CN1299441C

CN1299441C - A method for controlling inter-frequency load balancing in WCDMA system

Info

Publication number: CN1299441C
Application number: CNB2004100373450A
Authority: CN
Inventors: 黄胜华; 李大鹏; 程翔
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2004-04-29
Filing date: 2004-04-29
Publication date: 2007-02-07
Anticipated expiration: 2024-04-29
Also published as: CN1571292A

Abstract

The present invention discloses a balancing control method for loads among frequencies in a broadband code division multiple access system. The present invention comprises the following processing procedures that RNC acquires information reflecting the load conditions of subzones from Node B at definite time; RNC decides whether balancing action is necessary to be executed or not according to parameters of preset load thresholds, actually measured loads of the subzones and loads of covered alien frequency subzones; if the balancing action to the alien frequency subzones is decided to be executed, partial UE is selected in the subzones, and an order of direct-cut operation among the frequencies is transmitted to the UE; the UE executing the direct-cut operation in the alien frequency subzones returns the message of completion. The method of the present invention can be used for well guaranteeing that a WCDMA system selects and switches the partial UE into the same covering alien frequency subzones with low loads for service acceptance; the loads of a plurality of same covering alien frequency subzones well realize the balance of the loads, so the maximization of the capacity of the whole system is realized, and the subsequent UE can be smoothly and conveniently accessed.

Description

Load balance control method between the frequency in a kind of broadband CDMA system

Technical field

The present invention relates to a kind of load equalization method in Wideband Code Division Multiple Access (WCDMA) (the Wideband Code Division Multiple Access) system (hereinafter to be referred as WCDMA), particularly, promptly utilize the situation that receives total wideband power (Received Total Wide band Power) (hereinafter to be referred as RTWP) and/or emission carrier power (TransmittedCarrierPower) (hereinafter to be referred as TCP) to determine the concrete grammar that load balancing is controlled between the frequency of system in running according to the sub-district and with the load measurement value of coverage cell.

Background technology

Extensive use and fast development along with mobile communcations system, a lot of key technologies in the mobile system also are gradually improved, when realizing user's proper communication, also must consider how to obtain best performance, obtain for system and subscriber equipment and can both obtain gratifying preferably effect, from the angle of system, wish to insert as far as possible more user.

In the WCDMA system, subscriber equipment (User Equipment,) (hereinafter to be referred as UE) in the process that moves, residing wireless environment is engraved in when being and is changing, when UE degenerates away from base station or wireless environment, if still keep original speed rates, in order to guarantee its service quality QoS (Quality of Service), under the effect of closed power control, the base station will inevitably send signal with bigger power, and the capacity of system also can change thereupon.

The WCDMA system has compared many special characters with other system (as gsm system and cdma system), soft capacity, support variable Rate business are the big features of one, if can make UE in the less sub-district of load, receive service by adequate measure, for system, the access of follow-up UE in the higher sub-district that can guarantee better to load; For the user, can obtain relative good quality of service.For adopting with the zone that covers alien-frequency district, a plurality ofly constituted the total capacity that should the zone can reach with the capacity sums that cover different carrier cell, how to realize the overloading maximization of regional capacity frequently, be to be worth a problem studying.

Number of patent application is 00127302.7 Chinese patent application " the pretreated method of load balance in a kind of mobile communication system ", illustrated in mobile communication system, by measuring the load condition of adjacent each sub-district, revise system information parameters, promptly control the parameter that the user selects the sub-district, in the relatively low sub-district of load, insert thereby reach the guiding user.The described thought of this patent application, can only be used for the processing of co-frequency cell, at be the potential user of connecting system not as yet, and handle for the what state that has alien-frequency district, this patent application does not have and can be described, how to handle for the user of connecting system, also do not have corresponding processing method in this patent application.

Summary of the invention

The objective of the invention is to solve the load balancing specific implementation method that does not have in the prior art standard at the WCDMA system, particularly at possessing with covering alien-frequency district, and proposed in a kind of system running based on load equalization method between the frequency of load measurement.

In 3GPP TS 25.331 standards, stipulated that the public-measurement report reporting of NodeB in the WCDMA system can be selected dual mode: periodic report and Event triggered report.This method is primarily aimed at the periodic report mode and is described, but reports under the mode suitable equally in Event triggered.

