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Title:
DEVICES AND METHOD OF EVOLVED MULTIMEDIA BROADCAST MULTICAST SERVICE HANDOVER
Document Type and Number:
WIPO Patent Application WO/2017/095434
Kind Code:
A1
Abstract:
Devices and methods of limiting eMBMS service disruptions during handover are generally described. The UE may transmit to a serving eNB TMGIs of ongoing and interested eMBMS services for the UE. The UE may receive a RRCConnectionReconfiguration message that includes a MBSFN subframe configuration list of a target eNB for at least the eMBMS services identified by the TMGIs and establish the eMBMS services at the target eNB based thereon. The RRCConnectionReconfiguration message may include all eMBMS allocations in all MBSFN areas and a subframe configuration list for all eMBMS services in all areas, as well as eNB and target eNB MSI information and MSI validity timing. If the target eNB MSI will be invalid when handover of the UE is completed, the UE may request from the target eNB the target eNB MSI on dedicated signaling.

Inventors:
PANCHAL AJAY (US)
VERMA SIDDHARTH (US)
ZHANG YUJIAN (CN)
Application Number:
PCT/US2015/063914
Publication Date:
June 08, 2017
Filing Date:
December 04, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
INTEL IP CORP (US)
International Classes:
H04W36/00; H04W4/06; H04W36/02; H04W36/08; H04W88/02
Foreign References:
US20110305184A12011-12-15
US20140169255A12014-06-19
US20140126454A12014-05-08
US20140153471A12014-06-05
Other References:
N. D. NGUYEN ET AL.: "Service continuity for eMBMS in LTE/LTE-Advanced network: Standard analysis and supplement", CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC, 10 January 2014 (2014-01-10), pages 219 - 224, XP032626126, Retrieved from the Internet
Attorney, Agent or Firm:
PERDOK, Monique M. et al. (P.A.c/o CPA Global,P.O. Box 5205, Minneapolis Minnesota, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. An apparatus of user equipment (UE) comprising:

a transceiver arranged to communicate with an evolved NodeB (eNB); and

processing circuitry arranged to:

configure the transceiver to receive from the eNB Evolved Multimedia Broadcast Multicast Services (eMBMS) traffic data of an eMBMS service;

configure the transceiver to receive from the eNB eMBMS information of a target eNB in an RRCConnectionReconfiguration message used during handover of the UE from the eNB to the target eNB, the eMBMS information comprising eMBMS subframe allocation of the target eNB; and

based on the eMBMS subframe allocation, configure the transceiver to establish the eMBMS service at the target eNB free from an eMBMS interruption when the eMBMS subframe allocation at the target eNB is different from an eMBMS subframe allocation at the eNB.

2. The apparatus of claim 1, wherein:

the eMBMS information comprises at least one of System Information Block 2 (SIB2)-related eMBMS information and Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe allocations.

3. The apparatus of claim 1 or 2, wherein:

the RRCConnectionReconfiguration message comprises a complete set of eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB.

4. The apparatus of claim 3, wherein:

the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each MBSFN area.

5. The apparatus of claim 4, wherein:

the RRCConnectionReconfiguration message further comprises eMBMS System Information Block 2 (SIB2)-related information comprising a MBSFN sub frame configuration list, eMBMS SIB 13 -related information comprising a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration-related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)-InfoList.

6. The apparatus of claim 1 or 2, wherein:

the handover message comprises an RRCConnectionReconfiguration message, the RRCConnectionReconfiguration message further comprising eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB, the eMBMS allocations limited to eMBMS allocations associated with eMBMS services received by the UE from the eNB. 7. The apparatus of claim 6, wherein the processing circuitry is further arranged to:

configure the transceiver to provide to the eNB, prior to receiving the eMBMS information, a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE.

8. The apparatus of claim 7, wherein the processing circuitry is further arranged to:

configure the transceiver to provide the TMGI list in a measurement report to the eNB, the measurement report comprising a measurement of reference signals transmitted by the eNB.

9. The apparatus of claim 1 or 2, wherein the processing circuitry is further arranged to: configure the transceiver to receive a request from the eNB for a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE,

in response to receiving the request from the eNB for the TMGI list, configure the transceiver to transmit to the eNB the TMGI list, and

in response to transmitting the TMGI list to the eNB, configure the transceiver to receive the RRCConnectionReconfiguration message, the RRCConnectionReconfiguration message further comprising eMBMS service allocations associated with the TMGIs in the list and free from eMBMS service allocations not associated with TMGIs in the list.

10. The apparatus of claim 9, wherein:

the RRCConnectionReconfiguration message further comprises eMBMS System Information Block 2 (SIB2)-related information comprising a

Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe configuration list and multicast traffic channel (MTCH) information of MTCHs associated with the TMGIs in the TMGI list, the MTCH information comprising a number of MTCHs and MTCH allocation information for each MTCH.

1 1. The apparatus of claim 1 or 2, wherein:

the RRCConnectionReconfiguration message further comprises the eMBMS information of the target eNB and free from eMBMS System

Information Block 13 (SIB 13)-related information and comprising eMBMS SIB2-related information comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe configuration list.

12. The apparatus of claim 1 or 2, wherein the

RRCConnectionReconfiguration message further comprises:

multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid.

13. The apparatus of claim 12, wherein the processing circuitry is further arranged to:

determine from the validity timing of the MSI of the target eNB that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, and

in response to determining that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, configure the transceiver to request on dedicated signaling to the UE the MSI of the target eNB from the target eNB.

14. The apparatus of claim 1 or 2, wherein the processing circuitry is further arranged to:

establish, based on the eMBMS information, eMBMS service at the target eNB during handover free from an eMBMS interruption when an eMBMS subframe allocation at the target eNB is different from a subframe allocation at the eNB.

15. The apparatus of claim 1 or 2, further comprising:

an antenna configured to provide communications between the transceiver and the eNB. 16. An apparatus of an evolved NodeB (eNB) comprising:

a transceiver configured to communicate with a user equipment (UE); and

processing circuitry configured to:

configure the transceiver to transmit to the UE Evolved

Multimedia Broadcast Multicast Services (eMBMS) traffic data of an eMBMS service;

determine that handover of the UE to a target eNB is appropriate; and configure the transceiver to transmit to the UE eMBMS information of the target eNB in a RRCConnectionReconfiguration message initiating handover of the UE from the eNB to the target eNB, the eMBMS information comprising eMBMS System Information Block 2 (SIB2)-related information of the target eNB.

17. The apparatus of claim 16, wherein:

the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area.

18. The apparatus of claim 17, wherein:

the eMBMS System Information Block 2 (SIB2)-related information comprises a MBSFN subframe configuration list, and

the RRCConnectionReconfiguration message further comprises eMBMS

SIB 13 -related information comprising a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration- related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)- InfoList.

19. The apparatus of claim 16 or 17, wherein:

the RRCConnectionReconfiguration message further comprises eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB, the eMBMS allocations limited to eMBMS allocations associated with eMBMS services transmitted by the eNB to the UE. 20. The apparatus of claim 19, wherein the processing circuitry is further arranged to: configure the transceiver to receive from the UE, prior to transmitting the eMBMS information, a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE, configure the transceiver to transmit reference signals, and

configure the transceiver to receive the TMGI list in a measurement report comprising a measurement of the reference signals.

21. The apparatus of claim 16 or 17, wherein the processing circuitry is further arranged to:

configure the transceiver to transmit to the UE a request from the eNB for a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE,

in response to transmitting the request from the eNB for the TMGI list, configure the transceiver to receive to the eNB the TMGI list, and

in response to receiving the TMGI list to the eNB, configure the transceiver to transmit the RRCConnectionReconfiguration message, the RRCConnectionReconfiguration message further comprising eMBMS service allocations associated with the TMGIs in the list and free from eMBMS service allocations not associated with TMGIs in the list, the eMBMS SIB2-related information comprising a Multimedia Broadcast Multicast Service Single

Frequency Network (MBSFN) subfirame configuration list and multicast traffic channel (MTCH) information of MTCHs associated with the TMGIs in the TMGI list, the MTCH information comprising a number of MTCHs and MTCH allocation information for each MTCH.

22. The apparatus of claim 16 or 17, wherein:

the RRCConnectionReconfiguration message further comprises:

multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and

MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid.

23. A computer-readable storage medium that stores instructions for execution by one or more processors of user equipment (UE) to communicate with an evolved NodeB (eNB), the one or more processors to configure the UE to:

transmit to the eNB a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested Evolved Multimedia Broadcast Multicast Services (eMBMS) service for the UE;

receive from the eNB a RRCConnectionReconfiguration message used to initiate handover of the UE from the eNB to a target eNB, the

RRCConnectionReconfiguration message comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) sub frame configuration list of the target eNB for at least the eMBMS services identified by the TMGIs; and

establish the eMBMS services identified by the TMGIs at the target eNB based on the MBSFN subframe configuration list.

24. The medium of claim 23, wherein:

the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each MBSFN area, a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration- related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)-InfoList.

25. The medium of claim 23 or 24, wherein the

RRCConnectionReconfiguration message further comprises:

multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and

MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid, and the instructions further configure the UE to:

determine from the validity timing of the MSI of the target eNB that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, and

in response to determining that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, request on dedicated signaling to the UE the MSI of the target eNB from the target eNB.

