HK1136447A

HK1136447A - Multi-cell coordination for multimedia broadcast multicast services in a wireless communication system

Info

Publication number: HK1136447A
Application number: HK10102875.4A
Authority: HK
Inventors: 陆广; 张国栋; A‧钱德拉
Original assignee: Interdigital Technology Corporation
Priority date: 2006-08-21
Filing date: 2007-08-09
Publication date: 2010-06-25

Description

Multi-cell coordination for multimedia broadcast multicast services in a wireless communication system

Technical Field

The present invention relates to a wireless communication system. More particularly, the present invention relates to multi-cell coordination for Multimedia Broadcast Multicast Services (MBMS) in a wireless communication system.

Background

The third generation partnership project (3GPP), release six, defines MBMS as a corresponding service to other multicast services operating in other communication standards, such as digital video broadcasting-handheld (DVB-H). MBMS allows downlink data to be transmitted from a single source to multiple recipients in broadcast or multicast mode. The existing 3GPP release also defines MBMS channels, scheduling, bearers, procedures, and similar concepts.

In the 3GPP Long Term Evolution (LTE) project, a new universal mobile telecommunications system (UTMS) evolved universal terrestrial radio access network (E-UTRAN) and evolved core network are introduced. This inevitably requires current specification updates for MBMS, thereby enabling the new architecture to efficiently support MBMS.

LTE requires support for single and multi-cell MBMS transmissions. For multi-cell transmission, MBMS (e.g., mobile television) is transmitted over the coverage area of a group of cells, MBMS may be transmitted in a Multicast Channel (MCH), soft combining of MBMS data in a receiver may be supported in a particular service group (i.e., Single Frequency Network (SFN)), and synchronous transmission of MBMS data from multiple cells may also occur.

To achieve synchronous data transmission in multiple cells in an LTE architecture, inter-cell scheduling is required. In a sixth release, synchronization is performed by a Radio Network Controller (RNC). However, if the RNC is absent in the new LTE architecture, the multi-cellular transmission must be achieved by providing another procedure.

Disclosure of Invention

The present invention relates to a method and system for multi-cell coordination for MBMS in a wireless communication system. An MBMS coordination unit is provided to coordinate a plurality of evolved node bs (enodebs) (i.e., cells) for synchronized transmission of MBMS data in multiple cells. The MBMS coordination unit may be located in an access gateway or eNodeB. The MBMS multi-cell scheduling scheme may be pre-configured for enodebs for synchronization. Alternatively, the enodebs may also be dynamically synchronized.

Drawings

The invention will be understood in more detail from the following description of preferred embodiments, given by way of example and to be understood in conjunction with the accompanying drawings, in which:

fig. 1 shows an MBMS coordination unit located in an access gateway according to the present invention;

fig. 2 shows an MBMS coordination unit located in an eNodeB according to the present invention;

FIG. 3 shows a signal flow diagram for pre-configuring a schedule to synchronize a set of eNodeBs, according to one embodiment of the invention;

FIG. 4 shows a signal flow diagram for handshake scheduling to dynamically synchronize a set of eNodeBs, according to another embodiment of the invention;

figure 5 illustrates MBMS Control Channel (MCCH) information scheduling according to the present invention;

FIG. 6 shows an example configuration of an eNodeB operating in accordance with the invention; and

fig. 7 shows an exemplary configuration of an MBMS multi-cell coordination unit operating in accordance with the present invention.

Detailed Description

When referred to hereafter, the terminology "wireless transmit/receive unit (WTRU)" includes but is not limited to a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a Personal Digital Assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. The term "base station" as referred to below includes, but is not limited to, an eNodeB, a site controller, an Access Point (AP), or any other type of interfacing device capable of operating in a wireless environment.

The present invention solves the problem of supporting the implementation of MBMS multi-cell transmission in the proposed LTE architecture. The present invention defines the multi-cell coordination unit and proposes the location of the MBMS coordination unit and different scheduling procedures and defines how to modify the functionality (e.g. notification and calculation) of the existing MBMS in the new architecture and also defines the new scheduling method for the MBMS control channel.

FIG. 1 shows a schematic diagram of a system with multiple eNodeBs (i.e., cells) 105₁、105₂、105₃And 105₄An access gateway 100 in communication. The access gateway 100 includes an MBMS multi-cell coordination unit 110 (i.e., MBMS server) configured in accordance with the present invention. The MBMS multi-cell coordination unit 110 is a logical entity that controls the enodebs 105 and coordinates multi-cell scheduling and transmission when the enodebs 105 belong to the same cell group. The functions of the MBMS coordination unit 110 may include scheduling and timing control, calculation, eNodeB registration and feedback. For each SFN, the MBMS multi-cell coordination unit 110 also configures a common scrambling code for each eNodeB 105 in the SFN. The SFN may also be different (consisting of different cells/enodebs) for different MBMS.

