UE Capability Signaling via RACH for 5G Coverage
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in efficiently signaling user equipment (UE) capabilities during the initial access procedure, leading to suboptimal performance due to inadequate coverage and power management for UEs with varying capabilities.
Innovation Solution
The method involves UE devices transmitting an indication of reduced capabilities based on reference signal received power (RSRP) thresholds, allowing for early and flexible capability signaling, which can occur before or after establishing a radio resource control (RRC) connected state, enabling better resource allocation and power savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If UE capability signaling is delayed until after RRC connection establishment, then signaling overhead during initial access is reduced, but coverage for UEs with reduced capabilities deteriorates
Solution Approach 1:
The patent applies preliminary action by enabling UE capability indication to be transmitted during the RACH procedure (in Msg1 or Msg3) before RRC connection establishment. This allows the base station to be aware of reduced capabilities early in the access process, ensuring appropriate coverage and resource allocation for reduced capability UEs while still reducing overall signaling overhead compared to traditional post-connection capability reporting.
2Reliability
If UE capability indication is transmitted during RACH procedure, then coverage for reduced capability UEs is improved, but device complexity increases
Solution Approach 1:
The patent merges UE capability indication with existing RACH messages (Msg1 preamble or Msg3 payload) rather than creating a separate signaling mechanism. This combining approach allows reduced capability UEs to indicate their status using already-transmitted uplink resources, improving coverage without significantly increasing device complexity as the same hardware and protocol stack handle both random access and capability signaling.
3Use of energy by moving object
If premium UEs temporarily switch to reduced capabilities, then power savings are achieved, but productivity decreases
Solution Approach 1:
The patent implements dynamic capability switching where premium UEs can temporarily indicate reduced capabilities based on current conditions (e.g., during initial access or specific service scenarios). This dynamic adjustment allows UEs to optimize power consumption by using reduced capability modes when appropriate, while maintaining the ability to switch back to full capabilities when higher productivity is needed, creating a flexible energy-performance tradeoff mechanism.
Data Source
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AI summary
The present disclosure relates to methods and devices for wireless communication of an apparatus, e.g., a UE and/or a base station. In one aspect, the apparatus may receive, from a base station, at least one SSB. The apparatus may also determine a RSRP of the at least one SSB. Additionally, the apparatus may transmit, to the base station if the RSRP of all of the at least one SSB is less than a threshold, an indication of a reduced UE capability of the UE during a RACH procedure. The apparatus may also transmit, to the base station if the RSRP of one of the at least one SSB is greater than or equal to the threshold, the indication of the reduced UE capability of the UE after entering into a RRC connected state upon completion of the RACH procedure.