TCP Proxy RTT Analysis for Wireless Congestion Detection

The patent introduces a proxy device as an intermediary between the TCP sender and receiver. The proxy intercepts TCP packets, calculates RTT values, and determines whether packet loss is due to congestion or wireless errors. By acting as a mediator, the proxy prevents TCP's AIMD/Slow Start mechanisms from unnecessarily reducing transmission rates during non-congestion packet loss events, thereby maintaining high network utilization while still handling packet loss reliably.

The patent implements a feedback mechanism where the proxy continuously monitors RTT values and compares them against thresholds to determine the cause of packet loss. When packet loss is detected, the proxy uses RTT feedback to distinguish between congestion-induced loss (where rate reduction is appropriate) and wireless error-induced loss (where rate reduction should be avoided). This feedback loop enables the system to maintain high wireless link efficiency while still mitigating packet loss appropriately.

The patent employs self-service principles by using existing TCP feedback packets (ACKs) to carry timing information for RTT calculation. The proxy leverages the natural bidirectional communication already present in TCP to obtain measurement data without requiring additional dedicated probe packets or complex external measurement infrastructure. This approach achieves precise congestion state determination while minimizing the increase in system complexity.