NR PDCCH Orders for Unambiguous PRACH Path Loss Estimation
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Solution Overview
Problem
The existing PDCCH order mechanism for triggering random access procedures in New Radio (NR) is unclear regarding which CSI-RS to use for path loss estimation during PRACH transmission, leading to inconsistencies in determining the reference signal power for PRACH.
Innovation Solution
Introduce an additional bit (RS_indication_bit) in DCI format 1_0 to explicitly indicate whether the referenceSignalPower is provided by ss-PBCH-BlockPower or both ss-PBCH-BlockPower and powerControlOffsetSS, depending on the quasi-co-location relationship between CSI-RS and SSB, ensuring accurate path loss estimation for PRACH transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PDCCH order mechanism is used to trigger random access procedures, then random access can be initiated, but the reference signal power determination becomes unclear leading to inconsistencies
Solution Approach 1:
The patent introduces an intermediary indicator field in the PDCCH order that mediates between the downlink CSI-RS and the uplink PRACH transmission. This indicator explicitly specifies which downlink reference signal (SSB or CSI-RS) should be used for path loss estimation, thereby resolving the ambiguity in reference signal power determination while maintaining the random access initiation capability.
2Adaptability or versatility
If multiple CSI-RS resources are configured for path loss estimation, then path loss estimation options increase, but determining which CSI-RS to use becomes ambiguous
Solution Approach 1:
The patent implements a feedback mechanism where the network provides explicit indication through the PDCCH order about which downlink reference signal should be used for path loss estimation. This feedback eliminates the ambiguity in selecting among multiple configured CSI-RS resources, allowing the UE to accurately determine the reference signal power without complex selection logic.
Data Source
AI summary
Methods, systems, and storage media are described for random access procedures triggered based on physical downlink control channel (PDDCH) orders. Other embodiments may be described and/or claimed.