Distributed Prioritized Spectrum Contention Protocol

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Solution Overview

Problem

Existing spectrum sharing protocols, such as the IEEE 802.22 on-demand contention protocol, face inefficiencies including high collision probability, excessive contention frames, and poor scalability due to random back-off windows and transmission order, leading to suboptimal channel access in wireless communication systems.

Innovation Solution

A distributed prioritized contention protocol where contenders monitor the channel and adjust their back-off values based on their generated contention numbers, allowing higher-priority devices to transmit first, thereby reducing the number of contention frames and collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If random back-off windows are used in spectrum contention protocols, then all contenders have equal opportunity to access the channel, but collision probability increases and the number of contention frames increases

Engineering Contradiction:

Improveequal access opportunityVSAvoidcollision probability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the back-off window size parameter based on the contention number. Contenders with higher priority (higher contention numbers) use smaller back-off windows, while lower priority contenders use larger back-off windows. This dynamic parameter adjustment reduces collisions by staggering transmission attempts while maintaining fair access opportunities for all contenders.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If random back-off windows are used in spectrum contention protocols, then all contenders have equal opportunity to access the channel, but the number of contention frames increases

Engineering Contradiction:

Improveequal access opportunityVSAvoidnumber of contention frames

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent dynamically adjusts the back-off window size parameter based on contention priority. High-priority contenders use smaller back-off windows to transmit their contention numbers earlier, reducing the total number of contention frames needed. Low-priority contenders use larger back-off windows to avoid collisions and wait for their turn, thereby reducing overall channel access time while maintaining equal access opportunities.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If fixed back-off windows are used in spectrum contention protocols, then the protocol is simple to implement, but scalability is poor when many contenders compete for the channel

Engineering Contradiction:

Improveprotocol implementation complexityVSAvoidscalability

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent implements a scalable back-off mechanism where the window size parameter is dynamically adjusted based on the contender's priority level (contention number). This maintains relatively simple implementation while significantly improving scalability, as the adaptive parameter adjustment allows the protocol to efficiently handle varying numbers of contenders without requiring complex coordination mechanisms.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8675623B2Distributed prioritized contention for spectrum sharing

Publication Date: 2014.03.18 QUALCOMM INC

AI summary

Techniques for use in contending for a portion of a television channel spectrum are disclosed. In some instances, a back-off value is used to decide whether a contender's contention number will be transmitted when the contention channel is free, and the back-off value is determined based on the contention number. In some instances, a contender monitors the contention channel and withdraws from contention if it detects from the contention channel that a higher priority contender is in contention.