WO2015101085A1

WO2015101085A1 - Improving ue battery power consumption in group communication system enablers

Info

Publication number: WO2015101085A1
Application number: PCT/CN2014/089151
Authority: WO
Inventors: Jun Wang; Xiaoxia Zhang; Xipeng Zhu
Original assignee: Qualcomm Incorporated
Priority date: 2014-01-03
Filing date: 2014-10-22
Publication date: 2015-07-09
Also published as: WO2015100724A1

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may be a UE. In a first configuration, a UE monitors MSI based on a first MSP. The UE receives an MBMS service. The MBMS service is a group communication associated with low latency. Information associated with the MBMS service is included in the MSI. The UE monitors the MSI based on a second MSP less than the first MSP upon receiving the MBMS service. In a second configuration, a UE refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The UE receives an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. The UE monitors the MSI for the particular PMCH upon receiving the group communication via the unicast bearer.

Description

IMPROVING UE BATTERY POWER CONSUMPTION IN GROUP COMMUNICATION SYSTEM ENABLERS

CROSS-REFERENCE TO RELATED APPLICATION (S)

This application claims the benefit of PCT Application No. PCT/CN2014/070068, entitled “IMPROVING UE BATTERY POWER CONSUMPTION IN GROUP COMMUNICATION SYSTEM ENABLERS” and filed on January 3, 2014, which is expressly incorporated by reference herein in its entirety.

BACKGROUND Field

The present disclosure relates generally to communication systems, and more particularly, to improving user equipment (UE) power consumption in group communication system enablers, and in particular, to improving UE power consumption for a multimedia broadcast multicast service (MBMS) bearer in group communication system enablers.

Background

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e. g. , bandwidth, transmit power) . Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunication standard is Long Term Evolution (LTE) . LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP) . LTE is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA on the downlink (DL) , SC-FDMA on the uplink (UL) , and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

In a first aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a UE. The UE monitors multicast channel (MCH) scheduling information (MSI) based on a first MCH scheduling period (MSP) . The UE receives a multicast broadcast multimedia service (MBMS) service. The MBMS service is a group communication associated with low latency. The information associated with the MBMS service is included in the MSI. The UE monitors the MSI based on a second MSP less than the first MSP upon receiving the MBMS service. The UE may receive an indication that the MSI should be monitored based on the second MSP rather than the first MSP upon receiving the group communication. The UE may receive system information indicating a multicast control channel (MCCH) modification period in which an MSP can be changed. The MCCH modification period may be less than or equal to 5.12 seconds.

In a second aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a UE. The UE refrains from monitoring MSI for a physical multicast channel (PMCH) when not receiving an MBMS service on the PMCH. The UE receives an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. The UE monitors the MSI for the particular PMCH upon receiving the group communication via the unicast bearer. The UE may receive a remaining part of the group communication via an MBMS bearer. The UE may receive a configuration for the MBMS bearer before refraining from monitoring the MSI.

In a third aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a UE. The UE receives an initial part of a group communication associated with low latency via a unicast bearer. The UE determines whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer. The UE determines to monitor MSI for a PMCH of the group communication after not having monitored MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer. The UE may receive an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer. The UE may determine whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication. The UE may receive a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer. The UE may receive the remaining part of the group communication via the MBMS bearer. The UE may receive system information indicating an MCCH modification period in which a MSP for receiving the MSI can be changed. The MCCH modification period may be less than or equal to 5.12 seconds.

In a fourth aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a UE. The UE receives an MSI change notification, and obtains the MSI based on the received MSI change notification. The UE may also determine whether a group communication associated with low latency is scheduled based on the obtained MSI, and monitor the MSI periodically upon determining the group communication is scheduled. The UE may determine a group communication associated with low latency is scheduled based on the obtained MSI, and monitor the MSI periodically upon determining the group communication is scheduled. The MSI change notification may include information associated with a temporary mobile group identity (TMGI) , and the UE may obtain the MSI for a PMCH associated with the TMGI. The UE may determine the TMGI is for a group communication associated with low latency, and monitor the MSI for the PMCH periodically upon determining the TMGI is for the group communication. The MSI change notification may indicate which Multicast Broadcast Single Frequency Networks (MBSFNs) have an MSI change, and the UE may obtain the MSI for each PMCH of the MBSFNs indicated in the MSI change notification. The MSI change notification may indicate which PMCHs have an MSI change, and the UE may obtain the MSI for each of the indicated PMCHs. The MSI change notification may be received together with an MCCH change notification in a same physical downlink control channel (PDCCH) . The MSI change notification and an MCCH change notification may be received separately in different PDCCHs.

In a fifth aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a UE. The UE refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The UE receives a paging message indicating a group communication associated with low latency. The group communication is associated with a particular PMCH. The UE monitors the MSI for the particular PMCH upon receiving the paging message. The paging message may be one of a unicast paging message or a group paging message. The paging message may include information associated with a TMGI. The TMGI may be associated with the particular PMCH. The UE may obtain the MSI for the particular PMCH associated with the TMGI. The UE may receive the group communication via an MBMS bearer. The UE may receive a configuration for the MBMS bearer before refraining from monitoring the MSI.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a network architecture.

FIG. 2 is a diagram illustrating an example of an access network.

FIG. 3 is a diagram illustrating an example of a DL frame structure in LTE.

FIG. 4 is a diagram illustrating an example of an UL frame structure in LTE.

FIG. 5 is a diagram illustrating an example of a radio protocol architecture for the user and control planes.

FIG. 6 is a diagram illustrating an example of an evolved Node B and user equipment in an access network.

FIG. 7A is a diagram illustrating an example of an evolved Multimedia Broadcast Multicast Service channel configuration in a Multicast Broadcast Single Frequency Network.

FIG. 7B is a diagram illustrating a format of a Multicast Channel Scheduling Information Media Access Control control element.

FIG. 8 is a diagram for illustrating a first exemplary method.

FIG. 9 is a diagram for illustrating a second exemplary method.

FIG. 10 is a diagram for illustrating a third exemplary method.

FIG. 11 is a diagram for illustrating a fourth exemplary method.

FIG. 12 is a diagram for illustrating a fifth exemplary method.

FIG. 13 is a flow chart of a first method of wireless communication.

FIG. 14 is a flow chart of a second method of wireless communication.

FIG. 15 is a flow chart of a third method of wireless communication.

FIG. 16 is a flow chart of a fourth method of wireless communication.

FIG. 17 is a flow chart of a fifth method of wireless communication.

FIG. 18 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus.

FIG. 19 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented with a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc. , whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , compact disk ROM (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 computer. Combinations of the above should also be included within the scope of computer-readable media.

FIG. 1 is a diagram illustrating an LTE network architecture 100. The LTE network architecture 100 may be referred to as an Evolved Packet System (EPS) 100. The EPS 100 may include one or more user equipment (UE) 102, an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) 104, an Evolved Packet Core (EPC) 110, and an Operator’s Internet Protocol (IP) Services 122. The EPS can interconnect with other access networks, but for simplicity those entities/interfaces are not shown. As shown, the EPS provides packet-switched services, however, as those skilled in the art will readily appreciate, the various concepts presented throughout this disclosure may be extended to networks providing circuit-switched services.

