CN101969677A - Mobile control device, handover control method and mobile communication system - Google Patents

Abstract

The invention provides a mobile control device and a handover control method in a mobile communication system and the mobile communication system. The mobile communication system executes handover control over the switching of communication base stations of the mobile terminal along the movement of the mobile terminal. In the handover control method, the mobile control device selects candidates for more than 1 handover base station according to communication state, determines the transmission speed of multicast communication data according to the communication capability of each handover base station candidates and transmits communication data to each handover base station candidate at the transmission speed, and the handover base station candidate which is determined as the handover base station sends the multicast and the stored communication data to a mobile terminal.

Description

Mobile controller and hand over control method and mobile communication system

The application is to be on December 27th, 2005 applying date, and application number is 200580051579.3, and denomination of invention is divided an application for the application for a patent for invention of " mobile controller and hand over control method ".

Technical field

The present invention relates to mobile controller and hand over control method and mobile communication system, particularly follow moving of portable terminal to switch mobile controller and the hand over control method and the mobile communication system Handoff Control, in the mobile communication system of the base station of this communication of mobile terminal.

Background technology

Figure 30 is to use the structure chart of the mobile communication system of IP (Internet Protocol, Internet Protocol), and mobile controller MCA has wireless base station BTS 1～BTS n and a plurality of mobile terminal MS (only illustrating 1).Mobile controller MCA is connected with IP network as the cable network on upper strata, and, with a plurality of base station BTS 1～BTS n wired connections they are controlled.Mobile terminal MS in base station BTS 1～BTS n and the sub-district CL 1～CL n carries out radio communication.

Never the grouping that illustrated terminal mails to mobile terminal MS sends to the mobile controller MCA that accommodates this portable terminal via IP network.In the time of in mobile terminal MS is in sub-district CL 1, mobile controller MCA sends grouping to the base station BTS 1 of accommodating this sub-district, and base station BTS 1 should grouping to the mobile terminal MS wireless transmission.After, in the time of in mobile terminal MS keeps sub-district CL 1, mobile controller MCA is controlled to mobile terminal MS and the object terminal communicates by above-mentioned path.When mobile terminal MS moved and moves to abutting subdistrict CL 2, mobile controller MCA switched to base station BTS 2 with the base station of relaying from base station BTS 1 by Handoff Control.

In the mobile communication of above-mentioned use IP, consider to use the Mobile IP (mobile IP, RFC 2002, RFC 3775) of mobility (mobility) control that can realize in the IP layer.By in the mobile network, using this technology,, also can continue IP-based communication even such as shown in figure 30 mobile terminal MS changes the base station (handover) that connects the destination in communication.In honeycomb type mobile communication of future generation, also study Mobile IP is imported as the mobility control protocol.In honeycomb type mobile communication of future generation, compare with 3G system as current main flow, require more jumbo high-speed communication, so in order to realize that high-speed packet transmits, and makes the structure of Mobile IP high speed motion essential.

The key character of Mobile IP is that though provided the framework relevant with the signaling that is used to divide into groups to transmit, the concrete standard relevant with grouping transmission control do not provide yet.Therefore, when hope made Mobile IP high speed motion, technology, (2) that need (1) to reduce the delay that signaling causes were used for transmitting at a high speed the load mode of grouping.

As be used to make Mobile IP high speed motion with above-mentioned (1) relevant method, Hierarchical Mobile IPv6 Mobility Management (HMIPv6, the mobile management of multilayer mobile IP v 6) (non-patent literature 1) has been proposed.In addition, as with above-mentioned (2) relevant method, Fast Handovers for Mobile IPv6 (FHO, the quick handover of mobile IP v 6) (non-patent literature 2) has been proposed, to the method (patent documentation 1) of a plurality of mobile candidate's destination base station of portable terminal multicast (multicast) grouping in advance.In addition, also propose the HMIPv6 expansion is had the Hierarchical Mobile IPv6with Buffering (HMIPv6-B, the multilayer mobile IP v 6 of band buffering) (non-patent literature 3) of grouping transmission control method.But, the problem points below in these modes, existing.

The problem points of HMIPv6: HMIP is to be the mode of purpose with the signaling of cutting down among the Mobile IP.Though HMIP does not make any contribution by cutting down the high speed that signaling has realized that grouping transmits for the high speed of tranmission techniques itself.

The problem points of FHO: FHO is the method for speeding up of grouping tranmission techniques.Particularly, be when the handover of portable terminal from the moving source base station to mobile destination base station transmit in advance the method for residual grouping.But, in the method, because mobile destination base station is known to prerequisite, so in the time can't determining the base station of mobile destination, the problem that existence can't divide into groups to transmit.

The problem points of HMIPv6-B: HMIPv6-B appends the pooling feature of grouping and the method for the high speed of the transmission of considering simultaneously to divide into groups to the various functions of HMIPv6.Pooling feature is to be undertaken by the mobile controller of managing a plurality of handovers base station candidate.By this method, can realize reducing the handover of signaling delay and packet loss.But, exist because the buffering of grouping causes the problem points of increase time of delay.

The problem points of multicast: multicast is as shown in figure 31 like that to a plurality of handovers base station of mobile terminal MS candidate BTS 2～BTS 4 method of multicastapackets in advance when handover.

Figure 32 is the structure example that is used to illustrate mobile controller MCA and base station apparatus BTS 1～BTS n of multicast.Mobile controller MCA has: the 101a of wired network interface portion (abbreviating interface as I/F later on), its carry out and IP network between interface control; The 101b of base station I/F portion, its carry out and the base station between interface control; Send data processing division 101c, it carries out the Control on Communication of user grouping and control grouping; And handover/multicast control part 101d, it carries out handover and multicast control.Each base station BTS 1～BTS n has identical structure, has: the mobile controller I/F 102a of portion, its carry out and mobile controller MCA between interface control; The 102b of radio communication I/F portion, its carry out and mobile terminal MS between interface control; Send data processing division 102c, it carries out the Control on Communication of user grouping and control grouping; With the 102d of Handoff Control portion, it carries out Handoff Control.Between mobile controller MCA and each base station BTS 1～BTS n, connect by 1 cable respectively, can pass through control channel, data channel and between them, freely send reception control grouping, user grouping.

Figure 33 is the detailed structure view of mobile controller MCA, focuses on down direction communication and illustrates.In sending data processing division 101c, buffer part 112 and the multicast portion 113 of sending duplicated and is input in the grouping of 111 pairs of inputs of packet copies portion.Send buffer part 112 interim savings input groupings and suitably send to the 101b of base station I/F portion, multicast portion 113 duplicates and via sending buffer part 114a～114c and the base station I/F 101b of portion to handover base station candidate BTS 2～BTS 4 multicasts the grouping of input by handover/multicast control part 101d indication multicast the time.In handover/multicast control part 101d, the integral body of 121 pairs of handovers of Handoff Control portion is controlled, the multicast control when multicast control part 122 is carried out handover.

Figure 34 be when adopting multicast the Handoff Control sequential want portion's key diagram, Figure 35 is the handling process of handover/multicast control part 101d.

When mobile terminal MS and base station BTS 1 communicated, the Handoff Control portion 121 of mobile controller MCA asked mobile terminal MS to be measured and the report wireless status termly.Mobile terminal MS is measured the incoming level from peripheral base station BTS2～BTS n when receiving wireless status mensuration report request, report to mobile controller MCA via the base station BTS 1 in the communication.Handoff Control portion 121 is when receiving this report, judge whether need handover (step 151～152) with reference to the signal level of being reported, when the needs handover, the a plurality of base stations corresponding with the signal level that surpasses threshold value are defined as handover base station candidate (step 153), notify this handover base station candidate to multicast control part 122.In Figure 34, base station BTS 2, BTS 3, BTS 4 are handover base station candidate.

After handover base station candidate determines, multicast control part 122 checks whether distinguished interface IP address, for example MAC Address (the Media Access Control Address of corresponding each base station, Media Access Control Address), when MAC Address is not clear, explore the interface IP address that grouping obtains corresponding base station by sending MAC Address.After these steps finished, 122 pairs of multicast portions of multicast control part 113 carried out the multicast indication.

Thus, 113 pairs of groupings of multicast portion are duplicated and to handover base station candidate BTS 2, BTS 3, BTS 4 multicasts (step 154).

