This paper presents the performance evaluation and analysis at the physical layer of a peer-to-peer communication system based on IEEE 802.11g. This system is associated to a basic communications system, identifying source, channel and receiver. An Ad-hoc network is described, test scenarios and parameters are defined in order to evaluate the performance, finally we show the results of the different tests obtained from the system implementation in the 2.4 GHz ISM (Industrial, Scientific and Medical) band in real scenarios and its behavior against interference.