Narrowband LTE Cell Search Using Repetitive Synchronization Signals

The patent applies preliminary action by transmitting multiple occurrences of synchronization signals (PSS and SSS) before the actual cell search procedure. These preliminary transmissions include reference signals and synchronization sequences that are sent in advance to establish initial timing and frequency references, enabling the device to perform correlation operations more efficiently and reduce the overall synchronization time while improving accuracy in weak signal conditions

The patent uses copying by creating multiple copies of the synchronization signals (PSS and SSS) and transmitting them at different time instances and positions. The device can correlate received signals with these known copies to detect cell presence, determine timing, and identify cell IDs. Multiple copies allow the device to accumulate signal energy and perform more reliable detection, reducing synchronization time and eliminating phantom cell effects

The patent applies segmentation by dividing the cell search procedure into distinct stages: initial synchronization signal detection, timing acquisition, frequency offset correction, and cell ID identification. Each stage processes specific signal components (PSS for timing and basic sync, SSS for cell ID group identification) separately, allowing the device to accumulate evidence progressively without requiring complex simultaneous processing of all signals, thus improving accuracy while managing complexity

The patent uses intermediary elements such as reference signals and preamble sequences that mediate between the transmitted synchronization signals and the device's detection algorithms. These intermediaries provide known patterns that simplify correlation operations, enable efficient signal processing through matched filtering, and reduce computational complexity while maintaining high detection accuracy through structured signal designs

The patent applies periodic action by transmitting synchronization signals (PSS and SSS) at regular periodic intervals within the frame structure. The signals are transmitted in specific subframes (e.g., subframes 0 and 5) with defined periodicity, allowing devices to predict signal locations, accumulate energy over multiple periods, and achieve reliable timing synchronization. This periodic transmission pattern reduces overall overhead compared to continuous transmission while maintaining robust detection capability through repeated observations

The patent achieves multi-functionality by designing the synchronization signal structure to simultaneously perform multiple functions: PSS provides both timing synchronization and basic cell identification, while SSS provides cell ID group identification and frame timing information. The same signal structures serve both synchronization and measurement purposes, reducing the need for separate dedicated signals and minimizing overall overhead while maintaining reliable timing and cell detection