Abstract: An adaptive method controls the operation of multiple beam antenna systems used in communication satellite transponders. This method adaptively controls the coverage area assignments, frequency assignments, transmitted power level assignments, and component allocation assignments of these multiple beam antenna transponders in response to the existing and time varying demands for satellite resources. The method adaptively controls and manages the operation of the satellite transponders to optimize the overall capacity of the communication satellite.

Abstract: A space-based communication system (30), includes a transmission terminal having a transmission antenna (42) and a power amplifier (40) to power the transmission antenna, the power amplifier to generate a power output sufficient to generate an RF signal through the transmission antenna (42), a receive terminal including a receive antenna (45) to receive the RF signal from the transmission terminal and a low noise amplifier (43) to amplify the RF signal channeled through the receive antenna, and a thermoelectric cooler (62) for cooling the low noise amplifier (43) to a predetermined temperature for increasing the sensitivity of the low noise amplifier to minimize the power output generated by the power amplifier required to generate the RF signal thereby minimizing the overall power requirements of the spaced-based communication system (30).

Abstract: A non-contact IC card includes a CPU for processing data, a memory for storing a program for controlling the CPU, an antenna for transmitting data and receiving data manner, a plurality of receivers each having a different signal detection level for detecting a signal received by the antenna, a selector for selecting one of the plurality of receivers and connecting it to the CPU, and a transmitter for transmitting a signal from the CPU through the antenna.

Abstract: A method and system for increasing the signal margin of a radiocommunication link to provide a short message service which is reliable, even under non-ideal conditions. According to the method, an increase in transmission power is used in combination with bit repetition to increase signal margin without complications in the mobile unit design, significant delay, or co-channel interference. Where a more significant increase in signal margin is desired, when a longer message is required, or for voice messages, the message may be stored and the mobile unit alerted of the message.

Abstract: A receiver for a spectrum spread communication system capable of eliminating a deterioration in receive quality due to fading by multipass. A signal of which a spectrum is spread by a direct spread modulation system is transmitted from a transmit side unit. A receive side unit is provided with a plurality of receive antennas, through which receive signals are fed to receiver circuits, followed by conversion of each of the signals into an intermediate frequency signal. Then, the signal is fed to a signal intensity measurement circuit and sampled by a clock n (n: an integer) times as high as a chip frequency, resulting in an intensity thereof being measured. Depending on results of the measurement, a selection signal is fed to a path switching circuit, resulting in one of outputs of the receiver circuits being selected, which is then fed to a direct spread demodulation circuit.

Abstract: Broadcasting of data packets from a hub station to many remote terminals in a two-way data network uses a spread spectrum time division multiplexed (TDM) channel. A channel in the other direction is a multiple access channel. To provide substantially equal energy per bit of the received signal at each of the remote terminals for maintaining reliability per bit at all terminals, the spreading factor of number of chips per bit is increased according to the distance of the remote terminal from the hub or the strength of the signal from the hub received by the remote terminal. The spreading factor or number of chips per bit may be changed according to the strength of the signal received by the hub from the remote terminal. Terminals positioned around the hub transmitter are located in regions arbitrarily determined by signal strengths, terrain, weather conditions or range.

Abstract: A mobile station comprises a power detector, an averaging circuit, and a signal fade detector. The power detector measures a channel signal power (receive signal power) of a receive signal received by a receiver. The averaging circuit averages the receive signal power measured by the power detector. The signal fade detector detects the fade of the channel signal power with the average of the receive signal power. When the fade of the receive signal is detected, while a call request or a call response is being transmitted, after the receive signal power is recovered, a control circuit of the mobile station re-transmits the call request or the call response. When the fade of the receive signal is detected just before a call request or a call response is to be transmitted, the control circuit of the mobile station stops transmitting the call request or the call response. After the receive signal power is recovered, the control circuit of the mobile station transmits the call request or the call response.