With above-mentioned multicast concurrently, Handoff Control portion 121 determines handover base stations (step 155).For example, be set point when above at received electric field strength from base station BTS 2, this base station BTS 2 is defined as the handover base station.Next, Handoff Control portion 121 these base station BTS 2 setting wireless channels (step 156) of request.Then, carry out following control: set (step 157) when replying receiving wireless channel from base station BTS 2, indication sends grouping to these base station BTS 2 multicasts to mobile terminal MS, and, send the grouping that receives from IP network to mobile terminal MS via base station BTS 2.In addition, multicast control part 122 stops multicast, and indication abandons the grouping to the handover base station candidate's multicast that is not selected as the handover base station, and carries out handover end process (step 158).

Figure 36 be Handoff Control another sequential want portion's key diagram.In this example, suppose also that mobile terminal MS is current to communicate with base station BTS 1, be provided with base station BTS 2～BTS n at the periphery of base station BTS 1.The sequential of mobile controller MCA and Figure 34 is similarly determined handover base station candidate with reference to the received signal level of the peripheral base station of reporting from mobile terminal MS.But, in the sequential example of Figure 34, the report of signal level is carried out via base station BTS 1, but is undertaken by each base station in the present example.In this case, MAC Address is notified in each base station when mobile controller MCA is carried out the report of signal level.Therefore, different with the sequential of Figure 34, mobile controller MCA can carry out multicast immediately and need not to inquire about the interface IP address of base station after determining handover base station candidate.

By utilizing above method of multicasting, mobile terminal MS can receive data from handover base station BTS 2 immediately behind handover, therefore, can realize handover at a high speed.This technology is applicable to the mobile network who uses Mobile IP, so be the strong high-speed packet transfer approach that can improve the problem of HMIPv6, FHO and HMIPv6-B.

But in method of multicasting in the past, the transfer rate of multicast is the transfer rate of the base station that connected before handover according to mobile terminal MS and determining singlely.Therefore, when a plurality of handovers base station candidate's communication capacity there are differences, for example not simultaneously at buffer size or wireless access way, the grouping that certain base station can't collecting post's multicast and produce abandoning of grouping.Therefore, produce time of delay owing to abandoning resending of grouping, generation can't synthetically realize the possibility of high speed handover.Use Figure 31 to illustrate that the grouping in the past the multicast abandons.In Figure 31, illustrate from the example of the residing base station BTS 1 of mobile terminal MS to ensuing handover base station candidate BTS 2～BTS 3 multicasts.Consider that base station BTS 1～BTS 3 is the base stations that are fit to IEEE802.11a (maximum 54Mb/s), base station BTS 4 is the situations that are fit to the base station of 3G (maximum 384Kb/s).In the control of in the past multicast, the transfer rate of multicast is to determine singlely that according to the transfer rate of before this base station BTS 1 its maximum transfer rate is 54Mb/s.

The buffer capacity of each base station is configured to the size corresponding with the transfer rate of wireless access way, so the buffer capacity of handover base station candidate BTS 4 is designed to the buffer capacity less than handover base station candidate BTS 1～BTS 3.Therefore, the maximum transfer rate 384Kb/s that the transfer rate 54Mb/s of the grouping to handover base station candidate BTS 4 multicasts significantly can accommodate greater than NodeB, so all groupings that multicast comes can't be housed in the buffer of base station BTS 4, are dropped owing to buffer overflows.Therefore, when mobile terminal MS is handed over to base station BTS 4, resend the grouping that is abandoned, can't realize the high speed handover owing to follow the time of delay that resends.

This problem not only produces in the handover between different system as above-mentioned example, also produces in the handover in same system.For example, in moving source base station and mobile destination base station, under the extremely different situation of the signal level of portable terminal, produce this problem.

In sum, in the handover of portable terminal, when mobile controller is not considered a plurality of handovers base station candidate's performance and is carried out multicast with single transfer rate, produce grouping owing to buffer overflows a plurality of handovers base station candidate who is arranged in the subordinate and abandon, produce following such problem points.

At first, produce grouping when abandoning overflowing, must resend the grouping that is abandoned, produce the problem that the propagation delay of grouping increases with end-to-end level owing to buffer.Therefore, can't realize the high speed handover.

In addition, in base station BTS 4, because the grouping that multicast comes, the available resource of other portable terminals will reduce, thus produce the mis-behave of these terminals problem, can't accommodate the problem that newly begins the portable terminal of communicating by letter.

Summary of the invention

The object of the present invention is to provide a kind ofly when under Handoff Control, carrying out multicast, in the candidate of handover base station, can not produce mobile controller and the hand over control method that grouping abandons owing to buffer overflows.

Another object of the present invention is to provide a kind of communication capacity of considering each base station (buffer capacity, Radio Resource utilize situation and communication quality QoS (Quality of Service)), and the transfer rate of the multicastapackets that will send the base station is set for and do not produced mobile controller and the hand over control method that grouping abandons.

Non-patent literature 1:Network Working Group Request for Comments 4140 (RFC 4140) " Hierarchical Mobile IPv6 Mobility Management (HMIPv6) "

Non-patent literature 2:Network Working Group Request for Comments 4068 (RFC 4068) " Fast Handovers for Mobile IPv6 "

Non-patent literature 3:VTC-2003 Spring " Transmission Quality Evaluation forHierarchical Mobile IPv6 with Buffering Using Test Bed "

Patent documentation 1: TOHKEMY 2004-282249 communique

Mobile controller and the hand over control method Handoff Control of the base station that the present invention relates to follow moving of portable terminal to switch this communication of mobile terminal, in the mobile communication system.

Hand over control method of the present invention

Hand over control method of the present invention has: the 1st step, according to the candidate of the selected handover base station more than 1 of communications status; The 2nd step is determined the transfer rate of cast communication data according to each handover base station candidate's communication capacity; The 3rd step transmits communication data with this transfer rate to each handover base station candidate; And the 4th step, be confirmed as the communication data that the handover base station candidate of handover base station sends described multicast and preserves to portable terminal.

In described the 2nd step, described communication capacity is the buffer capacity of the buffer that has of each handover base station candidate, determine the transfer rate of cast communication data at each described handover base station candidate according to this buffer capacity, perhaps, the minimum transfer rate among the described handover base station candidate is made as public multicast transfer rate.

In described the 2nd step, described communication capacity is the idle condition of the Radio Resource among each handover base station candidate, determines the transfer rate of cast communication data at each described handover base station candidate according to the idle condition of this Radio Resource.

In described the 2nd step, described communication capacity is the enforceable QoS (service quality) among each handover base station candidate, determines the transfer rate of cast communication data at each described handover base station candidate according to this enforceable QoS.

In described the 3rd step, variation to the communication capacity among the described handover base station candidate in the multicast way detects, change transfer rate adaptively according to this communication capacity after changing, perhaps from the transmission destination of multicast, remove described handover base station candidate and stop multicast at described handover base station candidate's multicast.

Mobile controller of the present invention

Mobile controller of the present invention has: handover base station candidate's determination portion, and it is according to the candidate of the selected handover base station more than 1 of communications status; The transfer rate determination portion, it determines the transfer rate of cast communication data according to each handover base station candidate's communication capacity; Multicast portion, it transmits communication data with this transfer rate to each handover base station candidate; And handover base station determination portion, it is defined as the handover base station with one of described a plurality of handovers base station candidate.

The data that described each handover base station candidate preserves institute's multicast, and the handover base station candidate who is confirmed as the handover base station sends the communication data of this preservation to portable terminal.

Described transfer rate determination portion is considered as described communication capacity with the buffer capacity of the buffer that each handover base station candidate has, determine the transfer rate of cast communication data at each described handover base station candidate according to this buffer capacity, perhaps, the minimum transfer rate among the described handover base station candidate is defined as public multicast transfer rate.

Described transfer rate determination portion is considered as described communication capacity with the idle condition of the Radio Resource among each handover base station candidate, determines the transfer rate of cast communication data at each described handover base station candidate according to the idle condition of this Radio Resource.

Described transfer rate determination portion is considered as described communication capacity with the enforceable QoS (service quality) among each handover base station candidate, determines the transfer rate of cast communication data at each described handover base station candidate according to this QoS.

Described multicast portion has the transfer rate adjustment part, this transfer rate adjustment part with described definite transfer rate to described each handover base station candidate's multicast communication data, this transfer rate adjustment part has buffer, and this buffer is at each preservation of each handover base station candidate and from the communication data speed of network input and the corresponding data of difference of described multicast speed.

