Cell Identifier Detection via Synchronization Sequence Temporal Location
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Solution Overview
Problem
Mobile communications systems face challenges in providing reliable coverage to devices in remote or difficult radio reception environments, particularly for low-cost, reduced-sensitivity receivers used in machine-type communication applications, where detecting cell identifiers is difficult, leading to increased acquisition time and reduced coverage area.
Innovation Solution
A communications device is configured to detect synchronization sequences at varying temporal locations within frames, allowing it to estimate cell identifiers more accurately and reduce the probability of missed detection, thereby extending the coverage area and improving acquisition times by restricting the search for correct cell identifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-cost receiver with reduced sensitivity is used in MTC devices, then device cost is reduced, but detection probability of cell identifiers decreases
Solution Approach 1:
The cell identifier detection process is segmented into two stages: first detecting the synchronization sequence to identify a subset of possible cell identifiers, then searching only within that restricted subset. This segmentation allows low-cost receivers to achieve reliable detection by dividing the search space into manageable portions rather than searching all possible cell identifiers simultaneously.
Solution Approach 2:
The synchronization sequence detection is performed as a preliminary action before the actual cell identifier search. By first detecting the synchronization sequence and its temporal location, the system pre-restricts the search space to a specific subset of cell identifiers, making the subsequent detection process more reliable for low-sensitivity receivers.
2Area of stationary object
If the coverage area is extended to remote locations, then service availability improves, but acquisition time increases
Solution Approach 1:
The cell identifier search space is segmented into multiple subsets, each associated with different temporal locations of synchronization sequences. Devices in remote areas can restrict their search to relevant subsets based on detected synchronization sequence positions, significantly reducing acquisition time while maintaining extended coverage capability.
Solution Approach 2:
The system changes the parameter of search space size dynamically. By using the temporal location of synchronization sequences to restrict the cell identifier search to specific subsets, the effective search space parameter is reduced, enabling faster acquisition even in extended coverage areas where signal strength is weak.
3Ease of manufacture
If the receiver sensitivity is reduced to lower device cost, then manufacturing ease improves, but the probability of missed detection increases
Solution Approach 1:
The synchronization sequence detection serves as a preliminary filtering action that identifies which subset of cell identifiers are relevant. This preliminary step allows low-sensitivity receivers to focus their detection efforts on a restricted set of candidates, improving detection accuracy without requiring high receiver sensitivity.
Solution Approach 2:
The synchronization sequence acts as an intermediary that mediates between the received signal and the cell identifier detection. By first detecting the synchronization sequence and using its temporal location to identify a subset, the system creates an intermediate step that enhances detection accuracy for low-cost receivers with reduced sensitivity.
Data Source
AI summary
A communications device transmits/receives data from a mobile communications network including one or more network elements forming plural cells. Each cell is allocated a cell identifier. For each cell the network elements provide a wireless access interface providing plural communications resource elements across a frequency range of a first carrier, and divided in time into plural frames. The one or more network elements transmit in one or more of the frames a synchronization sequence, each synchronization sequence providing an indication of a cell identifier. A controller calculates an estimate of a cell identifier from the detected synchronization sequence, and uses the cell identifier to transmit/receive the data to/from the mobile communications network via the wireless access interface. A relative temporal location of the synchronization sequence within the frame provides the communications device with an indication of the cell identifier of the cell.