Abstract: A method is proposed that is used for terrestrial transmission of at least one digital signal, in particular a digital radio and/or TV broadcasting signal. In this method, the at least one digital signal, reduced in its data quantity by coding, is modulated, preferably by the OFDM method, and converted into the frequency position of at least one channel, adjacent to at least one occupied or unoccupied channel (30, 32) for transmitting an analog TV broadcasting signal, and is broadcast in this frequency position. The dynamic scope and the amplitude of the spectrum (41) of the at least one digital signal must undershoot a respectively predetermined value that is markedly less than the dynamic scope or amplitude of the video carrier of the spectrum (35, 36) of the analog TV broadcasting signal, so that there will be only slight intermodulation and cross modulation with other digital signals or with analog signals of other channels.

Abstract: In a device for communicating data between a base station having at least two transmit antennas, and a mobile station having at least one receive antenna in a mobile communication system, the device includes: a transmitter at the base station, for inserting power control bit (PCB) patterns into the data and sending the data with the PCB patterns inserted therein, the PCB patterns indicating one transmit antenna being used to transmit the data; and a receiver at the mobile station, for receiving the data, detecting the PCB patterns from the received data and determining the one transmit antenna from the detected PCB patterns.

Abstract: A device for linearizing transmitter amplifiers for transmitter equipment including a plurality of transmitters (11, 12, . . . 1n), each including a transmitter amplifier (4) and not totally decoupled from each other, said device including means for controlling the transmission of linearization signals relative to each amplifier and means (6) for analyzing the corresponding amplified linearization signals to determine the non-linearities of said amplifier and applying to wanted signals a pre-correction (5) to compensate said non-linearities, said device being essentially characterized in that it includes central control means (8, 8′, 10-20) for commanding the transmission of linearization signals relating to different transmitter amplifiers at different times.

Abstract: A transmitter for transmitting RF data in an RF communication network using a plurality of carrier frequencies is described. The transmitter has a data splitter for receiving an information signal at an intermediate frequency lower than the carrier frequency, and two transmitter paths each having an input connected to the data splitter and each having a frequency modulator for upconverting the intermediate frequency to a respective carrier frequency, the carrier frequency being individually selectable for each transmitter path.

Abstract: In a method and a device for reduction of intermodulation distortion in radio communication systems, a signal, which is intended to be transmitted, is fed to an active antenna for transmission in a main lobe. The antenna includes a plurality of transmitter stages each of which is supplied with a partial signal and includes an input stage, an amplifier, an output stage and an antenna element. A first phase rotation of each partial signal is performed before each amplifier, and a second phase rotation of each partial signal is performed after each amplifier. The sum of the first phase rotation and the second phase rotation is chosen to a value which is constant, and the second phase rotation is chosen so that an intermodulation lobe which is transmitted from the antenna is controlled in a direction which deviates substantially from the direction of said main lobe.

Abstract: A time division multiple access (TDMA) system radio equipment and a synthesizer output level adjusting circuit are disclosed for causing output level of synthesizer with frequency fluctuation caused by synthesizer switching to be variable in unnecessary guard time of transmission output and at the time transmission transient response by incorporating voltage variable attenuator into synthesizer output.

Abstract: A method of combining signals to a base station and combining signals in a radio network. The base station including an antenna, a modulating mechanism for generating and modulating carrier waves, and transmitters for generating signals that are modulated by the generated carrier waves. The signals are transmitted using an antenna. The modulating mechanism modulates two or more signals per generated carrier wave. The base station includes an amplification mechanism for amplifying the signals modulated by the carrier waves, and a mechanism configured to passively combine the signals modulated by the carrier waves to the same antenna after amplification.

Abstract: The invention relates to a method of implementing transceiver operation at a base station. In the method, at least two transmitter units (300, 302) in different sectors transmit signals at different frequencies to the same multifrequency amplifier (306), and the signals amplified by the multifrequency amplifier (306) are transmitted to a filter structure (500), which filters signals to be transmitted at different frequencies. In the method sector-specific antennas (418, 420) transmit and receive the signals at different frequencies and the filter structure (500) filters the at least two signals received at different frequencies. The filtered signals are transmitted via the filter unit (400) to the receiver amplifier (404), whereupon the signals received from the different sectors are transmitted to sector-specific receiver amplifiers (406, 408).

Abstract: An improvement in the design and deployment of collocated radio transceivers for highspeed wireless Internet access accomplished by increased isolation brought about by wrapping each transceiver in a shield of mild steel, enclosing collocated transceivers and associated equipment in non-reflective enclosures, use of low loss RF coaxial cables, and use of high isolation parabolic horn antennas.

