PRACH Resource Co-existence for CBRA and CFRA
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently co-existing and configuring contention-based random access (CBRA) and contention-free random access (CFRA) resources and associations in Long Term Evolution (LTE) and New Radio (NR) cellular networks.
Innovation Solution
The proposed solution involves configuring CBRA and CFRA resources and associations in a way that allows for flexible co-existence, including overlapping, non-overlapping, and partly overlapping PRACH occasions, with specific parameters and configurations for each type of access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CBRA and CFRA resources are configured separately without overlap, then resource allocation is simple and clear, but resource utilization efficiency decreases and waste increases
Solution Approach 1:
The patent merges CBRA and CFRA resources by allowing CFRA occasions to be configured within CBRA occasions. Specifically, the network can configure a CFRA occasion that overlaps with a CBRA occasion in time and frequency, enabling both access types to share the same physical resources. This is achieved through configuration parameters that define PRACH occasions for both CBRA and CFRA, with the understanding that CFRA uses dedicated preambles while CBRA uses random preambles within the same occasion structure.
Solution Approach 2:
The patent makes PRACH occasions universal by designing them to serve dual purposes: they can function as CBRA occasions for general random access or as CFRA occasions for dedicated random access. The same time-frequency resources can be allocated to support both access types simultaneously, with the distinction made through preamble assignment and configuration parameters rather than separate resource allocations.
2Productivity
If CBRA and CFRA use the same PRACH occasions, then resource efficiency is improved, but access conflict and interference increase
Solution Approach 1:
The patent segments the PRACH resources by dividing preambles into two distinct sets: one set for CFRA (contention-free random access) and another set for CBRA (contention-based random access). Within the same PRACH occasion, UEs performing CFRA use preambles from the CFRA set, while UEs performing CBRA use preambles from the CBRA set. This segmentation eliminates interference between the two access types while maintaining resource efficiency through shared time-frequency resources.
Solution Approach 2:
The patent introduces configuration parameters as intermediaries that mediate between CBRA and CFRA resources. The network configures separate parameter sets for CFRA (including dedicated preamble indices and associated SSB/CSI-RS references) that coexist with CBRA parameters. These configuration intermediaries enable the system to manage and coordinate the shared resources without direct conflict, allowing both access types to operate simultaneously with proper resource allocation.
3Adaptability or versatility
If flexible PRACH occasion configurations are implemented, then adaptability to different network scenarios is improved, but system complexity increases
Solution Approach 1:
The patent implements dynamic configurability where PRACH occasions can be flexibly allocated and reconfigured based on network conditions and requirements. The system allows dynamic switching between different access types (CBRA and CFRA) within the same occasion structure, and enables dynamic adjustment of the number, timing, and frequency of PRACH occasions through configurable parameters. This dynamic approach provides adaptability to varying network scenarios while maintaining a unified configuration framework.
Solution Approach 2:
The patent utilizes parameter changes to achieve flexibility without increasing structural complexity. By configuring variables such as the number of PRACH occasions, their timing offsets, frequency locations, and associated preamble sets, the system can adapt to different network scenarios. The configuration parameters allow the network to adjust resource allocation dynamically through parameter modification rather than structural changes, maintaining system simplicity while achieving high adaptability.
Data Source
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AI summary
Enabling the co-existence of contention based random access (CBRA) and contention free random access (CFRA) is an effective technique to improve network flexibility and usage of network resources. In some embodiments, all available communication opportunities in the CBRA schedule and all available communication opportunities in the CFRA schedule may be used to generate a final schedule Different subsets of preamble indices are employed to ensure that both CBRA and CFRA communications can co-exist. In other embodiments, all available communication opportunities in the CBRA schedule, but only the dedicated communication opportunities in the CFRA schedule, may be used to generate a final schedule. As a result, a smaller subset of preamble indices is used.