Still referring to fig. 1, the MBMS multi-cell coordination unit 110 includes at least one control portion 115, the control portion 115 being located in a control plane 120 of the access gateway 100 for coordinating control signaling, and the MBMS multi-cell coordination unit 110 further includes at least one data portion 125, the data portion 125 being located in a user plane 130 of the access gateway 100 for coordinating data signaling. The control portion 115 and data portion 125 may have multiple instances, each instance corresponding to a particular service group (i.e., SFN). The access gateway 100 also includes a System Architecture Evolution (SAE) bearer control unit 135, a Mobility Management Entity (MME)140, and a Packet Data Convergence Protocol (PDCP) unit 145.

The SAE bearer control unit 135 is an LTE counterpart to the old "radio access bearer control" or "RAB control" in Wideband Code Division Multiple Access (WCDMA). The SAE bearer control unit 135 controls the configuration of radio access bearers. MME unit 140 is responsible for the following functions: allocation of paging messages to enodebs, security control, idle state mobility control, and ciphering and integrity protection of non-access stratum (NAS) signaling. The major services and functions of the PDCP unit 145 include header compression and decompression, transmission of user data (i.e., PDCP receiving PDCP Service Data Units (SDUs) from NAS and forwarding to Radio Link Control (RLC) layer for delivery and vice versa, reordering of downlink RLC SDUs at least during inter-eNodeB mobility, in-order delivery of upper Protocol Data Units (PDUs) in Handover (HO) in uplink (to be studied next (FFS)), duplicate probing of lower SDUs, and ciphering of user plane data and control plane data (NAS signaling)).

The MBMS multi-cell coordination unit 110 may be located between the E-UTRAN (i.e., eNodeB) and the access gateway 100. The physical location of the MBMS multi-cell coordination unit 110 depends on the particular implementation. As described above, fig. 1 shows an MBMS multi-cell coordination unit 110 co-located with an access gateway 100. In this case there are multiple instances in the control plane 120 of the access gateway 100 for control signaling and multiple instances in the user plane 130 of the access gateway 100 for data transmission.

When there is a hybrid MBMS between LTE and current UMTS systems, the inter-access MBMS coordination unit needs to be placed on the inter-access anchor. The inter-access MBMS coordination unit interacts with the MBMS multi-cell coordination unit 110 at the access gateway 100 for LTE and MBMS functions in the RNC of the UMTS.

In an alternative embodiment, the MBMS multi-cell coordination unit 110 may be located in the eNodeB, as shown in fig. 2. This solution may present some potential problems, such as how to determine which eNodeB is the "master" eNodeB containing the MBMS multi-cell coordination unit 110. The "master" eNodeB may be statically or dynamically determined through pre-configuration so that the "master" eNodeB may change for different services. Also, additional "handshake" signaling is required between enodebs.

When the MBMS data arrives at the access gateway 100, it is scheduled so that it is transmitted synchronously to all enodebs 105 in a particular cell group. According to the present invention, the enodebs 105 perform the actual scheduling when the MBMS multi-cell coordination unit 110 ensures that the transmissions are synchronized between the enodebs. It is assumed that enodebs operate synchronously with respect to time.

Fig. 3 shows a signal flow diagram for implementing a pre-configured scheduling procedure 300 to synchronize a group of enodebs in a wireless communication system including a plurality of WTRUs 305, a plurality of enodebs 310, an MBMS multi-cell coordination unit 315, an operations, administration and maintenance (OAM) system 320, and an access gateway 325, in accordance with one embodiment of the present invention. In step 330, the MBMS multi-cell coordination unit 315 obtains the MBMS multi-cell scheduling criteria, e.g., from the OAM system 320, prior to MBMS start-up. For example, the standard may be an eNodeB that transmits MBMS data within a predetermined certain time after MBMS data notification. Alternatively, the scheme can be used for the eNodeB to transmit MBMS data within a predetermined certain time after the MBMS data first arrives at the eNodeB 310. Each scheme may be set by signaling and triggered by transmission criteria, e.g., by the arrival of MBMS data.

Still referring to fig. 3, before MBMS start (step 335), the eNodeB 310 registers with the MBMS multi-cell coordination unit 315. The registration may be part of a system start/restart procedure in the eNodeB, so that an eNodeB that wants to provide a particular MBMS service needs to register first with the MBMS coordination unit 315. If there is no indication of resource reservation from the MBMS multi-cell coordination unit 315, the eNodeB 310 will inform the MBMS multi-cell coordination unit 315 that resources are available. The MBMS transmission time stamp and information about the resources required for the MBMS data will be communicated to the eNodeB 310. The scheme may be restarted or modified during the MBMS service.

Still referring to fig. 3, after the eNodeB 310 registers with the MBMS multi-cell coordination unit 315, the MBMS multi-cell coordination unit 315 will inform the eNodeB 310 of specific information about one specific MBMS scheduling scheme (step 340). The MBMS scheduling scheme notification may contain information including MBMS service type, data rate, start time, end time, etc. When the MBMS service is started in step 345, MBMS data arrives from the access gateway 325 to the eNodeB 310 (step 350). Finally, in step 355, the eNodeB 310 transmits the MBMS data to the WTRU 305 according to the MBMS scheduling scheme notified in step 340.

