Multimedia broadcast multicast service scheduling method and system
Technical field
The present invention relates to the communications field, relate more specifically to a kind of multimedia broadcast multicast service scheduling method and system.
Background technology
Multimedia broadcast/group broadcast service (Multimedia Broadcast/Multicast Service is called for short MBMS) is a kind of shared network resource, transmits the technology of data to a plurality of targets from a data source.In order to effectively utilize mobile network resource, the 3rd generation partner project (Third Generation Partnership Project, abbreviation 3GPP) the MBMS business has been proposed in R6, promptly in the mobile network, provide a data source to send the point-to-multipoint service of data to a plurality of users, share raising utilization rate of network resource (especially Bao Gui air interface resource) to realize Internet resources.MBMS can not only realize the classes of messages multicast and the broadcasting of plain text low rate, and can realize the multicast and the broadcasting of high-speed multimedia business, multiple rich video, audio frequency and multimedia service are provided, this has complied with the trend of following mobile data development undoubtedly, for the development of mobile communication provides better professional prospect.
The structural model figure of MBMS operation system as shown in Figure 1.Broadcast multicast service center (Broadcast/Multicast Service Center, be called for short BM-SC) be newly-increased mobile network functional entity, it is content provider's a inlet, be used for authorizing and initiating the MBMS bearer service at mobile network, and plan transmits the MBMS content to schedule.
To existing WCDMA Packet Based Network functional entity: gateway GPRS supporting node (GGSN) (General Packet Radio Service Gateway Support Node, abbreviation GGSN), service universal grouping wireless business supporting node (Serving General PacketRadio Service Support Node, abbreviation SGSN), wireless access network (Radio AccessNet, be called for short RAN) and subscriber equipment (User Equipment, be called for short UE), also need to increase MBMS correlation function and process.
MBMS has introduced three kinds of new logic channels in RAN: the MBMS point is to multiple spot control channel (MBMS point-to-multipoint Control Channel, abbreviation MCCH), MBMS point-to-multipoint service channel (MBMS point-to-multipoint TrafficChannel, abbreviation MTCH), the MBMS point is to multiple spot scheduling channel (MBMSpoint-to-multipoint Scheduling Channel is called for short MSCH).Three kinds of newly-increased logic channels all are mapped to forward access channel (Forward Access Channel, be called for short FACH) on, FACH is mapped to again on the auxilliary public physical control channel (SecondaryCommon Control Physical Channel is called for short S-CCPCH).Radio network controller (Radio Network Controller is called for short RNC) uses MCCH to send the MBMS control information to UE; RNC uses MTCH to send the MBMS business datum to UE; RNC uses MSCH to send the schedule information of MBMS business to UE.
Professional stream class and the two kinds of types of service of background classes only supported of MBMS, wherein stream class service is suitable for the MBMS delivery of user traffic such as stream is professional most, it is continuous relatively to be characterized in that data send, relatively more responsive to propagation delay time, and background business is suitable for the MBMS delivery of user traffic such as message or download most, it is discontinuous to be characterized in that data send, less demanding to propagation delay time, promptly may not have data to send in long-time.Send discontinuous MBMS business for data, do not have business datum probably for a long time on the corresponding MTCH,, can increase the power consumption of UE like this, shorten the stand-by time of UE if do not notify UE then UE need monitor this MTCH all the time receives the MBMS business.3GPP has introduced the next schedule information that sends the MBMS business to UE of MSCH channel for this reason, promptly go up one or more MBMS business of carrying for a S-CCPCH, RNC need not send business datum at each Transmission Time Interval (Transmission Timing Interval is called for short TTI) on the MTCH of correspondence.If certain MBMS professional chief time does not have data to send to RNC or data volume is very little, then RNC can make a strategic decision and not send this business in current dispatching cycle even in ensuing several dispatching cycles.RNC uses MSCH will determine that good scheduling rule sends to UE in the starting point of each dispatching cycle, after UE reads the schedule information of MBMS business from MSCH, go to monitor in the time period of this dispatching cycle of appointment and want the professional corresponding MTCH of the MBMS that receives, then needn't monitor in the non-transmitting time section that receives business, thereby reach purpose of power saving.
