Abstract: A method and apparatus samples (902) a currently received symbol to form sampled values corresponding to sampling times, and evaluates (904) the currently received symbol to determine (906) its value. The method and apparatus recalls (908) a last previously received symbol and selects (916), from a plurality of thresholds (302), a threshold based upon the currently received symbol and the last previously received symbol. The threshold is known to be crossed consistently midway in time between the centers of two adjacent nominal symbols determined by the currently received symbol and the last previously received symbol. The sampled values are compared (920) to locate two adjacent samples, one having a first sampled value greater than the threshold and one having a second sampled value less than or equal to the threshold. A timing phase error is then computed (922, 924) from the first and second sampled values.

Abstract: A radio communication system (100) implements a frequency reuse plan by sending a message (308) simultaneously with other messages in a plurality of cell clusters (202-208) utilizing the frequency reuse plan, which provides a message carrier-to-interference ratio (C/I) sufficient for reception of the message when a receiver (104) is adjusted in accordance with a periodically transmitted pilot symbol (402-408). The C/I is smaller than preferred for reception of the pilot symbol. The pilot symbol is periodically transmitting simultaneously with other pilot symbols in a time diverse manner such that pilot symbol transmissions for adjacent ones of the plurality of cell clusters occur in non-overlapping time slots, thereby generating the larger C/I preferred for reception of the pilot symbol. The pilot symbol and the message are received by the receiver, and the receiver is adjusted in accordance with the pilot symbol to demodulate the message.

Abstract: A receiver (109) and a method therein arranged and constructed to receive a signal using a noncoherent matched filter structure including a frequency detector (205) arranged to process a first portion (602) of the signal to provide a frequency error; a timing detector (206), responsive to the frequency error, arranged to process a second portion (604) of the signal to provide a timing error; and a symbol detector (209), responsive to the frequency error and the timing error, arranged to process a symbol portion (606) of the signal to provide a detected symbol.

Abstract: A fixed system receiver (107) operates in a synchronization mode which is one of a synchronous mode and an asynchronous mode. A system controller (102) transmits a response command which includes a preamble indicator corresponding to the synchronization mode of the fixed system receiver (107). A selective call radio (106) receives and decodes the preamble indicator and generates a response message data unit (312). The synchronous header data packet (660) is preceded by a synchronizing packet (650) when the preamble indicator indicates the asynchronous mode and is not preceded by the synchronizing packet (650) when the preamble indicator indicates the synchronous mode. The selective call radio (106) transmits the response message data unit (312). The fixed system receiver (107) acquires symbol recovery timing and synchronizes to data packet boundaries of the response message data unit (312), using the synchronizing packet (650) when included.

Abstract: A method and apparatus minimize false detection of packet data in a receiver (202) due to noise in a communication system (100) utilizing time slots (420). Some time slots (420) contain a data packet (418), while others contain only noise. The data packet (418) includes a sync word (602) and an error-detecting code word (604, 606, 608). The receiver (202) is synchronized (1006, 1008) with a nominal predetermined timing of the time slots (420), and determines (1014) time windows (808) for receiving the data packets (418). During each of the time windows (808) data is received, demodulated, and stored (1016), and a predetermined portion of the data stored is searched (1018) to locate a point of maximum correlation between the data and a data template (902) matching the sync word (602).

Abstract: A method of synchronizing to a signal includes first performing a rough synchronization and then a fine synchronization to a sync word. The fine synchronization includes comparing a stored portion of the sync word to a received portion. By adjusting the timing and then performing additional correlations, the timing for the best correlation can be obtained. The bit clock is then adjusted so that subsequent data samples can be taken as close to bit center as possible.