Fig. 4 shows a signal flow diagram for implementing a handshake scheduling procedure 400 to dynamically synchronize a set of enodebs in accordance with another embodiment of the present invention, the wireless communication system includes a plurality of WTRUs 405, a plurality of enodebs 410, an MBMS multi-cell coordination unit 415, and an access gateway 420. Each eNodeB 410 is controlled by an MBMS multi-cell coordination unit 415. In step 425, the access gateway 420 (or MBMS multi-cell coordination unit 415) notifies the eNodeB 410 of the MBMS session start message. In step 430, each eNodeB 410 transmits the expected timestamp and resource availability information to the MBMS multi-cell coordination unit 415. The time stamp indicates the time at which each eNodeB 410 can initiate an MBMS transmission. Based on the received information, the MBMS multi-cell coordination unit 415 determines the coordination time at which MBMS data should be transmitted to WTRUs by all enodebs 410 in the same SFN. In step 435, the MBMS multi-cell coordination unit 415 will inform the eNodeB 410 when the transmission of MBMS data to the WTRU should be initiated by transmitting a coordinated scheduling timestamp. Then, the MBMS service is started in step 440. In step 445, the eNodeB 410 receives MBMS data from the access gateway 420. In step 450, the eNodeB 410 provisions the MBMS by transmitting MBMS data to the WTRU405 according to the coordinated scheduling timestamp sent by the MBMS multi-cell coordination unit 415. The handshake signaling described above may need to be retransmitted, and thus, in step 455, the MBMS continues to be performed, and steps 460, 465 and 470 are all implemented in the same manner as corresponding steps 430, 435 and 450, respectively.

According to another embodiment of the present invention, it is important that the MBMS multi-cell coordination unit 110 in fig. 1 receives enough information from the eNodeB 105 so that the MBMS multi-cell coordination unit 110 can schedule the transmission. The MBMS multi-cell coordination unit 110 may have, but is not limited to, the following information:

(1) eNodeB identification: the MBMS multi-cell coordination unit may use the eNodeB identification to detect whether the eNodeB 105 has registered for the service or to obtain other pre-loaded information about the eNodeB 105, such as a previous calculation record, etc.;

(2) eNodeB type: information such as whether the eNodeB 105 controls the hybrid or dedicated cell for MBMS;

(3) the number of users interested in MBMS;

(4) eNodeB status for MBMS (e.g., whether resources can be allocated for MBMS); and

(5) the existing MBMS: when there are multiple MBMS in one cell.

The above information is transmitted from the eNodeB 105 to the MBMS multi-cell coordination unit 110 by control signaling between the eNodeB 105 and the MBMS multi-cell coordination unit 110.

The MBMS multi-cell coordination unit 110 keeps track of the resources available at any particular time. If the resources are not used, the eNodeB 105 is allowed to use it for dedicated services. However, the resource priority should belong to MBMS.

In accordance with another embodiment of the present invention, an MBMS notification mechanism is used to notify WTRUs of an impending change in critical MBMS Control Channel (MCCH) information. An MBMS notification indication is transmitted from an eNodeB to a plurality of WTRUs. However, the notification message may be generated at the access gateway or the MBMS multi-cell coordination unit. If there is no MBMS Indication Channel (MICH), the information is transmitted through the MCCH. If an RRC connection is required, the WTRU should be notified. An idle WTRU or connected mode RRC receives the MBMS notification. Upon detecting the MBMS notification indication for a service group, those WTRUs interested in the service corresponding to the group service start reading the MCCH at the beginning of the next modification period. When a feedback mechanism is employed, the type of feedback information should be included, e.g., computation, channel quality, completion of service, etc.

In the sixth release, the notification is an RRC operation performed by the RNC. In the LTE architecture, the notification function may be performed on the eNodeB. However, for enodebs belonging to the same service group and in the same SFN, the notification should be synchronized by the MBMS multi-cell coordination unit.

In accordance with another embodiment of the present invention, the WTRU uses an MBMS calculation procedure to inform the E-UTRAN of the number of WTRUs interested in receiving MBMS. A calculation request is indicated in the notification and is obtained by requesting WTRUs belonging to the same MBMS service group to respond to the calculation request. The exact number of WTRUs responding to a calculation request is a Radio Resource Management (RRM) problem.

WTRUs with different LTE states react as follows: the WTRU in LTE _ IDLE state requests an RRC connection setup procedure. The WTRU will maintain the RRC connected state until the WTRU receives the MBMS. A WTRU in LTE _ ACTIVE state will only need to inform the E-UTRAN of its interest in MBMS. Within the WTRU, the MBMS-interested response will "lock" any attempt to release the RRC connection or transition the WTRU state from LTE _ ACTIVE to LTE _ IDLE.