When described transfer rate determination portion detects the variation of the communication capacity among the described handover base station candidate in the multicast way, change transfer rate adaptively according to this communication capacity after changing, perhaps from the transmission destination of multicast, remove described handover base station candidate and stop multicast at described handover base station candidate's multicast.

Description of drawings

Fig. 1 is used to illustrate communication system architecture example of the present invention.

Fig. 2 is the structure chart of mobile controller.

Fig. 3 is the structure chart of base station apparatus.

Fig. 4 is a Handoff Control sequential of the present invention.

Fig. 5 is that transfer rate is determined handling process.

Fig. 6 is a handling process of calculating the transfer rate of multicast at each handover base station candidate.

Fig. 7 is the example of message format.

Fig. 8 is the example that shows the message of table 1 with the form of Fig. 7.

Fig. 9 is the example that shows the message of table 2 with the form of Fig. 7.

Figure 10 is the handling process of Handoff Control of the handover/multicast control part of mobile controller.

Figure 11 is that handover stops control and treatment.

Figure 12 is another Handoff Control sequential key diagram of the present invention.

Figure 13 is the effect key diagram of the 1st embodiment.

Figure 14 is the effect key diagram of the 1st embodiment.

Figure 15 is the effect key diagram of the 1st embodiment.

Figure 16 is the effect key diagram of the 1st embodiment.

Figure 17 is the overall diagram of the 2nd embodiment.

Figure 18 is the structure chart with base station of handover/multicast controlled function.

Figure 19 is the Handoff Control sequential of the 2nd embodiment.

Figure 20 is the diagrammatic illustration figure of the 3rd embodiment.

Figure 21 is the state diagram in the handover way.

Figure 22 becomes inadequate resource and stops state to the control of handover base station candidate's multicast.

Figure 23 be the 3rd embodiment the Handoff Control sequential want portion's key diagram.

Figure 24 is the diagrammatic illustration figure of the 2nd mode of the 3rd embodiment.

Figure 25 be the Handoff Control sequential want portion's key diagram.

Figure 26 is the diagrammatic illustration figure of the 3rd mode of the 3rd embodiment.

Figure 27 is a multicast key diagram in the past.

Figure 28 is the multicast key diagram of the 4th embodiment.

Figure 29 is the multicast key diagram of the 2nd mode of the 4th embodiment.

Figure 30 is to use the structure chart of the mobile communication system of IP (Internet Protocol).

Multicast key diagram when Figure 31 is handover.

Figure 32 is the structure example of mobile controller and base station apparatus.

Figure 33 is the detailed structure view of mobile controller.

Figure 34 be when adopting multicast the Handoff Control sequential want portion's key diagram.

Figure 35 is the handling process of handover/multicast control part.

Figure 36 be Handoff Control another sequential want portion's key diagram.

Embodiment

(A) the 1st embodiment

(a) communication system architecture

Fig. 1 is used to illustrate communication system architecture example of the present invention, and mobile controller MCA, wireless base station BTS 1～BTS 5 and a plurality of mobile terminal MS (only illustrating 1) are shown.Mobile controller MCA is connected with the IP network on upper strata, and with a plurality of base station BTS 1～BTS n wired connections they is controlled, and the mobile terminal MS in base station BTS 1～BTS n and the sub-district CL 1～CL n carries out radio communication.

Mobile terminal MS is in base station BTS 1, selects BTS 2～BTS 4 by the handover base station candidate who moves as this portable terminal, and the multicast that mobile controller MCA divides into groups to these base stations transmits.In Fig. 1, base station BTS 1 is the base station that is fit to IEEE 802.11a (54Mb/s), base station BTS 2, BTS 3 are fit to HSDPA (the High Speed Downlink Packet Access of 3GPP, the high-speed downlink packet access) base station (maximum transfer rate 14.4Mb/s), base station BTS 4 are the base stations (maximum transfer rate 384Kb/s) that are fit to 3GPP.

(b) mobile controller

As shown in Figure 2, mobile controller MCA has: wired I/F 1a of portion, it carries out and cable network (IP network) between interface control; The 1b of base station I/F portion, its carry out and the base station between interface control; Send data processing division 1c, it carries out the Control on Communication of user grouping and control grouping; And handover/multicast control part 1d, it carries out handover and multicast control.

In sending data processing division 1c, the grouping of 11 pairs of inputs of packet copies portion is duplicated and is input to transfer rate and adjusts buffer part 12 and multicast portion 13.Multicast portion 13 duplicates and stores into transfer rate to the grouping of input and adjust among buffer part 14a～14c when being indicated multicast by handover/multicast control part 1d.Transfer rate is adjusted buffer part 12,14a～14c and is used to adjust the poor of the input speed of grouping and output speed.Owing to, adjust buffer part 14a～14c so preferably in mobile controller MCA, transfer rate is set at each handover base station candidate at the different possibility of transfer rate that there is multicast in each handover base station candidate.

The grouping that is stored among transfer rate adjustment buffer part 12, the 14a～14c is read according to the multicast transfer rate of indicating from handover/multicast control part 1d in transfer rate adjustment part 15 when handover, be input to and send buffer part 16,17a～17c.Send buffer part 16 and send the input grouping via the base station I/F 1b of portion base station BTS 1 in communication, and, send buffer part 17a～17c put aside temporarily the input grouping and suitably via the base station I/F 1b of portion to handover base station candidate BTS 2～BTS4 multicast.

Usually, adjust buffer part 12 → transfer rate adjustment part 15 → send buffer part 16 → base station 1b of I/F portion from the grouping of IP network via the 1a of cable network I/F portion → packet copies portion 11 → transfer rate, do not send to the base station BTS 1 that communicates with mobile terminal MS with not carrying out the transfer rate adjustment.On the other hand, when under Handoff Control, carrying out multicast, grouping from IP network is duplicated by multicast portion 13, adjust buffer part 14a～14C → transfer rate adjustment part 15 → transmission buffer part 17a～17c → base station I/F 1b of portion via transfer rate, to each handover base station candidate BTS2～BTS 3 multicast.

In handover/multicast control part 1d, the integral body of 21 pairs of handovers of Handoff Control portion is controlled, and multicast control part 22 has multicast control instruction unit 22a and control data sending part 22b.Multicast control instruction unit 22a carries out multicast to the 13 notice handover base station candidate BTS 2～BTS 4 of multicast portion, and, communication capacity according to handover base station candidate BTS 2～BTS 4 is determined the multicast transfer rate, to transfer rate adjustment part 15 these transfer rates of input.Control data sending part 22b obtains and keeps the data such as communication capacity of each base station from each handover base station candidate BTS 2～BTS 4 by the control grouping.

(c) base station

Fig. 3 is the structure chart of base station BTS 1～BTS n, and each base station has identical structure.The base station has: the mobile controller I/F 2a of portion, its carry out and mobile controller MCA between interface control; The 2b of radio communication I/F portion, its carry out and mobile terminal MS between interface control; Send data processing division 2c, it carries out the Control on Communication of user grouping and control grouping; The 2d of Handoff Control portion, it carries out Handoff Control; Control information sending part 2e, it sends the control grouping to mobile controller MCA; With the 2f of communications status management department.The 2f of communications status management department is the part that the state of communication capacity to the expression base station manages, have the management buffer capacity cache management portion 31, managing radio resources state (behaviours in service of channel, frequency band etc.) RRM portion 32 and manage the communication quality management department 33 of executable communication quality (QoS).Between mobile controller MCA and each base station BTS 1～BTS n, connect by 1 cable respectively, can pass through control channel, data channel and between them, freely send reception control grouping, user grouping.

(d) Handoff Control sequential

Fig. 4 is a Handoff Control sequential of the present invention.

When mobile terminal MS and base station BTS 1 communicate (with reference to Fig. 1), the Handoff Control portion 21 of mobile controller MCA asks mobile terminal MS to be measured and the report wireless status termly.Mobile terminal MS is measured the incoming level from peripheral base station BTS 2～BTS n when receiving wireless status mensuration report request, report to mobile controller MCA via the base station BTS 1 in the communication.

Handoff Control portion 21 is when receiving this report, judge whether need handover with reference to the signal level of being reported, when the needs handover, the base station 1 or more corresponding with the signal level that surpasses threshold value is defined as handover base station candidate, notifies this handover base station candidate to multicast control part 22.In Fig. 4, base station BTS 2, BTS 3, BTS 4 are handover base station candidate.

