WO2016176841A1

WO2016176841A1 - Fast transmission on repair packets with embms

Info

Publication number: WO2016176841A1
Application number: PCT/CN2015/078385
Authority: WO
Inventors: Xiaoxia Zhang; Peter Gaal; Xipeng Zhu; Jun Wang
Original assignee: Qualcomm Incorporated
Priority date: 2015-05-06
Filing date: 2015-05-06
Publication date: 2016-11-10

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may be a user equipment (UE). The apparatus receives at least one data packet of a multimedia broadcast multicast service (MBMS) session. The apparatus determines whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet. The apparatus transmits, when the MBMS data is unsuccessfully decoded, a session negative acknowledgement (NACK) response to indicate that the MBMS data is unsuccessfully decoded. The apparatus receives at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response.

Description

FAST TRANSMISSION ON REPAIR PACKETS WITH EMBMS

BACKGROUND Field

The present disclosure relates generally to communication systems, and more particularly, to a Multimedia Broadcast Multicast Service.

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 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 an aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a user equipment (UE) . The apparatus receives at least one data packet of a multimedia broadcast multicast service (MBMS) session. The apparatus determines whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet. The apparatus transmits, when the MBMS data is unsuccessfully decoded, a session negative acknowledgement (NACK) response to indicate that the MBMS data is unsuccessfully decoded. The apparatus receives at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response.

In an aspect of the disclosure, a method, a computer program product, and an apparatus are provided. The apparatus may be a base station. The base station transmits MBMS data of an MBMS session to a UE. The base station receives a session NACK response from the UE, where the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE. The base station transmits at least one repair packet to the UE based on the session NACK response.

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 (UE) 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. 8A is an example diagram illustrating communication between UEs and a network, according to a first option of the disclosure.

FIG. 8B is an example diagram illustrating communication between UEs and a network, according to a second option of the disclosure.

FIG. 8C is an example diagram illustrating communication between UEs and a network, according to a third option of the disclosure.

FIG. 9 is an example diagram illustrating data communication according to the first option of the disclosure.

FIG. 10 is an example diagram illustrating data communication according to the second option of the disclosure.

FIG. 11 is an example diagram illustrating data communication according to the third option of the disclosure.

FIG. 12 is a flowchart of a method of wireless communication, according to an aspect of the disclosure.

FIG. 13 is a flowchart of a method of wireless communication, expanding from the flowchart of FIG. 12, according to an aspect of the disclosure.

FIG. 14 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus.

FIG. 15 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.

FIG. 16 is a flowchart of a method of wireless communication, according to an aspect of the disclosure.

FIGs. 17A-17C are flowcharts of a method of wireless communication, expanding from the flowchart of FIG. 16, according to an aspect of the disclosure.

FIGs. 18A-18C are flowcharts of a method of wireless communication, expanding from the flowchart of FIG. 16, according to an aspect of the disclosure.

FIG. 19 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus.

FIG. 20 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, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

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 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, 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 a 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 contains 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 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 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 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 is 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 controller/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. 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' and 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 one or more 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. Initially, the UE may acquire a system information block (SIB) 13 (SIB13) . Subsequently, based on the SIB13, the UE may acquire an MBSFN Area Configuration message on an MCCH. Subsequently, based on the MBSFN Area Configuration message, the UE may acquire an MCH scheduling information (MSI) MAC control element. The SIB13 may include (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.

An HARQ process is generally available for unicast transmission to a UE. In particular, after the UE receives data (e.g., via unicast transmission) from a network (e.g., eNB) , the UE may provide an HARQ feedback response to the network, which may be either an ACK response or a NACK response. The UE sends an ACK response to the network if the UE successfully decodes the received data, and the UE sends a NACK response to the network if the UE does not successfully decode the received data. If the UE sends the NACK response to the network, the network may retransmit the data to the UE, such that the UE may attempt to decode the data again. It is noted that the HARQ feedback may take place at a physical layer (e.g., between a physical layer of the UE and a physical layer of the eNB) . Thus, the turn-around time elapsed during the NACK response and the retransmission in the HARQ process is generally short (e.g., approximately 8ms) .

The HARQ feedback is generally not available for broadcast transmission via an MBMS service. Instead, when data is transmitted via the MBMS service, the UE may send a reception report to the network at the end of each session, where a decoding status of received data is included in the reception report. For example, even if a UE determines in the middle of a session that a packet is not decoded, the UE waits until the session is over and then sends the reception report to the network at the end of the session. In such an example, the UE may need additional redundancy of data (e.g., repair packets) to successfully decode the original session. Hence, if the reception report indicates that a data packet is not decoded, the network may send the repair packets in response to the reception report. The network may transmit the repair packets to the UE via a unicast transmission or via a broadcast transmission via the MBMS service. However, this approach may cause undesirable delay. For example, if a UE is in an idle mode at the end of the session and the reception report indicates that the data is not decoded, the UE will change to a connected mode to receive retransmission of data or to receive repair packets. The transition to the connected mode can be time-consuming. Further, the reception report is communicated via an application layer, which may cause more delay than communication via a lower layer such as a physical layer. Therefore, although the UE may rely on the reception report to recover from packet loss by receiving additional packets, such a process can be slow and may not be desirable for delay-sensitive MBMS applications.

In addition, the HARQ feedback feature for MBMS broadcast transmission may be difficult to provide at least for the following reasons. Because HARQ feedback is generally provided by each UE individually, a large number of resources may need to be allocated for the HARQ feedback (ACK/NACK response) . For example, if there are 100 UEs receiving the same service, then 100 resources should be allocated for the ACK/NACK response from each of the respective 100 UEs. When utilizing a group NACK feedback feature where any UE that cannot decode a packet can send the NACK response on the same resource, a network node (e.g., an eNB) may retransmit each packet as long as at least one of the UEs cannot decode the packet. Further, all UEs should transition to a connected mode, if not in connected mode, to provide the ACK/NACK response. Therefore, an approach with a fast UE response and reduced overhead is desired to provide feedback on reception/decoding of data delivered via MBMS broadcast transmission, and to help the UE successfully decode the data.

According to an aspect of the disclosure, when a UE receives a broadcast transmission of data packets carrying MBMS data during an MBMS session of a MBMS service, the UE may provide feedback by sending a session ACK/NACK response (referred to herein as a session ACK/NACK) to the network (e.g., eNB) in order to indicate the decoding status of MBMS data of an MBMS session after the session ends, instead of using a reception report. In particular, the UE attempts to decode the MBMS data based on the data packets received during the MBMS session, and provides a session ACK/NACK response to indicate whether the UE has successfully decoded the MBMS data of the MBMS session. In an aspect, the UE may utilize an HARQ feedback feature to send a session ACK/NACK response. Because the UE in this aspect of the disclosure utilizes a lower layer (e.g., a physical layer) to transmit the session ACK/NACK response, resource consumption may be lower than an approach utilizing an upper layer (e.g., application layer) , and a delay in communication may be reduced. In particular, when an MBMS session ends, the UE transmits a session ACK/NACK response in the physical layer of the UE, and the eNB receives the session ACK/NACK response in the physical layer of the eNB. If the UE has not successfully decoded the MBMS data of the MBMS session, the UE sends a session NACK response to the eNB at the end of the MBMS session. Thus, the session NACK response may indicate to the eNB that the MBMS data of the MBMS session is not successfully decoded by a UE. When the eNB receives the session NACK response, the eNB sends at least one repair packet to the UE, such that the UE may attempt to decode the MBMS data using the repair packet and the data packet (s) received during the MBMS session. If the UE still cannot successfully decode the MBMS data using the repair packet and the data packet, the UE sends another session NACK response, such that the eNB sends one or more additional repair packets to the UE. The process of the UE receiving repair packets and sending a NACK response in response to failing to decode the MBMS data may be repeated until the UE can successfully decode the MBMS data based on received data packets and received repair packets.

The UE may enter into an RRC connected mode to be able to receive the at least one repair packet from the eNB. Thus, at the end of the MBMS session, if the UE has not received sufficient packets to decode MBMS data of the MBMS session and is not in the RRC connected mode (e.g., the UE is in an idle mode) , the UE goes into the RRC connected mode to receive the repair packets. The UEs that are already able to successfully decode the MBMS data of the MBMS session may stay in the idle mode if the UE is already in the idle mode. The eNB may send, to the UE, packet information on how many packets are sufficient for session decoding, such that the UE may determine whether the UE has received a sufficient number of packets for decoding. Thus, for example, if the UE determines based on the packet information that the UE has not received a sufficient number of packets to decode the MBMS data of the MBMS session, the UE may send a session NACK response to the network. In one example, if the packet information indicates that 100 packets are sufficient for session decoding and the UE has received 80 packets, the UE determines based on the packet information that the UE has not received sufficient packets to decode the MBMS data of the MBMS session, and may determine that 20 more packets are needed for successful decoding. In such an example, if the UE receives 20 more packets (e.g., by receiving 20 repair packets) , the UE may determine that a sufficient number of packets are received for decoding.

