Wireless Channel Access Parameter Configuration for Unlicensed Spectrum
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Solution Overview
Problem
Current wireless communication systems in unlicensed bands face challenges in ensuring fair coexistence and high reliability due to varying channel access procedures, particularly in environments where legacy mechanisms are not suitable for higher frequencies with beam-forming features.
Innovation Solution
The proposed solution involves configuring user equipment (UE) and base stations with specific parameters that indicate the application of channel access procedures for transmissions, allowing for adaptive channel access based on system information and RRC messages, which can include indications for beam-forming, to ensure reliable communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy channel access procedures are used in unlicensed bands, then fair coexistence is ensured, but communication reliability deteriorates in high-frequency bands with beam-forming
Solution Approach 1:
The patent implements dynamic channel access procedures where the gNB configures different LBT parameters (such as contention window sizes, defer periods, and channel access priorities) based on the specific frequency band, beam-forming configuration, and traffic type. This allows the system to adapt channel access behavior dynamically rather than using fixed legacy procedures, resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The patent changes multiple parameters of the channel access procedure including contention window minimum and maximum values, defer period durations, channel access priority indices, and beam-specific LBT parameters. These parameter changes enable the system to optimize channel access for different frequency bands and beam-forming scenarios while maintaining fair coexistence in unlicensed spectrum.
2Productivity
If channel access procedure is applied for all transmissions, then fair spectrum usage is ensured, but communication performance deteriorates due to unnecessary sensing delays
Solution Approach 1:
The patent segments the channel access procedure application by transmission type, direction, and priority. Different channel access requirements are assigned to different transmission categories (e.g., uplink data, downlink control, beam management). This segmentation allows necessary LBT procedures to be performed while skipping unnecessary ones, maintaining spectrum fairness where needed and improving efficiency where appropriate.
Solution Approach 2:
The patent applies channel access procedures partially - only when necessary for specific transmission types and directions. Instead of requiring LBT for all transmissions, the system applies it selectively based on configuration parameters, achieving adequate spectrum fairness without the performance penalty of universal application.
3Productivity
If different channel access procedures are configured for different transmissions, then communication performance is improved, but system complexity increases
Solution Approach 1:
The patent implements a universal configuration framework where a single set of RRC parameters and MAC-CE commands can configure channel access procedures for multiple transmission types and directions. The gNB uses multi-functional configuration messages that can apply to different uplink and downlink transmissions, reducing the need for separate configuration mechanisms and thereby reducing system complexity despite supporting differentiated procedures.
Solution Approach 2:
The patent enables the UE to autonomously determine which channel access procedure to apply based on pre-configured parameters and current transmission conditions. The UE uses self-service logic to select appropriate LBT parameters from configured sets based on the transmission type, direction, and priority, reducing the signaling overhead and management complexity that would result from explicit gNB commands for each transmission.
Data Source
AI summary
An apparatus and a method of wireless communication are provided. The method by a user equipment (UE) includes being configured, by a base station, with a first parameter and/or a second parameter, wherein the first parameter comprises information relevant to a channel access procedure application for a first transmission, and/or the second parameter comprises information relevant to a channel access procedure application for a second transmission. This can solve issues in the prior art, provide a channel access relevant indication for more than one scheduled uplink transmission by a same downlink control indicator (DCI) in a shared spectrum, reduce signaling overhead, provide a good communication performance, and/or provide high reliability.