Abstract: A searcher receiver (114) includes a sample buffer (202) which stores signal samples loaded using a real time clock. A real time linear sequence generator (RT LSG) (206) stores an initial state and is clocked using the real time clock. The contents of the RT LSG are loaded into a non-real time linear sequence generator (NRT LSG) (208) when sample processing begins Samples are correlated using a non-real time clock to allow signal processing to be uncoupled from the chip rate. The analog front end (108) may be powered down or tuned to another frequency during non-real time processing.

Abstract: An apparatus (100) maintains a Pilot Set in a digital communication system that utilizes Code Division Multiple Access. The apparatus comprises a logic and control circuit (113) for providing instructions to a searcher receiver (109). The searcher receiver, in response to the instructions, sequentially scans active pilots, then candidate pilots, and then pre-candidate pilots. The scan of the pre-candidate pilots continues until all but a predetermined number of pre-candidate pilots have been promoted or demoted. Then the searcher receiver alternately scans the predetermined number of pre-candidate pilots and the neighbor pilots. The searcher receiver terminates alternate scans of the predetermined number of pre-candidate pilots and the neighbor pilots when a one of the neighbor pilots is promoted, and resumes the scan of the pre-candidate pilots.

Abstract: A searcher receiver (114) includes a sample buffer (202) which stores signal samples loaded using a real time clock. A real time linear sequence generator (RT LSG) (206) stores an initial state and is clocked using the real time clock. The contents of the RT LSG are loaded into a non-real time linear sequence generator (NRT LSG) (208) when sample processing begins. Samples are correlated using a non-real time clock to allow signal processing to be uncoupled from the chip rate. The analog front end (108) may be powered down or tuned to another frequency during non-real time processing.

Abstract: A radiotelephone (104) in a radiotelephone system (100) enters a low power sleep mode and times the duration of the sleep mode using a sleep clock generator (205) having a coarse resolution. The radiotelephone synchronizes timing of the radiotelephone to system timing using an oscillator (116) having a fine resolution. The radiotelephone then exits the low power sleep mode synchronized with system timing.

Abstract: A radiotelephone (121) employs a service detection circuit (125) comprising at least one chip-rate detector (109) that measures the energy of the autocorrelation of a received composite CDMA signal and employs a different time delay for each measurement of the energy. A threshold detection circuit (127) combines the measured energies and determines that service is available if the combined energies exceeds a threshold, and determines service is unavailable otherwise. The chip-rate detectors (109) can be coupled in parallel to provide simultaneous measurements of the energy of the autocorrelation of the received composite CDMA signal, or a single chip-rate detector (109) can serially measure the energy of the autocorrelation of the received composite CDMA signal.

Abstract: Prior to entry into a low-power sleep mode, a radiotelephone (104) in a radiotelephone system (100) calculates in advance the timing required to wake up selected portions of the radiotelephone and stores the calculated wakeup times in registers (216). Also prior to entry into sleep mode, local timing of the radiotelephone is synchronized to received PN roll boundaries from the radiotelephone system. In the sleep mode, the radiotelephone uses a sleep timer (210) to simulate system timing. When the sleep timer (210) matches the stored wakeup times, the radiotelephone re-activates the selected portions of the radiotelephone, such as an oscillator (116) and a radio frequency portion (109) of an analog front end (108), to exit the sleep mode and reacquire communication with the system. This also permits an early exit from sleep mode, for example to service an interrupt, while maintaining system timing.

Abstract: A wireless communication device 100 acquires a pilot channel before an assigned slot when the wireless communication device is operating in the slotted mode of a CDMA system. The wireless communication device comprises a searcher receiver 107 that determines the short-term average pilot strength of active and neighbor pilot channels. Finger receivers 107 determine the long-term average pilot strength of the active and neighbor pilot channels. A logic and control circuit 113 assigns the finger receivers to the pilot channels according to their short-term average pilot strength, determines if the long-term average pilot strength of a neighbor channel is greater than the active pilot channel's pilot strength, and determines to hand off to the neighbor pilot channel with the greater long-term average pilot strength. Moreover, an early detection correlation length can be dynamically adjusted according to the pilot strength of the active pilot channel to shorten the pilot acquisition process.