CN100373804C - Method of outer ring power control for combined service of WCDMA system - Google Patents

Abstract

The present invention relates to an exterior ring power control in a WCDMA system, particularly to an exterior ring power control method of a combined service, which comprises the following steps: S1, the system judges the states of a service transmission channel, if at least one service transmission channel is not DTX, then go to step S2, else go to step S3; S2, the system controls exterior ring power in a certain period based on BLER or / and FER or/ and BER corresponding to a private DPDCH, and the period is the exterior ring power control cycle of the system; S3, the system controls the exterior ring power in a certain period based on BER corresponding to DPCCH, and the period is the exterior ring power control period of the system. In the method, every service can meet the requirements of a BLER target value in combined service under the condition of different communication channel environments and power biases. When different transmission formats are combined, every service can satisfy the requirements of the BLER target value.

Description

The professional outer-loop power controlling method of WCDMA system in combination

Technical field

The present invention relates to the WCDMA system, particularly WCDMA system outer-loop power controlling method.

Background technology

CDMA is a kind of spread spectrum technic.Spread spectrum technic mainly applies to military communication in the early stage, because its remarkable performance also obtains to use widely in the commercial communication field, has had commercial cdma cellular mobile communication system to operate in the telecommunications network now.

Cdma system is one, and all mobile subscribers take same band and frequency, and exist nonideal correlation properties between the employed spreading code of each user from disturbing system, and " near-far interference " problem is outstanding especially.Therefore the big young pathbreaker of user emission power directly influences the total capacity of system, thereby makes power control techniques become one of of paramount importance core technology in the cdma system.The target of power control is exactly under the condition that guarantees user communication quality in the cdma system, makes user's transmitting power as far as possible little.Because the capacity of cdma system depends on the size of interference, the multiple access Recombinant Interferon that reduces system increases the capacity of system greatly.The interference that produces for rapid fading can be by coding, interweave and reduce, and the interference that slow fading produces can only be controlled by power and overcomes.

As shown in Figure 1, Fig. 1 is power control basic framework figure in the cdma system, and common CDMA power control techniques can be divided into open Loop Power control and closed power control.Power control section branch between UE and the NodeB is also named inner loop power control, and the power control section branch between NodeB and the RNC is also named exterior ring power control.The basic functional principle of open Loop Power control is to be the principle of constant according to the long-pending of user's received power and transmitting power, measures the size of received power in advance, and determines the size of transmitting power thus.The open Loop Power control of travelling carriage is meant the process that travelling carriage is regulated transmission power of mobile station according to the base station signal strength that receives.The signal power that receives is strong more, and the transmitting power of travelling carriage should be more little, its objective is that making all travelling carriages arrive signal of base station power equates, in order to avoid influence the reception of spectrum CDMA system to the sign indicating number sub-signal because of " near-far interference "; The open Loop Power control of base station is meant the process that base station transmitting power is regulated according to the signal quality information of the transmission of each travelling carriage that receives in the base station, its objective is to make travelling carriage under the condition that guarantees communication quality, and the transmitting power of base station is minimum.Open Loop Power control is used for determining user's Initial Trans, or the transmission power adjustment the during sudden change of user's received power.Open Loop Power control is mainly used to overcome shade and path loss.Open Loop Power control reckons without the asymmetry of uplink and downlink channel electric wave power, thereby its accuracy is difficult to be guaranteed.Closed power control is head it off well.Closed power control is used to overcome the decline that Doppler frequency produces.It is to have identical power when making each mobile station signal reach the base station that the number of mobile stations (power system capacity) that can call out emission simultaneously reaches the desired condition of maximum, and should be in that to satisfy under the prerequisite of link performance signal power as far as possible little.By the measurement estimation of signal interference ratio SIR and the contrast of signal interference ratio desired value (SIRtarget), determine power control bit information, by channel power control bit information is sent to transmitting terminal then, and regulate the size of transmitting power according to this, this desired value is exactly the correct required signal interference ratio of demodulation useful signal.Yet under different multi-path environment (translational speed of travelling carriage and the number of multipath etc.), this value is different.Therefore the mechanism that needs an exterior ring power control (OLPC:Outer Loop Power Control), adjust the desired value that interior ring is controlled according to the quality (the normally Block Error Rate of received signal (BLER:Block Error Rate), the error rate (BER:Bit Error Rate) and frame error rate (FER:Fame Error Rate)) of communication, make system can satisfy the requirement of communication quality all the time with minimal power.

