Abstract:
A method and apparatus reduces power consumption in a portable communication device (104) by predicting a user's location, movement and actions. The portable communication device (104) is powered by a battery (120) and includes a battery control (122) for decoupling portions of the communication device (104) from the battery. Historical records of control channel and call activity are maintained in memory (117) at the communication device (104). This data is used to predict calls. This permits the communication device (104) to conserve power in the battery (120) when no call activity is likely. The stored data is also used to predict what control channels should be scanned to search for a nearby base station (102). This permits the communication device (104) to scan a reduced number of control channels and reduces the time duration necessary for powering up the receiver (108) of the communication device (104).
Abstract:
A method and apparatus for mitigating error in a received communications signal includes an error mitigator (35) of a communication unit (12) which receives and performs mitigation based on an error indication. In a first embodiment the error indication is a phase or non-used data symbol indicating error in ADPCM data, and mitigation includes changing certain nibble values to different predetermined values. In a second embodiment the error indication may include other parameters, e.g., a CRC frame error indicator, and an error estimator (34) determines a level of corruption in the ADPCM data. The error mitigator (35) applies a predetermined set of replacement values based on the indicated level of corruption and the mitigated data is subsequently decoded in an ADPCM decoder (26).
Abstract:
A correlation circuit (200) for detecting a correct phase for data bits in a received data stream includes a clock generator (204) configured to generate a plurality of clock signals, each clock signal having a predetermined unique clock phase. A plurality of data correlators (210, 212, 214, 216, 218, 220) generate respective pass indications when respective unique clock phases are adequate for accurate detection of the data bits in the data stream. In response to the pass indications, a control circuit (206) provides a clock signal for clocking the data. The control circuit (206) includes a delay block (278) and decision logic (270) for selectively delaying one clock phase of the generated plurality of clock phases. The control circuit may provide one of the generated clock phases or a delayed clock phase for clocking the received data.
Abstract:
A nested digital phase lock loop (DPLL) circuit (400) provides center bit sampling for incoming recovered data (406). Included in the nested DPLL circuit (400) are a narrow bandwidth DPLL (402) and a wide bandwidth DPLL (404) which generate first (410) and second (428) recovered clock signals respectively. Initially the first recovered clock signal (410) is used to clock in the recovered data (406) until the narrowband DPLL (402) is stabilized. Once the narrowband DPLL (402) is stabilized, the second recovered clock signal (428) generated from the wideband DPLL (404) is switched in by a multiplexer (424). If for any reason the center bit sampled data becomes corrupted, a RESET occurs in the wideband loop (404) to zero out the phase shift of the second recovered clock signal (428) to match that of the narrow loop. Thus, when a RESET occurs, the wideband loop is tracking at exactly the same clock rate as the narrowband loop.
Abstract:
A base site (200) capable of being remotely calibrated includes a receiver (206) and transmitter (210). The base site (200) further includes a controller (208) for controlling the base site and for measuring a transmission parameter related to the received transmission message from handset (120). Once an update message is received from handset (120) controller (208) updates the operating parameter of the base site (200).
Abstract:
A method for seamless transfer of a communication link from a first radio telephone base station to a second radio telephone base station comprises the following steps performed at the first base station: (100) receiving a communication link request from a calling portable radio unit; (102) synchronizing with the calling portable radio unit; (104) determining whether the calling radio has handoff authorization; (108) connecting received data to a second base to allow for synchronization to the calling radio; (112) measuring a first RSSI level at the first base station for the calling radio; (114) determining whether the first RSSI level for the calling radio is below a first handoff threshold; (116) determining a second RSSI level for the calling radio, as measured at the second base station, is above a second handoff threshold, if the first RSSI level for the calling portable radio unit is below the first handoff threshold, (118) determining whether the second RSSI level for the calling portable radio unit is above a second handoff threshold, and (120) alerting the second base station to pick up the communication link. The method further comprises the following step performed at a second base station: (122) commencing to transmit in the frame immediately following the last transmit frame of the first base.
Abstract:
A transceiver (100) is provided for transmitting during the transmission bursts (12) of a frame and receiving during the receiving time-slot windows (14). The transceiver (100) includes a receiver (320) for receiving a repeating radio frequency data (16) signal at any time within the receiving time-slot window (14) and for demodulating the repeating radio frequency data signal down to a baseband data signal. A data detector and clock recovery device (330) recovers the valid data (CHMP) from the baseband data signal. For controlling the receiver (320) and data detector and clock recovery device (330), a control circuit (400) modifies the receiving time-slot windows (14) to only receive and detect when valid data is expected (52).
Abstract:
A radio communication device, having a receive mode and a transmit mode, includes a receiver portion, a transmitter portion, and multiple oscillators for providing reference waveforms for the radio communication device. During the receive mode, the receiver portion receives signals having a selected frequency, converts received signals to at least a first intermediate frequency (IF), and a transmitter oscillator produces a first waveform having a frequency equal to a multiple of the first intermediate frequency during the receive mode. During the transmit mode, the transmitter portion requires a reference waveform having an offset frequency equivalent to the first IF frequency to produce a radio frequency signal. Thus, the radio communication device also comprises a divider coupled to the transmitter oscillator for dividing the frequency of the first waveform to the required offset frequency in the transmit mode.
Abstract:
A base station allocates radio channels to radio telephone handsets in a second generation cordless telephone (CT2) communication systems by scanning each channel in a first band, and scanning each channel in a second band to measure an RSS level for each channel scanned. The base station scans the second band at a rate that is substantially faster than the rate at which it scans the first band. If a link request is received on a first channel within the first band, from a calling radio telephone, the base station determines whether the first channel has an RSS level above a predetermined threshold. If the RSS level of the first channel is above the threshold, and the calling radio telephone handset is capable of operating on the second band, the base station re-assigns a second channel, that is within the second band, to the calling radio telephone handset.
Abstract:
A system and method provide an enhanced listening experience for a user of a radio receiver or other device that receives broadcast or streamed content having a plurality of program channels. The method and system buffer designated channels at the receiver and, when switching among channels, play back the buffered designated channels during reception from a selected point therein depending on the channel or other criteria. When switching to a different channel during reception, a user is able to hear content in a buffered program channel with music from the start of a song, for example, whereas content in a channel with news, talk radio, or live sports is played back from live reception, even though the content segments are transmitted at different start times relative to their selected times for playback following a channel change. User controls allow navigation among buffered designated channels during reception.