Summary of the invention
The objective of the invention is to design the hand over control method in a kind of mobile communication system, can be according to different business quality (QoS) requirement, adopt the self adaptation Handoff Control strategy of different Handoff Control algorithms, make that the Handoff Control in the 3G (Third Generation) Moblie network is more effective.
The technical scheme that realizes the object of the invention is such: the hand over control method in a kind of mobile communication system, it is characterized in that, and may further comprise the steps:
A. network terminal judges whether user terminal applies for multiple business simultaneously, if enter step B after then selecting the highest business of priority as current application business according to the priority that sets in advance; Otherwise, enter step B;
B. according to the professional quality of service requirement of current application, selector is should the switch determining method of quality of service requirement, generate the candidate target cells tabulation according to measurement report from base station, user terminal to send up, and judge whether the candidate target cells that generates satisfies the switching condition of selected switch determining method, if satisfy, then enter step C; Otherwise, process ends;
C. according to the distance between the target cell base station of the switching condition that satisfies selected switch determining method in the tabulation of the candidate target cells of described user terminal and generation, and/or user terminal mobile trend, and/or the information on load of the Target cell of the described switching condition that satisfies selected switch determining method, the described Target cell that satisfies the switching condition of selected switch determining method is sorted, and select the high Target cell of priority to admit operation as the Target cell that switches.
Among the step B, described quality of service requirement comprises: time delay, signal quality;
Described according to the professional quality of service requirement of current application, selector should the method for the switch determining method of quality of service requirement be:
B1. network terminal judges whether described current business is the high business of demand on signal quality, if then enter step B2; Otherwise, enter step B3;
B2. judge whether described current business is the business of delay requirement less than predetermined threshold value, if then described current business is adopted based on the preferential switch determining method of adjudicating of signal quality; Otherwise, if delay requirement and demand on signal quality then adopt the switch determining method based on pilot signal strength and signal quality cascading judgement all less than the business of predetermined threshold value;
B3. judge whether described current business is the business of delay requirement less than predetermined threshold value, if then current business is adopted based on the preferential switch determining method of adjudicating of pilot signal strength; Otherwise, if delay requirement adopts the switch determining method of adjudicating based on relative pilot signal strength with the business that demand on signal quality all is not less than predetermined threshold value.
The hand over control method that is applied in the mobile communication system of the present invention relates to the coordination of network terminal and user terminal each side in the Handoff Control process.When hand over control method of the present invention is applied in the handoff procedure, be embodied in two aspects: be that network judges whether user terminal needs to switch on the one hand; Be select target sub-district how when judging that user terminal need switch on the other hand.Basic thought of the present invention is, at first select switch determining method according to the business and the quality requirement of user applies, the judgement of whether switching according to selected switch determining method is then selected best Target cell according to Target cell selection algorithm of the present invention at last.
The present invention is the hand over control method in a kind of mobile communication system that is applied to multi-stage service, different service quality requirement according to the user applies business (is QoS, comprise the error rate, time delay, professional priority level etc.) adopt the switch determining method of different mode decision schemes.Adopt in the process whether a kind of mode decision scheme judgement user need to switch in network selecting, when user terminal application the time, preferentially adjudicate, auxiliaryly simultaneously carry out comprehensive and optimize the switch determining method of judgement with information such as pilot signal strengths with adopting based on signal quality for the higher business of error rate quality requirements such as (BER); When user terminal application during, preferentially adjudicate, auxiliaryly simultaneously carry out comprehensive and the switch determining method judged (thresholding of concrete delay requirement by network system according to the network configuration and the professional concrete setting that can provide) is provided with information such as signal qualitys with adopting based on pilot signal strength for higher professional of delay requirement; In the user terminal application in the multiple business, preferentially select switch determining method according to higher priority business.The priority level here can be professional natural priority grade, also can be the priority level that mobile communications network sets up on their own.
The present invention is selecting according to other relevant information on the basis of candidate target cells, also can further select candidate target cells according to the pilot signal strength of user terminal measurement; According to the moving direction of distance between user terminal and base station and user terminal candidate target cells is tabulated again on this basis and sort again; With on the basis of sorting again for candidate target cells, utilize network measuring to the load condition of each Target cell carry out prioritization, the lighter Target cell of loading is set to higher priority.System can sort to neighbor cell according to the long-term average load information in sub-district, and the sub-district that long-term average load is less is provided with higher priority level in the Target cell tabulation.
