Abstract: Methods and base stations for controlling downlink power, especially in systems employing virtual cells, are described. By providing attenuators in each transmit signal processing chain, e.g., after upconverting to intermediate frequencies, downlink power control can be more finely tuned to different antenna elements.

Abstract: A method and system for reducing local oscillator leakage from radio frequency mixers is disclosed. Compensating circuits are used to reduce or eliminate unwanted leakage from the mixer output signal by controlling the current in individual branches of a balanced input circuit of the mixer. The current is directly controlled by adjusting the voltage on the bases of the differential type amplifier input transistors, or by injecting current directly into the individual branches, or by extracting current directly from the individual branches. The current is also indirectly controlled by increasing the temperature of the mixer components with power dissipation elements that are not connected to the mixer. The compensating circuits are made of different combinations of resistor, transistor and current sink components.

Abstract: A receiver includes at least two intermediate frequency (IF) filters, with the first IF filter and a second filter having a narrower bandwidth than the first bandwidth. The receiver also includes a switch operable to select between the IF filters. In use, the receiver measures the signal strength of adjacent channels to the signal strength of a desired channel and switches to the second IF filter with a narrower bandwidth when a ratio of the signal strength of the channel and the signal strength of adjacent channels is less than a predetermined threshold. The predetermined threshold is determined based on considerations of range of detection and adjacent channel interference. The bandwidth of the filters in the receiver is also designed to optimize performance in consideration of both range of detection and adjacent channel interference.

Abstract: A communication system is disclosed having a mobile unit connectable to different networks. The mobile unit is subscribed to a subscriber network which is one of these different networks. The mobile unit is connected to the subscriber network when establishing a call. The mobile unit includes an analysis circuit for producing data related to the different networks. A communication circuit of the mobile unit communicates the data to a user for selecting an optimal network from the different networks to establish a call. The data includes time periods the mobile unit is synchronized to each of the different networks. The optimal network has the longest synchronized time period or the lowest cost.

Abstract: A method for storing the data of a received carrier frequency of a radio transmitter, and/or of the evaluation of its reception, in a data memory of a radio receiver. In the method, the regional identifier is detached from the particular PI code received with the carrier frequency; and the remaining main portion of the PI code, the detached regional identifier, and lastly the received carrier frequency are respectively written into empty locations, existing or to be created, between the stored data, arranged in ascending order, of other carrier frequencies, if the data are not already stored.

Abstract: An antenna switch for selectively connecting an output differential signal pair of an output power amplifier to a single-ended signal of an antenna when transmitting and selectively connecting an input differential signal pair of a low noise input amplifier to the single-ended signal of the antenna when receiving. A first balun having a single ended-signal connected to an antenna connects a first and second output differential signal to a power output amplifier. A second balun having a single-ended signal connected to the antenna connects a first and second input differential signal to a low noise input amplifier. A first diode selectively shorts the first output differential signal to the second output differential signal of the first balun when receiving and a second diode selectively shorts the first input differential signal to the second input differential signal of the second balun when transmitting.

Abstract: A variable phase shift network (420) for a phase quadrature signal generator (320, 370) includes a variable current controller (909), a first NPN transistor (801) and a second NPN transistor (802). The variable phase shift network (420) produces a first quadrature input signal (830), a second quadrature input signal (834), a first quadrature output signal (821) and a second quadrature output signal (826) responsive to receiving a first differential input signal (919) and a second differential input signal (925).

Abstract: A radio receiver with isolation between an antenna and a regenerative oscillator/detector. The isolation is provided by periodically (at the receiver's quench frequency) uncoupling the antenna from the regenerative oscillator/detector. The receiver preferably includes an antenna, a super-regenerative oscillator/detector, a clock that indicates the quench frequency, a timing circuit coupled to the clock, and a switch coupled to the antenna, to the oscillator/detector, and to the timing circuit. The timing circuit specifies a first part and a second part of each clock period. During the first part of each clock period, the switch at least partially couples the antenna to the oscillator/detector on the nominal reception frequency. During the second part of each clock period, the switch at least partially uncouples these two elements on the nominal reception frequency.

Abstract: A first mobile station within a particular service area is initially allocated with a full-rate traffic channel. When congestion occurs within the serving base station controller (BSC) and no traffic channel is available for further allocation, the full-rate traffic channel previously allocated to the first mobile station is divided into two half-rate channels. The first mobile station is thereafter re-allocated to one of the two half-rate channels by an intra-cell handover or mode modify procedure. The other half-rate traffic channel then becomes available to effectuate a new call connection with a second mobile station and increases the call capacity associated with the serving BSC.

Abstract: A transmission/reception apparatus consists of a transmitter section including a gain amplifier which amplifies a gain of the transmission signal, power amplifier which amplifies the output of the gain amplifier, and transmission monitor signal extractor which extracts a transmission monitor signal from the transmission signal produced by the power amplifier, a receiver section including a coupler which couples the output of the transmission monitor signal extractor to the reception signal, low-noise amplifier which amplifies the output of the coupler, and separator which separates the output of the low-noise amplifier, and a controller including at least a gain controller which controls the gain amplifier based on a prescribed control reference and the output of the separator. The apparatus is capable of controlling the transmission output in a wide range by amplifying a weak transmission monitor signal in the receiver section.

Abstract: An input unit enters two reference signals having respective different frequencies at a stage preceding a power amplifier. The reference signals are delivered through a predistortion circuit to a power amplifier, and supplied from a predetermined section of the power amplifier. The signals from the power amplifier contain a third-order intermodulation distortion component. Based on the signals from the power amplifier, an extracting unit extracts a frequency component having a frequency which is twice the difference between the frequencies of said two reference signals. A detecting unit detects the extracted frequency component thereby to output a DC voltage. Since the extracted frequency component is correlated to the third-order intermodulation distortion component, the DC voltage represents the magnitude of the third-order inter-modulation distortion component.