CN1210901C

CN1210901C - Resource allocation method on switching for CDMa base station system

Info

Publication number: CN1210901C
Application number: CNB011057092A
Authority: CN
Inventors: 薛育红; 范雪峰; 刘金龙
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2001-03-22
Filing date: 2001-03-22
Publication date: 2005-07-13
Anticipated expiration: 2021-03-22
Also published as: CN1377151A

Abstract

The present invention discloses a resource allocation method when a CDMA base station system is switched, which comprises the procedures as following: firstly, judging whether an adjacent subzone with the same frequency in the same BTS and gaining the same frame offset can be found, if true, carrying out soft switch; secondly, judging whether the available frame bias of a channel unit is the same as the currently used frame bias, if true, carrying out the soft switch; if the condition of the soft switch can not be satisfied, adopting semi-soft switch. The present invention can avoid connection lost effectively, improve calling effect and utilize the system resources well.

Description

Resource allocation methods when cdma base station system switches

The present invention relates to cdma base station system, relate in particular to resource allocation methods when carrying out the minizone switching in the cdma base station system.

Because the CDMA mobile communcations system is at the cellular system that all is superior to other aspect power system capacity and the reduction radiation far away, so cdma system has all obtained application more and more widely all over the world.In cdma system, the switching of travelling carriage in cdma base station system is a very part and parcel, adopts different switching modes, directly has influence on success rate for switching and resource utilization.Need clear and definite switching mode during the switching of travelling carriage in cdma base station system, correspondingly distribute simultaneously various resources, present switching mode mainly comprises soft handover, More Soft Handoff and medium-soft are switched three kinds, carry out between two adjacent sectors of More Soft Handoff in same base station transceiver, only need redistribute Traffic Channel, and which Channel Elements in the Channel Elements of calling has been set up in definite use, during More Soft Handoff because need not distribute new Channel Elements, so handoff procedure is short, cause the possibility of call drop very low during switching, so when switching, at first judge and to carry out More Soft Handoff.Soft handover is meant the switching between the same carrier frequency of different districts, soft handover needs allocated channel unit and Traffic Channel, and the frame biasing is identical with the frame biasing of having set up calling originally, soft handoff is a big characteristic of cdma system, adopt soft handoff, conversation is also uninterrupted, even make the user also can keep talking state in fast moving always.It is a kind of mode of direct-cut operation that medium-soft is switched, be meant at same base station controller (BSC, Base Station Controller) switching between interior different districts, need to distribute new Traffic Channel and Channel Elements, the conversation that the medium-soft switching need be dismantled and original base station has been set up, foundation and the newly communication process of base station again, obviously the medium-soft switching is not the suitable switching mode of the desirable selection of user, cutting off rate and communication effect when this mode has directly influenced switching.In present practical application, when mobile phone finds that former base station pilot signal is very weak, when requiring to switch, what generally adopt is to choose at random switching mode, cause handover success rate very low, increase the possibility of call drop when switching, and many times can cause resource waste.Can't embody the no gap conversation advantage of cdma system.

The resource allocation methods when cdma base station system that purpose of the present invention proposes a kind ofly effectively to avoid call drop, improve communication effect and make full use of system resource switches, the low and inadequate shortcoming of system resource utilization of cutting off rate height, speech quality that the randomness of resource allocation is brought when switching to overcome existing cdma base station system.

For achieving the above object, resource allocation methods when the present invention proposes a kind of cdma base station system and switching is characterized in that, may further comprise the steps:

101 judge the adjacent area whether in this base station controller according to pilot offset, if in this base station controller, then continue this adjacent area, otherwise report can not switch, and changes 116;

102 judge whether the adjacent area has the carrier frequency of same frequency, if having the carrier frequency of same frequency, then continue, otherwise change 111;

103 judge that current frequency has or not idle business channel, if idle Traffic Channel is arranged under the current frequency, then continue, otherwise change 111;

104 find corresponding base band data subsystem;

105 according to the resource operating position, and judging whether can More Soft Handoff, if the conditions being possessed that carries out More Soft Handoff then changes 110, otherwise continues;

106 according to the frame biasing operating position that is write down, and obtains all available frame biasings;

107 judge whether the frame biasing that Channel Elements can be used is identical with the present frame biasing of using, if identical, then carries out soft handover, then continues, otherwise changes 111;

108 judge whether also to exist idle and available Channel Elements resource, if there is not available Channel Elements resource, then change 111; Otherwise continue;

109 according to the frame offset allocations Channel Elements resource of being distributed;

110 distribute idle Traffic Channel, if handover resource allocation is finished, change step 116 otherwise commentaries on classics step 101;

111 according to the load sharing principle, chooses the minimum carrier frequency of load from all carrier frequency successively, if also have available carrier frequency, then continue, otherwise report resource allocation failure changes 116;

112 select another carrier frequency, do not distribute the medium-soft of new vocoder unit to switch;

113 judge whether idle business channel is arranged under this carrier frequency, if there is not available idle business channel, then change 111; Otherwise continue;

114 judge Channel Elements can with every frame of frame biasing and selector vocoder of the Channel Elements that whether allows less than given maximum of every frame of frame biasing and selector vocoder difference of beginning the sampling time begin the poor of sampling time, if less than, then continue, otherwise the resource allocation failure changes 116;

115 judge that whether this sub-district also has idle Channel Elements resource, if having, changes 109, otherwise changes 111;

116 finish.

