This paper describes the design and performance of a spread-spectrum medium frequency (MF) radio network. The network utilizes a simulcast time slotted transmission scheme in which radios that receive a data message in one time slot repeat the message in the next slot. Spread-spectrum radio designs that operate efficiently with simulcast under a variety of channel conditions are investigated. The performance of the radio network is characterized in terms of radio connectivity and message reaction time.

A deterministic coding scheme for reliable transmission over the Gaussian broadcast channel with two receivers is considered. The coding scheme is based upon Slepian's permutation mudulation codes. It is shown that it is relatively easy for both receivers to accomplish maximum likelihood detection even though one receiver must instrument a composite hypothesis test. Bounds on the performance of various codes are given. The parameters of the codes are chosen in order to achieve the best performance. The performance of these best codes are compared with results predicted by random coding and with time sharing of ordinary permutation codes.