After handover base station candidate determined, the multicast of multicast control part 22 control instruction unit 22a checked the MAC Address of whether having distinguished corresponding each base station, when MAC Address is not clear, explored the interface IP address that grouping obtains corresponding base station by sending MAC Address.After these steps finished, multicast control instruction unit 22a paired domination number was controlled according to sending part 22b, carries out sending by message the control of the information of the communication capacity that obtains each handover base station candidate BTS 2～BTS 4 of expression.In addition, the information of obtained expression communication capacity is used for determining the multicast transfer rate.

The state of the communication capacity of expression base station comprises:

(1) buffer capacity that can guarantee;

(2) idle condition of Radio Resource;

(3) could guarantee QoS that portable terminal is wished etc.

At this, control data sending part 22b sends the control grouping of above-mentioned each state of investigation to each handover base station candidate BTS 2～BTS 4.By the report from the base station with reference to the control grouping of investigating usefulness at this communication capacity, multicast control instruction unit 22a holds the communication capacity of each handover base station candidate BTS 2～BTS 4, determines the multicast transfer rate according to this communication capacity.

The communication capacity investigation message that control data sending part 22b sends and the communication capacity report message of base station report can show shown in table 1, table 2 respectively like that.In addition, table 1 illustrates the example that could not guarantee QoS to the base station investigation.

(table 1)

The control messages that mobile controller sends (investigation request is not carried out in * expression)

	?BTS?2	BTS?3	BTS?4	BTS?5
					(1) buffer capacity	?○	○	○	×
(2) resource idle condition	?○	○	○	×
					(3) could guarantee QoS	?×	×	×	×

(table 2)

The communication capacity report message that the base station sends

?BTS?2

BTS?3

BTS?4

BTS?5

(1) buffer capacity	?7Mb	7Mb	192Kb	×
					(2) resource idle condition	?1	1	1	×
(3) could guarantee QoS	?×	×	×	×

Could not guarantee that to base station investigation the reason of QoS is, suppose TCP (Transmission Control Protocol, transmission control protocol) as data transfer protocol end to end.In addition, because base station BTS 5 is not handover base station candidate, do not divide into groups with control so do not send investigation.In addition, in table 2, the buffer capacity that (1) expression can actually be guaranteed.At the hypothesis handoff time is 500ms and each base station can guarantee the buffer capacity suitable with maximum transfer rate the time, in BTS2～BTS 4, can guarantee buffer capacity 7 (=14.4 * 0.5) Mb shown in the table 2,7Mb, 192 (=384 * 0.5) kb.In the row (2) of table 2, the value of being illustrated in is can't guarantee Radio Resource under 0 the situation, in value is can guarantee Radio Resource under 1 the situation.In addition, similarly, the value of being illustrated in be for can't providing the QoS of mobile terminal request under 0 the situation in the row (3) of table 2, and the QoS of mobile terminal request can be provided under for 1 situation in value.

As mentioned above, multicast control instruction unit 22a uses this information to determine the multicast transfer rate when the information of the communication capacity that obtains each handover base station candidate BTS2～BTS 4 of expression.

Fig. 5 is that transfer rate is determined handling process.Multicast control instruction unit 22a is initialized as 0 (step 201) with i, then, make the i stepping and, receive the report message (step 205) of reporting communication capacity from each handover base station candidate BTS i to the control messages (step 202～204) that each handover base station candidate BTS i sends communication capacity investigation usefulness.By the control of this step 202～204,22a is when receiving buffer capacity Bi (b) at i handover base station candidate BTS i for multicast control instruction unit, passes through following formula

Fi(b/s)＝Bi/HO#TIME

Transfer rate (transfer rate can the be provided) Fi (b/s) (step 206) that calculating can provide portable terminal BTS i.Wherein, HO#TIME is a handoff time.Next, obtain all handover base station candidate BTS i (i=1,2 ..., m) provided transfer rate Fi (b/s) (i=1,2 ..., m), wherein minimum provided transfer rate Mi is provided, the provided transfer rate Mi of this minimum is made as public multicast transfer rate at each handover base station candidate BTS i.

In Fig. 5, in step 207, obtain public multicast transfer rate, but also can calculate the transfer rate of multicast at each handover base station candidate BTS i at each handover base station candidate BTS i.Fig. 6 is a handling process of calculating the transfer rate of multicast at each handover base station candidate BTS i, and Ri (b/s) is the maximum transfer rate that sends among the candidate BTS i of handover base station.Step 201～206 are identical with the flow process of Fig. 5.

Obtain by step 206 all handover base station candidate BTS i (i=1,2 ..., m) in provided transfer rate Fi (b/s) (i=1,2 ..., m) after, multicast control instruction unit 22a is initialized as 0 (step 301) with i, then, make i stepping (step 302).Afterwards, less transfer rate among the maximum transfer rate Ri (b/s) that sends of the provided transfer rate Fi (b/s) of handover base station candidate BTS i and handover base station candidate BTS i is provided and is made as Mi (step 303), at all handover base station candidate BTS i (i=1,2 ..., m) repeat above-mentioned processing (step 304), Mi is made as multicast transfer rate (step 305) at handover base station candidate BTS i.

After the transfer rate of multicast was determined, multicast control instruction unit 22a carried out the multicast indication to multicast portion 13, and, to transfer rate adjustment part 15 input multicast transfer rates.Thus, 13 pairs of groupings of multicast portion are duplicated and are input to transfer rate and adjust buffer part 14a～14c.In addition, multicast portion 13 is for the grouping of distinguishing multicast and common grouping, to the multicastapackets attach identifier.

Transfer rate adjustment part 15 is according to the multicast transfer rate at each handover base station candidate BTS 2, BTS 3, BTS 4, adjust buffer part 14a～14c from transfer rate and read grouping, via sending buffer part 17a～17c, the base station I/F 1b of portion to each handover base station candidate BTS 2, BTS 3, BTS 4 multicasts.

With above-mentioned multicast concurrently, Handoff Control portion 21 determines the handover base stations.For example, be set point when above at received electric field strength from base station BTS 2, this base station BTS 2 is defined as the handover base station.Next, Handoff Control portion 21 carries out radio bearer setting request (RB Setup request) to this base station BTS 2.Then, set when replying (RB Setup replys) receiving radio bearer from base station BTS 2, send hand-off request (HO indication) to mobile terminal MS via base station BTS 1.Thus, mobile terminal MS is carried out from the handover of base station BTS 1 to base station MTS 2, sends handover to base station BTS 2 and reply (HO replys) after carrying out handover.

Base station BTS 2 is replied the grouping that sends institute's multicast and keep to mobile terminal MS by handover, and, send data transmission requests to mobile controller MCA.Mobile controller MCA stops multicast by data transmission requests, and, send the grouping that receives from IP network to mobile terminal MS via base station BTS 2 later on.Thus, base station BTS 2 sends handover to mobile controller MCA and finishes notice, and the multicast control instruction unit 22a indication of mobile controller MCA abandons to the handover base station candidate BTS 3 that is not selected as the handover base station, the grouping of BTS4 multicast.

Grouping by carrying out from institute's multicast to the control messages shown in handover base station candidate BTS 3, the BTS 4 transmission tables 3 abandon indication.

(table 3)

The control messages that mobile controller sends (investigation request is not carried out in * expression)

	?BTS?3	BTS?4
			(1) buffer capacity	×	×
(2) resource idle condition	×	×
			(3) could guarantee QoS	×	×
(4) carry out abandoning of grouping	1	1

Fig. 7 is the example of message format, (a) is from the form example of base station BTS i to the message of mobile controller MCA, (b) is from the form example of mobile controller MCA to the message of base station BTS i.

In message format, (1)～(4) are the message sequence number, (1) buffer capacity for guaranteeing, and (2) are the idle condition of Radio Resource, (3) for could guarantee the QoS that portable terminal is wished, (4) are for carrying out abandoning of grouping.The buffer capacity of message sequence number (1) shows with 8, and message sequence number (2)～(4) show with 1.In addition, base station IDs shows with 8, from base station BTS 1 be made as 00000001,00000010,00000011 successively ...The ID of mobile controller MCA is 00001000.Identification shows with 1, is " 1 " under with reference to the situation in this territory, is " 0 " under the situation of not reference.In addition, unit shows with 3, and 100 is Gb/s, and 010 is Mb/s, and 001 is Kb/s.

