RACH Occasion Mapping for Full-Duplex Random Access
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Solution Overview
Problem
Current wireless communication systems face challenges in selecting random access channel (RACH) occasions for full-duplex communication due to legacy validation rules that invalidate certain ROs, leading to increased latency and resource wastage when non-legacy UEs use traditionally invalid ROs.
Innovation Solution
Techniques are developed to indicate a set of ROs available for non-legacy UEs by indicating a mapping between SSBs/CSI-RSs and corresponding ROs, allowing full-duplex communication, even when these ROs are invalidated under legacy rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy validation rules are applied to invalidate certain ROs due to overlapping downlink transmissions, then half-duplex UEs can avoid interference, but full-duplex UEs experience increased latency and resource wastage
Solution Approach 1:
The patent segments the RO validation process by UE type. Legacy UEs continue to use traditional validation rules that invalidate ROs overlapping with downlink transmissions, while full-duplex UEs are provided with a separate indication of which ROs are valid for their group. This segmentation allows each UE type to operate under appropriate validation rules without compromising the other.
Solution Approach 2:
The patent creates a universal RO indication mechanism that serves multiple functions: it provides validation information for both half-duplex and full-duplex UEs, enables full-duplex operation when capability is present, and maintains backward compatibility with legacy UEs. The same downlink assignment indication structure is reused to convey both downlink resource information and RO validation information.
2Productivity
If full-duplex UEs use traditionally invalid ROs, then resource utilization improves, but beam determination accuracy deteriorates due to legacy validation rules
Solution Approach 1:
The patent introduces dynamic RO validation indications that adapt to full-duplex capability. Rather than using static legacy validation rules, the system dynamically indicates which ROs are valid for full-duplex UEs based on current downlink assignments and full-duplex capability detection. This dynamic approach ensures accurate beam determination while enabling efficient resource utilization.
3Measurement precision
If separate indication mechanisms are created for full-duplex ROs, then accuracy improves, but system complexity increases
Solution Approach 1:
The patent reuses the existing downlink assignment indication structure to convey RO validation information for full-duplex UEs. Instead of creating a separate indication mechanism, the same signaling structure serves dual purposes: indicating downlink resource assignments and providing RO validation information. This universal approach improves accuracy without significantly increasing system complexity.
Data Source
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AI summary
Certain aspects of the present disclosure provide techniques for facilitating the use of random access channel occasions for full-duplex communication. An example method performed by a user equipment (UE) in a first group of UEs may include receiving, from a base station (BS) of a wireless network, a first indication indicating, from a first plurality of random access channel occasions (ROs) not available for use by a second group of UEs within the wireless network, a set of ROs that are available for use by the first group of UEs within the wireless network, receiving a first signal of a plurality of signals transmitted by the BS, and transmitting, in response to receiving the first signal, a random access preamble in a first RO of the set of ROs based on a mapping between the first signal and the first RO.