DTMF Error Correction for Mobile Uplink Control
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Solution Overview
Problem
Existing voice telephony systems on mobile devices face challenges in detecting and transmitting cancel transfer codes using DTMF tones, especially under poor wireless conditions where DTMF digits may be lost during transmission.
Innovation Solution
A computer-implemented method that allows mobile devices to receive commands during an in-progress call over a voice channel, enabling uplink control in mobile device telephony by sending a verification code as audible tones when identifying information is unavailable, and employing state-dependent DTMF code translation to ensure successful call control and status updates even without a data channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DTMF tones are transmitted over the speech path for call control, then call control functions can be performed without a data channel, but DTMF digits may be lost during transmission under poor wireless conditions
Solution Approach 1:
The system performs preliminary actions by sending verification codes (audible tones) before attempting to send the actual cancel transfer code. This allows the receiving end to prepare for expected DTMF sequences and improve detection reliability even when digits may be lost during transmission
Solution Approach 2:
The system implements feedback mechanisms where the receiving end sends acknowledgments and status updates back to the mobile device. This feedback loop allows for verification of received DTMF codes and enables retransmission or correction if digits were lost, thereby improving overall transmission reliability
2Adaptability or versatility
If verification codes are sent as audible tones when identifying information is unavailable, then call verification can proceed without data channel, but additional time is required for tone transmission and verification
Solution Approach 1:
The system merges the verification process with the existing call setup流程 by utilizing the voice channel that is already established for the call. Instead of separate verification steps, the audible tones are integrated into the call flow, reducing overall time consumption while maintaining verification capability
3Measurement precision
If state-dependent DTMF code translation is implemented, then call control accuracy is improved, but system complexity increases
Solution Approach 1:
The system changes parameters by translating DTMF codes based on the current call state. Instead of using fixed DTMF code mappings, the translation varies according to the call state (e.g., different states require different code interpretations), thereby improving detection accuracy while managing complexity through state-based logic
Data Source
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AI summary
Aspects relate to provision of enterprise call capabilities to mobile devices. For example, a mobile device can indicate, over a data channel, that a PBX is to make a call on its behalf to a called party. The PBX can call back the mobile device, call the called party, and bridge those call legs to establish the call. The mobile device can employ mechanisms that a particular incoming call is made by the PBX. These mechanisms can include using ANI information, sending, and receiving audible verification codes over the voice channel established after answering the incoming call. The verification codes can be selected based different behaviors of the mobile devices. Pattern recognition algorithms are applied to the received DTMF codes in order to increase the system's resilience to transmission errors.