Wireless Device Carrier Sensing for Unlicensed Band Interference Mitigation
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Solution Overview
Problem
In wireless communication systems, especially in unlicensed bands where various communication protocols coexist, beam-forming can lead to unexpected interference despite carrier sensing, making it difficult to predict and mitigate interference between devices.
Innovation Solution
A method where a wireless device performs carrier sensing for a receive beam direction acquired from a request signal and transmits a response signal only if the wireless medium is idle, allowing for controlled initiation of downlink transmission and mitigating interference by adjusting beam directions and channel access strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If beam-forming is supported in the unlicensed band, then coverage is increased, but unexpected interference occurs even after carrier sensing
Solution Approach 1:
The wireless device performs carrier sensing in advance before transmitting the response signal to determine if the channel is idle. This preliminary channel assessment prevents transmissions that would cause interference, allowing beam-forming to extend coverage while maintaining interference avoidance through proactive channel state verification
Solution Approach 2:
The base station transmits a request signal that includes information about the transmit beam direction, and the wireless device provides feedback by transmitting a response signal only after confirming the channel is idle through carrier sensing. This feedback mechanism ensures that beam-forming operations coordinate channel availability information, preventing interference while maintaining extended coverage
2Ease of operation
If carrier sensing is performed before transmission, then channel access is controlled, but interference cannot be fully predicted in beam-forming scenarios
Solution Approach 1:
The carrier sensing operation is specifically tailored to the receive beam direction indicated in the request signal. Instead of generic omnidirectional sensing, the wireless device performs localized channel assessment in the specific spatial direction where transmission will occur, providing both operational control and reliable interference prediction for beam-forming scenarios
Solution Approach 2:
The wireless device performs carrier sensing in advance before transmitting the response signal to determine if the channel is idle. This preliminary channel assessment in the specific receive beam direction enables reliable interference prediction by verifying channel availability in the exact spatial direction where beam-forming transmission will occur
3Productivity
If various communication protocols coexist in the unlicensed band, then spectrum utilization is improved, but interference between protocols increases
Solution Approach 1:
The carrier sensing operation acts as an intermediary mechanism between different communication protocols sharing the unlicensed band. By verifying channel availability before transmission in the specific receive beam direction, it mediates access between coexisting protocols, enabling improved spectrum utilization while preventing interference through coordinated channel state verification
Data Source
AI summary
A wireless device in an unlicensed band receives from a base station a request signal requesting initiation of downlink (DL) transmission. If carrier sensing (CS) is performed and a wireless medium idles, the wireless device transmits to the base station a response signal accepting the initiation of the DL transmission. The CS is performed with respect to a receive (RX) beam direction obtained from the request signal.