RF Carrier Bandwidth Screening for Faster GSM Band Scanning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current mobile station scanning methods in wireless communication networks, particularly in the 850 MHz band, are inefficient due to the need for a long time to reject non-GSM RF signals, which can be stronger than GSM signals, and fail to quickly identify valid GSM RF carrier signals, making it difficult to achieve network acquisition within the required five seconds.
Innovation Solution
A method that involves monitoring RF channels to estimate the bandwidth of candidate RF carrier signals and using a system signal detection process like FCCH detection to quickly identify valid GSM signals by distinguishing between GSM and non-GSM bandwidths, thereby reducing the time required to scan the RF band and construct a channel list.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the FCCH detector is used to reject non-GSM RF signals, then the reliability of signal identification is improved, but the scanning time increases significantly (50.8 milliseconds per signal)
Solution Approach 1:
The patent applies preliminary action by performing bandwidth estimation on candidate RF carrier signals before attempting FCCH detection. The bandwidth estimator quickly identifies and filters out non-GSM signals based on their incorrect bandwidth characteristics, so that the time-consuming FCCH detector only needs to process pre-validated GSM signals. This preliminary filtering step significantly reduces the overall scanning time while maintaining reliable signal identification.
2Reliability
If the mobile station scans all RF channels in the 850 MHz band to construct a channel list, then the completeness of network detection is improved, but the time required to achieve network acquisition exceeds the five-second requirement
Solution Approach 1:
The patent applies segmentation by dividing the signal validation process into two distinct segments: (1) a quick bandwidth estimation segment that filters out obviously non-GSM signals, and (2) a more thorough FCCH detection segment that validates remaining candidates. This segmented approach allows the system to maintain complete network detection by thoroughly checking all GSM-compatible signals while rapidly dismissing non-GSM interferers, thereby achieving network acquisition within the five-second requirement.
Solution Approach 2:
The patent applies preliminary action by performing bandwidth estimation as a preliminary filtering step before the main FCCH detection process. By quickly identifying and eliminating non-GSM signals based on bandwidth characteristics, the system reduces the number of signals that require time-consuming FCCH detection, thus enabling complete network detection within the five-second acquisition time requirement.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
One illustrative method of scanning a radio frequency (RF) band (e.g. 850 MHz band) for valid RF carrier signals of a wireless communication network (e.g. a GSM network) includes the steps of monitoring an RF channel to receive a candidate RF carrier signal; identifying whether the candidate RF carrier signal is a valid RF carrier signal of the wireless communication network by estimating a bandwidth of the candidate RF carrier signal and, if the estimated bandwidth is different from a predetermined bandwidth associated with valid RF carrier signals of the wireless communication network, identifying that the candidate RF signal is not a valid RF carrier signal of the wireless communication network; and repeating the acts of monitoring and identifying for a next RF channel of a plurality of RF channels associated with the wireless communication network. Preferably, the RF bandwidth estimation is performed together with a system signal detection process (e.g. FCCH detection). Advantageously, the time required to scan the RF band is reduced.