Beam-Based LBT Channel Access Procedure for 5G Wireless Systems
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Solution Overview
Problem
In wireless communication systems, especially in 5G networks, the existing channel access procedures face challenges in efficiently sharing channel occupancy time (COT) between base stations and user equipment during beam-based listen-before-talk (LBT) operations, leading to potential signal collisions and inefficiencies.
Innovation Solution
A method and apparatus for performing a channel access procedure that involves receiving information on LBT based on beams, obtaining channel occupancy time (COT), and transmitting signals within this COT, where the LBT is performed without random backoff, allowing for efficient sharing of COT between base stations and user equipment, thereby reducing signal collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam-based LBT with random backoff is performed for channel access, then collision avoidance between multiple users is improved, but channel access delay and access complexity increase
Solution Approach 1:
The patent segments the channel access procedure into two distinct types: Type 1 LBT with random backoff for initial channel access, and Type 2 LBT without random backoff for subsequent transmissions within the same COT. This segmentation allows the system to use the more efficient Type 2 procedure for ongoing communications while reserving Type 1 for initial access, thereby reducing overall access delay while maintaining collision avoidance where necessary.
Solution Approach 2:
The patent changes the backoff parameter dynamically based on the transmission type and COT status. For Type 1 LBT, a random backoff counter is used to avoid collisions. For Type 2 LBT within an established COT, the backoff counter is set to zero or skipped entirely, allowing immediate transmission. This parameter change resolves the contradiction by adapting the collision avoidance mechanism to the specific transmission context.
2Productivity
If COT is shared between base station and user equipment, then channel utilization efficiency is improved, but signal collision risk increases
Solution Approach 1:
The patent implements preliminary action by having the base station perform Type 1 LBT with random backoff to acquire the channel and establish a COT before allowing UE transmissions. This preliminary channel acquisition creates a protected time window where the base station has priority, and UEs can transmit without performing their own Type 1 LBT, thus sharing the COT efficiently while the base station's preliminary action prevents collisions.
Solution Approach 2:
The COT mechanism acts as an intermediary that mediates between base station and UE channel access. The base station acquires the COT through Type 1 LBT, and this COT serves as a shared resource that both the base station and UE can utilize. The intermediary COT structure allows efficient sharing while the base station's initial acquisition maintains collision avoidance, resolving the contradiction between efficiency and collision risk.
3Speed
If Type 2 LBT without random backoff is used for downlink transmission, then channel access speed is improved, but collision probability with other base stations increases
Solution Approach 1:
The patent introduces dynamics by allowing the LBT type to change based on the transmission context. Type 1 LBT with random backoff is used for initial channel acquisition when collision risk with other base stations is the primary concern. Type 2 LBT without random backoff is used for subsequent transmissions within the established COT when the base station already has channel priority. This dynamic switching resolves the contradiction by adapting the access speed to the current transmission phase.
Data Source
AI summary
The present disclosure discloses a method by which a terminal receives a downlink signal in a wireless communication system. In particular, the method receives information related to a listen-before-talk (LBT) based on at least one beam, performs LBT based on the at least one beam on the basis of the information, obtains a channel occupancy time (COT) on the basis of the performing of the LBT, and receives the downlink signal associated with the at least one beam within the COT.