FDR Wireless LAN PPDU Transmission with Resource Unit Segmentation
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Solution Overview
Problem
Current WLAN systems face challenges in improving spectrum efficiency and area throughput, especially in dense environments with multiple access points and stations, and in outdoor settings, where self-interference is a significant obstacle for Full-Duplex Radio (FDR) operations.
Innovation Solution
The proposed method involves transmitting and receiving PPDU based on FDR in a WLAN system, using newly defined fields like FDR-SIG-C, and reusing HE PPDUs and fields to ensure backward compatibility with 802.11ax, allowing for symmetric and asymmetric FDR operations by allocating different resource units for downlink and uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If FDR operation is implemented in WLAN system, then spectrum efficiency and area throughput are improved, but self-interference occurs between simultaneous downlink and uplink transmissions
Solution Approach 1:
The patent segments the frequency spectrum into different resource units (RUs) for downlink and uplink transmissions. By allocating specific frequency subbands to different directions (DL/UL), the system enables simultaneous full-duplex operation while reducing self-interference through frequency separation. This is achieved by dividing the total bandwidth into multiple RUs and assigning them to different transmission directions.
Solution Approach 2:
The patent applies different transmission qualities and power levels to different resource units based on their direction (downlink or uplink). By adjusting local transmission parameters such as power control and modulation schemes for each RU, the system optimizes performance while managing self-interference locally in specific frequency regions.
2Productivity
If FDR operation is implemented in WLAN system, then area throughput is improved, but device complexity increases due to self-interference management
Solution Approach 1:
The patent divides the system into separate downlink and uplink resource unit sets, allowing independent management of each direction. This segmentation simplifies the complexity of full-duplex management by treating DL and UL as separate entities with dedicated resource allocation, rather than managing them as a single complex integrated system.
Solution Approach 2:
The patent performs preliminary resource allocation and direction assignment before actual transmission. By pre-configuring which RUs are designated for downlink and which for uplink, and by establishing power control parameters in advance, the system reduces the complexity of real-time self-interference management during active transmission.
3Adaptability or versatility
If new FDR-specific fields are added to PPDU structure, then FDR operation capability is enhanced, but overhead increases
Solution Approach 1:
The patent merges FDR-specific information with existing HE PPDU structures. By integrating direction indication, resource unit allocation, and other FDR parameters into the existing HE-SIG-A and HE-SIG-B fields, the patent avoids creating entirely separate signaling structures, thereby reducing overhead while maintaining full FDR capability.
Solution Approach 2:
The patent designs the FDR signal fields to serve multiple functions simultaneously. For example, the resource unit allocation fields not only indicate which RUs are assigned but also implicitly convey direction information. This multi-functionality reduces the need for separate dedicated fields, thereby reducing overall overhead.
4Ease of operation
If resource units are allocated for both downlink and uplink in FDR mode, then simultaneous bidirectional communication is enabled, but interference management becomes more difficult
Solution Approach 1:
The patent segments the resource units into distinct downlink and uplink sets with clear boundaries. By creating separate RU pools for each direction and assigning them non-overlapping frequency resources, the system enables easy bidirectional communication while simplifying interference management through clear spatial and spectral separation.
Solution Approach 2:
The patent introduces direction indication fields and resource allocation mechanisms as intermediaries that coordinate between downlink and uplink transmissions. These intermediary signaling elements manage the interaction between simultaneous DL and UL operations, resolving potential conflicts and simplifying interference management through structured coordination.
Data Source
AI summary
Disclosed is a method and a device for transmitting and receiving a PPDU based on FDR in a wireless LAN system. More specifically, an AP generates FDR indication information on that the AP is capable of performing the FDR and transmits a DL PPDU including the FDR indication information to a first STA and a second STA. The AP receives a first UL PPDU from the first STA and a second UL PPDU form the second STA. A DL PPDU, a first UL PPDU, and a second UL PPDU are transmitted and received based on the FDR.