As shown in Figure 2, Fig. 2 is the basic framework figure of exterior ring power control in the WCDMA system.Because one the link final mass is that BLER/BER/FER by this link is determined that the thinking of OLPC is exactly the BLER/BER/FER of monitoring link, makes the BLER/BER/FER of this link approach its desired value, final purpose is the quality of reception that guarantees link.As the BLER/BER/FER that measures is lower than its desired value, then reduces the SIRtarget value of inner loop power; As the BLER/BER/FER that measures is higher than its desired value, then improves the SIRtarget value of inner loop power.

In the WCDMA system, a user can have a plurality of business, and each business all needs to satisfy the requirement to communication quality.This patent changes with better tracking environmental at the exterior ring power controlling schemes (also being applicable to single service conditions certainly) of this composite service situation design, guarantees communication quality, improves power system capacity.

The prior art scheme is carried out exterior ring power control for the BLER/BER/FER based on a transmission channel business, and other transmission channel or professional communication quality through-rate coupling satisfy.

In the practical application, prior art has following shortcoming:

1, the rate-matched of same business is under different channel circumstances and power bias condition, and the transmission channel or the professional BLER of non-exterior ring power control are different, the situation of BLER desired value occurred not satisfying;

2, the transmission channel or the professional BLER of the non-exterior ring power control when different transpost formats makes up of same service rate coupling are different, the situation of BLER desired value occurred not satisfying.

Summary of the invention

Technical problem to be solved by this invention is:

1, the rate-matched that solves same business is under different channel circumstances and power bias condition, and each business all can satisfy the problem that the BLER/BER/FER desired value requires in the composite service;

2, the rate-matched that solves same business is when different transpost formats makes up, and each business all can satisfy the problem that the BIER/BER/FER desired value requires in the composite service.

The professional outer-loop power controlling method of a kind of WCDMA system in combination of the present invention, described composite service comprises at least two business that are distributed in different transmission channels, comprises the following steps:

S1: the state of the transmission channel that each is professional is judged by system, when having the transmission channel right and wrong DTX of a business at least, carries out step S2; Otherwise, carry out step S3; S2: system based on the BLER of special-purpose DPDCH correspondence or/and FER or/and BER carries out exterior ring power control with some cycles, the described cycle is the exterior ring power control cycle of system; S3: system carries out exterior ring power control based on the BER of DPCCH correspondence with some cycles, and the described cycle is the exterior ring power control cycle of system.

Described method also comprises the step of RNC difference different business: when different service integrations was on same transmission channel, RNC distinguished with logical channel number, judged professional transmission state then.

Described step S1 comprises the following steps:

S11:MAC layer setup parameter N, N1, N2, wherein: N is a TTI number of adjusting the required transmission of target SIR in the exterior ring power control, the exterior ring power control adjustment cycle that is specially system rounds after divided by TTI; N1 is the TTI number during the non-DTX; N2 is the TTI number during the DTX; N1+N2=N; The S12:MAC layer is the cycle N1, N2 to be counted with N; The S13:MAC layer is according to the state of described each the professional transmission channel of count results judgement of N1, and concrete determination methods is: when N1 was not equal to zero, the transmission channel that then has a business at least was non-DTX state, carries out step S2; Otherwise, carry out step S3.

