Method for avoiding communication collisions between co-existing plc systems on using a physical transmission medium common to all plc systems and arrangement for carrying out said method
First Claim
1. Method for avoiding communication collisions between co-existing PLC systems on using physical transmission medium common to all PLC systems, the method steps of which include the determination of an average noise level (G) on the physical transmission medium and the classification of the physical transmission medium as busy or free depending on whether a specified threshold value (S) for the noise level is overshot or undershot by the determined average noise level (G), characterized in that the threshold value (e.g. S1) for the noise level is varyingly determined depending on changes over time in the determined average noise level (G) in parallel and integrally at least one single time with a respective assigned time constant (e.g. T1) and such an amplification factor assigned in each case, that in the steady state and in a situation in which a noise level is exclusively present the determined varying threshold value (e.g. S1) is greater than the determined average noise level (G), that the varying threshold values (e.g. S1 up to Sn) determined in this way in each case are each compared with the determined average noise level (G) and an active signal is generated in each case depending on the results of the particular comparison, if the comparison shows that the determined average noise level (G) is greater than the varying threshold value (e.g. S1) in comparison with it in each case, and that in a logic element that takes account of the actual significance of the particular individual determined active signal all the determined active signals are used to generate an overall decision signal for indication of the busy or not busy state of the physical transmission medium.
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Abstract
Method for avoiding communication collisions between co-existing PLC systems on using a physical transmission medium common to all PLC systems and arrangement for carrying out said method
An improved method for avoiding communication collisions between co-existing PLC systems on using a physical transmission medium common to all PLC systems and arrangement for carrying out said method with regard to the reliability of the overall result are disclosed, the main principle of which is that the decision of whether or not a physical transmission line is active or not is based on a mean noise level (G) and at least one single threshold value (e.g. S1) which matches the level of interference occurring in the physical transmission channel. In a further improvement several such threshold values (S1 to Sn) are provided, which are combined to give an overall decision signal by means of a corresponding logical combination circuit. The individual, intermediate determined threshold value decisions can have a priority assigned by the logical connection circuit.
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Citations
6 Claims
- 1. Method for avoiding communication collisions between co-existing PLC systems on using physical transmission medium common to all PLC systems, the method steps of which include the determination of an average noise level (G) on the physical transmission medium and the classification of the physical transmission medium as busy or free depending on whether a specified threshold value (S) for the noise level is overshot or undershot by the determined average noise level (G), characterized in that the threshold value (e.g. S1) for the noise level is varyingly determined depending on changes over time in the determined average noise level (G) in parallel and integrally at least one single time with a respective assigned time constant (e.g. T1) and such an amplification factor assigned in each case, that in the steady state and in a situation in which a noise level is exclusively present the determined varying threshold value (e.g. S1) is greater than the determined average noise level (G), that the varying threshold values (e.g. S1 up to Sn) determined in this way in each case are each compared with the determined average noise level (G) and an active signal is generated in each case depending on the results of the particular comparison, if the comparison shows that the determined average noise level (G) is greater than the varying threshold value (e.g. S1) in comparison with it in each case, and that in a logic element that takes account of the actual significance of the particular individual determined active signal all the determined active signals are used to generate an overall decision signal for indication of the busy or not busy state of the physical transmission medium.
Specification