Description:
DEVICES AND METHOD OF EVOLVED MULTIMEDIA BROADCAST MULTICAST SERVICE HANDOVER

TECHNICAL FIELD

[0001] Embodiments pertain to radio access networks. Some embodiments relate to Evolved Multimedia Broadcast Multicast Services (eMBMS) handover in cellular networks, including Third Generation Partnership Project Long Term Evolution (3GPP LTE) networks and LTE advanced (LTE- A) networks as well as 4 th generation (4G) networks and 5 th generation (5G) networks

BACKGROUND

[0002] With the increase in different types of devices communicating over networks to servers and other computing devices, usage of 3GPP LTE systems has increased. In particular, as the number and complexity of user equipment (UEs) has grown, users have demanded extended functionality and enhanced and varied applications. While the demand for telephony and messaging services has remained steady, the demand for data-intensive applications such as video streaming has continued to increase, particularly stressing network resources. To combat this, unicast services (one-to-one transmissions to a particular UE), broadcast (one -to-many transmissions to all UEs) and multicast services (one -to-many transmissions to all UEs of a specific group of UEs) have been developed. Multicast services such as eMBMS become more efficient with increasing group size, making more efficient use of the available spectrum than unicast, but have a large setup time and are thus undesirable for low latency communications.

[0003] eMBMS, like unicast services, also may suffer from issues related to handover. In particular, when handover of the UE occurs between source and target cells (also referred to herein as evolved eNodeBs (eNBs)) while the UE is receiving eMBMS services, the eMBMS services may be interrupted as the UE has neither eMBMS subframe allocation of the target cell nor information of whether or not the target subframe supports the eMBMS services currently being received by the UE. It would therefore be desirable to enable UE handover permitting continuous eMBMS service. BRIEF DESCRIPTION OF THE FIGURES

[0004] In the figures, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0005] FIG. 1 shows an example of a portion of an end-to-end network architecture of an LTE network with various components of the network in accordance with some embodiments.

[0006] FIG. 2 illustrates components of a UE in accordance with some embodiments.

[0007] FIG. 3 illustrates a block diagram of a communication device in accordance with some embodiments.

[0008] FIG. 4 illustrates another block diagram of a communication device in accordance with some embodiments.

[0009] FIG. 5 illustrates an eMBMS handover flow in accordance with some embodiments.

[0010] FIG. 6 illustrates another eMBMS handover flow in accordance with some embodiments.

[0011] FIG. 7 illustrates a flowchart of a method of UE handover in accordance with some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. [0013] FIG. 1 shows an example of a portion of an end-to-end network architecture of a Long Term Evolution (LTE) network with various components of the network in accordance with some embodiments. As used herein, an LTE network refers to both LTE and LTE Advanced (LTE-A) networks as well as other versions of LTE networks to be developed. The network 100 may comprise a radio access network (RAN) (e.g., as depicted, the E-UTRAN or evolved universal terrestrial radio access network) 101 and core network 120 (e.g., shown as an evolved packet core (EPC)) coupled together through an SI interface 115. For convenience and brevity, only a portion of the core network 120, as well as the RAN 101, is shown in the example.

[0014] The core network 120 may include a mobility management entity

(MME) 122, serving gateway (serving GW) 124, and packet data network gateway (PDN GW) 126. The RAN 101 may include evolved node Bs (eNBs) 104 (which may operate as base stations) for communicating with user equipment (UE) 102. The eNBs 104 may include macro eNBs and low power (LP) eNBs. The eNBs 104 and UEs 102 may employ the eMBMS handover services as described herein.

[0015] The MME 122 may be similar in function to the control plane of legacy Serving GPRS Support Nodes (SGSN). The MME 122 may manage mobility aspects in access such as gateway selection and tracking area list management. The serving GW 124 may terminate the interface toward the RAN 101, and route data packets between the RAN 101 and the core network 120. In addition, the serving GW 124 may be a local mobility anchor point for inter-eNB handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement. The serving GW 124 and the MME 122 may be implemented in one physical node or separate physical nodes.

[0016] The PDN GW 126 may terminate a SGi interface toward the packet data network (PDN). The PDN GW 126 may route data packets between the EPC 120 and the external PDN, and may perform policy enforcement and charging data collection. The PDN GW 126 may also provide an anchor point for mobility devices with non-LTE access. The external PDN can be any kind of IP network, as well as an IP Multimedia Subsystem (IMS) domain. The PDN GW 126 and the serving GW 124 may be implemented in a single physical node or separate physical nodes.

[0017] The eNBs 104 (macro and micro) may terminate the air interface protocol and may be the first point of contact for a UE 102. In some embodiments, an eNB 104 may fulfill various logical functions for the RAN 101 including, but not limited to, RNC (radio network controller functions) such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. In accordance with embodiments, UEs 102 may be configured to communicate orthogonal frequency division multiplexed (OFDM) communication signals with an eNB 104 over a multicarrier communication channel in accordance with an OFDMA communication technique. The OFDM signals may comprise a plurality of orthogonal subcarriers.

[0018] The S 1 interface 1 15 may be the interface that separates the RAN 101 and the EPC 120. It may be split into two parts: the S l-U, which may carry traffic data between the eNBs 104 and the serving GW 124, and the Sl-MME, which may be a signaling interface between the eNBs 104 and the MME 122. The X2 interface may be the interface between eNBs 104. The X2 interface may comprise two parts, the X2-C and X2-U. The X2-C may be the control plane interface between the eNBs 104, while the X2-U may be the user plane interface between the eNBs 104.

[0019] With cellular networks, LP cells may be typically used to extend coverage to indoor areas where outdoor signals do not reach well, or to add network capacity in areas with dense usage. In particular, it may be desirable to enhance the coverage of a wireless communication system using cells of different sizes, macrocells, microcells, picocells, and femtocells, to boost system performance. The cells of different sizes may operate on the same frequency band, or may operate on different frequency bands with each cell operating in a different frequency band or only cells of different sizes operating on different frequency bands. As used herein, the term low power (LP) eNB refers to any suitable relatively low power eNB for implementing a smaller cell (smaller than a macro cell) such as a femtocell, a picocell, or a microcell. Femtocell eNBs may be typically provided by a mobile network operator to its residential or enterprise customers. A femtocell may be typically the size of a residential gateway or smaller and generally connect to a broadband line. The femtocell may connect to the mobile operator's mobile network and provide extra coverage in a range of typically 30 to 50 meters. Thus, a LP eNB might be a femtocell eNB since it is coupled through the PDN GW 126. Similarly, a picocell may be a wireless communication system typically covering a small area, such as in- building (offices, shopping malls, train stations, etc.), or more recently in- aircraft. A picocell eNB may generally connect through the X2 link to another eNB such as a macro eNB through its base station controller (BSC)

functionality. Thus, LP eNB may be implemented with a picocell eNB since it may be coupled to a macro eNB via an X2 interface. Picocell eNBs or other LP eNBs may incorporate some or all functionality of a macro eNB. In some cases, this may be referred to as an access point base station or enterprise femtocell.

[0020] Communication over an LTE network may be split up into 10ms frames, each of which may contain ten 1ms subframes. Each subframe of the frame, in turn, may contain two slots of 0.5ms. Each subframe may be used for uplink (UL) communications from the UE to the eNB or downlink (DL) communications from the eNB to the UE. In one embodiment, the eNB may allocate a greater number of DL communications than UL communications in a particular frame. The eNB may schedule transmissions over a variety of frequency bands (fi and Ϊ2). The allocation of resources in subframes used in one frequency band and may differ from those in another frequency band. Each slot of the subframe may contain 6-7 symbols, depending on the system used. In one embodiment, the subframe may contain 12 subcarriers. A downlink resource grid may be used for downlink transmissions from an eNB to a UE, while an uplink resource grid may be used for uplink transmissions from a UE to an eNB or from a UE to another UE. The resource grid may be a time-frequency grid, which is the physical resource in the downlink in each slot. The smallest time-frequency unit in a resource grid may be denoted as a resource element (RE). Each column and each row of the resource grid may correspond to one OFDM symbol and one OFDM subcarrier, respectively. The resource grid may contain resource blocks (RBs) that describe the mapping of physical channels to resource elements and physical RBs (PRBs). A PRB may be the smallest unit of resources that can be allocated to a UE. A resource block may be 180 kHz wide in frequency and 1 slot long in time. In frequency, resource blocks may be either 12 x 15 kHz subcarriers or 24 x 7.5 kHz subcarriers wide. For most channels and signals, 12 subcarriers may be used per resource block, dependent on the system bandwidth. In Frequency Division Duplexed (FDD) mode, both the uplink and downlink frames may be 10ms and frequency (full-duplex) or time (half-duplex) separated. In Time Division Duplexed (TDD), the uplink and downlink subframes may be transmitted on the same frequency and are multiplexed in the time domain. The duration of the resource grid 400 in the time domain corresponds to one subframe or two resource blocks. Each resource grid may comprise 12 (subcarriers) * 14 (symbols) =168 resource elements.

[0021] There may be several different physical downlink channels that are conveyed using such resource blocks, including the physical downlink control channel (PDCCH) and the physical downlink shared channel (PDSCH). Each subframe may be partitioned into the PDCCH and the PDSCH. The PDCCH may normally occupy the first two symbols of each subframe and carries, among other things, information about the transport format and resource allocations related to the PDSCH channel, as well as H-ARQ information related to the uplink shared channel. The PDSCH may carry user data and higher layer signaling to a UE and occupy the remainder of the subframe. Typically, downlink scheduling (assigning control and shared channel resource blocks to UEs within a cell) may be performed at the eNB based on channel quality information provided from the UEs to the eNB, and then the downlink resource assignment information may be sent to each UE on the PDCCH used for (assigned to) the UE. The PDCCH may contain downlink control information (DCI) in one of a number of formats that tell the UE how to find and decode data, transmitted on PDSCH in the same subframe, from the resource grid. The DCI format may provide details such as number of resource blocks, resource allocation type, modulation scheme, transport block, redundancy version, coding rate etc. Each DCI format may have a cyclic redundancy code (CRC) and be scrambled with a Radio Network Temporary Identifier (RNTI) that identifies the target UE for which the PDSCH is intended. Use of the UE-specific RNTI may limit decoding of the DCI format (and hence the corresponding PDSCH) to only the intended UE.