Abstract: A signal amplification system involves transforming at least one signal to be amplified into at least one transformed signal which is amplified and the resulting amplified transformed signal(s) can be used to produce a version(s) of the at least one original signal. The at least one transformed signal can be produced from the at least one original signal by using the at least one original signal to amplitude and/or angle (phase or frequency) modulate the at least one original signal. After amplification of the at least one transformed signal, the resulting at least one amplified transformed signal is de-modulated to produce a version(s) of the at least one signal. In transforming the at least one original signal to produce the at least one transformed signal, the at least one original signal is transformed into a more desirable form, such as a more power efficient form, for amplification.

Abstract: A linear power amplifier arrangement is used for providing a selectable amount of amplification to a radio frequency signal to be amplified. The arrangement comprises a first parallel amplifier branch and a second parallel amplifier branch and means for conducting the radio frequency signal to be amplified selectably to one of the parallel amplifier branches. Additionally it comprises in the first parallel amplifier branch a series connection of a predistorter and a nonlinear amplifier, where said predistorter is arranged to compensate for the nonlinearity of said nonlinear amplifier.

Abstract: Received signal strength detecting means 109 and 110 detect received signal strength of the antennas of the respective terminals. A transmission antenna selector 111 selects an antenna with a maximum received signal strength with respect to the respective communication destinations, and when there is a plurality of communication destinations having the same antenna with a maximum received signal strength, the transmission antenna selector selects transmission antennas to be different from each other based on the received signal strength of the antennas with the second largest received signal strength, and an internal switch of a transmission antenna change device 114 is changed based on the selection result. This eliminates the need for providing mixers without reducing transmission diversity effect, and results in a reduction of a maximum output of a transmission amplifier.

Abstract: A radio communication system of this invention includes: terminals for sending a connection request through broadcast, detecting a reception condition when a connection request echo sent back is received as a terminal reception condition and sending it through broadcast; plural repeaters for detecting a reception condition when the connection request is received as a repeater reception condition, sending a connection request echo including this repeater reception condition and sending back a terminal reception condition echo to a master repeater when it receives a terminal reception condition; and a master repeater for when receiving the connection request echo and terminal reception condition, selecting a repeater securing an optimum communication state based on the repeater reception condition and terminal reception condition.

Abstract: An apparatus for communicating, over a single transmission medium, two signals of substantially the same center frequency. The apparatus offsets in frequency one of the signals by combining the signal with the signal from a local oscillator. The apparatus then transmits the two signals, one offset from the other, as well as the signal from the local oscillator to allow for recovery of the two signals with a precise correction for the offset. In particular, the transmission medium is an optical fiber and the two signals are a main RF signal and a diversity RF signal received, respectively, by a main element and a diversity element of a diversity antenna system. The invention is of use, for example, in providing to a microbase station a main RF signal and its diversity RF signal received at a diversity antenna system remote from the microbase station and connected to the microbase station by an optical fiber.

Abstract: An access point is provided for use in a wireless network having a system backbone and a plurality of mobile terminals. The access point includes a communication circuit coupling the access point to the system backbone, and a first transceiver for wirelessly communicating with at least one of the plurality of mobile terminals on a first communication channel. In addition, the access point includes a second transceiver for wirelessly communicating with at least another of the plurality of mobile terminals on a second communication channel different from the first communication channel.

Abstract: A system and method for determining dispersion of intermodulation power in a satellite communication system or any other system which can be mathematically modeled as a matrix multiplication followed by an instantaneous nonlinearity and another matrix multiplication include determining a matrix (V) representing amplitudes and frequencies of signals generated by a digital processor and input to a plurality of amplifiers. A matrix (M) representing signal propagation from the amplifiers to a destination is used to determine the intermodulation power at the destination within each transmitted beam at each intermodulation distortion frequency. The intermodulation distortion frequencies are determined based on sums and differences of component frequencies corresponding to the user signals.

Abstract: An apparatus and method for power control in a cellular basestation transmitter with multiple digital carrier channels. Each digital carrier signal is attenuated by a digital power control circuit under the control of a microcontroller, the amount of attenuation varying according to the number of active channels. The attenuated digital signals are combined and converted to an analog signal by a digital to analog converter, and the analog signal is amplified by an analog power control circuit also under control of the microcontroller. The combined digital signal may be clipped to reduce the signal peaks, the amount of clipping varying according to the number of active channels.

