Uplink Demodulation Reference Signal Sequence Design
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Solution Overview
Problem
Current mobile communication systems face challenges in supporting high-speed data services due to resource shortages and the need for increased data transfer rates, a large number of connections, very low end-to-end latency, and high energy efficiency, which existing techniques such as small cell enhancement and non-orthogonal multiple access struggle to address effectively.
Innovation Solution
A method for transmitting a demodulation reference signal (DMRS) using a low peak to average power ratio (PAPR) sequence, specifically a length-6 sequence with 8-phase shift keying (PSK) symbols, is employed, along with frequency domain spectrum shaping (FDSS) and frequency division multiplexing across two antenna ports, to enhance PAPR performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional sequences are used for demodulation reference signal transmission, then the transmission can be performed with standard sequences, but the peak to average power ratio (PAPR) becomes high which reduces energy efficiency
Solution Approach 1:
The patent applies parameter changes by modifying the sequence structure from conventional formats to a specific length-6 sequence with 8-PSK symbols. This changes the fundamental parameters of the reference signal (sequence length, modulation type, symbol structure) to achieve lower PAPR values, directly improving energy efficiency while maintaining transmission functionality
Solution Approach 2:
The patent creates a composite sequence structure by combining multiple 8-PSK symbols into a length-6 sequence with specific phase relationships. This composite structure integrates multiple modulation symbols in a coordinated manner to achieve favorable PAPR characteristics that individual symbols cannot provide alone
2Object-generated harmful factors
If transform precoding is enabled for uplink, then PAPR performance can be improved, but the device complexity increases due to additional processing requirements
Solution Approach 1:
The patent applies preliminary action by pre-defining the length-6 sequence structure with 8-PSK symbols and predetermined phase relationships before transmission. The sequence is prepared in advance with optimized PAPR characteristics, eliminating the need for complex real-time transform precoding operations during transmission, thus reducing device complexity while maintaining PAPR performance
3Object-generated harmful factors
If frequency domain spectrum shaping is applied to the low PAPR sequence, then PAPR performance is further enhanced, but the device complexity and processing overhead increase
Solution Approach 1:
The patent employs a simplified approach by using a fixed, pre-defined length-6 sequence structure with 8-PSK symbols that inherently provides low PAPR characteristics. This disposable-like fixed structure eliminates the need for complex, adaptive frequency domain spectrum shaping operations, achieving acceptable PAPR performance with minimal processing complexity and overhead
Data Source
AI summary
The present disclosure provides a method for transmitting a demodulation reference signal. Specifically, the method performed by the terminal comprising: receiving, from a base station, a radio resource control (RRC) signaling including control information representing that transform precoding for an uplink is enabled; generating a low peak to average power ratio (PAPR) sequence based on a length-6 sequence; generating a sequence used for the demodulation reference signal based on the low PAPR sequence; and transmitting, to the base station, the demodulation reference signal based on the sequence used for the demodulation reference signal, wherein the length-6 sequence has an 8-Phase Shift Keying (PSK) symbol as each element of the sequence.