HK1142737B - Method and apparatus for sending scheduling information for broadcast and multicast services in a cellular communication system - Google Patents

Description

Method and apparatus for transmitting scheduling information for broadcast and multicast services in a cellular communication system

This application claims priority from U.S. provisional application No.60/940,873 entitled "ascideumulin gsm system-MBMS," filed 30/5/2007, which is assigned to the assignee of the present application and is hereby incorporated by reference.

Technical Field

The present disclosure relates generally to communication, and more specifically to techniques for supporting broadcast and multicast services in a cellular communication system.

Background

A cellular communication system is capable of supporting two-way communication for multiple users by sharing the available system resources. Cellular systems differ from broadcast systems that primarily or exclusively support unidirectional transmission from a broadcast station to a user. Cellular systems are widely deployed to provide various communication services, and may be multiple-access systems such as Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, orthogonal FDMA (ofdma) systems, single-carrier FDMA (SC-FDMA) systems, and the like.

Cellular systems may support broadcast, multicast, and unicast services. A broadcast service is a service that is received by all users, such as a news broadcast. A multicast service is a service that is received by a group of users, for example, a subscription video service. Unicast service is a service intended for a particular user, e.g. a voice call. It is desirable to efficiently support broadcast, multicast and unicast services in a cellular system.

Disclosure of Invention

Techniques for supporting broadcast, multicast, and unicast services in a cellular system are described herein. In one aspect, a node B multiplexes data for broadcast and multicast services with data for unicast services on radio resources available for transmission. The radio resources may include: time, frequency, power, code, and/or other resources that may be used for transmission over the air. The node B may periodically transmit scheduling information that may be used by the user to determine the radio resources carrying the broadcast and multicast services. The scheduling information may convey where the broadcast and multicast services are sent and possibly the manner in which the services are sent.

In one design, a node B may Time Division Multiplex (TDM) data for broadcast and multicast services and data for unicast services. Each broadcast and multicast service may be transmitted in at least one time unit, and the scheduling information may convey the time unit for each broadcast or multicast service. In another design, the node B may map data for broadcast and multicast services to time frequency blocks. The scheduling information may (i) transmit time-frequency blocks for each broadcast or multicast service, or (ii) control information indicating time-frequency blocks that may transmit each service.

The scheduling information may be transmitted in each scheduling period and radio resources for broadcast and multicast services may be transmitted in the current or subsequent scheduling period. The node B may also periodically send a change flag indicating whether the scheduling information will change in the upcoming scheduling period.

Various aspects and features of the disclosure are described in detail below.

Drawings

Fig. 1 shows a cellular communication system.

Fig. 2 shows an exemplary transmission structure.

Fig. 3 shows an exemplary transmission of different services in a multi-cell mode.

Fig. 4 shows an exemplary transmission of different services in single cell mode.

Fig. 5 shows a design of transmitting scheduling information in a multi-cell mode.

Fig. 6 and 7 show two designs for transmitting scheduling information in single cell mode.

Fig. 8 shows a process for transmitting broadcast, multicast and unicast services.

Fig. 9 illustrates an apparatus for transmitting broadcast, multicast and unicast services.

Fig. 10 shows a process for receiving a service.

Fig. 11 shows an apparatus for receiving a service.

Fig. 12 shows a design of sending a change flag for scheduling information.

Fig. 13 shows a process for transmitting scheduling information.

Fig. 14 shows an apparatus for transmitting scheduling information.

Fig. 15 shows a process for receiving scheduling information.

Fig. 16 shows an apparatus for receiving scheduling information.

Fig. 17 shows a block diagram of a node B and a UE.

Detailed Description

The techniques described herein may be used for various cellular communication systems such as CDMA, TDMA, FDMA, OFDMA and SC-FDMA systems. The terms "system" and "network" are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, and so on. UTRA includes wideband CDMA (wcdma) and other variants of CDMA. cdma2000 covers IS-2000, 1S-95 and IS-856 standards. TDMA systems implement wireless technologies such as global system for mobile communications (GSM). OFDMA systems may implement wireless technologies such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11(Wi-Fi), IEEE802.16(WiMAX), IEEE802.20, Flash-And so on. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). The 3GPP Long Term Evolution (LTE) is an upcoming release of UMTS that employs E-UTRA, which uses OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE, and GSM are described in documents of the organization entitled "third Generation partnership project" (3 GPP). Cdma2000 and UMB are described in documents of the organization entitled "third generation partnership project 2" (3GPP 2). For clarity, certain aspects of the techniques herein are described with respect to LTE, so the description below uses LTE terminology mostly.

Fig. 1 shows a cellular communication system 100, which may be an LTE system. System 100 may include multiple node bs and other network entities. For simplicity, only three node bs 110a, 110B, and 110c are shown in fig. 1. A node B may be a fixed station used for communicating with User Equipment (UE) and may also be referred to as an evolved node B (enb), a base station, an access point, etc. Each node B100 provides communication coverage for a particular geographic area 102. To increase system capacity, the entire coverage area of the node B may be divided into a plurality of smaller areas, e.g., three smaller areas 104a, 104B, and 104 c. Each smaller area may be served by a respective node B subsystem. In 3GPP, the term "cell" can refer to the smallest coverage area of a node B and/or a node B subsystem serving this coverage area. In other systems, the term "sector" refers to the smallest coverage area of a base station and/or a base station subsystem serving this coverage area. For clarity, the 3GPP concept of a cell is used in the following description.

In the example shown in fig. 1, each node B110 has three cells covering different geographical areas. For simplicity, the cells shown in fig. 1 do not overlap each other. In practical deployments, adjacent cells typically overlap each other on a border, which allows the UE to receive coverage from one or more cells at any location as it moves through the system.

UEs 120 may be distributed throughout the system, and each UE may be fixed or mobile. The UE may also be referred to as: mobile station, terminal, access terminal, subscriber unit, station, etc. The UE may be: cellular phones, Personal Digital Assistants (PDAs), wireless modems, wireless communication devices, handheld devices, laptop computers, cordless telephones, and the like. A UE may communicate with a node B via transmissions on the downlink and uplink. The downlink (or forward link) is the communication link from the node bs to the UEs, and the uplink (or reverse link) is the communication link from the UEs to the node bs. In fig. 1, a solid line with double arrows indicates bidirectional communication between a node B and a UE. The dashed line with a single arrow indicates that the UE receives downlink signals from the node B, e.g. for broadcast and/or multicast services. The terms "UE" and "user" are used interchangeably herein.