MBMS service dispatching information delivery time need satisfy condition: (SFN-(SCTO div10ms)) mod MSCH_REP=MSCH_OFF, SFN (Cell SystemFrame Number wherein, Cell System Frame Number) is Cell System Frame Number, SCTO (SoftCombining Timing Offset, the soft merging time migration of MBMS) is the time migration that is used for the soft merging of MBMS.The configuration information of MSCH mainly comprises following 2 parameters:
In the MBMS service dispatching cycle (MSCH_REP), its span is [32,64,128,256,512,1024], and unit is the duration of a radio frames, i.e. 10ms;
Initial moment skew MBMS dispatching cycle (MSCH_OFF), the delivery time of MSCH on the different S-CCPCH in the sub-district that is used to stagger, span is [0.. (MSCH_REP-1)], unit is the duration of a radio frames, i.e. 10ms.
Defined the upward scheduling slot of each MBMS business of this S-CCPCH in the MBMS service dispatching information, comprised initial delivery time and sending duration, 2 parameter-definitions that relate to are as follows:
The initial delivery time (Start) of MBMS service dispatching period, value are that span is [0..1020] with reference to the time difference of that TTI of MBMS service dispatching information transmission; Step-length is 4; Unit is the duration of a radio frames, i.e. 10ms;
The sending duration of MBMS service dispatching period (Duration), its span are [4..1024]; Step-length is 4; Unit is the duration of a radio frames, i.e. 10ms.
Detailed scheduling setting is referring to the example of Fig. 2: 2 S-CCPCH that carry MTCH are arranged in certain sub-district, the SCTO=0 that it is corresponding, 4 FACH transmission channel FACH1, FACH2, FACH3, FACH4 have wherein been carried on the S-CCPCH1, wherein FACH1 carries the MSCH logic channel, FACH2, FACH3, FACH4 carry MBMS professional A, B, the MTCH logic channel MTCH a of C, MTCH b, MTCH c respectively, carried some FACH transmission channels on the S-CCPCH2, a FACH wherein is used to carry the MSCH logic channel.Have 3 UE receiving different MBMS business respectively in the sub-district, UE1 receives professional A, and UE2 receives professional B, and UE3 receives professional C.The TTI that supposes all FACH all is 40ms, MBMS MSCH_REP=32 dispatching cycle.
Step 1, in this dispatching cycle, RNC is provided with the MSCH_REP1=32 of S-CCPCH1 correspondence, MSCH_OFF1=0, the MSCH_REP2=32 of S-CCPCH2 correspondence is set, MSCH_OFF2=1, and it is included in the MSCH configuration information sends to UE all in the sub-district by MCCH.Like this, the starting point of each dispatching cycle of S-CCPCH1 and S-CCPCH2 1 radio frames that all staggered, current dispatching cycle corresponding district SFN is respectively 3200 and 3204.RNC goes up the transmission needs of professional A, B, C according to S-CCPCH1, the service dispatching information that be set the dispatching cycle of S-CCPCH1 is: professional A distributes 2 transmit time segments, the Start=4 of transmit time segments 1, Duration=4, the Start=20 of transmit time segments 2, Duration=4; Professional B distributes 1 transmit time segments, corresponding Start=8, Duration=8; Professional C does not distribute transmit time segments, i.e. do not send the data of professional C in this dispatching cycle, and RNC sends to UE all in the sub-district in the starting point of this dispatching cycle with service dispatching information; Equally, RNC goes up the service dispatching information that professional transmission needs are provided with S-CCPCH2 according to S-CCPCH2, then the dispatching cycle of S-CCPCH2 starting point send to all UE in sub-district, the setting of schedule information repeats no more in detail; RNC sends to all UE in the sub-district in the starting point of this dispatching cycle with the MBMS schedule information.
Step 2, UE1, UE2, UE3 get access to the MSCH_REP and the MSCH_OFF of S-CCPCH1 and the last MSCH correspondence of S-CCPCH2 from the MSCH configuration information that MCCH receives, mod MSCH_REP=MSCH_OFF calculates the initial moment of each dispatching cycle according to formula (SFN-(SCTO div 10ms)), then, UE1 begins to read the S-CCPCH1 channel in S-CCPCH1 the 5th and the 21st radio frames that starting point begins dispatching cycle and obtains business datum on the MTCH a, read at every turn and continue 1 TTI, i.e. 4 radio frames, other times are not read the S-CCPCH1 channel; UE2 begins to read the S-CCPCH1 channel in S-CCPCH1 the 9th radio frames that starting point begins dispatching cycle and obtains business datum on the MTCH b, continues 2 TTI, i.e. 8 radio frames, and other times are not read the S-CCPCH1 channel; UE3 does not read the S-CCPCH1 channel in the whole dispatching cycle of S-CCPCH1.