[0022] The network 100 may also contain network elements that provide eMBMS services to the UEs 102 in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area using a single frequency across a geographically limited cluster of eNBs. The same eMBMS signal may be transmitted synchronously by multiple eNBs 104 within the same MBSFN area. The UE 102 may combine the signals to obtain a higher signal-to-noise ratio. eMBMS allows multimedia content to be sent once from a single transmission and received by multiple UEs 102. eMBMS may include distribution of a variety of data, including video, music, software, news, weather, ads and other data to large number of UEs 102. The content can be live or preloaded for later use. eMBMS may be used to reduce overhead in transmitting to multiple UEs 102; the extent of reduction depends on the number of UEs 102 in the MBSFN area receiving the same content and the fraction of the entire network traffic that is multicast.

[0023] The elements in the network 100 used to provide eMBMS services may include a Multi-call/multicast Coordination Entity (MCE) 132, a MBSFN Gateway (MBSFN GW) 134 and a Broadcast/Multicast Service Center (BM-SC) 136. The MBSFN area may include a group of cells coordinated to achieve an MBSFN transmission, which may simultaneously transmit identical signals from multiple cells, to be seen as a single transmission by the UE 102 in the MBSFN area. Each eNB 104 may be able to belong to different MBSFN areas having different MBMS transmissions (each of which is synchronized within the associated MBSFN area).

[0024] eMBMS services may be multiplexed in time inside MBSFN subframes with eMBMS control information used to inform UEs 102 about eMBMS scheduling. In the MBSFN area, the Multicast Traffic Channel (MTCH) may be used to transmit traffic data of eMBMS services and the Multicast Control Channel (MCCH) may be used to transmit control information associated to all MTCHs transmitted in the MBSFN area. Both MTCH and MCCH may be mapped into the multicast channel (MCH), which is mapped into the physical multicast channel (PMCH). The information carried by MCCH may include subframe allocation and Modulation Coding Scheme (MCS) for a MBMS session.

[0025] A one-to-one mapping may exist between a MBSFN area and

MCCH. The eNB 104 may transmit eMBMS information through the broadcast control channel (BCCH) via System Information Blocks (SIBs). Of the SIBs transmitted by the eNB 104, SIB2 and SIB 13 may contain eMBMS information; SIB2 may indicate to the UE which subframes are reserved for MBSFN, while SIB 13 may indicate how many MBSFN areas are configured in an eNB as well as which subframes and the MCS are used by the MCCH of each MBSFN area. MCCHs may be periodically transmitted by all eNBs 104 within an MBSFN area over one of the MBSFN-capable subframes, broadcasted over the SIB 13. A maximum of six subframes in each radio frame may be MBSFN subframes; subframes 0, 4-5 and 9 are reserved for unicast transmission.

[0026] The MCCH may indicate the scheduling of the PMCHs within the MBSFN subframes related to the MBSFN area through the Common Subframe Allocation (CSA) and the PMCH-InfoList. The CSA may indicate which subframes are reserved for all the MCHs of an MBSFN area, while the PMCH- InfoList may indicate how the subframes are shared among those MCHs. The PMCH-InfoList may report the MCS of the eMBMS services related to each MCH. Each MCH can multiplex several eMBMS services. To identify a specific eMBMS service, the PMCH-InfoList may define all the eMBMS ongoing sessions (identified by MTCH). The PMCH-InfoList may indicate a period of time known as MCH Scheduling Period (MSP) where the associated MTCHs are multiplexed. The MTCH multiplexing may be indicated in the first subframe of each MSP using a medium access control (MAC) control element called MCH Scheduling Information (MSI). In addition, all eNBs providing eMBMS service may periodically transmit a Service Description Channel (SDCH) to permit attached UEs to receive updated service-description information.

[0027] As above, the MCCH may be transmitted in MCCH subframes indicated via RRC signaling (in SIB2/13) every MCCH repetition period. When the MCCH is modified, due to either a Session Start or the presence of an MBMS counting request message, the modification may be transmitted to the UEs 102 using a periodic notification in a modification period preceding the MCCH change, in MBSFN subframes configured for notification. The DCI format 1C with a MBMS RNTI and a MCCHChangeNotification field indicating the MBSFN areas in which the MCCH changes may be used for notification. The UE 102 may monitor one or more of the notification subframes in a modification period and, when a change notification is received, acquire the MCCH at the next modification period boundary.

[0028] While the BCCH may indicate where the MCCH can be found, as above, SIB2 which subframes are reserved for MBSFN (while the MCCH may indicate whether or not a particular MBMS service is available). Specifically, SIB2 may contain a MBSFN-SubframeConfigList field that may indicate the MBSFN subframe configuration, including the allocation period

(radioframeAllocationPeriod, 2 n values), frame offset

(radioframeAllocationOffset, 1-7 values) and subframe allocation (1 or 4 frames). Radio frames meeting: SFN mod radioframeAllocationPeriod = radioframeAllocationOffset may be allocated for MBSFN, in which subframes 1-3 and 6-8 may be allocated for MBSFN (as indicate above subframes 0, 4-5 and 9 are reserved for unicast transmission).

[0029] Similarly, SIB 13 may be used to notify the UE 102 of other eMBMS information, including the scheduling of the MCCH for multi-cell transmission on the MCH, the MCCH modification period, repetition period radio frame offset, and subframe allocation and an MCS that applies to the subframes indicated for MCCH scheduling and for the first subframe of all MCH scheduling periods in that MBSFN area. SIB 13 also may be used for all MCCH to configure the position of the MCCH change notification subframe and the number of occasions monitored by the UE 102 and indicate the mapping between the PDCCH bit(s) carried in the notification and the MCCH(s).

[0030] The MCE 132 is a logical function that may be in a separate element in the network 100 or may reside in another network element, such as the eNB 104. The MCE 132 may perform admission control, allocation of radio resources throughout the MBSFN, MBMS session control signaling, counting and acquisition of counting results for MBMS services, controlling suspension and resumption of a MBMS session within the MBSFN area, as well as making decisions on radio configuration. The M3 interface between the MCE 132 and the MME 122 may carry control signaling rather than data. The M3 interface may carry MBMS Session Control Signaling (e.g., MBMS Session Start/Stop) from the MME 122 to the MCE 132. Similarly, the M2 interface between the MCE 132 and the eNB 104 may carry the control signaling rather than data and may allow for transmission of MBMS Session Control Signaling and Radio Configuration data from the MCE 132 to the eNB 104.

[0031] The MBSFN GW 134 may transmit MBMS packets to all eNBs

104 that are part of the eMBMS service using IP multicast. The MBSFN GW 134 may perform MBMS session control signaling (session start/update/stop) toward the E-UTRAN 101 using an interface to the MME 122. The MBSFN GW 134 may be a separate element in the network 100 or may be integrated into another network element, such as the S-GW 124. The Ml interface between the MBMS GW 124 and the eNB 104 is a user plane interface that uses IP multicast to deliver the MBMS packets to the eNB 104 and does not deliver control plane information to the eNB 104.

[0032] The BM-SC 136 may provide various MBMS-related functionality. This functionality may include scheduling of an MBMS service, announcing the MBMS service to the UEs 102, authorization of UEs 102, allocation of bearer service identification, and initiation and termination of MBMS bearer resources. The BM-SC 136 may also be a direct interface point for content providers. The BM-SC 136 may also terminate the SYNC protocol over the Ml interface used to synchronize the radio interface transmission of the same data from all eNBs 104 in the MBSFN area. The eNB 104 may support the SYNC protocol with the BM-SC 136. In the SYNC protocol, SYNC packet may contain a time stamp indicating the start time of a synchronization sequence. The eNB 104 may join an IP multicast, terminate the multicast control channel and indicate to the UEs 102 a multicast session start/stop. The BM-SC 136 may provide a unique identifier Temporary Mobile Group Identity (TMGI) to identify each MBMS service within the PLMN when establishing the eMBMS service.

[0033] In operation, to start an MBMS service, the MME 122 may request an MBMS service from the MCE 132 in a MBMS Session Start Request and receive a MBMS Session Start Response from the MCE 132. The MCE 132 may indicate to the eNB 104 in a MBMS Session Start Request that an MBMS service is desired and receive a MBMS Session Start Response from the eNB 104. The MCE 132 may subsequently transmit to the eNB 104 MBMS scheduling information. The eNB 104 may transmit an MBMS Session Start message to the UEs 102, join the IP multicast group for the MBMS service and transmit the synchronized MBMS user data to the UEs 102.

[0034] Similarly, to terminate an existing MBMS service, the MME 122 may transmit to the MCE 132 a MBMS Session Stop Request and receive a MBMS Session Stop Response from the MCE 132. The MCE 132 may indicate to the eNB 104 in a MBMS Session Stop Request that termination of the MBMS session is desired and receive a MBMS Session Stop Response from the eNB 104. The MCE 132 may subsequently transmit to the eNB 104 MBMS scheduling information. The eNB 104 may transmit an MBMS Session Stop message to the UEs 102, and transmit an RRC Release message to the UEs 102 before leaving the IP multicast group.