Fig. 2 illustrates an exemplary transmission structure 200 that may be used for the downlink in system 100. The transmission timeline may be divided into units of radio frames. Each radio frame has a predetermined duration (e.g., 10 milliseconds (ms)) and is divided into 10 subframes. Each subframe may include two slots, each of which may include a fixed or configurable number of symbol periods, e.g., six or seven symbol periods.

Orthogonal Frequency Division Multiplexing (OFDM) may be used to divide the system bandwidth into multiple (K) subcarriers. The available time-frequency resources are divided into a plurality of resource blocks. Each resource block may include Q subcarriers in a slot, where Q may be equal to 12 or some other value. The available resource blocks may be used for transmitting data, overhead information, pilots, and so on.

The system may support evolved multimedia broadcast/multicast service (E-MBMS) for a plurality of UEs, as well as unicast service for individual UEs. The service of the E-MBMS may be referred to as an E-MBMS service, and may be a broadcast service or a multicast service.

In LTE, data and overhead information are handled as logical channels of the Radio Link Control (RLC) layer. The logical channels are mapped to transport channels of a Medium Access Control (MAC) layer. The transport channel is mapped to a physical channel of a physical layer (PHY). Table 1 lists some of the logical channels (labeled "L"), transport channels (labeled "T"), and physical channels (labeled "P") used in LTE and provides a short description of each channel.

TABLE 1

Channel with a plurality of channels	Name (R)	Type (B)	Description of the invention
				Dynamic broadcast channel	D-BCH	L	Carrying system information
E-MBMS scheduling channel	MSCH	L	Carrying scheduling information and possibly control information for E-MBMS services
				E-MBMS service channel	MTCH	L	Carrying data for E-MBMS services
E-MBMS control channel	MCCH	L	Carrying configuration information for E-MBMS services
				Multicast channel	MCH	T	Carrying MTCH and MCCH
Downlink shared channel	DL-SCH	T	Carrying MTCH and other logical channels
				Physical broadcast channel	PBCH	P	Carrying underlying system information for use in obtaining a system
Physical multicast channel	PMCH	P	Carry the MCH
				Physical downlink shared channel	PDSCH	P	Carrying data for DL-SCH
Physical downlink control channel	PDCCH	P	Carrying control information for DL-SCH

As shown in table 1, different types of overhead information may be transmitted on different channels. Table 2 lists some types of overhead information and provides a short description of each type. Table 2 also shows the channels on which each type of overhead information may be sent according to one design.

TABLE 2

Overhead information	Channel with a plurality of channels	Description of the invention
			System information	D-BCH and PBCH	Information relating to communicating with and/or receiving data from a system
Scheduling information	MSCH	Information indicating when different services are sent and possibly where and how to send
			Configuration information	MCCH	Information for receiving services, e.g. for bearer configuration such as service set, RLC configuration, lower layer settings, etc.
Control information	PDCCH or MSCH	Information received for data transmission for a service, e.g., resource allocation, modulation and coding scheme, etc.

Different types of overhead information may also be referred to by other names. The scheduling and control information may be dynamic when the system and configuration information is semi-static.

The system may support multiple operational modes of E-MBMS, which may include a multi-cell mode and a single-cell mode. The multi-cell mode has the following features:

the content of a broadcast or multicast service is transmitted simultaneously in a plurality of cells,

the radio resources for broadcast and multicast services are located by an MBMS Coordination Entity (MCE), which may be logically located on a node B,

the content of the broadcast and multicast services is mapped to the MCH of the node B,

time-division multiplexing (e.g., at the subframe level) of data for broadcast, multicast, and unicast services.

The single cell mode may have the following features:

each cell transmits content for broadcast and multicast services, without the need to synchronize with other cells,

radio resources for broadcast and multicast services are allocated by the node B,

the content of the broadcast and multicast service is mapped to the DL-SCH,

the data for broadcast, multicast and unicast services may be multiplexed in any manner allowed by the structure of the DL-SCH.

Generally, the E-MBMS service may be supported by a multi-cell mode, a single-cell mode, and/or other modes. The multi-cell mode may be used for E-MBMS multicast/broadcast single frequency network (MBSFN) transmission, which allows a UE to combine signals received from multiple cells in order to improve reception performance.

Fig. 3 shows an exemplary transmission of E-MBMS and unicast services by M cells 1 to M in a multi-cell mode. For each cell, the horizontal axis represents time and the vertical axis represents frequency. In one design of E-MBMS, which is assumed for most of the following, the transmission timeline for each cell may be divided into time units of multiple subframes. In another design of E-MBMS, the transmission timeline for each cell is divided into time units of other durations. In general, a time cell may correspond to: one subframe, one slot, one symbol period, multiple symbol periods, multiple slots, multiple subframes, etc.

In the example shown in fig. 3, M cells transmit three E-MBMS services 1, 2 and 3. All M cells transmit E-MBMS service 1 in subframes 1 and 3, E-MBMS service 2 in subframe 4, and E-MBMS service 3 in subframes 7 and 8. The M cells transmit the same content for each of the three E-MBMS services. Each cell will send its unicast service in subframes 2, 5, and 6. M cells may send different content for their unicast services.

Fig. 4 shows an exemplary transmission of E-MBMS and unicast services by M cells in single cell mode. For each cell, the horizontal axis represents time and the vertical axis represents frequency. In the example shown in fig. 4, M cells transmit three E-MBMS services 1, 2 and 3. Cell 1 transmits E-MBMS service 1 in two time frequency blocks 410 and 412, E-MBMS service 2 in time frequency block 414 (labeled "S2"), and E-MBMS service 3 in two time frequency blocks 416 and 418. Each remaining cell transmits E-MBMS service 1 in two time-frequency blocks, E-MBMS service 2 in one time-frequency block, and E-MBMS service 3 in two time-frequency blocks.