Abstract: A technique for converting a non-sectorized cell to a sectorized cell having multiple sectors utilizing a single broadband processing unit. The spectrum of a given frequency band having a center frequency ′&OHgr;o is divided into multiple bands (three, for example) having center frequencies ′&OHgr;o, ′&OHgr;o−&agr; and ′&OHgr;o+&agr;. In the receive path, respective sub-bands are used to convey analog RF signals from a subscriber in respective sectors to an associated transceiver. Each of the transceivers includes a front end for receiving incoming RF signals and an analog-to-digital converter for converting the analog signal to a digital data stream. The digital data streams from transceivers are combined, i.e., processed by digitally adding, and supplied to a single channelizer which, in turn, supplies the data to a TDM bus for transmission to a PSTN network.

Abstract: In a system for feeding electric power having a carrier band for a mobile communication base station including transmission power amplifiers and an array antenna, a transmission/reception system is capable of reducing a large loss which the transmission electric power suffers until the transmission electric power having a large output has been radiated into the air, and increase in the power consumption.

Abstract: A communications system that uses electromagnetic waves. The communications system preferably operates in the millimeter-wave frequencies, and provides relatively high signal restoration and isolation. The communications system can use polarization diversity to increase the capacity of a channel. Isolation and restoration features in the transceivers eliminate or reduce the effects of precipitation and/or reflection and diffraction from objects, and thus is well-suited for an urban environment. The transceiver will select the proper antenna and signal path for optimal information throughput as the conditions in the propagation medium of the network vary.

Abstract: A novel mobile satellite communications technique for hand-held terminals includes a satellite system having a plurality of individual satellites all in communication with a ground telecommunications hub. A signal processed by the ground telecommunications hub is radiated through multiple paths to a plurality of the individual satellites in the satellite constellation simultaneously. The radiated signal is then re-radiated by the plurality of individual satellites to a mobile satellite terminal that receives the re-radiated signal from the plurality of individual satellites simultaneously such that the same frequency spectrum may be re-used by another mobile user.

Abstract: A transmitter diversity assembly and an associated method for a radio transmitter. When coupled to a radio transmitter to form a portion thereof, signal diversity is created to overcome multi-path fading. A plurality of antennas are freely selectable to be coupled to receive bursts of a communication signal, modulated to be transmitted on any of selected carriers. By altering the carriers upon which the bursts of the communication signal are transmitted and the spatially-separated antennas used to transduce the bursts of the communication signal, both transmission space diversity and frequency diversity is created.

Abstract: The invention relates to a transmission blocker for mobile telephones as well a method for preventing transmission activities of mobile telephones in the vicinity of safety-relevant electronic devices, comprising a device for transmitting radio signals as interference signals in the frequency range of the relevant mobile radio network in such fashion that synchronization of the mobile telephone with a radio station and/or decoding of the information in the signaling channel and/or recognition of the relevant signals from the mobile radio network can be prevented.

Abstract: A radio frequency combining system is disclosed that uses commercially available quadrature hybrid couplers configured in a unique manner to combine any radio frequency sources such as transmitters into a single load such as an antenna. The radio frequency combining system is bidirectional and can be used in the receive mode to combine the output of a receive antenna with outputs from an interference canceller to then supply received signals to a multiple receiver system.

Abstract: This invention relates to a method and apparatus for transmitting a downlink signal from a communication station to one or more subscriber units to achieve a desired radiation level over a desired sector (e.g., everywhere), the communication station including an array of antenna elements and one or more signal processors programmed (in the case of programmable signal processors) to weight the downlink signal according to one of a sequence of complex valued weight vectors. The method includes sequentially repeating transmitting the downlink signal, each repetition with a different weight vector from the sequence until all weight vectors in the sequence have been transmitted with. The sequence is designed for achieving the desired radiation level during at least one of the repetitions. In this way, every user in the desired region is transmitted to in the time period.

Abstract: A transmitter provides a radio wave with selectable polarization. The transmitter includes antenna feeds that generate orthogonal radio waves having non-linear polarizations that corresponds to the selectable phase relationships of a first and a second modulating signals. A spacial combination of the non-linear radio waves to produce a linearly polarized radio wave that has an orientation corresponding to a selected phase relationship.

