This technical report of type 2 describes a lower layer profile that includes the medium access control (MAC) sublayer, the physical signalling (PLS) sublayer and the mains attachment units (MAU), with the purpose of giving a contribution to build up a set of standards for effective communication on MV and LV network for distribution line carrier (DLC) systems.
This profile uses the FSK modulation technique that offers the advantages of low cost implementation, robustness and immunity against noise and interferences. Furthermore, the transmission quality is predictable knowing few parameters of the transmission medium. Using standard electrical signal interface to the modem, the profile is effective for different modulation techniques.
Different technical approaches in developing communication for DLC systems are in progress. As a consequence, at present different low level profiles are feasible with acceptable results in terms of performance and cost-effectiveness. In many cases, the differences amongst solutions are minor and it is possible to find a common root. This report describes a low level profile that assembles some common experience.
According to the structure of the open system interconnection model, the low level profile should present a standard interface to the logical link control (LLC) sublayer and consists of sublayers such as the MAC sublayer, PLS and MAU, that present well-defined interface to each other.
The MAC sublayer here described interfaces both the LLC connectionless (CL) (see IEC 61334-4-32) and the LLC connection oriented (CO) (see IEC 61334-4-33).
The use of the MAC in the two cases is different due to the frame length and the frame sequence on the medium. To improve the efficiency of the communication, different classes of service are given. The proper use of the class of service and related parameters allow users control of the transfer and waiting time of the processes involved in the transmission.