Small Cell Access Point Inter-Frequency Neighbor Detection
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Solution Overview
Problem
In wireless communication systems, small cell Access Points often struggle to compile accurate neighbor cell lists, leading to increased risks of call drops at cell edges due to incomplete or missing inter-frequency neighbor cells, especially when the network listen module fails to detect neighboring cells or when intra-frequency handover is disabled.
Innovation Solution
A method where the network element allocates a set of operating frequencies, selects and transmits instructions to User Equipment to send measurement reports on these frequencies, and stores the reports to compile a comprehensive neighbor cell list, even if the network listen module cannot detect inter-frequency neighbors, allowing for dynamic frequency switching to discover new neighbors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the network listen module is used to detect neighboring cells, then the Access Point can automatically configure neighbor cell lists, but inter-frequency neighbor cells may be missed leading to incomplete lists
Solution Approach 1:
The patent introduces User Equipment (UE) as an intermediary to detect and report neighbor cells to the Access Point. The UE measures and reports both intra-frequency and inter-frequency neighbor cells, complementing the network listen module's capabilities and ensuring complete neighbor cell list configuration.
Solution Approach 2:
The patent makes the Access Point capable of operating on multiple frequencies by dynamically switching between them. This multi-functionality allows the AP to directly detect both intra-frequency and inter-frequency neighbor cells, eliminating the limitation of the network listen module.
2Reliability
If the Access Point operates on a single frequency, then it provides stable service, but it cannot detect inter-frequency neighbor cells
Solution Approach 1:
The patent implements dynamic frequency switching in the Access Point, allowing it to change operating frequencies based on service requirements and neighbor cell detection needs. This dynamic behavior enables the AP to maintain stable service on one frequency while periodically switching to detect inter-frequency neighbors.
Solution Approach 2:
The patent employs periodic frequency switching where the Access Point alternates between serving users on a primary frequency and switching to secondary frequencies for neighbor cell detection. This periodic action ensures both continuous service and comprehensive neighbor detection.
3Loss of information
If the Access Point switches frequencies dynamically, then it can discover more neighbor cells, but it may cause service interruption
Solution Approach 1:
The patent applies partial frequency switching where the Access Point switches frequencies only for the minimum necessary duration to detect neighbor cells. By limiting the switching duration and using brief measurement intervals, the system achieves comprehensive detection while minimizing service interruption.
Data Source
AI summary
An Access Point (105) serving a small cell (202) in a cellular communication system (100) uses the User Equipment intra-frequency Primary Scrambling Code detection mode to detect neighbors inter-frequency by switching its carrier frequency to a frequency on which it is desired to check for neighbors (for a period long enough and/or often enough for it UE to have a reasonable chance of detecting such a neighbor). Received measurements on such neighbor cells (202, 203) may be used to compile a neighbor cell list if no such list has been preconfigured in the Access Point or if network listen results have provided only a limited number of detected neighbor cells.