Virtual Link Aggregation in Wireless LANs
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Solution Overview
Problem
Current link aggregation techniques in wireless communications, such as Wi-Fi networks, suffer from delays in splitting and re-allocating data packets across different links due to link failures, leading to reduced performance and inefficiencies in handling communication failures.
Innovation Solution
The establishment of a virtual communication link that combines multiple physical links, such as a 2.4 GHz and a 5 GHz link, using virtual sequence numbers (VSNs) to manage packet transmission and reordering, allowing seamless routing and retransmission of packets across links, even in the event of failures, through a single virtual packet queue and independent action frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data packets are split and assigned to different sessions over different links, then link aggregation throughput is improved, but delay in re-allocating packets after link failure increases
Solution Approach 1:
The patent implements a feedback mechanism where the receiving device sends block acknowledgment frames that include information about successfully received packets. The transmitting device uses this feedback to identify failed packets and re-allocate them to alternative links, creating a closed-loop system that dynamically adapts to link conditions and minimizes re-allocation delay.
Solution Approach 2:
The patent establishes multiple communication sessions across different links in advance before failure occurs. When a link fails, packets can be immediately re-allocated to pre-established alternative sessions without requiring new session setup, thereby reducing re-allocation delay while maintaining high throughput.
2Reliability
If TCP-level re-routing is used after link failure, then data is eventually re-sent over other links, but substantial delay occurs before re-transmission
Solution Approach 1:
The patent segments the communication protocol into multiple layers with independent failure handling mechanisms. Instead of relying solely on TCP-level re-routing, the MAC layer implements its own packet tracking and re-allocation mechanism using sequence numbers and block acknowledgment frames, enabling faster recovery at the data link layer before TCP intervention is needed.
Solution Approach 2:
The patent introduces an intermediary mechanism at the MAC layer that acts as a mediator between the physical link and TCP protocol. This intermediary tracks packet transmission status using sequence numbers and coordinates re-allocation across multiple links, preventing the need for substantial TCP-level re-routing delays.
3Productivity
If multiple physical links are aggregated into one virtual link, then throughput and reliability are improved, but complexity in managing packet sequence numbers increases
Solution Approach 1:
The patent introduces a virtual link layer as an intermediary that manages multiple physical links. This virtual link maintains a single sequence number counter that increments for each packet transmitted across any link, simplifying sequence number management compared to maintaining separate counters for each physical link while still enabling comprehensive packet tracking.
Solution Approach 2:
The patent creates a universal block acknowledgment mechanism that works across multiple physical links through the virtual link abstraction. The receiving device sends a single block acknowledgment frame that acknowledges packets from any link, and the transmitting device uses this universal feedback to manage re-allocation, reducing the complexity of having link-specific acknowledgment protocols.
Data Source
AI summary
Methods, systems, and devices are described for establishing a virtual communication link including at least a first and second physical link between two devices. A single virtual packet queue of a device may receive one or more data packets to be transmitted via the virtual communication link. The single virtual packet queue may attach a virtual sequence number to each of the one or more data packets and send the one or more data packets to one or more of the first or the second physical link according to the assigned virtual sequence numbers. The one or more packets may then be communicated via the first and/or second physical links according to link specific sequence numbers, such as medium access control (MAC) sequence numbers, assigned to the one or more data packets by the first and/or second physical links.