CN1225857C

CN1225857C - A speed control method in mobile communication system

Info

Publication number: CN1225857C
Application number: CNB021539758A
Authority: CN
Inventors: 伏玉笋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2002-12-05
Filing date: 2002-12-05
Publication date: 2005-11-02
Anticipated expiration: 2022-12-05
Also published as: CN1505301A

Abstract

The present invention puts forward a method for speed rate control in a mobile communication system. A filtered SIR error is judged by a base station controller for a data service. When the SIR error is larger than an upper threshold or is smaller than a lower threshold, a timer T1 is started up. If the SIR error is still larger than the upper threshold or is smaller than the lower threshold after T1 time, a link is illustrated to be in an abnormal state, the external loop power control of the link is then stopped and one level of channel bandwidth is increased or one level of channel bandwidth is reduced, and meanwhile, a timer T2 is started up. If the SIR error is still larger than the upper threshold or is smaller than the lower threshold within T2 time, one level of channel bandwidth is continuously increased or one level of channel bandwidth is reduced until the maximum or the minimum channel bandwidth is reached. The link can be returned to normal in the method of actively processing link abnormity by speed rate control by the present invention. System capacity is increased furthest under the condition that the quality of communication is guaranteed.

Description

Method of rate control in a kind of mobile communication system

Technical field

The present invention relates to wireless communication system, especially rate controlled in the CDMA digital cellular mobile communication systems

Technical field.

Technical background

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 disturbs system certainly, all mobile subscribers take same band and frequency, and exist nonideal correlation properties between the employed spreading code of each user, " 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.For the interference that rapid fading produces, can be by encoding, interweaving and reduce; And the interference that slow fading produces can only be controlled by power and overcomes.

Common CDMA power control techniques can be divided into open Loop Power control and closed power control.Power control section branch between terminal and the base transceiver station is also named inner loop power control, and the power control section branch between base transceiver station and the base station controller 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 regulates 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 need an exterior ring power control (Outer Loop Power Control, OLPC) mechanism, the quality (Block Error Rate of received signal (Block Error Rate normally according to communication, BLER), the error rate (Bit Error Rate, BER) and frame error rate (Fame Error Rate, FER)) adjust the desired value that interior ring is controlled, make system can satisfy the requirement of communication quality all the time with minimal power.Power control basic framework as shown in Figure 1 in the cdma 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 control; As the BLER/BER/FER that measures is higher than its desired value, then improves the SIRtarget value of inner loop power control.The basic framework of exterior ring power control as shown in Figure 2 in the cdma system.

When link is unusual, can cause the sir measurement value in continuing for some time, to be higher or lower than target SIR target value, that is to say that the actual measurement sir value no longer converges to target SIR target value.Such as closer from the base station as UE, SIR is also than higher when reaching descending minimum emissive power; Or distant as UE from the base station, when reaching maximum transmission power, SIR is also lower.After this thing happens, we claimed link to be in abnormality, and the inner loop power control fails was carried out exterior ring power control again and can be produced adverse influence on the contrary this moment.

Summary of the invention

Purpose of the present invention is exactly the globality from wireless access system, proposes to be applicable in a kind of mobile communication system the method for rate control of data service, under the situation that guarantees communication quality, improves power system capacity to greatest extent.

Method of rate control may further comprise the steps in a kind of mobile communication system:

A, base transceiver station report signal interference ratio deviation value (SIR _Error) measured value, described SIR _Error=SIR-SIR _Target-ave, wherein SIR is the signal-to-interference ratio measurement value, SIR _Target-aveBe signal interference ratio desired value SIR _TargetMean value on a period of time;

B, SIRerror is carried out filtering, obtain this filter value;

Described filtering is to carry out in such a way: F _n=(1-a) F _N-1+ aM _n, wherein Fn is this filter value through Filtering Processing; Fn-1 is filter value last time through Filtering Processing; Mn is the current SIRerror measured value that receives from physical layer, a=1/2 ^(k/2), k is filter factor, is the parameter that need determine according to the SIRerror data characteristic;

C, when SIRerror greater than predefined upper threshold or less than predefined Xiamen limit value, start first timer, SIRerror is still greater than predefined upper threshold or less than predefined Xiamen limit value after the predetermined very first time, judge that then link is in abnormality, stop the exterior ring power control of this link;

If d SIRerror then increases one-level with channel width greater than predefined upper threshold, if SIRerror then reduces one-level with channel width less than predefined Xiamen limit value;

E, start second timer simultaneously, if SIRerror is still greater than predefined upper threshold or less than predefined Xiamen limit value after predetermined second time, then enter steps d, maximum or minimum channel bandwidth or described link-recovery are normal up to reaching.

Described upper threshold, Xiamen limit value, the very first time, second time are determined according to the actual conditions and the operating environment of communication system.

Adopt the present invention, can through-rate control the active process abnormal link, made it to recover normal, improved communication quality, utilized Radio Resource better, under the situation that guarantees communication quality, improved power system capacity to greatest extent.

Description of drawings

Fig. 1 is a uplink power control schematic diagram in the cdma system;

Fig. 2 is an exterior ring power control schematic diagram in the cdma system;

Fig. 3 is a rate controlled flow chart of the present invention.

Embodiment

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described.

