Multi-tone PRACH Frequency Hopping for Unlicensed Spectrum
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Solution Overview
Problem
Narrowband communications using unlicensed frequency spectrum face PSD and bandwidth restrictions, making it challenging to support PRACH bandwidths like six RBs or single tone-based PRACH transmissions.
Innovation Solution
Implementing various frequency hopping configurations, such as first-level, second-level, and third-level frequency hopping, for multi-tone PRACH transmissions, allowing different PRACH bandwidths (e.g., 15 kHz, 45 kHz, 60 kHz, 180 kHz) with specific transmission powers, to overcome PSD and bandwidth limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If six RB based PRACH bandwidth or single tone-based PRACH bandwidth is used, then device complexity is reduced and power amplifier efficiency is improved, but PSD restrictions and bandwidth requirements for narrowband communications using unlicensed frequency spectrum cannot be met
Solution Approach 1:
The patent implements dynamic frequency hopping configurations that allow the PRACH transmission to adapt its bandwidth and frequency position based on unlicensed spectrum availability and PSD requirements. The system can switch between different bandwidth configurations (six RB, single tone, or other bandwidths) and hop between frequency positions to comply with regulatory requirements while maintaining operational flexibility.
Solution Approach 2:
The patent changes the frequency and bandwidth parameters of PRACH transmissions dynamically. By implementing frequency hopping with configurable hop sizes and patterns, the system can adjust its spectral footprint to meet PSD restrictions and bandwidth requirements of unlicensed spectrum operations, while still supporting narrowband device requirements.
2Adaptability or versatility
If frequency hopping is applied to spread PRACH segments in channel bandwidth, then occupied channel bandwidth requirements are met, but transmission complexity increases
Solution Approach 1:
The patent divides the PRACH transmission into multiple segments that can be frequency-hopped independently. Each segment can be transmitted on different frequency positions, allowing the system to meet occupied bandwidth requirements through distributed transmission while reducing the complexity of managing continuous wideband transmissions.
Solution Approach 2:
The patent implements periodic frequency hopping patterns where PRACH segments are transmitted at regular intervals across different frequency positions. This periodic structure simplifies the transmission logic compared to arbitrary frequency changes, as the hopping pattern can be predetermined and synchronized between transmitter and receiver.
Data Source
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AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. In one configuration, the apparatus may receive, from a base station, first information associated with one or more resources allocated for at least one PRACH transmission. In one aspect, the one or more resources may be allocated in an unlicensed spectrum. In another aspect, the one or more resources may be allocated based on a multi-tone PRACH bandwidth. The apparatus may also receive second information associated with a frequency hopping configuration from the base station. In one aspect, the frequency hopping configuration may be associated with at least one of the one or more allocated resources or the multi-tone PRACH bandwidth. The apparatus may transmit, to the base station, the at least one PRACH transmission using the one or more allocated resources within the multi-tone PRACH bandwidth and the frequency hopping configuration.