In general, an E-MBMS service may be transmitted in any number of time-frequency blocks. Each time frequency block may have any size and may cover any number of subcarriers and any number of symbol periods. The size of each time frequency block may depend on the amount of data to be transmitted and possibly other factors. The M cells may transmit three E-MBMS services 1, 2, and 3 in multiple time frequency blocks that are not aligned in time and frequency, as shown in fig. 4. In addition, M cells may transmit the same or different contents of the three E-MBMS services. Each cell may transmit its own unicast service in the remaining time-frequency resources not used for the three E-MBMS services. M cells may send different content for their unicast service.

Fig. 3 and 4 show exemplary designs for transmitting E-MBMS services in multi-cell mode and single-cell mode. The E-MBMS service may also be transmitted in the multi-cell mode and the single-cell mode in other manners, e.g., using Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), other multiplexing schemes, or a combination of any of the above.

In an aspect, scheduling information for an E-MBMS service may be transmitted periodically on a scheduling channel, such as the MSCH. In one design, the MSCH may be mapped to the MCH in multi-cell mode or the MSCH may be mapped to the DL-SCH in single cell mode. MSCH may also be mapped to other transport channels.

In one design, the MSCH may be sent periodically in each scheduling period and may carry scheduling information for receiving the E-MBMS service in that scheduling period. In general, the scheduling period may cover any time period, which may be selected based on various factors such as channel switching speed, battery power storage, and so forth. The UE may change channels in the middle of a scheduling period and may need to wait until the next scheduling period in order to receive the scheduling information for the new channel and then begin receiving data from this channel. A shorter scheduling period may increase channel switching speed. Conversely, a longer scheduling period may reduce the number of times the UE needs to receive or check the MSCH, which can reduce the battery power consumption of the UE. In one design, the scheduling period may be a superframe, which may be 500ms, one second, or other suitable time period. The scheduling period of the multi-cell mode may or may not be equal to the scheduling period of the single-cell mode.

In one design, the MSCH may be sent in the first N subframes of each scheduling period. N may be a fixed value (e.g., specified by a standard) and known a priori by all UEs. Alternatively, N may be a configurable value and carried in system information, which may be sent on the D-BCH or some other channel. The modulation and coding of the MSCH may be fixed (e.g., specified by a standard) or may be configurable (e.g., transmitted on D-BCH).

In one design, the MSCH may be transmitted on all available radio resources in the first N subframes of a scheduling period. The remaining subframes of the scheduling period may carry data and/or other information for broadcast, multicast, and/or unicast services. In another design, the MSCH may be transmitted over a subset of the radio resources in the first N subframes. The radio resources for the MSCH may be communicated in system information or control information, or otherwise made known to the UE. The remaining wireless resources in the scheduling period may be used to transmit data and/or other information for broadcast, multicast, and/or unicast services.

Fig. 5 shows a design of transmitting MSCH in multi-cell mode. In this design, the MSCH is sent in the first N-4 subframe of the scheduling period, and carries scheduling information for all E-MBMS services in the scheduling period. The MSCH also carries scheduling information for MCCH, which can be considered as E-MBMS service on scheduling information. The MCCH may carry configuration information for the E-MBMS service. The configuration information may be semi-static and may convey bearer (bearer) configuration, mapping of service Identifiers (IDs) to logical channel IDs, and/or other parameters (e.g., modulation and coding) of the E-MBMS service.

The scheduling information may be provided in a variety of formats. In one design shown in fig. 5, the scheduling information is subframe-centric and conveys which MBMS service (if any) is transmitted in each subframe of the scheduling period. In the example shown in fig. 5, the scheduling information indicates that subframes 5 and 6 carry MCCH, subframes 7 and 9 carry E-MBMS service 1, subframe 8 carries unicast service, subframe 10 carries E-MBMS service 2, subframes 11 and 12 carry unicast service, subframes 13 and 14 carry E-MBMS service 3, subframes 15 and 16 carry unicast service, etc. The scheduling information may convey subframes for both E-MBMS and unicast services (as shown in fig. 5), or subframes for only E-MBMS services.

In another design, the scheduling information is service centric and conveys which subframe each E-MBMS service uses. In the example shown in fig. 5, the scheduling information may indicate that MCCH is transmitted in subframes 5 and 6, E-MBMS service 1 is transmitted in subframes 7 and 9, E-MBMS service 2 is transmitted in subframe 10, E-MBMS service 3 is transmitted in subframes 13 and 14, and unicast service is transmitted in subframes 8, 11, 12, 15, and 16. The scheduling information may also be transmitted in other manners for the subframes used for the E-MBMS service.

The MSCH may convey the location (or subframe) of the E-MBMS service, as described above. In one design, the MSCH may also carry control information for receiving the E-MBMS service. In this design, no control information is sent in subframes used for the E-MBMS service. In another design, control information for receiving E-MBMS services may be sent in subframes in which those services are sent.

Each E-MBMS service may be associated with one service ID and may be transmitted on one logical channel. The mapping of E-MBMS service IDs to logical channel IDs may be performed by higher layers and provided, for example, in a service guide (guide) or some other higher layer signaling. The service to channel mapping may be sent to the UE in a broadcast or multicast mode. In one design, the scheduling information may transmit subframes for different logical channel IDs. The UE may obtain the service-to-channel mapping, determine logical channel IDs for the E-MBMS service of interest, and determine subframes for the logical channel IDs from the scheduling information. In another design, the scheduling information may transmit subframes for different service IDs without explicitly signaling the intermediate mapping.

In one design, the number of subframes (N), the modulation and coding scheme, and other parameters for the MSCH are known a priori by the UE (e.g., specified in a standard). In this design, the UE may receive the MSCH in each scheduling period based on known information for the MSCH. In another design, the number of subframes, modulation and coding scheme, and/or other parameters for the MSCH may be conveyed in system information sent on the D-BCH. In this design, the UE may first receive system information from the D-BCH, determine relevant information for the MSCH, and receive the MSCH based on this relevant information.

Fig. 6 shows a design for transmitting MSCH in single cell mode. The MSCH may be mapped to the DL-SCH, which may be mapped to the PDSCH. The MSCH may be transmitted in the first N subframes of each scheduling period, and may occupy only some of the N subframes (as shown in fig. 6), or all of the available resource blocks in the N subframes. N may be a fixed value or may be transmitted in system information. In one design, the resource blocks for the MSCH may be conveyed by control information sent on the PDCCH associated with the PDSCH, as shown in fig. 6.

