Abstract: A wireless communication system (10) employing quadrature amplitude modulation techniques comprises a system controller (22), at least one radio frequency base transmitter (26), and at least one wireless communication device (35). The system controller (22) generates a downlink call (34) for transmission between the radio frequency base transmitter (26) and the wireless communication device (35). Multiplexing an I-channel bit stream (74) comprised of a first set of calls (70) interleaved together and a Q-channel bit stream (80) comprised of a second set of calls (76) interleaved together generates the downlink call (34). One wireless communication device demultiplexes the downlink call (34) and processes the I-channel bit stream (74). Another wireless communication device demultiplexes the downlink call (34) and processes the Q-channel bit stream (80).

Abstract: A method for setting up a link for a call in a narrowband cellular communication system (100) includes, in a selective call radio (106), determining a transmitter identity and a signal quality (310, 315) of a strongest monitoring channel of a set of N monitoring channels, each of which has propagation characteristics that closely represent propagation characteristics of one of N groups of channels, and transmitting a report (330) of the transmitter identity and a signal quality of the strongest monitoring channel; and includes, in a system controller, receiving the report (405), choosing an available outbound resource (425, 430) in a first group of the N groups of channels, wherein the first group includes the strongest monitoring channel, and establishing the call (555) using the chosen available outbound resource at a bit rate that is a highest bit rate that is compatible with the signal quality.

Abstract: A communication system (700) comprises a plurality of base sites (702-708) which include a first antenna (712) for transmitting a synchronous communication protocol such as a paging protocol and a second antenna (714) for transmitting a rotating phase signal. A communication device (250) takes the synchronous communication protocol and develops a reference signal (220) from the received protocol. The communication device (250) takes the reference signal (220) and the received rotating phase signal (214) and uses a phase detector (216) to produce a phase difference signal (232) which is substantially equal to the angle of the communication device (250) with respect to the particular base site (702-708) which transmitted the signals. In order to determine the location of the communication device at least two such phase difference signals (232), one phase difference signal from at least two different base sites is determined.

Abstract: A method and apparatus for time-scale modification of speech using a modified version of the Waveform Similarity based Overlap-Add technique (WSOLA) comprises the steps of storing a portion of an input speech signal in a memory, analyzing the portion of the input speech signal to determined at least one filtered pitch value, calculating an estimated pitch value (12) from the at least one filtered pitch value, determining a segment size (14) in response to the estimated pitch value (12), the segment size (14) having a value greater than the estimated pitch value (12), and time-scale compressing (18) the input speech signal in response to the segment size determined.

Abstract: A digital transmission system for a selective call message communication network such as a paging network utilizes a quadrature amplitude modulation (QAM) transmitter (40) and receiver (42). The QAM transmitter (40) receives as a modulating input thereto, a message data encoded signal with a pilot carrier in a notch of the power spectrum of the signal. In order to generate the signal, the system generates a Hilbert transform of a wave-form representing message data to be transmitted. The Hilbert transform and message data waveform are combined to provide a positive frequency component and a negative frequency component. These frequency components are shifted apart and combined to provide a notch in which a DC component can be added to form a pilot carrier. A receiver of the system removes the pilot carrier from a received signal and shifts the positive and negative frequency components together to recover the message data.

Abstract: A radio communication system (100) includes a system controller (102) for encoding data information to generate data messages which have periodic error protection at one or more burst error frequencies. The system controller (102) transmits one or more of the data messages to at least two transmitters (103) for simultaneous transmission of the one or more data messages. The first and second transmitters (103) have radio carrier frequencies which are offset by an offset frequency which is substantially equivalent to one of the one or more burst error frequencies. A selective call receiver (106) receives and decodes a radio signal including a data message having periodic burst errors at the offset frequency and wherein the data message includes encoding which provides substantial periodic burst error protection at the offset frequency.

Abstract: The present invention comprises a method for compressing a plurality of voice signals within a voice communication resource (see FIG. 6) having a given bandwidth within a voice communication system (100). The method comprises the steps of subchanneling the voice communication resource into a plurality of subchannels (441, 442, 443), placing a pair of the plurality of voice signals (401, 402) on a subchannel (441); modulating the pair of the plurality of voice signals (401, 402) about a pilot signal (581) within the subchannel (441) using single sideband modulation; and compressing the time of each of the voice signals (401, 402) within the plurality of subchannels (441, 442, 443), wherein these step provide a compressed voice signal.