Abstract: The present invention relates to a diversity method in a radio system in which fadeouts are slow, such as a WLL system. The duration of fadeouts is typically in the magnitude of seconds. A radio receiver (4) according to the present invention is characterized in that the expected quality of a signal is predicted (9) for a specific interval to come based on the measured quality of the signal, and a signal is selected (3) based on the predicted quality of the signal. In a time-divided digital system, the quality of a signal is measured from a burst and the quality of the signal is predicted for several frames ahead, for example for 10 frames, based on the measured quality of said burst and one or more bursts preceeding said burst. The predicted quality is compared with a long-term weighted average, which may be the average over 50 frames, for example. If the predicted quality is below the weighted average, the signal is changed.

Abstract: A method and system for accurately accounting for an amount of satellite communications system resources that are allotted to and utilized by a user terminal on a per call or connection basis. The method accumulates data at periodic intervals during a connection, the data indicating what portion of the overall system resources are utilized on both a forward link (gateway to satellite(s) to user terminal) and on a reverse link (user terminal to satellite(s) to gateway). The usage data can include power levels, data rates, user terminal location, and user terminal type. A Gateway (18) that is assigned to handling the call for the user terminal (13) accumulates the data and subsequently transfers the data over a terrestrial data network (39) to a Ground Operations Control Center (38). The center uses the data to determine an amount to be billed to a service provider associated with a service area that includes the gateway.

Abstract: A system and method for selecting and combining satellite communication signals from multiple antennas. The system includes at least two signal paths, each coupled to a separate antenna, and a combiner for combining signals from the two paths for processing by a signal processor. At least one of the two paths includes a signal delay unit. The signal processor can distinguish a signal received from a source on one of the antennas from that signal received from the source on the other antenna based on a signal delay produced by the signal delay unit. Each signal path includes a variable attenuator for selectively coupling each signal path to the signal processor. The signal processor determines the quality of the signals received along the signal paths, and provides data regarding signal quality to a control processor, which manipulates the attenuators to couple the signal path having the highest quality signal to the signal processor.

Abstract: A radio selective calling receiver includes a field strength detection unit for detecting a received field strength, a first time diversity processing section for performing time diversity processing with a large time diversity effect and large power consumption, a second time diversity processing section for performing time diversity processing with a small time diversity effect and small power consumption, and a selection unit for determining, on the basis of a detection result from the field strength detection unit, whether the received field strength is high or low, and selecting the first time diversity processing section for a low field strength or the second time diversity processing section for a high field strength.

Abstract: A selective call receiver that receives signals transmitted by orbiting satellites uses certain information transmitted by the satellites to calculate an estimate of its position. Using that estimate and other information, the selective call receiver is able to save power by disregarding certain information contained in transmitted signals that are not intended for it.

Abstract: A two-way satellite communications system includes an Earth station communicating with a plurality of remote terminals using a network access protocol that facilitates low power consumption by the terminals. The earth station generates forward link TDM packet data transmissions on one or-more satellite channels, and detects, despreads and decodes multiple concurrent return link slotted CDMA packet transmissions on one or more satellite channels. It communicates through a wired connection with a packet processing center which ultimately both delivers return link packet data to end-customers and receives forward link packet data from end-customers. The remote terminals receive, process and act upon forward link TDM transmissions on one or more satellite channels, and generate slotted spread spectrum CDMA transmissions on the return link on one or more satellite channels.

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 diversity receiver having a pair of receiving circuits, which is capable of disconnecting a faulty receiving circuit from its operation for preventing a communication quality from being degraded due to mis-selection of output signal of the faulty receiving circuit in a case of signal level being received is too low to discriminate between output signals of the faulty receiving circuit and the normal receiving circuit, is provided. The diversity receiver includes a first and second error rate accumulation circuits, each is coupled with corresponding receiver circuit, to accumulate error rate of each receiver circuit in a timing generated by a timing generator circuit. In combination of six judge circuits, first judge circuit to sixth judge circuits, and input of error accumulation value of each receiving circuit, it is judged whether or not there exist a fault in a receiving circuit and which receiving circuit is faulty.

