Synchronization Signal Slot Allocation for Neighbor Cell Search
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mobile communication systems, the neighbor cell search is hindered when the signal power of the serving cell acts as very large interference, leading to difficulties in handover and potential communication quality deterioration.
Innovation Solution
A method and apparatus for transmitting a synchronization signal that determines the number of slots for synchronization signal transmission based on the number of neighbor cells, allocates a synchronization signal region in the first slot, and reserves other slots for no transmission, using modular arithmetic on the cell identifier and number of neighbor cells to optimize signal allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal performs neighbor cell search using general synchronization methods, then the neighbor cell can be detected under normal SINR conditions (−6 to −3 dB), but the search fails when the serving cell signal power is very large causing high interference
Solution Approach 1:
The patent segments the synchronization signal transmission into multiple slots within a period. By dividing the transmission resources, the terminal can selectively process signals from different slots, enabling it to identify and utilize slots with lower interference from the serving cell, thus improving neighbor cell detection reliability under high interference conditions
Solution Approach 2:
The patent introduces a time-domain dimension by allocating synchronization signals to different slots. This allows the terminal to search for neighbor cells across multiple time instances, increasing the probability of finding slots where the serving cell interference is reduced, thereby overcoming the limitation of single-time-point detection
2Object-affected harmful factors
If the terminal waits for serving cell signal power to decrease before searching for neighbor cells, then interference is reduced, but communication quality deteriorates and handover may fail
Solution Approach 1:
The patent enables the terminal to perform preliminary neighbor cell search and measurement activities during periods when serving cell signal is strong, by utilizing multiple slot opportunities. This preliminary action allows the terminal to identify suitable neighbor cells before the serving cell signal deteriorates, ensuring timely handover execution and maintaining communication reliability
3Area of stationary object
If the synchronization signal is transmitted in all slots, then coverage is maximized, but interference to neighbor cell search increases when serving cell signal is strong
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different slots. Instead of uniform transmission, the system allows flexible allocation where certain slots can be designated for synchronization signal transmission while others may be adjusted or reserved, enabling localized optimization to reduce interference in specific time instances while maintaining overall coverage
Data Source
AI summary
A base station in a mobile communication system determines the number of slots that are to be used to transmit a synchronization signal in a period of the synchronization signal depending on the number of neighbor cells, allocates a synchronization signal region in which the synchronization signal is to be transmitted to a first slot of the determined number of slots depending on a cell identifier of a serving cell, and allocates a reserved region in which no signal is transmitted to slots other than the first slot among the determined number of slots so as to correspond to a position of the synchronization signal region.