d as clashed, increase K by n1, where n is an integer, (b) if the previous slot was available for requests and a request was successfully received therein, decrease K by n2, K having a lower limit of 1 and n2 being an integer, (c) if the previous slot was available for requests and was observed as empty, decrease K by n3, K having a lower limit of 1 and n3 being an integer, (d) if the previous s