MAC PDU Sharing for Multicast Resource Efficiency
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Solution Overview
Problem
In LTE systems, unicast MAC transport blocks are UE-specific, leading to inefficient use of resources when broadcasting or multicasting content to multiple users, as existing technologies do not effectively manage shared radio resources and acknowledgement modes for multicast services, resulting in waste of processing power and limited MBSFN resources.
Innovation Solution
Implementing a system and method for media access control transport block sharing among multiple user equipments, where a communications controller determines and transmits MAC PDUs destined for multiple UEs, using group-specific RNTIs and MAC sub-headers to indicate intended recipients, allowing UEs to parse and provide feedback on shared data, and dynamically manage retransmissions based on HARQ and RLC feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unicast MAC transport blocks are used for each UE, then each UE can receive dedicated data, but radio resources are wasted when broadcasting to multiple users
Solution Approach 1:
The patent merges multiple UE-specific MAC PDUs into a single shared MAC PDU that can be received by multiple UEs simultaneously. This is achieved by introducing a group identifier field and multiple payload fields in the MAC PDU structure, allowing one transmission to serve multiple destinations, thereby improving resource efficiency while managing complexity through standardized formatting.
Solution Approach 2:
The MAC PDU structure is designed to be universal, serving both traditional unicast functions and new multicast/broadcast functions. The inclusion of a group identifier field allows the same MAC PDU format to accommodate both dedicated UE communications and group-based transmissions, enabling multi-functionality without requiring separate protocol structures.
2Adaptability or versatility
If traditional unicast signaling is used for multicast services, then existing protocols can be maintained, but processing power is wasted and MBSFN resources are limited
Solution Approach 1:
The patent segments the MAC PDU into distinct fields including a group identifier field and multiple payload fields. This segmentation allows the receiving UEs to efficiently identify whether the transmission is intended for them using the group identifier, reducing unnecessary processing power consumption compared to traditional unicast signaling where each UE would process the entire signaling structure regardless of relevance.
3Productivity
If MAC PDUs are shared among multiple UEs, then resource efficiency improves, but feedback management becomes more complex
Solution Approach 1:
The patent implements a feedback mechanism where UEs send acknowledgments or negative acknowledgments for received MAC PDUs. The communications controller uses this feedback to determine whether retransmission is necessary, managing the complexity of shared PDU feedback through systematic acknowledgment collection and decision-making based on the feedback received from multiple UEs.
Data Source
AI summary
In one embodiment, a method for transmitting a first media access control (MAC) protocol data unit (PDU) includes determining a plurality of user equipments (UEs) in a group of UEs and determining that a first MAC PDU is destined for multiple UEs in the group of UEs. The method also includes setting the first MAC PDU to indicate that the first MAC PDU is destined for multiple UEs in the group of UEs and transmitting, by a communications controller to the plurality of UEs, the first MAC PDU.