Load balance control method of the present invention comprises the steps:

(1) radio network controller (RNC) (Radio Network Controller) regularly obtains reflection cell load condition information from Node B;

(2) radio network controller (RNC) is according to the load of predefined load threshold parameter, sub-district actual measurement and with the load that covers alien-frequency district, and whether decision is necessary to carry out balanced action;

(3) if the equilibrium action to alien-frequency district is carried out in decision, then in this sub-district, select the part user equipment (UE), and send the order of direct-cut operation between frequency to these UE;

(4) user equipment (UE) of execution switching returns in alien-frequency district and finishes message.

Radio network controller (RNC) obtains the reception broadband power RTWP and the emission carrier power TCP value of cell load situation in step (1), comprises the steps;

(1.1) RNC sends at sub-district public-measurement control command to NodeB, require to measure and receive broadband power RTWP and/or launch carrier power TCP value, and set the condition report, for the periodic report mode, the cycle that the needs setting reports etc., for reporting events, the thresholding that the needs setting reports, triggered time etc.;

(1.2) NodeB is to the up reception broadband power RTWP of respective cell and/or emission carrier power TCP value, during report condition in reaching the measurement control order that RNC sends, reports to RNC;

(1.3) RNC stores the result that NodeB reports, and uses during for needs.

In above-mentioned steps (2), radio network controller (RNC) inquiry and more current load condition with a plurality of sub-districts that cover, in conjunction with predefined threshold parameter, whether decision is necessary to carry out balanced action, for the judgement of load condition following several method can be arranged:

(2.1) be limited as in the main system at up direction, can only select the reception broadband power RTWP that adopts up direction to receive, as duty ratio reference between each sub-district.

(2.2) be limited as in the main system at down direction, can only select to adopt down direction emission carrier power TCP value, as duty ratio reference between each sub-district.

(2.3) in the system that the uplink and downlink direction need be taken all factors into consideration, the reception broadband power RTWP and the down direction emission carrier power TCP value that can adopt up direction to receive simultaneously are as duty ratio reference between each sub-district.

According to the treating method of setting, there is being cell load to be higher than it when covering the threshold value of a setting of alien-frequency district, balanced action is carried out in decision.

In addition, also can consider when cell load is under certain thresholding, no matter with the load condition that covers alien-frequency district how each do not carry out balanced action.

In above-mentioned steps (3), RNC selects suitable UE according to the decision of being made in the step (2), sends reconfiguration message with direct-cut operation between carrying out frequently to it, may comprise following content in the message: A. cell frequency information; B. the scrambling code information of sub-district; C. the resource information of being distributed.Concrete selection UE can have but be not limited to following several method:

(3.1) selection is not in the UE of soft changing state.

(3.2) select QoS (QoS) to require lower UE, consider priority, delay requirement etc.

(3.3) select the lower UE of service rate.

Method of the present invention is simple, logic is reasonable, efficient is high, can guarantee well that the WCDMA system is in system's running, select part UE to cut acceptance service to the lower same covering alien-frequency district of load as early as possible, make a plurality of loads realize the equilibrium of loading preferably with the different carrier cell of covering, thereby realize the maximization of overall system capacity, also can make things convenient for the smooth access of follow-up UE.In addition, the method for the invention can also be avoided the frequent equilibrium treatment that may occur from two aspects.Be by setting a thresholding on the one hand, under this thresholding, with the load condition that covers alien-frequency district how no matter, all needn't make equilibrium treatment, thinking has preferably ability admit new user this moment in the sub-district of higher load relatively; On the other hand, two sub-districts do duty ratio in, can set a sluggish thresholding, just really do the processing of load balancing when the load in two sub-districts exceeds this sluggishness thresholding, thereby safeguard the current service quality that has inserted UE to greatest extent.

Description of drawings

Fig. 1 is the general flow chart of load balancing between the embodiment of the invention one system operation time-frequency;

Fig. 2 is the message flow chart of RNC and Node B during load balancing between system of the present invention operation time-frequency;

Fig. 3 is the message flow chart between RNC and UE during load balancing between system of the present invention operation time-frequency;

Fig. 4 is the general flow chart of load balancing between embodiment of the invention two system operation time-frequency.