In a sixth release, upon receiving MBMS access information (MBMS access information), the WTRU extracts the random number and decides whether or not to respond to the calculation procedure. If the WTRU does not respond in this time period, the WTRU continues to acquire MBMS ACCESSION and repeats the above steps again.

The present invention provides a modification to the process. Upon receiving the calculation indication signal, the LTE-enabled WTRU always notifies the E-UTRAN of the public MBMS in which it is interested. Thus, the E-UTRAN knows immediately how many WTRUs are interested in receiving the MSMS, and this information can also be passed on to the core network and broadcast multicast service center (BM-SC). The WTRU may also inform the E-UTRAN of its current connection status.

Then, for the idle WTRU, the WTRU performs random extraction to determine when to establish the RRC connection. Random extraction will stagger the RRC connection procedure in one cell to prevent overloading. This information can also be transmitted to the E-UTRAN so that the E-UTRAN can know when MBMS should be started.

The present invention provides a method for improved uplink access and resource allocation for a computational process according to another embodiment of the present invention. The calculation is performed in two steps. The first step is to compute the WTRU in LTE _ active state. If the number of WTRUs in LTE _ Acitve mode is not sufficient, then the WTRU in LTE _ Idle mode is calculated. The advantage of this scheme is that when there is a WTRU in connected mode responding, a WTRU in LTE _ Idle mode does not need to transmit its interest for a certain MBMS service. This will save the uplink resources (and/or downlink resources) needed to support the calculation of WTRUs in LTE _ Idle state.

The method for achieving the purpose is as follows:

(1) the MBMS service notification packet indicates that only LTE _ active WTRUs need to respond to the calculation.

(2) Optionally: the computed parameters (e.g., the probability of a response) are changed so that the probability of the WTRU returning a response increases.

(3) The MBMS service notification packet should indicate that the LTE _ Active mode WTRU needs a response calculation if the number of LTE _ Active mode WTRUs returning a response service is not sufficient.

According to another embodiment of the invention, in LTE systems, two logical channels are proposed for MBMS. The MCCH is used for control information and the MBMS Traffic Channel (MTCH) is used for traffic. In LTE, MCCH is the only logical channel to handle MBMS control information. The previous notification transmitted on the MBMS Indication Channel (MICH) and the scheduling information on the MBMS Scheduling Channel (MSCH) may be transmitted through the MCCH.

Figure 5 illustrates MCCH information scheduling according to the present invention. The MCCH information scheduling is based on the current scheduling updated in the sixth release. According to the present invention, the eNodeB sends MBMS notification information to the WTRU via MCCH during the notification period 505, so that the eNodeB can notify the WTRU that MBMS data will be provided in an uplink frame. The eNodeB may send the MBMS notification information to the WTRU a predetermined number of times. After the notification period 505, MBMS control information may be transmitted through the MCCH. The scheduling information previously transmitted through the MSCH may be updated at the notification period 505 by transmitting "change information". Following the notification period 505, a first modification period 501 is initiated. The MCCH information transmitted in the first modification period 501 contains more detailed information on the MBMS including an MBMS service type, an index (index) of a subframe (or TTI) in which a specific MBMS service is transmitted, a Radio Bearer (RB) configuration of the MBMS, and the like. Another modification period 515 occurs after the first modification period 501. In the repetition period 520, non-MBMS access information is periodically transmitted. Each repetition period is shorter than the modification period.

Fig. 6 shows an example configuration of an eNodeB 600 operating in accordance with the present invention. eNodeB 600 includes a receiver 605, a transmitter 610, a processor 615, and an antenna 620. Receiver 605 is configured to receive notification through antenna 620 that an MBMS session has started. The transmitter 610 is configured to transmit the timestamp and resource availability information determined by the processor 615 through the antenna 620 in response to receiving the notification with the receiver 605. The expected timestamp indicates the time when the eNodeB 600 can start MBMS transmission. The receiver 605 is further configured to receive, via the antenna 620, a coordinated scheduling timestamp indicating a coordinated time at which the eNodeB 600 should transmit MBMS data to at least one WTRU at the same SFN. The receiver 605 is further configured to receive MBMS data and the transmitter 610 is further configured to transmit the MBMS data to at least one WTRU according to the coordinated scheduling timestamp. The transmitter 610 is further configured to transmit registration information via the antenna 620 and the receiver 605 is further configured to receive details of the particular MBMS scheduling scheme via the antenna 620.

Fig. 7 shows an example configuration of an MBMS multi-cell coordination unit 700 operating in accordance with the present invention. The MBMS multi-cell coordination unit 700 includes a receiver 705, a transmitter 710, a processor 715 and an antenna 720. The receiver 705 is configured to receive, via the antenna 720, a timestamp and resource availability information indicating a time at which the eNodeB may initiate an MBMS transmission. Under the control of the processor 715, the transmitter 710 is configured to transmit a coordinated scheduling timestamp through the antenna 720 indicating a coordinated time at which the eNodeB should transmit MBMS data to at least one WTRU at the same SFN. The receiver 705 is further configured to receive registration information transmitted by at least one eNodeB via the antenna 720, and the transmitter 710 is further configured to transmit details of the specific MBMS scheduling scheme to the registered eNodeB via the antenna 720. The receiver 705 is also configured to receive a scheduling scheme from the OAM system.