Abstract: A signal transmitting/receiving method and apparatus freed of the drawback of the conventional information multiplexing method (FDMA, TDMA or CDMA) that information multiplexing needs a bandwidth broader than the bandwidth of the original information, such that, if the bandwidth is scanty, the number of channels that can be accommodated is decreased. A signal transmission device 10 sends three different items of the transmission information, namely the transmission information items TA, TB and TC, from three transmitters 11A, 11B and 11C, by multiplexing communication via three different paths PA, PB and PC, using a transmission antenna unit 12. A signal receiving device 20 receives the three different information items TA, TB and TC, transmitted via three different paths PA, PB and PC, by receivers 22A, 22B, 22C, using a receiving antenna unit 21, for obtaining three different items of the reception information, namely the reception information items RA, RB and RC.

Abstract: A transmitter for a cellular phone comprising an antenna and being operable at a first radio frequency band and a second radio frequency band is disclosed. The transmitter comprises a first power amplifier and a second power amplifier, one of which is active at a time. The first power amplifier has an input for a first signal at the first radio frequency band, an input for a first control signal and a first output for an amplified first signal. The first output is connectable to the antenna. The second power amplifier has an input for a second signal at the second radio frequency band, an input for a second control signal and a second output for an amplified second signal. The second output is connectable to the antenna. The transmitter further comprises a single control module associated with the first and second outputs of the power amplifiers. The control module generates a control signal for the active power amplifier.

Abstract: A wireless telecommunications system base station architecture is disclosed that supports receive diversity, sectorization, and radio pooling without the need for a sniffer radio or a switching matrix between the radios and the receive antennas.

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: Disclosed is a transmitting diversity circuit for a TDMA radio unit which has: a plurality of antennas; a plurality of transmitting circuits; a plurality of receiving circuits; a first switch which is connected with one of the plurality of transmitting circuits and selects one of the plurality of antennas; a second switch which is connected with the first switch and selects the one or the other of the plurality of transmitting circuits; a third switch which is connected with the second switch and one or more of the plurality of receiving circuits and selects one of the plurality of transmitting circuits or the one or more of the plurality of receiving circuits; a judging circuit which controls the switching of the first and second switches according to a level of received field strength to be detected by the receiving circuit connected with the third switch; wherein the one of the plurality of transmitting circuits is connected through the first to third switches with the selected one of the plurality of ante

Abstract: It is to provide a multi-signal generator which is able to lower the cost thereof by performing modulation in a low frequency range and using an output of a frequency synthesizer commonly to all channels. The multi-signal generator for generating a multi-signal which is a combination of a plurality of output signals generated by a plurality of channels each of which is using a frequency conversion method wherein a modulated carrier signal and a local signal are frequency converted by a mixer, wherein an output frequency from at least one frequency synthesizer is commonly used as a frequency source for the carrier signal or local signal by all the channels.

Abstract: In a radio communication apparatus, a switch circuit is connected between a transmitter and first and second antennas. A control circuit is connected to the first antenna and the switch circuit and controls the switch circuit in accordance with a standing wave ratio measured from the first antenna. That is, when the standing wave ratio of the first antenna exceeds a predetermined value, the connection between the transmitter and the first antenna is switched to the connection between the transmitter and the second antenna.

Abstract: The new signal amplifiers dynamically adjust based on the signal's power level. When used on multi-beam satellites, increased signal power indicates an increase in traffic on the channel. The power level of the input signal is sensed and converted to a DC signal, which is applied to a control terminal of a power supply that regulates DC power supplied to the amplifier. During periods of increased traffic, an increase in system power is allocated to the channel. By monitoring traffic on a plurality of channels, available onboard power is allocated based upon the relative channel requirements. The sensed power of multiple channels is summed and scaled to determine the power requirement of the channel relative to the other channels. A command voltage received from a ground station may be switched in place of the summed voltage to allow amplification levels to be controlled from the ground station.

Abstract: A transmitter circuit for use in a mobile radio using both a normal frequency transmission band and a talk-around frequency transmission band is disclosed. The transmitter employs a local oscillator in the modulation circuit that operates at only a single frequency band characteristic. At the output of the modulation circuit, one of two transmission paths is selected by an RF switch. In the normal transmission path, the input signal is output in the normal frequency band. Alternatively, in the talk-around transmission path, the input signal is modulated to the talk-around frequency band and then output. The present circuitry eliminates the requirement for local oscillators having dual operational characteristics.

