PSS Symbol Division for CFO Robustness
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Solution Overview
Problem
In wireless communication systems, particularly in the next generation 5G NewRAT, the existing synchronization signal designs face challenges with timing ambiguity due to Carrier Frequency Offset (CFO) and increased detection complexity, which affect the accuracy and efficiency of synchronization signal detection.
Innovation Solution
A method for transmitting a Primary Synchronization Signal (PSS) by dividing a single symbol into multiple durations and generating sequences that are mapped to these durations, using conjugate complex relations and DFT spreading, to reduce timing ambiguity and detection complexity, while maintaining robustness against CFO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single synchronization signal sequence is transmitted in one symbol, then the transmission structure is simple, but timing ambiguity occurs due to Carrier Frequency Offset
Solution Approach 1:
The single synchronization signal symbol is divided into multiple durations (e.g., 4 durations), and different sequences are transmitted in each duration. This segmentation allows the receiver to detect timing more accurately by identifying which duration contains the valid sequence, thereby resolving timing ambiguity caused by CFO while maintaining a relatively simple overall transmission structure.
2Measurement precision
If multiple sequences are generated and mapped to multiple durations, then timing ambiguity is reduced, but detection complexity increases
Solution Approach 1:
The patent employs asymmetric sequence design where odd sequences use one base sequence and even sequences use another base sequence (with conjugate complex relation). This asymmetric structure enables the receiver to reduce detection complexity by only needing to correlate with two base sequences rather than multiple independent sequences, while still maintaining the ability to resolve timing ambiguity across the four durations.
3Device complexity
If sequences are mapped to subcarriers with same spacing, then frequency domain structure is simplified, but robustness against CFO decreases
Solution Approach 1:
The patent maps sequences to subcarriers with the same spacing in the frequency domain, but introduces robustness against CFO by utilizing the time domain dimension through multiple durations. Each duration contains a sequence that is robust to CFO, and the time-domain separation of durations allows the receiver to identify the correct timing even in the presence of frequency offset, thus achieving CFO robustness without complicating the frequency domain structure.
Data Source
AI summary
Disclosed is a method for transmitting a primary synchronization signal (PSS) by a base station in a wireless communication system. In particular, the method may comprise the steps of: dividing one symbol into multiple periods; generating multiple sequences for the PSS, the number of which is identical to the number of the multiple periods; and mapping the multiple sequences to the one symbol divided into the multiple periods, and transmitting the multiple sequences.