CN100421523C - Method for establishing reverse complemental channel branch - Google Patents

Abstract

The present invention discloses a method for establishing a branch of a reverse supplemental channel RSCH, which comprises the steps: a. a parameter is obtained by the measurement of more than one BTS, and reflects the channel quality from a wireless terminal to a BTS branch activated and concentrated by a fundamental channel FCH, and the parameter is sent to a base station controller BSC; B. the BSC sorts from the wireless terminal to the BTS branch activated and concentrated by the FCH in a descending order according to the size of the received parameter, and one or more than one branch is selected from the sort from the wireless terminal to the BTS branch activated and concentrated by the FCH in the highest order and serves as the RSCH branch established by the wireless terminal. The method ensures the channel quality of the RSCH branch established by the wireless terminal in a soft switchover region.

Description

A kind of method of setting up reverse complemental channel branch

Technical field

The present invention relates in wireless communication system, set up the technology of reverse complemental channel (RSCH), particularly a kind of method of setting up RSCH branch at soft handover area.

Background technology

In wireless communication system, in code division multiple access (CDMA), the reverse data of data service transmits on RSCH.When wireless terminal during at soft handover area, because wireless environment variation is violent, so need set up one or more RSCH branch according to wireless environment, distribute to wireless terminal transmission reverse data, the RSCH branch that is set up must be able to overcome the influence of the wireless environment variation of soft handover area to the wireless terminal calling, and wireless terminal can obtain soft handover gain simultaneously.Existing protocol regulation RSCH branch will be attached in primary channel (FCH) branch, so in Zone switched, the set that RSCH branch forms is the subclass of the set of FCH branch composition.Here, will be in Zone switched, the set that the RSCH branch that sets up for wireless terminal forms is called the RSCH Active Set, and the set that the FCH branch that sets up for wireless terminal forms is called the FCH Active Set.

For single wireless terminal, the number of the RSCH branch that sets up in soft handover area is The more the better, but for entire wireless communication system, the number of the RSCH branch that sets up for wireless terminal in soft handover area is many more, the resource of the wireless communication system that consumes is also just many more, and resource utilization will reduce.Therefore, must be according to the needs of single wireless terminal, in soft handover area, set up the RSCH Active Set of RSCH branch, make between the resource utilization of the soft handover gain of single wireless terminal and wireless communication system, to average out with suitable number for single wireless terminal.

If do not set up suitable R SCH branch for wireless terminal at soft handover area, the channel performance of RSCH will be unreliable, and the error rate of the reverse data that is transmitted just can not be protected, and the throughput of reverse data also can be affected.

If do not set up suitable R SCH branch for wireless terminal at soft handover area, the forward data that corresponding FCH branch is transmitted also can be affected.If the bad channel quality of the RSCH branch that set up, and the channel quality of corresponding FCH branch is good, can influence based on the host-host protocol of replying, as the transmission of the forward data of transmission control protocol (TCP).Response based on the forward data of the host-host protocol of replying is carried in the response packet, and the wireless communication system network side just can send new forward data after having only the RSCH branch that passes through to be set up to receive response packet.Therefore, the transmission rate of the forward data that FCH branch will transmit will reach maximization, and the response packet of the forward data correspondence that corresponding RSCH branch is transmitted just can not abandon or postpone.If the response packet of the forward data correspondence that corresponding RSCH branch is transmitted abandons or postpones, the transmission rate of the forward data that FCH branch will transmit will and then reduce, particularly it is serious when data are transmitted simultaneously with corresponding RSCH branch in FCH branch, this is that they are the inverse bandwidth of contention RSCH branch mutually because the response packet of reverse data and forward data correspondence all needs the transmission by RSCH branch.