Abstract: A radio communication system (5) includes transmitting unit (1) coupled to at least one controller (6). The controller (6) is adapted to combine message intervals (208) into a plurality of arrangements, each arrangement having a selected number of message intervals (208). An arrangement is then selected, and included in an acquisition group message. The arrangement is used for directing a number SCRs (selective call receivers) (2) targeted to receive the acquisition group message to monitor messages during the message reception interval (203) according to the arrangement. The controller (6) then invokes the transmitting unit (1) to transmit the acquisition group message to the SCRs (2). Messages targeted for specific SCR's (2) are then generated, and transmitted by way of transmitting unit (1) during the message reception interval (203) according to the arrangement selected. The targeted SCRs (2) intercept the messages according to the arrangement received in the acquisition group message.

Abstract: An elliptical satellite system which carries out communication. The satellite orbits a height above the earth less than that necessary for geosynchronous orbits. When the satellite is near the apogee portion of its orbit, its velocity approximates the rotational velocity of the earth, and during that period it appears to hover over the earth. Each ground station on the earth always communicates a satellite within a predetermined position of its apogee, and hence that satellite appears to the ground station to hover over the earth. The satellite hence does not communicate with any earth station when it is outside of that apogee portion. During the times when the satellite is outside the apogee portion, its communication is therefore shut off to prevent any possibility of interfering with geosynchronous satellites. During this time, the power supply on the satellite is also used to charge a battery on the satellite.

Abstract: A multivalued FSK demodulation window comparator includes an MSB comparator, an LSB comparator, a reception electric field strength detector, and a reference voltage generating circuit. The MSB comparator determines at least the polarity of a frequency shift of a radio frequency. The LSB comparator determines the absolute value of the frequency shift of the radio frequency. The reception electric field strength detector detects the strength of a radio signal and outputs a signal corresponding to the detected strength. The reference voltage generating circuit changes the reference voltages of the LSB comparator in accordance with an output voltage from the reception electric field strength detector. When the output voltage from the reception electric field strength detector is not higher than a predetermined level, a reference voltage from the reference voltage generating circuit changes.

Abstract: In an environment of competing satellite systems having in part shared bands/channel frequencies and at least one system having non-interfering dedicated bands/channels, interference between shared bands/channels of the two systems is mitigated by a method as recited in the appended claims, interference probabilities are determined and based on these probabilities and interference criteria to be met. Interference is minimized by making initial channel assignments to dedicated channels and assigning shared channels in accordance with traffic controls and limits are developed so as not to violate the interference criteria.

Abstract: The invention relates to a method for transmitting calls of different priorities in a cellular network which comprises in each cell at least one base station (10) communicating with subscriber terminals (11a-11d, 13) within its area, and in which network the base station transmits power control information to the terminal equipments, which may adjust their transmit power on the basis of the power control messages from the base station, the calls of the network having different levels of priority. In order to ensure the call establishment and the quality of calls with a high priority, the calls with a high priority use a higher transmit power than what is allowed for calls with a lower priority.

Abstract: A radio communication system (5) includes a transmitting unit (1) coupled to at least one controller (6). The controller (6) is adapted to subdivide the SCR's (selective call receivers) (2) into SCR groups, assign the SCR groups to supergroups, and assign a selected number of message frames (216) and message intervals (208) to each SCR group in each supergroup. A supergroup is then selected, and included in an acquisition group message. The supergroup is for directing SCR's (2) targeted to receive the acquisition group message to monitor messages during the message reception interval (203) according to the supergroup. The controller (6) then invokes the transmitting unit (1) to transmit the acquisition group message to the SCR's (2). Messages target for specific SCR's (2) are then generated, and transmitted by way of the transmitting unit (1) according to the supergroup selected. The targeted SCR's (2) receive the messages according to the supergroup received.

Abstract: A power control method and apparatus are provided for a satellite based telecommunications system. The system includes a power control subsystem which is operative with systems operations center for distributing available satellite power between earth stations. Each earth station includes a baseband manager which subdivides the available satellite power between subband beams emitted from the satellite. The earth station further includes beam processors which manage the power allocated to each subband within an associated beam in order to maintain a desired signal quality in a forward link between the satellite and user terminals within the associated subbands. The beam processors communicate with modems, each of which is assigned to a particular user terminal. Each modem controls the satellites transmission power in the forward link to the user terminals to maintain a desired signal-to-noise ratio at the user terminal receiver. The signal-to-noise ratio is determined by the corresponding beam processor.

