LIMITING AN INTERVAL OF CARRIER CANCELLATION AND REDUCING ERRORS CAUSED BY INTERSYMBOL INTERFERENCE DURING A SIMULCAST TRANSMISSION

摘要

In a messaging system having a plurality of simulcasting base transmitters (104), a plurality of pseudorandom sequence generators (216) are provided (402) for the plurality of base transmitters. The plurality of pseudorandom sequence generators are arranged (403) to ensure that they generate a plurality of pseudorandom sequences having sub-sequences that are different from one another during concurrent transmissions by the plurality of base transmitters. A cancellation-affecting parameter of the plurality of base transmitters is adjusted (404, 406, 408) in accordance with the plurality of pseudorandom sequences during the simulcast transmission from the plurality of base transmitters to limit intervals of carrier cancellation. In addition, a controller (512) controls (1106) at least two transmitters (702) to transmit at least two simulcast signals (902, 904) during a time period. The at least two simulcast signals produce intersymbol interference at a receiver. At least one of the transmitters changes (1108) its output amplitude during a portion of the time period, thereby altering the intersymbol interference during the portion of the time period.