For the wireless terminal in soft handover area is set up the bad RSCH branch of channel quality, the reverse data that is transmitted can go out the situation of active or delay, mainly be because: wireless terminal with " or " logic merge the reverse power control of each FCH branch, as long as there is a FCH branch to require wireless terminal to reduce transmitting power, then wireless terminal will reduce transmitting power.That is to say that oppositely the power control principle makes wireless terminal in order to save power, only safeguards the channel quality of a FCH branch.Simultaneously, the power of RSCH branch has a fixed bias with FCH branch again, and the power of each RSCH branch is with rising with falling.If it is relatively poor to set up the channel quality of RSCH branch, oppositely power control just can not be safeguarded the channel quality at RSCH branch place, FCH in bad channel quality branch and RSCH just do not have enough power, and the quality of the reverse data that transmits in this RSCH branch just can not get guaranteeing.

In the good branch of channel quality of the soft handover area of wireless terminal, set up RSCH and can guarantee the reverse data transmission of two-forty, many business in the wireless communication system, all need the reverse data transmission of two-forty as file loading and video telephone etc., the foundation of RSCH branch is necessary reliably, insecure RSCH branch will cause losing of reverse data or postpone, and influence the transmission rate of reverse data.

At present, the wireless terminal in the soft handover area is set up the forward pilot intensity that the RSCH ramifying depends on FCH branch in the FCH Active Set.When the wireless terminal in soft handover area will transmit reverse data, when the wireless communication system network side is set up RSCH branch for this wireless terminal, forward pilot intensity according to each branch in the measured FCH Active Set, after from high to low the branch in the FCH Active Set being sorted, in the FCH Active Set, select to be arranged in branch of one or several branches in prostatitis, distribute to this wireless terminal transmission reverse data as the RSCH Active Set of being set up.

Fig. 1 sets up the schematic diagram of RSCH branch for the wireless terminal of prior art in soft handover area.As shown in the figure: two branches are arranged in the FCH Active Set, be wireless terminal to the branch of base station transceiver (BTS) 1 with to the branch of BTS2, wherein, wireless terminal is strong to the forward pilot intensity of the FCH branch of BST2 to the forward pilot strength ratio wireless terminal of the FCH branch of BST1.If when setting up a RSCH branch for this wireless terminal, then select wireless terminal to the FCH branch of BST1 as the RSCH branch that sets up for this wireless terminal, this wireless terminal transmits reverse data by this RSCH branch.

Wireless terminal in soft handover area is set up the forward pilot intensity why the RSCH ramifying depends on each branch in the FCH Active Set, be based on following hypothesis: the environment of preceding reverse wireless communication system is similar with channel parameter, and the pairing reverse channel quality of the measured branch of Forward Pilot Channel matter also should be got well.Yet in the middle of reality, since the frequency difference of preceding backward channel, the modulator approach difference, and the interference that preceding backward channel is subjected to is also different with channel fading.In addition, the wireless communication system load of preceding backward channel also may be different.The asymmetry of backward channel that is to say that forward pilot intensity can not reflect pairing reverse channel quality before these situations all may cause.

Fig. 2 is the relativity figure of the backward channel intensity and the corresponding forward pilot intensity of two FCH branches in the prior art.As can be seen from the figure, the forward pilot intensity of the FCH branch 1 forward pilot intensity than FCH branch 2 always is strong, but the backward channel intensity of FCH branch 1 but often fluctuates under the backward channel intensity of FCH branch 2.The backward channel intensity that is to say the forward pilot intensity of FCH branch and this FCH branch that gets along well is directly proportional.

Is that wireless terminal is set up RSCH branch according to forward pilot intensity at soft handover area, can not guarantee the channel quality of the RSCH branch that set up, the RSCH branch that is set up there is a strong possibility can be of low quality, the error rate is high and transmission performance is low.When RSCH supported soft handover, the RSCH branch of the bad channel quality of being set up joined the RSCH Active Set, and this wireless terminal not only can not obtain soft handover gain, also wastes system resource; When RSCH did not support soft handover, when only allowing a RSCH branch, the RSCH of the bad channel quality of being set up can make the transmission of the reverse data of this wireless terminal be affected.

Therefore, how to guarantee to become a problem demanding prompt solution for the channel quality of the RSCH branch that sets up at the wireless terminal of soft handover area.

