NR-Light UE Initial UL BWP Determination via RACH Occasion
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Solution Overview
Problem
The existing random access procedure for NR-Light UE is not compatible with the RACH used by regular UEs, as it occupies less bandwidth, requiring a new procedure to facilitate efficient signal transmission with reduced power consumption and flexible latency.
Innovation Solution
A method for determining an initial uplink bandwidth part (BWP) for NR-Light UE based on synchronization information received from the base station, which may involve determining the initial UL BWP to be the same as the initial downlink BWP, a first PRB, a last PRB, or a centre PRB of the RACH occasion, ensuring successful random access procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a new random access procedure is designed for NR-Light UE with less bandwidth, then power consumption is reduced and latency flexibility is improved, but device complexity increases due to procedure incompatibility with regular UE
Solution Approach 1:
The patent segments the random access procedure by introducing separate RACH occasions and bandwidth parts (BWPs) for NR-Light UEs, distinct from regular UEs. This segmentation allows NR-Light UEs to use a simplified, low-bandwidth procedure while regular UEs continue using the existing procedure, resolving the contradiction by isolating the complexity to specific resource segments rather than requiring system-wide procedural changes
Solution Approach 2:
The patent introduces an intermediary mechanism through BWP configuration and RACH occasion association, where the network configures specific BWPs and RACH occasions that map between the downlink and uplink. This intermediary structure enables the transition from DL BWP to UL BWP determination without direct procedural complexity, allowing NR-Light UEs to efficiently determine their UL BWP through predefined mapping rules rather than complex signaling
2Reliability
If the initial UL BWP is determined based on RACH occasion association, then random access success rate is improved, but bandwidth resource utilization becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-configuring the association between RACH occasions and UL BWPs before the random access procedure begins. The network provides RACH occasion information that includes the mapping to initial UL BWP in advance, allowing the UE to determine its UL BWP without complex real-time calculations or additional signaling during the random access process, thereby improving success rate while managing complexity through upfront configuration
Solution Approach 2:
The patent changes the parameter determination approach by deriving UL BWP parameters (such as frequency location and bandwidth) from RACH occasion parameters rather than using fixed or independently configured values. This parameter change strategy creates a direct mathematical relationship between RACH occasion indices and UL BWP characteristics, improving reliability through consistent parameter mapping while simplifying bandwidth management through parameter derivation rather than independent configuration
Data Source
AI summary
Embodiments of the present application relate to a method and an apparatus for random access procedure. According to an embodiment of the present application, a method can include: receiving, at a user equipment (UE), synchronization information; and determining an initial uplink (UL) bandwidth part (BWP) for the UE based on a random access channel (RACH) occasion associated with the synchronization information. Embodiments of the present application provide methods for determining an initial UL BWP for the UE. Accordingly, embodiments of the present application can facilitate the implementation of the random access procedure for the NR-Light UE.