OFDMA Synchronization Channel Signal Interleaving for Acquisition Time Reduction
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Solution Overview
Problem
In orthogonal frequency division multiple access (OFDMA) wireless communication systems, the complexity of synchronization channel signals increases with the number of cells and system design, making initial acquisition and cell search time-consuming and inefficient.
Innovation Solution
The method involves transmitting an OFDMA signal with a synchronization channel signal that has predetermined time domain symmetry, distributed among subcarriers and symbol periods, allowing for improved cell identification and reduced acquisition time by using sequence elements like generalized chirp-like sequences, which are optimally cross-correlated for unique cell identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the synchronization channel signal includes more cells and system information, then the system capacity and information completeness improve, but the signal length and complexity increase, making acquisition and cell search more time-consuming
Solution Approach 1:
The synchronization channel signal is segmented into multiple sequence elements that are distributed across different subcarriers and time intervals. This segmentation allows the receiver to process and identify cell information in a structured manner, reducing the overall acquisition time while maintaining the ability to support multiple cells
Solution Approach 2:
The patent distributes sequence elements across both frequency (subcarriers) and time (symbol periods) dimensions. This two-dimensional distribution enables parallel processing of cell information from multiple cells simultaneously, reducing acquisition time while maintaining system capacity
2Quantity of substance
If the synchronization channel signal includes more cells and system information, then the system capacity and information completeness improve, but the signal complexity increases
Solution Approach 1:
The complex synchronization channel signal is divided into multiple sequence elements distributed across subcarriers and time intervals. This segmentation simplifies the processing complexity by breaking down the overall signal into manageable components that can be processed independently and then combined
Solution Approach 2:
The patent uses a predefined number of sequence elements (e.g., 7 sequence elements) that provides sufficient information for cell identification without excessive complexity. This partial action approach achieves the necessary system capacity while avoiding unnecessary signal complexity
3Measurement precision
If sequence elements are distributed among subcarriers and symbol periods, then the time domain symmetry is maintained and cell identification is improved, but the signal distribution complexity increases
Solution Approach 1:
Different sequence elements are assigned to different subcarriers and time intervals with specific local properties. This local quality assignment maintains the overall time domain symmetry while enabling precise cell identification through the unique characteristics of each distributed sequence element
Solution Approach 2:
The distributed sequence elements serve multiple functions simultaneously: they maintain time domain symmetry, enable cell identification, and support multiple cells. This multi-functionality reduces the need for separate signaling mechanisms, thereby managing distribution complexity efficiently
Data Source
AI summary
A method and apparatus is provided for transmitting an orthogonal frequency domain multiple access (OFDMA) signal including a synchronization channel signal transmitted including a plurality of sequence elements interleaved in time and frequency. The synchronization channel signal sequence elements enable an initial acquisition and cell search method with low computational load by providing predetermined time domain symmetry for common sequence elements in OFDMA symbol periods for OFDMA symbol timing detection and frequency error detection in an OFDMA system supporting multiple system bandwidths, both synchronized and un-synchronized systems, a large cell index and an OFDMA symbol structure with both short and long cyclic prefix length.