First, a transmitter is randomly selected among all the transmitters. For this transmitter, a receiver is then randomly selected among all the receivers it has packets to send to. The third and the rest of the transmitter-receiver pairs are selected among the remaining stations in a similar manner. The nodes execute the algorithm identically by using a common random number generator seed. Thus, every transmitter arrives at the same decision.
Random selection allows fairness.
In the next slot, the packets are transmitted on the data channels according to the reservations made in the current slot using the control channel. To broadcast its control information, each transmitter needs to transmit N bits, where N is the number of nodes in the network. Thus, a total of bits need to be transmitted on the signaling channel per slot. One way to reduce the number of control bits exchanged in a slot, is to let fewer nodes exchange information bits among each other. This can be accomplished by breaking the set of nodes into G groups of size k each.