What the present invention proposed is a kind of self adaptation switchover policy that can require to adopt different handoff decisions algorithms according to different QoS.The switch decision algorithm that adopts is the judgement that is used in combination pilot signal strength and signal quality, wherein the pilot signal strength judgement is the down-bound pilot frequency signal intensity that adopts user terminal measurement Serving cell and neighbor cell, and the error rate parameters directly related with signal quality such as (BER) of user terminal measurement Serving cell adopted in the signal quality judgement.The measurement of pilot signal strength can be accomplished very accurately and timely, thereby can be used as basic decision rule; The measurement of relevant quality, as the error rate (BER) and Block Error Rate (BLER) etc., its measure to filter and measuring period longer relatively, and direct reflected signal quality sometimes, thereby can be used as the auxiliary judgement criterion.This decision method that both combine can make performance of handoffs and function in the mobile communication system more effective.
The present invention proposes a kind of method of assessing definite Target cell in conjunction with distance and user terminal moving direction between user terminal and the base station, this method can be used separately also can determine that the criterion of Target cell is used in combination with other assessments, can guarantee effectively that UE is switched to nearest with it or the more and more nearer sub-district of distance with it as early as possible, reduces cutting off rate and does not increase switching times.
The inventive method is when select target sub-district from candidate cell, can be on the basis of other select target sub-district criterion, permission is inquired about the load condition of candidate cell, the Target cell that switches earlier of decision again after taking all factors into consideration avoids taking place the low phenomenon of handover success rate in the conventional method.
Embodiment
The present invention is a kind of hand over control method that is applied in the mobile communication system, to aspect the switch decision of user terminal, has considered the selection of the switch decision algorithm under the multi-stage service situation at mobile communications network.When the user terminal application during for higher professional of error rate quality requirements such as (BER), with adopt based on signal quality preferentially adjudicate, the auxiliary method for handover control that carries out the complex optimum judgement with information such as signal strength signal intensities simultaneously; When the user terminal application during for higher professional of delay requirement, will adopt based on signal strength signal intensity preferentially adjudicate, the auxiliary method for handover control that carries out the complex optimum judgement with signal quality information such as (as the error rates) simultaneously.In the user terminal application in the multiple business, will select the switch decision algorithm according to higher priority business.The present invention has made full use of the distance between travelling carriage and base station in the algorithm that Target cell is selected, the mobile trend of travelling carriage and the information such as load condition of network are optimized selection to Target cell.
The basic process that realizes the inventive method is: at first according to the service selection switch determining method of user applies, the judgement of whether switching according to selected switch determining method then, Target cell selection algorithm according to the present invention is at last selected corresponding Target cell.
Referring to Fig. 1, it is the main-process stream block diagram of hand over control method of the present invention, earlier carry out the selection of switch decision algorithm according to the business of user terminal application, from the preferential decision algorithm of pilot signal strength, relative pilot signal strength decision algorithm, the preferential decision algorithm of signal quality and signal quality pilot signal strength cascading judgement algorithm, select a kind of switch decision algorithm, the judgement of whether being switched by selected switch decision algorithm is then being judged when needing to switch the select target sub-district and is being switched.
Step 101, network terminal obtains the business information of user terminal (UE) application.In the present invention, network terminal can be different qos requirements according to the difference of user applies business, selects different switch decision strategies adaptively.Like this can so that the switching control function that has the business that different QoS requires in the 3-G (Generation Three mobile communication system) more flexibly, reliable and efficient, thereby improve the performance of handoffs of system greatly.In the business of 3-G (Generation Three mobile communication system) definition, the characteristic of different business mainly is reflected on the difference of qos requirement.The QoS index of reference of the present invention mainly comprises the error rate (BER) requirement, the priority level requirement of delay requirement and business etc.For the user who has applied for multiple business, should select corresponding switching criterion according to the TP top priority of every business need.The priority of miscellaneous service can be set by mobile communications network, also can arrange according to professional natural priority level own.
