An apparatus and method for an interface for transmitting high speed data between circuits. A driver circuit produces first and second differential currents from a digital signal that drive first and second transmission lines. A receiver is connected through first and second terminating resistors to said transmission lines. The resistive elements are in turn connected to first and second common base amplifiers where the differential currents are converted to a differential voltage. The input impedance to the first and second common-base amplifiers is further lowered by a differential amplifier having inputs connected to the inputs of the common-base amplifiers, and an output connected to the bases of said common-base amplifiers. As a result, voltage conversion of the differential signals takes place in the common-base amplifiers and not in the terminating resistors, reducing the level of the differential currents and permitting an increase in the digital data rate. In addition, a common-gate amplifier configuration of the present invention is provided as well as a method for dynamically determining an optimal transmit power level for the driver circuit and for performing an accelerated bit error rate measurement.

A base station controller and method for controlling a forward link power level in a CDMA cellular system provides an adjustment threshold. The method includes the steps of defining the adjustment threshold for the forward link power level, and receiving an inner-loop power control command from a remote transmitter. The power control command defines a request for an incremental adjustment in the forward link power level. The method further provides for defining the forward link power level based on the adjustment threshold and the request. Tracking a cumulative power adjustment of the forward link power level allows the base station controller to avoid continuous increases in transmitted power when the power commands are actually the result of multipath effects. The result is an improvement in overall cell operation.

An outer loop power control apparatus and method in a mobile communication system are disclosed. If a first received frame has no errors and the raw BER of the first received frame is equal to or greater than a predetermined raw BER, a power control mode is changed to an adjustment mode. If a second received frame following the first received frame has no errors and the raw BER of the second received frame is less than the threshold raw BER in the adjustment mode, a target Eb/No is decreased by a product of a first step coefficient and a decrement unit. If the raw BER of the second received frame is equal to or greater than the threshold raw BER, the raw BERs of the first and second received frames are compared. If the raw BER of the second received frame is less than the raw BER of the first received frame, the target Eb/No is decreased by a product of a second step coefficient and the decrement unit.

The object is to control interference in a permissible range by applying the CDMA system to signal collision in the conventional CSMA and TDMA base multihop systems and to relax the hidden terminal problem and others to enhance the throughput of the entire system by grouping of channel groups in multihop transmission and by control of transmission based on an interference level from another station. A multihop relay station calculates a desired signal level, for example, from an interference level at its own station of a packet sent from a mobile station, and notifies the mobile station of the desired signal level; and the mobile station calculates a transmission power amount of a packet from the desired signal level, determines whether the packet is transmissible to the station as a source of the desired signal level, and transmits the packet to the source station determined as a packet-transmissible station.

A forward power controlling apparatus in a CDMA mobile communication system is provided. In the forward power controlling apparatus, an SIR measurer measures the SIR of each received frame on a forward user channel using all the demodulated symbols of the frame, a symbol rate detector detects symbol rate information inserted in a predetermined position of the frame, and a controller changes a threshold according to the detected symbol rate information, compares the threshold with the SIR, and generates a forward power control command.