Unlicensed Backhaul Carrier Selection via Cross-Protocol Sensing
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Solution Overview
Problem
Wireless backhaul systems face challenges in maintaining carrier-grade reliability in unlicensed spectrum bands due to interference from licensed users and other devices, which complicates the deployment of high-quality wireless backhaul networks.
Innovation Solution
The implementation of cross-protocol channel sensing and reservation methods, where physical carrier sensing is combined with virtual carrier sensing to select and reserve carriers for backhaul communication links, ensuring bidirectional communication through time division duplexing or frequency division duplexing, even in the presence of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If unlicensed spectrum bands are used for wireless backhaul, then spectrum availability and deployment flexibility are improved, but channel reliability and QoS are deteriorated due to interference from licensed users and other devices
Solution Approach 1:
The system performs preliminary channel sensing and interference detection before establishing backhaul connections. Base stations scan and identify suitable carriers in unlicensed bands, detect potential interference from licensed users and WLAN devices, and pre-select carriers with acceptable interference levels before actual data transmission begins
Solution Approach 2:
The patent introduces an intermediary interference detection and carrier selection mechanism that mediates between the backhaul traffic and interfering signals. The system acts as a middle layer that senses the environment, evaluates carrier quality, and selects optimal carriers that minimize interference impact while maintaining reliability
2Difficulty of detecting and measuring
If physical carrier sensing is used to detect interference, then interference detection capability is improved, but false detection and missed detection rates increase due to bursty interference patterns
Solution Approach 1:
The system merges multiple detection approaches by combining physical carrier sensing with virtual carrier sensing through reservation frames. Physical sensing detects energy levels while virtual sensing uses protocol-based reservation mechanisms to identify occupied channels, creating a complementary detection system that reduces false and missed detections
Solution Approach 2:
Reservation frames serve as an intermediary mechanism that mediates between interfering devices and backhaul communications. These frames establish a virtual reservation system that allows backhaul traffic to identify and avoid carriers currently being used by other devices, improving detection reliability
Data Source
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AI summary
Backhaul traffic reliability is improved in unlicensed spectrum bands by using cross-protocol channel sensing and reservation. Physical carrier sensing may be employed to scan channel quality of a plurality of carriers of an unlicensed spectrum band and select a carrier for use in a wireless backhaul communications link between a first base station and a second base station based on the scanned channel quality. The described features may further include the first base station transmitting a self-addressed reservation frame on the selected first carrier prior to transmission of backhaul data from the first base station to the second base station over the first carrier.