Step 102,103 if user terminal has been applied for multiple business simultaneously, and is provided with priority, then preferentially selects the highest professional execution in step 104 of priority, otherwise direct execution in step 104.
Step 104,105,106, carrying out the switch decision algorithm by criterion selects, concrete criterion is: pay the utmost attention to the switch decision algorithm (107) of employing based on the preferential judgement of pilot signal strength for delay requirement less than the business of a certain threshold value in switching, also can carry out the auxiliary judgement of signal quality simultaneously on this basis; For the business of error rate quality requirements such as (BER) less than a certain threshold value, in switching, pay the utmost attention to switch decision algorithm (109) based on the preferential judgement of signal quality (error rate etc.), also can carry out the auxiliary judgement of signal strength signal intensity simultaneously on this basis; All in switching, consider the switch decision algorithm (110) of employing for time delay and error rate quality requirements such as (BER) based on signal strength signal intensity and signal quality cascading judgement less than the business of a certain threshold value; The business that all is not less than a certain threshold value for time delay and error rate quality requirements such as (BER) considers to adopt the switch decision algorithm (108) of adjudicating based on relative pilot signal strength in switching, because this business is relatively low for qos requirement, so also can adopt other simple and effective switch decision algorithm.
Step 111,112,113, after choosing switch decision algorithm (107 or 108 or 109 or 110), network (RNC) is handled the measurement report that is reported by base station, user terminal (UE), generate the candidate target cells tabulation in view of the above, judge whether to satisfy the switching condition of selected algorithm (107 or 108 or 109 or 110), do not satisfy and then finish the switch decision program, the further selection algorithm of select target sub-district then when satisfying.
Step 114,115,116, the selection algorithm of elder generation select target sub-district, then by the selection algorithm select target sub-district of selecting, when not admitting, the current goal sub-district selects whether to attempt next Target cell (from the candidate cell tabulation), then finish this Handoff Control process when not attempting, then return execution in step 113,114 during trial, after being admitted, link with setting up by Signalling exchange between the Target cell of admitting by the current goal sub-district.
Below respectively in conjunction with the accompanying drawings 2 to accompanying drawing 5 explanation the present invention method of the switch decision algorithm that selection is adopted at different business (different quality requirements) how.Promptly embody by network and judge whether user terminal needs to switch.
Referring to Fig. 2, the switch decision algorithm (the preferential decision algorithm 107 of pilot signal strength) that adopts less than the business of a certain threshold value for delay requirement shown in the figure.Provide the business high among the figure, in switching, pay the utmost attention to the switch decision criterion of employing, carry out the auxiliary judgement of signal quality simultaneously on this basis based on the preferential judgement of signal strength signal intensity to delay requirement.
For the business of delay requirement less than a certain threshold value, in switch decision, trigger the switch decision algorithm according to the pilot signal strength criterion, the concrete steps of algorithm are as follows:
Step 201, travelling carriage are at first measured the pilot signal strength of Serving cell and neighbor cell, then measurement result are reported network, trigger the switch decision process, adjudicate.When the pilot signal strength that has a neighbor cell at least surpasses the pilot signal strength of Serving cell and the (pilot signal strength of neighbor cell-this district pilots signal strength signal intensity 〉=C1 during greater than a predefined threshold value C1, C1 is the relative threshold of pilot signal strength), execution in step 202, otherwise finish the switch decision process.
Step 202, network judges whether the reception pilot signal strength of Serving cell (this sub-district) is lower than level threshold value C2, if the pilot signal strength of Serving cell is higher than threshold value C2, then finish the switch decision process, wait for handover trigger next time, if the pilot signal strength of Serving cell is lower than threshold value C2, then continue execution in step 203;
Step 203,204,205, whether the pilot signal strength of judging Target cell is higher than threshold value C3, if the pilot signal strength of Target cell is not higher than threshold value C3, the channel adjustment operation is carried out in i.e. indication, if the pilot signal strength of Target cell is higher than threshold value C 3, whether the quality of then further judging uplink and downlink signals on this basis is lower than signal quality thresholding C4, channel adjustment is carried out in indication when being not less than, handover operation is carried out in indication when being lower than, C2 and C3 are the absolute thresholding of pilot signal strength, and C4 is the absolute thresholding of signal quality.
