W-CDMA System Acquisition Using Pilot Signal Timing Reference
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Solution Overview
Problem
Current wireless communication systems face challenges in minimizing system acquisition time, which is crucial for efficient resource allocation and power reduction in mobile stations, as they require substantial Automatic Frequency Control (AFC) convergence time without a timing reference during system acquisition.
Innovation Solution
A method is introduced where a pilot signal of a non-requested W-CDMA system is used as a timing reference for remaining candidate frequencies during system acquisition, reducing or eliminating the need for initial AFC window time, thereby accelerating the system acquisition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a mobile station performs system acquisition scan over multiple candidate frequencies without a timing reference, then it can search for the requested system, but the Automatic Frequency Control convergence time significantly increases system acquisition time
Solution Approach 1:
The patent applies preliminary action by detecting a pilot signal from a non-requested system before completing the acquisition of the requested system. This pilot signal detection happens during the initial frequency scan phase, establishing a timing reference in advance that will be used subsequently for AFC convergence on remaining frequencies, thereby reducing the overall acquisition time while maintaining frequency control accuracy
Solution Approach 2:
The patent uses an intermediary approach by employing a pilot signal from a non-requested system as a temporary timing reference. This intermediary reference signal facilitates the AFC convergence process on other candidate frequencies without requiring the mobile station to have already acquired the requested system, thus accelerating the overall system acquisition process
Data Source
AI summary
In one illustrative example, a system acquisition method suitable for use in W-CDMA utilizes a receiver having an automatic frequency control (AFC) circuit. A system acquisition scan is performed over a plurality of candidate frequencies in an RF band. During the system acquisition scan, a pilot signal of a system on one of the candidate frequencies is detected. When information of the system is successfully decoded, and the system is different from a requested system (e.g. not the RPLMN or HPLMN), the pilot signal of the system is assigned as a timing reference in the receiver for one or more remaining candidate frequencies of the system acquisition scan. Therefore, an AFC window time otherwise needed to converge on a remaining candidate frequency is not needed or reduced.