In general, any number of MTCHs may be used to carry data for an E-MBMS service and any number of MCCHs may be used to carry configuration information for the E-MBMS service. Data for each E-MBMS service may be transmitted on one MTCH, and configuration information for each E-MBMS service may be transmitted on one MCCH. In one design, the MTCH and MCCH of the E-MBMS service may be transmitted starting in subframe N +1 of the scheduling period after the MSCH has been transmitted, as shown in fig. 6. The MTCH and MCCH may be mapped to the DL-SCH and may be transmitted in various resource blocks, which may be distributed throughout the scheduling period. The resource blocks for MTCH and MCCH may be transmitted in several ways. In the design shown in fig. 6, the resource blocks of MTCH and MCCH may be transmitted through scheduling information sent on the MSCH. In this design, the scheduling information includes control information, and the MSCH may effectively be used as an aggregate PDCCH carrying the entire resource blocks of the MBMS service in the scheduling period. Resource blocks for E-MBMS services use PDCCH-less (PDCCH-less) transmission, which means that no control information for these resource blocks is sent on the PDCCH.

In the example shown in fig. 6, PDCCH transmission 610 may provide control information (e.g., resource block allocation and/or other parameters) for MSCH transmission 612. The MSCH transmission 612 may provide scheduling information (e.g., control information such as resource block allocation and/or other parameters) for MCCH transmissions 614 and MTCH transmissions 616 and 618 for E-MBMS service 1. PDCCH transmission 620 may provide control information for MSCH transmission 622. MSCH transmission 622 may provide scheduling information for MTCH transmission 624 for E-MBMS service 2 and MTCH transmissions 626 and 628 for E-MBMS service 3. MSCH transmission may be for a single MSCH or different MSCHs. Likewise, PDCCH transmissions may be for a single PDCCH or different PDCCHs.

Fig. 7 shows another design for transmitting MSCH in single cell mode. In this design, the MSCH may be sent in the first N subframes of each scheduling period, and the resource blocks for the MSCH may be transmitted by the PDCCH. The scheduling information sent on the MSCH may indicate in which sub-frame the MCCH and E-MBMS services are transmitted. The PDCCH may be sent in each subframe indicated by the MSCH and may convey control information (e.g., resource block allocation and/or other parameters) for MCCH and/or MTCH transmissions sent in that subframe. In this design, the MSCH may effectively serve as a pointer to PDCCH transmissions that indicate the resource blocks used for the E-MBMS service in the scheduling period.

In the example shown in fig. 7, PDCCH transmission 710 may provide control information (e.g., resource block allocation and/or other parameters) for MSCH transmission 712. MSCH transmission 712 may provide scheduling information for PDCCH transmission for MCCH and E-MBMS service 1. These PDCCH transmissions may provide control information (e.g., resource block allocation and/or other parameters) for MCCH transmission 714 and MTCH transmissions 716 and 718 for E-MBMS service 1. PDCCH transmission 720 may provide control information for MSCH transmission 722. MSCH transmission 722 may provide scheduling information for PDCCH transmissions for E-MBMS services 2 and 3. These PDCCH transmissions may provide control information for MTCH transmission 724 for E-MBMS service 2 and MTCH transmissions 726 and 728 for E-MBMS service 3.

Fig. 6 and 7 show exemplary transmissions of MSCH, MCCH, and MTCH. In general, any number of MSCH transmissions may be sent in each scheduling period. Any number of MTCH and MCCH transmissions may also be transmitted in each scheduling period and any number of MTCH transmissions may be transmitted for each E-MBMS service. Each transmission may occupy a time-frequency block of arbitrary size.

The UE may know the number of subframes (N), the modulation and coding scheme, and other parameters of the MSCH, or may obtain this information from the D-BCH. Subsequently, the UE may receive the PDCCHs in the N subframes, obtain control information of the MSCH, and receive the MSCH according to the control information. For the design shown in fig. 6, the UE may obtain scheduling information from the MSCH and may receive MCCH and/or MTCH transmissions of interest from this scheduling information. The scheduling information may include control information (e.g., resource block allocation and/or other parameters) for MCCH and/or MTCH transmissions, which are typically sent on the PDCCH. The MCCH may carry configuration information (which may be provided in units of per service) for receiving the E-MBMS service. The configuration information may change infrequently and need not be re-read for each MTCH transmission.

For the design shown in fig. 7, the UE may obtain scheduling information from the MSCH and receive the PDCCH according to the scheduling information. In such a design, the scheduling information may include a resource block pointer, a subframe index, or some other information to find the PDCCH. The UE may then process the PDCCH to obtain control information and may receive MCCH and/or MTCH transmissions according to the control information.

For both designs in fig. 6 and 7, information for receiving MCCH and MTCH transmissions may be reduced by constraining the transmission of MCCH and MTCH. For example, if MCCH and MTCH transmissions are sent in a complete subframe (e.g., as shown in fig. 4), the MSCH may carry the subframe index for MCCH and MTCH transmissions.

The MSCH may be transmitted at the beginning of each scheduling period, as described above and shown in fig. 5-7. The MSCH may also be transmitted before each scheduling period, e.g., in the last N subframes of the previous scheduling period. In general, the MTCH may be periodically transmitted in each scheduling period and may carry scheduling information for the scheduling period and/or a subsequent scheduling period.

Fig. 8 shows a design of a process 800 for transmitting broadcast, multicast, and unicast services in a cellular communication system. Process 800 may be performed by a node B (as described below), or by another entity. The node B may multiplex data for the broadcast and multicast services with data for the unicast service on wireless resources available for transmission (block 812). For example, a node B may also send configuration information for receiving broadcast and multicast services on one or more MCCHs. The configuration information may be referred to as another broadcast service. The node B may periodically send scheduling information for determining radio resources carrying broadcast and multicast services (block 814). The scheduling information may convey where to send the broadcast and multicast services, e.g., time units or time-frequency blocks for these services. The scheduling information also conveys the transmission mode of the broadcast and multicast service, e.g., control information such as modulation and coding used for the broadcast and multicast service.

In one design of block 812, the node B may time division multiplex data for broadcast and multicast services and data for unicast services, e.g., as shown in fig. 5. Each broadcast or multicast service may be transmitted in at least one time unit. Unicast services may be transmitted in time units that are not used for broadcast and multicast services. In this design, the scheduling information may convey a time unit for each broadcast or multicast service.

