LBT Control in Distributed Shared Cells
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Solution Overview
Problem
In shared cell deployments, different transmission points may operate under varying radio conditions and environments, leading to inefficient Listen Before Talk (LBT) procedures that can contribute to higher interference and unsynchronized data transmission.
Innovation Solution
A method is implemented in network nodes to determine, for each transmission point, whether an LBT procedure is necessary before signal transmission, allowing for controlled use of LBT in shared cells, thereby optimizing LBT scheduling across transmission points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LBT procedure is performed at all transmission points in shared cell, then channel access compliance is ensured, but interference increases and scheduling efficiency deteriorates
Solution Approach 1:
The patent segments the transmission points into different groups (first set and second set) with different LBT requirements. Transmission points in the first set perform LBT procedures while those in the second set do not, creating differentiated channel access behaviors across the network to reduce overall interference while maintaining compliance where necessary.
Solution Approach 2:
The patent applies different LBT procedures to different transmission points based on their local characteristics and requirements. Each transmission point is configured with specific LBT parameters (such as random backoff values, contention window sizes) tailored to its local environment, allowing optimized channel access behavior rather than uniform application across all points.
2Reliability
If LBT procedure is performed at all transmission points in shared cell, then regulatory requirements are met, but scheduling complexity and coordination overhead increase
Solution Approach 1:
The patent divides transmission points into distinct groups with different LBT configurations, allowing the network to meet regulatory requirements for certain points while simplifying scheduling for others. This segmentation reduces the overall coordination overhead by creating clear distinctions in LBT application across the transmission point population.
Solution Approach 2:
The patent enables dynamic adjustment of LBT parameters for different transmission points through network configuration messages. The eNB can independently control LBT behavior for each transmission point or group, allowing flexible adaptation to changing regulatory requirements and network conditions without increasing overall scheduling complexity.
3Reliability
If LBT procedure is performed before each transmission, then channel clarity is ensured, but transmission delay increases
Solution Approach 1:
The patent applies LBT procedures partially - only to transmission points in the first set that require channel access confirmation - rather than universally to all transmission points. This partial application maintains channel clarity where needed while avoiding unnecessary LBT delays for transmission points in the second set, reducing overall transmission latency.
Data Source
AI summary
The present disclosure relates to a method performed in a network node of a communication network, for facilitating downlink transmission in a shared cell served by a group of at least one Listen Before Talk (LBT) capable Transmission Point (TP). The method comprises determining, for each TP of the group, whether an LBT procedure is to be performed before signal transmission by said TP. The method also comprises, based on the determining, controlling the use of LBT procedures in the shared cell.