CDMA Call Prompt Tone Elimination via Downlink Signal Extraction
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Solution Overview
Problem
In CDMA communications, users experience interference when an unconnected call initiated by one mobile phone affects an ongoing call between another pair of mobile phones, leading to persistent prompt tones and incorrect call interface displays.
Innovation Solution
A method that detects and eliminates prompt tones by analyzing downlink signals, allowing mobile phones to continue outputting call voices while stopping prompt tones when a call is rejected or abandoned, and updating the call interface accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the mobile phone A continues to output the prompt tone after rejecting the call from mobile phone C, then the call interface can indicate the incoming call status, but the prompt tone causes interference to the ongoing call between mobile phone A and mobile phone B
Solution Approach 1:
The patent extracts and removes the prompt tone from the downlink signal after the incoming call is rejected. The terminal detects the prompt tone in the downlink signal, and when it determines that the incoming call has been rejected, it stops outputting the prompt tone while continuing to maintain the call interface display. This separates the call status indication function from the prompt tone output, eliminating interference to the ongoing call.
2Loss of information
If the mobile phone A displays the call interface indicating an incoming call from mobile phone C, then the user can see the call status, but the call interface persists even after the incoming call is abandoned, causing confusion
Solution Approach 1:
The patent implements feedback mechanisms where the terminal continuously monitors the downlink signal for prompt tones and detects whether the incoming call is still active. When the terminal detects that the prompt tone disappears (indicating the incoming call has been abandoned), it automatically updates the call interface to reflect the current call status. This feedback loop ensures the display accurately represents the actual call state, preventing user confusion.
3Measurement precision
If the mobile phone A detects the prompt tone continuously, then the incoming call status can be monitored, but the prompt tone persists in the downlink signal causing ongoing interference
Solution Approach 1:
The patent extracts the prompt tone component from the downlink signal through detection and identification. The terminal analyzes the downlink signal to identify the presence of prompt tones, and once the incoming call is determined to be rejected or abandoned, it removes the prompt tone output while maintaining the ability to detect call status changes. This extraction process eliminates the harmful interference while preserving detection precision.
Data Source
AI summary
A call prompt methods and terminals. One example method includes displaying a first interface on a display screen of a first terminal, showing that the first terminal is in a call with a second terminal via a CDMA communication network, while the first terminal is in the call with the second terminal, displaying a second interface on the display screen that prompts that a third terminal is initiating a call to the first terminal. Outputting a sound that includes a prompt tone and a call voice between the first terminal and the second terminal, the prompt tone that the third terminal is initiating a call to the first terminal, and when the call initiated by the third terminal is rejected by the first terminal's user, continuing output the call voice between the first terminal and the second terminal, and stopping output the prompt tone.