The E-UTRAN includes the evolved Node B (eNB) 106 and other eNBs 108, and may include a Multicast Coordination Entity (MCE) 128. The eNB 106 provides user and control planes protocol terminations toward the UE 102. The eNB 106 may be connected to the other eNBs 108 via a backhaul (e. g., an X2 interface) . The MCE 128 allocates time/frequency radio resources for evolved Multimedia Broadcast Multicast Service (MBMS) (eMBMS) , and determines the radio configuration (e. g. , a modulation and coding scheme (MCS) ) for the eMBMS. The MCE 128 may be a separate entity or part of the eNB 106. The eNB 106 may also be referred to as a base station, a Node B, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , or some other suitable terminology. The eNB 106 provides an access point to the EPC 110 for a UE 102. Examples of UEs 102 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e. g. , MP3 player) , a camera, a game console, a tablet, or any other similar functioning device. The UE 102 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

The eNB 106 is connected to the EPC 110. The EPC 110 may include a Mobility Management Entity (MME) 112, a Home Subscriber Server (HSS) 120, other MMEs 114, a Serving Gateway 116, a Multimedia Broadcast Multicast Service (MBMS) Gateway (GW) (MBMS-GW) 124, a Broadcast Multicast Service Center (BM-SC) 126, and a Packet Data Network (PDN) Gateway 118. The MME 112 is the control node that processes the signaling between the UE 102 and the EPC 110. Generally, the MME 112 provides bearer and connection management. All user IP packets are transferred through the Serving Gateway 116, which itself is connected to the PDN Gateway 118. The PDN Gateway 118 provides UE IP address allocation as well as other functions. The PDN Gateway 118 and the BM-SC 126 are connected to the IP Services 122. The IP Services 122 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service (PSS) , and/or other IP services. The BM-SC 126 may provide functions for MBMS user service provisioning and delivery. The BM-SC 126 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a PLMN, and may be used to schedule and deliver MBMS transmissions. The MBMS Gateway 124 may be used to distribute MBMS traffic to the eNBs (e. g. , 106, 108) belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

FIG. 2 is a diagram illustrating an example of an access network 200 in an LTE network architecture. In this example, the access network 200 is divided into a number of cellular regions (cells) 202. One or more lower power class eNBs 208 may have cellular regions 210 that overlap with one or more of the cells 202. The lower power class eNB 208 may be a femto cell (e. g. , home eNB (HeNB) ) , pico cell, micro cell, a small cell or remote radio head (RRH) . The macro eNBs 204 are each assigned to a respective cell 202 and are configured to provide an access point to the EPC 110 for all the UEs 206 in the cells 202. There is no centralized controller in this example of an access network 200, but a centralized controller may be used in alternative configurations. The eNBs 204 are responsible for all radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and connectivity to the serving gateway 116. An eNB may support one or multiple (e. g. , three) cells (also referred to as a sectors) . The term “cell” can refer to the smallest coverage area of an eNB and/or an eNB subsystem serving are particular coverage area. Further, the terms “eNB, ” “base station, ” and “cell” may be used interchangeably herein.

The modulation and multiple access scheme employed by the access network 200 may vary depending on the particular telecommunications standard being deployed. In LTE applications, OFDM is used on the DL and SC-FDMA is used on the UL to support both frequency division duplex (FDD) and time division duplex (TDD) . As those skilled in the art will readily appreciate from the detailed description to follow, the various concepts presented herein are well suited for LTE applications. However, these concepts may be readily extended to other telecommunication standards employing other modulation and multiple access techniques. By way of example, these concepts may be extended to Evolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB) . EV-DO and UMB are air interface standards promulgated by the 3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and employs CDMA to provide broadband Internet access to mobile stations. These concepts may also be extended to Universal Terrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) and other variants of CDMA, such as TD-SCDMA； Global System for Mobile Communications (GSM) employing TDMA； and Evolved UTRA (E-UTRA) , IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from the 3GPP organization. CDMA2000 and UMB are described in documents from the 3GPP2 organization. The actual wireless communication standard and the multiple access technology employed will depend on the specific application and the overall design constraints imposed on the system.

The eNBs 204 may have multiple antennas supporting MIMO technology. The use of MIMO technology enables the eNBs 204 to exploit the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different streams of data simultaneously on the same frequency. The data streams may be transmitted to a single UE 206 to increase the data rate or to multiple UEs 206 to increase the overall system capacity. This is achieved by spatially precoding each data stream (i. e. , applying a scaling of an amplitude and a phase) and then transmitting each spatially precoded stream through multiple transmit antennas on the DL. The spatially precoded data streams arrive at the UE (s) 206 with different spatial signatures, which enables each of the UE (s) 206 to recover the one or more data streams destined for that UE 206. On the UL, each UE 206 transmits a spatially precoded data stream, which enables the eNB 204 to identify the source of each spatially precoded data stream.

Spatial multiplexing is generally used when channel conditions are good. When channel conditions are less favorable, beamforming may be used to focus the transmission energy in one or more directions. This may be achieved by spatially precoding the data for transmission through multiple antennas. To achieve good coverage at the edges of the cell, a single stream beamforming transmission may be used in combination with transmit diversity.

In the detailed description that follows, various aspects of an access network will be described with reference to a MIMO system supporting OFDM on the DL. OFDM is a spread-spectrum technique that modulates data over a number of subcarriers within an OFDM symbol. The subcarriers are spaced apart at precise frequencies. The spacing provides “orthogonality” that enables a receiver to recover the data from the subcarriers. In the time domain, a guard interval (e. g. , cyclic prefix) may be added to each OFDM symbol to combat inter-OFDM-symbol interference. The UL may use SC-FDMA in the form of a DFT-spread OFDM signal to compensate for high peak-to-average power ratio (PAPR) .

FIG. 3 is a diagram 300 illustrating an example of a DL frame structure in LTE. A frame (10 ms) may be divided into 10 equally sized subframes. Each subframe may include two consecutive time slots. A resource grid may be used to represent two time slots, each time slot including a resource block. The resource grid is divided into multiple resource elements. In LTE, for a normal cyclic prefix, a resource block contains 12 consecutive subcarriers in the frequency domain and 7 consecutive OFDM symbols in the time domain, for a total of 84 resource elements. For an extended cyclic prefix, a resource block may contain 12 consecutive subcarriers in the frequency domain and 6 consecutive OFDM symbols in the time domain, for a total of 72 resource elements. Some of the resource elements, indicated as

R

302, 304, include DL reference signals (DL-RS) . The DL-RS include Cell-specific RS (CRS) (also sometimes called common RS) 302 and UE-specific RS (UE-RS) 304. UE-RS 304 are transmitted only on the resource blocks upon which the corresponding physical DL shared channel (PDSCH) is mapped. The number of bits carried by each resource element depends on the modulation scheme. Thus, the more resource blocks that a UE receives and the higher the modulation scheme, the higher the data rate for the UE.

FIG. 4 is a diagram 400 illustrating an example of an UL frame structure in LTE. The available resource blocks for the UL may be partitioned into a data section and a control section. The control section may be formed at the two edges of the system bandwidth and may have a configurable size. The resource blocks in the control section may be assigned to UEs for transmission of control information. The data section may include all resource blocks not included in the control section. The UL frame structure results in the data section including contiguous subcarriers, which may allow a single UE to be assigned all of the contiguous subcarriers in the data section.

