A Time-Sharing Scheme to Alleviate Interference in Collocated Radio Equipments

The need to locate several radio transmitters and receivers in close proximity due to space limitations and yet be able to operate them simultaneously introduces severe interference. The purpose of this paper is to discuss the feasibility of using a time-sharing approach to alleviate or eliminate some of these problems. The central idea to be investigated is the concept of a switching arrangement such that individual equipments "take turns" in performing their designated function. That is, at any instant of time, only one equipment (transmitter or receiver) in the complex is communicating. The switching must be done at a rate such that no loss of information occurs. This switching rate is specified by the sampling theorem, where the rate is a function of the highest frequency component in the message. Attention is focused on the method of switching or sampling, with particular emphasis on the shape of the sampling signal. The trade-offs in terms of spectrum width, signal level, and numbers of equipments to be handled are examined for several sampling pulse shapes.