[0035] Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. FIG. 2 illustrates components of a UE in accordance with some embodiments. At least some of the components shown may be used in an eNB or MME, for example, such as the UE 102 or eNB 104 shown in FIG. 1. The UE 200 and other components may be configured to use an eMBMS handover procedure as described herein. The UE 200 may be one of the UEs 102 shown in FIG. 1 and may be a stationary, non-mobile device or may be a mobile device. In some embodiments, the UE 200 may include application circuitry 202, baseband circuitry 204, Radio Frequency (RF) circuitry 206, front-end module (FEM) circuitry 208 and one or more antennas 210, coupled together at least as shown. At least some of the baseband circuitry 204, RF circuitry 206, and FEM circuitry 208 may form a transceiver. In some embodiments, other network elements, such as the eNB may contain some or all of the components shown in FIG. 2.

Other of the network elements, such as the MME, may contain an interface, such as the S 1 interface, to communicate with the eNB over a wired connection regarding the UE. [0036] The application or processing circuitry 202 may include one or more application processors. For example, the application circuitry 202 may include circuitry such as, but not limited to, one or more single-core or multi- core processors. The processor(s) may include any combination of general- purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

[0037] The baseband circuitry 204 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 204 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 206 and to generate baseband signals for a transmit signal path of the RF circuitry 206. Baseband processing circuity 204 may interface with the application circuitry 202 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 206. For example, in some embodiments, the baseband circuitry 204 may include a second generation (2G) baseband processor 204a, third generation (3G) baseband processor 204b, fourth generation (4G) baseband processor 204c, and/or other baseband processor(s) 204d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 204 (e.g., one or more of baseband processors 204a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 206. The radio control functions may include, but are not limited to, signal modulation/demodulation,

encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 204 may include Fast-Fourier Transform (FFT), precoding, and/or constellation

mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 204 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[0038] In some embodiments, the baseband circuitry 204 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 204e of the baseband circuitry 204 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 204f. The audio DSP(s) 204f may be include elements for

compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 204 and the application circuitry 202 may be implemented together such as, for example, on a system on a chip (SOC).

[0039] In some embodiments, the baseband circuitry 204 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 204 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network

(WPAN). Embodiments in which the baseband circuitry 204 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. In some embodiments, the device can be configured to operate in accordance with communication standards or other protocols or standards, including Institute of Electrical and Electronic Engineers (IEEE) 802.16 wireless technology (WiMax), IEEE 802.1 1 wireless technology (WiFi) including IEEE 802 ad, which operates in the 60 GHz millimeter wave spectrum, various other wireless technologies such as global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE radio access network (GERAN), universal mobile telecommunications system (UMTS), UMTS terrestrial radio access network (UTRAN), or other 2G, 3G, 4G, 5G, etc. technologies either already developed or to be developed.

[0040] RF circuitry 206 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 206 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 206 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 208 and provide baseband signals to the baseband circuitry 204. RF circuitry 206 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 204 and provide RF output signals to the FEM circuitry 208 for transmission.

[0041] In some embodiments, the RF circuitry 206 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 206 may include mixer circuitry 206a, amplifier circuitry 206b and filter circuitry 206c. The transmit signal path of the RF circuitry 206 may include filter circuitry 206c and mixer circuitry 206a. RF circuitry 206 may also include synthesizer circuitry 206d for synthesizing a frequency for use by the mixer circuitry 206a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 206a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 208 based on the synthesized frequency provided by synthesizer circuitry 206d. The amplifier circuitry 206b may be configured to amplify the down-converted signals and the filter circuitry 206c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 204 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 206a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0042] In some embodiments, the mixer circuitry 206a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 206d to generate RF output signals for the FEM circuitry 208. The baseband signals may be provided by the baseband circuitry 204 and may be filtered by filter circuitry 206c. The filter circuitry 206c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0043] In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g.,

Hartley image rejection). In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 206a of the receive signal path and the mixer circuitry 206a of the transmit signal path may be configured for super-heterodyne operation.

[0044] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 206 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 204 may include a digital baseband interface to communicate with the RF circuitry 206.

[0045] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[0046] In some embodiments, the synthesizer circuitry 206d may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 206d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

[0047] The synthesizer circuitry 206d may be configured to synthesize an output frequency for use by the mixer circuitry 206a of the RF circuitry 206 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 206d may be a fractional N/N+l synthesizer.

[0048] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 204 or the applications processor 202 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a lookup table based on a channel indicated by the applications processor 202.

[0049] Synthesizer circuitry 206d of the RF circuitry 206 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DPA). In some embodiments, the DMD may be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

[0050] In some embodiments, synthesizer circuitry 206d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLo). In some embodiments, the RF circuitry 206 may include an IQ/polar converter.

[0051] FEM circuitry 208 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 210, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 206 for further processing. FEM circuitry 208 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 206 for transmission by one or more of the one or more antennas 210.

[0052] In some embodiments, the FEM circuitry 208 may include a

TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 206). The transmit signal path of the FEM circuitry 208 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 206), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 210.

[0053] In some embodiments, the UE 200 may include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface as described in more detail below. In some embodiments, the UE 200 described herein may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), or other device that may receive and/or transmit information wirelessly. In some embodiments, the UE 200 may include one or more user interfaces designed to enable user interaction with the system and/or peripheral component interfaces designed to enable peripheral component interaction with the system. For example, the UE 200 may include one or more of a keyboard, a keypad, a touchpad, a display, a sensor, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, a power supply interface, one or more antennas, a graphics processor, an application processor, a speaker, a microphone, and other I/O components. The display may be an LCD or LED screen including a touch screen. The sensor may include a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite.

[0054] The antenna 210 may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas 210 may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result.

[0055] Although the UE 200 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio- frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements.

[0056] Embodiments may be implemented in one or a combination of hardware, firmware and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read- only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

[0057] FIG. 3 is a block diagram of a communication device in accordance with some embodiments. The device may be a UE or eNB, for example, such as the UE 102 or eNB 104 shown in FIG. 1 that may be configured to track the UE as described herein. The communication device 300 may include physical layer circuitry 302 for transmitting and receiving signals using one or more antennas 301. The communication device 300 may also include medium access control layer (MAC) circuitry 304 for controlling access to the wireless medium. The communication device 300 may also include processing circuitry 306, such as one or more single-core or multi-core processors, and memory 308 arranged to perform the operations described herein. The physical layer circuitry 302, MAC circuitry 304 and processing circuitry 306 may handle various radio control functions that enable communication with one or more radio networks compatible with one or more radio technologies. The radio control functions may include signal modulation, encoding, decoding, radio frequency shifting, etc. For example, similar to the device shown in FIG. 2, in some embodiments, communication may be enabled with one or more of a WMAN, a WLAN, and a WPAN. In some embodiments, the communication device 300 can be configured to operate in accordance with 3 GPP standards or other protocols or standards, including WiMax, WiFi, GSM, EDGE, GERAN, UMTS, UTRAN, or other 3G, 3G, 4G, 5G, etc. technologies either already developed or to be developed.

[0058] The antennas 301 may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some MIMO embodiments, the antennas 301 may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result.

[0059] Although the communication device 300 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including DSPs, and/or other hardware elements. For example, some elements may comprise one or more

microprocessors, DSPs, FPGAs, ASICs, RFICs and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements. Embodiments may be implemented in one or a combination of hardware, firmware and software.

Embodiments may also be implemented as instructions stored on a computer- readable storage device, which may be read and executed by at least one processor to perform the operations described herein.

[0060] FIG. 4 illustrates another block diagram of a communication device in accordance with some embodiments. In alternative embodiments, the communication device 400 may operate as a standalone device or may be connected (e.g., networked) to other communication devices. In a networked deployment, the communication device 400 may operate in the capacity of a server communication device, a client communication device, or both in server- client network environments. In an example, the communication device 400 may act as a peer communication device in peer-to-peer (P2P) (or other distributed) network environment. The communication device 400 may be a UE, eNB, AP, STA, PC, a tablet PC, a STB, a PDA, a mobile telephone, a smart phone, a web appliance, a network router, switch or bridge, or any

communication device capable of executing instructions (sequential or otherwise) that specify actions to be taken by that communication

device. Further, while only a single communication device is illustrated, the term "communication device" shall also be taken to include any collection of communication devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

[0001] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a communication device readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[0002] Accordingly, the term "module" is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time.

[0003] Communication device (e.g., computer system) 400 may include a hardware processor 402 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 404 and a static memory 406, some or all of which may communicate with each other via an interlink (e.g., bus) 408. The

communication device 400 may further include a display unit 410, an alphanumeric input device 412 (e.g., a keyboard), and a user interface (UI) navigation device 414 (e.g., a mouse). In an example, the display unit 410, input device 412 and UI navigation device 414 may be a touch screen display. The communication device 400 may additionally include a storage device (e.g., drive unit) 416, a signal generation device 418 (e.g., a speaker), a network interface device 420, and one or more sensors 421 , such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The communication device 400 may include an output controller 428, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0004] The storage device 416 may include a communication device readable medium 422 on which is stored one or more sets of data structures or instructions 424 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 424 may also reside, completely or at least partially, within the main memory 404, within static memory 406, or within the hardware processor 402 during execution thereof by the communication device 400. In an example, one or any combination of the hardware processor 402, the main memory 404, the static memory 406, or the storage device 416 may constitute communication device readable media.

[0005] While the communication device readable medium 422 is illustrated as a single medium, the term "communication device readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 424.

[0006] The term "communication device readable medium" may include any medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 400 and that cause the communication device 400 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting communication device readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of communication device readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access Memory (RAM); and CD-ROM and DVD-ROM disks. In some examples, communication device readable media may include non-transitory communication device readable media. In some examples, communication device readable media may include communication device readable media that is not a transitory propagating signal.