Abstract: A method and associated circuitry for initiating communication between a network station and a user terminal of a radiotelephonic communication system, such as a satellite-cellular communication system. When communication is to be initiated, a paging signal is transmitted by a network station to the user terminal. When the user terminal detects the paging signal, an acknowledgment signal is generated by the user terminal and encoded to increase the margin of the acknowledgment signal. An increased-margin acknowledgment signal acknowledging reception of the paging signal is transmitted to facilitate communication of the acknowledgment signal back to the network station.

Abstract: A mean value of a received signal level is calculated by a mean value computing unit, a product of multiplying this received signal mean level by a prescribed ratio is calculated by a threshold computing unit and used as a first threshold value, and when the received signal level drops below this first threshold value, communication is performed by making a switch to an antenna that receives signals at a received signal level that is higher than the first threshold value. Switching of receiving antennas is not made when the received signal mean level calculated by the mean value computing unit falls below a second threshold value. This allows antenna switching to be performed in accordance with changes in the received signal level and prevents unnecessary antenna switching from being made when the level falls below the second threshold value.

Abstract: A quality dispatch service on a CDMA based wireless system. To achieve spectral efficiency and fast access for follow-up calls, in response to a request by a talkgroup member to have a group call established, the non-requesting (listening-only) members are allowed to establish a low-rate (non-voice) signaling link in the reverse direction (inbound) for the limited purpose of (i) providing forward power control information to the fixed infrastructure; (ii) requesting soft hand-off when required; and (iii) maintaining the correct reverse link power control to allow for fast channel access for a follow-on call. In accordance with the illustrative embodiment, the establishment of multiple inbound signaling links in a CDMA dispatch call occurs as a background process while beginning the voice communications immediately.

Abstract: A satellite-based, world-wide cellular messaging system (5) transmits paging messages to pagers (2) via multiple beams. A pager (2) monitors multiple beams, recording the schedules for each beam, and by combining the schedules for multiple beams, ultimately determines which frames in the message groups to monitor for messages. Pager (2), which conserves battery resources by entering into a sleep mode, synchronizes quickly to its message block when it awakes.

Abstract: A method for defining a radio frequency map to be used to isolate negative effects of undesirable radio frequency emitters on radio device communications handheld and stationary. The method includes the steps of measuring C-band power corresponding to an L-band beam as part of an L-band footprint of a communication satellite, calculating various identifiable interference errors associated with the signal transmission path, and subtracting the interference errors from the original C-band power measurement resulting in a power value corresponding to undesirable radio frequency emitter interference at the location of the L-band beam. The resultant radio frequency map can then be used to reallocate frequency channels of operation used by radio devices, mobile phones for example, resulting in power savings in the radio device while maintaining a suitable signal-to-noise ratio.

Abstract: A delayed detection MRC diversity circuit which does not adjust synchronization in every reception branch independently having a simple circuit constitution and superior receiving characteristics. The delayed detection MRC diversity circuit is composed of a comparison circuit for selecting a reception branch with maximum RSSI, a selector, a base band circuit such as synchronous circuit and so forth for generating a regenerative clock while adjusting bit-synchronization in terms of the reception branch with the maximum RSSI, and a MRC diversity circuit section for composing using the regenerative clock.

Abstract: A spacecraft includes a plurality of paralleled RF amplifiers. Each paralleled power amplifier (206) includes a signal splitter (222) which produces two nominally equal-amplitude signals, and a signal combiner (242) which combines appropriately phased signals to produce a sum signal at a sum port (250). The signal combiner also includes a null output port (248). A pair of elemental amplifiers (236, 238) is coupled between the splitter outputs and the combiner inputs. In order to allow for phase drift of the elemental amplifiers, at least one phase shifter (258) is associated with one of the elemental amplifiers. A phase control loop is coupled from the null output of the combiner, around the paralleled amplifier arrangement, and controls the phase shifter to maintain the phase within bounds, to maximize the signal at the sum port of the combiner.

