Interlace PRACH Design for NR-U Interference Management
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Solution Overview
Problem
Current wireless communication systems face interference and congestion issues due to the increasing demand for mobile broadband access, particularly in New Radio-Unlicensed (NR-U) networks, where viable implementations of interlace-based Physical Random Access Channel (PRACH) designs have yet to be effectively identified.
Innovation Solution
The solution involves adjusting the cyclic prefix (CP) length of uplink channels to match the CP length of the PRACH configuration, allowing for interlacing of PRACH channels with other uplink channels, thereby aligning them in terms of subcarrier spacing, CP, and symbol boundary to minimize interference and optimize resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interlace-based PRACH design is implemented in NR-U networks, then resource utilization efficiency is improved, but interference management complexity increases
Solution Approach 1:
The frequency band is divided into multiple interlaces, where each interlace consists of non-contiguous resource blocks. This segmentation allows PRACH signals to be distributed across different frequency resources, improving resource utilization while enabling independent interference management for each interlace through selective frequency domain filtering or nulling at the receiver side.
Solution Approach 2:
The patent transitions from traditional time-division or contiguous frequency-division multiplexing to a multi-dimensional interlace structure that combines frequency hopping with non-contiguous resource allocation. This dimensional change enables better statistical multiplexing of PRACH resources across multiple UEs while providing degrees of freedom for interference avoidance through interlace selection and frequency domain processing.
2Productivity
If multiple UEs access the network simultaneously, then network capacity is improved, but interference and congestion increase
Solution Approach 1:
Multiple PRACH resources from different UEs are merged into a unified interlace structure where each UE is assigned specific interlaces based on preambles and frequency hopping patterns. This merging approach enables statistical multiplexing gains, allowing the network to accommodate more simultaneous access attempts while the structured interlace assignment and frequency domain processing mitigate interference through resource orthogonalization and selective reception.
Data Source
AI summary
Physical Random Access Channel (PRACH) interlacing is disclosed. In a particular implementation, a method of performing wireless communications adjusting, by a user equipment (UE) based on a cyclic prefix (CP) length of a received Physical Random Access Channel (PRACH) configuration, CP length of one or more uplink channels to match the CP length of the PRACH configuration. The method additionally includes transmitting, by the UE, the one or more uplink channels interlaced with a PRACH channel that corresponds to the PRACH configuration. The PRACH channel and the one or more uplink channels are aligned.