Abstract: A mobile communication system employs moving base stations moving in the direction of flow of traffic moving along a roadway. The moving base station communicates with fixed radio ports connected to a gateway office. A plurality of moving base stations are spaced apart on a closed loop and move with the flow of traffic along one roadway on one leg of the loop and with a flow of traffic on another roadway in another leg of the loop. The moving base stations communicate with a plurality of fixed radio ports connected by a signal transmission link to a gateway office which, in turn, is connected to the wire line network. The moving base stations are each provided with a pair of directional antennas with one antenna directed toward the flow of traffic and another antenna directed to the fixed radio ports.

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: The invention relates to portable mobile communication device. The system according to the invention measures the power transmitted by the mobile communication device and the reflected power returning from the antenna. From these, the system calculates various parameters, for example, the short-term average value, the cumulative sum of transmitted power used during a call and the proportion of power reflected back. The user may set the limit values which he requires for these parameters, and the system will issue an alarm when these are exceeded. If the user so desires, the system may also continuously display the value of a desired quantity. With the aid of the system according to this invention, the user may monitor the benefit of different positions and ways in which the appliance is used and the power consumption of the mobile communication device in different situations, and thus avoid unfavorable operating situations and methods.

Abstract: The object of the present invention is to provide a radio communication system capable of following change in fading. To attain the object, the transmitter in the radio communication system according to the present invention predicts the state of fading after the specified period of time based on the fading state signal indicative of state of fading at current time notified by the receiver, thereby amplifies the transmission signal in accordance with the predicted state of fading.

Abstract: An on-board aircraft telecommunication exchange (32) provides communication and authentication services for M subscriber identity modules (SIMs) using N transceivers (36), where M can be greater than N. Associations between SIMs (56) and transceivers (36) are established when needed. Accordingly, a pool of transceivers 36 is provided to serve the collective needs of many subscribers. A SIM-based authentication process is performed (100) using a subscriber's original SIM (56). That authentication can be extended to a temporary SIM (106) that is substituted for the original SIM throughout the remainder of a flight. Alternatively, the original SIMs (56) may be locked in place and relinquished when a subscriber provides an appropriate PIN.

Abstract: A radio transmission/reception system using the same frequency includes a power control circuit which can prevent a sensitivity of the receiver from being lowered due to the carrier radiated from the transmitter, and finely control the power. The power control circuit includes first and second variable attenuators being respectively installed at an intermediate frequency stage and a local oscillator frequency stage, so as to finely control the power level of a next radio frequency stage. A CPU (central processing unit) controls amounts of attenuation of the first and second variable attenuators.