A UE may be assigned

resource blocks

410a, 410b in the control section to transmit control information to an eNB. The UE may also be assigned

resource blocks

420a, 420b in the data section to transmit data to the eNB. The UE may transmit control information in a physical UL control channel (PUCCH) on the assigned resource blocks in the control section. The UE may transmit only data or both data and control information in a physical UL shared channel (PUSCH) on the assigned resource blocks in the data section. A UL transmission may span both slots of a subframe and may hop across frequency.

A set of resource blocks may be used to perform initial system access and achieve UL synchronization in a physical random access channel (PRACH) 430. The PRACH 430 carries a random sequence and cannot carry any UL data/signaling. Each random access preamble occupies a bandwidth corresponding to six consecutive resource blocks. The starting frequency is specified by the network. That is, the transmission of the random access preamble is restricted to certain time and frequency resources. There is no frequency hopping for the PRACH. The PRACH attempt is carried in a single subframe (1 ms) or in a sequence of few contiguous subframes and a UE can make only a single PRACH attempt per frame (10 ms) .

FIG. 5 is a diagram 500 illustrating an example of a radio protocol architecture for the user and control planes in LTE. The radio protocol architecture for the UE and the eNB is shown with three layers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowest layer and implements various physical layer signal processing functions. The L1 layer will be referred to herein as the physical layer 506. Layer 2 (L2 layer) 508 is above the physical layer 506 and is responsible for the link between the UE and eNB over the physical layer 506.

In the user plane, the L2 layer 508 includes a media access control (MAC) sublayer 510, a radio link control (RLC) sublayer 512, and a packet data convergence protocol (PDCP) 514 sublayer, which are terminated at the eNB on the network side. Although not shown, the UE may have several upper layers above the L2 layer 508 including a network layer (e. g. , IP layer) that is terminated at the PDN gateway 118 on the network side, and an application layer that is terminated at the other end of the connection (e. g. , far end UE, server, etc. ) .

The PDCP sublayer 514 provides multiplexing between different radio bearers and logical channels. The PDCP sublayer 514 also provides header compression for upper layer data packets to reduce radio transmission overhead, security by ciphering the data packets, and handover support for UEs between eNBs. The RLC sublayer 512 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to hybrid automatic repeat request (HARQ) . The MAC sublayer 510 provides multiplexing between logical and transport channels. The MAC sublayer 510 is also responsible for allocating the various radio resources (e. g. , resource blocks) in one cell among the UEs. The MAC sublayer 510 is also responsible for HARQ operations.

In the control plane, the radio protocol architecture for the UE and eNB is substantially the same for the physical layer 506 and the L2 layer 508 with the exception that there is no header compression function for the control plane. The control plane also includes a radio resource control (RRC) sublayer 516 in Layer 3 (L3 layer) . The RRC sublayer 516 is responsible for obtaining radio resources (e. g. , radio bearers) and for configuring the lower layers using RRC signaling between the eNB and the UE.

FIG. 6 is a block diagram of an eNB 610 in communication with a UE 650 in an access network. In the DL, upper layer packets from the core network are provided to a controller/processor 675. The controller/processor 675 implements the functionality of the L2 layer. In the DL, the controller/processor 675 provides header compression, ciphering, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocations to the UE 650 based on various priority metrics. The controller/processor 675 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the UE 650.

The transmit (TX) processor 616 implements various signal processing functions for the L1 layer (i. e. , physical layer) . The signal processing functions include coding and interleaving to facilitate forward error correction (FEC) at the UE 650 and mapping to signal constellations based on various modulation schemes (e. g. , binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols are then split into parallel streams. Each stream is then mapped to an OFDM subcarrier, multiplexed with a reference signal (e. g. , pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream may be spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 674 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 650. Each spatial stream may then be provided to a different antenna 620 via a separate transmitter 618TX. Each transmitter 618TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 650, each receiver 654RX receives a signal through its respective antenna 652. Each receiver 654RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 656. The RX processor 656 implements various signal processing functions of the L1 layer. The RX processor 656 may perform spatial processing on the information to recover any spatial streams destined for the UE 650. If multiple spatial streams are destined for the UE 650, they may be combined by the RX processor 656 into a single OFDM symbol stream. The RX processor 656 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB 610. These soft decisions may be based on channel estimates computed by the channel estimator 658. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB 610 on the physical channel. The data and control signals are then provided to the controller/processor 659.

The controller/processor 659 implements the L2 layer. The controller/processor can be associated with a memory 660 that stores program codes and data. The memory 660 may be referred to as a computer-readable medium. In the UL, the controller/processor 659 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the core network. The upper layer packets are then provided to a data sink 662, which represents all the protocol layers above the L2 layer. Various control signals may also be provided to the data sink 662 for L3 processing. The controller/processor 659 is also responsible for error detection using an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support HARQ operations.

In the UL, a data source 667 is used to provide upper layer packets to the controller/processor 659. The data source 667 represents all protocol layers above the L2 layer. Similar to the functionality described in connection with the DL transmission by the eNB 610, the controller/processor 659 implements the L2 layer for the user plane and the control plane by providing header compression, ciphering, packet segmentation and reordering, and multiplexing between logical and transport channels based on radio resource allocations by the eNB 610. The controller/processor 659 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the eNB 610.

Channel estimates derived by a channel estimator 658 from a reference signal or feedback transmitted by the eNB 610 may be used by the TX processor 668 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 668 may be provided to different antenna 652 via separate transmitters 654TX. Each transmitter 654TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB 610 in a manner similar to that described in connection with the receiver function at the UE 650. Each receiver 618RX receives a signal through its respective antenna 620. Each receiver 618RX recovers information modulated onto an RF carrier and provides the information to a RX processor 670. The RX processor 670 may implement the L1 layer.

The controller/processor 675 implements the L2 layer. The controller/processor 675 can be associated with a memory 676 that stores program codes and data. The memory 676 may be referred to as a computer-readable medium. In the UL, the control/processor 675 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover upper layer packets from the UE 650. Upper layer packets from the controller/processor 675 may be provided to the core network. The controller/processor 675 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

FIG. 7A is a diagram 750 illustrating an example of an evolved MBMS (eMBMS) channel configuration in an MBSFN. Herein, eMBMS may be referred to generally as MBMS. The eNBs 752 in cells 752'may form a first MBSFN area and the eNBs 754 in cells 754'may form a second MBSFN area. The

eNBs

752, 754 may each be associated with other MBSFN areas, for example, up to a total of eight MBSFN areas. A cell within an MBSFN area may be designated a reserved cell. Reserved cells do not provide multicast/broadcast content, but are time-synchronized to the cells 752', 754'a nd may have restricted power on MBSFN resources in order to limit interference to the MBSFN areas. Each eNB in an MBSFN area synchronously transmits the same eMBMS control information and data. Each area may support broadcast, multicast, and unicast services. A unicast service is a service intended for a specific user, e. g. , a voice call. A multicast service is a service that may be received by a group of users, e. g. , a subscription video service. A broadcast service is a service that may be received by all users, e. g. , a news broadcast. Referring to FIG. 7A, the first MBSFN area may support a first eMBMS broadcast service, such as by providing a particular news broadcast to UE 770. The second MBSFN area may support a second eMBMS broadcast service, such as by providing a different news broadcast to UE 760. Each MBSFN area supports a plurality of physical multicast channels (PMCH) (e. g. , 15 PMCHs) . Each PMCH corresponds to a multicast channel (MCH) . Each MCH can multiplex a plurality (e. g. , 29) of multicast logical channels. Each MBSFN area may have one multicast control channel (MCCH) . As such, one MCH may multiplex one MCCH and a plurality of multicast traffic channels (MTCHs) and the remaining MCHs may multiplex a plurality of MTCHs.

