Wireless Link Efficiency via Virtual Sequence Numbers
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Solution Overview
Problem
IEEE 802.11 wireless networks face inefficiencies due to per-packet acknowledgement requirements and carrier sense multiple access with collision avoidance (CSMA/CA), leading to low transmission efficiency, especially with packet aggregation mechanisms that limit throughput and cannot fully utilize maximum packet slots.
Innovation Solution
Implementing virtual sequence numbers and virtual traffic category identifiers in packet headers, allowing for stateless transmission and aggregation of packets with non-continuous sequence numbers and different traffic categories, enabling full utilization of packet slots and efficient retransmission without the constraints of traditional acknowledgement windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If per-packet acknowledgement and CSMA/CA are used in IEEE 802.11 wireless networks, then reliable data delivery is achieved, but transmission efficiency deteriorates
Solution Approach 1:
The patent merges multiple packets into a single aggregate frame for transmission. Instead of sending individual packets with separate acknowledgements, multiple packets are combined into one frame that carries a block acknowledgement, reducing the number of round-trip exchanges and improving transmission efficiency while maintaining reliability through the block acknowledgement mechanism.
Solution Approach 2:
The aggregate frame structure serves multiple functions simultaneously: it transmits multiple data packets, carries a block acknowledgement for all packets, and enables efficient retransmission. This multi-functional approach consolidates what would otherwise require separate protocol exchanges into a single unified mechanism.
2Productivity
If packet aggregation is implemented to improve throughput, then transmission efficiency improves, but the ability to accommodate retransmitted packets and utilize maximum packet slots deteriorates
Solution Approach 1:
The patent segments the packet sequence into multiple aggregate frames, where each frame contains a specific range of sequence numbers. This segmentation allows the system to manage retransmissions efficiently by identifying which specific packets need retransmission within the aggregate frame structure, while still maintaining high throughput through aggregation.
Solution Approach 2:
The aggregate frame structure is designed to be dynamic in accommodating both new packets and retransmitted packets. The frame can adapt its content based on which packets require retransmission, allowing flexible utilization of packet slots while maintaining the aggregation benefit for throughput improvement.
3Device complexity
If traditional acknowledgement windows are used, then packet tracking is simplified, but overhead increases and bandwidth utilization deteriorates
Solution Approach 1:
The patent implements a block acknowledgement mechanism that provides feedback for multiple packets in a single acknowledgement frame. This feedback approach allows the receiver to inform the sender which specific packets within the aggregate were successfully received and which need retransmission, reducing overhead compared to individual acknowledgements while maintaining accurate packet tracking.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3B
AI summary
One embodiment of the present invention provides a system for improving transmission efficiency of a wireless link. During operation, a transmitting station first assembles and transmits a multi-TID aggregate frame (operation 502). The transmitting station then receives a BLOCK ACK from the receiving station (operation 504). Based on the received BLOCK ACK, the transmitting station updates its record of per-TID packet error rate (operation 506). The transmitting station then determines, for each TID, whether the packet error rate is greater than a threshold for that TID (operation 508). If so, the transmitting station reserves a number of packet slots in the aggregate frame for duplicate packets of that TID (operation 510) prior to resuming transmission (operation 512). If the per-TID packet error rate is below the threshold, the transmitting station resumes transmission (operation 512). The process repeats itself by looping back to operation 502.