In another design of block 812, the node B may map data for the broadcast and multicast services to time frequency blocks. The node B may map data for the unicast service to remaining radio resources that are not used for the broadcast and multicast services. In one design, the scheduling information may transmit at least one time frequency block for each broadcast or multicast service, e.g., as shown in fig. 6. In another design, the scheduling information may convey a location of the control information, and the control information may convey at least one time frequency block for each broadcast or multicast service, e.g., as shown in fig. 7. For example, the scheduling information may transmit time units for transmitting broadcast and multicast services, and the control information in each time unit may transmit time-frequency blocks for the broadcast and multicast services transmitted in the time unit.

In one design, the node B may send scheduling information on all available radio resources in the first N time units of each scheduling period, e.g., as shown in FIG. 5. In another design, the node B may transmit the scheduling information on at least one time-frequency block in the first N time units of each scheduling period, e.g., as shown in fig. 6 and 7. In general, the node B may transmit scheduling information in each scheduling period in order to transmit radio resources for broadcast and multicast services in the current and/or subsequent scheduling periods. The node B may also periodically send a flag indicating whether the scheduling information will change in the next scheduling period.

In this design, each broadcast or multicast service may be transmitted by multiple cells in at least one time unit, and the cells may be synchronized, e.g., as shown in fig. 3. In another design, the broadcast and multicast services may be transmitted by a cell and may not be synchronized with broadcast and multicast services transmitted by neighbor cells, e.g., as shown in fig. 4.

Fig. 9 shows a design of an apparatus 900 for transmitting data in a cellular communication system. Apparatus 900 includes a module 912 for multiplexing data of broadcast and multicast services and data of unicast services on wireless resources available for transmission, and a module 914 for periodically transmitting scheduling information for determining wireless resources carrying the broadcast and multicast services.

Fig. 10 shows a design of a process 1000 for receiving service in a cellular communication system. Process 1000 may be performed by a UE (as described below) or by some other entity. The UE may receive scheduling information for broadcast and multicast services multiplexed with unicast services (block 1012). The UE may determine radio resources for at least one of the broadcast and multicast services based on the scheduling information (block 1014). The UE may then process the transmission received on the radio resource to recover data for the at least one service (block 1016).

The UE may receive scheduling information in a scheduling period and may determine radio resources for at least one service in the scheduling period according to the scheduling information. In one design, each service may be transmitted on all available radio resources in at least one time unit, and the UE may determine the time unit to transmit each service based on the scheduling information, e.g., as shown in fig. 5. In another design, each service may be transmitted in at least one time frequency block, and the UE may determine the time frequency block for each service based on the scheduling information, e.g., as shown in fig. 6. In another design, each service may be sent in at least one time frequency block in at least one time unit. The UE may determine (i) a time unit for transmitting each service according to the scheduling information and (ii) a time frequency block for each service according to the control information transmitted in the time unit, for example, as shown in fig. 7.

Fig. 11 shows a design of an apparatus 1100 for receiving data in a cellular communication system. The apparatus 1100 comprises: a module 1112 for receiving scheduling information for broadcast and multicast services multiplexed with unicast services, a module 1114 for determining radio resources for at least one of the broadcast and multicast services based on the scheduling information, and a module 1116 for processing transmissions received on the radio resources to recover data for the at least one service.

The modules in fig. 9 and 11 may include: processors, electronics devices, hardware devices, electronics components, logic circuits, memory, etc., or any combination thereof.

The UE may receive the MSCH in each scheduling period and obtain scheduling information for receiving the MBMS service. The configuration of the E-MBMS service may not change frequently. Each E-MBMS service may be transmitted at a constant bit rate and the same radio resource may be allocated in each scheduling period. The contents of the MSCH may thus change infrequently. In this case, it may be desirable for the UE to reduce its actions by receiving the MSCH only when necessary, and receiving the concerned E-MBMS service from the same resource, in each scheduling period.

In another aspect, a mechanism may be used to prompt the UE in the event that scheduling information on the MSCH changes. In one design, the system information may include an MSCH change indicator flag, which may be referred to as a change flag for short. This change flag is set to (i) a first value (e.g., 0) to indicate that the MSCH is not changed in the next scheduling period, or (ii) a second value (e.g., 1) to indicate that the MSCH is to be changed in the next scheduling period. The change flag may be transmitted at least once per scheduling period. The UE can read the change flag and determine whether to receive the MSCH according to the value of the change flag.

Fig. 12 shows a design of sending an MSCH change indicator flag. In this design, the MSCH is transmitted at the beginning of each scheduling period, and the D-BCH is also transmitted in each scheduling period. The D-BCH may carry the change flag as part of the system information. In the example shown in fig. 12, the contents of the MSCH do not change in scheduling periods 1, 2, and 3, and the change flag in each of these scheduling periods may be set to 0. The contents of MSCH change in scheduling period 4 and the change flag for scheduling period 4 (which may be sent earlier in scheduling period 3) is set to 1.

The UE may receive the MSCH in scheduling period 1 and obtain scheduling information from the MSCH. Since the change flag is set to 0, the UE can receive the E-MBMS service in scheduling period 1 and scheduling periods 2 and 3 using the scheduling information. The UE may detect that the change flag is set to 1 for scheduling period 4 and then receive the MSCH in this scheduling period. The UE may use the scheduling information obtained from the MSCH in scheduling period 4 for each subsequent scheduling period with the change flag set to 0.

In another aspect, a value tag (value) may be used to detect a change in the partial system information carrying the MSCH change indicator flag. The system information may be divided into L shares, each of which may be sent in a respective message, where typically L may be one or greater. Each portion may be associated with a value tag, which may indicate the version of information sent in that portion. The value tag for each portion may be incremented each time the portion changes and may be used by the UE to determine whether they need to read the portion. For example, if the UE last read release 3 of a particular message and observed that the system is sending release 4, the UE may read the message and obtain the update information sent in the message.

