Power line communication apparatus and method

To provide a communication device capable of transmitting and receiving data by the estimated and evaluated to high throughput channel characteristics with high accuracy. A divides the variation cycle L of the channel characteristics into a plurality of sections (n ​​period) is repeated to make a transmission path evaluation of only any one section of one beacon period per n segments, all n segments make the transmission path evaluation. Beacon period T is set according to (T = L × m / n). Incidentally, n is an integer of 2 or more, m is an integer greatest common divisor of the n or more and n is 1. .FIELD 2