Described step S2 comprises the following steps:

S21: calculate the signal interference ratio desired value of every transmission channel, described signal interference ratio desired value according to one of in the formula 1～3 or combination in any calculate:

$\widehat{\mathrm{SIR}}(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{BLERmeas}(n+1,i)}{\mathrm{BLERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(1\right)$

$\widehat{\mathrm{SIR}}(n+1.i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{BERmeas}(n+1,i)}{\mathrm{BERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(2\right)$

$\widehat{\mathrm{SIR}}(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{FERmeas}(n+1,i)}{\mathrm{FERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(3\right)$

Wherein, i: i bar transmission channel;

I bar transmission channel is in the signal interference ratio desired value of n+1 exterior ring power control cycle; SIR (n): the signal interference ratio desired value of n exterior ring power control cycle;

Stepdown (i): the signal interference ratio desired value downward modulation step-length of i bar transmission channel; Factor (i): the adjustment factor of i bar transmission channel; BLERtarget (i): the BLER desired value of i bar transmission channel;

BERtarget (i): the BER desired value of i bar transmission channel; FERtarget (i): the FER desired value of i bar transmission channel; BLERmeas (n+1, i): i bar transmission channel is at the BLER of n+1 exterior ring power control cycle measured value; BERmeas (n+1, i): i bar transmission channel is at the BER of n+1 exterior ring power control cycle measured value; FERmeas (n+1, i): i bar transmission channel is at the FER of n+1 exterior ring power control cycle measured value;

S22:RNC chooses the maximum in the result of calculation, that is:

Export to the base station as new signal interference ratio desired value.

Described step S3 comprises the following steps:

S31:RNC is the BER that the cycle receiving data frames reports in each TTI with N, is designated as BER1 respectively, BER2 ... BERN; S32:RNC asks mean value BERm=(BER1+...+BERN)/N of BER; S33:RNC is according to the signal interference ratio desired value of the selected output of mean value, and concrete grammar is: work as BERm〉BERtarget+BERtarget1, improve xdb with the signal interference ratio desired value; When BERm＜BERtarget-BERtarget2, the signal interference ratio desired value is reduced ydb, described x db and ydb are less than the step-length of inner loop power control; The BERtarget1:BER Upper threshold; The BERtarget2:BER Lower Threshold; The mean value of BERm: BER.

When business was composite service, the described cycle was selected maximum in each professional exterior ring power control cycle by system; When this business was composite service, x db got each professional corresponding maximum, and y db gets each professional corresponding minimum value; The BER desired value of composite service is got the minimum value of single professional BER desired value; When this business was composite service, BERtarget1, BERtarget2 got each professional corresponding maximum.

Application the invention has the beneficial effects as follows: 1, under different channel circumstances and power bias condition, each business in the composite service all can satisfy the requirement of BLER desired value; 2, when different transpost formats makes up, each business in the composite service all can satisfy the requirement of BLER desired value.

Description of drawings

Below with specific embodiment and be described with reference to the accompanying drawings the present invention.

Fig. 1 is power control basic framework figure in the cdma system;

Fig. 2 is the basic framework figure of exterior ring power control in the WCDMA system;

Fig. 3 is the structure chart of the method for the invention exterior ring power control.

Embodiment

Judge the state of each business on all transmission channels.Concrete judgement principle as shown in Figure 3, wherein N is TTI (Transmission Time Interval) number of adjusting the required transmission of target SIR in the exterior ring power control, N rounds then to determine that N1 is the TTI number during the non-DTX that with exterior ring power control adjustment cycle N2 is the TTI number during the DTX divided by TTI.N1+N2=N here has following three kinds of situations like this:

(a) N1 ≠ 0, N2=0, then this moment corresponding non-DTX situation, carry out exterior ring power control based on the BLER/FER/BER of DPDCH correspondence.

(b) N1 ≠ 0, N2 ≠ 0, then this moment, corresponding DTX and non-DTX mixed situation, carried out exterior ring power control by the BLER/FER/BER based on the DPDCH correspondence.

(c) N1=0, N2 ≠ 0, then this moment corresponding DTX situation, the BER that carries out based on the DPCCH correspondence carries out exterior ring power control.

The MAC layer is the cycle N1 and N2 to be counted respectively with N, N back zero clearing of every meter.Such as: in 6 TTI data are arranged in N=10 the TTI, do not have data in 4 TTI, N1=6 then, N2=4.