Abstract: A wireless telephone equipment is provided with a microphone for receiving voice of a user and changing the voice to audio signals of an outgoing call, a cellular transmitter for modulating a carrier with the audio signals in a cellular communication, a cellular band-pass filter for filtering the carrier modulated in the cellular transmitter, a cordless transmitter for modulating a carrier with the audio signals in a cordless communication, a cordless band-pass filter for filtering the carrier modulated in the cordless transmitter, an antenna for transmitting the carrier filtered in the cellular or cordless band-pass filter and receiving a modulated signal, a band-pass filter for filtering the modulated signal, a cellular-cordless receiver for demodulating the modulated signal filtered to reproduce audio signals of an incoming call in the cellular communication and cordless communication, and a speaker for receiving the audio signals of the incoming call and giving voice.

Abstract: A method and apparatus of combining carrier signals (110, 111) includes in a coupler (125) phase shifting signals (110, 111) by substantially 90 degrees to produce phase shifted signals (120, 121), coupling signals (110, 121) to produce a coupled signal (130) and the signals (111, 120) to produce a coupled signal (140). In phase shifters (450, 460), the coupled signals (130, 140) are independently phase shifted according to two independent frequency selective phase shifting functions (150, 160) to produce phase shifted coupled signals (170, 180) which are combined at combiner (190) to produce a combined carrier signal (199). A phase shifting attribute of functions (150, 160) is divided over predetermined frequency bands (210, 220, 230). Over the frequency bands (210) phase shift (260) leads phase shift (250) and lags over the frequency band (230) by substantially 90 degrees.

Abstract: A multi-carrier radio system in which pairs of subcarriers are positioned in frequency such that each subcarrier in a pair is the image of the other subcarrier in the pair. By making each subcarrier the image of another subcarrier, the radio system of the present invention permits highly integrated low-IF transceiver implementation. In an exemplary embodiment, a multi-carrier transceiver includes an integrated receiver comprising a first mixer for mixing an input signal with a local oscillator signal to produce an in-phase downconverted signal. Additionally, a first phase shifter phase-shifts the local oscillator signal to produce a quadrature local oscillator signal, and a second mixer mixes the input signal with the quadrature local oscillator signal to produce a quadrature downconverted signal. Thereafter, a second phase shifter phase-shifts, or rotates, the quadrature downconverted signal to produce a rotated quadrature downconverted signal.

Abstract: A method an apparatus for controlling frequency of a multi-channel transmitter. A reference frequency is generated and emitted to a thermally stable frequency discriminator. The thermally stable frequency discriminator emits a dc voltage to a plurality of individual oscillators. The individual oscillators in continuous wave mode or modulated by baseband signals are combined into a multi-channel signal at an intermediate range of frequencies. The multi-channel intermediate range of frequencies are preferably amplified and emitted as an output signal. At relatively lower frequencies, such as 4-6 GHz, up-conversion of the output signal is not necessary. At relatively higher frequencies, an up-converter can be used to employ a second thermally stable frequency discriminator.

Abstract: A multiple antenna cellular network communicates with a mobile station over a plurality of antennas. The antennas are arranged in a plurality of positions to customize a cell or cells. A transceiver is coupled to the antennas and configured to receive inbound information from the mobile station and transmit outbound information to the mobile station. A processor is coupled to the transceiver and configured to decode the inbound information and to encode the outbound information to communicate with the mobile station. In another embodiment, the antennas are similarly deployed to create a cell or cells. The transmit signal power is continuously modified to improve quality and to move the nulls so that a fixed location user can receive a high quality signal. Exemplary embodiments are provided for use with the Global Systems for Mobile Communication (GSM) protocol and can be applied to other digital technologies.

Abstract: A wireless speaker system that transmits and receives both analog and digital audio signals simultaneously over a single channel at frequencies above 900 MHz. The present invention advantageously uses continuously variable slope delta (CVSD) modulation to perform analog-to-digital (A/D) and digital-to-analog (D/A) conversion of audio signals in the transmitter and receiver, respectively, using complementary filters and CVSD modulation circuits in both the transmitter and receiver. Analog signals are modulated in the transmitter with a high-frequency carrier and band-pass filtered before being combined with the digitized audio signal to modulate a high-frequency carrier, i.e. over 900 MHz, which is transmitted to the receiver. Similarly, the receiver band-pass filters and demodulates the received signal to recover the analog signal components.

Abstract: A multicarrier transmission system (100) routes data symbols from a data source (142) to a multicarrier modulator (145). Each modulator (201, 202, 203) within the multicarrier modulator (145) is coupled to a corresponding gain adjuster (211, 212, 213) that distributes the available transmit power across various subcarriers. Power distribution, is determined in part, upon the noise sensitivity of the transmitted information. In accordance, data stream symbols of like sensitivity are grouped (520) and transmitted during defined time intervals. Each such group is assigned a unique transmission power level (530). At any given moment in time, all subcarrier transmission power levels will have an identical amplitude, thereby mitigating the impact of subchannel-to-subchannel interference.