A UE can camp on an LTE cell to discover the availability of eMBMS service access and a corresponding access stratum configuration. In a first step, the UE may acquire a system information block (SIB) 13 (SIB13) . In a second step, based on the SIB13, the UE may acquire an MBSFN area configuration message on an MCCH. In a third step, based on the MBSFN area configuration message, the UE may acquire an MCH scheduling information (MSI) MAC control element. The SIB13 may indicate (1) an MBSFN area identifier of each MBSFN area supported by the cell； (2) information for acquiring the MCCH such as an MCCH repetition period (e. g. , 32, 64, …, 256 frames) , an MCCH offset (e. g. , 0, 1, …, 10 frames) , an MCCH modification period (e. g. , 512, 1024 frames) , a signaling modulation and coding scheme (MCS) , subframe allocation information indicating which subframes of the radio frame as indicated by repetition period and offset can transmit MCCH； and (3) an MCCH change notification configuration. There is one MBSFN area configuration message for each MBSFN area. The MBSFN area configuration message may indicate (1) a temporary mobile group identity (TMGI) and an optional session identifier of each MTCH identified by a logical channel identifier within the PMCH, and (2) allocated resources (i. e. , radio frames and subframes) for transmitting each PMCH of the MBSFN area and the allocation period (e. g. , 4, 8, …, 256 frames) of the allocated resources for all the PMCHs in the area, and (3) an MCH scheduling period (MSP) (e. g. , 8, 16, 32, …, or 1024 radio frames) over which the MSI MAC control element is transmitted.

FIG. 7B is a diagram 790 illustrating the format of an MSI MAC control element. The MSI MAC control element may be sent once each MSP. The MSI MAC control element may be sent in the first subframe of each scheduling period of the PMCH. The MSI MAC control element can indicate the stop frame and subframe of each MTCH within the PMCH. There may be one MSI per PMCH per MBSFN area.

Group communication system enablers (GCSE) (also referred to as group call system enablers) support efficient and dynamic group communication operations such as one-to-many calling and dispatcher calls. Due to the nature of the group communications, using unicast bearers may result in inefficient use of network resources where all target users in the group are listening to the same content via a unicast bearer. Therefore, an MBMS bearer (which has a one-to-one mapping with an MTCH) may provide more efficient use of network resources for a group communication, especially when most UEs in the group are located within the MBSFN area. However, MBMS bearer setup delay may be an issue when providing group communication service via an MBMS bearer. GCSE may be used for public safety communications, and in particular, for services requiring low latency in which the group communication/call is established quickly when the caller initiates the group communication/call. In GCSE, pre-established MBMS bearers may be used to reduce call setup latency. The TMGIs associated with the MBMS bearers for the group communication may be preconfigured. The network may set up MBMS sessions for the group communication in preconfigured MBSFN areas. All members in a group may receive a user service description (USD) and perform MBMS service registrations and key requests in advance of the group communication. The MCCH may contain the corresponding TMGI and MBMS session information. If there is no group communication data, the MBMS resources allocated for the group communication may be used for unicast traffic data. When an eNB receives group communication data from the MBMS-GW (see FIG. 1) , the MSI may be updated to include information indicating the scheduling of the group communication (start/stop times) (see FIG. 7B) . The UE may monitor the MSI periodically in order to determine the MTCH (identified by a logical channel identifier) for the group communication and the start/stop times for the group communication. When the MSP is set to a short time period (80 ms) to achieve a short end-to-end transport delay (for example, 150 ms) , UE battery power consumption may be an issue when providing group communication service via an MBMS bearer because the UE needs to monitor the MSI every 80 ms in order to determine the updated scheduling information for the ongoing group communication. Monitoring the MSI every 80 ms may cause the UE to wake up once every 80ms and to consume too much battery power. Requirements for a group communication may allow the UE to have a longer delay when a group communication starts, for example, a maximum delay of 320 ms, and thereafter may require the UE to have a shorter transport delay for data, for example, a maximum delay of 80 ms. Accordingly, methods and apparatuses are needed for reducing UE power consumption in GCSE to avoid the UE having to monitor MSI very frequently before the group communication starts.

FIG. 8 is a diagram 800 for illustrating a first exemplary method. In the first exemplary method, a UE may initially monitor the MSI with a first MSP, such as 320 ms. After the group communication starts, the UE may monitor the MSI with a second MSP, such as 80 ms. The MSP may be changed once each MCCH modification period. As such, changing the MSP may cause a delay as long as the MCCH modification period. Referring to FIG. 8, a UE 804 monitors 806 MSI based on a first MSP. The UE 804 receives MSI from the eNB 802. The MSI includes information associated with MBMS services. Assume at least one of the MBMS services is a group communication. The group communication may be a low latency MBMS service. The group communication may be associated with public safety notifications/messages. Based on the scheduling information in the MSI, the UE receives the group communication from the eNB 802. Thereafter, the UE 804 monitors 806 the MSI based on a second MSP less than the first MSP. In one example, the second MSP is 80 ms and the first MSP is greater than 80 ms.

Upon receiving the first data burst of the group communication, the UE 804 may receive an indication that the MSI should be monitored based on the second MSP rather than the first MSP. The indication may be an MBSFN area configuration message. The MBSFN area configuration message may be updated in the beginning of each MCCH modification period. In order to reduce the time for changing the MSP, the UE 804 may receive system information (e. g. , SIB13) from the eNB 802 indicating an MCCH modification period in which the MSP can be changed, where the MCCH modification period is less than or equal to 5.12 seconds (512 frames) . In one example, the MCCH modification period is less than or equal to 1.28 seconds (128 frames) .

FIG. 9 is a diagram 900 for illustrating a second exemplary method. In the second exemplary method, a UE receives a unicast page and then enters an RRC connected state. The UE then receives the group communication data via the unicast bearer. When the UE detects that a group communication associated with a pre-established TMGI is being received via the unicast bearer, the UE immediately (or shortly thereafter) switches to the corresponding MBMS bearer to receive the group communication. The MBMS bearer is preconfigured to enable the UE to switch to receiving the group communication via the MBMS bearer shortly after starting to receive the group communication data (for example, group communication control signaling) . Even though the MBMS bearer is set up and is preconfigured, the UE does not monitor the MSI until the first burst of the group communication is received via the unicast bearer. Once the UE detects that a group communication is received via the unicast bearer, the UE switches to receiving the group communication via the preconfigured MBMS bearer. An application server (AS) may send the group communication on both the unicast and MBMS bearers in the beginning of the group communication until the unicast bearer is released.

