Hybrid ARQ Retransmission Management With Unified MAC+ Buffering
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Solution Overview
Problem
Current wireless communication systems face complexity and latency issues in reliable packet delivery due to redundant signaling and retransmission processes, particularly in HARQ mechanisms, which degrade spectral efficiency and increase overhead.
Innovation Solution
The introduction of a MAC+ layer that merges RLC functionalities, simplifies retransmission management by removing duplicate buffers and signaling, and uses a single set of sequence numbers for synchronization, along with a retransmission management (RM) process that handles packet retransmissions efficiently, reducing latency and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple retransmission loops are enabled in HARQ process, then reliability of data transmission is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent merges the RLC layer functionalities into the MAC layer, creating a MAC+ layer that consolidates retransmission management. This integration eliminates the need for separate RLC entities and reduces the number of independent retransmission loops, thereby maintaining reliability while reducing device complexity.
Solution Approach 2:
The MAC+ layer is designed to perform multiple functions previously handled by separate layers, including HARQ retransmission and RLC retransmission management. This multi-functionality approach reduces the overall system complexity by having a single layer handle diverse retransmission tasks.
2Reliability
If multiple retransmission loops are enabled in HARQ process, then reliability of data transmission is improved, but signaling overhead increases
Solution Approach 1:
By merging RLC functionalities into MAC, the patent consolidates status reporting mechanisms. The MAC+ layer uses a single status PDU structure to report both HARQ and RLC layer transmission statuses, eliminating duplicate signaling and reducing overall signaling overhead while maintaining comprehensive reliability monitoring.
3Reliability
If duplicate buffers are maintained for retransmission, then reliability of packet delivery is improved, but loss of time increases
Solution Approach 1:
The patent eliminates duplicate retransmission buffers by merging RLC and MAC functionalities. The MAC+ layer maintains a single unified buffer structure that handles both HARQ and RLC retransmission needs, removing the time-consuming process of transferring packets between separate buffers and reducing overall latency.
4Adaptability or versatility
If separate RLC and MAC layers are maintained, then adaptability is improved, but device complexity increases
Solution Approach 1:
The MAC+ layer is designed with multi-functional capabilities that maintain the adaptability benefits of having separate layers. It can handle diverse transmission modes, QoS requirements, and retransmission scenarios previously managed by distinct RLC and MAC entities, while presenting a unified simpler interface to upper layers.
Data Source
AI summary
A method for transmitting a packet from a transmitter to a receiver in a wireless communication system begins by building a packet by a transport format combination (TFC) selection process, and the packet is transmitted from the transmitter to the receiver. If the transmitter receives an indication that the packet was not successfully received at the receiver, the packet is retransmitted via a hybrid automatic repeat request (HARQ) procedure. If the HARQ procedure did not successfully transmit the packet, then the packet is retransmitted via a retransmission management (RM) procedure. If the RM procedure did not successfully transmit the packet, then the packet is discarded by the transmitter.