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  1. 1. eMBMS - the future of Multimedia Broadcasting? By: Isybel Harto
  2. 2. What is eMBMS eMBMS is evolved Multimedia Broadcast and Multicast Services. Why Broadcast? •One to many transmission. •More efficiency and lower cost for common content. •Apps: Live Video/Audio Streaming, Push Media, E-Publication, Application Download, OS Updates.
  3. 3. Support in LTE (E-UTRAN) over Single Frequency Network (MBSFN) 1. 2. 3. Simulcast transmission technique realised by transmission of identical waveforms at the same time from multiple cells. An MBSFN transmission from multiple cells within an MBSFN Area is seen as a single transmission by a UE. MBSFN reception is possible in connected and idle states independent of incoming or outgoing calls
  4. 4. Multimedia Broadcast over Single Frequency Network (MBSFN)
  5. 5. MBMS Are Planning
  6. 6. MBMS service area (1/2) • eNBs transmitting MBSFN are required to be synchronised in time • Overlap between MBSFN areas is supported • One cell can belong to several MBSFN areas (up to 8 MCCHs) • An MBMS capable UE is required to receive the signal of at least one of the MBSFN areas • Reserved cells do not contribute to MBSFN, but are timesynchronised to the cells in the MBSFN area and have restricted power on MBSFN resources in order to limit interference
  7. 7. MBMS service area (2/2) • One cell can be belong to up 8 MBSFN areas and it can serve multiple Service Areas (SA)
  8. 8. MBMS channels • Downlink channels related to MBMS – – – – • • • MCCH MTCH MCH PMCH Multicast Control Channel Multicast Traffic Channel Multicast Channel Physical Multicast Channel Multiplexing of MBMS and unicast is realized in the time domain only MCH is transmitted over MBSFN in specific subrames on physical layer MCH is a downlink only channel (no HARQ, no RLC repetitions) – Higher Layer Forward Error Correction (see TS26.346) • • • A single transport block is used per subframe Different services (MTCHs and MCCH) can be multiplexed The MCS of each MCH is fixed in the MBSFN area and selected by the network
  9. 9. Frame structure for shared carriers • TDM principle – MBSFN is not transmitted in subframes 0, 4, 5 and 9 (FDD) and subframes 0, 1, 2, 5, 6 (TDD) – The subframe ratio available for MBMS ranges from 1/320 to 192/320 – A 10/40ms pattern repeats over {1, 2, 4, 8, 16, 32}radio frames • Single MBSFN subframe contains single cell control part and MBSFN part Single cell transmission Multi-cell transmission
  10. 10. Main characteristics of MBSFN Transmission scheme OFDM Channel bandwidths 1.4, 3, 5, 10, 15, 20 MHz Carrier spacing 15 kHz Guard interval 16.7 us Modulation schemes MIMO scheme Transport block transmission duration QPSK, 16QAM, 64QAM single antenna port 1 ms Number of coded blocks per transport block Variable Typical transmit power The eNodeB (Macro cells) maximum transmit power is left to implementation, but most coexistence analyses assume Macro Tx Powers around 40W (46dBm)
  11. 11. Reference signals • Single antenna port • Close frequency spacing to support larger delay spreads extended cyclic prefix, 15kHz carrier spacing
  12. 12. MBMS overall architecture • BMSC (broadcast multicast service center): provides functions for MBMS user service initiation and delivery • MBMS-GW (MBMS gateway): broadcasts MBMS packets to each eNB transmitting the service on M1 interface • MCE (Multi-cell Coordination Entity): Allocates or not the radio resources used by eNBs in the same MBSFN area Configures MBSFN subframes for MBMS control and data broadcast Ensures that the L2/L3 layers in eNBs are well configured for MBSFN operation Determines the MCS for PMCH
  13. 13. MBMS RAN interfaces • Control plane interfaces – M3, M2 interface are control plane interfaces – M3 between MME and MCE carries MBMS session management signaling – A MCE is connected to all eNBs within the same MBSFN area through M2 interface mainly for MBMS session management signaling and radio configuration signaling • User plane interface – M1 interface is a user plane interface (no uplink data and no control plane) – A MBMS GW is connected to multiple eNBs through M1 interface for data distribution – IP multicast is used to deliver the downlink packets and SYNC protocol is used over the M1 interface to keep the content synchronization
  14. 14. MBMS services and higher layer protocol stack
  15. 15. eMBMS Summary • eMBMS provides an efficient and low-cost solution to deliver common multimedia content – Reaches a high scalable number of subscriber for mass audience events – Effective capacity offloading from unicast • Flexible carrier sharing between LTE unicast and broadcast – Reuse LTE resource for eMBMS when and where needed • eMBMS leverages LTE deployment and ecosystem for mass market adoption – Cost-effective upgrade to LTE network and device • Simulation demonstrated up to 17Mbps eMBMS throughtput with 10MHz LTE carrier – OFDM signal enhances the gain from single frequency network transmission
  16. 16. Thank You !!