Abstract: To reduce the power consumption of a remote unit in a dispatch system the remote unit enters a dormant state. A base station transmits a forward link broadcast signal and monitors a common access channel. A first remote unit continually receives and decodes the forward link broadcast signal and determines whether said forward link broadcast signal comprises active signals. If the remote unit determines that the forward link broadcast signal comprises no active signals for some a duration T.sub.1, the first remote unit enters a dormant mode. In the dormant mode the remote unit sporadically receives and decodes said forward link broadcast signal. If this remote unit or any other remote unit on the same net presses a push to talk button, it transmits a message on the common access channel. In response, every remote unit on the net which is in a dormant state exits the dormant state and continually monitors the forward link broadcast signal.

Abstract: A method and apparatus providing centralized power control in a multiple base station communication configuration. Each base station in a system operates to control both over the forward link power it transmits and the reverse link power from the remote units. A radio link manger provides a common threshold for determining the proper power level of the reverse link signal at each base station. The radio link manager also provides a ratio of the forward link signal strength to a pilot signal strength to control forward link power control. The radio link manager provides the threshold and the ratio uniformly to all base stations thus providing a uniform operating point for all base stations in a system and thus increasing capacity. The same centralized power control is easily expanded to provide a mechanism for intersystem soft handoff.

Abstract: A keypad is operated by the user to generate keypad data indicative of a destination telephone number. A storage area stores data related to the calling plan and containing data indicative of call restrictions that may apply to the destination telephone number. A call restriction storage area is used to store user-selectable call restriction data. A processor accepts and uses keypad data to access the data storage area. The processor compares data indicative of call restrictions that may apply to the destination telephone number with the user-selectable call restriction data to determine if any user-selectable call restrictions apply to the destination telephone number. The processor sets an enable signal to an enabled state if no call restrictions apply to the destination telephone number and sets the enable signal to a disabled state if call restrictions do apply to the destination telephone number.

Abstract: A multi-stage low power, high dynamic range variable gain amplifier comprises an input stage cascaded with one or more current amplifier stages, whereby the gain of each stage may be independently controlled. The input stage may be comprised of a variable transconductance amplifier using variable emitter degeneration. The current amplifier may be comprised of a differential Darlington amplifier coupled to a differential cascode amplifier. The transconductance amplifier converts an input voltage signal to a current signal. The variable gain amplifier is designed for efficient low power operation.

Abstract: A system and method for assigning hauling vehicles to freight loads within a freight transportation system is disclosed herein. The system includes a satellite navigation subsystem for providing vehicle and load position data useable to determine the locations of each hauling vehicle and freight load. The position data may also be utilized to determine a set of deadhead distances required to be traversed by ones of the hauling vehicles unencumbered with freight loads while en route to load pick-up locations. Each unencumbered tractor vehicle is then efficiently matched with an available freight load in accordance with the compiled sets of deadhead distances and a set of potential pick-up times. Objectives such as punctual load pick-up and delivery, full utilization of available tractor vehicles, and maintaining scheduled driver home-base times of arrival may be achieved through "relay" operations.

Abstract: A conference calling system for a wireless communications channel. The system is adapted for use with a channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively. The system includes a circuit for receiving an encoded signal from at least one of the transmitters. A second circuit determines which of the participants is speaking from the received encoded signal. A third circuit is provided for re-transmitting an encoded signal received from the speaking participant to the other participants. In the illustrative implementation, the encoded signals are variable rate speech vocoded signals in which speech is vocoded at full rate, silence is vocoded at 1/8th rate and the 1/2 and 1/4 rates are used as transitional rates. In the illustrative implementation, the speaker's signal is identified by examining the rate of the received vocoded signals.

Abstract: In a dispatch system, power of the forward link broadcast channel transmitted from a base station is controlled such that the power level is the minimum necessary and such that transmission of the forward link broadcast channel is terminated if no remote unit is located within the coverage area of the base station. In addition to transmitting a forward link broadcast signal, the base station monitors an access channel. A first remote unit in the base station coverage area receives and decodes the forward link broadcast signal. The first remote unit determines a signal quality of said forward link broadcast signal. If the signal quality is unacceptable, the remote unit transmits a power request access message. The base station responds to the request by increasing the transmission power of forward link broadcast channel. If no requests are received at the base station, the forward link broadcast channel is slowly decreased to a minimum.