According to agreement, data are carried out segmentation with the data of a TTI when the actual transmission of physical layer, send in each radio frames that this TTI comprises then, promptly no matter send what of data among TTI, all need to be segmented in each radio frames that a TTI comprises and send.The TTI of FACH is 20ms in this example of hypothesis now, then send the professional A of data for needs, each transmit time segments only need continue 1 TTI, then the Duration of each transmit time segments only needs 2 radio frames, but the step-length according to existing protocol Duration value is 4 radio frames,, can not be arranged to 2 radio frames, UE1 must continuous 4 radio frames reads the S-CCPCH channel and obtains business datum on the MTCH a like this, makes UE increase by 1 times at the power consumption of this scheduling slot.The TTI that supposes FACH in the above-mentioned example again is 80ms, then the data of a TTI are included in and send in 8 corresponding radio frames, therefore the step-length of Duration value can not be 4 radio frames, can only be 8 radio frames, otherwise UE can only receive the data of preceding 4 radio frames in this TTI, and it is imperfect and abandon to cause receiving data.
In addition, at the MBMS business, the span of the TTI of agreement regulation MTCH is [20ms, 40ms, 80ms], but the TTI of MSCH is not had clear and definite regulation, so the span of its TTI can be [10ms, 20ms, 40ms, 80ms] in theory.The TTI=40ms of MSCH in the example of Fig. 2, according to agreement MSCH_OFF span: [0.. (MSCH_REP-1)], step-length: 1, therefore get MSCH_OFF=1, like this, 1 radio frames though MSCH starting point dispatching cycle on S-CCPCH1 and the S-CCPCH2 has staggered is because the TTI of MSCH is 4 radio frames, the MSCH of S-CCPCH1 and S-CCPCH2 goes up when reality sends the MBMS schedule information still has the delivery time of 3 radio frames overlapping, does not stagger fully.From the analysis of front as can be seen the existing protocol being provided with of MBMS service dispatching have following problem:
1, the TTI of MSCH is not considered in the setting of MSCH_OFF;
2, the TTI of MTCH is not considered in the setting of Start;
3, the TTI of MTCH is not considered in the setting of Duration;
Above problem can cause the transmission of MSCH schedule information not stagger fully, and the UE power saving effect is insufficient, even because of receiving the imperfect error in data that causes of data.
Summary of the invention
One or more problems in view of the above the invention provides a kind of multimedia broadcast multicast service scheduling method and system.
Multimedia broadcast multicast service scheduling method according to the present invention may further comprise the steps: S302, radio network controller is provided with the MSCH configuration information according to the Transmission Time Interval (TTI) of MSCH, Transmission Time Interval according to MTCH is provided with the MBMS service dispatching information, by the MCCH channel MSCH configuration information is sent to subscriber equipmenies all in the sub-district, by the MSCH channel MBMS service dispatching information is sent to all subscriber equipmenies in the sub-district in initial moment of dispatching cycle; S304, subscriber equipment is resolved after receiving the MSCH configuration information, read MBMS service dispatching information on the MSCH channel according to the MSCH configuration information after resolving in the starting point of dispatching cycle, and the MBMS service dispatching information resolved, read data on the MTCH channel according to the service dispatching information after resolving.
Wherein, in step S302, radio network controller is provided with MBMS initial moment skew dispatching cycle (MSCH_OFF) of current MSCH channel according to the Transmission Time Interval (TTI) of other MSCH in the current area, dispatching cycle in the initial moment of current MSCH channel was staggered with the dispatching cycle of other MSCH channels in the initial moment, and the radio frames number that staggers is enough to allow other MSCH channels send the MBMS service dispatching information.
Wherein, in step S302, radio network controller is provided with the initial delivery time (START) of MTCH scheduling slot according to the Transmission Time Interval of current MTCH, makes the initial delivery time of each scheduling slot of MTCH corresponding to initial moment of the Transmission Time Interval of MTCH.
