A system for determining the location of a device in a wireless communication network includes at least one antenna for transmitting signals in a wireless communication network. A monitoring unit, located proximate to the at least one antenna, is operable for receiving, as a first input, signals transmitted by the antenna and signals from a device in the network and for receiving, as a second input, signals to be transmitted by the antenna. The monitoring unit includes at least one cancellation stage for modifying the second input and combining the modified second input with the first input to reduce the effect of the transmitted antenna signals on the monitoring unit first input.