Modem Mode Switching for Noise Adaptation
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Solution Overview
Problem
Traditional data communication equipment through telephone networks, such as V.34 modems, face reliability issues under abnormal line conditions like noise, requiring complex SNR calculations and mode changes, which are not efficiently addressed by existing solutions.
Innovation Solution
A communication apparatus with a noise information memory and mode memory that selects and changes communication modes based on noise levels, allowing operation in multiple modes like V.34, V.17, and V.27, using a mode change control unit to adapt during line probing and training phases, simplifying the configuration and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If V.34 mode is used for high-speed data transmission, then transmission speed is improved, but communication reliability deteriorates under abnormal line conditions
Solution Approach 1:
The patent implements dynamic mode switching between V.34 and V.17 communication modes based on real-time detection of line conditions. The system transitions from a static single-mode approach to a dynamic multi-mode system that adapts to changing environmental conditions, thereby maintaining both high speed when possible and reliability when needed.
Solution Approach 2:
The patent changes the communication mode parameter (V.34 vs V.17) in response to detected line conditions such as noise levels and signal quality. By monitoring parameters like carrier-to-noise ratio and adjusting the communication mode accordingly, the system optimizes the trade-off between transmission speed and reliability based on actual channel characteristics.
2Reliability
If SNR calculation is performed using AC voltage detection during silence period and protocol signal reception, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the noise detection function with the existing AC voltage detection circuit already present in the modem. Instead of adding a separate dedicated noise detection system, the invention reuses the existing circuitry to detect both signal voltage and noise voltage, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The AC voltage detection circuit is designed to serve multiple functions: detecting signal voltage during protocol signal reception, detecting noise voltage during silence periods, and providing information for communication mode selection. This multi-functional approach allows reliable SNR calculation without requiring dedicated separate circuits for each function.
3Measurement precision
If noise detection is performed during both silence period and protocol signal reception, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs noise voltage detection during silence periods that occur before protocol signal reception. By detecting noise in advance during the silence period, the system prepares the SNR calculation data beforehand, so that when the protocol signal arrives, the measurement can be completed quickly without requiring extended measurement time.
Solution Approach 2:
The system continuously monitors the line condition by detecting noise voltage during silence periods and signal voltage during protocol reception without interrupting the normal communication flow. The measurements are performed continuously in the background during available time slots, maintaining measurement precision while minimizing impact on communication timing.
Data Source
AI summary
The present invention relates to a data communication method and apparatus comprising a noise information memory for storing noise information to indicate a degree of noise on a current communication line and capable of performing communications in a plurality of communication modes. The method and apparatus further comprising a mode memory for storing the plurality of communication modes in response to the degree of noise, and a mode change control unit for reading current noise information from the noise information memory and selecting the communication mode corresponding to the current degree of noise from the mode memory, and changing the current communication mode into the selected communication mode. The present invention provides an apparatus and a method for highly reliable data communication with simplified construction.