Wireless Packet Retransmission via Queuing and Merging

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Solution Overview

Problem

Existing wireless link protocols, such as IEEE 802.11e, may fail to successfully retransmit data packets due to temporary interference, leading to inefficient retry attempts and reduced network utilization, as they rely on random backoff procedures that may not adequately address persistent interference.

Innovation Solution

Introducing a delay before retransmitting a lost data packet until a second packet is received, allowing for increased probability of interference termination and optimizing packet transmission by sending both packets together within a single transmit opportunity or encapsulating them in a single frame, thereby improving network efficiency and reducing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If immediate retransmission is performed after packet loss, then retransmission speed is maintained, but interference may cause repeated transmission failures

Engineering Contradiction:

Improveretransmission speedVSAvoidtransmission success rate

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by introducing a delay period before retransmission, allowing the wireless medium to clear temporary interference before attempting to resend the lost packet. This preemptive waiting period increases the likelihood of successful retransmission by avoiding immediate retransmission into persistent interference conditions.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple retry attempts are made with backoff procedure, then transmission reliability improves, but network utilization decreases

Engineering Contradiction:

Improvetransmission success rateVSAvoidnetwork utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple transmission opportunities by combining the retransmission of lost packets with the transmission of newly received packets. This consolidation allows the transmitting device to utilize the wireless medium more efficiently by sending multiple packets in a single transmission opportunity, thereby improving network utilization while maintaining reliability.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If random backoff procedure is used for retransmission, then collision avoidance is achieved, but latency increases

Engineering Contradiction:

Improvecollision avoidanceVSAvoidpacket transmission latency

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent changes the backoff parameter from a random extended period to a fixed, shorter delay period. This modification reduces the average waiting time before retransmission while still providing sufficient time for interference termination, thereby reducing latency while maintaining collision avoidance capabilities.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8072910B2Retransmitting lost packet with subsequent received packet

Publication Date: 2011.12.06 CISCO TECHNOLOGY INC

AI summary

In one embodiment, a method comprises transmitting onto a wireless connection, by a device, a first wireless data packet destined for a second device; in response to a determined absence by the device of a required acknowledgment of the first wireless data packet from the second device, queuing by the device the first wireless data packet while waiting for a second wireless data packet; receiving by the device the second wireless data packet; and transmitting, by the device, the first wireless data packet with the second wireless data packet to the second device via the wireless connection in response to the device receiving the second wireless data packet and before any other device can send a data frame on the wireless connection.