Examples

1. In a wireless communication system including a plurality of wireless transmit/receive units (WTRUs) and a plurality of evolved node bs (enodebs), wherein the enodebs provide MBMS to the WTRUs synchronously, a method for coordinating provision of Multimedia Broadcast Multicast Services (MBMS), the method comprising:

an MBMS coordination unit is provided for coordinating the transmission of MBMS to WTRUs through an eNodeB.

2. The method of embodiment 1, further comprising:

the eNodeB registers to the MBMS coordination unit;

the MBMS coordination unit providing information to registered enodebs to schedule transmission of MBMS data;

the eNodeB receives MBMS data; and

the eNodeB transmits the MBMS data to the WTRU according to scheduling information.

3. The method as in any one of embodiments 1 and 2, wherein the MBMS coordination unit is located in an access gateway.

4. The method as in any one of embodiments 1 and 2 wherein the MBMS coordination unit is located in an eNodeB.

5. The method of any of embodiments 1-4 wherein a first subset of the eNodeBs belongs to a first Single Frequency Network (SFN) and a second subset of the eNodeBs belongs to a second SFN.

6. The method of embodiment 5 wherein at least one eNodeB belongs to both the first and second SFNs.

7. The method as in any one of embodiments 1-6 wherein the MBMS coordination unit comprises at least one control portion located in a control plane of an access gateway for coordinating control signaling and the MBMS coordination unit comprises at least one data portion located in a user plane of an access gateway for coordinating data signaling.

8. The method of embodiment 7 wherein the control portion and data portion each have a plurality of instances, each instance corresponding to a particular Single Frequency Network (SFN).

9. The method as in any one of embodiments 1-8, further comprising:

providing eNodeB identification information to the MBMS coordination unit.

10. The method as in any one of embodiments 1-9, further comprising:

providing eNodeB type information to the MBMS coordination unit.

11. The method as in any one of embodiments 1-10, further comprising:

providing information to the MBMS coordination unit based on the number of WTRU users interested in receiving MBMS data.

12. The method as in any one of embodiments 1-11, further comprising:

providing eNodeB state information for MBMS to the MBMS coordination unit.

13. The method as in any one of embodiments 1-12, further comprising:

the existing MBMS information is provided to the MBMS coordination unit.

14. In a wireless communication system including a plurality of wireless transmit/receive units (WTRUs) and a plurality of evolved node bs (enodebs), wherein the enodebs provide MBMS to the WTRUs synchronously, a method for coordinating provision of Multimedia Broadcast Multicast Services (MBMS), the method comprising:

providing an MBMS coordination unit;

the eNodeB receives a notification that an MBMS session has been started;

each eNodeB sending a timestamp and resource availability information to the MBMS coordination unit, the expected timestamp indicating a time at which the eNodeB can start MBMS transmission;

the eNodeB receiving a coordinated scheduling timestamp generated by the MBMS coordination unit indicating a coordinated time at which the eNodeB should transmit MBMS data to the WTRUs in the same Single Frequency Network (SFN);

the eNodeB receives the MBMS data; and

the eNodeB transmits the MBMS data to the WTRU according to the coordinated scheduling timestamp.

15. The method of embodiment 14 wherein the MBMS coordination unit is located in an access gateway.

16. The method of embodiment 14 wherein the MBMS coordination unit is located in an eNodeB.

17. A method as in any of embodiments 14-16 wherein a first subset of the eNodeBs belongs to a first SFN and a second subset of the eNodeBs belongs to a second SFN.

18. The method of embodiment 17 wherein at least one eNodeB belongs to both the first and second SFNs.

19. The method as in any one of embodiments 14-18 wherein the MBMS coordination unit comprises at least one control portion located in a control plane of an access gateway for coordinating control signaling and the MBMS coordination unit comprises at least one data portion located in a user plane of an access gateway for coordinating data signaling.

20. The method of embodiment 19 wherein the control portion and data portion each have multiple instances, each instance corresponding to a particular SFN.

21. A method as in any of embodiments 14-20 wherein the eNodeB receives the MBMS data from an access gateway.

22. A wireless communication system for coordinating Multimedia Broadcast Multicast Service (MBMS) provisioning, the system comprising:

an MBMS coordination unit;

a plurality of wireless transmit/receive units (WTRUs); and

a plurality of evolved node Bs (eNodeBs), wherein each eNodeB is configured to (i) register with the MBMS coordination unit, (ii) receive information from the MBMS coordination unit to schedule transmission of MBMS data, (iii) receive MBMS data, and (iv) transmit the MBMS data to a WTRU according to the scheduling information.