When each service distribution is on different transmission channels, if having the transmission channel of a business at least is non-DTX state (admixture that contains non-DTX and DTX), other professional transmission channel is the DTX state, then by non-DTX state based on BLER or/and FER or/and BER carries out power control, when having only all professional transmission channels to be the DTX state, just adopt the exterior ring power controlling mechanism during the DTX, also promptly carry out exterior ring power control with the BER of DPCCH.If different service integrations is on same transmission channel the time, RNC distinguishes different business by logical channel number, the same exterior ring power control procedure when carrying out with each service distribution then on different transmission channels.

The method of carrying out exterior ring power control based on the corresponding BLER/FER/BER of DPDCH under the non-DTX state is specially:

Calculate the target signal interference ratio SIR of every channel.

The present invention adopts following formula to calculate the sir target value of every transmission channel:

$\widehat{\mathrm{SIR}}(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{BLERmeas}(n+1,i)}{\mathrm{BLERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(1\right)$

Wherein i represents certain bar transmission channel; Step: step-length; Factor: adjust the factor; Step and factor depend on professional algorithm parameter.Also B parameter ER/FER can be brought into formula 1 and calculate, utilize result of calculation to control then according to following method.

RNC chooses the maximum in the result of calculation, that is:

Export to base station node B as new signal interference ratio desired value.

When each service distribution is on different transmission channels, be the communication quality that guarantees that all are professional, under the non-DTX state, have only when all transmission channels all will be begged to surrender the sir target value and just reduce, therefore other situation sir target value that all raises selects maximum as new signal interference ratio desired value.

Can also adopt other control methods in the prior art, for example: if BLERmeas〉BLERtarget, SIRtarget (n+1)=SIRtarget (n)+0.4 then, if BLERmeas＜BLERtarget, SIRtarget (n+1)=SIRtarget (n)-0.1 then, wherein BLERmeas is the measured value of BLER.

The method of controlling based on the BER of DPCCH correspondence under the DTX state is specially:

If the BER that reports in the Frame is respectively BER1, BER2 ..., BERN, the BERm=that averages (BER1+...+BERN)/N works as BERm〉BERtarget+BERtarget l, so target SIR is improved xdb; When BERm＜BERtarget-BERtarget2, so target SIR is reduced ydb.Xdb, ydb should be less than the step-lengths of inner loop power control, it and BERtargetl, BERtarget2 (BERtargetl:BER Upper threshold, the BERtarget2:BER Lower Threshold) all be to depend on professional algorithm parameter, x db and y db are not unique value, but by the definite parameter of system emulation.

The selection principle of exterior ring power Control Parameter is under the composite service:

1, the exterior ring power control cycle of composite service is got the maximum in each business;

2, the xdb of composite service gets the maximum of the xdb of each professional correspondence, and ydb gets the minimum value of the ydb of each professional correspondence;

3, the BER desired value of composite service is got the minimum value of single professional BER desired value;

4, the BERtarget1 of composite service, BERtarget2 get maximum among each professional corresponding BERtarget1 and the maximum among the BERtarget2.

The beneficial effect that application the method for the invention can obtain is:

Under different channel circumstances and power bias condition, each business in the composite service all can satisfy the requirement of BLER desired value; When different transpost formats made up, each business in the composite service all can satisfy the requirement of BLER desired value.

Claims (9)

1. the professional outer-loop power controlling method of a WCDMA system in combination, described composite service comprises at least two business that are distributed in different transmission channels, it is characterized in that comprising the following steps:

S1: the state of the transmission channel that each is professional is judged by system, when having the transmission channel right and wrong DTX of a business at least, carries out step S2; Otherwise, carry out step S3;

S2: system based on the BLER of special-purpose DPDCH correspondence or/and FER or/and BER carries out exterior ring power control with some cycles, the described cycle is the exterior ring power control cycle of system;

S3: system carries out exterior ring power control based on the BER of DPCCH correspondence with some cycles, and the described cycle is the exterior ring power control cycle of system.

2. the method for claim 1 is characterized in that: the step that also comprises RNC difference different business: when different service integrations was on same transmission channel, RNC distinguished with logical channel number, judged professional transmission state then.

