Abstract: Orthogonal transmit diversity is implemented by employing a data splitter (803) to subdivide channel information (801) into at least a first portion of bits (802) and a second portion of bits (804). Each portion is spread with its own Walsh code for eventual transmission to a mobile station via a predetermined carrier frequency. When the number of bits in the first and second portion (802, 804) are small, separate Walsh codes are used to maintain orthogonality. When the number of bits in the first and second portion (802, 804) are relatively large, a time-division multiplex transmission is used to maintain orthogonality. A controller (809) controls the subdivision of the channel information and also an interleaver (308) to further enhance the effects of the diversity transmission. Control information related to the subdivision is transmitted to the mobile station so the channel information can be accurately reconstructed prior to decoding.

Abstract: Different orthogonal codes (W.sub.x, W.sub.y) are used to spread common pilot channels (Pilot.sub.A) intended for transmission to a particular mobile station (106) within a coverage area (sector A) to implement forward link transmit diversity. The use of different orthogonal codes (W.sub.x, W.sub.y) for each pilot channel (Pilot.sub.A) allows the mobile station (106) to discern which pilot channel spread with a different orthogonal code includes corresponding traffic channel (TCH) information. This allows forward link transmit diversity to be enable/disabled based on conditions associated with the environment, the communications channel, etc. without a complete loss of information as seen by the mobile station (106).

Abstract: Different orthogonal codes (W.sub.x, W.sub.y) are used to spread common pilot channels (Pilot.sub.A) intended for transmission to a particular mobile station (106) within a coverage area (sector A) to implement forward link transmit diversity. By implementing separate, different orthogonal codes (W.sub.x, W.sub.y) for each pilot channel (Pilot.sub.A), the pilot signals transmitted via antennas (218, 222) to a common coverage area (sector A) are orthogonal to one another and thus do not degrade system performance. Additionally, the use of different orthogonal codes (W.sub.x, W.sub.y) for each pilot channel (Pilot.sub.A) allows the mobile station (106) to discern which pilot channel spread with a different orthogonal code includes corresponding traffic channel (TCH) information. This allows forward link transmit diversity to be enable/disabled based on conditions associated with the environment, the communications channel, etc. without a complete loss of information as seen by the mobile station (106).

Abstract: Correction of a round-trip delay within a communication system (100) takes place by receiving an uplink communication signal (119) over uplink communication signal paths (130-132) and determining what ray was utilized by a remote unit (113) in time aligning the uplink communication signal (119). In particular, a base station (101) analyzes the uplink communication signal (119) and predicts the ray that the remote unit (113) utilized for time alignment. Once the base station (101) has determined the ray that the remote unit (113) utilized in time alignment, the base station (101) corrects any calculation of round-trip delay accordingly.

Abstract: A method for determining a subscriber unit location in a communication system is provided. The method includes the steps of receiving a signal from the subscriber unit at a first base station, determining a first receive time of the signal based on a sequence of spreading symbols at the first base station, determining a first angle of arrival of the signal at the first base station, and determining the location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station. The signal is formed via modulation by the sequence of spreading symbols.

Abstract: After setting a base station to a transmit power level (12) which provides a signal at a subscriber unit having a target quality level, a fading characteristic of a communication channel between the subscriber unit and a base site is measured (13). The fading characteristic is then compared with a threshold value (14). The measuring (13) and comparing (14) are repeated until the fading characteristic crosses a threshold (15). Once the fading characteristic crosses the threshold for a receive Eb/No level that is representative of a e.g. static fading condition, the base transmit power that is transmitted to the subscriber is increased by a predetermined amount in anticipation of the need for an increased Eb/No for the case of a faded signal (61). The determination of the fading characteristic and threshold comparison may be performed at either the subscriber unit or the base station.

Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.

