Zadoff-Chu Sequence Generation for 5G Bandwidth Extension
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Solution Overview
Problem
Existing methods for bandwidth extension in 5G communication systems, such as those proposed in NPL 2, increase the Peak-to-Average Power Ratio (PAPR) of Demodulation Reference Signals (DMRS) due to the use of short Zadoff-Chu sequences, leading to higher manufacturing costs for amplifiers in Beyond 5G scenarios with increased device connectivity and higher frequency usage.
Innovation Solution
A terminal and base station apparatus configuration that generates a Zadoff-Chu sequence based on the extended number of subcarriers after bandwidth extension, using a sequence length equal to or longer than the largest prime number not exceeding the extended subcarriers, to reduce PAPR by eliminating discontinuous portions in the sequence, thereby reducing the PAPR of the DMRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cyclic extension is applied to extend bandwidth for PAPR reduction, then amplifier cost is reduced, but sequence discontinuity increases PAPR
Solution Approach 1:
The patent applies preliminary action by generating the Zadoff-Chu sequence with length corresponding to the extended bandwidth (1+α)M subcarriers before the cyclic extension is applied. This preliminary sequence generation ensures continuity in the time-domain signal after cyclic extension, preventing PAPR increase while still achieving the desired bandwidth extension for PAPR reduction.
2Device complexity
If short Zadoff-Chu sequence is used for bandwidth extension, then sequence generation is simplified, but PAPR increases due to discontinuous portions
Solution Approach 1:
The patent changes the key parameter of sequence length from the original M subcarriers to the extended bandwidth (1+α)M subcarriers. By generating the Zadoff-Chu sequence with this extended length, the patent maintains sequence continuity after cyclic extension while achieving bandwidth extension, thus reducing PAPR without significantly increasing generation complexity.
3Use of energy by moving object
If bandwidth extension is performed using cyclic extension, then frequency efficiency is reduced, but PAPR is reduced
Solution Approach 1:
The patent introduces a dynamic bandwidth extension factor α that can be adjusted to balance between PAPR reduction and frequency efficiency. By making the extension ratio可调 (adjustable), the system can dynamically optimize the trade-off between these two parameters based on specific communication conditions and requirements.
Data Source
AI summary
An uplink reference signal generation unit that generates a reference signal, and a reception unit that receives control information at least including information related to the number of allocation subcarriers and bandwidth extension transmitted from the base station apparatus are included. The uplink reference signal generation unit generates, by generating a Zadoff-Chu sequence based on the number of subcarriers after extension calculated based on the information related to the number of the allocation subcarriers and the bandwidth extension and cyclically extending the generated Zadoff-Chu sequence, a reference signal sequence having a sequence length whose number is equal to the number of the subcarriers after extension.