Reference Signal Sequence Initialization for PAPR Reduction
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Solution Overview
Problem
The 5G mobile communication system faces challenges in reducing the peak-to-average power ratio (PAPR) of reference signals, such as CSI-RS and DMRS, which increases the dynamic range of power amplifiers and implementation costs due to repeated sequence values across multiple ports in an OFDM symbol.
Innovation Solution
The method involves generating reference signals with different sequence initialization values for each CDM group or port, using techniques like adding or multiplying the CDM group index or port index to the OFDM symbol position, to prevent sequence value repetition and improve PAPR characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If reference signals use repeated sequence values across multiple ports in an OFDM symbol, then implementation is simplified, but PAPR increases and dynamic range of power amplifiers increases
Solution Approach 1:
The patent applies local quality by making the sequence initialization port-dependent. Different ports use different initialization values (e.g., different cyclic shifts), so that while maintaining the overall structure, local variations in sequence values reduce PAPR without complicating the overall implementation framework
Solution Approach 2:
The patent changes the initialization parameter (cinit) based on the port index or cyclic shift value. By modifying this parameter locally for different ports, the sequence values vary in a controlled manner that reduces peak power while maintaining the systematic approach to reference signal generation
2Device complexity
If reference signals use repeated sequence values across multiple ports, then sequence generation is simplified, but dynamic range of power amplifiers increases
Solution Approach 1:
The sequence generation process maintains simplicity through a systematic approach while introducing local variations via port-dependent initialization. The base sequence generation remains simple, but the initialization value adapts locally to each port's requirements, reducing dynamic range without significantly increasing overall complexity
Solution Approach 2:
The initialization parameter cinit is changed based on port index or cyclic shift, allowing the sequence generation to adapt to different ports' needs. This parameter modification reduces the dynamic range requirement while keeping the generation process systematic and manageable
3Ease of manufacture
If sequence initialization is port-independent, then implementation cost is reduced, but PAPR and dynamic range increase
Solution Approach 1:
The patent introduces port-dependent initialization as a relatively simple modification to the existing framework. By using the port index or cyclic shift value to determine the initialization parameter, the system achieves PAPR reduction without requiring complex processing or additional hardware, thus keeping implementation costs relatively low
Data Source
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AI summary
The disclosure relates to a method, performed by a user equipment (UE), of transmitting or receiving signals in a wireless communication system, and in an embodiment, the UE transmits, to a base station (BS), UE capability information regarding sequence initialization of a demodulation reference signal (DMRS), receives, from the BS, DMRS configuration information determined based on the UE capability information, and receives the DMRS from the BS based on the DMRS configuration information, wherein the DMRS is generated based on a sequence initialization parameter determined based on a code division multiplexing (CDM) group identifier included in the DMRS configuration information.