Above-mentioned steps also can only consider to adopt the switch decision criterion based on the signal strength signal intensity judgement in switching when implementing, promptly save step 204.In step 203, indication is switched when the pilot signal strength of judgement Target cell is higher than thresholding C3, indicating channel adjustment when the pilot signal strength of judgement Target cell is not higher than thresholding C3.
The principal character of the switch determining method of this optimization is that relative pilot signal strength decision algorithm is combined with absolute pilot signal strength decision algorithm, and the feasible result who judges more accurately and reliably.Reduce the deviation that the random fluctuation owing to measurement result produces.In the deterministic process of algorithm be the preferential criterion of judging, make system sensitive more, so be applicable to for the relatively more responsive business of delay requirement for user's judgement reaction with the signal strength signal intensity.
Referring to Fig. 3, the switch decision algorithm (the preferential decision algorithm 109 of signal quality) that adopts less than the business of a certain threshold value for quality requirement shown in the figure, to the demanding business of quality, in switching, pay the utmost attention to the switch decision criterion of employing, carry out the auxiliary judgement of signal strength signal intensity simultaneously on this basis based on the preferential judgement of signal quality.
Insensitive but to time delay to the business of error rate quality requirements such as (BER) less than a certain threshold value, adopt the priority signal quality to trigger switch decision, the algorithm of auxiliary signal intensity judgement, the concrete steps of algorithm are as follows:
Step 301, at first, the signal quality of network and user terminal measurement Serving cell, comprise the error rate (BER) or Block Error Rate (BLER) etc., then the signal quality result who measures is compared with predefined quality threshold A1 (the corresponding different threshold value of different quality signals), if signal quality measurement result is higher than threshold value A1 (A1 is the early warning thresholding), then finish this switch decision process, if signal quality measurement result is lower than thresholding A1, then execution in step 302, and threshold value A1 is the absolute thresholding of signal quality.
Step 302, further signal quality measurement result is compared with threshold value A2, if signal quality measurement result is lower than threshold value A2, network is promptly indicated and is carried out handover operation (step 304), if signal quality measurement result is higher than threshold value A2, then further execution in step 303, threshold value A2 is the absolute thresholding of signal quality, A2>A1 on the numerical value, so A1 constitutes the early warning thresholding.
Step 303,304,305, judge that the pilot signal strength have a neighbor cell at least surpasses the pilot signal strength of Serving cell and during greater than a predefined threshold value A3 (during at least one neighbor cell pilot signal strength-this district pilots signal strength signal intensity 〉=A3), then network is indicated and is carried out handover operation (step 304), otherwise, network indication carrying out channel adjustment operation (step 305); Thresholding A3 is the relative threshold of pilot signal strength.
The principal character of the switch determining method of this optimization is that the switch decision algorithm with signal quality combines with the pilot signal strength decision algorithm, and wherein signal quality has adopted double threshold (A1, the A2) decision method that early warning thresholding (A1) is set.The result who make to judge like this requires on the basis more accurately and reliably at the BER of business.Reduce because the switching call drop that the factors such as measurement time-delay of the random fluctuation deviation of measurement result and error rate quality requirements such as (BER) parameter produce.So this algorithm is applicable to for the relatively more responsive business of error rate quality requirements such as (BER).Also can only adopt during enforcement the decision method (when not comprising step 302) that a signal quality thresholding (A1) carries out once absolute threshold judgement is set; Also can adopt the switch decision that only carries out signal quality, promptly not comprise step 303.
Referring to Fig. 4, the switch decision algorithm (signal quality pilot frequency intensity cascading judgement algorithm 110) that all adopts for delay requirement and error rate quality requirements such as (BER) shown in the figure less than the business of a certain threshold value, to quality and all demanding business of time-delay, in switching, consider to adopt switch decision algorithm based on signal strength signal intensity and signal quality cascading judgement.