Abstract: A circuit card assembly is provided for use in testing a system wherein the circuit card assembly employs a surface mount device such as a field programmable gate array. The circuit card assembly includes severable traces on a bottom surface of the assembly connecting pairs of near and far vias. The severable traces and the pairs of near and far vias allow the circuit card assembly to be selectively re-worked to accommodate changes to the design of the surface mount device. Hence, a new circuit card assembly need not be designed and fabricated each time the design or programming of the surface mount device is changed. The circuit card assembly includes a network of interconnection paths wherein each path to or from a pin terminal area of the circuit card assembly passes along at least one severable trace between at least one pair of near and far vias along the bottom surface of the assembly.

Abstract: A method and apparatus for operating a wireless telecommunication system utilizing code division multiple access (CDMA) over-the-air with a Global System for Mobile communications (GSM) A-interface based network is described. A CDMA radio frequency (RF) signal interface provides a bi-directional interface to a subscriber unit, and a Global System for Mobile (GSM) communications A-interface SS7 transport provides a bi-directional interface with GSM mobile services switching center (MSC). Additionally, a transparent message transport is provided over which signaling messages defined in the GSM A-interface protocol are exchanged between the GSM MSC and a subscriber unit. Other signaling message generating by the GSM MSC and subscriber unit are processed and various actions are taken in response, including the configuration and control of signal processing resources.

Abstract: First and second data sources transmit a data signal on a data connection and a transmit clock signal on a clock connection. The data signal is clocked into a FIFO resident in the network interface equipment in response to the transmit clock signal, and out of the FIFO to the network in response to a reference clock signal. The FIFO generates a signal indicating how full it is and a local clock generator which generates the transmit clock signal in response to this status indication signal. The first and second data sources hold the data signal and transmit clock signal high for longer than a single period of the reference clock signal when switching between them. The local clock generator alters an average rate of the transmit clock signal in response to the status indication signal from the FIFO in order to keep it half-full.

Abstract: In the present invention, the slave base station attains synchronization with the reference base station through messages transmitted from and received by a mobile station in the soft handoff region between the reference base station and the slave base station. First, the round trip delay between the mobile station and the reference base station is measured by the reference base station. Once the mobile station acquires the signal from the slave base station, it measures and reports the difference between the amount of time it takes a signal to travel from the reference base station to it and the amount of time it takes a signal to travel from the slave base station to it. The last measurement necessary is a measurement by the slave base station of the time difference between the time it received the reverse link signal from the mobile and station the time it transmitted a signal to the mobile station.

Abstract: An amplifier circuit for providing an amplified signal in response to an input signal. The amplifier circuit includes an input network for applying the input signal to a selected at least one of a plurality of amplifier stages. An output network is provided for coupling the amplified signal from the selected at least one amplifier stage. The appropriate amplifier stage is selected by a control circuit in response to a desired power value of the amplified signal. By selectively activating only the amplifier stage(s) that are necessary to provide the desired level of output power, increased DC efficiency can be accomplished in applications that require an amplifier which operates linearly over a wide dynamic range.

Abstract: A system and method for determining the transmission rate of a data signal at a receiver of a variable rate communications system. A vocoder at a transmitter encodes a frame of data into symbols according to one of a set of discrete data rates. When the data rate is lower than the maximum, each symbol is repeated a number of times as required to achieve a constant number of symbols in each frame. The data signal is transmitted at a power proportional to the data rate of the frame. A reference signal is also transmitted. The reference signal is transmitted at a constant power. Further, the data signal has the same carrier frequency as a reference signal so that they exhibit the same fading characteristics as they are transmitted through the channel. At a receiver, the power of the data signal and the power of reference signal are measured as received.

