WRAN Channel Switching via Random Delay Circuit

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Solution Overview

Problem

Wireless Regional Area Networks (WRAN) face challenges in avoiding channel collisions during channel switching, which can lead to interference with licensed incumbent services and degrade the quality of service.

Innovation Solution

The implementation of a method and apparatus that uses a cognitive radio system with a spectrum manager and random delay circuit to dynamically select and switch channels, avoiding collisions by generating a random delay time for channel switching, thereby minimizing the likelihood of multiple WRAN stations selecting the same channel simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If WRAN stations switch channels dynamically to avoid incumbent interference and maintain QoS, then service reliability is improved, but channel collisions between WRAN stations increase

Engineering Contradiction:

Improveservice reliabilityVSAvoidchannel collisions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary sensing of the target channel before switching occurs. By detecting incumbent presence and WRAN station activity in advance, the system avoids switching to occupied channels, thereby preventing collisions while maintaining reliable service.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The channel switching mechanism incorporates feedback from spectrum sensing results. Stations continuously monitor channel occupancy and adjust their switching decisions based on real-time feedback about incumbent presence and other WRAN activities, dynamically avoiding collisions.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If WRAN stations use frequency hopping to distribute communication over multiple frequencies, then interference with incumbents is reduced, but channel switching complexity increases

Engineering Contradiction:

Improveinterference with incumbentsVSAvoidchannel switching complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The frequency hopping mechanism employs periodic channel switching according to a predetermined pattern. Stations hop through multiple frequencies at regular intervals, distributing their communication over time and frequency while following a structured sequence that manages complexity.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts frequency hopping parameters such as hop rate, sequence, and target channel selection based on sensed environmental conditions. This allows the system to adapt to changing incumbent patterns and WRAN traffic requirements while maintaining manageable complexity through standardized protocols.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8588115B2Apparatus for controlling channel switching in wireless networks

Publication Date: 2013.11.19 THOMSON LICENSING SA

AI summary

The invention provides apparatus methods for avoiding channel collisions in Wireless Regional Area Networks (WRAN), A medium access controller (MAC) for switching a base station (BS) of a WRAN from a first channel to a second channel at a time t is provided. The MAC includes a switch time delay circuit for delaying said switching with respect to time t by a random delay time.