PHY Layer HARQ Feedback Resource Allocation in WLAN
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Solution Overview
Problem
Existing wireless local area network (WLAN) systems face challenges in efficiently managing HARQ operations at the PHY level, particularly in reducing feedback resources and minimizing channel IDLE time, while preventing interference from overlapping BSS (OBSS).
Innovation Solution
A method for HARQ operations at the PHY layer in a WLAN system, which involves defining resource allocation for ACK signals and optimizing feedback resources, ensuring that even non-transmitting STAs do not prolong channel IDLE time, and minimizing interference from OBSS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional HARQ operations are used in WLAN systems, then feedback can be transmitted, but feedback resource usage increases and channel IDLE time is prolonged
Solution Approach 1:
The patent merges the HARQ feedback transmission with uplink data transmission by allowing STAs to send ACK/NACK signals together with their uplink data in the same time-frequency resources. This combining approach eliminates the need for separate feedback resources, directly reducing feedback resource usage while maintaining reliable HARQ operations.
Solution Approach 2:
The patent makes uplink resources multi-functional by enabling them to simultaneously carry both uplink data and HARQ feedback signals. This universal resource usage allows the same resources to serve multiple purposes, reducing the total resource consumption while ensuring reliable feedback transmission.
2Reliability
If traditional HARQ operations are used in WLAN systems, then feedback can be transmitted, but channel IDLE time is prolonged for non-transmitting STAs
Solution Approach 1:
The patent requires STAs to send HARQ feedback signals at predetermined timings regardless of whether they have uplink data to transmit. This preliminary action ensures that feedback is transmitted without delay, preventing channel IDLE time from being prolonged while maintaining reliable HARQ operations.
Solution Approach 2:
The patent ensures continuous channel utilization by having all STAs transmit feedback signals at scheduled times, preventing the channel from remaining idle. This continuous action eliminates gaps in channel usage while ensuring that HARQ feedback is reliably transmitted without delay.
3Productivity
If increased bandwidth and enhanced PPDU structure are used in EHT standard, then communication throughput is improved, but resource allocation complexity and interference management become more challenging
Solution Approach 1:
The patent segments the wideband channel into multiple resource units (RUs) and assigns specific RUs for uplink data and HARQ feedback transmission. This segmentation approach simplifies resource allocation in the EHT system by providing a structured method for managing resources, reducing the complexity associated with increased bandwidth and enhanced PPDU structure.
4Reliability
If more feedback resources are allocated, then HARQ reliability is improved, but channel efficiency decreases due to prolonged IDLE time
Solution Approach 1:
The patent combines HARQ feedback transmission with uplink data transmission in the same resources, ensuring that feedback reliability is maintained without requiring additional dedicated feedback resources. This merging approach prevents channel efficiency from decreasing due to prolonged IDLE time, as the same resources are productively utilized for both data and feedback.
Data Source
AI summary
An AP and a STA can perform a PHY-level HARQ operation in a wireless local area network system, and the AP can transmit resource allocation information about a PHY-level feedback frame to be transmitted by a plurality of STAs. The AP can receive a plurality of HARQ feedback frames from a plurality of STAs. The plurality of HARQ feedback frames are PHY layer signals. The resource allocation information can include information related to a tone set and a symbol from which transmission of the plurality of HARQ feedback frames are started.