All less than the business of a certain threshold value, adopt the handoff algorithms of pilot signal strength and signal quality cascading judgement to carry out switch decision for delay requirement and error rate quality requirements such as (BER), the concrete steps of algorithm are as follows:
Step 401,402, at first, the pilot signal strength of user terminal measurement Serving cell and neighbor cell, simultaneously, the signal quality of network and user terminal measurement Serving cell (error rate BER, block error rate BLER etc.); Judge then, if the pilot signal strength that has a neighbor cell at least is above the pilot signal strength of Serving cell and greater than predefined threshold value B 1 (at least one neighbor cell pilot signal strength-this district pilots signal strength signal intensity 〉=B1, B1 also claims the surplus thresholding, be relative threshold), then continue execution in step 403, if do not satisfy this condition then finish this switch decision; If the signal quality of Serving cell (error rate BER, block error rate BLER etc.) is lower than threshold value B 3, then continue execution in step 404, if do not satisfy this condition then finish this switch decision;
Step 403,405,406, when at least one neighbor cell pilot signal strength-this district pilots signal strength signal intensity 〉=B1, continue to judge that whether its (also claiming hysteresis margin) be greater than relative level threshold value B 2 (at least one neighbor cell pilot signal strength-this district pilots signal strength signal intensity 〉=B2, B2 is a relative threshold), if this hysteresis margin is greater than relative level thresholding B2, then network is indicated and is carried out handover operation, otherwise, network indication carrying out channel adjustment operation;
Step 404,406,407 when the signal quality (error rate BER, block error rate BLER etc.) of the Serving cell of measuring when being lower than threshold value B 3, continues to judge whether it is lower than signal quality threshold value B 4; If signal quality measurement result also is lower than thresholding B4, then network is indicated and is carried out handover operation, otherwise, network indication carrying out channel adjustment operation.
Thresholding B1, B3 early warning thresholding for being provided with, thresholding B1 and B2 are the relative thresholds of pilot signal strength, thresholding B3 and B4 are the absolute thresholdings of signal quality, B2>B1 on the numerical value, B3>B4.
The principal character of the switch determining method of this optimization is that the switch decision algorithm with signal quality combines with the pilot signal strength decision algorithm, wherein signal quality and pilot signal strength have all adopted double threshold (B1 and B2, B3 and the B4) decision method of early warning (B1, B3) thresholding.Make that like this result who judges had both guaranteed professional BER or BLER requirement, also guaranteed professional delay requirement, make switch decision more accurately and reliably, reduced because the random fluctuation deviation of measurement result and BER or BLER measure the switching call drop of factor generations such as time-delay.So being applicable to for delay requirement and BER, this algorithm requires all to compare responsive business.
Also can only adopt during enforcement the decision method (when not comprising step 403) that a signal strength threshold (B1) is carried out a relative threshold judgement is set, only adopt and a signal quality thresholding (B3) is set carries out the once decision method (when not comprising step 404) of absolute threshold judgement, this moment is after execution of step 401,402, be judged as NO and then carry out end step, be judged as YES and then carry out the indication switching.The effect of obvious this processing was not as 403,404 o'clock in steps.
Referring to Fig. 5, all be not less than the switch decision algorithm (decision algorithm 108 of relative pilot signal strength) of the business employing of a certain threshold value shown in the figure for delay requirement and error rate quality requirements such as (BER), quality and time-delay are all required insensitive business, in switching, consider to adopt switch decision criterion based on the signal strength signal intensity judgement.
All be not less than the business of a certain threshold value for delay requirement and error rate quality requirements such as (BER), because this business is relatively low for qos requirement, so also can adopt simple and effective switch decision criterion.For this professional switch decision algorithm that adopts pilot signal strength to trigger switch decision, the concrete steps of algorithm are as follows in the present invention:
Step 501, travelling carriage are at first measured the pilot signal strength of Serving cell and neighbor cell, then measurement result are reported network, trigger the switch decision process, adjudicate.When the pilot signal strength that has a neighbor cell at least surpasses the pilot signal strength of Serving cell and the (pilot signal strength of at least one neighbor cell-this district pilots signal strength signal intensity 〉=C1 during greater than a predefined threshold value C1, C1 is the relative threshold of pilot signal strength), execution in step 502, otherwise finish the switch decision process.
