Configurable LBT Parameters for PRACH and PUCCH Channel Access
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Solution Overview
Problem
Current channel sensing mechanisms in unlicensed spectrum, such as Listen Before Talk (LBT), face challenges in efficiently managing channel access and reducing latency for random access channel (RACH) procedures, especially in scenarios with dense small cell deployments and stationary IoT devices, leading to potential interference and resource wastage.
Innovation Solution
Implementing configurable Listen Before Talk (LBT) schemes and parameters for Physical Random Access Channel (PRACH) and Physical Uplink Control Channel (PUCCH) transmissions based on the purpose of the transmission, including determining priority levels and contention window sizes, to optimize channel access and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Listen Before Talk (LBT) is applied for channel access in unlicensed spectrum, then coexistence with other radio access technologies is improved, but transmission latency increases due to channel sensing requirements
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting LBT parameters (such as contention window size, deferment period, and energy detection threshold) based on channel conditions, traffic type, and priority levels. This allows the system to optimize between coexistence performance and latency requirements for different transmission scenarios.
Solution Approach 2:
The patent introduces dynamic LBT parameter configuration where the base station can adjust LBT parameters in real-time based on channel occupancy, interference levels, and traffic requirements. This dynamic adaptation enables the system to respond to changing conditions and balance coexistence with latency performance.
2Reliability
If random back-off within contention window is performed upon channel occupation detection, then channel access fairness is improved, but access time and latency increase
Solution Approach 1:
The patent changes the contention window size parameter dynamically based on channel conditions and traffic priority. For high-priority traffic or when channel conditions favor faster access, the contention window can be reduced, thereby maintaining fairness while reducing access time and latency.
Solution Approach 2:
The patent segments the channel access procedure into different priority levels and traffic types, allowing different back-off behaviors for different categories of transmissions. This segmentation enables critical traffic to bypass lengthy back-off procedures while maintaining fairness for ordinary traffic.
3Productivity
If maximum channel occupancy time (MCOT) is enforced after channel access, then channel efficiency is improved, but transmission flexibility is reduced
Solution Approach 1:
The patent applies dynamic MCOT configuration where the maximum channel occupancy time is adjusted based on traffic requirements, channel conditions, and priority levels. This allows the system to maintain high channel efficiency for bulk data transmissions while providing flexibility for time-sensitive or intermittent traffic patterns.
Solution Approach 2:
The patent segments transmissions into different priority classes with different MCOT allowances. High-priority traffic may be granted shorter MCOT for faster re-access, while best-effort traffic can utilize longer MCOT for improved channel efficiency, thereby balancing both productivity and adaptability.
4Reliability
If RRM measurements are performed for congestion avoidance in unlicensed spectrum, then coexistence performance is improved, but measurement complexity and overhead increase
Solution Approach 1:
The patent makes RRM measurements multi-functional by using the same measurement infrastructure for both congestion avoidance and other radio resource management tasks. This universality reduces measurement complexity and overhead while maintaining improved coexistence performance through shared measurement data.
Solution Approach 2:
The patent recovers and reuses measurement data across different functions and time periods, reducing redundant measurements. By discarding temporary measurement results and recovering useful information for multiple purposes, the system reduces overall measurement complexity while maintaining coexistence performance.
Data Source
AI summary
Methods, a terminal device and a base station are disclosed for channel sensing in unlicensed spectrum. According to an embodiment, a terminal device determines to perform physical random access channel (PRACH) or physical uplink control channel (PUCCH) transmission in unlicensed spectrum. The base station determines one or more listen before talk (LBT) parameters for the PRACH or PUCCH transmission according to a purpose of the PRACH or PUCCH transmission.