3. the method for claim 1 is characterized in that described step S1 comprises the following steps:

S11:MAC layer setup parameter N, N1, N2, wherein: N is a TTI number of adjusting the required transmission of target SIR in the exterior ring power control, the exterior ring power control adjustment cycle that is specially system rounds after divided by TTI; N1 is the TTI number during the non-DTX; N2 is the TTI number during the DTX; N1+N2=N;

The S12:MAC layer is the cycle N1, N2 to be counted with N;

The S13:MAC layer is according to the state of described each the professional transmission channel of count results judgement of N1, and concrete determination methods is: when N1 was not equal to zero, the transmission channel that then has a business at least was non-DTX state, carries out step S2; Otherwise, carry out step S3.

4. the method for claim 1 is characterized in that described step S2 comprises the following steps:

S21: calculate the signal interference ratio desired value of every transmission channel, described signal interference ratio desired value according to one of in the formula 1～3 or combination in any calculate:

$S\hat{I}R(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{BLERmeas}(n+1,i)}{\mathrm{BLERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(1\right)$

$S\hat{I}R(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{BERmeas}(n+1,i)}{\mathrm{BERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(2\right)$

$S\hat{I}R(n+1,i)=\mathrm{SIR}\left(n\right)+(\frac{\mathrm{FERmeas}(n+1,i)}{\mathrm{FERt}\arg \mathrm{et}\left(i\right)}-1)\×\mathrm{Stepdown}\left(i\right)\×\mathrm{factor}\left(i\right)\·\·\·\left(3\right)$

Wherein, i: i bar transmission channel;

I bar transmission channel is in the signal interference ratio desired value of n+1 exterior ring power control cycle:

SIR (n): the signal interference ratio desired value of n exterior ring power control cycle; Stepdown (i): the signal interference ratio desired value downward modulation step-length of i bar transmission channel;

Factor (i): the adjustment factor of i bar transmission channel;

BLERtarget (i): the BLER desired value of i bar transmission channel;

BERtarget (i): the BER desired value of i bar transmission channel;

FERtarget (i): the FER desired value of i bar transmission channel;

BLERmeas (n+1, i): i bar transmission channel is at the BLER of n+1 exterior ring power control cycle measured value;

BERmeas (n+1, i): i bar transmission channel is at the BER of n+1 exterior ring power control cycle measured value:

FERmeas (n+1, i): i bar transmission channel is at the FER of n+1 exterior ring power control cycle measured value:

S22:RNC chooses the maximum in the result of calculation, that is: $\mathrm{SIR}(n+1)=\underset{i}{\mathrm{Max}}\left\{S\hat{I}R(n+1,i)\right\}$ , export to the base station as new signal interference ratio desired value.

5. the method for claim 1 is characterized in that described step S3 comprises the following steps:

S31:RNC is the BER that the cycle receiving data frames reports in each TTI with N, is designated as BER1 respectively, BER2 ... BERN:

S32:RNC asks mean value BERm=(BER1+...+BERN)/N of BER;

S33:RNC is according to the signal interference ratio desired value of the selected output of mean value, and concrete grammar is: as BERm＞BERtarget+BERtarget1, the signal interference ratio desired value is improved xdb; When BERm＜BERtarget-BERtarget2, the signal interference ratio desired value is reduced ydb, described xdb and ydb are less than the step-length of inner loop power control; The BERtarget1:BER Upper threshold; The BERtarget2:BER Lower Threshold; The mean value of BERm:BER.

6. the method for claim 1 is characterized in that: when business was composite service, the described cycle was selected maximum in each professional exterior ring power control cycle by system.

7. method as claimed in claim 5 is characterized in that: when this business was composite service, xdb got each professional corresponding maximum, and ydb gets each professional corresponding minimum value.

8. method as claimed in claim 5 is characterized in that: the BER desired value of composite service is got the minimum value of single professional BER desired value.

9. method as claimed in claim 5 is characterized in that: when this business was composite service, BERtarget1, BERtarget2 got each professional corresponding maximum.

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