Fig. 8 is the example that shows the message of table 1 with the form of Fig. 7, (a) be from the communication capacity investigation message of mobile controller MCA to base station BTS 2, (b) be from the communication capacity investigation message of mobile controller MCA, (c) for using message to the communication capacity investigation of base station BTS 4 from mobile controller MCA to base station BTS 3.

Fig. 9 is the example that shows the message of table 2 with the form of Fig. 7, (a) be from the communication capacity report message of base station BTS 2 to mobile controller MCA, (b) be from the communication capacity report message of base station BTS 3, (c) for using message to the communication capacity report of mobile controller MCA from base station BTS 4 to mobile controller MCA.

(e) handling process of Handoff Control

Figure 10 is the handling process of Handoff Control of handover/multicast control part 1d of mobile controller MCA.

The signal level that Handoff Control portion 21 measures with reference to mobile terminal MS need to judge whether handover, when the needs handover, the base station corresponding with the signal level that surpasses threshold value is defined as handover base station candidate (step 401).

After handover base station candidate determined, multicast control part 22 carried out obtaining by the message transmission control (step 402) of the information of the communication capacity of representing each handover base station candidate BTS 2～BTS 4.Afterwards, need to judge whether the speed adjustment (step 403) of multicast transfer rate, determine transfer rate (step 404) according to the flow process of Fig. 5 or Fig. 6 when needed, come multicast (step 405) with this transfer rate.

With above-mentioned multicast concurrently, Handoff Control portion 21 determines the handover base stations, and, carry out radio bearer to this handover base station (being made as base station BTS 2) and set request (step 406).Then, set (step 407) when replying receiving radio bearer from base station BTS 2, multicast control part 22 stops multicast, and indication sends grouping (step 408) to base station BTS 2 multicasts to mobile terminal MS.Next, Handoff Control portion 21 carries out handover end process (step 409).After, mobile controller MCA is controlled to via base station BTS 2 and sends the grouping that receives from IP network to portable terminal BS.

Handover in step 409 stops in the control, Handoff Control portion 21 shown in step 409a～409d of Figure 11, indication abandon handover base station candidate BTS i beyond the base station BTS k that is selected as the handover base station (i=1,2 ..., k-1, k+1 ..., m) grouping of multicast.Be instructed to abandon grouping handover base station candidate BTS i (i=1,2 ..., k-1, k+1 ..., m) abandon the additional grouping that the multicastapackets identifier is arranged.

Figure 12 is another Handoff Control sequential key diagram of the present invention.In this sequential, send the control messages (with reference to table 1) that message and communication capacity investigation usefulness are explored in address in the sequential of Fig. 4 simultaneously, simultaneously receiver address notification message and communication capacity report message (with reference to table 2).Like this, receive 2 message, can reduce message and send receive delay by sending simultaneously.

(f) effect of the 1st embodiment

Figure 13～Figure 16 is the effect key diagram of the 1st embodiment.Wherein, suppose mobile terminal MS from base station BTS 1 to base station BTS 4 handovers.

As shown in figure 13, suppose after base station BTS 1 transmission of moving source is accomplished to dataA to produce handover, and after the supposition data B that sends to mobile controller MCA from IP network is carried out multicast and transmit.

At this moment, when mobile terminal MS averages TCP (Transmission Control Protocol, transmission control protocol) when communication of throughput 1Mb/s, transmit the data of 500Kb during as the 500ms of handoff time.Therefore, abandon for fear of grouping when handover, base station BTS 4 need be guaranteed the buffer capacity of 500Kb at least.Figure 14 illustrates in the past the method for multicasting situation behind the handover just.In previous methods, owing to carry out multicast with 1Mb/s as the transfer rate of the TCP of base station BTS 1 communication, so during 500ms, to the data of base station BTS 4 multicast 500Kb as handoff time.But the buffer BF4 maximum of base station BTS 4 also only can be guaranteed the buffer capacity of 192Kb, so divide into groups to abandon owing to buffer overflows to produce.Because the controlling organization that resends end to end by TCP comes the grouping that is abandoned is resend, so produce time of delay owing to resending.

On the other hand, according to the 1st embodiment, the buffer capacity of the buffer BF 4 of mobile controller MCA consideration base station BTS 4 (=192Kb) determine the multicast transfer rate according to the handling process of Fig. 5.For example, as shown in figure 15, the transfer rate of multicast is defined as 380Kb/s singlely.Like this, after the multicast transfer rate was determined, during the 500ms as handoff time, to the data of base station BTS 1 and base station BTS 4 multicast 190Kb, remaining data savings was adjusted among buffer part 12, the 14c in the transfer rate of mobile controller MCA.By this control, the grouping that can avoid producing in the previous methods abandons, the TCP communication that mobile terminal MS can begin to divide into groups behind the handover just.Therefore, can avoid following the communication of the time of delay that resends control of TCP.

In addition, as shown in figure 16, mobile controller MCA is according to the handling process of Fig. 6, can be according to the communication capacity (buffer capacity) of each base station BTS 1, BTS 4 transfer rate during at each base station sets multicast.For example, carry out the transmission of data with 1Mb/s, to the transfer rate transmission data of BTS4 with 380Kb/s to base station BTS 1.Thus, during 500ms,,,, buffer divides into groups to abandon owing to overflowing to produce to the data of base station BTS 4 transmission 190Kb to the data of base station BTS 1 transmission 500Kb as handoff time.At this moment, adjust the data of buffer part 14c savings 310Kb to the transfer rate that is arranged on the base station BTS 4 on the mobile controller MCA.

(B) the 2nd embodiment

(a) summary

In the 1st embodiment, suppose that mobile controller MCA is positioned at the upper strata of base station.But, in the 2nd embodiment, make the base station that has communicated before this have handover/multicast controlled function.

Figure 17 is the overall diagram of the 2nd embodiment, the base station BTS 1 that has communicated with mobile terminal MS before the handover carries out Handoff Control and judges whether handover, under the situation of handover, determine handover base station candidate BTS 2～BTS 4, communication capacity according to each handover base station candidate BTS 2～BTS 4 is determined the multicast transfer rate, with this multicast transfer rate to each handover base station candidate BTS 2～BTS 4 multicastapackets.In addition, base station BTS 1 is determined the handover base station concurrently with multicast, and, make this handover base station (being made as base station BTS 2) setting wireless channel, stop multicast then, and indication is to the grouping of mobile terminal MS transmission to base station BTS 2 multicasts.Next, base station BTS 1 carries out the handover end process, and indication abandons the handover base station candidate BTS 3 beyond the base station BTS 2 that is selected as the handover base station, the grouping of BTS 4 multicasts.

(b) structure of base station

Figure 18 is the structure chart with base station BTS 1 of above-mentioned handover/multicast controlled function, has Fig. 2 of the 1st embodiment, mobile controller shown in Figure 3 and this two side's of base station structure.That is, in base station BTS 1, have: the mobile controller I/F 3a of portion, its carry out and mobile controller MCA between interface control; The 3b of wireless communication interface portion, its carry out and mobile terminal MS between interface control; Send data processing division 3c, it carries out user grouping and the Control on Communication of control grouping and the multicast of grouping; The 3d of Handoff Control portion, it carries out Handoff Control as the base station; The 3e of communications status management department, it represents the state of communication capacity as BTS management; And handover/multicast control part 3f, it carries out the handover and the multicast control of entire system.

In sending data processing division 3c, the grouping of 41 pairs of inputs of packet copies portion is duplicated and is input to transfer rate and adjusts buffer part 42 and multicast portion 43.Multicast portion 43 duplicates and stores into transfer rate to the grouping of input and adjust among buffer part 44a～44c when being indicated multicast by handover/multicast control part 3f.Transfer rate is adjusted buffer part 42,44a～44c and is used to adjust the poor of the input speed of grouping and output speed.

The grouping that is stored among transfer rate adjustment buffer part 42, the 44a～44c is read according to the multicast transfer rate of indicating from handover/multicast control part 3f in transfer rate adjustment part 45 when handover, be input to and send buffer part 46,47a～47c.The 46 interim savings inputs of transmission buffer part divide into groups also suitably to send to mobile terminal MS via the base station I/F 3b of portion, in addition, send buffer part 47a～47c and put aside the input grouping also suitably to handover base station candidate BTS 2～BTS 4 multicasts temporarily.