Abstract: A portable communication device (10) is controlled by voice recognition circuitry (20) remote from the portable communication device. The portable communication device includes apparatus for producing and transmitting a parametric representation of voice commands. The remote circuitry (which could possibly be a base station, a mobile repeater, or simply a dedicated box, separate from the portable) produces control signals, responsive to the parametric representation of voice commands, for controlling the portable communication device.

Abstract: A communication unit (10) transmits a first signal (12) that has a plurality of holes (44) therein during the occurrence of which another communication unit may interrupt. A repeater (14) receives the first signal and transmits a second signal (16) comprising the information in the first signal, and a plurality of digital coded squelch words synchronized with the holes to indicate the location of at least one of the holes in the first signal (i.e., the time at which at least one of the holes will occur). In one embodiment, each hole occurs after each pair of coded squelch words, and accordingly the pairs of coded squelch words are marked to indicate the times of occurrence of holes in the first signal.

Abstract: A linear amplifier comprising a feedback loop is stabilized by determining phase error between an error signal and a feedback signal and shifting the phase of a forward signal accordingly.

Abstract: A method for interrupting a radio transmission in a quasi-duplex radio-frequency communication system. The method of the present invention includes the step of transmitting a signal (22), with periodically-occuring holes (24) therein, by a first communicatioin unit (10) to at least a second communication unit (12). The transmitted signal (12) includes an audio information portion (16) and information packets (23). Each information packet (23) specifies the time of occurence of the next hole (24). The second communication unit (12) initiates an interruption of the transmission made by the first communication unit (10) by transmitting an interrupt request signal (31) to the first communication unit (10) at a time specified by an information packet (23) received by the second communication unit (12). When the first communication unit (10) receives the interrupt request signal (31), it processes the interrupt request signal (23) to determine whether it complies with predetermined criteria.

Abstract: A vehicle mounted mobile transceiver having a first and second frequency (11) communicates via a secondary mobile unit (51) with a short range portable unit (10). The portable unit (10) can be either a cordless microphone or a transceiver having a third and fourth frequency. The portable unit (10) allows a remotely positioned operator to transmit messages to a base station (13). To ensure security and reliable operation, the portable and vehicle mounted units use range burst signals and missed message signals to monitor receipt of data signals at the portable unit. The portable and secondary mobile unit communicate with one another via a first pair of frequencies and the vehicle mounted mobile transceiver and the base station communicate with one another via a second pair of different frequencies.

Abstract: A priority channel scan for use in radios capable for receiving at least two channels, wherein one of the channels is a priority communications channel. The radio periodically interrupts communications on the non-priority channel for very brief moments to allow monitoring of the priority channel for the presence of digital code word segments. These digital code word segments are stored until the complete code word can be reconstructed and compared against stored code words. When a match occurs, the radio switches to the priority channel to allow reception of a priority message occurring thereon.

Abstract: A vehicle mounted mobile transceiver (11) communicates via a secondary mobile unit (51) with a short range portable unit (10). The portable unit (10) can be either a cordless microphone or a transceiver. The portable unit (10) allows a remotely positioned operator to transmit messages to a base station (13). To ensure security and reliable operation, the portable and vehicle mounted units use digitized codes for ID and instruction purposes. These codes are newly generated from time to time by the vehicle mounted unit and are imparted to the portable unit via a battery charging interface. An improved remote squelch detect is also provided. The improved remote squelch detect substitutes the normal input to the vehicle primary mounted mobile transceiver (11) squelch gate for an audio signal.

Abstract: A simulcast transmission system is provided where a reference signal transmitted from a central station is utilized to phase-lock transmitters located at remote stations. The remote stations include a receiver for receiving the transmitted reference signal and a signal conditioner for conditioning the received reference signal for application to the transmitters. The transmitters include a phase-locked loop which may be followed by a multiplier for providing transmitter signals of predetermined frequencies. All the transmitters at the remote stations are phase locked to the reference signal transmitted from the central station. In the event that the reference signal transmitted by the central station is interrupted, the signal conditioner of the remote stations will operate in an open-loop fashion to provide the conditioned reference signal during the interruption.