As shown in Figure 3, the measured value of base transceiver station SI reporting Rerror, base transceiver station SI reporting R _Error, use formula SIR _Error=SIR-SIR _Target-aveCalculate SIR _Error, the same with SIR, SIR _Target-ave=SIR _TargetMean value on a period of time.

And this numerical value carried out Filtering Processing, the filter processing method of measured value in base transceiver station is: F _n=(1-a) F _N-1+ aM _n, wherein: Fn is that the measurement result of renewal is this filter value through Filtering Processing; Fn-1 is through Filtering Processing, and last old measurement result of a moment is filter value last time; Mn is the nearest measured value that receives from physical layer, is this measured value, a=1/2 ^(k/2), k is filter factor, is the parameter that needs are determined according to real SIRerror data characteristic.

For data service, base station controller is by judging whether current link is in abnormality.According to filtered SIRerror,, start timer T1 as SIRerror during greater than Upper threshold.At T1 after the time, if SIRerror also greater than this thresholding, this illustrates that this link is in abnormality, stops the external circule power control of this link so, promptly no longer adjusts the SIRtarget value of inner ring link, waits for that link-recovery is normal, recovers its normal OLPC again.Following unusually at this link, for data service, channel width is increased one-level.Start timer T2 simultaneously, if in the time of T2, if SIRerror also greater than this thresholding, then continues channel width is increased one-level, till reaching the maximum channel width that allows.In the rate controlled process of using based on SIRerror, stop common DCCC algorithm based on buffering area situation and air interface situation.

For data service,,, start timer T1 as SIRerror during less than Lower Threshold according to filtered SIRerror.At T1 after the time, if SIRerror also less than this thresholding, this illustrates that this link is in abnormality, stops the external circule power control of this link so, promptly no longer adjusts the SIRtarget value of inner ring link, waits for that link-recovery is normal, recovers its normal OLPC again.Following unusually at this link, for data service, channel width is reduced one-level.Start timer T2 simultaneously, if in the time of T2, if SIRerror also less than this thresholding, then continues channel width is reduced one-level, till reaching the minimum channel width that allows.In the rate controlled process of using based on SIRerror, stop common DCCC algorithm based on buffering area situation and air interface situation.

For Upper threshold, Lower Threshold, T1 and T2 parameter, need determine according to actual conditions and its operating environment of communication system.

For data service, between communication period, because the variation of service source data rate was originally distributed to this professional channel capacity and may be become no longer suitable, at this moment be necessary to redistribute channel resource to business, carry out channel and reshuffle according to current service traffics.Dynamic channel configuration control (DCCC:DynamicalChannel Configuration Control) algorithm proposes in order to solve this problem that need reshuffle channel width owing to the service source rate variation.The service source rate requirement is exactly the bandwidth demand of current connection, and promptly current connection needs great channel capacity to send the data of oneself smoothly.What can reflect the service source rate requirement is the state of the buffering area of service source, by measuring to data volume in the buffering area or to the situation that takies of buffering area, just can accurately draw the source data rate demand in conjunction with current channel capacity, the up employing throughput of air interface situation reflects (throughput is the transmission rate of reality in the transmission channel and the ratio of the maximum rate that channel is disposed).The descending MACD of having carries out TFC according to the descending sign indicating number of NodeB transmitting power measurement report and selects, and judges and reports downlink air interface limited conditions.After high level receives the traffic carrying capacity report, just whether carry out the judgement that dynamic channel is reshuffled according to event type in the report.If the traffic carrying capacity that measures surpasses Upper threshold, and current at the next needs of dedicated channel situation with reference to the air interface situation, if air interface is not limited, just have more jumbo channel (carrying out source speed according to traffic carrying capacity estimates) than current channel for this business (or user) configuration, to satisfy user's business demand better, then do not reshuffle if air interface is restricted, even because disposed bigger channel capacity, but abominable air interface situation can limit transmission rate, make professional actual speed still be in original speed, not rising, is the waste that has caused channel resource on the contrary; If currently then directly carry out dynamic channel at common signal channel and reshuffle according to the measuring business volume Report Type.If the traffic carrying capacity that measures is lower than Lower Threshold, just have littler channel (carrying out source speed according to traffic carrying capacity estimates) than the channel of current use for this business (or user) configuration, thereby, improve usage factor of system resource for system keeps more Radio Resource.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with the people of this technology in the disclosed technical scope of the present invention; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1, method of rate control in a kind of mobile communication system is applicable to data service, it is characterized in that may further comprise the steps:

A, base transceiver station report signal interference ratio deviation value SIR _ErrorMeasured value, described SIR _Error=SIR-SIR _Target-ave, wherein SIR is the signal-to-interference ratio measurement value, SIR _Target-aveBe signal interference ratio desired value SIR _TargetMean value on a period of time;

B, SIRerror is carried out filtering, obtain this filter value, wherein, described filtering is to carry out in such a way:

F _n＝(1-a)·F _n-1+a·M _n，

Wherein, Fn is this filter value through Filtering Processing; Fn-1 is filter value last time through Filtering Processing; Mn is the measured value of the current SIRerror that receives from physical layer, a=1/2 ^(k/2), k is filter factor, is the parameter that need determine according to the SIRerror data characteristic;

2, method of rate control in a kind of mobile communication system as claimed in claim 1 is characterized in that: described upper threshold, Xiamen limit value, the very first time, second time are determined according to the actual conditions and the operating environment of communication system.