Embodiment

The present invention makes full use of the measurement result that NodeB reports in the WCDMA system, in RNC, according to the current area load condition that reports and with the load that covers alien-frequency district, whether the UE that comprehensive decision is being carried out in the service communication is necessary balanced to the same coverage cell of other different carrier frequency.

Be described in further detail below in conjunction with the enforcement of accompanying drawing technical scheme:

Use the method for the invention in the WCDMA system, in measurement control order, what adopt for public-measurement is the periodic report scheme, reports mode that the important references meaning is also arranged for Event triggered.

The flow process of the method for the invention core concept as shown in Figure 1, as can be seen from Figure 1:

Step 101, RNC sends public-measurement control command (Common Measurement InitiationRequest) to Node B, requires Node B period measurement and reports RTWP and/or the measured value of TCP; In sending measurement control order, also comprise the gap (Report Periodicity), filtration coefficient (Measurement FilterCoefficient) of periodic report etc.;

Step 102, NodeB receives the public-measurement control command that RNC sends, and measures reporting measurement result when report condition satisfies as requested;

Step 103, after RNC receives reported result, RTWP relevant and/or TCP value that storage NodeB reports with each sub-district; RTWP is an amount of situation that directly reflects the uplink interference of sub-district, and TCP is an amount that directly reflects the cell downlink transmitting power, under the condition that plot planning is determined, two measuring amount can represented the load condition of the uplink and downlink of a sub-district respectively;

Step 104, RNC is receiving the metrical information of cell load (RTWP and/or TCP) afterwards, compare each with the load condition that covers between alien-frequency district,, then do not trigger load balancing action between frequency if more approaching with duty ratio between the covering alien-frequency district, see step 108, otherwise, in the higher sub-district of load, select suitable UE, do the preparation of direct-cut operation between frequency, be step 105, promptly distribute adequate resources, set up Radio Link etc. for these UE with the base station at the lower Target cell of load;

Step 106, after RAN (Radio Access Network) side is finished all preparation, by RNC direct-cut operation (reshuffling) message between UE sends frequently, frequently between direct-cut operation message be one of following three kinds: physical channel reconfiguration message, transmission channel reconfiguration message, radio bearer reconfiguration message;

Step 109, direct-cut operation (reshuffling) was finished message between UE returned frequently, it is corresponding that this finishes between frequency in message and the step 106 direct-cut operation, for one of following three kinds: physical channel reshuffle finish message, transmission channel reshuffle finish message, radio bearer is reshuffled and is finished message.

Fig. 2 is the message flow of RNC and NodeB in processing procedure.Step 101 and step 102 in the corresponding diagram 1:

RNC sends public-measurement order (Common Measurement Initiation Request) to each Node B, and step 201 has measuring amount, reports mode, some important information such as filtration coefficient in the order; When Node B thinks that in inspection the ability of oneself can be competent at measurement, return public-measurement initial communication (Common MeasurementInitiation Response) to RNC, step 202, and begin to measure, when NodeB finds to reach report condition when measuring, Node B is when reaching report condition, send public-measurement report (Common MeasurementReport) to RNC, step 203, for the periodic report mode, just report one-shot measurement result, step 204 at set intervals to RNC.

Fig. 3 is a specific messages flow process relevant with UE in processing procedure.Step 105 in the corresponding diagram 1,106,107:

RNC is after finding the gap that reaches predetermined with the load that covers alien-frequency district, at the higher suitable UE of cell selecting of load, and in Target cell (i.e. the lower same covering alien-frequency district of load), prepare corresponding resource, send radio link reconfiguration to the NodeB of Target cell correspondence and prepare message (Radio Link Reconfiguration Prepare), see step 301, NodeB is after receiving this message, Node B also will be corresponding UE reservation of resource, and return radio link reconfiguration and be ready to message (Radio Link Reconfiguration Ready), see step 302, RNC is after receiving this message, definite time point that will switch, and to NodeB transmission radio link reconfiguration submission (RadioLink Reconfiguration Commit), see step 303, direct-cut operation (reshuffling) order between UE sends frequently immediately, see step 304, this order may be reshuffled or transmission channel is reshuffled or radio bearer reconfiguration message for physical channel, UE finish aerial synchronously after, direct-cut operation (reshuffling) is finished message between RNC returns frequently, see step 305, this message with frequently between the direct-cut operation order corresponding, may reshuffle for physical channel and finish or transmission channel is reshuffled and finished or radio bearer is reshuffled and finished message, enter normal communication process then.