Abstract: A communications system achieves high bit rates over an actual communications channel between M transmitter antennas of a first unit and N receiver antennas of a second unit, where M or N>1, by creating virtual sub-channels from the actual communications channel. The multiple antenna system creates the virtual sub-channels from the actual communications channel by using propagation information characterizing the actual communications channel at the first and second units. For transmissions from the first unit to the second unit, the first unit sends a virtual transmitted signal over at least a subset of the virtual sub-channels using at least a portion of the propagation information. The second unit retrieves a corresponding virtual received signal from the same set of virtual sub-channels using at least another portion of said propagation information.

Abstract: An FM transmitter includes I and Q channels, each deriving a baseband sinusoidal wave having a frequency determined by speech and/or music broadcast information amplitude and nominally having the same maximum amplitude. Each wave drives a different balanced mixer, each responsive to orthogonally phased carrier waves. Outputs of the mixers are added to derive a frequency modulated output wave. The channels, mixers, and circuitry associated with them tend to introduce unwanted components in the output wave. Offset, peak amplitude, phase and relative delay of the added mixed outputs are such that the unwanted components are substantially eliminated from the output wave. The sinusoidal waves are derived by DACs responsive to signals derived by a digital processor having a memory storing amplitude vs. phase position values and slope vs. phase position values that are combined in response to samples of the broadcast information.

Abstract: The present invention relates to a power amplifier device (10), switchable for at least two separate basic frequency bands, for radio frequency signals with effective suppression of harmonics, where harmonics, corresponding to a first basic frequency band, can be permitted to overlap the frequency range of at least one second basic frequency band. The power amplifier device (10) comprises a power amplifier (1) and an impedance matching circuit (2), switchable by means of a PIN-diode, which provides a load impedance adapted to each individual basic frequency band. Furthermore, the power amplifier device comprises a filter device (3) comprising a fixed low-pass filter (3b) and a switchable filter (3b) acting as an engageable and disengageable notch filter, which comprises at least one reversible PIN-diode.

Abstract: A transmitter diversity assembly and an associated method for a radio transmitter. When coupled to a radio transmitter to form a portion thereof, signal diversity is created to overcome multi-path fading. A plurality of antennas are freely selectable to be coupled to receive bursts of a communication signal, modulated to be transmitted on any of selected carriers. By altering the carriers upon which the bursts of the communication signal are transmitted and the spatially-separated antennas used to transduce the bursts of the communication signal, both transmission space diversity and frequency diversity is created.

Abstract: A scanning and targeting system (100) interconnects a plurality of radio channel units (203) in a single trunk group with a plurality of antennas (202), each radio channel unit (203) having a receive section and a transmit section and the scanning and targeting system dynamically connecting the receive section of each one of the radio channel units with any one of the plurality of antennas which, on average during a sampling period, has the strongest received signal strength of RF signals at the operating frequency of the radio channel unit, and the scanning and targeting system dynamically interconnecting the transmit section of each of the plurality of radio channel units with any one of the plurality of antennas which, on average during the sampling period, is best suited for transmitting RF signals at the operating frequency of the radio channel unit in a direction corresponding to the desired destination for the transmitted RF signals.

Abstract: A base station arrangement for a cellular radio system comprising an antenna array, is disclosed. The downlink signals transmitted from antennas have a spacing which is scaled in proportion to the transmitted and received wavelengths. A method of operation is also disclosed.

Abstract: A transceiver switching apparatus and method for maintenance and repair of a troubled transceiver in a cellular base station in a CDMA mobile telecommunication system. The apparatus has a switching module having a plurality of switches in combination, capable of simultaneous control of the switches with a single control signal.

Abstract: In a method for controlling transmission band, minimum intervals are provided for a plurality of signal sources, respectively, so that each of the signal sources turns into a condition where a signal can be transmitted therefrom when the minimum interval thereof is elapsed. The minimum interval for each of the signal sources is counted since the last signal is transmitted therefrom. A waiting time for each of the signal sources is counted since the minimum interval thereof is elapsed. One signal source is selected from the signal sources whose waiting time is the longest so that the selected signal source transmits a signal to the common transmission line. The minimum interval and the waiting time for the selected signal source are renewed in accordance with the time-slot interval and the waiting time thereof.