PUCCH Resource Configuration in Two-Step RACH for HARQ Feedback
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in random access procedures due to separate messaging for uplink resource allocation and decoding status, leading to increased signaling overhead and inflexible channel structures.
Innovation Solution
Implementing a two-step random access procedure that signals PUCCH resource configuration through multiple mechanisms, including system information, PDCCH, and PDSCH, allowing UEs to determine PUCCH resources based on decoding success, thereby reducing overhead and accommodating different connection states and channel structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate message is used to convey uplink resource allocation information for decoding status transmission, then the BS can obtain decoding status feedback, but signaling overhead increases
Solution Approach 1:
The patent combines the random access response message (msgB) and uplink resource allocation information into a single message transmission. The uplink resource allocation for HARQ-ACK feedback is embedded within the msgB structure, eliminating the need for a separate dedicated message and thereby reducing signaling overhead while ensuring reliable delivery of resource allocation information.
Solution Approach 2:
The msgB message is designed to serve multiple functions simultaneously: it conveys the random access response, provides uplink resource allocation for HARQ-ACK transmission, and enables the BS to seek decoding status feedback. This multi-functional approach reduces the total number of messages required in the random access procedure.
2Adaptability or versatility
If PUCCH resource configuration is indicated in both PDCCH and PDSCH, then flexibility in resource allocation is improved, but device complexity increases
Solution Approach 1:
The patent divides the PUCCH resource configuration indication into two separate locations: PDCCH and PDSCH. The PDCCH carries a first indication of PUCCH resources, while the PDSCH carries a second indication. This segmentation allows the system to provide flexible resource allocation options while maintaining a structured approach that UEs can process systematically according to their decoding success.
Solution Approach 2:
The patent implements dynamic PUCCH resource allocation where the actual PUCCH resources used by the UE depend on the decoding outcome of msgB. If PDCCH decoding succeeds, the UE uses PUCCH resources indicated in PDCCH; if PDSCH decoding also succeeds, the UE may use PUCCH resources indicated in PDSCH. This dynamic behavior adapts resource allocation to actual channel conditions and decoding performance.
Data Source
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AI summary
Wireless communication devices, systems, and methods related to mechanisms to implement PUCCH resource configuration for two-step RACH for subsequent HARQ messaging. After a UE transmits msgA to a BS, the BS responds with msgB including a PUCCH resource indicator in a DCI of PDCCH, or a PUCCH resource indicator in PDSCH. The UE attempts to decode PDCCH or PDSCH, respectively. Upon decoding, the UE will use the configuration identified by the resource indicator. With the PUCCH resource configuration information, the UE signals a HARQ message.