The UE may periodically read the system information in order to have the current information. The MSCH change indicator flag may be sent in a portion of the system information, which may be referred to as a flag-carrying portion. Whenever the UE receives the flag-carrying portion, the UE may store the value tag of that portion. The UE may periodically receive a value tag for the flag-carrying portion. If the received value tag matches the stored value tag, the UE may interpret that the tag-carrying portion and the change tag have not changed since the UE last read the portion. In this case, the UE does not need to read the flag carrying part, and does not need to read the change flag. If, for example, during scheduling period 3, the value tag has changed, the UE may read the flag carrying part and obtain the change flag. Then, if the change flag is set to 1, the UE can read the MSCH; and if the change flag is set to 0, the reading of the MSCH is skipped.

Fig. 13 shows a design of a process 1300 for transmitting scheduling information in a cellular communication system. Process 1300 may be performed by a node B (as described below), or by other entities. The node B may periodically send scheduling information for the broadcast and multicast services in each scheduling period (block 1312). The node B may periodically send a flag indicating whether the scheduling information will change in the next scheduling period (block 1314). The node B may periodically send the flag in the portion of the system information associated with the value tag and may update the value tag whenever this portion changes.

Fig. 14 shows a design of an apparatus 1400 for transmitting scheduling information in a cellular communication system. The apparatus 1400 comprises: a module 1412 for periodically transmitting scheduling information for broadcast and multicast services in each scheduling period, and a module 1414 for periodically transmitting a flag indicating whether the scheduling information changes in a next scheduling period.

Fig. 15 shows a design of a process 1500 for receiving scheduling information in a cellular communication system. Process 1500 may be performed by a UE (as described below), or by other entities. The UE may receive scheduling information for the broadcast and multicast services in a first scheduling period (block 1512). The UE may receive a flag indicating whether the scheduling information may change in the second scheduling period (block 1514). If the flag indicates that the scheduling information is to be changed, the UE may receive the scheduling information in a second scheduling period (block 1516). If the flag indicates that the scheduling information does not change, the UE may skip receiving the scheduling information in the second scheduling period (block 1518).

The UE may receive a portion of the system information including a flag and a value tag. The UE receives the flag only if the value tag indicates that the portion of the system information has changed. The UE may receive the scheduling information in the second scheduling period only if the flag is received and indicates that the scheduling information may change.

Fig. 16 shows a design of an apparatus 1600 for receiving scheduling information in a cellular communication system. The apparatus 1600 includes: a module 1612 for receiving scheduling information for broadcast and multicast services in a first scheduling period, a module 1614 for receiving a flag indicating whether the scheduling information will change in a second scheduling period, a module 1616 for receiving scheduling information in the second scheduling period if the flag indicates that the scheduling information will change, a module 1618 for skipping reception of scheduling information in the second scheduling period if the flag indicates that the scheduling information will not change.

The modules in fig. 14 and 16 may include: processors, electronics devices, hardware devices, electronics components, logic circuits, memory, etc., or any combination thereof.

Fig. 17 shows a block diagram of a design of node B110 and UE120, where node B110 and UE120 may be one of the node bs and one of the UEs in fig. 1. In this design, node B110 is equipped with T antennas 1734a through 1734T and UE120 is equipped with R antennas 1752a through 1752R, where, typically, T ≧ 1 and R ≧ 1.

At node B110, a transmit processor 1720 may receive data for a unicast service and data for a broadcast and/or multicast service from a data source 1712. Transmit processor 1720 may process data for each service to obtain data symbols. Transmit processor 1720 may also receive from controller/processor 1740 and/or scheduler 1744: scheduling information, configuration information, control information, system information, and/or other overhead information. Transmit processor 1720 may process the received overhead information and provide overhead symbols. A Transmit (TX) multiple-input multiple-output (MIMO) processor 1730 may multiplex the data and overhead symbols with pilot symbols, process (e.g., precode) the multiplexed symbols, and provide T output symbol streams to T Modulators (MODs) 1732a through 1732T. Each modulator 1732 may process (e.g., for OFDM) a respective output symbol stream to obtain an output sample stream. Each modulator 1732 may also process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 1732a through 1732T may be transmitted via antennas 1734a through 1734T, respectively.

At UE120, antennas 1752a through 1725r may receive the downlink signals from node B110 and provide the received signals to demodulators (DEMODs) 1754a through 1754r, respectively. Each demodulator 1754 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain received samples and further process (e.g., OFDM) the received samples to obtain received symbols. A MIMO detector 1760 may receive and process the received symbols from all R demodulators 1754a through 1754R and provide detected symbols. A receive processor 1770 may process the detected symbols, provide decoded data and/or desired services for UE120 to a data sink 1772, and provide decoded overhead information to a controller/processor 1790. In general, the processing by the MIMO detector 1760 and receive processor 1770 is complementary to the processing by the TXMIMO processor 1730 and transmit processor 1720 at the node B110.

On the uplink, at UE120, data from a data source 1778 and overhead information from controller/processor 1790 may be processed by a transmit processor 1780, further processed by a TXMIMO processor 1782 (if applicable), conditioned by modulators 1754a through 1754r, and transmitted via antennas 1725a through 1752 r. At node B110, the uplink signals from UE120 may be received by antennas 1734, conditioned by demodulators 1732, detected by a MIMO detector 1736, and processed by a receive processor 1738 to obtain the data and overhead information sent by UE 120.

Controllers/processors 1740 and 1790 may direct the operation at node B110 and UE120, respectively. Controller/processor 1749 may implement or direct process 800 in fig. 8, process 1300 in fig. 13, and/or other processes for the techniques described herein. Controller/processor 1790 may implement or direct process 1000 in fig. 10, process 1500 in fig. 15, and/or other processes for the techniques described herein. Memories 1742 and 1792 may store data and program codes for node B110 and UE120, respectively. A scheduler 1744 may schedule UEs for downlink and/or uplink transmissions, schedule transmissions for broadcast and multicast services, and provide assignments of radio resources for the scheduled UEs and services. Controller/processor 1740 and/or scheduler 1744 may generate scheduling information and/or other overhead information for the broadcast and multicast services.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more example designs, the functions described may be implemented as hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be one or more instructions or code stored on or transmitted over on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

The previous description of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (37)

1. A method of transmitting data in a cellular communication system, comprising:

multiplexing data of the broadcast and multicast services with data of the unicast service on radio resources available for downlink transmission; and

periodically transmitting scheduling information for determining radio resources carrying the broadcast and multicast services, wherein the scheduling information conveys information related to at least one time frequency block used by the broadcast or multicast service,

wherein the periodically transmitting transmits the scheduling information for each of a plurality of scheduling periods, each scheduling period comprising a plurality of subframes,

wherein the at least one time frequency block relating to scheduling information for a given scheduling period indicates which of the plurality of sub-frames the broadcast or multicast service uses for the given scheduling period,

wherein a first one of the broadcast and multicast services is assigned a first time frequency block having a first plurality of sub-frames on a first frequency block within the given scheduling period, and

wherein a second one of the broadcast and multicast services or one or more of the unicast services is assigned a second time frequency block having a second plurality of sub-frames on a second frequency block within the given scheduling period.

