Abstract: Base transmitters (116) of a wireless messaging system are pre-programmed (802) with location identifiers (216) for identifying the positions at which the base transmitters are located. In response to an inbound message from a portable subscriber unit (122), a fixed portion (102) of the wireless messaging system makes an estimate (808) of a location at which the portable subscriber unit is positioned. A controller (112) sends (812) an outbound message (614) and the estimate to the base transmitters, and the base transmitters calculate (812) distances between themselves and the portable subscriber unit, based upon the location identifiers and the estimate. In addition, the base transmitters independently make a decision (818) whether to transmit the outbound message, based upon a comparison of a predetermined rule with the distance of the base transmitter from the portable subscriber unit.

Abstract: A variable-class linear amplifier (600, 800, 900) applies a supply type of envelope modulation to an RF power amplifier operating in or near compression at highest envelope amplitudes, and transitions gradually to an envelope tracking type of operation at intermediate envelope amplitudes. The amplifier further transitions gradually to a linear class of operation with a constant supply voltage (508) at lowest envelope amplitudes.

Abstract: 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.

Abstract: A method of providing compensation for distortion imparted to an input signal, principally by an amplifier (18), compares a delayed version of the input signal (34) to the amplifier's output signal. The result of the comparison is an error signal that is fed back to minimize distortion. This feedback technique is applied to a transmitter (10) in combination with predistortion that is selected to compensate for at least some of the distortion provided by the transmitter's output amplifier (18). The remainder of the compensation is provided by the error signal which can be generated by a relatively low gain analog feedback loop.