[0007] The instructions 424 may further be transmitted or received over a communications network 426 using a transmission medium via the network interface device 420 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.1 1 family of standards known as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, among others. In an example, the network interface device 420 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 426. In an example, the network interface device 420 may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), MIMO, or multiple-input single-output (MISO) techniques. In some examples, the network interface device 420 may wirelessly communicate using Multiple User MIMO techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the communication device 400, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

[0061] As indicated above, eMBMS sessions may encounter service interruptions when handover occurs between source and target eNBs. This is due to the UE having to wait to receive all eMBMS messaging from the target eNB after handover occurs as the UE may not have the eMBMS subframe allocation information of the target eNB for interested eMBMS services. The 3 GPP specification moreover does not specify how the UE may be able to continue receiving eMBMS services from the target eNB. This may be of particular import when the handover occurs between eNBs in different MBSFN areas, when the available eMBMS services may differ between the eNBs and/or the subframes used for the eMBMS services (or particular eMBMS services subscribed to by the UE) differ.

[0062] Additionally, the 3GPP specification does not specify the manner in which the UE is able to read SIB2 messaging. This may be an issue because the MBSFN subframe allocation may differ between the source and target eNBs, the SIB2 allocation transmitted by the target eNB may fall into the MBSFN subframe allocation of the source eNB. In this case, when handover occurs the UE may for service continuity attempt to receive eMBMS service based on the MBSFN subframe allocation of the source eNB instead of the SIB2 allocation. The UE may thus be unable to receive unicast-related signaling from the target eNB at this point in time.

[0063] Thus, the source and target eNBs may provide the same eMBMS service, one in which the UE receives (or is interested in receiving) from the source eNB. However, the eMBMS service may have different MBSFN subframe allocations dependent on whether the source or target eNB is transmitting the eMBMS service. The UE may continue to use the source eNB MBSFN subframe allocation instead of the target eNB MBSFN subframe allocation the UE has not yet obtained the target eNB eMBMS configuration information. The UE may thus experience a significant eMBMS service interruption as the UE may not be able to continue receiving eMBMS service from the target eNB until after receiving all eMBMS signaling related to the desired eMBMS service. Alternatively, the UE may attempt to receive eMBMS services from the target eNB using subframes of the target eNB that are not allocated for eMBMS service but which were part of the source eNB MBSFN allocation. The SIB2 allocation may also fall into one of subframes from which the UE is trying to receive eMBMS services. As the UE attempts to decode either unicast or broadcast data in a particular subframe, the UE may not be able to receive that SIB2 broadcast from the target eNB, resulting in an extended eMBMS service outage until the UE is eventually able to successfully receive the SIB2 broadcast from the target eNB.

[0064] In some embodiments, the network 100 may provide the MBSFN allocations and eMBMS service information in a message prior to handover of the UE 102 from the source eNB 104 to the target eNB 104 being completed. For example, in some embodiments the eMBMS information may be contained in an RRCConnectionReconfiguration message used to trigger handover of the UE 102 from the source eNB 104 to the target eNB 104. In such embodiments the UE 102 may receive and use the eMBMS information including the eMBMS subframe allocations of the target eNB 104 as soon as handover is completed and is thus able to continue to receive full eMBMS services during the handover procedure. Embodiments of such handover procedures are shown and described in more detail below.

[0065] FIG. 5 illustrates an eMBMS handover flow in accordance with some embodiments. The UE 502, source eNB 504 and target eNB 506 may be those shown in one or more of FIGS. 1-4. In some embodiments, the same MTCH data (or eMBMS service) may be provided by the source eNB 504 and target eNB 506. In some embodiments, the MTCH subframe allocation of the source eNB 504 and the target eNB 506 may be independent of each other. Thus, in some embodiments, the MTCH subframe allocation may be different between the source eNB 504 and target eNB 506. For example, the MTCH subframe allocation for a particular eMBMS service may occur in subframes 2, 3, 6, 7 of System Frame number (SFN) 0 in the source eNB 504 and occur in subframes 1, 2, 3, 6 of SFN 2 in the target eNB 506. Moreover, although subframes 1-3 and 6-8 may be allocated for eMBMS service in all SFNs of the source eNB 504, this may not be the case in the target eNB 506. For example, all subframes in SFN 0 and all subframes except a single subframe (say subframe 7) in SFN 1 in the target eNB 506 may be allocated as unicast rather than eMBMS configured subframes.

[0066] Typically, if the UE 502 is unable to obtain the MTCH information of the target eNB 506 eMBMS subframe allocations during the handover procedure, the UE 502 may still for continuity reasons attempt to use the eMBMS configuration of the source eNB 504 when attached to the target eNB 506. In some embodiments, the MTCH configurations of the source eNB 504 and target eNB 506 may be the same (at least for the eMBMS services used by the UE 502). However, it is more likely that the eMBMS subframes between the source eNB 504 and target eNB 506 are different, leading to the UE 502 being unable to receive the eMBMS service and causing an outage until the UE 502 is able to receive and decode the full eMBMS messaging (SIB2 and SIB 13) from the target eNB 506. The embodiment of FIG. 5, however, may be able to solve both the issue of eMBMS service continuity where the MTCH

configurations of the source eNB 504 and target eNB 506 are different and the SIB2 of the target eNB 506 occurs in one of the eMBMS subfirame allocations of the source eNB 504 but the UE 502 is attached to the target eNB 506.

[0067] Specifically, as shown in FIG. 5, the UE 502 may transmit a list of TMGIs to identify each MBMS service to which the UE 502 is subscribed (and perhaps to which the UE 502 is interested in subscribing). The UE 502 may transmit the ongoing-TMGI list in, for example, a measurement report 512 to the source eNB 502. The measurement report 512 may comprise a measurement of reference signals in one or more channels providing unicast or eMBMS transmissions to the UE 502 from the source eNB 504. The channels may include carriers in the licensed spectrum and perhaps carriers in the unlicensed spectrum when carrier aggregation is used. The measurement report may include, for example, the signal-to-noise ratio (SNR), the signal-to- interference plus noise ratio (SINR) of the reference signals, the received signal strength (RSS), the bit- error-rate (BER) before or after the channel decoder or a Channel Quality Indication (CQI) report carried by the PUCCH, among others. The UE 502 may transmit to the source eNB 504 the ongoing-TMGI list in each measurement report 512 or periodically, e.g., providing the ongoing-TMGI list every predetermined number of measurement reports 512. The periodicity may be constant or may depend on the measurements such that as the channel quality decreases, and thus handover becomes more likely, the ongoing-TMGI list is transmitted in the measurement reports 512 with increasing frequency.

[0068] In some embodiments, the UE 502 may autonomously determine whether or not to transmit the ongoing-TMGI list in the measurement report 512. In some embodiments, the source eNB 504 may solicit the ongoing-TMGI list in one or more succeeding measurement reports 512 such as the next measurement report 512. In embodiments in which the source eNB 504 transmits a request for the ongoing-TMGI list, the number of succeeding measurement reports 512 in which the source eNB 504 requests the ongoing-TMGI list may increase with decreasing channel conditions as determined by the last measurement report 512. Thus, the source eNB 504 may request the ongoing-TMGI list in only the next measurement report 512 if channel conditions are good, but increase to request the ongoing-TMGI list in the next n measurement reports 512 as the channel conditions deteriorate. In some embodiments, the UE 502 may provide the ongoing-TMGI list in dedicated signaling to the source eNB 504 instead of, or in addition to, the measurement report 512.

[0069] The source eNB 504 may, in response to receiving the measurement report 512, determine that handover of the UE 502 to the target eNB 506 is to occur. For example, for an Intra-LTE (Intra-MME/SGW) handover using the X2 interface, the source eNB 504 may transmit a resource status request message to the target eNB 506 to determine the load on the target eNB 506. Based on a resource status response message received from the target eNB 506 in response to the resource status request message, the source eNB 504 may decide to continue the handover procedure to the target eNB 506 using the X2 interface. The source eNB 504 may transmit a handover request message to the target eNB 506, passing information to prepare the handover at the target side. This information may include UE Context, which includes the Security Context, and RBContext, including e-Radio Access Bearer (E-RAB) to RB Mapping, and the target cell info as well as the TMGI list. The target eNB 506 may check for resource availability and, if available, reserve the resources and transmit to the source eNB 504 a handover request ACK message including a transparent container to be sent to the UE 502 as an RRC message to perform the handover and the MBMS information of the target eNB 506. The container may include a new C-RNTI, target eNB security algorithm identifiers for selected security algorithms, a dedicated RACH preamble, and other parameters such as access parameters, SIBs, etc.

[0070] The source eNB 504 may then transmit an

RRCConnectionReconfiguration message 514 to the UE 502 to initiate handover of the UE 502 to the target eNB 506. The RRCConnectionReconfiguration message 514 may comprise eMBMS specific parameters that may normally be obtained by the UE 502 from the target eNB 506 after the UE 502 has attached to the target eNB 506. The source eNB 504 may transmit an eNB status transfer message to the target eNB 506 to convey the PDCP and HFNstatus of the E- PvABs. The source eNB 504 may start forwarding the downlink data packets to the target eNB 506 for all the data bearers established in the target eNB 506 during processing of the handover request message. The UE 502 may attempt to access the target eNB 506 cell using the non-contention-based Random Access Procedure. If the UE 502 succeeds in accessing the target cell, the UE 502 may transmit an RRCConnectionReconfigurationComplete message to the target eNB 506. The target eNB 506 may transmit a path switch request message to the MME to inform the MME that the UE 502 has changed cells, including the TAI+ECGI of the target. The MME may determine whether or not the SGW can continue to serve the UE 502. The MME may transmit to the SGW a modify bearer request message that includes the eNodeB address and TEIDs for downlink user plane for the accepted EPS bearers to the SGW. If the PDN GW requested the UE's location info, the MME may also include a User Location Information IE in the modify bearer request message. The SGW may transmit downlink packets to the target eNB 506 using the newly received addresses and TEIDs, as well as sending a modify bearer response to the MME. The SGW may transmit one or more packets on the old path to the source eNB 504 and then can release user plane resources toward the source eNB 504. The MME may respond to the target eNB 506 with a path switch request ACK message to notify the completion of the handover. The target eNB 506 may now request the source eNB 504 to release the resources using an X2 UE context release message.