2. The method of claim 1, wherein the multiplexing comprises:

time division multiplexing data of the broadcast and multicast services with data of the unicast service, each broadcast or multicast service being transmitted in at least one time unit, and wherein the scheduling information further conveys at least one time unit for each broadcast or multicast service.

3. The method of claim 1, wherein the multiplexing comprises:

mapping data of the broadcast and multicast services to time-frequency blocks, and wherein the information on at least one time-frequency block used by the broadcast or multicast service comprises at least one time-frequency block for each broadcast or multicast service.

4. The method of claim 1, wherein the multiplexing comprises:

mapping data of the broadcast and multicast services to time-frequency blocks, and wherein the information related to at least one time-frequency block used by the broadcast or multicast service includes a location of control information conveying the at least one time-frequency block for each broadcast or multicast service.

5. The method of claim 1, wherein the scheduling information further conveys a time unit in which the broadcast and multicast service is transmitted, and wherein control information is transmitted in each time unit in which the broadcast and multicast service is transmitted, and the control information conveys time-frequency blocks for the broadcast and multicast service transmitted in the time unit.

6. The method of claim 1, further comprising:

transmitting configuration information for receiving the broadcast and multicast services, wherein the scheduling information further conveys radio resources carrying the configuration information.

7. The method of claim 1, wherein each broadcast or multicast service is transmitted in at least one time unit by a plurality of cells, the plurality of cells being synchronized.

8. The method of claim 1, wherein the broadcast and multicast service is transmitted by a cell and is not synchronized with broadcast and multicast services transmitted by neighbor cells.

9. The method of claim 1, wherein periodically transmitting the scheduling information comprises:

transmitting the scheduling information in each scheduling period to transmit the radio resources for the broadcast and multicast service in a current or subsequent scheduling period.

10. The method of claim 9, further comprising:

a flag indicating whether the scheduling information will change in a next scheduling period is periodically transmitted.

11. The method of claim 1, wherein periodically transmitting the scheduling information comprises:

transmitting the scheduling information in the first N time units of each scheduling period in order to transmit the radio resources for the broadcast and multicast service in the scheduling period, wherein N is one or more.

12. The method of claim 11, wherein transmitting the scheduling information in the first N time units of each scheduling period comprises:

transmitting the scheduling information on all available radio resources in the first N time units of each scheduling period.

13. The method of claim 11, wherein transmitting the scheduling information in the first N time units of each scheduling period comprises:

transmitting the scheduling information in at least one time frequency block in the first N time units of each scheduling period, an

Transmitting control information conveying at least one time frequency block for the scheduling information.

14. The method of claim 1, wherein the scheduling information further conveys the radio resources carrying the broadcast and multicast services, or parameters for processing transmissions sent on the radio resources, or both.

15. An apparatus configured to transmit scheduling information in a cellular communication system, comprising:

at least one processor configured to:

multiplexing data of the broadcast and multicast services with data of the unicast service on radio resources available for downlink transmission; and

periodically transmitting scheduling information for determining radio resources carrying the broadcast and multicast services, wherein the scheduling information conveys information related to at least one time frequency block used by the broadcast or multicast service,

wherein the at least one processor is configured to transmit the scheduling information for each of a plurality of scheduling periods, each scheduling period comprising a plurality of subframes,

wherein the at least one time frequency block relating to scheduling information for a given scheduling period indicates which of the plurality of sub-frames the broadcast or multicast service uses for the given scheduling period,

wherein a first one of the broadcast and multicast services is assigned a first time frequency block having a first plurality of sub-frames on a first frequency block within the given scheduling period, and

wherein a second one of the broadcast and multicast services or one or more of the unicast services is assigned a second time frequency block having a second plurality of sub-frames on a second frequency block within the given scheduling period.

16. The apparatus of claim 15, wherein the at least one processor is configured to:

time division multiplexing data of said broadcast and multicast services with data of said unicast service, each broadcast or multicast service being transmitted in at least one time unit, and

transmitting the scheduling information to transmit at least one time unit for each broadcast or multicast service.

17. The apparatus of claim 15, wherein the at least one processor is configured to:

mapping data of the broadcast and multicast service to time-frequency blocks, an

Transmitting information on at least one time frequency block used by the broadcast or multicast service to transmit the at least one time frequency block for each broadcast or multicast service.

18. The apparatus of claim 15, wherein the at least one processor is configured to:

mapping data of the broadcast and multicast services to time-frequency blocks,

sending control information conveying at least one time-frequency block for each broadcast or multicast service, an

Transmitting information regarding at least one time frequency block used by the broadcast or multicast service to convey a location of the control information.

19. The apparatus of claim 15, wherein the at least one processor is configured to:

transmitting the scheduling information in each scheduling period to transmit radio resources for the broadcast and multicast service in a current or subsequent scheduling period.

20. An apparatus for use in a cellular communication system, comprising:

means for multiplexing data of broadcast and multicast services with data of unicast services on radio resources available for downlink transmission; and

means for periodically transmitting scheduling information for determining radio resources carrying the broadcast and multicast services, wherein the scheduling information conveys information related to at least one time frequency block used by the broadcast or multicast service,

wherein the means for periodically transmitting transmits the scheduling information for each of a plurality of scheduling periods, each scheduling period comprising a plurality of subframes,

wherein the at least one time frequency block relating to scheduling information for a given scheduling period indicates which of the plurality of sub-frames the broadcast or multicast service uses for the given scheduling period,

wherein a first one of the broadcast and multicast services is assigned a first time frequency block having a first plurality of sub-frames on a first frequency block within the given scheduling period, and

wherein a second one of the broadcast and multicast services or one or more of the unicast services is assigned a second time frequency block having a second plurality of sub-frames on a second frequency block within the given scheduling period.

