Wireless Preamble Structure for Robust Time-Frequency Synchronization
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Solution Overview
Problem
Conventional wireless communication preambles face challenges in enhancing automatic gain control, signal detection, and time and frequency synchronization performances, leading to increased complexity and peak-to-average-power ratio (PAPR), and constraints on synchronization estimation performance.
Innovation Solution
A method and apparatus for generating a frame that includes a modified sequence using a first base sequence for synchronization estimation, assigning it and its complex conjugate or sign-different sequence to the frequency domain, and incorporating a TD sequence for automatic gain control and signal detection, along with NRP/RP sequences for robust synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional preambles use single cyclic prefix and four repetition pattern sequences, then the preamble structure is simple, but automatic gain control, signal detection, and synchronization performance are insufficient
Solution Approach 1:
The preamble is segmented into multiple OFDM symbols (first and second OFDM symbols), each containing different sequences. The first OFDM symbol includes a first sequence and its complex conjugate, while the second OFDM symbol includes a second sequence and its complex conjugate. This segmentation allows independent optimization of different sequence properties for better synchronization and signal detection performance.
Solution Approach 2:
The patent employs composite sequence structures combining multiple sequence types (first sequence, complex conjugate of first sequence, second sequence, complex conjugate of second sequence) within the preamble. These composite structures leverage the complementary properties of different sequences to enhance both automatic gain control and synchronization performance simultaneously.
2Reliability
If conventional preambles use repetition pattern sequences, then the implementation is straightforward, but peak-to-average-power ratio increases and complexity increases
Solution Approach 1:
The patent uses complex conjugate sequences instead of simple repetition patterns. By inverting the approach from repeating the same sequence to using complex conjugates, the patent achieves better correlation properties for signal detection while reducing the peak-to-average-power ratio. The complex conjugate relationship provides mathematical properties that simplify reception processing.
Solution Approach 2:
The patent changes the sequence parameters by using complex conjugates rather than identical repetitions. This parameter change transforms the autocorrelation and cross-correlation properties of the preamble sequences, leading to improved signal detection performance and reduced peak-to-average-power ratio without increasing reception complexity.
3Measurement precision
If conventional preambles include two OFDM symbols with repetition patterns, then signal detection is possible, but time and frequency synchronization estimation performance is constrained
Solution Approach 1:
The preamble structure is designed to serve multiple functions simultaneously: the first and second sequences and their complex conjugates work together to provide both time synchronization and frequency synchronization estimation. The multi-functional design allows a single preamble structure to achieve precise synchronization in both time and frequency domains without requiring separate synchronization mechanisms.
Data Source
AI summary
Disclosed is a technique related to a method and apparatus for generating a preamble and a data frame for wireless communication, and to a synchronization estimation method using the preamble. According to the technique, a method for generating a frame for wireless communication is disclosed, wherein the method comprises: a step of generating a modified sequence using a first base sequence for synchronization estimation; and a step of allocating the first base sequence and the modified sequence to the frequency domain of a first timeslot to generate a preamble. The modified sequence includes a complex conjugated sequence of the first base sequence or a sequence having a code different from that of the first base sequence.