A new rate adjustment algorithm for traffic admissions in smart grid communications

Smart Grid uses the TCP/IP protocol stack for wide area communications. To ensure low latency end to end communications, the FREEDM project chooses UDP datagram as the preferred technique. However, when many devices are using the same network resources, congestion can happen on intermediate routers. Unlike TCP, which uses ECN as an approach for congestion control, UDP does not have a similar implementation in RFC. Therefore, in the FREEDM project, a user defined ECN protocol is developed. The protocol is implemented in a simulated OPNET router module, and the communications performance with and without the improvement is compared to justify the function. The paper introduces the concept in the communications implementation in the FREEDM project as well as the origin for ECN (Explicit Congestion Notification). An algorithm to adjust the terminal data rate based on the ECN notification mechanism is provided, and its simulation is implemented.