[0071] In some embodiments the RRCConnectionReconfiguration message 514 may contain complete eMBMS services information. In this embodiment, the RRCConnectionReconfiguration message 514 may contain SIB2-related eMBMS information (the eMBMS information carried by the SIB2), SIB 13-related eMBMS information (the eMBMS information carried by the SIB 13), and MSI and MBSFN configuration information. More specifically, the SIB2-related eMBMS information of the RRCConnectionReconfiguration message 514 may include an MBSFN Subframe Configuration list that indicates the MBSFN subframe configuration (which subframes in the target eNB 506 are reserved for MBSFN). The MBSFN Subframe Configuration list may include the allocation period, frame offset and subframe allocation. The SIB13-related eMBMS information of the RRCConnectionReconfiguration message 514 may include an MBSFN Area Information list (MBMS-AreaInfoList-r9)indicating MBSFN areas as well as which subframes and the MCS are used by the MCCH of each MBSFN area. In some embodiments, the MBSFN Area Information list may provide information of all MBSFN areas. In some embodiments, the MBSFN Area Information list may be limited to only those MBSFN areas of which the target eNB 506 is configured to be a member.

[0072] The SIB 13 -related eMBMS information in the

RRCConnectionReconfiguration message 514 may also include an eMBMS Notification Configuration (MBMS-NotificationConfig-r9) that indicates the scheduling of the MCCH for multi-cell transmission on the MCH, the MCCH modification period, repetition period radio frame offset, and subframe allocation and an MCS that applies to the subframes indicated for MCCH scheduling and for the first subframe of all MCH scheduling periods in that MBSFN area. The SIB 13 -related eMBMS information in the

RRCConnectionReconfiguration message 514 may also include the position of the MCCH change notification subframe and the number of occasions monitored by the UE 502 and indicate the mapping between the PDCCH bit(s) carried in the notification and the MCCH(s).

[0073] Regardless of whether all MBSFN areas are included or whether only the MBSFN areas associated with the target eNB 506 are included, the allocation information for each area may be provided in the

RRCConnectionReconfiguration message 514. This is to say that for each area the scheduling of the PMCHs within the MBSFN subframes related to the MBSFN area may be indicated through a CSA and common subframe allocation period and PMCH-InfoList. The CSA may indicate which subframes are reserved for all the MCHs of the MBSFN area, while the PMCH-InfoList may indicate how the subframes are shared among those MCHs. The PMCH-InfoList may report the MCS of the eMBMS services related to each MCH. The PMCH- InfoList may define all the eMBMS ongoing sessions identified by MTCH. The PMCH-InfoList may indicate the MSP. The MTCH multiplexing may be indicated in the first subframe of each MSP using the MSI.

[0074] In this case, since the source eNB 504 supplies all information of all eMBMS services offered by the target eNB 506 (and potentially those not offered if including information of an eMBMS area not associated with the target eNB 506), the source eNB 504 may determine the presence of the ongoing TMGI list in the measurement report 512 without examining the ongoing TMGI list to specifically determine the eMBMS services desired by the UE 502. Thus, the mere presence of the ongoing TMGI list in the measurement report 512 may trigger the addition of the eMBMS services information in the

RRCConnectionReconfiguration message 514. This permits the UE 502 to receive MTCHs dynamically during the handover procedure, even MTCHs that were not received before the handover procedure initiated. In addition, the UE 502 may not provide the ongoing TMGI list at all, instead merely transmitting an indication that it is receiving or intends to receive eMBMS services. However, while only existing signaling is used, as in some embodiments the

RRCConnectionReconfiguration message 514 may include all MTCH information from all configured MBSFN-areas, this may increase the signaling overhead.

[0075] To reduce the amount of overhead, in some embodiments the

MTCH information provided in the RRCConnectionReconfiguration message 514 may be limited to the eMBMS services used or desired by the UE 502. The source eNB 504 may solicit this information from the UE 502 in a request 510 for ongoing and interested TMGI information from the UE 502. The request 510 from the source eNB 504, if present, may be transmitted prior to the measurement report 512. In response to receiving the request 510, the UE 502 may provide the additional ongoing TMGI list in the measurement report 512. In some embodiments, if the request 510 is not transmitted, the UE 502 may refrain from transmitting the ongoing TMGI list in the measurement report 512. In some embodiments, the request 510 may include an indication of the number of succeeding measurement reports 512 to include the ongoing TMGI list to reduce the signaling overhead. In this case, the UE 502 may transmit the ongoing TMGI list in the next several measurement reports 512 as indicated in the request 510 without receiving an additional request 510 and thereafter refrain from transmitting the ongoing TMGI list in the measurement report 512 until a new request has been received. The ongoing TMGI list may include not only eMBMS services currently subscribed to by the UE 502, but eMBMS services that may or may not be offered by the source eNB 502 to which the UE 502 would like to subscribe.

[0076] In response to receiving the ongoing TMGI list in the measurement report 512, the source eNB 504 may include MB SFN-sub frame allocation information only for the TMGIs indicated by the UE 502 in the measurement report 512. In this case, the RRCConnectionReconfiguration message 514 may not include the SIB- 13 related information. Thus, the RRCConnectionReconfiguration message 514 may include the SIB2-related information of the MBSFN sub frame configuration list and, for each MTCH indicated by the TMGI in the ongoing TMGI list, the specific MTCH allocation information provided by the target eNB 506. Although an entirely new signal may be used between the UE 502 and the source eNB 506 (the request 510), this embodiment may significantly reduce the signaling overhead from the above embodiment as the ratio of receiving TMGIs to total transmitted TMGIs may be low. For example, the UE 502 may be interested or receiving 2-3 TMGIs of the 100s of TMGIs transmitted by the target eNB 506.

[0077] In some embodiments, to further reduce signaling overhead, only the SIB2-related information (MBSFN-subframeConfigList) may be transmitted from the source eNB 506 to the UE 506. In this case, the source eNB 506 may not transmit the request 510 the UE 506. This permits the UE 502 to obtain the MTCH configuration of the target eNB 506 but not the eMBMS information of the eMBMS services specific to those used by the UE 502. Thus, while the UE 502 may be able to obtain the SIB2 broadcast from the target eNB 506, some eMBMS service continuity issues may remain (although they may be somewhat mitigated as all of the MTCH channels may be able to be obtained by the UE 502). [0078] Whichever of the above embodiments is employed, subsequent to receiving the RRCConnectionReconfiguration message 514, the UE 502 may complete handover and may camp on the target eNB 506. This is to say that the UE 502 may receive both unicast and eMBMS traffic and control data from the target eNB 506 thereafter.

[0079] Eventually, the target eNB 506 to which the UE 502 has attached may broadcast SIB data. The target eNB 506 may broadcast different SIBs, including SIB2 and SIB 13. The UE 502, which at a minimum has obtained the unicast and eMBMS timing from the RRCConnectionReconfiguration message 514 via the SIB2-related eMBMS information, may be able to receive the SIB2 and SIB 13 information. Although the UE 502 has already obtained the SIB2- related eMBMS information and perhaps SIB 13-related eMBMS information from the RRCConnectionReconfiguration message 514, the UE 502 may receive this information again from the SIB broadcast 518 and update the SIB-related eMBMS information as indicated by the SIB broadcast 518.

[0080] Eventually, the target eNB 506 may also transmit MCCH data

520, including MBSFN Area Configuration information. Similar to the above, although the UE 502 may have already obtained the MBSFN Area Configuration information from the SIB 13 -related eMBMS information in the

RRCConnectionReconfiguration message 514, the UE 502 may receive this information again from the MCCH data 520 transmitted during the configuration subframes and may update this information as indicated.

[0081] The UE 502 may determine which eMBMS services offered by the target eNB 506 are to be received. As some of the eMBMS services available from the source eNB 504 may not be available from the target eNB 506 and some of the eMBMS services available from the target eNB 506 may not be available from the source eNB 504, the UE 502 may lose existing eMBMS services and/or obtain additional eMBMS services when handover occurs from the source eNB 504 to the target eNB 506. The UE 502, having obtained both the SIB broadcast 518 and MCCH data 520 of the target eNB 506, may subsequently receive the desired MTCH data available from the target eNB 506. [0082] FIG. 6 illustrates another eMBMS handover flow in accordance with some embodiments. The UE 602, source eNB 604 and target eNB 606 may be those shown in one or more of FIGS. 1-4. Similar to the embodiments described above in reference to FIG. 5, the UE 602 may transmit in the measurement report 612 a list of TMGIs to identify each MBMS service to which the UE 602 is subscribed and/or interested in subscribing but unavailable from the source eNB 604. The ongoing TMGI list may be solicited by the source eNB 604 or may be automatically provided in the measurement report 612.

[0083] As above, the source eNB 604 may, in response to receiving the measurement report 612, determine that handover of the UE 602 to the target eNB 606 is to occur. The source eNB 604 may then transmit an

RRCConnectionReconfiguration message 614 to the UE 602 to initiate handover of the UE 602 to the target eNB 606. The RRCConnectionReconfiguration message 614 may comprise eMBMS information described in reference to FIG. 5. Specifically, the RRCConnectionReconfiguration message 614 may include the SIB2-related eMBMS information, and may additionally contain the SIB 13- related eMBMS information, and MSI and MBSFN configuration information. Information related to all MBSFN areas or only the MBSFN areas associated with the target eNB 606 may be included in the RRCConnectionReconfiguration message 614. The MTCH information provided in the

RRCConnectionReconfiguration message 614 may contain all eMBMS services provided by the target eNB 506 or be limited to the eMBMS services used or desired by the UE 602.

