Hybrid RAR Resource Mapping for Random Access Decoding
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in random access response decoding and resource utilization during the random access procedure, particularly due to limited payload sizes and excessive resource consumption in current RAR message handling methods.
Innovation Solution
A hybrid resource mapping approach is employed, combining group common PDCCH signaling with separate PDSCHs for different UEs, using configuration tables in DCI to optimize payload size and reduce decoding complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RAR messages are aggregated into a single PDSCH scheduled by one PDCCH, then resource utilization efficiency is improved, but the payload size is limited by the link budget of cell-edge UEs which reduces multiplexing capacity
Solution Approach 1:
The patent segments the aggregated RAR messages into multiple codeblock groups, where each codeblock group can be independently decoded by UEs. This segmentation allows the system to maintain efficient resource utilization through aggregation while increasing multiplexing capacity by distributing payload across multiple decodable segments, resolving the contradiction between resource efficiency and multiplexing capacity.
Solution Approach 2:
The patent extracts critical RAR information into a compact format that can be efficiently transmitted within the PDSCH payload constraints. By extracting and prioritizing essential access response data, the system maximizes the effective use of limited payload space while maintaining the ability to serve multiple UEs, thus balancing resource utilization with multiplexing capacity.
2Reliability
If RAR messages are scheduled individually for each UE, then payload size requirements are met, but time/frequency resources are unnecessarily consumed
Solution Approach 1:
The patent merges multiple individual RAR scheduling operations into a single aggregated PDSCH transmission scheduled by one PDCCH. This combining approach maintains sufficient payload size for each UE's requirements while dramatically reducing time and frequency resource consumption by eliminating redundant control channel transmissions, thus resolving the contradiction between reliability and resource efficiency.
Solution Approach 2:
The patent creates a universal PDSCH structure that can serve multiple UEs simultaneously with different payload requirements. The aggregated RAR message format is designed to be universally applicable across multiple UEs in the RACH occasion, allowing the system to meet individual payload needs while using a single efficient transmission mechanism, thereby reducing overall resource consumption.
3Reliability
If multiple PDCCHs are monitored for individual RAR scheduling, then each UE receives its RAR message, but decoding complexity increases unnecessarily
Solution Approach 1:
The patent combines multiple individual PDCCH monitoring operations into a single PDCCH monitoring event. By aggregating RAR messages and scheduling them through one common PDCCH, the system maintains reliable RAR delivery to all UEs while reducing blind decoding complexity from multiple PDCCH candidates to a single control channel, thus resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent introduces an intermediary aggregated RAR message structure that mediates between individual UE requirements and collective resource efficiency. This intermediate aggregation layer allows UEs to receive their specific RAR information while monitoring only one common PDCCH, reducing decoding complexity while maintaining reliable message delivery through the structured aggregation format.
Data Source
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AI summary
Wireless communication devices, systems, and methods related to mechanisms to implement improved RAR decoding performance and resource utilization efficiency in a RACH procedure. A PDCCH with common search space encodes a DCI with configuration information that schedules separate PDSCHs for different UEs/UE groups. When sending a RAR message, the PDCCH includes a DCI with a configuration field to signal multiple DMRS resources with corresponding PDSCH. Each sub-field of the configuration field may include one or multiple bits. When one bit per sub-field, the bit is a flag that when asserted leads the UE to blind decode the PDSCH associated with that DMRS resource. When multiple bits, it includes a flag field as well as one or more bits that include least significant bits of UE identifier (or group identifier). The UE locates its identifier (or group identifier), and limits decoding to that PDSCH with corresponding DMRS resource.