23. The system of embodiment 22 wherein the MBMS coordination unit is located in an access gateway.

24. The system of embodiment 22 wherein the MBMS coordination unit is located in an eNodeB.

25. The system as in any of embodiments 22-24 wherein a first subset of the enodebs belongs to a first Single Frequency Network (SFN) and a second subset of the enodebs belongs to a second SFN.

26. The system of embodiment 25 wherein at least one eNodeB belongs to both the first and second SFNs.

27. The system as in any one of embodiments 22-26 wherein the MBMS coordination unit comprises at least one control portion in a control plane of an access gateway for coordinating control signaling and the MBMS coordination unit comprises at least one data portion in a user plane of an access gateway for coordinating data signaling.

28. The system of embodiment 27 wherein the control portion and data portion each have a plurality of instances, each instance corresponding to a particular Single Frequency Network (SFN).

29. The system as in any one of embodiments 22-28, further comprising:

an access gateway configured to provide MBMS data to an eNodeB for transmission to a WTRU; and

an operation, administration and maintenance (OAM) system configured to provide MBMS multi-cell scheduling criteria to the MBMS coordination unit.

30. A wireless communication system for coordinating Multimedia Broadcast Multicast Service (MBMS) provisioning, the system comprising:

an MBMS coordination unit;

a plurality of wireless transmit/receive units (WTRUs); and

a plurality of evolved node bs (enodebs), wherein each eNodeB is configured to (i) receive a notification that an MBMS session has been initiated and send a timestamp and resource availability information to an MBMS coordination unit, the expected timestamp indicating a time at which the eNodeB may initiate MBMS transmissions, (ii) receive a coordinated scheduling timestamp generated by the MBMS coordination unit indicating a coordinated time at which the eNodeB should transmit MBMS data to a WTRU in the same Single Frequency Network (SFN), (iii) receive MBMS data, and (iv) transmit the MBMS data to the WTRU in accordance with the coordinated scheduling timestamp.

31. The system of embodiment 30 wherein the MBMS coordination unit is located in an access gateway.

32. The system of embodiment 30 wherein the MBMS coordination unit is located in an eNodeB.

33. The system as in any one of embodiments 30-32 wherein a first subset of the enodebs belongs to a first SFN and a second subset of the enodebs belongs to a second SFN.

34. The system of embodiment 33 wherein at least one eNodeB belongs to both the first and second SFNs.

35. The system as in any one of embodiments 30-34 wherein the MBMS coordination unit comprises at least one control portion in a control plane of an access gateway for coordinating control signaling and the MBMS coordination unit comprises at least one data portion in a user plane of an access gateway for coordinating data signaling.

36. The system of embodiment 35 wherein the control portion and data portion each have multiple instances, each instance corresponding to a particular SFN.

37. The system as in any one of embodiments 30-36, further comprising:

38. An access gateway for controlling a plurality of evolved node bs, the access gateway comprising:

a control plane;

a user plane; and

a Multimedia Broadcast Multicast Service (MBMS) multi-cell coordination unit comprising at least one control part located in a control plane of an access gateway for coordinating control signaling to be transmitted to enodebs, and at least one data part located in a user plane of the access gateway for coordinating data signaling to be transmitted to the enodebs.

39. The access gateway of embodiment 38, wherein the control portion and data portion each have multiple instances, each instance corresponding to a particular Single Frequency Network (SFN).

40. An access gateway as in any of embodiments 38 and 39, further comprising:

a System Architecture Evolution (SAE) bearer control element;

a Mobility Management Entity (MME); and

a Packet Data Convergence Protocol (PDCP) unit.

41. The access gateway of embodiment 40, wherein the SAE bearer control unit controls configuration of radio access bearers.

42. The access gateway of embodiment 40, wherein the MME unit is responsible for allocation of paging messages to at least one of eNodeBs, security control, idle state mobility control, and ciphering and integrity protection of non-access stratum (NAS) signaling.

43. The access gateway of embodiment 40, wherein the PDCP unit performs header compression and decompression, transmission of user data, duplicate detection of lower layer Service Data Units (SDUs), and ciphering of user plane data and control plane data.

44. An evolved node b (eNodeB), the eNodeB comprising:

a receiver configured to receive a notification that a Multimedia Broadcast Multicast Service (MBMS) session has been initiated; and

a transmitter configured to transmit a timestamp and resource availability information in response to receiving the notification, the expected timestamp indicating a time at which the eNodeB can initiate MBMS delivery.

45. The eNodeB of embodiment 44 wherein the receiver is further configured to receive a coordinated scheduling timestamp indicating a coordinated time at which the eNodeB should transmit MBMS data to at least one wireless transmit/receive unit (WTRU) in the same Single Frequency Network (SFN).

46. The eNodeB of embodiment 45 wherein the receiver is further configured to receive MBMS data and the transmitter is further configured to transmit the MBMS data to the at least one WTRU according to a coordinated scheduling timestamp.

47. The eNodeB of embodiment 44 wherein the transmitter is further configured to transmit registration information and the receiver is further configured to receive details of a particular MBMS scheduling scheme.