Each of the UEs that cannot decode the MBMS data may send a session NACK response to the eNB using a pre-defined location of resources (e.g., based on allocation of the ACK/NACK resources, as discussed infra) . It is noted that one resource may be shared among multiple UEs to send a session NACK response, and another resource may be shared among multiple UEs to send a session ACK response. According to an aspect, one resource may be used for the session NACK response such that each of the UEs that cannot decode the MBMS data uses one resource to transmit a session NACK response to the network. Each of the UEs that can successfully decode the MBMS data may use another resource to transmit a session ACK response to the network. In an aspect, UEs that can decode the MBMS data may not transmit session ACK responses, while UEs that cannot decode the MBMS data transmit session NACK responses. Thus, in this aspect, if the network does not receive any session NACK response from at least one UE, the network may determine that the UEs have successfully decoded the MBMS data. It is noted that if one UE transmits a session NACK response and another UE transmits a session ACK response, one resource is used for the session NACK response and another resource is used for the session ACK response, and thus two resources are used. On the other hand, if UEs are configured to refrain from sending session ACK responses, one resource is used for session NACK responses and no resource is used for session ACK responses, and thus only one resource is used.

In one aspect, allocation of the ACK/NACK resources may be indicated in an MBMS control signal (e.g., via information indicated on an MCCH or in MSI) . Because UL transmission is performed via unicast transmission, the resource assignments for ACK/NACK among different eNBs may not be the same. Thus, if the ACK/NACK resource is indicated by each eNB separately, the ACK/NACK resource allocation may be different among different eNBs. However, according to this aspect of the disclosure, in a case where the ACK/NACK resource is indicated in an MCCH or in MSI, all eNBs in the MBSFN transmit the same content simultaneously in order to maintain MBSFN gain. Hence, in such a case, the ACK/NACK resource assignments among different eNBs are coordinated so that the ACK/NACK resource assignments are identical among different eNBs. Thus, if the allocation of the ACK/NACK resources is indicated in the MCCH or the MSI, then the ACK/NACK resources should be common for all eNBs in the same MBSFN area (e.g., to benefit from an optimal MBSFN gain) . Thus, all eNBs in the same MBSFN area may coordinate with one another, and assign the same ACK/NACK resources that may be shared among the eNBs in the same MBSFN area. Therefore, the coordinated eNBs in the same MBSFN area may communicate the same signals to the UE using the same ACK/NACK resources. In another aspect, each eNB may assign a specific ACK/NACK resource per eNB.

For an ACK/NACK response, a single resource or multiple resources may be allocated per session. As discussed supra, the UE may determine based on the packet information received from the eNB whether sufficient packets are received for decoding, where the packet information indicates a number of packets sufficient for session decoding. Thus, based on the packet information and the number of data packets received by the UE, the UE may determine a number of repair packets needed for decoding the MBMS data of the session. The number of resources allocated per session can be used to by a UE to signal the number of repair packets needed to decode the MBMS data of the session. If a single resource is allocated for a NACK response, the single NACK response may indicate a single number or a single range of additional repair packets. If multiple resources are allocated per session for the NACK response, each resource may represent a different number or a different range of additional repair packets for decoding the MBMS data. In an aspect, based on the location of the resource where a NACK response is received, an eNB may determine how many repair packets to send to the UE. For example, if there are four resources (first through fourth resources) , a first resource may correspond to 0％ to 25％ of the number of packets sufficient for decoding, a second resource may correspond to 25％ to 50％ of the number of packets sufficient for decoding, a third resource may correspond to 50％ to 75％ of the number of packets sufficient for decoding, and a fourth resource may correspond to 75％ to 100％ of the number of packets sufficient for decoding. Thus, UEs that need less than 25％ of the number of packets sufficient for decoding may send a NACK response on the first resource, UEs that need more than 25％ but less than 50％ of the number of packets sufficient for decoding may send NACK on the second resource, and so on. In this example, if the packet information indicates that 100 data packets are needed for decoding and the UE initially receives 80 data packets, the UE needs to receive 20 additional (repair) packets, which is 20％ of 100 data packets needed for decoding. Thus, in this example, because the UE needs to receive 20％ of the number of packets sufficient for decoding, the UE may send a NACK response using the first resource corresponding to correspond to 0％ to 25％.

The eNB may compare a number of the NACK responses in each resource for the NACK response, and determine a number of repair packets to send to the UEs based on the comparison. For example, if the eNB determines that the number of NACK responses received on the second resource is greater than the number of NACK responses received on the first resource, eNB may determine that more than 25％ but less than 50％ of the number of packets sufficient for decoding should be sent because the second resource corresponds to 25％-50％ . In an aspect, a resource for a NACK response may be assigned per eNB.

The UE may send a NACK response in an idle mode or in an RRC connected mode. However, the UE may need to be in the RRC connected mode to receive repair packets. Thus, when an MBMS session ends, the UE may transition from an idle mode to an RRC connected mode (e.g., to receive repair packets) , and such transition may take some time. In order to allow time for the UE to make such transition to the RRC connected mode, the UE may transmit a NACK response some time after the MBMS session ends (e.g., approximately 100ms after the MBMS session ends) .

As discussed above, when the eNB receives a NACK response from the UE, the eNB sends additional repair packets to the UE via a unicast transmission or via a broadcast transmission (e.g., using the MBMS service) . The repair packets may be transferred from a BM-SC to the eNB or may be generated at the eNB. According to one aspect, the eNB may receive the repair packets from a BM-SC (e.g., the BM-SC 126) such that the eNB may send the repair packets to the UE. The BM-SC may send sufficient repair packets (e.g., all possible repair packets) to eNB via a backhaul connection. Subsequently, out of the repair packets received from the BM-SC, the eNB may send a specific number of repair packets to the UE, wherein the specific number of repair packets may be determined by the eNB. The eNB may receive the repair packets from the BM-SC via an M1 interface. According to another aspect, the BM-SC may send FEC parameters (e.g., application layer FEC parameters) to the eNB, and the eNB may generate the repair packets based on the FEC parameters. The BM-SC may send sufficient FEC parameters for all possible repair packets to the eNB.

Several options may be implemented for transmission of the repair packets from the eNB to the UE. According to a first option, the eNB transmits repair packets to the UE via a unicast transmission when the eNB receives a session NACK response. Because a unicast transmission is used to transmit repair packets, coordination among eNBs in the MBSFN area may not be necessary for the transmission of the repair packets. According to the first option, the eNB transmits repair packets to each UE individually via a dedicated unicast transmission when the eNB receives session NACK responses from these UEs. For example, if 100 UEs send session NACK responses to the eNB to indicate the need for repair packets, the eNB performs 100 unicast transmissions of the repair packets to the 100 UEs, one dedicated unicast transmission per UE, respectively. Thus, the eNB may transmit the same repair packets individually to each of multiple UEs on a one by one basis via dedicated unicast transmissions.

FIG. 8A is an example diagram 800 illustrating communication between UEs and a network, according to a first option of the disclosure. The example diagram 800 shows a first UE 802, a second UE 804, and a third UE 806 capable of communicating with a first eNB 812, a second eNB 814, and a third eNB 816 that belong to an original MBSFN 810. At 820, the first, second, and

third eNBs

812, 814, and 816 transmit MBMS data of an MBMS session via broadcast transmission using the original MBSFN 810. Thus, the original MBSFN 810 is the MBSFN that initially transmits the MBMS data of the MBMS session. The first UE 802 sends at 822 a session NACK response to the second eNB 814, and the second UE 804 sends at 824 a session NACK response to the second eNB 814, because the first UE 802 and the second UE 804 fail to decode the MBMS data correctly. The third UE 806 does not send a session NACK response because the third UE 806 has successfully decoded the MBMS data. In response to the session NACK responses, the second eNB 814 sends at 826 repair packets via a unicast transmission to the first UE 802, and sends at 828 repair packets via another unicast transmission to the second UE 804. The first and

second UEs

802 and 804 may attempt to decode the MBMS data using the received repair packets.