The 3e of communications status management department is the part that the state of communication capacity to the expression base station manages, have the management buffer capacity cache management portion 51, managing radio resources state (behaviours in service of channel, frequency band etc.) RRM portion 52 and manage the communication quality management department 53 of executable communication quality (QoS).

In handover/multicast control part 3f, the integral body of 61 pairs of handovers of Handoff Control portion is controlled, and multicast control part 62 has multicast control instruction unit 62a and control data sending part 62b.Multicast control instruction unit 62a carries out multicast to the 43 notice handover base station candidate BTS 2～BTS 4 of multicast portion, and, communication capacity according to handover base station candidate BTS 2～BTS 4 is determined the multicast transfer rate, to transfer rate adjustment part 45 these transfer rates of input.Control data sending part 62b is by dividing into groups to obtain and keep the data such as communication capacity of each base station from the control of each handover base station candidate BTS 2～BTS 4.

(c) Handoff Control sequential

Figure 19 is the Handoff Control sequential of the 2nd embodiment, with communication of mobile terminal in base station BTS 1 carry out the control of handover/multicast aspect sequential with Fig. 4 different.

Ask mobile terminal MS to be measured and the report wireless status termly with the Handoff Control portion 61 of base station BTS 1 in the communication of mobile terminal.Mobile terminal MS is measured the incoming level from peripheral base station BTS 2～BTS n when receiving wireless status mensuration report request, report to the base station BTS 1 in the communication.

Handoff Control portion 61 is when receiving this report, judge whether need handover with reference to the signal level of being reported, when the needs handover, the a plurality of base stations corresponding with the signal level that surpasses threshold value are defined as handover base station candidate, notify this handover base station candidate to multicast control part 62.

After handover base station candidate determined, the multicast of multicast control part 62 control instruction unit 62a checked the MAC Address of whether having distinguished corresponding each base station, when MAC Address is not clear, explored the interface IP address that grouping obtains corresponding base station by sending MAC Address.After these steps finish, multicast control instruction unit 62a paired domination number is controlled according to sending part 62b, send the information that obtains the communication capacity of representing each handover base station candidate BTS 2～BTS 4 by message, use the information of this communication capacity of expression to determine the multicast transfer rate.

After the transfer rate of multicast was determined, multicast control instruction unit 62a carried out the multicast indication to multicast portion 43, and, to transfer rate adjustment part 45 input multicast transfer rates.Thus, 43 pairs of groupings of multicast portion are duplicated and are input to transfer rate and adjust buffer part 44a～44c.In addition, multicast portion 43 is for the grouping of distinguishing multicast and common grouping, to the multicastapackets attach identifier.

Transfer rate adjustment part 45 is according to the multicast transfer rate at each handover base station candidate BTS 2, BTS 3, BTS 4, adjust buffer part 44a～44c from transfer rate and read grouping, via sending buffer part 47a～47c to each handover base station candidate BTS 2, BTS 3, BTS 4 multicasts.

With above-mentioned multicast concurrently, Handoff Control portion 61 determines handover base stations (supposition base station BTS 2 is handover base stations).Next, Handoff Control portion 61 carries out radio bearer setting request (RB Setup request) to this base station BTS 2.Then, set when replying (RB Setup replys) receiving radio bearer from base station BTS 2, mobile terminal MS is carried out hand-off request (HO indication).Thus, mobile terminal MS is carried out from the handover of base station BTS 1 to base station MTS 2, sends handover to base station BTS 2 and reply after carrying out handover.

Base station BTS 2 is replied the grouping that sends institute's multicast and keep to mobile terminal MS by handover, and, send data transmission requests to mobile controller MCA.Mobile controller MCA stops multicast by data transmission requests, and, send the grouping that receives from IP network to mobile terminal MS via base station BTS 2.Thus, base station BTS 2 sends handover to base station BTS 1 and finishes notice, and the multicast control instruction unit 62a indication of base station BTS 1 abandons the grouping to the handover base station candidate BTS 3 that is not selected as the handover base station, BTS 4 multicasts.

According to the 2nd embodiment, can enumerate and compare constructing of the mobile communication system simple feature that becomes with the 1st embodiment.That is, in the 1st embodiment, need mobile controller and base station to carry out multicast linkedly and transmit control, transmit control but in the 2nd embodiment, can carry out multicast separately by the base station.

(C) the 3rd embodiment

(a) the 1st mode of the 3rd embodiment

In the 1st, the 2nd embodiment, suppose from handover to begin till finish that the transfer rate during multicast does not change.But, owing to the communication conditions of base station changes constantly, so the communication capacity variation of base station in the handover way sometimes.The 3rd embodiment is the embodiment of the situation of considering that the communication capacity of base station in the handover way changes, and mobile controller and base station have Fig. 2, structure shown in Figure 3.

Figure 20 is the diagrammatic illustration figure of the 3rd embodiment, and mobile controller MCA is positioned at the upper strata of base station BTS i.Mobile controller MCA is owing to moving of mobile terminal MS carried out Handoff Control, and is current to handover base station candidate BTS 2, BTS 3, BTS 4 multicastapackets.Under above-mentioned state, the communication capacity of handover base station candidate BTS 4 reduces, when become owing to buffer overflow produce the grouping abandon state the time, when perhaps Radio Resource is not enough, in the time of perhaps can't satisfying the QoS of mobile terminal request, mobile controller MCA stops the multicast to handover base station candidate BTS 4.

Figure 21 is the state in the handover way, and 2 handover base station candidate BTS 2, BTS 4 are shown.BF is a buffer, with the buffer size that BF 2, BF 4 represent each base station, represents idle component with white.RM is a Resource Manager, with the stock number (for example frequency band) that RM 2, RM 4 represent each base station, represents not use stock number (but service band) partly with white.

Suppose that handover base station candidate BTS can guarantee buffer capacity when 4 multicasts at data A begin, but in the multicast way of this data A, can't utilize Radio Resource.When the portable terminal that is higher than the QoS of the mobile terminal MS in the communication when the request level newly is connected to handover base station candidate BTS 4, produce above-mentioned condition.This is because will cause inadequate resource (frequency band deficiency) to the portable terminal priority allocation Radio Resource of asking higher QoS.When inadequate resource, the mobile terminal MS that handover base station candidate BTS 4 can't accommodate in the communication.

Figure 22 illustrates because of inadequate resource and stops state to the control of the multicast of handover base station candidate BTS 4.

In order to carry out the control that stops of multicast because of inadequate resource, send the communication capacity report message shown in the table 4 to mobile controller.

(table 4)

The communication capacity report message that the base station sends adaptively

	?BTS?4
		(1) buffer capacity	?192Kb

(2) resource idle condition	?0
		(3) could guarantee QoS	?×

In addition, according to the form of Fig. 7, this communication capacity report message is as shown in table 5.

(table 5)

The communication capacity report message

00000100

00001000

111000000001

10

00

00

The mobile controller MCA identification that receives above-mentioned communication capacity report message can't be guaranteed the situation of Radio Resource, removes base station BTS 4 from the candidate of handover base station, and stops the multicast transmission, notifies stopping of this multicast to base station BTS 4.In addition, with the multicast expiry notification, mobile controller MCA indication base station BTS 4 abandons the grouping that multicast is finished.Abandon indication by implement grouping to the control messages of base station BTS 4 transmission tables 6.

(table 6)

The control messages that grouping abandons (investigation request is not carried out in * expression)

	?BTS?4
		(1) buffer capacity	?×
(2) resource idle condition	?×
		(3) could guarantee QoS	?×
(4) carry out abandoning of grouping	?1

In addition, according to the form of Fig. 7, the control messages that grouping abandons is as shown in table 7.

(table 7)

The control messages that grouping abandons

00001000

00000100

00

00

00

11

By above control, even stop to the multicast transmission of base station BTS 4, mobile controller MCA also continues the handover base station candidate BTS 2 beyond base station BTS 4, the data A that BTS 3 multicasts arrive from the upper strata.

Figure 23 be the 3rd embodiment the Handoff Control sequential want portion's key diagram, illustrate from the transmission of the message (table 1) of communication capacity investigation usefulness and be timed to the sequential that multicast continues.

After handover base station candidate determined, mobile controller MCA sent the information that reception obtains the communication capacity of each handover base station candidate BTS 2～BTS 4 of expression by message, used the information of this communication capacity of expression to determine the multicast transfer rate.