48. A Multimedia Broadcast Multicast Service (MBMS) multi-cell coordination unit, comprising:

a receiver configured to receive a timestamp and resource availability information indicating a time at which an evolved node B (eNodeB) initiated an MBMS transmission; and

a transmitter configured to transmit a coordinated scheduling timestamp indicating a coordinated time at which the eNodeBs should transmit MBMS data to at least one wireless transmit/receive unit (WTRU) in the same Single Frequency Network (SFN).

49. The MBMS multi-cell coordination unit of embodiment 48, wherein the receiver is further configured to receive registration information transmitted by at least one eNodeB, and the transmitter is further configured to transmit details of the specific MBMS scheduling scheme to the registered enodebs.

50. The MBMS multi-cell coordination unit of embodiment 49, wherein the receiver is further configured to receive the scheduling scheme from an operations, administration, and maintenance (OAM) system.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium, examples of which include Read Only Memory (ROM), Random Access Memory (RAM), registers, buffer memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs), for execution by a general purpose computer or a processor.

For example, suitable processors include: a general-purpose processor, a special-purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any Integrated Circuit (IC), and/or a state machine.

A processor in association with software may be used to implement a radio frequency transceiver for use in a Wireless Transmit Receive Unit (WTRU), user equipment, terminal, base station, radio network controller, or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a video circuit, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, bluetoothA module, a Frequency Modulation (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and/or any Wireless Local Area Network (WLAN) module.

Claims

providing an MBMS coordination unit;

the eNodeB registers to the MBMS coordination unit;

the MBMS coordination unit providing information to registered enodebs to schedule transmission of MBMS data; and

the eNodeB receives MBMS data; and

2. The method of claim 1, wherein the MBMS coordination unit is located in an access gateway.

3. The method of claim 1, wherein the MBMS coordination unit is located in an eNodeB.

4. The method of claim 1 wherein a first subset of the enodebs belongs to a first Single Frequency Network (SFN) and a second subset of the enodebs belongs to a second SFN.

5. The method of claim 4, wherein at least one eNodeB belongs to both a first SFN and a second SFN.

6. The method of claim 1, wherein the MBMS coordination unit comprises at least one control part located in a control plane of an access gateway for coordinating control signaling and at least one data part located in a user plane of the access gateway for coordinating data signaling.

7. The method of claim 6, wherein the control portion and the data portion each have a plurality of instances, each instance corresponding to a particular Single Frequency Network (SFN).

8. The method of claim 1, further comprising:

providing eNodeB identification information to the MBMS coordination unit.

9. The method of claim 1, further comprising:

providing eNodeB type information to the MBMS coordination unit.

10. The method of claim 1, further comprising:

11. The method of claim 1, further comprising:

providing eNodeB state information for MBMS to the MBMS coordination unit.

12. The method of claim 1, further comprising:

providing existing MBMS information to the MBMS coordination unit.

13. In a wireless communication system including a plurality of wireless transmit/receive units (WTRUs) and a plurality of evolved node bs (enodebs), wherein the enodebs provide MBMS to the WTRUs synchronously, a method for coordinating provision of Multimedia Broadcast Multicast Services (MBMS), the method comprising:

providing an MBMS coordination unit;

the eNodeB receives a notification that an MBMS session has been started;

each eNodeB transmitting a time stamp and resource availability information to the MBMS coordination unit, the projected time stamp indicating when the eNodeB can initiate MBMS delivery;

the eNodeB receives the MBMS data; and

14. The method of claim 13, wherein the MBMS coordination unit is located in an access gateway.

15. The method of claim 13 wherein the MBMS coordination unit is located in an eNodeB.

16. The method of claim 13 wherein a first subset of the enodebs belongs to a first SFN and a second subset of the enodebs belongs to a second SFN.

17. The method of claim 16 wherein at least one eNodeB belongs to both the first SFN and the second SFN.

18. The method of claim 13, wherein the MBMS coordination unit comprises at least one control part located in a control plane of an access gateway for coordinating control signaling and at least one data part located in a user plane of the access gateway for coordinating data signaling.

19. The method of claim 18, wherein the control portion and the data portion each have multiple instances, each instance corresponding to a particular SFN.

20. The method of claim 13, wherein the eNodeB receives the MBMS data from the access gateway.

21. A wireless communication system for coordinating Multimedia Broadcast Multicast Service (MBMS) provisioning, the system comprising:

an MBMS coordination unit;

a plurality of wireless transmit/receive units (WTRUs); and

a plurality of evolved node Bs (eNodeBs), wherein each eNodeB is configured to: (i) register with the MBMS coordination unit, (ii) receive information from the MBMS coordination unit to schedule transmission of MBMS data, (iii) receive MBMS data, and (iv) transmit the MBMS data to the WTRU according to the scheduling information.