According to a second option, the eNB transmits the repair packets via broadcast transmission using a small MBSFN or via a group bearer. Because the eNB according to the second option utilizes the broadcast transmission, the repair packets may be received by multiple UEs simultaneously. For example, if an UE in the small MBSFN area does not decode the MBMS data, the small MBSFN may transmit repair packets to UEs within the small MBSFN via broadcast transmission. The small MBSFN is an MBSFN that covers a smaller area than an original MBSFN that initially transmits the MBMS data of the MBMS session. For example, the small MBSFN may have a smaller number of eNBs than the original MBSFN. Thus, the small MBSFN may provide more limited MBSFN gain than the original MBSFN. In the small MBSFN, there is no or little coordination time between the eNBs within the small MBSFN, and thus utilizing the small MBSFN for broadcast transmission does not cause more delay than utilizing unicast transmission. It is noted that the small MBSFN may be pre-defined (e.g., based on a backhaul latency) . For example, cells in the original MBSFN that have same or similar backhaul latencies may be grouped together to form the small MBSFN. In one aspect, the small MBSFN may be a single site MBSFN. The single site MBSFN may include a single eNB or multiple eNBs. If the single site MBSFN includes multiple eNBs, these eNBs are synchronized such that the eNBs may transmit the same data in a synchronized manner. Further, a group bearer utilizes a single cell or a smaller group of cells than the original MBSFN to send a broadcast transmission to the UE.

Hence, according to the second option, the eNB may utilize a small MBSFN and/or a group bearer to transmit repair packets to UEs via broadcast transmission, instead of establishing a unicast connection to each of the UEs to transmit the same packets to each of the UEs via unicast transmission. For example, according to the second option, the MBMS data of the MBMS session may be transmitted to the UE via broadcast transmission using the original MBSFN, and if the eNB receives a session NACK response from the UE, the eNB may transmit the repair packets via a small MBSFN or via a group bearer. When the UE cannot decode the MBMS data, the UE may utilize the HARQ feedback feature to transmit a session NACK response, such that the eNB may transmit the repair packets to the UE based on the session NACK response.

FIG. 8B is an example diagram 830 illustrating communication between UEs and a network, according to a second option of the disclosure. The example diagram 830 shows a first UE 832, a second UE 834, and a third UE 836 capable of communicating with a first eNB 842, a second eNB 844, and a third eNB 846 that belong to an original MBSFN 840. At 850, the first, second, and

third eNBs

842, 844, and 846 transmit MBMS data of an MBMS session via broadcast transmission using the original MBSFN 840. The first UE 832 sends at 852 a session NACK response to the second eNB 844, and the second UE 834 sends at 854 a session NACK response to the second eNB 844, because the first UE 832 and the second UE 834 fail to decode the MBMS data correctly. The third UE 836 does not send a session NACK response because the third UE 836 has successfully decoded the MBMS data. In response to the session NACK responses, the second eNB 844 sends at 856 repair packets via broadcast transmission using the single site MBSFN 845 that is served by the second eNB 844. The first UE 832 and the second UE 834 may receive the broadcast transmission of the repair packets, and attempt to decode the MBMS data using the repair packets.

In the second option, the UE may continue to send a session NACK response as long as the UE cannot decode the MBMS data after the MBMS session ends and/or after receiving the repair packets. In particular, after the MBMS session ends, the eNB may determine a number of repair packets to be sent to the UE when the session NACK response is received after the MBMS session ends. In an aspect, instead of transmitting all of the repair packets in a single transmission, the eNB may transmit the repair packets in smaller increments over several transmissions to the UE. The UE may send a session ACK/NACK response each time the UE receives repair packets, and the eNB may stop transmitting the repair packets when the UE successfully decodes the MBMS data (as indicated by a session ACK response or lack of a session NACK response) . Therefore, the eNB may dynamically determine whether to transmit repair packets according to this aspect of the second option. For example, if the eNB determines at the end of the MBMS session that 100 repair packets should be sent, instead of transmitting 100 repair packets in a single transmission, the eNB may send 10 repair packets per transmission whenever the eNB receives a session NACK response. Thus, if the eNB receives a session NACK response, the eNB transmits 10 repair packets. If the eNB receives another session NACK response after transmitting the 10 repair packets, the eNB transmits another 10 repair packets. The eNB may continue to transmit 10 repair packets whenever the eNB receives a session NACK response, until the eNB stops receiving a session NACK response (or receives a session ACK response) .

In an aspect of the second option, the eNB may configure the UE to send a session ACK/NACK response with a response periodicity that is based on statistics of session ACK/NACK reception. The eNB may send a response periodicity to the UE such that the UE may send a session ACK/NACK response based on the response periodicity. For example, if all or many of the UEs need a lot of repair packets (e.g., more than 50％ of the number of packets sufficient for decoding) , it may take some time until the UEs receive sufficient repair packets to start being able to decode the MBMS data. Thus, in a case where all or many of the UEs need a lot of repair packets, the eNB may configure the response periodicity to a long periodicity such that the UEs may not send a session NACK for a predetermined time period based on the response periodicity even when the UEs cannot decode. On the contrary, if all or many of the UEs need fewer repair packets (e.g., less than 50％ of the number of packets sufficient for decoding the MBMS data) , then the eNB may configure the response periodicity to a short periodicity. Thus, the UE configured with a long response periodicity refrains from sending a session NACK for a longer period of time than the UE configured with a short response periodicity. The response periodicity may be configured based on the number of repair packets to be sent to the UE. In particular, the response periodicity may correspond to the estimated time for transmitting the total repair packets sufficient for decoding the MBMS data. For example, if the UE needs 40 additional packets to decode the MBMS data, the eNB may configure the response periodicity to correspond to the estimated time for transmitting 40 repair packets to the UE. It is noted that the eNB may change the response periodicity over time. For example, at the end of the MBMS session, many UEs may send NACK responses to indicate that the MBMS data is not decoded, and thus the eNB may set the response periodicity to long. However, as more repair packets are transmitted to the UEs, less UEs may send NACK responses, and thus the eNB may set the response periodicity to short later in time such that the eNB may send a session NACK more frequently.

According to an aspect of the second option, in addition to a resource allocated for a session NACK response, another resource may be allocated for the UEs to send a NACK response (e.g., a packet NACK response) for each individual repair packet. Thus, the UE may use a UL resource to send a session NACK response, and may use a different UL resource to send a packet NACK response. The UL resource used to indicate a session NACK and the UL resource used to indicate a packet NACK are different from each other so that the eNB may decode the session NACK response and the packet NACK response using the respective UL resources. Unlike a session NACK response that indicates that a session (e.g., the MBMS data of the session) is not decoded, a packet NACK response may indicate that a particular individual packet is not decoded. When the eNB receives a packet NACK response in response to a particular packet not being decoded, the eNB may retransmit a repair packet corresponding to the particular packet. With the multiple transmissions of the same packet, the UE may combine multiple transmissions of the particular packet to benefit from an HARQ gain. Hence, in this aspect of the second option, there are two levels of ACK/NACK responses, where a session ACK/NACK response indicates whether a session is decoded, and a packet ACK/NACK response indicates whether a particular packet is decoded.

After the eNB transmits repair packets to the UE, the UE may send a session ACK/NACK and/or a packet ACK/NACK. If the UE successfully decodes the repair packets received from the eNB but still cannot decode the session, the UE may only send a session NACK, and may not send a packet NACK. If the UE cannot decode the repair packets and cannot decode the session, then the UE may send both a session NACK and a packet NACK. In an aspect, if the UE can successfully decode the session after receiving repair packets, the UE may send a session ACK response, in order to indicate the successful session decoding, using a resource that is separate from the resource used to send a session NACK response. In an aspect, regardless of whether the UE can successfully decode the session after receiving repair packets, if the UE can decode the repair packets, the UE may also send a packet ACK in a resource that is separate from the resource used to send a packet NACK.

Because the second option utilizes a small MBSFN, there may be little or no time required for coordination among the eNBs compared to the original MBSFN that may take additional time to coordinate the transmissions from the eNBs. When a single site MBSFN is utilized for transmission of the repair packets, no eNB coordination may be needed because only one site of the original MBSFN is used for transmission. Because no or little eNB coordination time is needed for the second option, an HARQ timeline is not delayed by eNB coordination and thus can be maintained the same as for a unicast transmission timeline. Hence, the unicast timeline may be used for retransmission of the repair packets by the eNB. Because the unicast transmission timeline may be maintained, features generally available for the unicast transmission timeline may be utilized for the second option although the small MBSFN or the group bearer according to the second option utilizes broadcast transmission. For example, a buffer size requirement may depend on a transmission time line because a broadcast transmission time line may need a larger buffer size than the unicast transmission time line due to eNB coordination time for eNBs within an MBSFN. However, in the second option, because no or little eNB coordination time is needed for a small MBSFN or a group bearer, the buffer size requirement for the unicast transmission timeline may be utilized for the second option. It is noted that, in one aspect, memory used to store log likelihood ratios (LLRs) for repair packets in HARQ feedback (e.g., an ACK/NACK response) may reduce a size of a soft buffer available for unicast transmission. In an alternative aspect, the eNB may send several retransmissions back-to-back without waiting for HARQ feedback from the UE. If the eNB sends retransmissions of the repair packets without waiting for HARQ feedback, the HARQ feedback feature does not use memory to store LLRs for the repair packets, thus minimizing the impact on the size of the soft buffer.