Step 502, network judges whether the reception pilot signal strength of Serving cell (this sub-district) is lower than level threshold value C2, if the pilot signal strength of Serving cell is higher than threshold value C2, then finish the switch decision process, wait for handover trigger next time, if the pilot signal strength of Serving cell is lower than threshold value C2, then continue execution in step 503;
Step 503,504,505, judge whether to have at least the pilot signal strength of a neighbor cell to be higher than threshold value C3, if have at least the pilot signal strength of a neighbor cell to be higher than threshold value C3, then handover operation is carried out in indication, if the pilot signal strength of neighbor cell is lower than threshold value C3, then the channel adjustment operation is carried out in indication.
C2 and C3 are the absolute thresholding of pilot signal strength.
Also can only adopt during enforcement a signal strength threshold (C1) is set carries out the judgement of relative threshold, carry out the decision method (when not comprising step 502) of an absolute threshold judgement of pilot signal strength then.
When network is judged user terminal and need be switched according to selected algorithm, carry out the operation of select target sub-district.Further specify the system of selection of Target cell of the present invention below in conjunction with accompanying drawing 6.
Referring to Fig. 6, mainly utilize the distance between user terminal and the target cell base station in the present invention, the information on load of user terminal mobile trend and Target cell comprehensively carries out the selection of Target cell, and the algorithm of the criterion that is adopted (distance, direction and load) can use separately and also can be used in combination or be used in combination with the criterion of other assessment objective sub-district.Utilize earlier between travelling carriage and the base station distance and the travelling carriage moving direction of present embodiment come the assessment objective sub-district, utilize the candidate cell load condition to come the selected objective target sub-district again, can guarantee effectively that user terminal switches to sub-district nearest with it or that distance is more and more nearer as far as possible effectively, reduces and switches cutting off rate and switching times.
Concrete steps are as follows:
Step 601, it (is the technology that tradition was used during present mobile communication system cell switched that the measurement report that network reports by process user terminal and base station can generate the candidate target cells tabulation, repeat no more), thus be met the candidate target cells of switch decision condition.
Step 602, according to the pilot signal strength of candidate target cells to candidate cell tabulation carry out first time and sort.
Step 603, according to the user terminal location technology that various mobile communication system provided user terminal is positioned processing, the distance (TA) from locating information between acquisition user terminal and candidate cell base station and the destination of user terminal arrive information (DOA, azimuth);
Step 604 is carried out the ordering second time according to corresponding range information to candidate cell, will be set to higher priority level with the candidate cell (the TA value is less) of user terminal close together.
Step 605, step 606, from locating information, obtain the relative motion tendency information of user terminal, concrete operations can be with the TA of this measurement, the numerical value of DOA and preceding one-shot measurement compares, estimate the direction of motion of user terminal, movement tendency, according to corresponding movement tendency information candidate target cells is sorted for the third time again, and the more and more nearer candidate target cells of the distance between the user terminal is set to higher priority level (system can the recording user terminal and the relative distance and the azimuth information of candidate cell, relative distance reduce faster candidate cell is set to higher priority level).
Handover candidate cells tabulation after the cell list of three minor sorts can be used as renewal if this moment, judgement was switched, is that Target cell is admitted control with regard to the optional the highest sub-district of priority of selecting.Can after step 602,604,606, promptly carry out the selection of fancy grade Target cell respectively in the above-mentioned steps implementation.
The present invention proposes can to allow the load condition of candidate cell is inquired about on the basis of other select target sub-district criterions when the Target cell of selecting at first to switch from candidate target cells, determines the Target cell that at first request is admitted after taking all factors into consideration again.Promptly utilize the candidate cell load condition to come the selected objective target sub-district further.Concrete steps are:
Step 607 obtains the information on load of candidate cell.According to various performance accounting methods in the mobile communication system, calculate for the cell load in the mobile communication system.These performance index had both comprised the network operation situation index of long period statistics, also comprised the network operation situation index that system is calculated in real time.