Wherein, in step S302, radio network controller is provided with the sending duration (DURATION) of MBMS service dispatching period according to the Transmission Time Interval of current MTCH, and the sending duration of MBMS service dispatching period is the integral multiple of the Transmission Time Interval of current MTCH.
Wherein, in step S302, radio network controller also is provided with the MBMS service dispatching cycle (MSCH_REP).
Wherein, step S304 comprises: S3042, subscriber equipment obtain the initial moment of MBMS service dispatching cycle and MBMS dispatching cycle in initial moment calculations of offset each dispatching cycle from MCCH; S3044, subscriber equipment obtained the MBMS service dispatching information and reads data on the MTCH channel according to the MBMS service dispatching information from the MSCH channel according to initial moment of dispatching cycle.
Comprise according to multimedia broadcast multicast service scheduling of the present invention system: the service dispatching device, be positioned at the radio network controller side, be used for the MSCH configuration information being set according to the Transmission Time Interval of MSCH, Transmission Time Interval according to MTCH is provided with the MBMS service dispatching information, by MCCH the MSCH configuration information is sent to subscriber equipmenies all in the sub-district, and by the MSCH channel MBMS service dispatching information is sent to all subscriber equipmenies in the sub-district in initial moment of dispatching cycle; The business information deriving means, be positioned at user equipment side, being used for that subscriber equipment is received the MSCH configuration information resolves, and read MBMS service dispatching information on the MSCH channel in the starting point of dispatching cycle according to the MSCH configuration information after resolving, and the MBMS service dispatching information that is used for subscriber equipment is read resolves, and reads data on the MTCH channel according to the service dispatching information after resolving.
Wherein, the service dispatching device is provided with MBMS initial moment skew dispatching cycle (MSCH_OFF) of current MSCH channel according to the Transmission Time Interval (TTI) of other MSCH in the current area, dispatching cycle in the initial moment of current MSCH was staggered with the dispatching cycle of other MSCH channels in the initial moment, and the radio frames number that staggers is enough to allow other MSCH channels send the MBMS service dispatching information.
Wherein, the service dispatching device is provided with the initial delivery time (START) of MTCH scheduling slot according to the Transmission Time Interval of current MTCH, makes the initial delivery time of each scheduling slot of MTCH channel corresponding to initial moment of the Transmission Time Interval of MTCH.
Wherein, the service dispatching device is provided with the sending duration (DURATION) of MBMS service dispatching period according to the Transmission Time Interval of current MTCH channel, and the sending duration of MBMS service dispatching period is the integral multiple of the Transmission Time Interval of current MTCH.
Wherein, the service dispatching device also is provided with the MBMS service dispatching cycle (MSCH_REP).
The power consumption of UE can be farthest saved in the application of the invention, guarantees that UE intactly receives business datum, can also guarantee that the transmission of MBMS service dispatching information on the different MS CH channel is farthest staggered.
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:
Fig. 1 is the structural model figure of existing MBMS operation system;
Fig. 2 is the MCCH of existing protocol and the schematic flow sheet that MICH sets up;
Fig. 3 is the flow chart according to the multimedia broadcast multicast service scheduling method of the embodiment of the invention;
Fig. 4 is the schematic diagram of MBMS business scheduling method according to another embodiment of the present invention; And
Fig. 5 is the block diagram according to the multimedia broadcast multicast service scheduling system of the embodiment of the invention.
Embodiment
The present invention relates generally to the dispatching method and the system of MBMS business in Wideband Code Division Multiple Access (WCDMA) (Wideband Code DivisionMultiple Access the is called for short WCDMA) mobile communication system.Below with reference to accompanying drawing, describe the specific embodiment of the present invention in detail.
With reference to figure 3, the multimedia broadcast multicast service scheduling method according to the embodiment of the invention is described.As shown in Figure 3, this multimedia broadcast multicast service scheduling method may further comprise the steps: S302, radio network controller is provided with the MSCH configuration information according to the Transmission Time Interval of MSCH, Transmission Time Interval according to MTCH is provided with the MBMS service dispatching information, by MCCH the MSCH configuration information is sent to subscriber equipmenies all in the sub-district, and by the MSCH channel MBMS service dispatching information is sent to all subscriber equipmenies in the sub-district in initial moment of dispatching cycle; S304, subscriber equipment is resolved after receiving the MSCH configuration information, and read MBMS service dispatching information on the MSCH channel in the starting point of dispatching cycle according to the MSCH configuration information after resolving, and the MBMS service dispatching information resolved, read data on the MTCH channel according to the service dispatching information after resolving.
