Reference Signal Design for Wireless Coverage
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Solution Overview
Problem
Wireless communication systems face challenges in extending the coverage area of reference signals, such as CSI-RS, due to high path loss at high frequencies, which limits the communication range and efficiency.
Innovation Solution
The implementation of a π/2 BPSK modulation scheme with frequency domain spectral shaping and DFT-s-OFDM transmission, along with the transmission of filter coefficients from the base station to the UE, helps in reducing the peak-to-average power ratio (PAPR) of the reference signal, allowing for increased average power transmission and enhanced coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If reference signal transmit power is increased to improve coverage area, then coverage area is improved, but peak-to-average power ratio increases causing transmission inefficiency
Solution Approach 1:
The patent applies π/2 BPSK modulation instead of conventional QPSK modulation for reference signals. This parameter change in the modulation scheme fundamentally alters the signal characteristics, resulting in lower PAPR while maintaining the same coverage area benefits, thereby resolving the contradiction between coverage improvement and power efficiency
Solution Approach 2:
The patent introduces dynamic filter coefficient adjustment based on channel conditions. The base station can adaptively select different filter coefficients from a codebook to optimize the reference signal characteristics for current channel conditions, dynamically balancing coverage area and PAPR performance
2Area of stationary object
If filter coefficients are transmitted from base station to UE, then reference signal coverage is improved, but device complexity increases
Solution Approach 1:
The patent uses a pre-defined codebook of filter coefficients that both base station and UE possess. Instead of transmitting complex filter parameters, the base station simply indicates an index to the codebook entry, and the UE copies the corresponding coefficients from its local storage, dramatically reducing signaling overhead and processing complexity
Solution Approach 2:
The filter coefficients are pre-calculated and stored in a codebook before transmission. This preliminary preparation allows the base station to只需 indicate an index rather than transmit full coefficient data, and enables the UE to immediately use the coefficients without complex processing, thus improving coverage while minimizing added complexity
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A method of wireless communication is described. A user equipment (UE) may receive an indication of one or more filter coefficients used by a base station to filter a reference signal used by the UE to determine channel quality information (CQI). The UE may receive a reference signal from the base station, and may determine the CQI based on the received reference signal and the one or more filter coefficients. The UE may transmit the determined CQI to the base station.