In an aspect of the second option, the eNB may enable a packet ACK/NACK response based on statistics of session ACK/NACK reception. For example, if the eNB receives many session NACK responses, utilizing a packet ACK/NACK response may not be desirable because even if a UE decodes a packet correctly, the UE may still not be able to decode the MBMS data of the session, and thus may still send a session NACK response. When the eNB starts receiving less session NACK responses (e.g., because more UEs correctly decode the MBMS data of the session) , the eNB may enable a packet ACK/NACK response. In another aspect, the UE may determine not to send a session ACK/NACK response if the UE determines to send a packet ACK/NACK response. Further, the UE may not send a packet ACK/NACK response if the UE has sufficient packets to decode the session. It is further noted that when the MBSFN subframes allocated for MBSFN transmission of a particular MBMS service is not used, the MBSFN subframes may be used for other MBMS services or may be used for unicast transmission.

According to a third option of the disclosure, the eNB transmits the repair packets via broadcast transmission using the original MBSFN that is initially used to transmit the MBMS data of the MBMS session. Because the original MBSFN with multiple cells is used, all eNBs in the original MBSFN are coordinated for synchronized transmission of the repair packets. The HARQ feedback feature may not be utilized to transmit the repair packets in the third option because it takes some time for the eNBs in the original MBSFN to coordinate with each other for transmission of the repair packets, which causes a delay. For example, if an eNB receives a NACK response (e.g., a session NACK response) from a UE and determines to transmit repair packets to the UE, the eNB signals other eNBs in the same MBSFN (e.g., the original MBSFN) to coordinate transmission of the repair packets. In one aspect, the eNB may signal the other eNBs in the same MBSFN via an X2 interface to coordinate the transmission. In another aspect, eNBs in the same MBSFN may send a NACK status (according to a session NACK response) to an MCE, and the eNBs may receive, from the MCE, information on how to transmit the repair packets to the UE. The information on how to transmit the repair packets may include information on the number of repair packets to send, and which repair packets to send. In the third option, the UE may transmit a session ACK/NACK response, but may not transmit a packet ACK/NACK response. It is also noted that when the MBSFN subframes allocated for MBSFN transmission of a particular MBMS service is not used, the MBSFN subframes may be used for other MBMS services or may be used for unicast transmission.

FIG. 8C is an example diagram 860 illustrating communication between UEs and a network, according to a third option of the disclosure. The example diagram 860 shows a first UE 862, a second UE 864, and a third UE 866 capable of communicating with a first eNB 872, a second eNB 874, and a third eNB 876 that belong to an original MBSFN 870. At 880, the first, second, and

third eNBs

872, 874, and 876 transmit MBMS data of an MBMS session via broadcast transmission using the original MBSFN 870. The first UE 862 sends at 882 a session NACK response to the second eNB 874, and the second UE 864 sends at 884 a session NACK response to the second eNB 874, because the first UE 862 and the second UE 864 fail to decode the MBMS data correctly. The third UE 866 does not send a session NACK response because the third UE 866 has successfully decoded the MBMS data. In response to the session NACK responses, the first, second, and

third eNBs

872, 874, and 876 coordinate with one another to transmit at 886 repair packets via broadcast transmission using the original MBSFN 870. The first UE 832 and the second UE 834 may receive the broadcast transmission of the repair packets, and attempt to decode the MBMS data using the repair packets.

In the third option, a particular UE may continue to send a session NACK response as long as that UE cannot decode the MBMS data after the MBMS session ends. In particular, after the MBMS session ends, the eNB may determine a number of repair packets to be sent to the UE when the eNB receives the session NACK response sent by the UE after the MBMS session ends. Because the original MBSFN with multiple cells is used for transmission of the repair packets in the third option, the eNB may transmit the entire repair packets in a single transmission/session. In particular, after the MBMS session ends, the eNB may determine a number of repair packets to be sent to the UE if the session NACK response is received at the end of the MBMS session, and may transmit the repair packets based on the determined number of repair packets at once. If the UE still cannot decode the MBMS data using the received repair packets, the UE may transmit another NACK response to the eNB, such that the eNB may transmit additional repair packets to the UE.

In the third option, the eNB may configure the UE to send a session NACK response with a response periodicity that is based on statistics of session ACK/NACK reception. For example, if all or many of the UEs need a lot of repair packets (e.g., more than 50％ of the number of packets sufficient for decoding) , it may take some time until the UEs receive sufficient repair packets to start being able to decode the MBMS data. The consideration of the response periodicity for the third option may be similar to the consideration of the response periodicity for the second option, as discussed supra, and thus detailed explanations are omitted for brevity.

FIG. 9 is an example diagram 900 illustrating data communication according to the first option of the disclosure. MBMS data of an MBMS session is transmitted to a UE via broadcast transmission using the MBSFN frames such as MBSFN frames 912 and 914. When the MBMS session ends, the UE is signaled (e.g., via a session end message indicating that the session has ended) at 916 that the MBMS session has ended. If the UE determines at the end of the MBMS session that the UE cannot decode the MBMS data correctly, an RRC connection setup is performed at 922 to establish a unicast connection with an eNB. Using a UL subframe 932, the UE transmits at 934 a session NACK response to the eNB via UL transmission if the UE fails to decode the MBMS data correctly. The eNB transmits at 946 repair packets to the UE using one of the

unicast subframes

942 and 944 via unicast transmission in response to the session NACK response. The UE attempts to decode the MBMS data using the repair packets. If the UE still cannot decode the MBMS data correctly, the UE uses a UL subframe 952 to transmit at 954 a subsequent session NACK response to the eNB via UL transmission. The process of the UE receiving the repair packets and transmitting a session NACK response if the MBMS data is not decoded may be repeated until the MBMS data is correctly decoded, although such repetition of the process is not illustrated in FIG. 9.

FIG. 10 is an example diagram 1000 illustrating data communication according to the second option of the disclosure. MBMS data of an MBMS session is transmitted to a UE via broadcast transmission using the MBSFN frames such as MBSFN frames 1012 and 1014. When the MBMS session ends, the UE is signaled (e.g., via a session end message indicating that the session has ended) at 1016 that the MBMS session has ended. If the UE determines at the end of the MBMS session that the UE cannot decode the MBMS data correctly, an RRC connection setup is performed at 1022 to establish a unicast connection with an eNB. The UE transmits at 1034 a session NACK response to an eNB via UL transmission if the UE fails to decode the MBMS data correctly. In the second option, a single site MBSFN subframe or a group bearer subframe may be used to transmit repair packets via broadcast transmission. The eNB allocates certain subframes for a small MBSFN or a group bearer for transmission of repair packets. Using one of the single site MBSFN subframes (or group bearer subframes) 1042 and 1044, the eNB transmits at 1046 repair packets to the UE via broadcast transmission in response to the session NACK response. The UE attempts to decode the MBMS data using the repair packets. If the UE still cannot decode the MBMS data correctly, the UE uses a UL subframe 1052 to transmit at 1054 a subsequent session NACK response to the eNB via UL transmission. The UE may also use a UL subframe 1052 to transmit at 1056 a packet NACK response to the eNB via UL transmission if the repair packets are not decoded successfully (and thus MBMS data is also not decoded successfully) . The process of the UE receiving the repair packets and transmitting a session NACK response and/or a packet NACK response if the MBMS data is not decoded may be repeated until the MBMS data is correctly decoded, although such repetition of the process is not illustrated in FIG. 10.

FIG. 11 is an example diagram 1100 illustrating data communication according to the third option of the disclosure. MBMS data of an MBMS session is transmitted to a UE via broadcast transmission using the MBSFN frames for an original MBSFN such as MBSFN frames 1112 and 1114. When the MBMS session ends, the UE is signaled (e.g., via a session end message indicating that the session has ended) at 1116 that the MBMS session has ended. If the UE determines at the end of the MBMS session that the UE cannot decode the MBMS data correctly, an RRC connection setup is performed at 1122 to establish a unicast connection with an eNB. The UE transmits at 1134 a session NACK response to the eNB via an UL transmission using UL subframe 1132 if the UE fails to decode the MBMS data correctly. Using one of the

MBSFN subframes

1142 and 1144 for the original MBSFN, the eNB transmits at 1146 repair packets to the UE via broadcast transmission in response to the session NACK response. The UE attempts to decode the MBMS data using the repair packets. If the UE still cannot decode the MBMS data correctly, the UE transmits at 1154 a subsequent session NACK response to the eNB via an UL transmission using UL subframe 1152. The process of the UE receiving the repair packets and transmitting a session NACK response if the MBMS data is not decoded may be repeated until the MBMS data is correctly decoded, although such repetition of the process is not illustrated in FIG. 11.

