Narrow Band Synchronization Signal Frame Structure for Legacy Compatibility
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Solution Overview
Problem
Current mobile communication systems face challenges in supporting high data traffic, increased data rates, numerous connected devices, low latency, and energy efficiency, particularly for low-cost/low-specification terminals, which require efficient synchronization signal transmission and detection in narrow bands.
Innovation Solution
A method for transmitting and receiving synchronization signals in a newly defined frame structure for narrow band wireless communication systems, including specific frame configurations with multiple subframes and symbols, allowing efficient CP length detection and compatibility with legacy systems, while using a reduced subcarrier spacing and distinct symbol durations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a new frame structure is defined for narrow band communication, then compatibility with legacy systems is improved, but device complexity increases due to multiple subframe and symbol configurations
Solution Approach 1:
The frame structure is segmented into multiple subframes (first subframe, second subframe, third subframe) with different configurations. The first subframe contains first synchronization signals, the second subframe contains second synchronization signals, and the third subframe contains third synchronization signals. This segmentation allows the system to maintain compatibility with legacy systems while introducing new features for enhanced performance.
Solution Approach 2:
The frame structure employs dynamic configurations where the same subframe can be used for different purposes depending on the transmission mode. The base station can dynamically select which subframes to use for synchronization signal transmission based on the specific communication requirements, allowing flexible adaptation between legacy and narrow band modes.
2Measurement precision
If synchronization signals are transmitted in multiple subframes with different symbol sets, then CP length detection accuracy is improved, but the time required for synchronization increases
Solution Approach 1:
The base station transmits synchronization signals in advance across multiple subframes before the terminal needs to perform CP length detection. The first synchronization signals are transmitted in the first subframe, second synchronization signals in the second subframe, and third synchronization signals in the third subframe, allowing the terminal to accumulate detection data beforehand.
Solution Approach 2:
The terminal performs CP length detection by analyzing the received synchronization signals and provides feedback information about the detected CP length to the base station. This feedback mechanism allows the system to accurately determine the CP length used in the narrow band communication.
3Use of energy by moving object
If narrow band communication uses reduced subcarrier spacing, then energy efficiency is improved, but data rate decreases
Solution Approach 1:
The system applies different subcarrier spacing configurations to different parts of the communication system. The narrow band communication uses reduced subcarrier spacing (1.25 kHz or 2.5 kHz) for control channels and synchronization signals to improve energy efficiency, while data channels can use higher subcarrier spacing to maintain data rates.
Solution Approach 2:
The system compensates for the reduced data rate caused by lower subcarrier spacing by utilizing time diversity through multiple subframes. The transmission of synchronization signals across three different subframes provides temporal redundancy that can be used for robust detection and decoding, effectively compensating for the reduced spectral efficiency.
Data Source
AI summary
The present specification provides a method for transmitting and receiving a synchronization signal by a terminal in a wireless communication system, the method comprising the steps of: receiving broadcast information through a predetermined frame from a base station, wherein the predetermined frame is a frame defined for transmitting and receiving a signal in a narrow band (NB) and includes at least one first subframe; and receiving the synchronization signal from the base station through one or more first subframes on the basis of the received broadcasting information.