Non-coherent PUCCH Format for Single-Carrier Waveform
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Solution Overview
Problem
Current wireless communication systems face challenges with signal attenuation and blockage in complex environments, leading to inefficiencies in wireless channel measurement and resource management, particularly due to increased phase noise and peak-to-average power ratio (PAPR) at higher frequencies and subcarrier spacings.
Innovation Solution
The implementation of a non-discrete Fourier transform (DFT) based single-carrier waveform for physical uplink control channel (PUCCH) transmission, which reduces computation complexity and PAPR, and uses non-coherent time-based formats to mitigate phase noise, allowing for efficient code-division multiplexing of user equipment (UEs) using orthogonal or non-orthogonal cover codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If orthogonal frequency division multiplexing (OFDM) is used for wireless communication, then data transmission capacity is improved, but peak-to-average power ratio (PAPR) increases
Solution Approach 1:
The patent replaces the traditional OFDM waveform generation mechanism with a sequence-based modulation mechanism. Instead of using inverse fast Fourier transform (IFFT) to generate OFDM signals, the invention directly generates time-domain sequences (such as Zadoff-Chu sequences or Gold sequences) that are then modulated onto carrier waves. This substitution eliminates the high PAPR characteristic of OFDM while maintaining spectral efficiency and data transmission capacity.
2Productivity
If higher frequencies and subcarrier spacings are used, then bandwidth utilization is improved, but phase noise increases
Solution Approach 1:
The patent changes the fundamental parameters of the transmission system by abandoning the subcarrier spacing parameter inherent to OFDM and instead using time-domain sequence lengths and cyclic shifts. By operating in the time domain rather than frequency domain, the system can utilize higher frequencies without suffering from the phase noise that plagues high-subcarrier-spacing OFDM systems, as the sequence-based approach is more robust to phase variations.
3Reliability
If coherent PUCCH formats are used, then transmission reliability is improved, but computation complexity increases
Solution Approach 1:
The patent extracts and removes the reference signal (RS) component from the PUCCH transmission structure. In traditional coherent PUCCH formats, dedicated RS resources are required for channel estimation and coherent detection. The invention achieves reliable transmission without these separate RS resources by using non-coherent detection methods that rely on the inherent properties of the selected sequences (such as constant amplitude zero autocorrelation properties), thereby eliminating the computation complexity associated with coherent channel estimation while maintaining transmission reliability.
4Productivity
If code division multiplexing is implemented, then resource utilization is improved, but interference mitigation becomes more difficult
Solution Approach 1:
The patent inverts the traditional code division multiplexing approach by having multiple users share the same time-frequency resources with the same base sequence, but differentiating them through different cyclic shifts of that sequence. This inversion of the multiplexing strategy (from code-based to cyclic-shift-based separation) simplifies interference mitigation because the orthogonal properties of cyclic shifts are more robust to multipath fading and do not require precise synchronization, thereby reducing the difficulty of detecting and measuring interference while maintaining high resource utilization.
Data Source
AI summary
Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for control signal transmission. One aspect provides a method for wireless communication by a user equipment (UE). The method generally includes receiving, from a base station (BS), a message indicating multiple configurations for physical uplink control channel (PUCCH) transmission; selecting, from a sequence database, a sequence to be used for the transmission of a PUCCH in accordance with one of the multiple configurations indicated by the message from the base station; and transmitting the PUCCH using the selected sequence.