Step 608 if system can provide the sub-district average load information of long period statistics, is then carried out the 4th minor sort according to corresponding average load information to neighbor cell list, and the less sub-district of average load is set to higher priority level.(these information comprise total emission power if system can provide real-time cell load information, interference volume and telephone traffic etc.), then the corresponding information on load in real time of basis carries out the 4th minor sort to the candidate target cells of switch decision, and the less candidate target cells of loading is set to higher priority level.
Step 609, selecting the highest sub-district of priority from tabulation is Target cell, switches.
Utilize this method can reduce the measurement hunting zone of user terminal effectively to neighbor cell.And when the switch decision condition is satisfied in a plurality of sub-districts, can communicate so that user terminal is linked into optimal sub-district.
Be example with the TD-SCDMA system below, illustrate that Handoff Control algorithm of the present invention is in concrete Application in Communication Systems.Listed the main business of in 3-G (Generation Three mobile communication system), using among Fig. 7, according to multi-stage service handoff algorithms based on qos requirement, to adopt different switchover policy to different service conditions, the adaptive scheduling process of its algorithm is finished by the corresponding radio resource administration module.
The concrete hand-off process scheme of the main business of using in the 3-G (Generation Three mobile communication system) is as follows:
For conversation class voice and video (Conversation voice and video), and speech message business such as (Voice messaging) can adopt the switch decision criterion (algorithm 107) that adopts for the higher business of delay requirement, can guarantee professional desired delay requirement (delay requirement be respectively less than less than 1 second with near 1 second) so effectively.
For file transfer (FTP), still image (still image, paging) and Email arrive to confirm that (the E-mail arrival notification) business of etc.ing can adopt the switch decision criterion (algorithm 109) of the business employing of having relatively high expectations for BER, can guarantee professional desired quality of service (delay requirement is respectively less than 10 seconds with greater than 10 seconds) so effectively.
For telnet interactive class recreation (Telnet interactive games), ecommerce (E-commerce), web page browsing (WWW browsing) and stream class Voice ﹠ Video (Streaming audioand video) business of etc.ing can adopt the switch decision criterion (algorithm 110) for all higher business employing of delay requirement and BER requirement, can guarantee effectively so professional desired quality of service and delay requirement (delay requirement be respectively less than less than 1 second, near 1 second with less than 10 seconds).
For business such as facsimile services (Fax), because it is lower for the priority ratio of various qos requirements, and mechanism such as feedback re-transmission etc. is arranged at high level, so can adopt the switch decision criterion (algorithm 108) that requires all not high business to adopt for delay requirement and BER, also can adopt the process that is similar to the sub-district gravity treatment to switch, when these two business of user applies and other professional mixed service, switch decision is as the criterion with other professional court verdict.
When the above-mentioned multi-stage service of user applies, switchover policy will mainly be as the criterion with the higher relatively business of priority.When switching judging, will mainly judge the trigger condition of the switching of the business that priority is high.Since the target of each Virtual network operator with provide professional different, so may need the priority of switching criterion is carried out artificial adjustment.
In the TD-SCDMA system, owing to adopted new technologies such as smart antenna and uplink synchronous, so can calculate the distance between UE and the base station relatively accurately, thereby make utilization distance of the present invention and prediction moving direction trend come the method for selected objective target sub-district more practical, therefore, not increasing under the situation of overhead, improved the performance of handoffs of system greatly.
Can adopt dual mode that the sub-district in the candidate cell tabulation is assessed, finally select the Target cell of switching:
First kind of mode carried out prioritization according to user terminal and the TA deviation between each candidate cell that user terminal measurement obtains to the sub-district in the candidate cell tabulation, and the less neighbor cell of TA deviation is set to higher priority.
The second way, user terminal that obtains according to user terminal measurement and the TA deviation between each candidate cell and judge that the trend of user terminal motion moves closer to this candidate cell or, preferentially become the condition of switching target small area as differentiating this sub-district with moving closer to this candidate cell away from this candidate cell for the measurement comparative result of smart antenna DOA.
The method that requires to select the switch decision algorithm according to multi-stage service of the present invention, according to the moving direction of distance between travelling carriage and base station and travelling carriage and method of selecting target cell, according to the method for cell load detected status optimized choice Target cell, can be applicable in the network equipment of mobile radio system and in the subscriber terminal equipment.