Referring to FIG. 9, a UE 904 receives a configuration for an MBMS bearer. Although preconfigured for an MBMS bearer, the UE 904 refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The UE 904 receives, from an eNB 902, an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. The UE 904 thereafter monitors 906 the MSI for the particular MTCH on the PMCH. Subsequently, the UE 904 receives a remaining part of the group communication via the preconfigured MBMS bearer.

FIG. 10 is a diagram 1000 for illustrating a third exemplary method. In the third exemplary method, a UE receives a unicast page and then enters an RRC connected state. The UE thereafter receives the group communication data via the unicast bearer. If an AS determines the number of UEs within a group receiving the group communication is less than a threshold, the UE may continue to receive the group communication via the unicast bearer. However, if the AS determines the number of UEs within a the group receiving the group communication is greater than the threshold, the UE may immediately (or shortly thereafter) switch to receiving the group communication via an MBMS bearer. In this exemplary method, the MBMS bearer may not be preconfigured. As such, the network may set up the MBMS bearer upon the AS determining that the number of UEs within the group receiving the group communication is greater than the threshold.

Referring to FIG. 10, a UE 1004 receives an initial part of a group communication associated with low latency via a unicast bearer from the eNB 1102. The UE 1004 determines whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer. If the UE detects the group communication data is also sent via an MBMS bearer, for example by reading the USD and SIB, the UE switches to the MBMS bearer. Another method is that the UE 1004 may receive an indication from the network of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer. The UE 1004 may determine whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication or redirection from the network. Upon determining to receive the remaining part of the group communication via the MBMS bearer, the UE 1004 may receive a configuration through a SIB or MCCH for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer. The UE 1004 may determine to monitor 1006 MSI for a PMCH of the group communication after not having monitored MSI for the PMCH. Thereafter, the UE may receive the remaining part of the group communication via the MBMS bearer. The UE 1004 may receive system information (e. g. , SIB13) indicating an MCCH modification period in which an MSP for receiving the MSI can be changed. The MCCH modification period may be less than or equal to 5.12 seconds in order to reduce the time period for the UE 1004 to receive the configuration including the MSP for the MBMS bearer. In one example, the MCCH modification period is less than or equal to 1.28 seconds.

FIG. 11 is a diagram 1100 for illustrating a fourth exemplary method. In the fourth exemplary method, a UE may receive an MSI change notification indicating that MSI has changed, and then obtain the updated MSI upon receiving the MSI change notification. In such a configuration, the UE assumes the received MSI is valid (and that the scheduling pattern repeats) until an MSI change notification is received. If MSI is obtained indicating that a group communication is scheduled, the UE may begin monitoring the MSI at the MSP. The MSP may be less than or equal to 80 ms. However, before obtaining MSI indicating that a group communication is scheduled, the UE may not monitor the MSI.

The MSI change notification may use reserved bits from a PDCCH that also carries the MCCH change notification. Alternatively, the MSI change notification may be received in a different/new PDCCH. The CRC of the new PDCCH may be scrambled by an MBMS radio network temporary identifier (RNTI) (M-RNTI) or a group RNTI (G-RNTI) . To minimize the bits used in the PDCCH, a single bit per MBSFN area may be used to indicate any MSI change per MBSFN area. A SIB may indicate the utilized bits to MBSFN area mapping in the PDCCH. If a different/new PDCCH is introduced for the MSI change notification, a SIB may further indicate when the PDCCH is sent. The different/new PDCCH does not transmit in the same subframe as the MCCH change notification if also scrambled by an M-RNTI. Accordingly, the UE will need to wake up to monitor both the MCCH and the MSI change notifications. To reduce UE power consumption, the MSI change notification can further carry a group ID identifying a group of UEs or a TMGI associated with the group communication. The group ID identifies the UEs for which the group communication is intended and can be mapped back to a TMGI associated with the group communication. To minimize PDCCH overhead, an index can be introduced in the MSI change notification which maps to the group ID or the TMGI. The index can be indicated in a SIB.

In one example, with 10 MHz, the current PDCCH change notification has 13 bits for payload. Assume two MBSFN areas are configured in the current cell. Then two bits are used for the MCCH change notification. Two more bits may be used for the MSI change notification. The remaining nine bits can be used to signal whether a particular group or TMGI has an MSI change. Up to nine groups or TMGIs can be indicated on each PDCCH.

In a first configuration, an eNB may send an MSI change notification on the PDCCH upon receiving data from the MBMS-GW. With the MSI change notification, UE battery consumption may be improved, as the UE does not need to decode repeatedly the MSI when the scheduling pattern of the MSI does not change. However, the eNB may need to detect data received for a specific TMGI reserved for group call to trigger the MSI change notification message.

In a second configuration, the BM-SC sends an MBMS session modification to the MCE and the MCE sends (through the eNB) the MSI change notification. With the MSI change notification, UE battery consumption may be improved. Also, the eNB does not need to distinguish between a group communication and regular MBMS services.

Referring to FIG. 11, a UE 1104 receives an MSI change notification from the eNB 1102, and obtains the MSI based on the received MSI change notification. The UE 1104 may determine a group communication associated with low latency is scheduled based on the obtained MSI. The UE 1104 may then monitor 1106 the MSI periodically upon determining the group communication is scheduled. The MSI change notification may include information associated with a TMGI. The information associated with a TMGI may be the TMGI itself, or may be a group ID that can be mapped to the TMGI. The UE 1104 obtains the MSI for a PMCH associated with the TMGI. The UE 1104 may determine the TMGI is for a group communication associated with low latency, and monitor 1106 the MSI for the PMCH periodically upon determining the TMGI is for the group communication. The MSI change notification may indicate which MBSFNs have an MSI change. In such a configuration, the UE 1104 obtains the MSI for each PMCH of the MBSFNs indicated in the MSI change notification. The MSI change notification may indicate which PMCHs have an MSI change. In such a configuration, the UE 1104 obtains the MSI for each of the indicated PMCHs. The MSI change notification may be received by the UE 1104 together with an MCCH change notification in the same PDCCH. Alternatively, the MSI change notification and an MCCH change notification are received by the UE 1104 separately in different PDCCHs.

FIG. 12 is a diagram 1200 for illustrating a fifth exemplary method. In the fifth exemplary method, a UE may receive a paging message indicating to the UE to monitor the MSI and receive the group communication data via an MBMS bearer. If the paging message is a unicast paging message (targeted to each international mobile subscriber identity (IMSI) ) , the unicast paging message may include a flag for indicating to the UE whether to monitor the MSI. The paging message may be a group paging message using a unicast paging occasion or using a group paging occasion per group ID or TMGI. The paging message may be scheduled on the PDCCH with a CRC scrambled by a paging RNTI (P-RNTI) or a G-RNTI. The PDSCH may carry the actual RRC paging message with a group ID or TMGI included.

In a first configuration, an eNB may send the group or unicast paging to the UEs. In such a configuration, the eNB may need to detect data received for a specific TMGI reserved for a group communication to trigger the paging message. In a second configuration, the BM-SC may send an MBMS session modification to the MME to trigger the MME to send (through the eNB) the group or unicast paging. In such a configuration, the eNB may not need to distinguish between a group communication and regular MBMS services. In both configurations, UE battery consumption may be improved due to the reduced decoding of the MSI before the group communication starts.

