WLAN Frame Aggregation with Per-PHDU CRC for Selective HARQ
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Solution Overview
Problem
Current wireless local area network (WLAN) standards face inefficiencies in frame transmission and retransmission due to the lack of individual encoding/decoding and cyclic redundancy check (CRC) application at the physical layer, which affects the hybrid automatic repeat request (HARQ) process.
Innovation Solution
A method and apparatus for transmitting and receiving frames in a WLAN that involves aggregating physical-layer HARQ data units (PHDUs) with individual CRCs, allowing for accurate decoding and retransmission of specific PHDUs based on ACK/NACK information, using a PHY header that includes information about each PHDU such as HARQ process identifiers and incremental redundancy details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual encoding/decoding and CRC application are applied to each PHDU, then data reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the aggregated PHDU into individual PHDUs, each with its own encoding/decoding and CRC application. This segmentation allows independent error detection and correction for each unit, improving data reliability while managing complexity through modular processing of smaller, standardized units.
2Measurement precision
If individual CRC is provided for each PHDU, then measurement precision is improved, but loss of time increases due to additional processing
Solution Approach 1:
The patent applies CRC checks individually to each PHDU during the initial decoding process, allowing early detection of errors before full aggregation processing. This preliminary action prevents wasted processing time on corrupted data and enables selective retransmission of only affected PHDUs.
3Productivity
If NACK transmission for specific PHDUs is implemented, then productivity is improved through selective retransmission, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the receiving device transmits NACK signals for specific PHDUs that failed decoding. This feedback enables the transmitting device to perform selective retransmission of only the problematic PHDUs, improving overall productivity by avoiding redundant retransmission of successfully received data.
Data Source
AI summary
A method for transmitting or receiving a frame by a STA in a WLAN according to one embodiment of the present invention may comprise the steps of: receiving a first frame including a PHY header and an A-PHDU obtained by aggregating PHDUs which are PHY data transmission units for a HARQ process; decoding at least one PHDU for the STA in the A-PHDU on the basis of the PHY header; and transmitting a second frame including ACK/NACK information on each of the at least one PHDU for the STA, according to a decoding result, wherein a CRC is individually provided to each of the PHDUs included in the A-PHDU, and the STA transmits a NACK through the second frame in relation to a particular PHDU for which a CRC failure has occurred during the decoding of the particular PHDU.