Abstract: A self-steering antenna apparatus for receiving and transmitting electromagnetic signals, includes a plurality of antennas for receiving and emitting electromagnetic signals and a plurality of receivers for processing the received electromagnetic signals. Each one of the plurality of receivers corresponds to a respective one of the plurality of antennas. Each receiver provides signal strength information indicating a signal strength of the electromagnetic signal received by the corresponding antenna. A comparator compares the signal strength information provided by each receiver, and determines which of the antennas is receiving the strongest electromagnetic signal. Switching circuitry switches the received electromagnetic signals and the signals to be emitted, based on the comparison performed by the comparator, the switching circuitry selecting one of the plurality of antennas to emit and receive the electromagnetic signals based on the comparison.

Abstract: A method and system for controlling uplink power for signal transmission in a satellite communication system employing on-board demodulation and remodulation and having a plurality of user terminals that are linked by and that communicate with each other by way of a satellite relay system. A downlink error rate of the data in a downlink data stream is determined based on known data bits. An end-to-end error rate of the uplink data stream and the downlink data stream is determined. An error rate of the signal transmission is then determined based on the downlink error rate and the end-to-end error rate. The signal transmission is then controlled based on the error rate of the signal transmission.

Abstract: A transmitting apparatus for use in non-geostationary satellites which allows compliance with the restrictions placed on PFD even when the Earth is located between the geostationary satellite and the non-geostationary satellite. The transmitting apparatus 10 for use in non-geostationary satellites having a transmitting section 16 which sends a transmitting signal to the geostationary satellite, comprises an Earth-sensing section 19 for detecting the presence of the Earth in the direction of transmission and a transmission direction-shifting section 20 for shifting the direction of transmission of the transmitting signal in response to detection of the Earth-sensing section 19 to prevent the Earth from being exposed to the transmitting signal. Instead of the transmission direction-shifting section 20, there may be used a power supply-suspending section which automatically suspends power supply to the transmitting section 16 thereby stopping transmission of the transmitting signal.

Abstract: An elliptical satellite system which carries out communication. The satellite orbits a height above the earth less than that necessary for geosynchronous orbits. When the satellite is near the apogee portion of its orbit, its velocity approximates the rotational velocity of the earth, and during that period it appears to hover over the earth. Each ground station on the earth always communicates with a satellite within a predetermined position of its apogee, and hence that satellite appears to the ground station to hover over the earth. The satellite hence does not communicate with any earth station when it is outside of that apogee portion. During the times when the satellite is outside the apogee portion, its communication is therefore shut off to prevent any possibility of interfering with geosynchronous satellites. During this time, the power supply on the satellite is also used to charge a battery on the satellite.

Abstract: A method and system for demodulating received signals in radio communication systems. Pi/4-DQPSK modulated signals can be demodulated to provide additional quality measurements and to facilitate diversity combination or selection. For example, a carrier is modulated with digital data using Pi/4-DQPSK to convey two bits of data by changing the radio carrier phase from the value at the end of the last symbol through an angle of either .+-.45 degrees or .+-.135 degrees, these four possibilities representing the bit pairs 00, 01, 11 or 10. The transitions of the radio signal are filtered in the complex (I,Q) plane to limit the spectrum. At the receiver, the received signal is downconverted, filtered and amplified using a hard-limiting intermediate frequency (IF) amplifier. The IF amplifier also produces an approximately logarithmic indication of the signal strength before limiting. The hard-limited IF signal containing phase information is fed to a direct phase digitizer.

Abstract: A system and method for controlling the strength of a shared resource signal transmitted by the satellite transponder in a satellite communications system. The satellite communications system includes a gateway for transmitting communications signals including a shared resource signal, a satellite transponder for relaying the signals to at least one subscriber unit (for example, a phone), and at least one subscriber unit for receiving the signals. The method includes the steps of receiving the shared resource signal, at each subscriber unit, via the satellite transponder; measuring, at each subscriber unit, a signal strength for the received shared resource signal; sending the signal strengths to the gateway; and adjusting the power of the shared resource signal transmitted by the satellite transponder based on the signal strengths.