FIG. 12 is a flowchart 1200 of a method of wireless communication, according to an aspect of the disclosure. The method may be performed by a UE (e.g., the

UE

804, 834, 864, the apparatus 1402/1402') . At 1202, the UE receives at least one data packet of an MBMS session. At 1204, the UE determines whether the MBMS data of the MBMS session can be successfully decoded based on the received at least one data packet. In an aspect, the UE may determine whether the MBMS data can be successfully decoded by determining whether a sufficient number of packets for decoding the MBMS data are received. Features 1206-1212 are performed if the UE determines that the MBMS data is unsuccessfully decoded (e.g., the MBMS data cannot be decoded) . At 1206, the UE transmits, when the MBMS data is unsuccessfully decoded, a session NACK response to indicate that the MBMS data is unsuccessfully decoded. In an aspect, the session NACK response may be an HARQ feedback response. In an aspect, the session NACK response may be transmitted via a physical layer. At 1208, the UE may enter into an RRC connected mode (e.g., to establish a unicast connection) to receive the at least one repair packet when the MBMS data is unsuccessfully decoded and the UE is in an RRC idle mode. At 1210, the UE receives at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response. At 1212, the UE may perform additional features, as discussed infra.

For example, as discussed supra, if the UE has not successfully decoded the MBMS data of the MBMS session, the UE sends a session NACK response to the eNB at the end of the MBMS session. For example, as discussed supra, when the eNB receives the session NACK response, the eNB sends repair packets to the UE, such that the UE may attempt to decode the MBMS data using the repair packets and the data packets received during the MBMS session. For example, as discussed supra, the UE may enter into an RRC connected mode to be able to receive the repair packets from the eNB. For example, as discussed supra, the UE utilizes a lower layer (e.g., a physical layer) to transmit the session ACK/NACK response. For example, as discussed supra, the UE may utilize an HARQ feedback feature to send a session ACK/NACK response.

Features in 1214 may be performed if the UE determines that the UE has successfully decoded the MBMS data. At 1214, the UE may refrain from transmitting, when the MBMS data is successfully decoded, a session ACK response to indicate that the MBMS data is successfully decoded.

For example, as discussed supra, the UEs that are already able to decode the MBMS data of the MBMS session may stay in the idle mode if the UE is already in the idle mode. For example, as discussed supra, UEs that can decode the MBMS data may not transmit session ACK responses.

In an aspect, the session NACK response is sent via a resource shared among a plurality of UEs to transmit session NACK responses. In such an aspect, the resource is indicated in at least one of an MCCH or MSI. In such an aspect, the resource comprises a plurality of resources, and each of the plurality of resources is assigned for a respective amount of repair packets for decoding the MBMS data. In such an aspect, the resource is shared among a plurality of base stations or is assigned to a specific base station.

For example, as discussed supra, allocation of the ACK/NACK resources may be indicated in an MBMS control signal (such as an MCCH or MSI) . For example, as discussed supra, if multiple resources are allocated per session for the NACK response, each resource may represent a different level of a number of additional repair packets for decoding the MBMS data. In an aspect, as discussed supra, all eNBs in the same MBSFN area may coordinate with one another, and assign the same ACK/NACK resources that may be shared among the eNBs in the same MBSFN area. In another aspect, as discussed supra, each eNB may assign a specific ACK/NACK resource per eNB.

FIG. 13 is a flowchart 1300 of a method of wireless communication, expanding from the flowchart 1200 of FIG. 12, according to an aspect of the disclosure. The method may be performed by a UE (e.g., the

UE

804, 834, 864, the apparatus 1402/1402') . The flowchart 1300 expands from FIG. 12 at 1212. At 1302, the UE determines whether the MBMS data is decoded based on the received at least one data packet and the at least one repair packet. At 1304, the UE transmits, when the MBMS data is unsuccessfully decoded, a subsequent session NACK response to indicate that the MBMS data is unsuccessfully decoded. At 1306, the UE receives at least one additional repair packet for decoding the MBMS data in response to transmitting the subsequent session NACK response. For example, as discussed supra, when the eNB receives the session NACK response, the eNB sends at least one repair packet to the UE, such that the UE may attempt to decode the MBMS data using the repair packet and the data packet (s) received during the MBMS session. For example, as discussed supra, if the UE still cannot successfully decode the MBMS data using the repair packet and the data packet (s) , the UE sends another session NACK response, such that the eNB sends one or more additional repair packets to the UE.

FIG. 14 is a conceptual data flow diagram 1400 illustrating the data flow between different modules/means/components in an exemplary apparatus 1402. The apparatus may be a UE. The apparatus includes a reception module 1404, a transmission module 1406, a decoding management module 1408, a feedback management module 1410, and a connection mode management module 1412.

The reception module 1404 receives via 1472 at least one data packet of an MBMS session, and forwards the at least one data packet of the MBMS session to the decoding management module 1408 via 1474. The decoding management module 1408 determines whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet. In an aspect, the decoding management module 1408 may determine whether the MBMS data is successfully decoded by determining whether a sufficient number of packets for decoding the MBMS data are received. When the MBMS data is unsuccessfully decoded, the feedback management module 1410 transmits, via 1478 and 1480 using the transmission module 1406, a session NACK response to indicate that the MBMS data is unsuccessfully decoded (e.g., based on the determination received from the decoding management module 1408 via 1476) . In an aspect, the session NACK response may be an HARQ feedback response. In an aspect, the session NACK response may be transmitted via a physical layer. The connection mode management module 1412 may cause the UE 1402 to enter into an RRC connected mode to receive the at least one repair packet when the MBMS data is unsuccessfully decoded and the UE is in an RRC idle mode (e.g., based on the determination received from the decoding management module 1408 via 1482) . The connection mode management module 1412 may configure the transmission module 1406 via 1484 and the reception module 1404 via 1486 according to the RRC connected mode if the UE 1402 enters into the RRC connected mode. The decoding management module 1408 receives, via 1472 and 1474 using the reception module 1404, at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response.

The feedback management module 1410 may refrain from transmitting, when the MBMS data is successfully decoded, a session ACK response to indicate that the MBMS data is successfully decoded (e.g., based on the determination received from the decoding management module 1408 via 1476) .

In an aspect, the session NACK response is sent via a resource shared among a plurality of UEs to transmit session NACK responses. In such an aspect, the resource is indicated in at least one of an MCCH or MSI. In such an aspect, the resource comprises a plurality of resources, and each of the plurality of resources is assigned for a respective amount of repair packets for decoding the MBMS data. In such an aspect, the resource is shared among a plurality of base stations or is assigned to a specific base station. In an aspect, if the decoding management module 1408 determines that less than the sufficient number of packets for decoding the MBMS data are received, the decoding management module 1408 may determine a number of additional packets (e.g., repair packets) needed to successfully decode the MBMS data, and may send the session NACK response using a resource of the plurality of resources that corresponds to the number of the repair packets needed for decoding the MBMS data.

The decoding management module 1408 determines whether the MBMS data is decoded based on the received at least one data packet and the at least one repair packet. The feedback management module 1410 transmits, when the MBMS data is unsuccessfully decoded, via 1478 and 1480 using the transmission module 1406, a subsequent session NACK response to indicate that the MBMS data is unsuccessfully decoded. The decoding management module 1408 receives, via 1472 and 1474 using the reception module 1404, at least one additional repair packet for decoding the MBMS data in response to transmitting the subsequent session NACK response.