[0084] In some circumstances, the MSI of the target eNB 606 may be outdated by the time the UE 602 starts receiving eMBMS information from the target eNB 606 after handover has been completed. Since MSI information is generated dynamically by the target eNB 606, and changes fairly often (e.g., every 40ms or 80ms), it may be desirable for the UE 602 to receive an updated MSI of the target eNB 606 in advance (or as soon as possible) to continue receiving a particular eMBMS service.

[0085] In general, if the MSI of the target eNB 606 is known in advance, it may be supplied to the UE 602 prior to handover being initiated or when handover is initiated. MSI information may be exchanged periodically between neighboring eNBs, whether or not they have a common MBSFN area. In some embodiments, the periodicity may change depending on the number of UEs or number of UEs specifically using or desiring eMBMS services associated with the particular eNB. In some embodiments, the periodicity may also depend on the geographic positioning (and movement) of the UEs. In some circumstances, the source eNB 604 may indicate the old MSI of the target eNB 606 at the start of the handover procedure. This is to say that the UE 602 may complete handover before the MSI changes at the target eNB 606. The UE 602 may thus be able to successfully decode a given eMBMS service using the old MSI information. Alternatively, the source eNB 604 may indicate a new-MSI of the target eNB 606 and the timing information when a new MSI is applicable. The UE 602 may start handover when the old MSI of the target eNB 606 is valid but complete handover at a time in which the new MSI is applicable at the target eNB 606. Therefore, the UE 602 may thus be able to successfully decode a given eMBMS service using the new MSI information. In some situations however, the UE 602 may not know the MSI of the target eNB 606 after handover has been completed prior to the initiation of the handover procedure. Since the MSI information is not valid after handover, the UE 602 may be unable to decode eMBMS service.

[0086] In deference to this issue, unlike the embodiment of FIG. 5, the

RRCConnectionReconfiguration message 614 may also include the MSI and MSI validity timing information. Specifically, the

RRCConnectionReconfiguration message 614 may include both the current MSI and the new MSI with timing information of validity of each MSI. After handover is completed, the UE 602 may determine which of the MSIs is valid based on the MSI validity timing information. Thus, as the UE 602 may receive multiple pieces of MSI information at when handover is initiated, when handover is completed, the UE 602 may be able continue to receive eMBMS service based on particular MSI valid at that time.

[0087] However, as above, in some circumstances only the current MSI and timing validity of the current MSI may be known at the start of the handover process. In the event that the new MSI is not known when the RRCConnectionReconfiguration message 614 is transmitted, after handover has completed the UE 602 may examine the MSI and timing validity information and determine that it does not have a valid MSI of the target eNB 606.

[0088] In some embodiments, the UE 602 may simply wait for valid MSI information to be provided by the target eNB 606. However, this may lead to eMBMS service interruptions. Accordingly, in some embodiments, the UE 602 may request the MSI from the target eNB 606 using dedicated signaling (MSI Info Request) 618. Thus, transmission of the MSI Information Request 618 from the UE 602 may be triggered by determination that MSI information obtained by the UE 602 in the RRCConnectionReconfiguration message 614 from the source eNB 604 does not contain currently valid MSI information of the target eNB 606.

[0089] In response to the UE 602 transmitting the MSI Information

Request 618 to the target eNB 608, the target eNB 606 may transmit a response 620 that contains the current MSI information. The response 620, like the request 618, may be sent on dedicated signaling. This may permit the UE 602 to obtain the MSI information more quickly than having to wait until the next MSI update is transmitted, which may be an amount of time that is sufficient to cause eMBMS service interruption and may be perceivable by a user. The transmission of the MSI in the response 620 may thus enable the UE 602 to continue receiving eMBMS service with minimal to no interruption.

[0090] In some embodiments, the UE 602, of course, may decode the

MSI of the target eNB 606 autonomously. However, in this case, the UE 602 may wait for next MSP in which the MSI is transmitted. This may cause an eMBMS outage to occur in the UE 602 until the UE 602 receives that MSI information.

[0091] In some embodiments, the request 618 may be dependent on whether or not the target eNB 606 is able to provide any of the eMBMS services used or desired by the UE 602. For example, in situations in which the target eNB 606 provides eMBMS services but is unable to provide any of the eMBMS services of the UE 602, transmission of the request 618 and/or response 620 may be eliminated, thereby avoiding the signaling overhead involved with the request 618 and response 620. [0092] As in FIG. 5, the target eNB 606 to which the UE 602 has attached may broadcast SIB data and transmit MCCH data. The UE 602 may determine which eMBMS services offered by the target eNB 606 are to be received. As some of the eMBMS services available from the source eNB 604 may not be available from the target eNB 606 and some of the eMBMS services available from the target eNB 606 may not be available from the source eNB 604, the UE 602 may lose existing eMBMS services and/or obtain additional eMBMS services when handover occurs from the source eNB 604 to the target eNB 606. The UE 602, having obtained both the SIB broadcast and MCCH data of the target eNB 606, may subsequently receive the desired MTCH data available from the target eNB 606.

[0093] FIG. 7 illustrates a flowchart of a method of UE handover in accordance with some embodiments. The flowchart may involve a UE, source eNB and target eNB such as those shown in one or more of FIGS. 1-4 and described in reference to FIGS. 1-6. At operation 702 the UE may receive a request from the source eNB for an ongoing-TMGI list in one or more succeeding measurement reports.

[0094] Even if the UE does not receive the request at operation 702, the UE may determine that automatic transmission of the TMGI list is warranted at operation 704. For example, the UE may determine that it receives eMBMS services and thus transmission of the TMGI list to the source eNB is desired.

[0095] After receiving the request for the ongoing-TMGI list at operation

702 or determining that transmission of the TMGI list is desired at operation 704, the UE may receive reference signals from the source eNB. The reference signals may be transmitted periodically or aperiodically, and may be, for example, cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), or Discovery Reference Signals (DRS). The UE, in response to receiving the reference signals may, at operation 706, measure one or more characteristics of the references signals, such as SNR or SINR.

[0096] In response to receiving the request for the ongoing-TMGI list, the UE may transmit the TMGI list to the source eNB at operation 708. The UE may provide the ongoing-TMGI list in a measurement report, such as a CQI report, to the source eNB. The UE may additionally provide the ongoing-TMGI list in dedicated signaling to the source eNB. The TMGI list may include TMGIs of only those eMBMS services currently provided by the source eNB or may additionally include eMBMS services desired by the UE but not able to be supplied by the source eNB.

[0097] After receiving the ongoing-TMGI list in the measurement report and based on the measurements contained therein, the source eNB may determine that handover of the UE to a target eNB is desirable. Accordingly, the source eNB may transmit, and the UE may receive at operation 710, a handover message. The handover message may, for example, be an

RRCConnectionReconfiguration message, and may initiate handover of the UE. The RRCConnectionReconfiguration message may contain eMBMS information of the target eNB. The RRCConnectionReconfiguration message may include SIB2-related eMBMS information. In various embodiments, the

RRCConnectionReconfiguration message may also include SIB- 13 related information and/or MSI and MSI timing information of the target eNB. The eMBMS information may include SF allocations, periods and PMCH-InfoList for each MBSFN areas or may limit the information provided to the UE to the MTCH allocation information of only those eMBMS services in the TMGI list.

[0098] The UE, at operation 712, may wait until handover is complete.

The handover process may be conventional, with messages between network resources, including the source eNB, target eNB, MME and serving gateway, among others.

[0099] Once the UE determines at operation 712 that handover is complete, the UE may at operation 714 determine whether the MSI of the target eNB is valid. The UE may have received this information in the

RRCConnectionReconfiguration message. In particular, the UE may make this determination based on the MSI validity timing information in the

RRCConnectionReconfiguration message.

[00100] If the MSI validity timing information of the source eNB was received in the RRCConnectionReconfiguration message but the MSI validity timing information of the target eNB was not received, or if the MSI validity timing information of the target eNB is indicated as no longer valid, the UE may transmit at operation 716 a request to the target eNB for the MSI of the target eNB. The MSI request may be transmitted over dedicated signaling.

[00101] The target eNB, having received the MSI request, may transmit the MSI. The UE may at operation 718 receive the MSI response containing the requested MSI. The MSI response may also be transmitted over dedicated signaling. If the MSI is not valid, the UE may also wait for the next MSI prior to receiving eMBMS service.

[00102] Once a valid MSI is obtained, the UE may at operation 720 receive the eMBMS service. If the UE has the eMBMS information and the MSI is valid, the UE may be able to continue receiving the eMBMS service (if the target eNB supplies the eMBMS service) with minimal to no interruption.

[00103] If at operation 704, the UE has not received a request for the TMGI list and has not transmitted the TMGI list to the source eNB, at operation 726, the UE and source eNB may use a conventional handover process. This is to say that the RRCConnectionReconfiguration message may be free from any eMBMS information. If the RRCConnectionReconfiguration message does not contain eMBMS information of the target eNB or if the MSI information is invalid and the UE waits for the MSI, there may be some interruption of the eMBMS service when the UE receives the eMBMS service at operation 720.

[00104] After the eMBMS service has been obtained by the UE, or perhaps prior to the next set of MTCH data being supplied, at operation 722 the UE may receive SIB broadcast from the target eNB. The UE, which at a minimum has obtained the unicast and eMBMS timing from the

RRCConnectionReconfiguration message via the SIB2-related eMBMS information, may be able to receive the SIB2 and SIB 13 information. Although the UE 502 has already obtained the SIB2-related eMBMS information and perhaps SIB 13-related eMBMS information from the RRCConnectionReconfiguration message, the UE may receive this information again from the SIB broadcast and update the SIB-related eMBMS information as indicated by the SIB broadcast.

