BACKGROUND

Wireless communications are vital to everyday civilian and military life. Voice and data transmitted over any distance must be received with little to no error. In order to attain the range of communications necessary, communications systems are designed to utilize high power transmitters and sensitive receivers along with other RF processing techniques.

In many situations several radio transmitter/receiver combinations must be co-located to service the communications needs. An instance of this is found at installations such as at a military command post or vehicular installation which must oversee the actions of hundreds or even thousands of troops. These troops are generally widely dispersed and organized to communicate on different channels at the same time, requiring the commander to operate with several radios simultaneously. This presents a serious challenge to radio design engineers since in this configuration it can never be fully determined how many transmitters will be required to be active at the same time because any number of receivers must be tuned to distant stations. Cosite interference is the term used to describe the situation where a high power transmitter is active and interfering with a co-located receiver.

There are several methods used to mitigate cosite interference in communication systems design. One easy method is simple transmitter/receiver separation. This, however, is of limited use to the command post or vehicle that must be organized in a small area. Other methods include filtering, active cancellation and digital signal processing techniques or combinations...