikelihood, ML) principle make full use of the redundancy properties of information according to maximum likelihood, certain in addition special processing, can significantly reduce the bit error rate of transmission information, and reduce the required energy of wireless data transmission, thereby reduce interfering with each other between the user.As seen, diversity technique can improve power system capacity effectively.

In existing CDMA standard, Closed-Loop Transmit Diversity method T x A A (Transmit AdaptiveArray) has two kinds of patterns (being called Mode 1 and Mode 2).Under these two kinds of patterns, (wherein a pair of two transmitting antenna phase differences of pattern carry out 1 bit quantization, obtain 1 FBI bit for Feedback Indication, the FBI) production method of bit different feedback signals; Second pattern carries out 3 bit quantizations to two transmitting antenna phase differences, simultaneously amplitude ratio is also carried out 1 bit quantization, obtains 4 FBI bits; Then this FBI bit is sent to the base station by up channel, by the base station current FBI bit is handled again.

Yet, in existing CDMA standard, each time slot (Slot in the up channel, 10 milliseconds of 1 frames, be divided into 15 time slots) can only transmit a FBI bit, this restriction has influenced the performance of existing Closed-Loop Transmit Diversity method T x A A greatly, especially is in the situation under the high-speed mobile.Though the only every time slot of pattern one produces 1 FBI bit, quantified precision is too low; Pattern two has four FBI, though quantified precision improve, must 4 time slots of cost, cause postponing excessive, have a strong impact on the diversity performance under multispectral the reining in of height.

Summary of the invention

For addressing the above problem, the object of the present invention is to provide (the FeedBack Indication of feedback signal in a kind of transmit diversity device, FBI) processing method, by adopting the Code And Decode method and apparatus of new FBI bit, can meet under the prerequisite of existing standard, improve self adaptation space-time emission diversity (Adaptive Space-Time Transmit Diversity, the ASTTD) performance of system.

Another object of the present invention is to propose a kind of device of realizing feedback signal processing method in the above-mentioned transmit diversity device.

For achieving the above object, technical scheme of the present invention is as follows:

(the FeedBack Indication of feedback signal in a kind of transmit diversity device, FBI) processing method, transmit diversity systems when this system is adaptive space (Adaptive Space-Time Transmit Diversity ASTTD), may further comprise the steps at least:

In each time slot,

A, portable terminal estimate each footpath radio channel response of two transmit antennas of base station;

B, calculate the power of first antenna and second antenna and being compared respectively, if the power of first antenna greater than the power of second antenna, then the FBI bit is 1, otherwise the FBI bit is 0;

C, FBI bit transfer to the base station by up channel, and what the base station will be received recently is no less than 1 FBI bit storage in delay line;

D, according to the mapping relations of predetermined FBI bit and power ratio, the FBI bit in the delay line is reverted to power ratio;

E, calculate the weight of first antenna and the second antenna transmitting power, and adjust the transmitting power of two antennas according to power ratio.

The weight of calculating two antenna transmitting powers described in the step e is to utilize following formula:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">w</figure-callout>}}_1=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+{\left(\frac{1}{R}\right)}^2}}\\ {\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">w</figure-callout>}}_2=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+R^2}}\end{array}\right.,$

Wherein, w ₁Be the weight of the first antenna transmitting power, w ₂Be the weight of the second antenna transmitting power, K is the footpath number of wireless channel transmission, h _1kBe each footpath radio channel response of first antenna, h _2kBe each footpath radio channel response of second antenna, R is a power ratio.

The power that calculates first antenna and second antenna described in the step b is to utilize following formula: $\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">P</figure-callout>}1=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2,$ $\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">P</figure-callout>}2=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2,$ P wherein ₁Be the power of first antenna, P ₂Be the power of second antenna.

Feedback signal (FeedBack Indication in a kind of realization transmit diversity device, the device of processing method FBI), (the Adaptive Space-Time TransmitDiversity of transmit diversity systems when being positioned at adaptive space, ASTTD) in, this device comprises at least: the channel estimation module that is positioned at portable terminal, encoder, be positioned at the delay line module of base station, the power ratio generator, weight calculator, described channel estimation module receives each footpath radio channel response of antenna for base station, and antenna power issued encoder, the FBI bit that encoder produces passes through up channel, store delay line module into, the power ratio generator obtains the FBI bit from delay line module, recover power ratio and issue weight calculator, weight calculator output antenna transmitting power weight.

Described delay line module comprises and is no less than 1 memory cell, is used to store the FBI bit of sending recently.

Adopt the present invention, owing to can obtain to be no less than 1 FBI bit in real time, therefore when not increasing processing delay, can improve quantified precision, thus the performance of transmit diversity systems when improving adaptive space.

Description of drawings

The composition structural representation of transmit diversity systems when Fig. 1 is adaptive space;

Fig. 2 is a FBI coder structure schematic diagram of the present invention;

Fig. 3 produces flow chart for FBI bit of the present invention;

Fig. 4 is a FBI decoding device structural representation of the present invention;

Fig. 5 is the mapping relations schematic diagram of FBI bit and power ratio;

Fig. 6 is the diversity performance contrast schematic diagram of the present invention and prior art.

Embodiment

Describe specific implementation of the present invention in detail below in conjunction with accompanying drawing.

