Abstract: A code division multiple access (CDMA) communication system in which cellular techniques are utilized in a wireless Private Branch Exchange (PBX) environment. A microcellular arrangement is defined in which a base station communicates user information signals using CDMA communication signals with subscriber terminals. A distributed antenna system is utilized in the system to provide multipath signals which facilitate signal diversity for enhanced system performance.

Abstract: A power control system for a cellular mobile telephone system in which system users communicate information signals between one another via at least one cell site using code division multiple access spread spectrum communication signals. The power control system controls transmission signal power for each cellular mobile telephone in the cellular mobile telephone system wherein each cellular mobile telephone has an antenna, transmitter and receiver and each cell-site also has an antenna, transmitter and receiver. Cell-site transmitted signal power is measured as received at the mobile unit. Transmitter power is adjusted at the mobile unit in an opposite manner with respect to increases and decreases in received signal power. A power control feedback scheme may also be utilized. At the cell-site communicating with the mobile unit, the mobile unit transmitted power is measured as received at the cell-site.

Abstract: A power control system for a cellular mobile telephone system in which system users communicate information signals between one another via at least one cell site using code division multiple access spread spectrum communication signals. The power control system controls transmission signal power for each cellular mobile telephone in the cellular mobile telephone system wherein each cellular mobile telephone has an antenna, transmitter and receiver and each cell-site also has an antenna, transmitter and receiver. Cell-site transmitted signal power is measured as received at the mobile unit. Transmitter power is adjusted at the mobile unit in an opposite manner with respect to increases and decreases in received signal power. A power control feedback scheme may also be utilized. At the cell-site communicating with the mobile unit, the mobile unit transmitted power is measured as received at the cell-site.

Abstract: A maximal length linear sequence pseudorandom noise (PN) sequence generator for generating an augmented length PN sequence of length 2.sup.N. The PN generator includes circuitry for generating a PN sequence of length 2.sup.N -1 chips. A sequence augmenting circuit is included which inserts at least one additional chip in the PN sequence at a predetermined position within the PN sequence so as to provide an output of an augmented PN sequence of length 2.sup.N chips. The generator may also include sequence shifting circuitry which is responsive to a mask input for providing a predetermined shift in the output augmented PN sequence without incurring a transition period where the shifted output is invalid.

Abstract: A system and method for determining the position of an airborne object, using a fixed station and a pair of earth orbit satellites whose positions are known. Separate periodic signals are transmitted from the fixed station via the first and second satellites to the object whose position is to be determined. The phase offset in periodic characteristics of the periodic signals as received from the first and second satellites is measured at the object. The phase offset corresponds to a realtive time difference in propagation of the signals traveling two different paths to the object. The object transmits via the first satellite a return signal indicative of the measured relative time difference. This return signal is activated some time in the future according to the object local time, which is slaved to receipt of the periodic signal sent through the first satellite. This future time is the start of the particular time period as decided by the fixed station's schedule.

Abstract: A spread spectrum receiver subsystem for utilization in a CDMA cellular telephone having a searcher receiver for scanning the time domain so as to use the PN processing gain and time discrimination properties of spread spectrum coding to determine the location in the time domain and the received signal strength of multiple receptions of a pilot signal traveling upon one or more physical propagation paths to reception. The searcher receiver provides a control signal indicative of the received pilot signals of greatest strength and corresponding time relationship. A data receiver receives spread spectrum communication signals accompanying each received pilot signal and is responsive to the searcher control signal for acquiring and demodulating a spread spectrum communication signal, concomitant with the pilot signal of greatest signal strength, and thus providing a corresponding information bearing encoded output signal.

Abstract: A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols.

Abstract: In a cellular telephone system a system for directing communications between a mobile user and cell-sites as a mobile user changes cell-site service areas. The mobile user includes an apparatus for, while in communication with another system user via one cell-site, determining a transition of the mobile user from the cell-site service area to the service area of another cell-site. The system includes circuitry responsive to the indication for coupling communications between the mobile user and the other system user via the new cell-site while the mobile user also remains in communication with the system user via the first cell-site. The system further includes apparatus responsive to the coupling of the communications between the mobile user and the other system user via the new cell-site for terminating the communications between the mobile user and another system user via cell-site with communications continuing between the mobile user and the system user via the new cell-site.

Abstract: A power control system for a cellular mobile telephone system in which system users communicate information signals between one another via at least one cell site using code division multiple access spread spectrum communication signals. The power control system controls transmission signal power for each cellular mobile telephone in the cellular mobile telephone system wherein each cellular mobile telephone has an antenna, transmitter and receiver and each cell-site also has an antenna, transmitter and receiver. Cell-site transmitted signal power is measured as received at the mobile unit. Transmitter power is adjusted at the mobile unit in an opposite manner with respect to increases and decreases in received signal power. A power control feedback scheme may also be utilized. At the cell-site communicating with the mobile unit, the mobile unit transmitted power is measured as received at the cell-site.

