MPDU Forwarding in VBSS Mesh Networks
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Solution Overview
Problem
In mesh networks, the existing MSDU forwarding mechanism faces issues such as link throughput drops due to Block Ack jitter and data loss during roaming, where MPDUs are fragmented, leading to discarding of subsequent packets and loss of data integrity.
Innovation Solution
The proposed solution involves de-aggregating AMPDUs into MPDUs at the extender AP, processing them based on address information to convert MAC headers between backhaul and fronthaul, avoiding decryption and encryption, and re-aggregating for efficient forwarding, thus eliminating interference and maintaining sequence numbers for seamless roaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MSDU forwarding mechanism is used to forward traffic between STA and root AP through extender AP, then data can be transmitted through the mesh network, but link throughput drops due to Block Ack jitter and data loss during roaming
Solution Approach 1:
The patent segments the forwarding process into two distinct modes: MSDU forwarding (protocol stack parsing and reassembly) and MPDU forwarding (direct header switching). This segmentation allows selective use of the more efficient MPDU mode for stable connections while maintaining MSDU mode for roaming scenarios, thus improving overall link throughput without sacrificing data integrity
Solution Approach 2:
The patent introduces dynamic switching between MSDU forwarding and MPDU forwarding modes based on connection stability and roaming detection. The system can transition from static MSDU forwarding to dynamic mode selection, adapting to network conditions to prevent Block Ack jitter and maintain reliable data transmission
2Adaptability or versatility
If MPDUs are fragmented during roaming, then data can be forwarded through different APs, but subsequent packets are discarded leading to data loss
Solution Approach 1:
The patent performs preliminary actions by maintaining sequence numbers and packet counters before roaming occurs. When roaming is detected, the system uses pre-maintained state information to properly reassemble fragmented MPDUs at the destination AP, preventing packet discarding and ensuring data integrity during handover
Solution Approach 2:
The patent implements feedback mechanisms where receiving APs monitor sequence numbers and packet continuity. When fragmentation or gaps are detected during roaming, the system uses feedback information to request retransmission or properly handle fragmented packets, thereby maintaining data integrity while enabling seamless roaming
3Productivity
If MAC header switching is performed to convert between backhaul and fronthaul headers, then forwarding efficiency is improved, but decryption and encryption operations are required increasing complexity
Solution Approach 1:
The patent extracts the decryption and encryption operations from the mandatory header switching process. By using encrypted MPDU forwarding where the encrypted payload is treated as opaque data, the system performs header switching without requiring decryption, thereby maintaining high forwarding efficiency while reducing processing complexity
Data Source
AI summary
Embodiments of the present disclosure relate to device, method, apparatus and computer readable storage medium of MPDU forwarding in a VBSS based mesh network. The method comprises receiving, at a first device, a first data unit from a second device in a first TXOP allocated by the second device for data transmission between the first device and the second device, the first data unit having a header comprising an identifier of the first device; de-aggregating the first data unit into a plurality of sub-data units; and processing the plurality of sub-data units based on respective address information associated with the plurality of sub-data units. In this way, the converting the MAC header of MPDUs between backhaul and fronthaul and decryption and encryption of the data unit can be avoided, which improves the efficiency of data forwarding. Meanwhile, the interference between backhaul and fronthaul working on the same channel can be eliminated and the TP of whole link can be increased.