Wherein, in step S302, radio network controller is provided with MBMS initial moment skew dispatching cycle (MSCH_OFF) of current MSCH channel according to the Transmission Time Interval (TTI) of other MSCH channels in the current area, dispatching cycle in the initial moment of current MSCH was staggered with the dispatching cycle of other MSCH channels in the initial moment, and the radio frames number that staggers is enough to allow other MSCH send the MBMS service dispatching information.
Wherein, in step S302, radio network controller is provided with the initial delivery time (START) of MTCH scheduling slot according to the Transmission Time Interval of current MTCH channel, makes the initial delivery time of each scheduling slot of MTCH channel corresponding to initial moment of the Transmission Time Interval of MTCH.
Wherein, in step S302, radio network controller is provided with the sending duration (DURATION) of MBMS service dispatching period according to the Transmission Time Interval of current MTCH, and the sending duration of MBMS service dispatching period is the integral multiple of the Transmission Time Interval of current MTCH.
Wherein, in step S302, radio network controller also is provided with the MBMS service dispatching cycle (MSCH_REP).
Wherein, step S304 comprises: S3042, subscriber equipment obtain the initial moment of MBMS service dispatching cycle and MBMS dispatching cycle in initial moment calculations of offset each dispatching cycle from the MCCH channel; S3044, subscriber equipment obtained the MBMS service dispatching information and reads data on the MTCH channel according to the MBMS service dispatching information according to the initial moment of dispatching cycle.
With reference to figure 4, MBMS business scheduling method according to another embodiment of the present invention is described.As shown in Figure 4,2 S-CCPCH that carry MTCH are arranged in certain sub-district, the SCTO=0 that it is corresponding, wherein carried 4 FACH transmission channel FACH1, FACH2, FACH3, FACH4 on the S-CCPCH1, wherein FACH1 carries MSCH logic channel, TTI1=20ms, FACH2, FACH3, FACH4 carry MBMS professional A, B, the MTCH logic channel MTCH a of C, MTCH b, MTCH c respectively, the TTI of professional A, B, C correspondence is respectively TTI2=20ms, TTI3=40ms, TTI3=80ms; Carried some FACH transmission channels on the S-CCPCH2, a FACH wherein is used to carry the MSCH logic channel.Have 3 UE receiving different MBMS business respectively in the sub-district, UE1 receives professional A, and UE2 receives professional B, and UE3 receives professional C.MBMS MSCH_REP=32 dispatching cycle.
As shown in Figure 4, RNC is provided with the MSCH_REP1=32 of S-CCPCH1 correspondence, and MSCH_OFF1=0 is provided with the MSCH_REP2=32 of S-CCPCH2 correspondence, MSCH_OFF2=2, and it is included in the MSCH configuration information sends to UE all in the sub-district by MCCH.The starting point of each dispatching cycle of S-CCPCH1 and S-CCPCH2 2 radio frames that all staggered like this, current dispatching cycle corresponding district SFN is respectively 3200 and 3202.RNC goes up the transmission needs of professional A, B, C according to S-CCPCH1, the service dispatching information that be set the dispatching cycle of S-CCPCH1 is: professional A distributes 2 transmit time segments, the Start=2 of transmit time segments 1, Duration=2, the Start=12 of transmit time segments 2, Duration=2; Professional B distributes 1 transmit time segments, corresponding Start=4, Duration=8; Professional C distributes 1 transmit time segments, corresponding Start=16, Duration=8; RNC sends to UE all in the sub-district in the starting point of this dispatching cycle with service dispatching information; Equally, RNC goes up the service dispatching information that professional transmission needs are provided with S-CCPCH2 according to S-CCPCH2, then the dispatching cycle of S-CCPCH2 starting point send to all UE in sub-district, the setting of schedule information repeats no more in detail.