Referring to FIG. 12, an MBMS bearer is preconfigured for a UE 1204. Accordingly, the UE 1204 receives a configuration for the MBMS bearer. Subsequently, the UE 1204 refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The UE 1204 receives from the eNB 1202 a paging message indicating a group communication associated with low latency. The group communication is associated with a particular MTCH on the PMCH. Thereafter, the UE 1204 monitors 1206 the MSI for the particular PMCH upon receiving the paging message. The paging message may be a unicast paging message or a group paging message. The paging message may include information associated with a TMGI. The information associated with a TMGI may be the TMGI itself or a group ID that the UE 1204 can map to the TMGI. The TMGI is associated with the particular MTCH on the PMCH. The UE 1204 obtains the MSI for the particular PMCH associated with the TMGI. The UE 1204 subsequently receives the group communication via the preconfigured MBMS bearer.

FIG. 13 is a flow chart 1300 of a first method of wireless communication. The method may be performed by a UE, such as the UE 804. In step 1302, a UE receives system information (e. g. , SIB13) indicating an MCCH modification period in which an MSP can be changed–the MCCH modification period may be less than or equal to 5.12 seconds. In step 1304, the UE monitors MSI based on a first MSP. The UE monitors MSI by receiving and decoding the MSI once every MSP. In step 1306, the UE receives an MBMS service. The MBMS service may be a group communication associated with low latency. Information associated with the MBMS service may be included in the MSI (see FIG. 7B, an MSI MAC control element) . In step 1308, upon receiving the group communication, the UE receives an indication that the MSI should be monitored based on the second MSP rather than the first MSP. The indication may be an updated MBSFN area configuration message, which may be updated in the beginning of each MCCH modification period. In step 1310, the UE monitors the MSI based on a second MSP less than the first MSP upon receiving the MBMS service. In one example, the second MSP is 80 ms and the first MSP is greater than 80 ms.

FIG. 14 is a flow chart 1400 of a second method of wireless communication. The method may be performed by a UE, such as the UE 904. In step 1402, a UE receives a configuration for an MBMS bearer. Subsequently, in step 1404, even though an MBMS bearer is configured, the UE refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. In step 1406, the UE receives an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. In step 1408, the UE monitors the MSI for the particular PMCH upon receiving the group communication via the unicast bearer. The UE monitors MSI by receiving and decoding the MSI once every MSP. In step 1410, the UE receives a remaining part of the group communication via the MBMS bearer.

FIG. 15 is a flow chart 1500 of a third method of wireless communication. The method may be performed by a UE, such as the UE 1004. In step 1502, a UE receives system information (e. g. , SIB13) indicating an MCCH modification period in which an MSP for receiving MSI can be changed. The MCCH modification period may be less than or equal to 5.12 seconds. In step 1504, the UE receives an initial part of a group communication associated with low latency via a unicast bearer. In step 1506, the UE determines whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer. In step 1506, the UE may receive an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer. The UE may determine whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication. In step 1508, upon determining to receive the remaining part of the group communication via the MBMS bearer, the UE determines to monitor the MSI for a PMCH of the group communication after not having monitored the MSI for the PMCH. The UE monitors MSI by receiving and decoding the MSI once every MSP. In step 1510, the UE receives a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer. In step 1512, the UE receives the remaining part of the group communication via the MBMS bearer.

FIG. 16 is a flow chart 1600 of a fourth method of wireless communication. The method may be performed by a UE, such as the UE 1104. In step 1602, a UE receives an MSI change notification. In step 1604, the UE obtains MSI based on the received MSI change notification. In step 1602, the MSI change notification may include information associated with a TMGI, and in step 1604, the UE may obtain the MSI for a PMCH associated with the TMGI. In step 1606, the UE determines a group communication associated with low latency is scheduled based on the obtained MSI. In step 1606, the UE may determine the TMGI is for a group communication associated with low latency. In step 1608, the UE monitors the MSI periodically once every MSP upon determining the group communication is scheduled or upon determining the TMGI is for the group communication. The UE monitors MSI by receiving and decoding the MSI once every MSP. In step 1602, the MSI change notification may indicate which PMCHs have an MSI change, and in step 1604, the UE may obtain the MSI for each of the indicated PMCHs. In step 1602, the MSI change notification may be received together with an MCCH change notification in the same PDCCH. Alternatively, in step 1602, the MSI change notification and an MCCH change notification may be received separately in different PDCCHs.

FIG. 17 is a flow chart 1700 of a fifth method of wireless communication. The method may be performed by a UE, such as the UE 1204. In step 1702, a UE receives a configuration for an MBMS bearer. Subsequently, in step 1704, even though an MBMS bearer is configured, the UE refrains from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. In step 1706, the UE receives a paging message indicating a group communication associated with low latency. The group communication is associated with a particular PMCH. The paging message may be a unicast paging message or a group paging message. The paging message may include information associated with a TMGI. The TMGI is associated with the particular PMCH. In step 1708, the UE monitors the MSI for the particular PMCH upon receiving the paging message. The UE monitors MSI by receiving and decoding the MSI once every MSP. In step 1710, the UE obtains the MSI for the particular PMCH associated with the TMGI. In step 1712, the UE receives the group communication via the MBMS bearer.

FIG. 18 is a conceptual data flow diagram 1800 illustrating the data flow between different modules/means/components in an exemplary apparatus 1802. The apparatus may be a UE. The apparatus includes a receiving module 1804, an MBMS processing module 1806, and an MSI monitoring module 1808.

In a first configuration, the MSI monitoring module 1808 is configured to monitor MSI based on a first MSP. The receiving module 1804 is configured to receive an MBMS service from an eNB 1850. The MBMS service is a group communication associated with low latency. Information associated with the MBMS service is included in the MSI. The MSI monitoring module 1808 is further configured to monitor the MSI based on a second MSP less than the first MSP upon receiving the MBMS service. The receiving module 1804 may be further configured to receive, from the eNB 1850, an indication that the MSI should be monitored based on the second MSP rather than the first MSP upon receiving the group communication. The indication may be an MBSFN area configuration message. The receiving module 1804 may provide the MBSFN area configuration message to the MBMS processing module 1806 for processing of the message and for implementation of the updated MSP. The receiving module 1804 may be configured to receive, from the eNB 1850, system information indicating an MCCH modification period in which an MSP can be changed. The MCCH modification period may be less than or equal to 5.12 seconds. The receiving module 1804 may provide the system information to the MBMS processing module 1806 for processing and implementation. The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of FIG. 8. As such, each step in the aforementioned flow charts of FIG. 8 may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

In a second configuration, the MSI monitoring module 1808 is configured to refrain from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The receiving module 1804 is configured to receive an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. The MSI monitoring module 1808 is further configured to monitor the MSI for the particular PMCH upon receiving the group communication via the unicast bearer. The receiving module 1804 may be configured to receive a remaining part of the group communication via an MBMS bearer. The receiving module 1804 may be configured to receive a configuration for the MBMS bearer before refraining from monitoring the MSI. The receiving module 1804 may provide the configuration to the MBMS processing module 1806 for processing and implementation. The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of FIG. 9. As such, each step in the aforementioned flow charts of FIG. 9 may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