Abstract: A method for handoff of an analog connection within a cellular communication system which relies upon mobile station synchronization to a system time is disclosed herein. In order to reduce the acquisition time for a mobile station commencing operation in a digital mode, an estimate of master system time is transferred to the mobile station in analog mode before entering digital mode. The alignment operates within the protocols of existing analog systems, and hence requires only minimal changes in the mobile station. Time alignment may be initiated upon the base station sending to the mobile station a command to continually transmit a periodic signaling tone. The base station compares the phase of the signaling tone from the mobile station to a master system clock and determines an error signal. The base station notifies the mobile station to delay or advance in time the transmitted signaling tones based on the error signal.

Abstract: A method and apparatus for selecting a communication system in accordance with geographic region of the subscriber station. The subscriber station first attempts to determine its geographic region. It does so by attempting to acquire a system which covers the region. Once the subscriber station has determined its geographic region, the subscriber station then determines whether the acquired system is the most desirable system for use in the geographical region. If it is the most desirable system for use in the geographical region, the subscriber station registers with the acquired system. If it is not the most desirable system for use in the geographical region, the subscriber station attempts to acquire a more desirable system.

Abstract: The finite impulse response (FIR) filter is implemented as a table using read-only memory (ROM). The FIR filter table stores a pre-calculated output filter value for each permissible combination of input values to be filtered. Streams of input values are successively shifted into the table and corresponding output values are successively output. In an exemplary implementation, the FIR filter is employed within a digital cellular telephone for use in smoothing a digital signal to be transmitted. The size of the required FIR filter table is minimized by exploiting constraints imposed upon the signal to be filtered and by exploiting linearity and symmetry within the filter itself. More specifically, the telephone employs a data burst randomizer to provide a data signal composed of sequences of null or 0 values and sequences of antipodal values (+1's and -1's).

Abstract: An integrated search processor used in a modem for a spread spectrum communications system buffers receive samples and utilizes a time sliced transform processor operating on successive offsets from the buffer. The search processor autonomously steps through a search as configured by a microprocessor specified search parameter set, which can include the group of antennas to search over, the starting offset and width of the search window to search over, and the number of Walsh symbols to accumulate results at each offset. The search processor calculates the correlation energy at each offset, and presents a summary report of the best paths found in the search to use for demodulation element reassignment. The search is done in a linear fashion independent of the probability that a signal being searched for was transmitted at any given time.

Abstract: The present invention is a method and apparatus for integrating a personal communication system with a cable television plant. A set of radio antenna devices (RAD) are connected to the cable plant. The RADs provide frequency conversion and power control of signal received from the cable plant for wireless transmission to the remote units. The RADs also provide power control and frequency conversion of wireless signals received from the remote units for transmission by the RADs onto the cable plant. In addition to the functions of standard base stations and centralized controller, the CATV base station must also compensate for gain variations in the cable plant. The downstream power control is regulated by a RAD reference signal which can be hidden within the CDMA signal for maximum efficiency. The upstream power control is regulated by an upstream gain reference signal which is individually transmitted by each RAD on the upstream link.

Abstract: A plurality of methods for achieving the softer handoff process such that the performance of a system is improved. A first method is based on delaying the softer handoff process. A second method is based on reducing the power of transmissions from the sector having the weakest signal strength. A third method is based on eliminating transmissions from the sector having the weakest signal strength. In all three methods, reverse link demodulation in each sector may continue with or without the transmission of the forward link. In all three methods the operation could be based on the signal strength of the reverse link signal or the forward link. It is also possible to combine two or more of these methods to create a hybrid method.

Abstract: A novel and improved method and apparatus for providing an interface to a digital wireless telephone system compatible with standard analog wire line telephones, analog wire line fax machines, and computer modems is described. At the start of a telephone call, a data pump interprets the digits dialed, and if a first set of digits are received a control system configures the data pump for processing analog fax data. If a second set of digits are received, the control system configures the data pump for processing analog computer modem data. If a telephone number is received, the control system configures the interface system to pass additional data to a vocoder which encodes any digitized audio information received.