Summary of the invention

In view of this, main purpose of the present invention is to provide the method for a kind of RSCH of foundation, and this method can guarantee the channel quality into the RSCH branch that sets up at the wireless terminal of soft handover area.

According to above-mentioned purpose, technical scheme of the present invention is achieved in that

A kind of method of setting up reverse complemental channel RSCH branch, this method comprises:

A, more than one base station transceiver BTS send to base station controller BSC, the channel quality from wireless terminal to BTS branch in the intensity level reflection primary channel FCH Active Set that described reverse pilot intensity, reference pilot or reverse pilot intensity and forward pilot intensity combine with the intensity level that the reverse pilot intensity, reference pilot or the reverse pilot intensity that measure and forward pilot intensity combine;

The size of the intensity level that reverse pilot intensity, reference pilot or reverse pilot intensity that B, BSC basis is received and forward pilot intensity combine is to sorting from high to low to BTS branch from wireless terminal in the FCH Active Set, select in the highest one or more FCH Active Set of ordering from wireless terminal to BTS branch, as RSCH branch for this wireless terminal foundation.

Described measure when the reverse pilot intensity, the reverse pilot intensity process from wireless terminal to BTS branch in the described FCH of the measuring Active Set of steps A is:

Measure making an uproar than EcIo to the reverse pilot of BTS branch in the FCH Active Set, according to formula from wireless terminal $\mathrm{out}\left(n\right)=\left(\frac{W-1}{W}\right)\·\mathrm{out}(n-1)+\left(\frac{1}{W}\right)\·\mathrm{in}\left(n\right)$ After carrying out filtering, obtain the reverse pilot intensity in the FCH Active Set from wireless terminal to BTS branch;

Wherein, the filtered average reverse pilot EcIo of the moment n in out (n) the expression FCH Active Set from wireless terminal to BTS branch; The instantaneous reverse pilot EcIo of moment n in (n) the expression FCH Active Set from wireless terminal to BTS branch; W represents filtering parameter.

During the described intensity level that combines for reverse pilot intensity and forward pilot intensity that measures, the intensity level process that reverse pilot intensity from wireless terminal to BTS branch in the described FCH of the measuring Active Set of steps A and forward pilot intensity combine is: measure reverse pilot intensity and forward pilot intensity from wireless terminal to BTS branch the FCH Active Set respectively, obtain the intensity level that reverse pilot intensity and forward pilot intensity combine according to formula reverse pilot intensity+A * forward pilot intensity, wherein A is the weighted factor of forward pilot intensity, and A is less than 1.In the highest one or more FCH Active Set of the described selection of step B ordering from wireless terminal to BTS branch, as the RSCH ramifying of setting up for this wireless terminal be: B1, select in the FCH Active Set of ordering first from wireless terminal to BTS branch, as being first branch in the RSCH Active Set of this wireless terminal foundation; B2, for the residue in the FCH Active Set from wireless terminal to BTS branch, according to ordering judge successively reverse pilot intensity, reference pilot or the reverse pilot intensity of described branch and intensity level that forward pilot intensity combines whether respectively with the RSCH Active Set in reverse pilot intensity, reference pilot or the reverse pilot intensity of first branch and the difference of the intensity level that forward pilot intensity combines less than the RSCH soft handover biasing that is provided with, if, then described branch is joined in the RSCH Active Set of setting up into this wireless terminal, change step B3 over to; Otherwise, abandon described branch, process ends; B3, BSC are judged as the RSCH Active Set maximum branch number whether number of branches in the RSCH Active Set that this wireless terminal sets up reaches setting, if, process ends then; Otherwise, change step B2 over to, continue to select residue in the FCH Active Set from wireless terminal to BTS branch.

Described measure when the reverse pilot intensity, the RSCH soft handover of described setting is biased to the biasing of RSCH soft handover pilot frequency intensity.The intensity level that the described reverse pilot intensity of steps A, reference pilot or reverse pilot intensity and forward pilot intensity combine is the interface Abis link by BSC and BTS, sends to BSC's with the speed of 20 milliseconds of every frames.