The composition structural representation of transmit diversity systems when Fig. 1 is adaptive space, as shown in Figure 1, this system comprises Space Time Coding module 101, has the launching antenna array 106 of two antennas and the receiver that receiving terminal comprises the maximum likelihood receiver module, and transmitting terminal also comprises: feedback path 104, feedback signal processing module 102, optimal weights computing module 103 and transmit power allocations module 105.Wherein, feedback path 104 is used to export the information from the relevant current wireless characteristic of channel of receiver; Feedback signal processing module 102 is used for receiving the information from the relevant current wireless characteristic of channel of feedback path, and does mapping and handle; 103 bases of optimal weights computing module are come the relevant characteristics of radio channels information of self feed back receiver module 102, calculate the transmitting power weight of two-way transmission channel; Transmit power allocations module 105 is used for adjusting the transmission power level of different antennae according to the transmitting power weight that receives; 106 of launching antenna arrays will be sent through two stand-alone antennas through the output behind Space Time Coding module 101 codings according to the current transmit power value.

Fig. 2 has represented FBI bit production method shown in the present.The channel estimation module that at first is positioned at portable terminal estimates each footpath radio channel response (h of two transmit antennas ₁₁, h ₁₂... h _1K) and (h ₂₁, h ₂₂... h _2K), wherein K is the footpath number of wireless channel transmission; Then these estimated values are imported the FBI encoder, and in encoder, carry out coding method shown in Figure 3: the power that calculates first antenna at first respectively $\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">P</figure-callout>}1=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2$ And the power of second antenna $P$ $2=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2,$ If it is 1 that the power P 1 of first antenna greater than the power P 2 of second antenna, is exported the FBI bit so, otherwise output FBI bit is 0.The every time slot of this process carries out once.

The FBI bit is delivered to the base station after transmitting through up channel, is collected and is handled by the base station, determines the transmitting power weight of each antenna in view of the above.

Fig. 4 has represented FBI bit decode procedure of the present invention.After the base station receives the FBI bit, nearest some FBI bits are stored in the delay line module 201, wherein L represents the length of delay line; According to the up-to-date FBI bit of receiving in L position, recover power ratio R according to predetermined mapping relations by power ratio generator 202, Fig. 5 has provided L=1,2, the 3 o'clock FBI bits mapping relations to power ratio R respectively; And this power ratio R delivered in the weight calculator 203; After weight calculator 203 receives power ratio R, calculate the weight w of two transmission antennas transmit power according to following formula ₁And w ₂, and according to w ₁And w ₂Adjust two transmit antennas transmitting powers.

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">w</figure-callout>}}_1=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+{\left(\frac{1}{R}\right)}^2}}\\ {\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="C0310001800101.png,C0310001800103.png"\; state="\{\{state\}\}">w</figure-callout>}}_2=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+R^2}}\end{array}\right.$

Adopted the present invention, the performance of Closed-Loop Transmit Diversity was compared with former diversity system during adaptive space, was significantly improved.Fig. 6 provided after the machine simulation as calculated each emission diversity performance relatively, as can be seen, use ASTTD behind the present invention after 80 kilometers/hour of speed performance than all the emission diversity method in the existing WCDMA agreement, all to get well as STTD and TxAA pattern 1.

The above only is the preferable specific implementation of the present invention, is not to be used to limit protection scope of the present invention.

Claims (5)

1, the processing method of feedback signal FBI in a kind of transmit diversity device, transmit diversity systems ASTTD when this system is adaptive space is characterized in that described method may further comprise the steps at least:

In each time slot,

A, portable terminal estimate each footpath radio channel response of two transmit antennas of base station;

B, calculate the power of first antenna and second antenna and being compared respectively, if the power of first antenna greater than the power of second antenna, then the FBI bit is 1, otherwise the FBI bit is 0;

C, FBI bit transfer to the base station by up channel, and what the base station will be received recently is no less than 1 FBI bit storage in delay line;

D, according to the mapping relations of predetermined FBI bit and power ratio, the FBI bit in the delay line is reverted to power ratio;

E, calculate the weight of first antenna and the second antenna transmitting power, and adjust the transmitting power of two antennas according to power ratio.

2, the processing method of feedback signal in the transmit diversity device as claimed in claim 1 is characterized in that the weight of two antenna transmitting powers of calculating described in the step e is to utilize following formula:

$\left\{\begin{array}{c}{w}_1=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+{\left(\frac{1}{R}\right)}^2}}\\ w_2=\frac{1}{\sqrt{1+{(\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2/\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2)}^2}}=\frac{1}{\sqrt{1+R^2}}\end{array}\right.,$

Wherein, w ₁Be the weight of the first antenna transmitting power, w ₂Be the weight of the second antenna transmitting power, K is the footpath number of wireless channel transmission, h _1kBe each footpath radio channel response of first antenna, h _2kBe each footpath radio channel response of second antenna, R is a power ratio.

3, the processing method of feedback signal in the transmit diversity device as claimed in claim 1, the power that it is characterized in that calculating first antenna described in the step b and second antenna is to utilize following formula: $P1=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{1k}\right|}^2,$ $P2=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{\left|h_{2k}\right|}^2,$ P wherein ₁Be the power of first antenna, P ₂Be the power of second antenna, h _1kBe each footpath radio channel response of first antenna, h _2kIt is each footpath radio channel response of second antenna.

4, a kind of device of realizing the described feedback signal processing method of claim 1, transmit diversity systems ASTTD when being arranged in adaptive space, it is characterized in that comprising: the channel estimation module that is positioned at portable terminal, encoder, be positioned at the delay line module of base station, the power ratio generator, weight calculator, described channel estimation module receives each footpath radio channel response of antenna for base station, and antenna power issued encoder, the FBI bit that encoder produces passes through up channel, store delay line module into, the power ratio generator obtains the FBI bit from delay line module, recover power ratio and issue weight calculator, weight calculator output antenna transmitting power weight.

5, device as claimed in claim 4 is characterized in that: described delay line module comprises and is no less than 1 memory cell, is used to store the FBI bit of sending recently.

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