22. The system of claim 21, wherein the MBMS coordination unit is located in an access gateway.

23. The system of claim 21 wherein the MBMS coordination unit is located in an eNodeB.

24. The system of claim 21 wherein a first subset of the enodebs belongs to a first Single Frequency Network (SFN) and a second subset of the enodebs belongs to a second SFN.

25. The system of claim 24 wherein at least one eNodeB belongs to both the first SFN and the second SFN.

26. The system of claim 21, wherein the MBMS coordination unit comprises at least one control part located in a control plane of an access gateway for coordinating control signaling and at least one data part located in a user plane of the access gateway for coordinating data signaling.

27. The system of claim 26 wherein the control portion and the data portion each have a plurality of instances, each instance corresponding to a particular Single Frequency Network (SFN).

28. The system of claim 21, further comprising:

an access gateway configured to provide the MBMS data to the eNodeB for transmission to the WTRU; and

29. A wireless communication system for coordinating Multimedia Broadcast Multicast Service (MBMS) provisioning, the system comprising:

an MBMS coordination unit;

a plurality of wireless transmit/receive units (WTRUs); and

a plurality of evolved node Bs (eNodeBs), wherein each eNodeB is configured to: (i) receiving a notification that an MBMS session has started and sending a timestamp and resource availability information to the MBMS coordination unit, the expected timestamp indicating a time when the eNodeB can start MBMS transmission, (ii) receiving a coordinated scheduling timestamp generated by the MBMS coordination unit indicating a coordinated time when the eNodeB should transmit MBMS data to the WTRU in the same Single Frequency Network (SFN), (iii) receiving MBMS data, and (iv) transmitting the MBMS data to the WTRU according to the coordinated scheduling timestamp.

30. The system of claim 29, wherein the MBMS coordination unit is located in an access gateway.

31. The system of claim 29 wherein the MBMS coordination unit is located in an eNodeB.

32. The system of claim 29 wherein a first subset of the enodebs belongs to a first SFN and a second subset of the enodebs belongs to a second SFN.

33. The system of claim 29 wherein at least one eNodeB belongs to both the first and second SFNs.

34. The system of claim 29, wherein the MBMS coordination unit comprises at least one control part located in a control plane of the access gateway for coordinating control signaling and at least one data part located in a user plane of the access gateway for coordinating data signaling.

35. The system of claim 34 wherein the control portion and the data portion each have multiple instances, each instance corresponding to a particular SFN.

36. The system of claim 29, further comprising:

37. An access gateway for controlling a plurality of evolved node bs, the access gateway comprising:

a control plane;

a user plane; and

a Multimedia Broadcast Multicast Service (MBMS) multi-cell coordination unit comprising at least one control part located in a control plane of an access gateway for coordinating control signaling to the enodebs and at least one data part located in a user plane of an access gateway for coordinating data signaling to the enodebs.

38. The access gateway of claim 37, wherein the control portion and the data portion each have multiple instances, each instance corresponding to a particular Single Frequency Network (SFN).

39. The access gateway of claim 37, further comprising:

a System Architecture Evolution (SAE) bearer control element;

a Mobility Management Entity (MME); and

a Packet Data Convergence Protocol (PDCP) unit.

40. The access gateway of claim 39, wherein the SAE bearer control unit controls configuration of radio access bearers.

41. The access gateway of claim 39, wherein the MME unit is responsible for allocating paging messages to the eNodeBs, security control, idle state mobility control, and at least one of ciphering and integrity protection of non-access stratum (NAS) signaling.

42. The access gateway of claim 39, wherein the PDCP unit performs header compression and decompression, transmission of user data, duplicate detection of lower layer Service Data Units (SDUs), and ciphering of user plane data and control plane data.

43. An evolved node b (eNodeB), the eNodeB comprising:

44. The eNodeB of claim 43, wherein the receiver is further configured to receive a coordinated scheduling timestamp indicating a coordinated time at which the eNodeB should transmit MBMS data to at least one wireless transmit/receive unit (WTRU) in the same Single Frequency Network (SFN).

45. The eNodeB of claim 44 wherein the receiver is further configured to receive MBMS data and the transmitter is further configured to transmit MBMS data to the at least one WTRU in accordance with the coordinated scheduling timestamp.

46. The eNodeB of claim 43, wherein the transmitter is further configured to transmit registration information and the receiver is further configured to receive details of a particular MBMS scheduling scheme.

47. A Multimedia Broadcast Multicast Service (MBMS) multi-cell coordination unit, the MBMS multi-cell coordination unit comprising:

a receiver configured to receive a timestamp and resource availability information indicating a time at which an evolved node B (eNodeB) is capable of initiating MBMS transmission; and

48. The MBMS multi-cell coordination unit of claim 47, wherein the receiver is further configured to receive registration information transmitted by at least one eNodeB, and the transmitter is further configured to transmit details of a particular MBMS scheduling scheme to the registered enodebs.

49. The MBMS multi-cell coordination unit of claim 48, wherein the receiver is further configured to receive the scheduling scheme from an operations, administration, and maintenance (OAM) system.