PRACH Occasion Selection for SBFD Uplink Repetitions
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Solution Overview
Problem
The existing NR duplexing modes, such as TDD, result in latency, reduced coverage, and capacity due to fixed slot structures, especially in TDD deployments, and the introduction of sub-band non-overlapping full duplex (SBFD) aims to address these issues by allowing simultaneous DL and UL transmissions on different PRBs within an unpaired wideband NR cell.
Innovation Solution
The apparatus determines a set of PRACH occasions by receiving configuration information for both uplink and SBFD resources, identifying a starting PRACH occasion for each frequency resource index, and performs PRACH transmissions based on this set to optimize PRACH procedures in SBFD environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If TDD duplexing mode is used with fixed slot structure, then device complexity is reduced, but latency increases and coverage and capacity are reduced
Solution Approach 1:
The patent introduces dynamic slot structure in SBFD mode, allowing the gNB to flexibly configure uplink and downlink slots based on traffic demands. This dynamic configuration enables reduced latency by allowing UEs to transmit PRACH in the nearest available uplink slot rather than waiting for fixed periodic opportunities, while maintaining manageable complexity through standardized configuration procedures.
2Device complexity
If TDD duplexing mode is used with fixed slot structure, then device complexity is reduced, but coverage and capacity are reduced
Solution Approach 1:
SBFD enables dynamic adjustment of uplink and downlink resource allocation based on real-time traffic conditions. This flexibility improves coverage and capacity by ensuring adequate uplink resources are available when needed, while the gNB maintains control through standardized configuration signaling that keeps implementation complexity manageable.
Solution Approach 2:
The patent changes the temporal parameters of resource allocation by introducing flexible slot configurations in SBFD mode. This allows optimization of uplink resource availability for PRACH transmissions, improving coverage and capacity without requiring complex device architectures.
3Productivity
If PRACH occasions are distributed across uplink and SBFD resources, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent segments PRACH occasions into different types (first type in uplink slots, second type in SBFD slots) with distinct determination rules. This segmentation allows efficient PRACH transmission by directing UEs to appropriate resource types based on their needs, while maintaining manageable complexity through clear differentiation of determination procedures for each type.
Solution Approach 2:
The gNB acts as an intermediary by providing configuration information that guides UEs on PRACH occasion selection. This intermediary role simplifies UE complexity by offloading the decision-making to standardized configuration procedures while enabling productive use of both uplink and SBFD resources.
4Loss of time
If starting PRACH occasion is determined from SBFD resources, then loss of time is reduced, but device complexity increases
Solution Approach 1:
The patent implements dynamic determination of starting PRACH occasions based on the type of resource (uplink or SBFD). This dynamic approach reduces access delay by allowing UEs to immediately use available SBFD uplink resources when configured, while maintaining manageable complexity through distinct determination rules for different resource types that are standardized in the configuration.
Data Source
AI summary
Example embodiments of the present disclosure relate to a solution for determining a set of physical random access channel (PRACH) occasions. In the solution, a first apparatus receives, from a second apparatus, configuration information indicating a plurality of PRACH occasions comprising PRACH occasions in uplink resource and PRACH occasions in sub-band non-overlapping full-duplex (SBFD) resource; determines, based on the configuration information, and for each frequency resource index for frequency multiplexed PRACH occasions, a starting PRACH occasion of a set of PRACH occasions for a PRACH transmission with preamble repetitions from the PRACH occasions in uplink resource and the PRACH occasions in SBFD resource, and performs, to the second apparatus, the PRACH transmission based at least in part on the starting PRACH occasion of the set.