MBMS Logical Channel Identification via MAC Header
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Solution Overview
Problem
In LTE MBMS, User Equipment (UE) struggles to accurately identify the type of logical channels when multiple MBMS logical channels are multiplexed on a MAC PDU, leading to abnormal operations and practical inconvenience.
Innovation Solution
The method involves an evolved Node B (eNB) notifying the UE of a radio frame or subframe carrying an MBMS Control Channel (MCCH) through a system broadcast message, allowing the UE to read the MAC head and identify the logical channel type using either an MBMS service identifier or a Logical Channel Identifier (LCID), thereby determining the correct location of data within the MAC Service Data Unit (SDU).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple MBMS logical channels are multiplexed on a MAC PDU without identifier transmission, then resource utilization is improved, but the UE cannot accurately identify logical channel types
Solution Approach 1:
The patent introduces an intermediary element (identifier field) within the MAC PDU structure that mediates between the multiplexed logical channels and the UE. This identifier acts as a mediator that carries channel type information without requiring separate signaling messages, thus maintaining resource efficiency while enabling accurate channel identification.
Solution Approach 2:
The MAC PDU is segmented into distinct components including a MAC header with identifier fields and payload sections. This segmentation allows the UE to parse and identify different logical channel types (MCCH, MTCH) within the multiplexed structure by examining the identifier segments, resolving the contradiction between multiplexing efficiency and identification accuracy.
2Measurement precision
If logical channel identifiers are added to MAC PDU structure, then UE can accurately identify channel types, but system complexity increases
Solution Approach 1:
The patent merges the identifier information directly into the existing MAC PDU structure by utilizing and extending current header fields. Rather than adding completely separate identifier messages or structures, the solution combines identification functionality with the existing MAC layer protocol structure, reducing overall system complexity while maintaining identification accuracy.
Solution Approach 2:
The MAC header structure is designed to serve multiple functions: it simultaneously provides channel identification, data length information, and protocol control. This multi-functionality reduces the need for separate dedicated identifier structures, thereby limiting the increase in system complexity while achieving accurate logical channel identification.
3Measurement precision
If MBMS service identifier is used in MAC head, then channel identification is enabled, but information overhead increases
Solution Approach 1:
The patent utilizes parameter changes by assigning specific numerical values to the MBMS service identifier field to represent different logical channel types (e.g., specific values for MCCH versus MTCH). This allows compact binary encoding of channel type information, minimizing the bit overhead while enabling accurate identification through simple parameter comparison at the UE side.
Data Source
AI summary
The present invention discloses a method for transmitting a logical channel identifier in a Multimedia Broadcast Multicast Service (MBMS), it comprises: an evolved Node B (eNB) notifies a User Equipment (UE) of a radio frame or a radio subframe carrying an MBMS Control Channel (MCCH) through a system broadcast message; and the UE reads a Medium Access Control (MAC) head from the radio frame or radio subframe, identifies the type of a logical channel according to the MAC head, and reads data from an MAC Service Data Unit (SDU). The present invention also discloses a system for transmitting a logical channel identifier in an MBMS. By adopting the present invention, the UE can accurately identify the type of the logical channel when various types of MBMS logical channels multiplex on the same MAC Protocol Data Unit (PDU).