After the transfer rate of multicast was determined, mobile controller MCA began multicast.In this multicast, handover base station candidate BTS 4 sends the communication capacity report message shown in the table 4 to mobile controller MCA when the variation that detects communication capacity.When receiving this communication capacity report message, mobile controller MCA stops to transmit to the multicast of base station BTS 4, indicates grouping to abandon to the control messages of base station BTS 4 transmission tables 6.After, mobile controller MCA continues to transmit the grouping that arrives from the upper strata to handover base station candidate BTS 2, BTS 3 multicasts.Later sequential is identical with Fig. 4.

As mentioned above, according to the 1st mode of the 3rd embodiment, by from the transmission destination that multicast transmits, removing handover base station candidate at once, and abandon before this grouping, thereby can more effectively utilize Internet resources the base station multicast of removing.

(b) the 2nd mode of the 3rd embodiment

In above-mentioned the 1st mode, mobile controller MCA sends owing to handover base station candidate's communication capacity reduction and from multicast and removes this base station the destination, and, stop to transmit to the multicast of this base station.But, exist Radio Resource to produce the free time once more, handover base station candidate BTS4 becomes and can accommodate the possibility of mobile terminal MS.Therefore, in the 2nd mode of the 3rd embodiment, when causing to utilize the Radio Resource of base station BTS 4 owing to the communication capacity reduction, be not to send to remove the destination and stop multicast from multicast at once to transmit, but the transfer rate of multicast is set at 0, can when recovering, communication capacity carry out multicast thus.

Figure 24 is the diagrammatic illustration figure of the 2nd mode of the 3rd embodiment, Radio Resource as handover base station candidate BTS 4 in the multicast of data A way is shown when not enough, will be made as 0 state to the transfer rate of the multicast of base station BTS 4.

Because the data A that arrives from IP network is sent successively, so in the transfer rate adjustment buffer part 14a of mobile controller MCA, be not detained data.On the other hand, owing to will be made as 0 to the multicast transfer rate of handover base station candidate BTS 4, the data A that arrives from IP network is not sent out and is trapped in the transfer rate adjustment buffer part 14c.But, when the communication capacity of handover base station candidate BTS 4 is recovered, send the data that are trapped among the transfer rate adjustment buffer part 14c to this base station BTS 4.

Figure 25 be the 2nd mode the Handoff Control sequential want portion's key diagram, illustrate from the transmission of the message (table 1) of communication capacity investigation usefulness and be timed to the sequential that multicast continues.

After handover base station candidate determined, mobile controller MCA sent the information that reception obtains the communication capacity of each handover base station candidate BTS 2～BTS 4 of expression by message, used the information of this communication capacity of expression to determine the multicast transfer rate.After the transfer rate of multicast was determined, mobile controller MCA began multicast.In this multicast, handover base station candidate BTS 4 sends the communication capacity report message shown in the table 8 to mobile controller MCA when the variation that detects communication capacity.

(table 8)

The communication capacity report message

	?BTS?4
		(1) buffer capacity	?0Kb
(2) resource idle condition	?1
		(3) could guarantee QoS	?×

In addition, according to the form of Fig. 7, the grouping of communication capacity report message is as shown in table 9.

(table 9)

The communication capacity report message

00000100

00001000

100000000000

11

00

00

When receiving this communication capacity report message, because the resource idle condition is that " 1 " (being " 0 " in the table 4) and buffer capacity are 0Kb, so mobile controller MCA will be made as 0 to the multicast transfer rate of base station BTS 4.

After, the grouping that mobile controller MCA continuation arrives from the upper strata to handover base station candidate BTS 2, BTS 3 multicasts.Later sequential is identical with Fig. 4.

According to the 2nd mode of the 3rd embodiment, under the situation that communication capacity reduces, the multicast transfer rate is made as 0, when communication capacity is recovered, restore transfer rate, thereby can continue multicast.

(c) the 3rd mode of the 3rd embodiment

In the 2nd mode, illustrate because the communication capacity reduction causes handover base station candidate BTS 4 can't accommodate the situation of mobile terminal MS.But handover base station candidate BTS 4 by reducing the transfer rate that mobile terminal MS is provided, guarantees the bandwidth at this mobile terminal MS sometimes, can accommodate mobile terminal MS thus.Figure 26 is the summary description figure of the 3rd mode of the 3rd embodiment, illustrate when the Radio Resource of handover base station candidate BTS 4 in the multicast of data A way reduces, mobile controller MCA will be made as the state of the transfer rate corresponding with the Radio Resource of this base station to the transfer rate of the multicast of base station BTS 4.

In the 2nd mode, the transfer rate of multicast is made as 0Kb/s and stops multicast on the surface.But in the 3rd mode,, continue multicast by reducing the transfer rate (for example changing to 64Kb/s) that 4 couples of portable terminal BS of base station BTS provide from 384Kb/s.

The sequential of the 3rd mode is identical with Figure 25, but the report message difference that base station BTS 4 sends to mobile controller MCA.Promptly, in the 2nd mode, as shown in table 8, the value of buffer capacity is 0Kb, but in the 3rd mode, as shown in table 10, for the data of sending during being received in 500ms for example, with the transfer rate of 64Kb/s, but buffer capacity is made as the current service band 32Kb of base station BTS 4 as handoff time.

(table 10)

The communication capacity report message

	?BTS?4
		(1) buffer capacity	?32Kb
(2) resource idle condition	?1
		(3) could guarantee QoS	?×

In addition, according to the form of Fig. 7, above-mentioned communication capacity report message is as shown in table 11.

(table 11)

The communication capacity report message

00000100

00001000

100100000000

11

00

00

Because the data A that arrives from IP network is sent successively, so in the transfer rate adjustment buffer part 14a of mobile controller MCA, be not detained data.On the other hand, owing to the multicast transfer rate to handover base station candidate BTS 4 is below the input speed of data A, is trapped in transfer rate so the data A corresponding with its difference is not sent out and adjusts among the buffer part 14c.

The 3rd mode according to the 3rd embodiment, under the situation that handover base station candidate's communication capacity reduces, the multicast transfer rate is made as the communication capacity corresponding value remaining with this base station candidate, can continue multicast thus, even the candidate is selected as under the situation of handover base station in this handover base station, also can communicate with portable terminal.

(D) the 4th embodiment

(a) the 1st mode

In the 1st embodiment, suppose TCP as communication protocol end to end.In the 4th embodiment, conduct communication protocol end to end is described, suppose to be used for the situation of the UDP (User Datagram Protocol, User Datagram Protoco (UDP)) of real time communication.Suppose that mobile terminal MS carries out the stream communication of 1Mb/s, and the QoS of the transfer rate of 1Mb/s is satisfied in the mobile terminal MS request.

Figure 27 is a multicast key diagram in the past, and Figure 28 is the multicast key diagram of the 4th embodiment, and 2 handover base station candidate BTS 2, BTS 4 are shown.In Figure 27, Figure 28, BF is a buffer, with the buffer size that BF 2, BF 4 represent each base station, represents idle component with white.QM is QoS manage person, represents the enforceable QoS level in each base station with QM 2, QM 4.

In the example in the past of Figure 27, mobile controller MCA does not investigate the QoS that handover base station candidate BTS 4 could provide mobile terminal request.Therefore, under the situation of the QoS that can't satisfy mobile terminal request, cause carrying out futile multicast owing to buffer overflows to produce to divide into groups to abandon like that as shown in the figure, vainly utilize Internet resources.

But according to the 4th embodiment, mobile controller MCA can obtain each handover base station candidate's communication capacity before multicast begins, and identification handover base station candidate BTS 4 could provide the QoS of mobile body terminal request.Then, mobile controller MCA removes handover base station candidate BTS4 from the multicast destination when being judged as the QoS that mobile terminal request can't be provided, and does not carry out the multicast of the data that transmit from the streaming server of communication object.Thus, can prevent under the situation that can't satisfy QoS, to produce grouping and abandon, and can effectively utilize Internet resources.

(b) the 2nd mode

Can't carry out as long as reduce the quality of image or voice, just can keeping stream communication under the situation of this portable terminal as the stream communication of the 1Mb/s of QoS request the handover base station of mobile terminal MS candidate.In the 2nd mode,, when being moved terminal request and keeping stream communication, also carry out multicast with the transfer rate corresponding with the handover base station available QoS of candidate even can't satisfy the QoS of mobile terminal request.