The apparatus may include additional modules that perform each of the blocks of the algorithm in the aforementioned flowcharts of FIGs. 12 and 13. As such, each block in the aforementioned flowcharts of FIGs. 12 and 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. 15 is a diagram 1500 illustrating an example of a hardware implementation for an apparatus 1402' employing a processing system 1514. The processing system 1514 may be implemented with a bus architecture, represented generally by the bus 1524. The bus 1524 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1514 and the overall design constraints. The bus 1524 links together various circuits including one or more processors and/or hardware modules, represented by the processor 1504, the

modules

1404, 1406, 1408, 1410, 1412, and the computer-readable medium /memory 1506. The bus 1524 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 1514 may be coupled to a transceiver 1510. The transceiver 1510 is coupled to one or more antennas 1520. The transceiver 1510 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 1510 receives a signal from the one or more antennas 1520, extracts information from the received signal, and provides the extracted information to the processing system 1514, specifically the reception module 1404. In addition, the transceiver 1510 receives information from the processing system 1514, specifically the transmission module 1406, and based on the received information, generates a signal to be applied to the one or more antennas 1520. The processing system 1514 includes a processor 1504 coupled to a computer-readable medium /memory 1506. The processor 1504 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 1506. The software, when executed by the processor 1504, causes the processing system 1514 to perform the various functions described supra for any particular apparatus. The computer-readable medium /memory 1506 may also be used for storing data that is manipulated by the processor 1504 when executing software. The processing system further includes at least one of the

modules

1404, 1406, 1408, 1410, and 1412. The modules may be software modules running in the processor 1504, resident/stored in the computer readable medium / memory 1506, one or more hardware modules coupled to the processor 1504, or some combination thereof. The processing system 1514 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 one configuration, the apparatus 1402/1402' for wireless communication includes means for receiving at least one data packet of an MBMS session； means for determining whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet； means for transmitting, when the MBMS data is unsuccessfully decoded； a session NACK response to indicate that the MBMS data is unsuccessfully decoded； and means for receiving at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response. The apparatus 1402/1402' may further include means for determining whether the MBMS data is decoded based on the received at least one data packet and the at least one repair packet； means for transmitting, when the MBMS data is unsuccessfully decoded, a subsequent session NACK response to indicate that the MBMS data is unsuccessfully decoded； and means for receiving at least one additional repair packets for decoding the MBMS data in response to transmitting the subsequent session NACK response. The apparatus 1402/1402' may further include means for entering into an RRC connected mode to receive the at least one repair packet when the MBMS data is unsuccessfully decoded and the UE is in an RRC idle mode. The apparatus 1402/1402' may further include means for refraining from transmitting, when the MBMS data is successfully decoded, a session ACK response to indicate that the MBMS data is successfully decoded.

The aforementioned means may be one or more of the aforementioned modules of the apparatus 1402 and/or the processing system 1514 of the apparatus 1402' configured to perform the functions recited by the aforementioned means. As described supra, the processing system 1514 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.

FIG. 16 is a flowchart 1600 of a method of wireless communication, according to an aspect of the disclosure. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1602, the eNB transmits MBMS data of an MBMS session to a UE. In an aspect, the eNB transmits MBMS data of the MBMS session to any UE (s) in the coverage area of the eNB. . At 1604, the eNB receives a session NACK response from the UE, where the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE. In an aspect, the session NACK response is an HARQ feedback response. At 1606, the eNB may perform additional features, as discussed infra. At 1608, the eNB transmits at least one repair packet to the UE based on the session NACK response. At 1610, the eNB may perform additional features, as discussed infra.

For example, as discussed supra, if the UE has not successfully decoded the MBMS data of the MBMS session, the UE sends a session NACK response to the eNB at the end of the MBMS session, and thus the session NACK response may indicate to the eNB that the MBMS data of the MBMS session is not successfully decoded. For example, as discussed supra, when the eNB receives the session NACK response, the eNB sends repair packets to the UE, such that the UE may attempt to decode the MBMS data using the repair packets. For example, as discussed supra, the UE may utilize an HARQ feedback feature to send a session ACK/NACK response.

According to a first option of the disclosure, the eNB transmits the at least one repair packet to the UE by transmitting the at least one repair packet to the UE via unicast transmission. For example, as discussed supra, according to a first option, the eNB transmits repair packets to the UE via unicast transmission when the eNB receives a session NACK response.

According to a second option of the disclosure, the eNB transmits the at least one repair packet to the UE by transmitting the at least one repair packet via broadcast transmission using at least one of a small MBSFN or a group bearer, where the small MBSFN covers a smaller area than an original MBSFN that is used to transmit the MBMS data. For example, as discussed supra, according to a second option, the eNB transmits the repair packets via broadcast transmission using a small MBSFN or via a group bearer. For example, as discussed supra, the small MBSFN covers a smaller area than an original MBSFN that is initially used to transmit the MBMS data of the MBMS session.

According to a third option of the disclosure, the eNB transmits the at least one repair packet to the UE by transmitting the at least one repair packet via broadcast transmission using an original MBSFN, where the original MBSFN is used to transmit the MBMS data. Further, in the third option, the eNB transmits the at least one repair packet by coordinating with other base stations in the original MBSFN for the transmission of the at least one repair packet, where the at least one repair packet is transmitted based on the coordination with the other base stations in the original MBSFN. The eNB coordinates with the other base stations in the original MBSFN by signaling information about the transmission of the at least one repair packet to the other base stations, where the coordination with the other base stations is based on the signaled information. In an aspect, the information about the transmission of the at least one repair packet is signaled to each of the other base stations via an X2 interface. In an aspect, the information about the transmission of the at least one repair packet is signaled to each of the other base stations via a MCE.

For example, as discussed supra, according to the third option, the eNB transmits the repair packets via broadcast transmission using the original MBSFN that is initially used to transmit the MBMS data of the MBMS session. For example, as discussed supra, all eNBs in the original MBSFN are coordinated for transmission of the repair packets. For example, as discussed supra, if an eNB receives a NACK response (e.g., a session NACK response) from a UE and determines to transmit repair packets to the UE, the eNB signals other eNBs in the same MBSFN (e.g., the original MBSFN) to coordinate transmission of the repair packets. For example, as discussed supra, in one aspect, the eNB may signal the other eNBs in the same MBSFN via an X2 interface to coordinate the transmission. For example, as discussed supra, in another aspect, eNBs in the same MBSFN may send a NACK status (according to a session NACK response) to an MCE, and the eNBs may receive, from the MCE, information on how to transmit the repair packets to the UE.

FIGs. 17A-17C are flowcharts of method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. FIG. 17A is a flowchart 1700 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1700 expands from FIG. 16 at 1606. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1702, the eNB receives, from a BM-SC, the at least one repair packet to be transmitted to the UE. For example, as discussed supra, the repair packets may be transferred from a BM-SC to the eNB or may be generated at the eNB.

FIG. 17B is a flowchart 1730 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1730 expands from FIG. 16 at 1606. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1732, the eNB receives one or more FEC parameters from a BM-SC. At 1734, the eNB generates, based on the one or more FEC parameters, the at least one repair packet to be transmitted to the UE. For example, as discussed supra, the BM-SC may send application layer FEC parameters to the eNB, and the eNB may generate the repair packets based on the FEC parameters.

FIG. 17C is a flowchart 1760 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1760 expands from FIG. 16 at 1606. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1762, the eNB generates response periodicity information based on at least one of the received session NACK response from the UE or another session NACK response received from another UE. At 1764, the eNB sends the response periodicity information to the UE, where the response periodicity information is used to configure at the UE a periodicity for transmission of a subsequent session NACK response.

For example, as discussed supra, the eNB may configure the UE to send a session ACK/NACK response with a response periodicity that is based on statistics of session ACK/NACK reception. For example, as discussed supra, the eNB may send a response periodicity to the UE such that the UE may send a session ACK/NACK response based on the response periodicity. For example, as discussed supra, in a case with all or many of the UEs need a lot of repair packets, the eNB may configure the response periodicity to a long periodicity such that the UEs may not send a session NACK for a predetermined period time even when the UEs cannot decode. For example, as discussed supra, if all or many of the UEs need fewer repair packets (e.g., less than 50％ of the number of packets sufficient for decoding) , then the eNB may configure the response periodicity to a short periodicity.

FIGs. 18A-18C are flowcharts of method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. FIG. 18A is a flowchart 1800 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1800 expands from FIG. 16 at 1610. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1802, the eNB receives a subsequent session NACK response from the UE in response to the at least one repair packet being transmitted to the UE, where the subsequent session NACK response indicates that the MBMS data is unsuccessfully decoded. At 1804, the eNB retransmits the at least one repair packet to the UE based on the subsequent session NACK response. In an aspect, a number of the at least one repair packet to be transmitted to the UE is determined based on the received session NACK response. In an aspect, the at least one repair packet is transmitted to the UE in increments of the number of the at least one repair packet.

For example, as discussed supra, the UE may continue to send a session NACK response as long as the UE cannot decode the MBMS data after the MBMS session ends. For example, as discussed supra, after the MBMS session ends, the eNB may determine a number of repair packets to be sent to the UE if the session NACK response is received at the end of the MBMS session. For example, as discussed supra, instead of transmitting the entire repair packets at once, the eNB may transmit the repair packets in smaller increments over several transmissions to the UE.

FIG. 18B is a flowchart 1830 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1830 expands from FIG. 16 at 1610. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1832, the eNB receives a packet NACK response from the UE in response to the at least one repair packet being transmitted to the UE, where the packet NACK response indicates that the at least one repair packet is unsuccessfully decoded at the UE. At 1834, the eNB retransmits the at least one repair packet to the UE based on the packet NACK response. In an aspect, the base station enables the packet NACK response based on statistics of session NACK response reception among a plurality of UEs.

