CSI-RS to RACH Mapping for Wireless Handover Latency
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Solution Overview
Problem
Current wireless communication networks face challenges in achieving seamless mobility and efficient beam management during handovers, particularly in scenarios requiring high data rates, due to high overhead and latency associated with beam refinement procedures.
Innovation Solution
The implementation of a method where wireless devices receive a mapping between channel state information reference signals (CSI-RSs) and random access channel (RACH) configurations, allowing them to quickly access a narrow beam at a target cell without the need for continuous beam sweeping, thereby reducing overhead and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beam sweeping and beam refinement procedures are performed during handover, then beam accuracy and connection quality are improved, but overhead and latency increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring RACH resources and establishing mappings between CSI-RS beams and RACH occasions before handover occurs. The target gNB prepares beam-specific RACH resources in advance, and the source gNB provides indication information to the UE about these mappings prior to handover execution. This allows the UE to directly use the pre-established beam-RACH mapping during handover without performing time-consuming beam sweeping and refinement procedures, thereby reducing handover latency while maintaining beam accuracy.
2Reliability
If beam sweeping is performed continuously to maintain connection quality, then connection reliability is improved, but network overhead increases
Solution Approach 1:
The patent extracts the essential function of beam management by taking out only the necessary beam-RACH mapping information and providing it to the UE through indication messages from the source gNB. Instead of performing continuous beam sweeping to maintain connection quality, the system uses the pre-configured beam-specific RACH resources and mappings to maintain reliable connections during handover. This selective extraction of necessary information reduces network overhead while preserving connection reliability.
3Productivity
If narrow beams are used for high-gain transmission, then data rate is improved, but beam alignment complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the mapping between CSI-RS beams and RACH occasions before handover. The target gNB configures beam-specific RACH resources in advance, and the source gNB provides indication information to the UE about which RACH occasion corresponds to which beam. This allows the UE to directly access narrow high-gain beams during handover without performing complex real-time beam alignment procedures, thereby achieving high data rates while reducing beam alignment complexity.
Data Source
AI summary
A first exemplary embodiment provides a method performed by a wireless device (10) for handling communication of the wireless device in a wireless communication network, wherein the wireless communication network comprises a first radio network node (12) and a second radio network node (13), which first radio network node (12) serves the wireless device (10). The wireless device receives an indication indicating a mapping between one or more channel state information reference signals, CSI-RS, and one or more random access channel, RACH, configurations. The wireless device receives one or more CSI-RSs from the second radio network node (13), and selects a CSI-RS out of the one or more received CSI-RSs. The wireless device further initiates a random access procedure towards the second radio network node (13) using at least part of the RACH configuration mapped to the selected CSI-RS.