In a third configuration, the receiving module 1804 is configured to receive an initial part of a group communication associated with low latency via a unicast bearer. MBMS processing module 1806 is configured to determine whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer. Upon determining to receive the remaining part of the group communication via the MBMS bearer, the MBMS processing module 1806 is further configured to determine to monitor MSI for a PMCH of the group communication after not having monitored the MSI for the PMCH. The receiving module 1804 may be configured to receive an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer. The UE may determine whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication. The receiving module 1804 may be configured to receive a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer. The receiving module 1804 may be configured to receive the remaining part of the group communication via the MBMS bearer. The receiving module 1804 may be configured to receive system information indicating an MCCH modification period in which an MSP for receiving the MSI can be changed. The MCCH modification period may be less than or equal to 5.12 seconds. The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of FIG. 10. As such, each step in the aforementioned flow charts of FIG. 10 may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

In a fourth configuration, the receiving module 1804 is configured to receive an MSI change notification, and to obtain MSI based on the received MSI change notification. The MBMS processing module 1806 may be configured to determine a group communication associated with low latency is scheduled based on the obtained MSI. The MSI monitoring module 1808 may be configured to monitor the MSI periodically upon determining the group communication is scheduled. The MSI change notification may include information associated with a TMGI, and the UE may obtain the MSI for a PMCH associated with the TMGI. The MBMS processing module 1806 may be configured to determine the TMGI is for a group communication associated with low latency. The MSI monitoring module 1808 may be configured to monitor the MSI for the PMCH periodically upon determining the TMGI is for the group communication. The MSI change notification may indicate which MBSFNs have an MSI change, and the UE may obtain the MSI for each PMCH of the MBSFNs indicated in the MSI change notification. The MSI change notification may indicate which PMCHs have an MSI change, and the UE may obtain the MSI for each of the indicated PMCHs. The MSI change notification may be received together with an MCCH change notification in a same PDCCH. The MSI change notification and an MCCH change notification may be received separately in different PDCCHs. The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of FIG. 12. As such, each step in the aforementioned flow charts of FIG. 12 may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

In a fifth configuration, the MSI monitoring module 1808 is configured to refrain from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The receiving module 1804 is configured to receive a paging message indicating a group communication associated with low latency. The group communication is associated with a particular PMCH. The MSI monitoring module 1808 is further configured to monitor the MSI for the particular PMCH upon receiving the paging message. The paging message may be a unicast paging message or a group paging message. In one configuration, the paging message includes information associated with a TMGI, the TMGI is associated with the particular PMCH, and the receiving module 1804 is configured to obtain the MSI for the particular PMCH associated with the TMGI. The receiving module 1804 may be further configured to receive the group communication via an MBMS bearer. The receiving module 1804 may be further configured to receive a configuration for the MBMS bearer before refraining from monitoring the MSI. The apparatus may include additional modules that perform each of the steps of the algorithm in the aforementioned flow chart of FIG. 13. As such, each step in the aforementioned flow charts of FIG. 13 may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.

FIG. 19 is a diagram 1900 illustrating an example of a hardware implementation for an apparatus 1802'employing a processing system 1914. The processing system 1914 may be implemented with a bus architecture, represented generally by the bus 1924. The bus 1924 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1914 and the overall design constraints. The bus 1924 links together various circuits including one or more processors and/or hardware modules, represented by the processor 1904, the

modules

1804, 1806, 1808, and the computer-readable medium/memory 1906. The bus 1924 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system 1914 may be coupled to a transceiver 1910. The transceiver 1910 is coupled to one or more antennas 1920. The transceiver 1910 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 1910 receives a signal from the one or more antennas 1920, extracts information from the received signal, and provides the extracted information to the processing system 1914. In addition, the transceiver 1910 receives information from the processing system 1914, and based on the received information, generates a signal to be applied to the one or more antennas 1920. The processing system 1914 includes a processor 1904 coupled to a computer-readable medium/memory 1906. The processor 1904 is responsible for general processing, including the execution of software stored on the computer-readable medium/memory 1906. The software, when executed by the processor 1904, causes the processing system 1914 to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory 1906 may also be used for storing data that is manipulated by the processor 1904 when executing software. The processing system further includes at least one of the

modules

1804, 1806, 1808. The modules may be software modules running in the processor 1904, resident/stored in the computer readable medium/memory 1906, one or more hardware modules coupled to the processor 1904, or some combination thereof. The processing system 1914 may be a component of the UE 650 and may include the memory 660 and/or at least one of the TX processor 668, the RX processor 656, and the controller/processor 659.

In a first configuration, the apparatus 1802/1802'for wireless communication includes means for monitoring MSI based on a first MSP. The apparatus further includes means for receiving an MBMS service. The MBMS service is a group communication associated with low latency. Information associated with the MBMS service is included in the MSI. The apparatus further includes means for monitoring the MSI based on a second MSP less than the first MSP upon receiving the MBMS service. The apparatus may further include means for receiving an indication that the MSI should be monitored based on the second MSP rather than the first MSP upon receiving the group communication. The apparatus may further include means for receiving system information indicating an MCCH modification period in which an MSP can be changed. The MCCH modification period may be less than or equal to 5.12 seconds.

In a second configuration, the apparatus 1802/1802'for wireless communication includes means for refraining from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The apparatus further includes means for receiving an initial part of a group communication associated with low latency via a unicast bearer. The group communication is associated with a particular PMCH. The apparatus further includes means for monitoring the MSI for the particular PMCH upon receiving the group communication via the unicast bearer. The apparatus may further include means for receiving a remaining part of the group communication via an MBMS bearer. The apparatus may further include means for receiving a configuration for the MBMS bearer before refraining from monitoring the MSI.

In a third configuration, the apparatus 1802/1802'for wireless communication includes means for receiving an initial part of a group communication associated with low latency via a unicast bearer. The apparatus further includes means for determining whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer. The apparatus further includes means for determining to monitor MSI for a PMCH of the group communication after not having monitored the MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer. The apparatus may further include means for receiving an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer. The UE determines whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication. The apparatus may further include means for receiving a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer, and means for receiving the remaining part of the group communication via the MBMS bearer. The apparatus may further include means for receiving system information indicating an MCCH modification period in which an MSP for receiving the MSI can be changed. The MCCH modification period may be less than or equal to 5.12 seconds.

In a fourth configuration, the apparatus 1802/1802'for wireless communication includes means for receiving an MSI change notification, and means for obtaining MSI based on the received MSI change notification. The apparatus may further include means for determining a group communication associated with low latency is scheduled based on the obtained MSI, and means for monitoring the MSI periodically upon determining the group communication is scheduled. In one configuration, the MSI change notification includes information associated with a TMGI, and the UE obtains the MSI for a PMCH associated with the TMGI. In such a configuration, the apparatus may further include means for determining the TMGI is for a group communication associated with low latency, and means for monitoring the MSI for the PMCH periodically upon determining the TMGI is for the group communication.

In a fifth configuration, the apparatus 1802/1802'for wireless communication includes means for refraining from monitoring MSI for a PMCH when not receiving an MBMS service on the PMCH. The apparatus further includes means for receiving a paging message indicating a group communication associated with low latency. The group communication is associated with a particular PMCH. The apparatus further includes means for monitoring the MSI for the particular PMCH upon receiving the paging message. In one configuration, the paging message includes information associated with a TMGI, the TMGI is associated with the particular PMCH, and the apparatus further includes means for obtaining the MSI for the particular PMCH associated with the TMGI. The apparatus may further include means for receiving the group communication via an MBMS bearer. The apparatus may further include means for receiving a configuration for the MBMS bearer before refraining from monitoring the MSI.