21. The apparatus of claim 20, wherein the means for multiplexing comprises:

means for time division multiplexing data of the broadcast and multicast services with data of the unicast service, each broadcast or multicast service being transmitted in at least one time unit, and wherein the scheduling information conveys the at least one time unit for each broadcast or multicast service.

22. The apparatus of claim 20, wherein the means for multiplexing comprises:

means for mapping data of the broadcast and multicast services to time-frequency blocks, and wherein the information related to at least one time-frequency block used by the broadcast or multicast service conveys at least one time-frequency block for each broadcast or multicast service.

23. The apparatus of claim 20, wherein the means for multiplexing comprises:

a module that maps data of the broadcast and multicast services to time-frequency blocks, and wherein the information related to at least one time-frequency block used by the broadcast or multicast service conveys the location of control information conveying the at least one time-frequency block for each broadcast or multicast service.

24. The apparatus of claim 20, wherein the means for periodically transmitting the scheduling information comprises:

means for transmitting the scheduling information in each scheduling period to transmit radio resources for the broadcast and multicast service in a current or subsequent scheduling period.

25. A method of receiving data in a cellular communication system, comprising:

receiving scheduling information for broadcast and multicast services multiplexed with a unicast service, wherein the scheduling information conveys information related to at least one time frequency block used by the broadcast or multicast service;

determining radio resources for at least one of the broadcast and multicast services according to the scheduling information; and

processing transmissions received on the radio resource to recover data for the at least one service,

wherein the scheduling information relates to a given scheduling period of a plurality of scheduling periods, each scheduling period comprising a plurality of subframes,

wherein the at least one time frequency block related to scheduling information for the given scheduling period indicates which of the plurality of subframes the broadcast or multicast service uses for the given scheduling period,

wherein a first one of the broadcast and multicast services is assigned a first time frequency block having a first plurality of sub-frames on a first frequency block within the given scheduling period, and

wherein a second one of the broadcast and multicast services or one or more of the unicast services is assigned a second time frequency block having a second plurality of sub-frames on a second frequency block within the given scheduling period.

26. The method of claim 25, wherein:

the receiving of the scheduling information comprises: receiving the scheduling information in the first N time units of a scheduling period, where N is one or more, an

Determining radio resources for the at least one service comprises: determining the radio resources for the at least one service in the scheduling period according to the scheduling information.

27. The method of claim 25, wherein:

each of the at least one service transmits on all available radio resources in at least one time unit, an

Determining the radio resources for the at least one service comprises: determining the at least one time unit in which each service is transmitted according to the scheduling information.

28. The method of claim 25, wherein:

each of the at least one service is transmitted in at least one time-frequency block, an

Determining the radio resources for the at least one service comprises: determining the at least one time frequency block for each service according to the scheduling information.

29. The method of claim 25, wherein:

each of the at least one service is transmitted on at least one time-frequency block in at least one time unit, an

Determining the radio resources for the at least one service comprises:

determining the at least one time unit in which each service is transmitted according to the scheduling information, an

Determining the at least one time frequency block for each service according to control information transmitted in the at least one time unit in which the service is transmitted.

30. An apparatus for wireless communication, comprising:

at least one processor configured to:

receiving scheduling information for broadcast and multicast services multiplexed with unicast services, wherein the scheduling information conveys at least one time frequency block used by the broadcast or multicast services;

determining radio resources for at least one of the broadcast and multicast services according to the scheduling information; and

processing transmissions received on the radio resource to recover data for the at least one service,

wherein the scheduling information relates to a given scheduling period of a plurality of scheduling periods, each scheduling period comprising a plurality of subframes,

wherein the at least one time frequency block related to scheduling information for the given scheduling period indicates which of the plurality of subframes the broadcast or multicast service uses for the given scheduling period,

wherein a first one of the broadcast and multicast services is assigned a first time frequency block having a first plurality of sub-frames on a first frequency block within the given scheduling period, and

wherein a second one of the broadcast and multicast services or one or more of the unicast services is assigned a second time frequency block having a second plurality of sub-frames on a second frequency block within the given scheduling period.

31. The apparatus of claim 30, wherein:

each of the at least one service transmits on all available radio resources in at least one time unit, an

The at least one processor is configured to: determining the at least one time unit in which each service is transmitted according to the scheduling information.

32. The apparatus of claim 30, wherein:

each of the at least one service is transmitted in at least one time-frequency block, an

The at least one processor is configured to: determining the at least one time frequency block for each service according to the scheduling information.

33. The apparatus of claim 30, wherein:

each of the at least one service is transmitted on at least one time-frequency block in at least one time unit, an

The at least one processor is configured to:

determining the at least one time unit in which each service is transmitted according to the scheduling information, an

Determining the at least one time frequency block for each service according to control information transmitted in the at least one time unit in which the service is transmitted.

34. A method of transmitting scheduling information in a cellular communication system, comprising:

periodically transmitting scheduling information for a broadcast and multicast service on a downlink in each scheduling period, wherein the scheduling information conveys at least one time-frequency block used by the broadcast or multicast service; and

periodically transmitting a flag on the downlink indicating whether the scheduling information changes in a next scheduling period.

35. The method of claim 34, further comprising:

periodically transmitting the flag on the downlink in a portion of system information associated with a value tag; and

updating the value tag once the portion of the system information changes.

36. A method of receiving scheduling information in a cellular communication system, comprising:

receiving the scheduling information for a broadcast and multicast service in a first scheduling period on a downlink, wherein the scheduling information comprises information related to at least one time frequency block used by the broadcast or multicast service;

receiving a flag on the downlink indicating whether the scheduling information will change in a second scheduling period;

receiving the scheduling information in the second scheduling period on the downlink if the flag indicates that the scheduling information will change; and

skipping reception of the scheduling information on the downlink in the second scheduling period if the flag indicates that the scheduling information does not change.

37. The method of claim 36, further comprising:

receiving a portion of system information including the flag and value tag, an

Wherein the flag is received only when the value tag indicates that the portion of the system information including the flag has changed, and wherein the scheduling information in the second scheduling period is received only when the flag is received and indicates that the scheduling information is to be changed.