Random Access Channel Frequency Multiplexing for NTN Handover Continuity
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Solution Overview
Problem
In non-terrestrial networks, such as those provided by satellites, the larger Doppler shifts and wider subcarrier spacing necessitate larger frequency allocations for random access channel (RACH) resources, leading to fragmented data transmissions and increased overhead due to concurrent handovers by multiple UEs, making efficient resource utilization and data transmission continuity challenging.
Innovation Solution
Configuring RACH resources for multiple beams in respective frequency regions, allowing for multiplexing and guard periods, thereby reducing frequency retune disruptions and conserving air interface resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger frequency allocations are used for RACH resources to accommodate larger Doppler shifts and wider subcarrier spacing, then the reliability of random access procedure is improved, but the resource utilization efficiency deteriorates due to fragmented data transmissions and increased overhead
Solution Approach 1:
The patent segments RACH resources into multiple frequency regions, with different beams associated with different frequency regions. This segmentation allows the system to allocate RACH resources more efficiently across the frequency spectrum, reducing fragmentation while maintaining the necessary frequency allocation size for reliable random access procedures in NTN environments with large Doppler shifts.
Solution Approach 2:
The patent introduces frequency multiplexing as an additional dimension for RACH resource allocation. By configuring RACH resources across multiple frequency regions rather than simply increasing the size of single-frequency allocations, the system achieves both improved reliability through adequate frequency allocation and maintained resource utilization efficiency through sophisticated frequency-domain resource management.
2Adaptability or versatility
If multiple beams are configured for concurrent handovers, then the adaptability of the network is improved, but the device complexity increases due to frequency retune disruptions and overhead management
Solution Approach 1:
The patent applies preliminary action by pre-configuring RACH resources for multiple beams in different frequency regions before handover operations. This allows UEs to perform random access procedures on appropriate frequency regions without requiring frequent frequency retuning during concurrent handovers, thereby reducing the complexity of frequency retune management while maintaining high network adaptability.
Solution Approach 2:
The patent introduces frequency region mapping as an intermediary mechanism that associates different beams with specific frequency regions. This mapping acts as a mediator that simplifies the complexity of managing multiple beams for concurrent handovers by providing a structured approach to frequency resource allocation, reducing frequency retune disruptions, and enabling more efficient overhead management.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive configuration information identifying locations of respective random access channel (RACH) resources for a plurality of beams associated with a non-terrestrial network, wherein the plurality of beams are associated with respective frequency regions. The UE may perform a RACH procedure with regard to the selected beam using a RACH resource associated with the selected beam. Numerous other aspects are provided.