Random Access Channel Procedure for Unlicensed Spectrum
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Solution Overview
Problem
In unlicensed wireless networks, the performance of downlink beams for data transfer is affected by congestion in addition to Reference Signal Received Power (RSRP), leading to challenges in reliable Random Access Channel (RACH) procedure execution.
Innovation Solution
A method and system for performing random access channel procedure in unlicensed operation, where a User Equipment (UE) determines measurement metric values for Synchronization Signal Blocks (SSBs) and Channel State Information-Reference Signals (CSI-RSs), selects candidate beams based on these metrics, and optimizes message3 scheduling to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If downlink beam selection is based only on RSRP of SSB/CSI-RS, then the selection process is simple, but the performance in unlicensed operation deteriorates due to congestion not being considered
Solution Approach 1:
The patent changes the selection parameters from considering only RSRP to considering multiple parameters including RSRP, RSSI, and channel congestion metrics. This allows the beam selection to account for both signal quality and channel conditions, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The patent introduces feedback mechanisms where the UE reports channel conditions and congestion information back to the network, enabling dynamic beam selection adjustments. This feedback loop ensures that beam selection adapts to changing channel conditions while maintaining reasonable complexity.
2Ease of operation
If RACH procedure is performed in unlicensed spectrum without considering channel congestion, then the procedure is straightforward, but transmission failures increase due to congestion
Solution Approach 1:
The patent performs preliminary channel assessments and congestion checks before initiating the RACH procedure. By evaluating channel conditions in advance and selecting appropriate beams based on congestion metrics, the system prepares the transmission environment beforehand, reducing failures while maintaining procedural simplicity.
Solution Approach 2:
The patent makes the RACH procedure dynamic by allowing beam selection and transmission parameters to adapt based on real-time channel congestion conditions. This dynamic adjustment enables the system to respond to changing unlicensed spectrum conditions, improving reliability without significantly complicating the procedure.
3Device complexity
If message3 scheduling does not account for channel status, then scheduling is simple, but transmission reliability deteriorates in congested unlicensed channels
Solution Approach 1:
The patent changes the scheduling parameters to include channel status indicators and congestion metrics alongside traditional scheduling considerations. This allows the message3 scheduling to account for unlicensed channel conditions, improving transmission reliability while keeping the scheduling process manageable through standardized parameter evaluation.
Data Source
AI summary
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services.Embodiments herein disclose a method for performing random access channel procedure by a UE (300). The method includes determining a first measurement metric value and a second measurement metric value for one of a plurality of SSBs and a plurality of CSI-RSs. The method includes selecting one of a first set of SSBs and a first set of CSI-RSs from one of the plurality of SSBs and the plurality of CSI-RSs based on the first measurement metric. The method selects a second set of SSBs and a second set of CSI-RSs from one of the first set of SSBs and the first set of CSI-RSs based on the second measurement metric and determines a selection criteria and selects one of at least one candidate SSBs and at least one candidate CSI-RS from one of the second set of SSBs and the second set of CSI-RSs based on the selection criteria.