D2D Synchronization Signal and DM-RS Mapping for LTE Terminals
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently transmitting and receiving synchronization signals for device-to-device (D2D) communication, which is essential for improving connectivity and reducing costs in LTE systems.
Innovation Solution
A method for generating a synchronization signal and demodulation reference signal (DM-RS) using a synchronization reference identity (ID) in a wireless communication system, where the base sequence of the DM-RS is derived by dividing the synchronization reference ID by a predetermined value, and an orthogonal cover code (OCC) and cyclic shift are determined using specific bits of the synchronization reference ID.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronization signals are transmitted for D2D communication in LTE system, then device synchronization capability is improved, but system complexity and power consumption increase
Solution Approach 1:
The synchronization signal is divided into two distinct parts: Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS). PSS provides basic frame synchronization and SSS provides cell group ID and frame structure information. This segmentation allows devices to acquire synchronization in stages, reducing the complexity of processing a single complex signal while maintaining reliable synchronization capability.
Solution Approach 2:
The patent introduces Synchronization Identity (ID) as an intermediary parameter that links the PSS and SSS sequences. The ID determines both the root sequence for PSS and the cyclic shift for SSS, creating a unified framework that simplifies the relationship between the two synchronization signals and reduces overall system complexity.
2Reliability
If synchronization signals are transmitted for D2D communication, then device synchronization capability is improved, but power consumption increases
Solution Approach 1:
By segmenting synchronization into PSS and SSS, devices can perform sequential detection rather than processing a single complex signal simultaneously. Devices first detect PSS for frame timing, then use that information to efficiently detect SSS, reducing overall processing power requirements while maintaining synchronization reliability.
Solution Approach 2:
PSS is designed to provide preliminary frame synchronization information that prepares the device for subsequent SSS detection. The root sequence of PSS is determined by synchronization ID, which is reused in SSS generation, allowing devices to establish initial timing before decoding the secondary synchronization signal, thereby reducing power consumption in the synchronization process.
3Measurement precision
If base sequence of DM-RS is generated using synchronization reference ID, then demodulation accuracy is improved, but sequence generation complexity increases
Solution Approach 1:
The synchronization reference ID serves multiple functions: it determines the root sequence for PSS, the cyclic shift for SSS, and the base sequence for DM-RS. This multi-functionality ensures consistent phase references across different signal types, improving demodulation accuracy while avoiding the need for separate complex generation mechanisms for each signal.
Solution Approach 2:
The patent uses parameter changes in the Zadoff-Chu sequence generation by varying the root sequence index based on the synchronization ID. This parameter-based approach allows flexible and accurate sequence generation for different cells and signal types while maintaining a unified generation framework, balancing demodulation accuracy with generation simplicity.
Data Source
AI summary
The present invention relates to a method and an apparatus which enable a terminal to transmit a signal for device-to-device (D2D) communication in a wireless communication system. Specifically, the present invention transmits a synchronization signal for D2D communication and a demodulation reference signal (DM-RS) for demodulation of the synchronization signal, wherein the base sequence of the demodulation reference signal is generated using a synchronization reference ID.