5G NR Cell Search Using Reduced Synchronization Signal Space
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Solution Overview
Problem
Existing 5G NR networks require inefficient and power-consuming exhaustive 2D searches for synchronization signal blocks, leading to prolonged scanning times and rapid battery drain in user terminals.
Innovation Solution
A two-stage synchronization process is implemented, where user terminals first establish a reduced search space and identify candidate locations for synchronization signals, followed by a validation search in these identified locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaustive 2D search is performed for synchronization signal blocks, then complete coverage of search space is achieved, but scanning time increases and power consumption increases
Solution Approach 1:
The patent segments the exhaustive 2D search space into multiple 1D search spaces by dividing the frequency range into multiple bands. This segmentation allows the terminal to search for synchronization signal blocks in a more efficient manner, reducing the overall scanning time while maintaining detection reliability through systematic coverage of all frequency bands.
Solution Approach 2:
The patent applies preliminary action by first determining the subcarrier spacing before conducting the actual synchronization signal block search. This preliminary determination of key parameters enables the terminal to optimize its search strategy and reduces the time required for the subsequent exhaustive search, as the search can be tailored to the specific subcarrier spacing of the target cell.
2Reliability
If exhaustive 2D search is performed for synchronization signal blocks, then complete coverage of search space is achieved, but power consumption increases
Solution Approach 1:
By segmenting the 2D search space into multiple 1D search spaces based on frequency bands, the patent reduces the computational burden and power consumption associated with processing a large unified search space. The terminal can process smaller segments sequentially, reducing peak power consumption while ensuring complete coverage through systematic exploration of all bands.
Solution Approach 2:
The preliminary determination of subcarrier spacing enables the terminal to optimize its search algorithm and resource allocation before the actual search begins. This allows for more efficient use of processing power during the search, reducing unnecessary computations and thereby lowering power consumption while maintaining detection reliability.
3Loss of time
If reduced search space is used, then scanning time decreases and power consumption decreases, but search area is reduced
Solution Approach 1:
The patent resolves this contradiction by segmenting the reduced search space into multiple frequency bands, ensuring that while each individual search space is smaller and faster to search, the union of all segmented spaces covers the complete original search area. This systematic segmentation maintains comprehensive coverage while enabling faster individual searches.
Solution Approach 2:
By preliminarily determining the subcarrier spacing, the patent enables the terminal to calculate and establish an optimized reduced search space that is tailored to the specific cell characteristics. This preliminary optimization ensures that the reduced search space is sufficiently small to reduce scanning time, yet sufficiently large to maintain complete coverage of possible synchronization signal block locations.
Data Source
AI summary
An apparatus includes a transceiver configured to receive a broadcast signal. The apparatus also includes at least one processor configured to search for a synchronization signal within the broadcast signal. To search for the synchronization signal, the at least one processor is configured to (i) during a first stage, establish a reduced search space and identify one or more locations for the synchronization signal in the reduced search space and (ii) during a second stage, search for the synchronization signal in the one or more identified locations.