consider a broadcast channel with n nodes and a transmission rate of r bps. suppose the broadcast channel uses polling (with an additional polling node) for multiple access. suppose the amount of time from when a node completes transmission until the subsequent node is permitted to transmit (that is, the polling delay) is dpoll. suppose that within a polling round, a given node is allowed to transmit at most q bits. further suppose node 1, initially with no bits to send, receives q bits to send. what is the maximum time from when node 1 receives the bits until it can begin to send them?