Figure 29 is the multicast key diagram of the 2nd mode of the 4th embodiment, to the additional same numeral of the part identical with Figure 28.Mobile controller MCA is with reference to the buffer capacity of 4 reports of handover base station candidate BTS before handover begins, when the stream of 64Kb/s, be judged to be and accommodate, transmit data B to handover base station candidate BTS 1 with the transfer rate coding of 1Mb/s with the transfer rate of 64Kb/s.Thus, mobile terminal MS receives data B with the transfer rate of 64Kb/s, detects the deterioration of the transfer rate of stream, and the two is reduced to 64Kb/s from 1Mb/s to make speed of coding and transfer rate to the streaming server notice.The data that send to mobile controller MCA later are data C shown in Figure 29.

When mobile controller MCA is reduced to 64Kb/s in the transfer rate that detects data C, carry out the multicast transmission to handover base station candidate BTS 2 and BTS 4 in the timing of this detection.As mentioned above, before carrying out handover, make transfer rate reduction, so even be handed over to handover base station candidate BTS 4, mobile terminal MS also can receive the stream of 64Kb/s at the stream of mobile terminal MS to handover base station candidate BTS 4.

As mentioned above, before handover, can realize in the base station of big capacity/high-speed communication, can change QoS in advance adaptively, can behind handover, carry out stream communication reliably thus, and can not cause that grouping abandons.

(E) effect of invention

According to the present invention, the multicast transfer rate when determining Handoff Control according to each handover base station candidate's communication capacity is so can realize effectively utilizing the high speed handover of Internet resources.

According to the present invention, can alleviate the deterioration of the throughput behind the handover. In addition, can provide at once the second best in quality communication. In addition, can increase the message capacity of entire system.

Claims (22)

1. the hand over control method in the mobile communication system, this mobile communication system follows moving of portable terminal to change the Handoff Control of the base station of this communication of mobile terminal, it is characterized in that, and this hand over control method has following steps:

Candidate according to the selected handover base station more than 1 of communications status;

According to communication capacity, under each handover base station candidate's transmission condition, transmit identical communication data to each handover base station candidate; And

From the handover base station candidate that is confirmed as the handover base station communication data of described transmission is sent to portable terminal.

2. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, described communication capacity is the buffer capacity of the buffer that has separately of described handover base station candidate more than 1, determine the transfer rate of the described communication data of multicast separately at described handover base station candidate more than 1 according to this buffer capacity, perhaps, minimum transfer rate among the described handover base station candidate more than 1 is made as public transfer rate, described communication data is carried out multicast to each handover base station candidate with this transfer rate.

3. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, described communication capacity is the user mode of described handover base station candidate Radio Resource separately more than 1, at the transfer rate that described handover base station candidate more than 1 determines the described communication data of multicast separately, described communication data is carried out multicast to each handover base station candidate according to the user mode of this Radio Resource with this transfer rate.

4. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, described communication capacity is described handover base station candidate more than 1 enforceable QoS (service quality) separately, at the transfer rate that described handover base station candidate more than 1 determines the described communication data of multicast separately, described communication data is carried out multicast to each handover base station candidate according to this enforceable QoS with this transfer rate.

5. hand over control method according to claim 1 is characterized in that, in the mobile controller on upper strata, base station, perhaps, with communication of mobile terminal in the base station in carry out described each handle.

6. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, by described each handover base station candidate is inquired about the communication capacity that described communication capacity obtains each handover base station candidate.

7. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, at each preservation of each handover base station candidate and from the communication data speed of network input and the corresponding data of difference of multicast speed.

8. hand over control method according to claim 1 is characterized in that, transmits in the step of identical communication data to each handover base station candidate described, for the grouping of distinguishing multicast and common grouping, to the multicastapackets attach identifier.

9. hand over control method according to claim 1, it is characterized in that, transmit in the step of identical communication data to each handover base station candidate described, variation to described handover base station candidate communication capacity separately more than 1 in the multicast way of transmitting described identical communication data detects, change the transfer rate of the handover base station candidate's who changes at communication capacity multicast adaptively according to this communication capacity after changing, with this transfer rate described communication data is carried out multicast to this handover base station candidate, perhaps from the transmission destination of multicast, remove the handover base station candidate of communication capacity variation and stop multicast.

10. hand over control method according to claim 9 is characterized in that, when removing described handover base station candidate from the transmission destination of multicast, notice abandons the additional grouping that the identifier that multicastapackets uses is arranged.

11. hand over control method according to claim 10 is characterized in that, described handover base station candidate abandons the additional grouping that described identifier is arranged after receiving the grouping discard notification.

12. the mobile controller in the mobile communication system, this mobile communication system follows moving of portable terminal to change the Handoff Control of the base station of this communication of mobile terminal, it is characterized in that, this mobile controller has:

Handover base station candidate's determination portion, it is according to the candidate of the selected handover base station more than 1 of communications status;

Transport unit, it transmits identical communication data to each handover base station candidate according to communication capacity under each handover base station candidate's transmission condition; And

Handover base station determination portion, it is defined as the handover base station with described handover base station candidate more than 1.

13. mobile controller according to claim 12, it is characterized in that, the data that described each handover base station candidate preserves institute's multicast, and the handover base station candidate who is confirmed as the handover base station sends the communication data of being preserved to portable terminal.

14. mobile controller according to claim 12, it is characterized in that, described transport unit is considered as described communication capacity with the buffer capacity of the buffer that described handover base station candidate more than 1 has separately, determine the transfer rate of the described communication data of multicast separately at described handover base station candidate more than 1 according to this buffer capacity, perhaps, minimum transfer rate among the described handover base station candidate more than 1 is defined as public multicast transfer rate, described communication data is carried out multicast to each handover base station candidate with this transfer rate.

15. mobile controller according to claim 12, it is characterized in that, described transport unit is considered as described communication capacity with the user mode of described handover base station candidate Radio Resource separately more than 1, at the transfer rate that described handover base station candidate more than 1 determines the described communication data of multicast separately, described communication data is carried out multicast to each handover base station candidate according to the user mode of this Radio Resource with this transfer rate.

16. mobile controller according to claim 12, it is characterized in that, described transport unit is considered as described communication capacity with described handover base station candidate more than 1 enforceable QoS (service quality) separately, at the transfer rate that described handover base station candidate more than 1 determines the described communication data of multicast separately, described communication data is carried out multicast to each handover base station candidate according to this QoS with this transfer rate.

17. mobile controller according to claim 12 is characterized in that, described transport unit is by inquiring about the communication capacity that described communication capacity obtains each handover base station candidate to described each handover base station candidate.

18. mobile controller according to claim 12 is characterized in that,

Described transport unit has:

The transfer rate determination portion, it determines the transfer rate of the described communication data of multicast according to each handover base station candidate's communication capacity; And

The transfer rate adjustment part, its with described definite transfer rate to described handover base station candidate more than 1 the described communication data of multicast separately,

This transfer rate adjustment part has buffer, and this buffer is at each preservation of described handover base station candidate more than 1 and from the communication data speed of network input and the corresponding data of difference of described multicast speed.

19. mobile controller according to claim 12 is characterized in that, described transport unit is for the grouping of distinguishing multicast and common grouping, to the multicastapackets attach identifier.

20. mobile controller according to claim 12, it is characterized in that, when described transport unit detects the variation of the communication capacity among the described handover base station candidate in the multicast way, change transfer rate adaptively according to this communication capacity after changing, perhaps from the transmission destination of multicast, remove described handover base station candidate and stop multicast at described handover base station candidate's multicast.

21. mobile controller according to claim 20 is characterized in that, described transport unit is when removing described handover base station candidate from the transmission destination of multicast, and notice abandons the additional grouping that the identifier that multicastapackets uses is arranged.

22. a mobile communication system, it has portable terminal and follows moving of this portable terminal to change the mobile controller of Handoff Control of the base station of this communication of mobile terminal, it is characterized in that,

Described mobile controller has:

Handover base station candidate's determination portion, it is according to the candidate of the selected handover base station more than 1 of communications status;

Transport unit, it transmits identical communication data to each handover base station candidate according to communication capacity under each handover base station candidate's transmission condition; And

Handover base station determination portion, it is defined as the handover base station with described handover base station candidate more than 1,

Described portable terminal has receiver, and this receiver receives the described communication data that sends from the described handover base station candidate who is defined as the handover base station.

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