For example, as discussed supra, when the eNB receives the packet NACK response indicating a particular packet, the eNB may retransmit a repair packet corresponding to the particular packet. For example, as discussed supra, the eNB may enable a packet ACK/NACK response based on statistics of session ACK/NACK reception.

FIG. 18C is a flowchart 1860 of a method of wireless communication, expanding from the flowchart 1600 of FIG. 16, according to an aspect of the disclosure. The flowchart 1860 expands from FIG. 16 at 1610. The method may be performed by an eNB (e.g., the

eNB

814, 844, 874, the apparatus 1902/1902') . At 1862, the eNB retransmits the repair packets at least once without receiving a session NACK response. For example, as discussed supra, the eNB may send several retransmissions back-to-back without waiting for HARQ feedback from the UE.

FIG. 19 is a conceptual data flow diagram 1900 illustrating the data flow between different modules/means/components in an exemplary apparatus 1902. The apparatus may be an eNB. The apparatus includes a reception module 1904, a transmission module 1906, a data management module 1908, a repair packet management module 1910, and a feedback management module 1912.

The data management module 1908 transmits, via 1972 and 1974 using the transmission module 1906, MBMS data of an MBMS session to a UE 1950. The feedback management module 1912 receives, via 1976 and 1978 using the reception module 1904, a session NACK response from the UE 1950, where the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE 1950. In an aspect, the session NACK response is an HARQ feedback response. The repair packet management module 1910 transmits, via 1982 and 1974 using the transmission module 1906, at least one repair packet to the UE 1950 based on the session NACK response (e.g., where the session NACK response is communicated to the repair packet management module 1910 via 1980) . The repair packet management module 1910 may receive information on the MBMS data from the data management module 1908 via 1988 and use the information to generate the at least one repair packet.

In an aspect, the repair packet management module 1910 receives, via 1984 and 1990 using the reception module 1904, from a BM-SC 1960, the at least one repair packet to be transmitted to the UE 1950. In another aspect, the repair packet management module 1910 receives, via 1984 and 1990 using the reception module 1904, one or more FEC parameters from the BM-SC 1960, and generates, based on the one or more FEC parameters, the at least one repair packet to be transmitted to the UE 1950. The UE 1950 may also communicate to the BM-SC 1960 via 1992 using the transmission module 1906.

The feedback management module 1912 generates response periodicity information based on at least one of the received session NACK response from the UE 1950 or another session NACK response received from another UE. The feedback management module 1912 sends, via 1986 and 1974 using the transmission module 1906, the response periodicity information to the UE 1950, where the response periodicity information is used to configure at the UE 1950 a periodicity for transmission of a subsequent session NACK response.

According to a first option of the disclosure, the repair packet management module 1910 transmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet to the UE by transmitting the at least one repair packet to the UE via unicast transmission.

According to a second option of the disclosure, the repair packet management module 1910 transmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet to the UE by transmitting the at least one repair packet via broadcast transmission using at least one of a small MBSFN or a group bearer, where the small MBSFN covers a smaller area than an original MBSFN that is used to transmit the MBMS data.

The feedback management module 1912 receives, via 1976 and 1978 using the reception module 1904, a subsequent session NACK response from the UE 1950 in response to the at least one repair packet being transmitted to the UE 1950, where the subsequent session NACK response indicates that the MBMS data is unsuccessfully decoded. The repair packet management module 1910 retransmits, via 1986 and 1974 using the transmission module 1906, the at least one repair packet to the UE 1950 based on the subsequent session NACK response. In an aspect, a number of the at least one repair packet to be transmitted to the UE 1950 is determined based on the received session NACK response. In an aspect, the at least one repair packet is transmitted to the UE 1950 in increments of the number of the at least one repair packet.

The feedback management module 1912 receives, via 1976 and 1978 using the reception module 1904, a packet NACK response from the UE 1950 in response to the at least one repair packet being transmitted to the UE 1950, where the packet NACK response indicates that the at least one repair packet is unsuccessfully decoded at the UE 1950. The repair packet management module 1910 retransmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet to the UE 1950 based on the packet NACK response (e.g., where the packet NACK response is communicated to the repair packet management module 1910 via 1980) . In an aspect, the eNB enables the packet NACK response based on statistics of session NACK response reception among a plurality of UEs.

In an aspect, the repair packet management module 1910 retransmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet at least once without receiving a session NACK response.

According to a third option of the disclosure, the repair packet management module 1910 transmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet to the UE by transmitting the at least one repair packet via broadcast transmission using the original MBSFN, where the original MBSFN is used to transmit the MBMS data. Further, in the third option, the repair packet management module 1910 transmits, via 1982 and 1974 using the transmission module 1906, the at least one repair packet by coordinating with other base stations in the original MBSFN for the transmission of the at least one repair packet, where the at least one repair packet is transmitted based on the coordination with the other base stations in the original MBSFN. The repair packet management module 1910 coordinates with the other base stations in the original MBSFN by signaling information about the transmission of the at least one repair packet to the other base stations, where the coordination with the other base stations is based on the signaled information. In an aspect, the information about the transmission of the at least one repair packet is signaled to each of the other base stations via an X2 interface. In an aspect, the information about the transmission of the at least one repair packet is signaled to each of the other base stations via a MCE.

The apparatus may include additional modules that perform each of the blocks of the algorithm in the aforementioned flowcharts of FIGs. 16-18. As such, each block in the aforementioned flowcharts of FIGs. 16-18 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. 20 is a diagram 2000 illustrating an example of a hardware implementation for an apparatus 1902' employing a processing system 2014. The processing system 2014 may be implemented with a bus architecture, represented generally by the bus 2024. The bus 2024 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 2014 and the overall design constraints. The bus 2024 links together various circuits including one or more processors and/or hardware modules, represented by the processor 2004, the

modules

1904, 1906, 1908, 1910, 1912, and the computer-readable medium /memory 2006. The bus 2024 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 2014 may be coupled to a transceiver 2010. The transceiver 2010 is coupled to one or more antennas 2020. The transceiver 2010 provides a means for communicating with various other apparatus over a transmission medium. The transceiver 2010 receives a signal from the one or more antennas 2020, extracts information from the received signal, and provides the extracted information to the processing system 2014, specifically the reception module 1904. In addition, the transceiver 2010 receives information from the processing system 2014, specifically the transmission module 1906, and based on the received information, generates a signal to be applied to the one or more antennas 2020. The processing system 2014 includes a processor 2004 coupled to a computer-readable medium /memory 2006. The processor 2004 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 2006. The software, when executed by the processor 2004, causes the processing system 2014 to perform the various functions described supra for any particular apparatus. The computer-readable medium /memory 2006 may also be used for storing data that is manipulated by the processor 2004 when executing software. The processing system further includes at least one of the

modules

1904, 1906, 1908, 1910, and 1912. The modules may be software modules running in the processor 2004, resident/stored in the computer readable medium / memory 2006, one or more hardware modules coupled to the processor 2004, or some combination thereof. The processing system 2014 may be a component of the eNB 610 and may include the memory 676 and/or at least one of the TX processor 616, the RX processor 670, and the controller/processor 675.

In one configuration, the apparatus 1902/1902' for wireless communication includes means for transmitting MBMS data of an MBMS session to a UE； means for receiving a session NACK response from the UE, where the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE； and means for transmitting at least one repair packet to the UE based on the session NACK response.

In an aspect, the means for transmitting the at least one repair packet to the UE is configured to transmit the at least one repair packet to the UE via unicast transmission. In an aspect, the means for transmitting the at least one repair packet to the UE is configured to transmit the at least one repair packet via broadcast transmission using at least one of a small MBSFN or a group bearer, wherein the small MBSFN covers a smaller area than an original MBSFN that is used to transmit the MBMS data. The apparatus 1902/1902' may further include means for receiving, from a BM-SC, the at least one repair packet to be transmitted to the UE. The apparatus 1902/1902' may further include means for receiving one or more FEC parameters from a BM-SC； and means for generating, based on the one or more FEC parameters, the at least one repair packet to be transmitted to the UE. The apparatus 1902/1902' may further include means for receiving a subsequent session NACK response from the UE in response to the at least one repair packet being transmitted to the UE, where the subsequent session NACK response indicates that the MBMS data is unsuccessfully decoded； and means for retransmitting the at least one repair packet to the UE based on the subsequent session NACK response. The apparatus 1902/1902' may further include means for generating response periodicity information based on at least one of the received session NACK response from the UE or another session NACK response received from another UE； and means for sending the response periodicity information to the UE, where the response periodicity information is used to configure at the UE a periodicity for transmission of a subsequent session NACK response. The apparatus 1902/1902' may further include means for receiving a packet NACK response from the UE in response to the at least one repair packet being transmitted to the UE, where the packet NACK response indicates that the at least one repair packet is unsuccessfully decoded at the UE； and means for retransmitting the at least one repair packet to the UE based on the packet NACK response. The apparatus 1902/1902' may further include means for retransmitting the at least one repair packet at least once without receiving a session NACK response.

