Per-carrier Channel Isolation Measurement of a Broadband Wireless Communication System

A method for rapid determination of the intrinsic performance of the radio-frequency portion of a broadband communication system in terms of the per-carrier channel isolation characteristics is presented. It is applicable to a variety of systems employing multiple carriers for channelization or for providing multiple access, and is not dependent on a given type of baseband modulation. By observing the system forward transfer characteristics over the frequency allocated for a carrier as the drive conditions in the neighboring carriers are varied, the level of immunity of the carrier of concern to the interference resulting from system nonlinearity can be directly assessed. Advantages of this method include self-contained measurements on the RF section, standard measurement equipment, and applicability in both laboratory and field measurements. It is also applicable to characterize channels supported by sub-carriers in a system employing multilevel modulation schemes. Results of measurements performed on a local multipoint distribution system (LMDS) are presented.