Adopt the method for the invention, can select best switching mode according to the condition that is possessed, under different conditions, select modes such as More Soft Handoff, soft handover and medium-soft switching respectively, thereby improved switch speed effectively, reduced and called out shared selector vocoder and Channel Elements, made full use of resource, enlarge the base station capacity, improved economic benefit.And increased the probalility of success of soft handover, reduce the cutting off rate of travelling carriage when switching.With respect to existing changing method, the many drawbacks that can avoid the randomness of switching mode to bring effectively make the handoff procedure maximizing efficiency become possibility.

The invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is a cdma base station system handover resource allocation flow chart of the present invention.

In flow chart shown in Figure 1, stipulated to allow at most on the channel board what identical frame biasings, the frame biasing of each Channel Elements is unfixing.Can the handover resource allocation strategy that propose according to the present invention be at first judged allow mobile phone do More Soft Handoff, because its reliability is the highest; Next judges whether the condition of soft handover satisfies; If the condition of soft handover can not satisfy, then select for use medium-soft to switch.With selector vocoder and the Channel Elements that reduces to take, and reduce cutting off rate.Because cdma system uses pilot offset to distinguish different base stations, so at first will judge that the adjacent area is whether in this base station controller BSC according to pilot offset, if this adjacent area is not in this base station controller BSC, then report can not be switched, otherwise judge whether the adjacent area has the carrier frequency of same frequency, if have identical carrier frequency, judge that current frequency has or not idle business channel, if idle Traffic Channel is arranged under the current frequency, find corresponding base band data subsystem (BDS Base band DigitalSubsystem), according to the resource operating position, judging whether can More Soft Handoff.If the conditions being possessed that carries out More Soft Handoff, Resources allocation, the condition of carrying out More Soft Handoff are to find frequency identical at same base station transceiver (BTS, basetransceiver station), and can get the abutting subdistrict of same number of frames biasing.Otherwise judge whether to carry out soft handover,, then carry out soft handover, Resources allocation if the frame that Channel Elements can be used biasing is identical with the frame biasing of using now.When soft handover and More Soft Handoff condition all do not satisfy, then attempting carrying out medium-soft switches, according to the load sharing principle, select the minimum carrier frequency of load, if this carrier frequency has idle business channel, and Channel Elements can with every frame of frame biasing and selector vocoder begin the sampling time difference less than set-point, then Resources allocation is carried out medium-soft and is switched.Distribute failure otherwise return.Thereby increased the probability of soft handover effectively, reduced the cutting off rate in the communication process, and reduced to greatest extent the taking of selector vocoder and Channel Elements made full use of resource, improved economic benefit.

Claims

Resource allocation methods when 1, a kind of cdma base station system switches is characterized in that, may further comprise the steps:

Step 1 (101) is judged the adjacent area whether in this base station controller according to pilot offset, if in this base station controller, continue this adjacent area, otherwise report can not switch, and changes step 16 (116);

Step 2 (102) judges whether the adjacent area has the carrier frequency of same frequency, if having the carrier frequency of same frequency, then continues, otherwise changes step 11 (111);

Step 3 (103) judges that current frequency has or not idle business channel, if idle Traffic Channel is arranged under the current frequency, then continues, otherwise changes step 11 (111);

Step 4 (104) finds corresponding base band data subsystem;

Step 5 (105) is according to the resource operating position, and judging whether can More Soft Handoff, if the conditions being possessed that carries out More Soft Handoff then changes step 10 (110), otherwise continues;

Step 6 (106) obtains all available frame biasings according to the frame biasing operating position that is write down;

Step 7 (107) judges whether to meet soft handoff condition, if meet, then carries out soft handover, continues, otherwise changes step 11 (111);

Step 8 (108) judges whether also to exist idle and available Channel Elements resource, if there is not available Channel Elements resource, then changes step 11 (111), otherwise continues;

Step 9 (109) is according to the frame offset allocations Channel Elements resource of being distributed;

Step 10 (110) is distributed idle Traffic Channel, and handover resource allocation is finished, and changes step 16 (116), otherwise changes step 1 (101);

Step 11 (111) is chosen the minimum carrier frequency of load successively according to the load sharing principle from all carrier frequency, if also have available carrier frequency, then continue, otherwise step 16 is changeed in report resource allocation failure;

Step 12 (112) is selected another carrier frequency, does not distribute the medium-soft of new vocoder unit to switch;

Step 13 (113) judges whether idle business channel is arranged under this carrier frequency, if there is not available idle business channel, then changes (111); If have, then continue;

Step 14 (114) judge Channel Elements can with every frame of frame biasing and selector vocoder of the Channel Elements that whether allows less than given maximum of every frame of frame biasing and selector vocoder difference of beginning the sampling time begin the poor of sampling time, if less than, then continue, otherwise step 16 (116) is changeed in the resource allocation failure;

Step 15 (115) judges whether this sub-district also has idle Channel Elements resource, if having, changes step 9 (109), otherwise changes step 11 (111);

Step 16 (116) finishes.
Resource allocation methods when 2, cdma base station system according to claim 1 switches, it is characterized in that the condition of the More Soft Handoff described in the step 5 (105) is can find frequency identical and can get the abutting subdistrict of same number of frames biasing at same base station transceiver.
Resource allocation methods when 3, cdma base station system according to claim 1 switches is characterized in that, the described soft handoff condition that carries out of step 7 (107) is that the frame biasing that Channel Elements can be used is setovered identical with the frame of current use.