Abstract: A method and system for determining the position of an object using a fixed station and a plurality of earth orbit satellites whose positions are known. Separate periodic signals are transmitted from the fixed station via first and second satellites to the object whose postion is to be determined. The phase offset in periodic characteristics of the periodic signals as received from the first and second satellites is measured at the object. The phase offset corresponds to a relative time difference in propagation of the signals traveling two different paths to the object. The object transmits via the first satellite a return signal indicative of the measured relative time difference. This return signal is activated some time in the future according to the object local time, which is slaved to receipt of the periodic signal sent through the first satellite. This future time is the start of the particular time period as decided by the fixed station's schedule.

Abstract: A message communication system employing one or more centralized communication stations transferring messages through Earth orbit repeater satellites to or from mobile terminals with at least one central communication station having a first transceiver for transmitting a first communication signal to one or more mobile terminals and at least one mobile terminal having a second transceiver for receiving the first communication signal and demodulating it, and for transmitting at a predetermined duty cycle of the second transceiver, a second communication signal to at least one of the central communication stations. The preferred duty cycle over which the second communication signal is transmitted is about fifty percent of the second transceiver duty cycle. The communication system uses Time Division Multiplexed (TDM) communication signals using a number of channels as designated address channels with the remainder being used for data transfer.

Abstract: A message communication system employing one or more centralized communication stations transmitting messages through Earth orbit relay satellites to mobile receivers utilizing Time Division Multiplexed (TDM) communication signals having signal time frames divided into a series of transmission channels. A predetermined number of the channels are designated as address channels with the remainder being used for data transfer. Information transmitted on the address channels is used by receivers to determine both the presence of a message and its corresponding data transmission channel. Each system receiver scans, and tracks only the communication signal address channels until a message addressed to that receiver is detected, at which time the selected receiver changes channels to the designated data channel for reception of the message.

Abstract: A multiple access, spread spectrum communication system and method for providing high capacity communications to, from, or between a plurality of system users, using code-division-spread-spectrum communication signals. The communication system uses means for providing marginal isolation between user communication signals. The marginal isolation is provided by generating simultaneous multiple steerable beams; using an omni-directional antenna with polarization enhancement; using power control devices to adjust the output power for user generated communication signals either in response to their input activity level, or in accordance with a minimum allowable power for maintaining a communication link. The communication system can also employ a means for transmitting a predetermined pilot chip sequence contiguous with the code-division-spread-spectrum communication signals.

Abstract: A system in a subscriber television network for enabling descrambling of a received scrambled signal on a prepaid basis and/or an impulse-purchase basis. A received mask signal uniquely related to the scrambled signal is compared with a received authorization signal indicating whether the subscriber is authorized to receive the scrambled signal on a prepaid basis and a prepaid signal for enabling descrambling is provided when the compared signals match. A not-prepaid signal is provided when they do not match. A received cost signal indicating the charge for descrambling the scrambled signal and a received credit signal indicating the subscriber's endlessly accumulated credit are processed with reference to a stored record of the subscriber's prior accumulated charges to determine whether the subscriber has sufficient available credit to pay for descrambling of the scrambled signal.

Abstract: A system in a subscriber television network for enabling descrambling of a received scrambled signal on a prepaid basis and/or an impulse-purchase basis. A received mask signal uniquely related to the scrambled signal is compared with a received authorization signal indicating whether the subscriber is authorized to receive the scrambled signal on a prepaid basis and a prepaid signal for enabling descrambling is provided when the compared signals match. A not-prepaid signal is provided when they do not match. A received cost signal indicating the charge for descrambling the scrambled signal and a received credit signal indicating only the subscriber's accumulated credit are processed with reference to a stored record of the subscriber's prior accumulated charges to determine whether the subscriber has sufficient available credit to pay for descrambling of the scrambled signal.

Abstract: A system and method for scrambling and selectively descrambling television signals that are transmitted to subscribers' descramblers in a subscription television system. A working key signal is generated by processing an "initialization vector" signal in accordance with the DES algorithm upon the algorithm being keyed by either a common category key signal or some other key signal. A unique encryption keystream is generated by processing the initialization vector signal in accordance with the DES algorithm upon the algorithm being keyed by the working key signal. A television signal is scrambled in accordance with the unique encryption keystream to provide a scrambled television signal.

Abstract: A self-shifting last-in-first-out stack for a data processing system, including a plurality of parallel linear arrays of data storage cells interconnected for enabling stored data to be shifted to or from an adjacent cell within the same array. The parallel (n)th cells from the top of the stack in the respective arrays define the (n)th word level in the stack.