FDR Signal Fields for WLAN Throughput and Self-Interference
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Solution Overview
Problem
Next-generation wireless local area networks (WLANs) face challenges in improving spectrum efficiency and area throughput, especially in dense environments with multiple access points and stations, and in outdoor settings, where existing technologies struggle with interference and performance optimization.
Innovation Solution
The proposal involves a method and apparatus for transmitting physical layer protocol data units (PPDUs) using full duplex radio (FDR) in WLAN systems, which includes defining new fields such as FDR-SIG-C and reusing existing HE PPDU fields to enable backward compatibility, while minimizing self-interference and overhead, allowing simultaneous downlink and uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex radio (FDR) is implemented to enable simultaneous downlink and uplink transmissions, then throughput is improved, but self-interference occurs
Solution Approach 1:
The patent segments the frequency spectrum into multiple resource units (RUs), allowing downlink and uplink transmissions to occur simultaneously in different frequency segments. This frequency division enables FDR operation by separating the transmit and receive paths in the frequency domain, thereby improving throughput while avoiding self-interference through spectral isolation.
2Adaptability or versatility
If new fields such as FDR-SIG-C are defined to enable FDR operation, then system functionality is improved, but device complexity increases
Solution Approach 1:
The patent defines new signal fields (FDR-SIG-A, FDR-SIG-B, FDR-SIG-C) that serve multiple functions: indicating FDR operation mode, specifying resource unit allocations for both downlink and uplink, and providing backward compatibility indicators. These multi-functional fields enable the system to support both traditional half-duplex and new full-duplex operations without requiring completely separate signaling mechanisms, thus improving functionality while managing complexity.
Solution Approach 2:
The patent incorporates FDR indication information and resource allocation details in advance within the signal fields before actual data transmission begins. This preliminary signaling allows receiving devices to prepare appropriate processing modes and resource mappings ahead of time, reducing real-time processing complexity while enabling sophisticated FDR functionality.
3Productivity
If resource units are allocated for both downlink and uplink in FDR mode, then spectrum efficiency is improved, but overhead increases
Solution Approach 1:
The patent merges the downlink and uplink resource allocation information into a unified signal field structure (FDR-SIG-A and FDR-SIG-B) that simultaneously conveys both directions' resource unit assignments. By combining what would traditionally be separate signaling sequences into integrated fields, the patent reduces redundant overhead while maintaining comprehensive resource allocation capability for bidirectional FDR transmission.
Data Source
AI summary
A method and an apparatus for transmitting and receiving PPDU on the basis of FDR in a wireless LAN system are presented. Specifically, an AP generates FDR indication information that FDR can be performed. The AP transmits a DL PPDU including the FDR indication information to a first STA. The AP receives a UL PPDU from the first STA. The DL PPDU includes a legacy signal field, a first signal field, a second signal field, a third signal field, and a DL data field. The second signal field includes information on an RU placement in the entire frequency band and allocation information for a first RU to which the DL data field is allocated. The third signal field includes allocation information for a second RU to which the UL PPDU is allocated on the basis of the information on the RU placement. The allocation information for the second RU includes a bitmap of whether the UL PPDU is allocated in units of 26 RUs.