Abstract: A transmission power control method in a mobile satellite communication system implementing accurate control of transmission power of a base station by obtaining an average received signal level at a mobile station at high accuracy. The mobile station measures an average received signal level Q.sub.k in a predetermined period (step SP2), and informs the base station of the average received signal level Q.sub.k and an actual measuring time T.sub.k (step SP3). The base station calculates a total measuring time t.sub.k which is the sum total of the actual measuring time T.sub.k (step SP16), a corrected average received signal level R.sub.k associated with the average received signal level during the total measuring time t.sub.k (step SP18), and a measuring error .DELTA.D.sub.k (step SP17), and controls the transmission power on the basis of these values (step SP21). Estimating the measuring error .DELTA.D.sub.k in the total measuring time t.sub.k longer than the individual actual measuring time T.sub.

Abstract: A receiver configured to measure phase change (.DELTA..phi.) in a signal transmitted from a microwave signal source, such as a cell site for cellular telephones, the transmitted signal including a carrier signal (F.sub.1) added to a modulation signal (F.sub.MOD), the receiver providing the phase change measurement (.DELTA..phi.) without further reference to the modulation signal (F.sub.MOD). Utilizing (.DELTA..phi.), distance from the transmitter can be calculated. The receiver includes one or more mixers for receiving the transmitted signal from the cell site and downconverting relative to an intermediate frequency signal (F.sub.IF) to produce an IF mixed signal including a sum IF mixed signal (F.sub.IF +F.sub.MOD) and a difference IF mixed signal (F.sub.IF -F.sub.MOD). The receiver then further includes components to demodulate the IF mixed signal to provide the modulated signal (F.sub.MOD) and the phase change measurement (.DELTA..phi.) with tracking of the intermediate frequency signal (F.sub.IF).

Abstract: A control system for the uplink transmitter of a ground station communicating with a spacecraft includes an antenna located at the ground station, pointed toward the spacecraft for receiving downlink signals transmitted therefrom. The received signals are accompanied by noise attributable to ambient, sky and ground temperatures. A low-noise receiver is coupled to the output port of the antenna, for establishing the receiver noise temperature. A processor is coupled to the low-noise receiver apparatus and to the power control input port of the uplink transmitter, for responding to changes in the received noise power attributable to the presence or absence of precipitation in the downlink. The processor does this by producing an estimate of the attenuation attributable to the rain in the downlink, and generates the control signal in response to the estimate of the attenuation.

Abstract: The invention provides a method of regulating the power of transmission between first and second stations in a multiple satellite visibility satellite telecommunication network. The method comprises the following cyclic steps: regulation, for each of said N channels, of an isolated transmit power level command signal such that when it commands the power at which the first station transmits the first isolated signal in each channel the quality level of the corresponding isolated second signal received by the second station is equal to a reference quality level, and regulation, for all of the N channels, of N combined transmit power level command signals such that when they command the levels at which the first station respectively transmits the N first combined signals on the N channels the quality level of the global signal received formed from the N combined second signals is equal to the reference quality level.

Abstract: Disclosed is a method for operating a communications signal transmitter and apparatus for carrying out the method. The method includes the steps of receiving a communications signal; sensing an amount of user demand; adjusting an output of a power supply that supplies operating power to a communications signal transmitter amplifier in accordance with the sensed demand so as to increase the output of the power supply when the sensed demand increases and to decrease the output of the power supply when the sensed demand decreases; and amplifying the received communications signal with the communications signal transmitter amplifier.

Abstract: A method and system for increasing the signal margin of a radiocommunication link to provide a short message service which is reliable, even under non-ideal conditions. According to the method, short alphanumeric messages can be transmitted over the broadcast control channel of a digital radiocommunication link, or another communication channel consisting of one or more slots from successive frames in a TDMA communication link. An increase in transmission power is used in combination with repetition to increase effective signal margin without complications in the mobile unit design, significant delay, or co-channel interference. Where a more significant increase in signal margin is desired, when a longer message is required, or for voice messages, the message may be stored and the mobile unit alerted of the message.

Abstract: A method of determining parameters for the design of ground equipment for satellite link systems using duplex links is disclosed. The method has particular application to determining transponder power requirements and antenna size. The method comprises selecting required availability of the satellite system and ground sites for the equipment and determining site degradation parameters for the ground sites. A range where no up link power control is required is also determined and a point of minimum transponder power is determined to enable the parameters to be selected.