The described more than one BTS administration of steps A covers the soft handover area at wireless terminal place.

From such scheme as can be seen, the present invention is when setting up RSCH branch for current wireless terminal in soft handover area, can be not be foundation with the forward pilot intensity of branch in the FCH Active Set of prior art, but be foundation with the parameter that can truly reflect the channel quality in the FCH Active Set from wireless terminal to BTS branch, as reverse pilot intensity, the intensity level that reference pilot or reverse pilot intensity and forward pilot intensity combine, select in the good FCH Active Set of reverse channel quality from wireless terminal to BTS branch as RSCH branch for wireless terminal foundation, thereby set up the good RSCH branch of channel quality for this wireless terminal.Therefore, method provided by the invention has guaranteed the channel quality for the RSCH branch that sets up at the wireless terminal of soft handover area.

Description of drawings

Fig. 1 sets up the schematic diagram of RSCH branch for the wireless terminal of prior art in soft handover area.

Fig. 2 is the relativity figure of the backward channel intensity and the corresponding forward pilot intensity of two FCH branches in the prior art.

Fig. 3 sets up the method flow diagram of RSCH branch for the wireless terminal of the present invention in soft handover area.

Fig. 4 sets up the method embodiment flow chart of RSCH branch for the wireless terminal of the present invention in soft handover area.

Embodiment

In order to make the purpose, technical solutions and advantages of the present invention clearer, below lift specific embodiment and, the present invention is described in more detail with reference to accompanying drawing.

The present invention is in order to set up the good RSCH branch of channel quality for the wireless terminal in soft handover area, the parameter that can truly reflect the channel quality from wireless terminal to BTS branch in the FCH Active Set is as the foundation of setting up RSCH branch, for example, the intensity level that reverse pilot intensity, reference pilot or reverse pilot intensity and forward pilot intensity are combined is as the foundation of setting up RSCH branch.

Below being example explanation the present invention as the foundation of setting up RSCH branch for wireless terminal in soft handover area with reverse pilot intensity.

Fig. 3 is the method flow diagram that the wireless terminal of the present invention in soft handover area set up RSCH branch, and its concrete steps are:

Step 300, wireless terminal are current at soft handover area, and a plurality of BTS that cover soft handover area measure the reverse pilot intensity of respective branch in the FCH Active Set respectively.

Respective branch is exactly the branch from the wireless terminal to BTS in the FCH Active Set in the described FCH Active Set.

Step 301, a plurality of BTS that cover in the soft handover area send to base station controller (BSC) under the wireless terminal with the reverse pilot intensity of respective branch in the FCH Active Set that measures respectively.

BSC under step 302, the wireless terminal is according to the size of each the reverse pilot intensity from wireless terminal to BTS branch in the FCH Active Set that receives, in the FCH Active Set each sorted to BTS branch from high to low from wireless terminal, select in the high FCH Active Set of ordering one or several branch as for this wireless terminal in RSCH branch that soft handover area is set up.

In step 300, the process that a plurality of BTS of covering soft handover area measure the reverse pilot intensity of respective branch in the FCH Active Set respectively is:

Measure the reverse pilot of respective branch in the FCH Active Set and make an uproar, and after carrying out filtering according to formula (1), obtain the reverse pilot intensity of respective branch in the FCH Active Set than (EcIo).

$\mathrm{out}\left(n\right)=\left(\frac{W-1}{W}\right)\·\mathrm{out}(n-1)+\left(\frac{1}{W}\right)\·\mathrm{in}\left(n\right)---\left(1\right)$

Wherein, the filtered average reverse pilot EcIo of the moment n of respective branch in out (n) the expression FCH Active Set; The instantaneous reverse pilot EcIo of moment n of respective branch in (n) the expression FCH Active Set; W represents filtering parameter.