The aforementioned means may be one or more of the aforementioned modules of the apparatus 1802 and/or the processing system 1914 of the apparatus 1802'configured to perform the functions recited by the aforementioned means. As described supra, the processing system 1914 may include the TX Processor 668, the RX Processor 656, and the controller/processor 659. As such, in one configuration, the aforementioned means may be the TX Processor 668, the RX Processor 656, and the controller/processor 659 configured to perform the functions recited by the aforementioned means.

It is understood that the specific order or hierarchy of steps in the processes/flow charts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes/flow charts may be rearranged. Further, some steps may be combined or omitted. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. ” Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “at least one of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “at least one of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

WHAT IS CLAIMED IS:

Claims

A method of wireless communication of a user equipment (UE) , comprising:

refraining from monitoring multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) when not receiving a Multimedia Broadcast Multicast Service (MBMS) service on the PMCH；

receiving an initial part of a group communication associated with low latency via a unicast bearer, the group communication being associated with a particular PMCH； and

monitoring the MSI for the particular PMCH upon receiving the group communication via the unicast bearer.
The method of claim 1, further comprising receiving a remaining part of the group communication via an MBMS bearer.
The method of claim 2, further comprising receiving a configuration for the MBMS bearer before refraining from monitoring the MSI.
A method of wireless communication of a user equipment (UE) , comprising:

receiving an initial part of a group communication associated with low latency via a unicast bearer；

determining whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer； and

determining to monitor multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) of the group communication after not having monitored the MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer.
The method of claim 4, further comprising receiving an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer, wherein the UE determines whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication.
The method of claim 5, further comprising:

receiving a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer； and

receiving the remaining part of the group communication via the MBMS bearer.
The method of claim 4, further comprising receiving system information indicating a multicast control channel (MCCH) modification period in which a MCH scheduling period (MSP) for receiving the MSI can be changed, wherein the MCCH modification period is less than or equal to 5.12 seconds.
An apparatus for wireless communication, the apparatus being a user equipment (UE) , comprising:

means for refraining from monitoring multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) when not receiving a Multimedia Broadcast Multicast Service (MBMS) service on the PMCH；

means for receiving an initial part of a group communication associated with low latency via a unicast bearer, the group communication being associated with a particular PMCH； and

means for monitoring the MSI for the particular PMCH upon receiving the group communication via the unicast bearer.
The apparatus of claim 8, further comprising means for receiving a remaining part of the group communication via an MBMS bearer.
The apparatus of claim 9, further comprising means for receiving a configuration for the MBMS bearer before refraining from monitoring the MSI.
An apparatus for wireless communication, the apparatus being a user equipment (UE) , comprising:

means for receiving an initial part of a group communication associated with low latency via a unicast bearer；

means for determining whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer； and

means for determining to monitor multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) of the group communication after not having monitored the MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer.
The apparatus of claim 11, further comprising means for receiving an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer, wherein the means for determining determines whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication.
The apparatus of claim 12, further comprising:

means for receiving a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer； and

means for receiving the remaining part of the group communication via the MBMS bearer.
The apparatus of claim 11, further comprising means for receiving system information indicating a multicast control channel (MCCH) modification period in which a MCH scheduling period (MSP) for receiving the MSI can be changed, wherein the MCCH modification period is less than or equal to 5.12 seconds.
An apparatus for wireless communication, the apparatus being a user equipment (UE) , comprising:

a memory； and

at least one processor coupled to the memory and configured to:

refrain from monitoring multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) when not receiving a Multimedia Broadcast Multicast Service (MBMS) service on the PMCH；

receive an initial part of a group communication associated with low latency via a unicast bearer, the group communication being associated with a particular PMCH； and

monitor the MSI for the particular PMCH upon receiving the group communication via the unicast bearer.
The apparatus of claim 15, wherein the at least one processor is further configured to receive a remaining part of the group communication via an MBMS bearer.
The apparatus of claim 16, wherein the at least one processor is further configured to receive a configuration for the MBMS bearer before refraining from monitoring the MSI.
An apparatus for wireless communication, the apparatus being a user equipment (UE) , comprising:

a memory； and

at least one processor coupled to the memory and configured to:

receive an initial part of a group communication associated with low latency via a unicast bearer；

determine whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer； and

determine to monitor multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) of the group communication after not having monitored the MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer.
The apparatus of claim 18, wherein the at least one processor is further configured to receive an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer, wherein the at least one processor is configured to determine whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer based on the indication.
The apparatus of claim 19, wherein the at least one processor is further configured to:

receive a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer； and

receive the remaining part of the group communication via the MBMS bearer.
The apparatus of claim 18, wherein the at least one processor is further configured to receive system information indicating a multicast control channel (MCCH) modification period in which a MCH scheduling period (MSP) for receiving the MSI can be changed, wherein the MCCH modification period is less than or equal to 5.12seconds.
A computer program product stored on a computer-readable medium and comprising code that when executed on at least one processor causes the at least one processor to:

refrain from monitoring multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) when not receiving a Multimedia Broadcast Multicast Service (MBMS) service on the PMCH；

receive an initial part of a group communication associated with low latency via a unicast bearer, the group communication being associated with a particular PMCH； and

monitor the MSI for the particular PMCH upon receiving the group communication via the unicast bearer.
The computer program product of claim 22, wherein the code, when executed on the at least one processor, causes the at least one processor to receive a remaining part of the group communication via an MBMS bearer.
The computer program product of claim 23, wherein the code, when executed on the at least one processor, causes the at least one processor to receive a configuration for the MBMS bearer before refraining from monitoring the MSI.
A computer program product stored on a computer-readable medium and comprising code that when executed on at least one processor causes the at least one processor to:

receive an initial part of a group communication associated with low latency via a unicast bearer；

determine whether to receive a remaining part of the group communication via the unicast bearer or an MBMS bearer； and

determine to monitor multicast channel (MCH) scheduling information (MSI) for a physical multicast channel (PMCH) of the group communication after not having monitored the MSI for the PMCH upon determining to receive the remaining part of the group communication via the MBMS bearer.
The computer program product of claim 25, wherein the code, when executed on the at least one processor, causes the at least one processor to receive an indication of whether the remaining part of the group communication should be received via the unicast bearer or the MBMS bearer, wherein the determination whether to receive the remaining part of the group communication via the unicast bearer or the MBMS bearer is based on the indication.
The computer program product of claim 26, wherein the code, when executed on the at least one processor, causes the at least one processor to:

receive a configuration for the MBMS bearer for receiving the remaining part of the group communication when the indication indicates that the remaining part of the group communication should be received via the MBMS bearer； and

receive the remaining part of the group communication via the MBMS bearer.
The computer program product of claim 25, wherein the code, when executed on the at least one processor, causes the at least one processor to receive system information indicating a multicast control channel (MCCH) modification period in which a MCH scheduling period (MSP) for receiving the MSI can be changed, wherein the MCCH modification period is less than or equal to 5.12 seconds.