Abstract: A communication apparatus transmits data by adaptively selecting at least one of an error-correction coding rate and a modulation method so that the error rate of data transmission is within a target error rate at a destination. In the communication apparatus, a transmission-parameter generating unit selects at least one of an error-correction coding rate and a modulation method based on the number of hops, transmission channel characteristics, and the target error rate, thus generating at least one transmission parameter, and an error-correction coding unit and a modulating unit adaptively perform either or both error-correction coding and modulation according to the transmission parameter.

Abstract: A multicast connection control apparatus provided in a branching-and-consolidating node connecting a source terminal to a plurality of destination terminals for branching information over the forward connection or consolidating information over the backward connection in a multicast connection ATM network system includes a congested status management table for managing congested status in all RM cells and a controller. The controller transmits only an uncongested status RM cell transmitted thereto last over the backward connection when all the connections in a sequence are found to be in the uncongested state. The controller also transmits only a congested status RM cell over the backward connection when one of the connections is found to be in the congested state and cancels the subsequent transmission of the congested status RM cells in the same sequence over the backward connection.