Abstract: A wireless telecommunications systems (1) includes a central terminal (10) for transmitting and receiving radio frequency signals to and from a subscriber terminal (20). A downlink communication path is established from a transmitter (200) of the central terminal (10) to a receiver (202) of the subscriber terminal (20). A downlink signal (212) is transmitted from the transmitter (200) to the receiver (202) during setup and operation of the wireless telecommunications system (1). The downlink signal (212) includes an overhead channel (224) having a power control signal (236). The power control signal (236) is capable of adjusting a transmitting power of a transmitter (204) in the subscriber terminal (20). Adjustment of the transmitting power of the transmitter (204) facilitates establishment and maintenance of an uplink communication path between the transmitter (204) of the subscriber terminal and a receiver (206) of the central terminal (10).

Abstract: An oscillation detecting apparatus for detecting an oscillation of a wireless repeater intervening between a base station and a mobile station brought in communication with each other through a TDMA system. The wireless repeater produces an input signal based on a radio wave transmitted from one of the base station and the mobile stations, and amplifies the input signal to produce an output signal. The output signal is transmitted from the wireless repeater to the other of the base station and the mobile station. The oscillation detecting apparatus comprises producing apparatus for producing a power level signal varied in proportion with an amplitude of the output signal. The power level signal is formed by, for example, an envelope of the output signal.

Abstract: A diversity receiver system includes reception circuits connected to antennas for converting frequency of a received signal to a base band signal; a diversity branch comparison circuit for directing a base band signal to be used by comparing an intermediate frequency supplied through the reception circuit; a base band delay detection circuit for outputting a detection signal which is generated by a delay detection of the base band signal directed by the diversity branch comparison circuit; and a DPLL circuit for generating an internal clock by using the detection signal supplied from the base band delay detection circuit, thereby securing a stable reception and providing a diversity receiver system having a small circuit scale.

Abstract: A system and method for reducing the risk of cellular phone loss, misplacement, and/or theft, the system including a wireless transmitter in a cell phone for intermittently sending security signals to a device (e.g. pager) to be worn by a user. The device includes an alarm which is actuated when either the strength or amplitude of the security signal(s) falls below a predetermined threshold or when such security signals are not received by the device (e.g. pager) for a predetermined period of time. Accordingly, the user is alerted to potential loss, misplacement, and/or theft of the cell phone.

Abstract: Disclosed is a method for operating a communications signal transmitter and apparatus for carrying out the method. The method includes the steps of receiving a communications signal; sensing a signal strength of the received communications signal, the signal strength being indicative of the current user demand; adjusting an output of a power supply that supplies operating power to a communications signal transmitter amplifier in accordance with the sensed signal strength so as to increase the output of the power supply when the sensed signal strength increases and to decrease the output of the power supply when the sensed signal strength decreases; and amplifying the received communications signal with the communications signal transmitter amplifier. The step of sensing may include a step of subtracting a noise component from the received communications signal.

Abstract: In a method and apparatus for maintaining a minimum transmission power level between two communication stations, each station measures the other's received signal quality, and returns an indication of signal quality as part of a regular maintenance burst. Each station adjusts its own transmission power level based on the returned signal quality indication. The signal quality indication is based on the received ratio of bit energy to total noise power spectral density which is calculated from an estimated bit-error-rate.

Abstract: In a satellite transponder architecture employing digital signal processing, a power monitor samples the data stream of carrier frequency samples on board the transponder and computes a power level for each of the carriers. This provides accurate and high frequency resolution power measurements within the communications link. These measurements are useful for computing critical transponder characteristics such as the effective isotropic radiated power (EIRP), receiver sensitivity, uplink sensitivity, operating points and, in a system using a phased array antenna, the total and component powers for each beam. The power monitor eliminates problems associated with external measurement methods, and improves the overall accuracy and reliability.

Abstract: For automatically monitoring to detect that a receiver of in a diversity receiver unit which includes at least two receivers having respective antennas, is operating deficiently, signal levels as received in a plurality of corresponding receptions by each receiver are averaged for each receiver, the averages are compared with one another, and, if the averages differ by more than a preselected limit, an indication of existence of malfunction is provided.