AGC Preamble Sequence Design for D2D Signal Stability
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Solution Overview
Problem
In device-to-device (D2D) communication, existing wireless communication systems lack an efficient method for generating and transmitting an automatic gain control (AGC) preamble, which is crucial for stabilizing signal power and reducing interference, especially in scenarios with varying frequency bandwidths and network coverage.
Innovation Solution
A method involving a user equipment (UE) that maps an AGC preamble sequence to a resource element and performs an inverse fast Fourier transform (IFFT), with the sequence repeated N times, where N is proportional to the frequency bandwidth for in-coverage UEs, and optionally linked to the synchronization source and demodulation reference signal, to generate and transmit an AGC preamble.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an AGC preamble is transmitted in D2D communication, then signal power stability is improved, but resource overhead increases
Solution Approach 1:
The AGC preamble sequence is designed to serve dual purposes: it performs automatic gain control function for signal power stabilization and simultaneously acts as a reference signal for data demodulation. This multi-functionality reduces resource overhead by eliminating the need for separate reference signals while maintaining signal power stability.
Solution Approach 2:
The patent combines the AGC preamble function with the demodulation reference signal function into a single transmitted sequence. By merging these two functions into one signal element, the system reduces the quantity of transmitted resources while achieving both power stabilization and demodulation requirements.
2Adaptability or versatility
If the AGC preamble sequence is repeated N times proportional to frequency bandwidth, then adaptability to different bandwidths is improved, but signal complexity increases
Solution Approach 1:
The repetition factor N is dynamically adjusted based on the system frequency bandwidth. For larger bandwidths, N is increased to maintain adequate signal characteristics, while for smaller bandwidths, N is reduced. This dynamic adaptation allows the same basic sequence structure to work across different bandwidth configurations without requiring completely different signal designs.
Solution Approach 2:
The AGC preamble sequence is segmented into N repeated instances across the frequency bandwidth. Each segment carries the same base sequence but is distributed across different frequency resources. This segmentation approach enables scalable deployment across different bandwidths by simply changing the repetition count rather than redesigning the entire sequence structure.
3Productivity
If the AGC preamble is used for data demodulation, then resource efficiency is improved, but measurement precision for AGC may be reduced
Solution Approach 1:
Different portions of the repeated AGC preamble sequence are utilized for different purposes. Specific instances of the repeated sequence are designated for AGC measurement while others serve as demodulation references. This local differentiation allows both functions to operate simultaneously with adequate precision by allocating appropriate signal instances to each function based on their specific requirements.
Data Source
AI summary
A method of generating a device-to-device (D2D) signal by a user equipment (UE) in a wireless communication system, the method includes mapping a sequence for an automatic gain control (AGC) preamble to a resource element; and generating the AGC preamble by performing an inverse fast Fourier transform (IFFT) on the sequence for the AGC preamble mapped to the resource element, further the sequence for the AGC preamble is repeated N times when mapped to the resource element, and also N is determined based on at least one of a system frequency bandwidth or a transmission frequency bandwidth.