1. Field of the Disclosure
The present disclosure relates to Long Term Evolution (LTE) based communication networks, and more particularly, to Multicast Broadcast Single Frequency Network (MBSFN) data in LTE based communication networks.
2. Description of the Related Art
MBSFN is a technique for providing content to users of a telecommunication network (which uses LTE, LTE Advanced or any other LTE based technology) for providing data to a User Equipment (UE) connected to the network, wherein the data can relate to television content and so on. LTE defines the use of two logical channels for use by MBSFN—a Multicast Control Channel (MCCH) and a Multicast Traffic Channel (MTCH). MCCH is used to transfer control information. MCCH carries a single message, the MBSFNAreaConfiguration message, which indicates the Multimedia Broadcast Multicast Service (MBMS) sessions that are ongoing as well as the corresponding radio resource configuration. MTCH is used to transfer MBMS data packets. User services that include streaming and downloading application services are mapped onto the MTCH. Both of these logical channels can be mapped to a single transport channel meant for multicast/broadcast traffic—Multicast Channel (MCH). MCH is further mapped to an MBSFN specific physical channel termed a Physical Multicast Channel (PMCH).
Sub-frames, which can be used for broadcast/multicast purposes, are termed MBSFN sub-frames. Information about these sub-frames and radio-frames are communicated using a System Information Block (SIB) Type 2, “MBSFN-sub-frameConfigList.” Only sub-frames 1, 2, 3, 6, 7 and 8 can be used for an MBSFN in networks using Frequency Division Duplexing (FDD). For networks using Time Division Duplexing (TDD), sub-frames 3, 4, 7, 8 and 9 can be used for an MBSFN.
The UE can require additional information to identify the presence of MCCH and configurations required to acquire the same. This information is provided to the UE in a separate system information block dedicated for an MBMS (e.g. SIB-13), which carries information about all the MBSFN areas configured under a radio cell to which the UE is connected. On request from a higher layer, a Radio Resource Control (RRC) acquires an SIB-13 and checks if information related to an area of an MBSFN (in which the UE is interested) is present. If the information is present, the UE can further attempt to acquire MCCH information for that MBSFN area.
The UE should have the ability to support both unicast and MBSFN services efficiently and independently of each other. However, it is still difficult to provide unicast services without affecting MBSFN services and vice versa.
Currently, scheduling information is received in an MCH Scheduling Information (MSI) Protocol Data Unit (PDU) by a Media Access Control (MAC) layer. Since decoding is carried out at the PHYsical (PHY) layer, the MAC layer must decode, parse and segregate relevant scheduling information and pass it to the PHY. As the scheduling information is applicable immediately after the reception of the MSI PDU, there is a delay in the configuration of the PHY with the scheduling information and hence the PHY should be able to perform decoding without the scheduling information being configured.
Also, MCCH information is repeated within a stipulated window of time called a modification period. Further, the MCCH information can be provided (e.g. split) into more than one sub-frame. The UE must interpret successful decoding of an MCCH Service Data Unit (SDU) and avoid decoding across repetitions.
The MAC layer in the UE receives the scheduling information in an MSI PDU. The PDU includes the set of sub-frame information for the duration of the MTCH channels that carry MBSFN services. Since decoding is carried out at the PHY layer, the MAC layer must decode, parse and segregate relevant scheduling information pertaining to interested MTCH channels (e.g. services) and pass it to the PHY layer. The scheduling information is applicable immediately after the reception of the MSI PDU that means first MTCH channel data can be scheduled at the earliest time from the same sub-frame in which the MSI PDU is received. Therefore, configuration delay of the PHY with scheduling information, which certainly takes some finite amount of time, would be delayed.