The present invention below is described for a specific example.The present invention adopts schematic diagram shown in Figure 1, the soft handover area at the current place of assumed wireless terminal is covered by BTS1 and BTS2, wireless terminal belongs to the BSC administration, and Fig. 4 is the method embodiment flow chart that the wireless terminal of the present invention in soft handover area set up RSCH branch, and its concrete steps are:

Step 400, BTS1 measure the reverse pilot intensity of respective branch in the FCH Active Set, promptly measure the reverse pilot intensity from wireless terminal to BTS1 branch in the FCH Active Set; BTS2 measures respective branch in the FCH Active Set, promptly measures the reverse pilot intensity from wireless terminal to BTS2 branch in the FCH Active Set.

Step 401, BTS1 and BTS2 be respectively with the reverse pilot intensity of respective branch in the FCH Active Set that measures interface (Abis) link by BSC and BTS, sends to BSC with the speed of 20 milliseconds of every frames.

Step 402, BSC are carried out from high to low ordering according to each the reverse pilot intensity from wireless terminal to BTS branch in the FCH Active Set of receiving to the branch the FCH Active Set.As with making number one to BTS2 branch in the FCH Active Set from wireless terminal; With in the FCH Active Set from wireless terminal to the BTS1 branch row at second.

Step 403, BSC select branch in the highest FCH Active Set of ordering as first branch in the RSCH Active Set of being set up, be about in the FCH Active Set from wireless terminal to BTS2 branch as first branch the RSCH Active Set of being set up.

Step 404, for remaining each in the FCH Active Set from wireless terminal to BTS branch, judge one by one according to ordering from high to low:, change step 405 over to if the reverse pilot intensity of this branch is setovered less than set RSCH soft handover pilot frequency intensity with the difference of the reverse pilot intensity of the branch of ordering first; Otherwise, change step 406 over to.

Set RSCH soft handover pilot frequency intensity biasing is provided with according to demand.

After step 405, BSC also join this branch in the RSCH Active Set, judge whether number of branches in the RSCH Active Set selected equals the maximum branch number in the set RSCH Active Set, if, process ends then; Otherwise, continue execution in step 404.

Maximum branch number in the set RSCH Active Set is provided with according to demand.

Step 406, abandon this branch, process ends.

In the present invention, if BTS can not measure the reverse pilot intensity from wireless terminal to BTS branch in the FCH Active Set, then can be according to the reference pilot in the FCH Active Set that measures as the foundation of setting up RSCH branch from wireless terminal to BTS branch.Reference pilot is the pilot tone that arrives wireless terminal from wireless terminal to BTS branch at first in the FCH Active Set, can think best to BTS drop channel matter from wireless terminal in the strongest FCH Active Set of reference pilot.For example, frequently to cover the pilot tone fluctuation violent when the preceding reverse covering imbalance of soft handover area or overloading, when forward pilot intensity can not reflect the channel quality of the RSCH branch that is set up, can set up RSCH branch for the wireless terminal in soft handover area according to reference pilot.

In the present invention, also can combine the intensity level that obtains as the foundation of setting up RSCH branch according to the measured reverse pilot intensity that obtains of BTS and forward pilot intensity.The present invention can adopt formula: reverse pilot intensity+A * forward pilot intensity obtains intensity level, and wherein A is the weighted factor of forward pilot intensity, is generally less than 1.

The present invention also can be in the soft handover area at wireless terminal place, with in the FCH Active Set all from wireless terminal to BTS branch as being RSCH branch the RSCH Active Set set up of wireless terminal, though this method has been sacrificed the resource utilization of wireless communication system, can prevent that the RSCH branch that is set up from can not transmit the problem of reverse data.

Method provided by the invention has solved the problem for the bad channel quality of the RSCH branch that sets up at the wireless terminal of soft handover area, has improved the transmission rate of the reverse data that passes through the RSCH branch transmission of being set up.Method provided by the invention has reduced the foundation of unnecessary RSCH branch, has improved the resource utilization of wireless communication system.