UE1, UE2, UE3 gets access to the MSCH_REP and the MSCH_OFF of S-CCPCH1 and the last MSCH correspondence of S-CCPCH2 from the MSCH configuration information that MCCH receives, mod MSCH_REP=MSCH_OFF calculates the initial moment of each dispatching cycle according to formula (SFN-(SCTO div 10ms)), and the 1st TTI that starting point begins in dispatching cycle gets access to the MBMS service dispatching information, then, UE1 the 3rd and the 13rd radio frames that starting point begins in the dispatching cycle of S-CCPCH1 begins to read S-CCPCH1 and obtains business datum on the MTCH a, read at every turn and continue 1 TTI, i.e. 2 radio frames, other times are not read the S-CCPCH1 channel; UE2 the 5th TTI that starting point begins in the dispatching cycle of S-CCPCH1 reads S-CCPCH1 and obtains business datum on the MTCH b, continues 2 TTI, i.e. 8 radio frames, and other times are not read the S-CCPCH1 channel; UE3 the 17th TTI that starting point begins in the dispatching cycle of S-CCPCH1 reads S-CCPCH1 and obtains business datum on the MTCH c, continues 1 TTI, i.e. 8 radio frames, and other times are not read the S-CCPCH1 channel.
With reference to figure 5, the multimedia broadcast multicast service scheduling system according to the embodiment of the invention is described.As shown in Figure 5, this multimedia broadcast multicast service scheduling system comprises: service dispatching device 502, be positioned at the radio network controller side, the Transmission Time Interval (TTI) that is used for according to MSCH is provided with the MSCH configuration information, Transmission Time Interval according to MTCH is provided with the MBMS service dispatching information, by the MCCH channel MSCH configuration information is sent to subscriber equipmenies all in the sub-district, by the MSCH channel MBMS service dispatching information is sent to all subscriber equipmenies in the sub-district in initial moment of dispatching cycle; Business information deriving means 504, be positioned at user equipment side, being used for that subscriber equipment is received the MSCH configuration information resolves, and read MBMS service dispatching information on the MSCH channel in the starting point of dispatching cycle according to the MSCH configuration information after resolving, and be used for the MBMS service dispatching information is resolved, and read data on the MTCH channel according to the service dispatching information after resolving.
Wherein, the service dispatching device is provided with MBMS initial moment skew dispatching cycle (MSCH_OFF) of current MSCH channel according to the Transmission Time Interval (TTI) of other MSCH in the current area, dispatching cycle in the initial moment of current MSCH channel was staggered with the dispatching cycle of other MSCH channels in the initial moment, and the radio frames number that staggers is enough to allow other MSCH channels send the MBMS service dispatching information.
Wherein, the service dispatching device is provided with the initial delivery time (START) of MTCH scheduling slot according to the Transmission Time Interval of current MTCH, makes the initial delivery time of each scheduling slot of MTCH channel corresponding to initial moment of the Transmission Time Interval of MTCH.
Wherein, the service dispatching device is provided with the sending duration (DURATION) of MBMS service dispatching period according to the Transmission Time Interval of current MTCH, and the sending duration of MBMS service dispatching period is the integral multiple of the Transmission Time Interval of current MTCH.
Wherein, the service dispatching device also is provided with the MBMS service dispatching cycle (MSCH_REP).
In sum, the present invention is used for solving that existing protocol uses the value of fixed step size to MBMS service dispatching parameter and the problem brought, wherein, when the MSCH configuration information is set with reference to the Transmission Time Interval (TTI) of other MSCH, when the MBMS service dispatching information is set with reference to the Transmission Time Interval of MTCH.According to technical scheme of the present invention, parameter MSCH_OFF in the MSCH configuration information need be with reference to the TTI of other MSCH, the value of MSCH_OFF satisfies allows other MSCH send the MBMS service dispatching information, the Start of MBMS service dispatching period need be with reference to the TTI of MTCH, the starting point of certain TTI of the corresponding MTCH channel of the value of Start, the Duration of MBMS service dispatching period need be with reference to the TTI of MTCH, the value of Duration is the integral multiple of the TTI of MTCH, promptly comprises one or more complete TTI.The power consumption of UE can be farthest saved in the application of the invention, guarantees that UE intactly receives business datum, can also guarantee that the transmission of MBMS service dispatching information on the different MS CH channel is farthest staggered.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.