[00105] Moreover, the target eNB may also transmit MCCH data, including MBSFN Area Configuration information to the UE. Again, although the UE may have already obtained the MBSFN Area Configuration information from the SIB 13 -related eMBMS information in the

RRCConnectionReconfiguration message, the UE may receive this information again from the MCCH data transmitted during the configuration subframes and may update this information as indicated.

[00106] Example 1 is an apparatus of user equipment (UE) comprising: a transceiver arranged to communicate with an evolved NodeB (eNB); and processing circuitry arranged to: configure the transceiver to receive from the eNB Evolved Multimedia Broadcast Multicast Services (eMBMS) traffic data of an eMBMS service; configure the transceiver to receive from the eNB eMBMS information of a target eNB in an RRCConnectionReconfiguration message used during handover of the UE from the eNB to the target eNB, the eMBMS information comprising eMBMS subframe allocation of the target eNB; and based on the eMBMS subframe allocation, configure the transceiver to establish the eMBMS service at the target eNB free from an eMBMS interruption when the eMBMS subframe allocation at the target eNB is different from an eMBMS subframe allocation at the eNB.

[00107] In Example 2, the subject matter of Example 1 optionally includes that the eMBMS information comprises at least one of System Information Block 2 (SIB2)-related eMBMS information and Multimedia Broadcast

Multicast Service Single Frequency Network (MBSFN) subframe allocations.

[00108] In Example 3, the subject matter of any one or more of Examples

1-2 optionally include that the RRCConnectionReconfiguration message comprises a complete set of eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB. [00109] In Example 4, the subject matter of Example 3 optionally includes that the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each MBSFN area.

[00110] In Example 5, the subject matter of Example 4 optionally includes that the RRCConnectionReconfiguration message further comprises eMBMS System Information Block 2 (SIB2)-related information comprising a MBSFN sub frame configuration list, eMBMS SIB 13 -related information comprising a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration-related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)-InfoList.

[00111] In Example 6, the subject matter of any one or more of Examples

1-5 optionally include that the handover message comprises an

RRCConnectionReconfiguration message, the RRCConnectionReconfiguration message further comprising eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB, the eMBMS allocations limited to eMBMS allocations associated with eMBMS services received by the UE from the eNB.

[00112] In Example 7, the subject matter of Example 6 optionally includes that the processing circuitry is further arranged to: configure the transceiver to provide to the eNB, prior to receiving the eMBMS information, a Temporary Mobile Group Identity (TMGI) list comprising TMGls of ongoing and interested eMBMS services for the UE.

[00113] In Example 8, the subject matter of Example 7 optionally includes that the processing circuitry is further arranged to: configure the transceiver to provide the TMGI list in a measurement report to the eNB, the measurement report comprising a measurement of reference signals transmitted by the eNB.

[00114] In Example 9, the subject matter of any one or more of Examples 1-8 optionally include that the processing circuitry is further arranged to:

configure the transceiver to receive a request from the eNB for a Temporary Mobile Group Identity (TMGI) list comprising TMGls of ongoing and interested eMBMS services for the UE, in response to receiving the request from the eNB for the TMGl list, configure the transceiver to transmit to the eNB the TMGl list, and in response to transmitting the TMGl list to the eNB, configure the transceiver to receive the RRCConnectionReconfiguration message, the

RRCConnectionReconfiguration message further comprising eMBMS service allocations associated with the TMGIs in the list and free from eMBMS service allocations not associated with TMGIs in the list.

[00115] In Example 10, the subject matter of Example 9 optionally includes that the RRCConnectionReconfiguration message further comprises eMBMS System Information Block 2 (SIB2)-related information comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe configuration list and multicast traffic channel (MTCH) information of MTCHs associated with the TMGIs in the TMGl list, the MTCH information comprising a number of MTCHs and MTCH allocation information for each MTCH.

[00116] In Example 1 1, the subject matter of any one or more of

Examples 1-10 optionally include that the RRCConnectionReconfiguration message further comprises the eMBMS information of the target eNB and free from eMBMS System Information Block 13 (SIB13)-related information and comprising eMBMS SIB2-related information comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe configuration list.

[00117] In Example 12, the subject matter of any one or more of

Examples 1-1 1 optionally include that the RRCConnectionReconfiguration message further comprises: multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid.

[00118] In Example 13, the subject matter of Example 12 optionally includes that the processing circuitry is further arranged to: determine from the validity timing of the MSI of the target eNB that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, and in response to determining that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, configure the transceiver to request on dedicated signaling to the UE the MSI of the target eNB from the target eNB.

[00119] In Example 14, the subject matter of any one or more of Examples 1-13 optionally include that the processing circuitry is further arranged to: establish, based on the eMBMS information, eMBMS service at the target eNB during handover free from an eMBMS interruption when an eMBMS subframe allocation at the target eNB is different from a subframe allocation at the eNB.

[00120] In Example 15, the subject matter of any one or more of

Examples 1-14 optionally include, further comprising: an antenna configured to provide communications between the transceiver and the eNB.

[00121] In Example 16, an apparatus of an evolved NodeB (eNB) comprising: a transceiver configured to communicate with a user equipment (UE); and processing circuitry configured to: configure the transceiver to transmit to the UE Evolved Multimedia Broadcast Multicast Services (eMBMS) traffic data of an eMBMS service; determine that handover of the UE to a target eNB is appropriate; and configure the transceiver to transmit to the UE eMBMS information of the target eNB in a RRCConnectionReconfiguration message initiating handover of the UE from the eNB to the target eNB, the eMBMS information comprising eMBMS System Information Block 2 (SIB2)-related information of the target eNB.

[00122] In Example 17, the subject matter of Example 16 optionally includes that the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area.

[00123] In Example 18, the subject matter of Example 17 optionally includes that the eMBMS System Information Block 2 (SIB2)-related information comprises a MBSFN subframe configuration list, and the

RRCConnectionReconfiguration message further comprises eMBMS SIB 13- related information comprising a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration-related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)-InfoList.

[00124] In Example 19, the subject matter of any one or more of

Examples 16-18 optionally include that the RRCConnectionReconfiguration message further comprises eMBMS allocations in a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) area covered by the target eNB, the eMBMS allocations limited to eMBMS allocations associated with eMBMS services transmitted by the eNB to the UE.

[00125] In Example 20, the subject matter of Example 19 optionally includes that the processing circuitry is further arranged to: configure the transceiver to receive from the UE, prior to transmitting the eMBMS information, a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE, configure the transceiver to transmit reference signals, and configure the transceiver to receive the TMGI list in a measurement report comprising a measurement of the reference signals.

[00126] In Example 21, the subject matter of any one or more of

Examples 16-20 optionally include that the processing circuitry is further arranged to: configure the transceiver to transmit to the UE a request from the eNB for a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested eMBMS services for the UE, in response to transmitting the request from the eNB for the TMGI list, configure the transceiver to receive to the eNB the TMGI list, and in response to receiving the TMGI list to the eNB, configure the transceiver to transmit the RRCConnectionReconfiguration message, the RRCConnectionReconfiguration message further comprising eMBMS service allocations associated with the TMGIs in the list and free from eMBMS service allocations not associated with TMGIs in the list, the eMBMS SIB2-related information comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subframe configuration list and multicast traffic channel (MTCH) information of MTCHs associated with the TMGIs in the TMGI list, the MTCH information comprising a number of MTCHs and MTCH allocation information for each MTCH. [00127] In Example 22, the subject matter of any one or more of

Examples 16-21 optionally include that the RRCConnectionReconfiguration message further comprises: multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid.

[00128] Example 23 is a computer-readable storage medium that stores instructions for execution by one or more processors of user equipment (UE) to communicate with an evolved NodeB (eNB), the one or more processors to configure the UE to: transmit to the eNB a Temporary Mobile Group Identity (TMGI) list comprising TMGIs of ongoing and interested Evolved Multimedia Broadcast Multicast Services (eMBMS) service for the UE; receive from the eNB a RRCConnectionReconfiguration message used to initiate handover of the UE from the eNB to a target eNB, the RRCConnectionReconfiguration message comprising a Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) subfirame configuration list of the target eNB for at least the eMBMS services identified by the TMGIs; and establish the eMBMS services identified by the TMGIs at the target eNB based on the MBSFN subfirame configuration list.

[00129] In Example 24, the subject matter of Example 23 optionally includes that the RRCConnectionReconfiguration message further comprises a complete set of eMBMS allocations in each MBSFN area, a MBSFN area information list and a MBMS notification configuration, and MSI and MBSFN area configuration-related information for each MBSFN area comprising a number of MBSFN areas and, for each MBSFN area, a common single frequency allocation, common single frequency allocation period, and a physical multicast channel (PMCH)-InfoList.

[00130] In Example 25, the subject matter of any one or more of Examples 23-24 optionally include that the RRCConnectionReconfiguration message further comprises: multicast channel (MCH) scheduling information (MSI) of the eNB and validity timing of the MSI of the eNB indicating a time period over which the MSI of the eNB is valid, and MSI of the target eNB and validity timing of the MSI of the target eNB indicating a time period over which the MSI of the target eNB is valid, and the instructions further configure the UE to: determine from the validity timing of the MSI of the target eNB that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, and in response to determining that the MSI of the target eNB will be invalid when handover of the UE to the target eNB is completed, request on dedicated signaling to the UE the MSI of the target eNB from the target eNB.

[00131] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

[00132] Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [00133] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain- English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[00134] The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.