The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being made within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (7)

1. a method of setting up reverse complemental channel RSCH branch is characterized in that, this method comprises:

A, more than one base station transceiver BTS send to base station controller BSC, the channel quality from wireless terminal to BTS branch in the intensity level reflection primary channel FCH Active Set that described reverse pilot intensity, reference pilot or reverse pilot intensity and forward pilot intensity combine with the intensity level that the reverse pilot intensity, reference pilot or the reverse pilot intensity that measure and forward pilot intensity combine;

The size of the intensity level that reverse pilot intensity, reference pilot or reverse pilot intensity that B, BSC basis is received and forward pilot intensity combine is to sorting from high to low to BTS branch from wireless terminal in the FCH Active Set, select in the highest one or more FCH Active Set of ordering from wireless terminal to BTS branch, as RSCH branch for this wireless terminal foundation.

2. the method for claim 1 is characterized in that, described measure when the reverse pilot intensity, the reverse pilot intensity process from wireless terminal to BTS branch in the described FCH of the measuring Active Set of steps A is:

Measure making an uproar than EcIo to the reverse pilot of BTS branch in the FCH Active Set, according to formula from wireless terminal $\mathrm{out}\left(n\right)=\left(\frac{W-1}{W}\right)\·\mathrm{out}(n-1)+\left(\frac{1}{W}\right)\·\mathrm{in}\left(n\right)$ After carrying out filtering, obtain the reverse pilot intensity in the FCH Active Set from wireless terminal to BTS branch;

Wherein, the filtered average reverse pilot EcIo of the moment n in out (n) the expression FCH Active Set from wireless terminal to BTS branch; The instantaneous reverse pilot EcIo of moment n in (n) the expression FCH Active Set from wireless terminal to BTS branch; W represents filtering parameter.

3. the method for claim 1, it is characterized in that, during the described intensity level that combines for reverse pilot intensity and forward pilot intensity that measures, the intensity level process that reverse pilot intensity from wireless terminal to BTS branch in the described FCH of the measuring Active Set of steps A and forward pilot intensity combine is:

Measure reverse pilot intensity and forward pilot intensity in the FCH Active Set respectively from wireless terminal to BTS branch, obtain the intensity level that reverse pilot intensity and forward pilot intensity combine according to formula reverse pilot intensity+A * forward pilot intensity, wherein A is the weighted factor of forward pilot intensity, and A is less than 1.

4. the method for claim 1 is characterized in that, in the highest one or more FCH Active Set of the described selection of step B ordering from wireless terminal to BTS branch, as RSCH ramifying be for this wireless terminal foundation:

B1, select in the FCH Active Set of ordering first from wireless terminal to BTS branch, as being first branch in the RSCH Active Set of this wireless terminal foundation;

B2, for the residue in the FCH Active Set from wireless terminal to BTS branch, according to ordering judge successively reverse pilot intensity, reference pilot or the reverse pilot intensity of described branch and intensity level that forward pilot intensity combines whether respectively with the RSCH Active Set in reverse pilot intensity, reference pilot or the reverse pilot intensity of first branch and the difference of the intensity level that forward pilot intensity combines less than the RSCH soft handover biasing that is provided with, if, then described branch is joined in the RSCH Active Set of building for this wireless terminal, change step B3 over to; Otherwise, abandon described branch, process ends;

B3, BSC are judged as the RSCH Active Set maximum branch number whether number of branches in the RSCH Active Set that this wireless terminal sets up reaches setting, if, process ends then; Otherwise, change step B2 over to, continue to select residue in the FCH Active Set from wireless terminal to BTS branch.

5. method as claimed in claim 4 is characterized in that, described measure when the reverse pilot intensity, the RSCH soft handover of described setting is biased to the biasing of RSCH soft handover pilot frequency intensity.

6. the method for claim 1, it is characterized in that, the intensity level that the described reverse pilot intensity of steps A, reference pilot or reverse pilot intensity and forward pilot intensity combine is the interface Abis link by BSC and BTS, sends to BSC's with the speed of 20 milliseconds of every frames.

7. the method for claim 1 is characterized in that, the described more than one BTS administration of steps A covers the soft handover area at wireless terminal place.

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