Virtual Time Counter for Communication Unit Synchronization
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Solution Overview
Problem
In wireless communication networks, particularly with flowmeters, internal time shifts between transmitters and receivers cause difficulties in encryption and decryption due to differing internal times, leading to unsuccessful decryption and increased battery consumption, especially when high transmission rates are required.
Innovation Solution
A method for adjusting a shifted time in communication units by using a virtual internal time as a counter variable in a changing mode, separate from the actual internal time for cryptographic operations, allowing synchronization without extending telegram length or reducing transmission frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal time is used directly for cryptographic operations, then the encryption and decryption process is simple, but decryption fails when time shifts occur between transmitter and receiver
Solution Approach 1:
The internal time is segmented into two separate functions: one component tracks real time progression for chronological ordering, while another component serves as a virtual counter for cryptographic operations. This segmentation allows each component to fulfill its specific role without interference from time shifts, ensuring decryption success while maintaining system reliability.
Solution Approach 2:
A virtual time counter is introduced as an intermediary between the actual internal time and the cryptographic operations. This virtual counter increments independently of real time passage and is used exclusively for initialization vectors, mediating the cryptographic process to be immune to time shifts while the real internal time continues to measure actual elapsed time.
2Reliability
If the telegram length is extended to include counter information, then the receiver can recover the initialization vector, but battery consumption and on-air-time increase
Solution Approach 1:
The transmitter and receiver both maintain identical virtual time counters that increment automatically with each encryption/decryption operation. This self-service mechanism ensures both parties generate the same initialization vectors without needing to transmit the counter value, eliminating the need for extended telegrams while maintaining reliability.
3Productivity
If the transmission frequency is increased to reduce waiting time, then data availability improves, but the risk of duplicate initialization vectors increases
Solution Approach 1:
The virtual time counter increments continuously with every encryption operation regardless of real time passage or transmission frequency. This continuous incrementing ensures that each encryption operation receives a unique initialization vector based on the sequence of operations rather than time intervals, allowing high transmission frequencies without risking duplicate vectors.
4Measurement precision
If the internal time is synchronized with external reference time, then time accuracy improves, but time shifts between different communication units persist
Solution Approach 1:
Each communication unit maintains its own local virtual time counter that is independent of external reference times or other units' clocks. This local quality approach ensures that each unit's cryptographic operations rely on its own sequential counter rather than synchronized time, eliminating time shift issues between units while maintaining individual time accuracy for scheduling purposes.
Data Source
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AI summary
The present invention relates to a method for adjusting a shifted time in a communication unit, wherein the communication unit has an internal time and the internal time is used for cryptographic operations, the method comprises following steps: Comparing the actual internal time of the communication unit and an external reference time. Changing from a standard mode into a changing mode if the actual value of the internal time and the external reference time differ about a first time difference value, wherein in the changing mode the internal time is set to the external reference time and changed ongoing in real time, a virtual internal time is used for cryptographic operations, the virtual internal time is changed by a virtual time unit each time data is encrypted and/or encrypted data is sent, the time duration of the virtual time unit being different from the time duration of the associated real time unit.