In an aspect, the means for transmitting the at least one repair packet to the UE is configured to transmit the at least one repair packet via broadcast transmission using an original MBSFN, wherein the original MBSFN is used to transmit the MBMS data. In such an aspect, the means for transmitting the at least one repair packet to the UE is further configured to coordinate with other base stations in the original MBSFN for the transmission of the at least one repair packet, wherein the at least one repair packet is transmitted based on the coordination with the other base stations in the original MBSFN.

The aforementioned means may be one or more of the aforementioned modules of the apparatus 1902 and/or the processing system 2014 of the apparatus 1902' configured to perform the functions recited by the aforementioned means. As described supra, the processing system 2014 may include the TX Processor 616, the RX Processor 670, and the controller/processor 675. As such, in one configuration, the aforementioned means may be the TX Processor 616, the RX Processor 670, and the controller/processor 675 configured to perform the functions recited by the aforementioned means.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks 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. ”

Claims

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

receiving at least one data packet of a multimedia broadcast multicast service (MBMS) session；

determining whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet；

transmitting, when the MBMS data is unsuccessfully decoded, a session negative acknowledgement (NACK) response to indicate that the MBMS data is unsuccessfully decoded； and

receiving at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response.
The method of claim 1, wherein the determining whether the MBMS data is successfully decoded comprises:

determining whether a sufficient number of packets for decoding the MBMS data are received.
The method of claim 1, further comprising:

determining whether the MBMS data is decoded based on the received at least one data packet and the at least one repair packet；

transmitting, when the MBMS data is unsuccessfully decoded, a subsequent session NACK response to indicate that the MBMS data is unsuccessfully decoded； and

receiving at least one additional repair packet for decoding the MBMS data in response to transmitting the subsequent session NACK response.
The method of claim 1, further comprising:

entering into a radio resource control (RRC) connected mode to receive the at least one repair packet when the MBMS data is unsuccessfully decoded and the UE is in an RRC idle mode.
The method of claim 1, further comprising:

refraining from transmitting, when the MBMS data is successfully decoded, a session acknowledgment (ACK) response to indicate that the MBMS data is successfully decoded.
The method of claim 1, wherein the session NACK response is transmitted via a physical layer.
The method of claim 1, wherein the session NACK response is sent via a resource shared among a plurality of UEs to transmit session NACK responses.
A method for wireless communication by a base station, comprising:

transmitting multimedia broadcast multicast service (MBMS) data of an MBMS session to a user equipment (UE) ；

receiving a session negative acknowledgement (NACK) response from the UE, wherein the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE； and

transmitting at least one repair packet to the UE based on the session NACK response.
The method of claim 8, further comprising:

receiving, from a broadcast multicast service center (BM-SC) , the at least one repair packet to be transmitted to the UE.
The method of claim 8, further comprising:

receiving one or more error correction (FEC) parameters from a broadcast multicast service center (BM-SC) ； and

generating, based on the one or more FEC parameters, the at least one repair packet to be transmitted to the UE.
The method of claim 8, wherein the transmitting the at least one repair packet to the UE comprises:

transmitting the at least one repair packet to the UE via unicast transmission.
The method of claim 8, wherein the transmitting the at least one repair packet to the UE comprises:

transmitting the at least one repair packet via broadcast transmission using at least one of a small multicast broadcast single frequency network (MBSFN) or a group bearer, wherein the small MBSFN covers a smaller area than an original MBSFN that is used to transmit the MBMS data.
The method of claim 8, further comprising:

receiving a subsequent session NACK response from the UE in response to the at least one repair packet being transmitted to the UE, wherein the subsequent session NACK response indicates that the MBMS data is unsuccessfully decoded； and

retransmitting the at least one repair packet to the UE based on the subsequent session NACK response.
The method of claim 8, further comprising:

generating response periodicity information based on at least one of the received session NACK response from the UE or another session NACK response received from another UE； and

sending the response periodicity information to the UE, wherein the response periodicity information is used to configure at the UE a periodicity for transmission of a subsequent session NACK response.
The method of claim 8, further comprising:

receiving a packet NACK response from the UE in response to the at least one repair packet being transmitted to the UE, wherein the packet NACK response indicates that the at least one repair packet is unsuccessfully decoded at the UE； and

retransmitting the at least one repair packet to the UE based on the packet NACK response.
The method of claim 15, wherein the base station enables the packet NACK response based on statistics of session NACK response reception among a plurality of UEs.
The method of claim 8, further comprising:

retransmitting the at least one repair packet at least once without receiving a session NACK response.
The method of claim 8, wherein the transmitting the at least one repair packet to the UE comprises:

transmitting the at least one repair packet via broadcast transmission using an original multicast broadcast single frequency network (MBSFN) , wherein the original MBSFN is used to transmit the MBMS data.
The method of claim 18, wherein the transmitting the at least one repair packet to the UE further comprises:

coordinating with other base stations in the original MBSFN for the transmission of the at least one repair packet, wherein the at least one repair packet is transmitted based on the coordination with the other base stations in the original MBSFN.
The method of claim 19, wherein the coordinating with the other base stations in the original MBSFN comprises:

signaling information about the transmission of the at least one repair packet to the other base stations, wherein the coordination with the other base stations is based on the signaled information.
A user equipment (UE) for wireless communication, comprising:

means for receiving at least one data packet of a multimedia broadcast multicast service (MBMS) session；

means for determining whether MBMS data of the MBMS session is successfully decoded based on the received at least one data packet；

means for transmitting, when the MBMS data is unsuccessfully decoded, a session negative acknowledgement (NACK) response to indicate that the MBMS data is unsuccessfully decoded； and

means for receiving at least one repair packet for decoding the MBMS data in response to transmitting the session NACK response.
The UE of claim 21, further comprising:

means for determining whether the MBMS data is decoded based on the received at least one data packet and the at least one repair packet；

means for transmitting, when the MBMS data is unsuccessfully decoded, a subsequent session NACK response to indicate that the MBMS data is unsuccessfully decoded； and

means for receiving at least one additional repair packet for decoding the MBMS data in response to transmitting the subsequent session NACK response.
The UE of claim 21, further comprising:

means for entering into a radio resource control (RRC) connected mode to receive the at least one repair packet when the MBMS data is unsuccessfully decoded and the UE is in an RRC idle mode.
A base station for wireless communication, comprising:

means for transmitting multimedia broadcast multicast service (MBMS) data of an MBMS session to a user equipment (UE) ；

means for receiving a session negative acknowledgement (NACK) response from the UE, wherein the session NACK response indicates that the MBMS data is unsuccessfully decoded at the UE； and

means for transmitting at least one repair packet to the UE based on the session NACK response.
The base station of claim 24, wherein the means for transmitting the at least one repair packet to the UE is configured to:

transmit the at least one repair packet to the UE via unicast transmission.
The base station of claim 24, wherein the means for transmitting the at least one repair packet to the UE is configured to:

transmit the at least one repair packet via broadcast transmission using at least one of a small multicast broadcast single frequency network (MBSFN) or a group bearer, wherein the small MBSFN covers a smaller area than an original MBSFN that is used to transmit the MBMS data.
The base station of claim 24, further comprising:

means for receiving a subsequent session NACK response from the UE in response to the at least one repair packet being transmitted to the UE, wherein the subsequent session NACK response indicates that the MBMS data is unsuccessfully decoded； and

means for retransmitting the at least one repair packet to the UE based on the subsequent session NACK response.
The base station of claim 24, further comprising:

means for receiving a packet NACK response from the UE in response to the at least one repair packet being transmitted to the UE, wherein the packet NACK response indicates that the at least one repair packet is unsuccessfully decoded at the UE； and

means for retransmitting the at least one repair packet to the UE based on the packet NACK response.
The base station of claim 24, wherein the means for transmitting the at least one repair packet to the UE is configured to:

transmit the at least one repair packet via broadcast transmission using an original multicast broadcast single frequency network (MBSFN) , wherein the original MBSFN is used to transmit the MBMS data.
The base station of claim 29, wherein the means for transmitting the at least one repair packet to the UE is further configured to:

coordinate with other base stations in the original MBSFN for the transmission of the at least one repair packet, wherein the at least one repair packet is transmitted based on the coordination with the other base stations in the original MBSFN.