UE Interference Measurement for 5G Random Access
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Solution Overview
Problem
In 5G and LTE networks, the random-access procedure for user equipment (UE) is often hindered by cross-link interference (CLI) from nearby UEs, leading to performance degradation and potential failure in establishing connections during transitions from idle or inactive to connected modes.
Innovation Solution
The UE measures interference before initiating the access procedure and signals interference avoidance information to the network, allowing the network to schedule downlink messages on resources with minimal interference, thereby reducing the impact of CLI and ensuring successful access procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs random-access procedure in idle or inactive mode, then the UE can establish connection with the network, but the access procedure may fail due to cross-link interference from nearby UEs
Solution Approach 1:
The network performs preliminary actions by determining CLI measurement configurations and resource allocations before the UE initiates the random-access procedure. The network sends CLI measurement configurations to the UE in advance, and pre-determines downlink message resources based on expected interference conditions, enabling the UE to perform measurements and select appropriate resources before actual access attempts.
Solution Approach 2:
The UE performs feedback by measuring CLI on configured uplink resources and reporting measurement results or selecting downlink message resources based on measured interference levels. This feedback loop allows the network to adapt resource allocations and transmit power based on actual interference conditions observed by the UE, improving access success rates in interfered environments.
2Reliability
If the network schedules downlink messages on standard resources, then the scheduling is simple, but the downlink messages may be received with degraded performance due to CLI
Solution Approach 1:
The network applies local quality by determining specific downlink message resources tailored to individual UE interference conditions. Instead of uniform resource allocation, the network configures CLI measurement resources and determines downlink message resources on a per-UE basis, adapting resource selection to local interference characteristics observed by each UE.
Solution Approach 2:
The resource scheduling becomes dynamic as the network determines downlink message resources based on real-time CLI measurement results reported by UEs. The network can adjust resource allocations, transmit power, and timing based on measured interference levels, transitioning from static to dynamic scheduling to optimize reception quality in varying interference conditions.
3Reliability
If the UE uses standard random-access procedure without interference measurement, then the procedure is simple, but the access may fail due to undetected CLI
Solution Approach 1:
The network performs preliminary configuration by providing CLI measurement configurations to UEs before random-access attempts. This includes configuring measurement resources, thresholds, and reporting formats in advance, so UEs are prepared to measure and report interference conditions without adding complex ad-hoc procedures during actual access attempts.
Solution Approach 2:
The UE performs self-service by autonomously measuring CLI on configured resources and determining appropriate downlink message resources or reporting measurements without continuous network control. The UE independently evaluates interference conditions and makes resource selection decisions, reducing signaling overhead while improving access reliability.
Data Source
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Figure 5A
AI summary
There is provided a method at a user equipment, comprising: measuring interference in a radio resource control non-connected mode; including information of the measured interference in an uplink message of an access procedure; and causing reception of at least one downlink message of said access procedure on radio resources at least partially based on the transmitted information.