In addition, take place for fear of too much frequent balanced action, in embodiment shown in Figure 4 two, on the basis of embodiment shown in Figure 1, increased step 109, promptly preferentially judge whether the load of sub-district is lower than a threshold value that sets in advance, if, think that then each all is in a lower level with the load that covers alien-frequency district, load balancing between not considering this moment frequently, can not produce big influence to system yet, can not carry out equilibrium action, like this can more effective reduction because the call drop that direct-cut operation causes between taking place frequently possible.

Claims

1, load balance control method between the frequency in a kind of broadband CDMA system is characterized in that, said method comprising the steps of:

(1) radio network controller regularly obtains reflection cell load condition information from Node B;

(2) radio network controller is according to the load of predefined load threshold parameter, sub-district actual measurement and with the load that covers alien-frequency district, and whether decision is necessary to carry out balanced action;

(3) if the equilibrium action to alien-frequency district is carried out in decision, then in this sub-district, select the part subscriber equipment, and send the order of direct-cut operation between frequency to these subscriber equipmenies;

(4) subscriber equipment of execution switching returns in alien-frequency district and finishes message.

2, load balance control method between the frequency in the broadband CDMA system according to claim 1 is characterized in that, described step (1) specifically may further comprise the steps:

(1.1) radio network controller sends at sub-district public-measurement control command to Node B, requires to measure to receive broadband power and/or emission carrier power value, and sets the condition that reports, and for the periodic report mode, needs to set the cycle that reports; For reporting events, need to set thresholding, the triggered time that reports;

(1.2) Node B is to the up reception broadband power of respective cell and/or emission carrier power value, during report condition in reaching the measurement control order that radio network controller sends, reports to radio network controller;

(1.3) radio network controller stores the result that Node B reports, and uses during for needs.

3, load balance control method between the frequency in the broadband CDMA system according to claim 1 and 2 is characterized in that, in the described step (2) decision whether be necessary to carry out balanced action one of can be in the following ways:

(2.1) be limited as in the main system at up direction, can only select the reception broadband power that adopts up direction to receive, as duty ratio reference between each sub-district, the reception broadband power that receives when the cell uplink direction is higher than it when covering respective doors limit value that alien-frequency district sets, and balanced action is carried out in decision;

(2.2) be limited as in the main system at down direction, can only select to adopt down direction emission carrier power value, as duty ratio reference between each sub-district, when cell downlink direction emission carrier power value was higher than its respective doors limit value that covers the alien-frequency district setting together, the equilibrium action was carried out in decision;

(2.3) in the system that the uplink and downlink direction need be taken all factors into consideration, the reception broadband power and the down direction emission carrier power value that can adopt up direction to receive simultaneously, as duty ratio reference between each sub-district, reception broadband power that receives when the cell uplink direction and down direction emission carrier power value are higher than it respectively when covering respective doors limit value that alien-frequency district sets, and balanced action is carried out in decision.

4, load balance control method between the frequency in the broadband CDMA system according to claim 3, it is characterized in that, can also set an Xiamen limit value, when the load of sub-district actual measurement during less than this Xiamen limit value, system does not carry out the equilibrium action, to avoid too much frequent balanced action.

5, load balance control method between the frequency in the broadband CDMA system according to claim 1, it is characterized in that, comprise in the command messages of the direct-cut operation in the described step (3): the scrambling code information of cell frequency information, sub-district and the resource information of being distributed.

6, load balance control method between the frequency in the broadband CDMA system according to claim 1 or 5 is characterized in that, selects the subscriber equipment of direct-cut operation one of can be in the following ways or combination in the described step (3):

(3.1) selection is not in the subscriber equipment of soft changing state;

(3.2) select QoS to require lower subscriber equipment;

(3.3) select the lower subscriber equipment of service rate.