PRACH Frequency Multiplexing for NR-Lite Bandwidth Limits
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Solution Overview
Problem
The existing NR system does not adequately meet the requirements of reduced capability UE (NR-lite) in terms of low cost, complexity, coverage enhancement, and power saving, as it exceeds the limited receiving frequency domain bandwidth of these devices, particularly in frequency-division multiplexing (FDM) configurations.
Innovation Solution
A frequency-division multiplexing method is implemented, where the total bandwidth of physical random access channels (PRACHs) is determined to match the capability of reduced capability UE by limiting the bandwidth occupied by PRACHs for FDM, using a first parameter that configures PRACH FDM factors and frequency resources based on the UE's capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the NR system uses conventional frequency-division multiplexing configurations for physical random access channels, then the system can support high-rate communication services, but the total bandwidth occupied by PRACHs exceeds the limited receiving frequency domain bandwidth of reduced capability UE (NR-lite)
Solution Approach 1:
The patent segments the frequency domain resources by dividing the PRACH bandwidth into multiple controllable segments. The network device determines a first parameter that configures the total bandwidth occupied by PRACHs for FDM, allowing the system to allocate frequency resources in manageable units that can be adapted to different UE capabilities, including NR-lite devices with limited receiving bandwidth.
Solution Approach 2:
The patent changes the bandwidth parameter of PRACHs dynamically based on UE capability. By determining a first parameter that configures the total bandwidth occupied by PRACHs for FDM, the system can adjust the frequency domain width of PRACHs to match the receiving bandwidth capability of reduced capability UE, while maintaining conventional configurations for full-capability UEs.
2Adaptability or versatility
If the NR system configures PRACH FDM to support reduced capability UE with limited bandwidth, then bandwidth compatibility is improved, but the communication rate capability for high-end services is reduced
Solution Approach 1:
The patent implements dynamic bandwidth configuration for PRACH FDM based on UE capability identification. The network device determines the first parameter according to the capability of the reduced capability UE, allowing the system to switch between bandwidth configurations dynamically. This enables the same PRACH resources to serve both NR-lite devices (with limited bandwidth) and full-capability UEs (requiring higher rates) without sacrificing overall system productivity.
3Device complexity
If the NR system uses standard PRACH FDM factors and frequency resources, then the system maintains simplicity in configuration, but it cannot meet the specific requirements of reduced capability UE for low cost, complexity, and power saving
Solution Approach 1:
The patent creates a universal configuration mechanism that serves multiple UE types through a single framework. The first parameter determined by the network device can configure PRACH FDM for both conventional UEs and reduced capability UE, making the same configuration system multi-functional. This maintains relative simplicity while adding adaptability, as the existing PRACH FDM structure is extended rather than replaced.
Data Source
AI summary
A frequency-division multiplexing method includes: determining a first parameter, where the first parameter is configured to determine a total bandwidth occupied by physical random access channels for performing frequency-division multiplexing.