Arrangement and a method relating to a radio unit

A radio unit for communication with radio terminals comprising:

• at least one remote transmitter amplifier unit having an input and an output, wherein the input of the transmitter amplifier unit is connected to a transmitter-and-receiver unit in the radio unit by a feeder having time-varying attenuation, wherein the output of the transmitter amplifier unit is connected to an antenna unit, wherein the transmitter amplifier unit includes a first variable amplifier;
• a second variable amplifier having an input and an output, wherein the output of the second variable amplifier is connected to said transmitter-and-receiver unit via said feeder, and wherein the input of the second variable amplifier is connected to said antenna unit;
• at least one sensor means for generating a detector signal corresponding to the signal output power of said antenna unit;
• a difference amplifier for comparing said detector signal with a reference signal corresponding to a desired signal output power, wherein a difference signal is obtained on an output of the difference amplifier, and wherein the output of the difference amplifier is connected at least to said first variable amplifier, and wherein said difference signal is used to control said first variable amplifier to compensate for said varying attenuation in the feeder;
• and
• at least one remote receiver amplifier unit having an input and an output, wherein the antenna unit includes a first and second antenna, wherein the output of the at least one transmitter amplifier unit is connected to said first antenna, wherein the input of the receiver amplifier unit is connected to said second antenna, wherein the output of the receiver amplifier unit is connected to said transmitter-and-receiver unit in the radio unit via said feeder, wherein said receiver amplifier unit includes said second variable amplifier, and wherein said difference signal controls the second variable amplifier to compensate for said varying attenuation in the feeder.

A radio unit, for communication with radio terminals, comprising:

• a first and a second communications unit, each of which includes a respective antenna, wherein the first communications unit includes a first sensing means and the second communications unit includes a second sensing means;
• said first and said second sensing means each being adapted to generate a respective detector signal corresponding to the power output of its own antenna;
• wherein the first communications unit also includes a first remote transmitter amplifier unit and said second communications unit also includes a second remote transmitter amplifier unit, each of said amplifier units having an input and an output, wherein the input is connected to a respective transmitter-receiver unit in said radio unit via a respective feeder having an attenuation that varies in time, and wherein said output is connected to its respective antenna, and wherein said first and said second transmitter amplifier units, each includes a respective variable amplifier;
• and
• a difference amplifier having an input from said first sensing means, an input from said second sensing means, wherein the difference amplifier is adapted to compare said detector signal from said first and said second sensing means with a reference signal that corresponds to a desired output power, and wherein a difference signal is obtained on an output of the difference amplifier, wherein
• the output of the difference amplifier is connected to each of said variable amplifiers of said communications units, and
• the difference signal is used to control said variable amplifiers to compensate for said varying attenuation in respective feeders.

A radio unit comprising:

• at least two communications units, wherein each communication unit comprises:
• a power amplifier in series with a variable amplifier;
• a transmitter-and-receiver unit;
• a feeder having a time-varying attenuation;
• and
• an antenna, wherein said power amplifier and said variable amplifier are disposed between said antenna and said transmitter-and-receiver unit via said feeder;
• a sensing means which is adapted to generate a detector signal corresponding to the output power of said antenna;
• a difference amplifier for comparing said detector signal with a reference signal that corresponds to a desired power output, and wherein a difference signal is obtained on the output of the difference amplifier, wherein the output of the difference amplifier is connected to the variable amplifier, and said difference signal is used to control said variable amplifier to compensate for said varying attenuation in the feeder;
• a supervisory unit located adjacent said transmitter-receiver units;
• and
• an antenna unit including a control unit connected to each difference amplifier and to the transmitter-receiver unit.

A radio unit comprising:

• a transmitter-and-receiver unit;
• an antenna unit;
• and
• a feeder with a time-varying attenuation, wherein the feeder connects the transmitter-and-receiver unit to the antenna unit, via a circulator;
• the antenna unit comprising:
• an antenna connected to a remote transmitter amplifier unit, via a duplex filter, wherein the remote transmitter amplifier unit comprises a variable amplifier and a power amplifier used to compensate for the time-varying attenuation in the feeder;
• a control circuit, the control circuit comprising;
• a sensor means for generating a detector signal corresponding to a signal output power of the antenna;
• and
• a difference amplifier for comparing the detector signal with a reference signal corresponding to a desired signal output power, wherein the difference amplifier generates a difference signal for use by the variable amplifier of the remote transmitter amplifier unit;
• and
• a remote receiver amplifier unit connected to the antenna, via the duplex filter, and the feeder, via the circulator, wherein the remote receiver amplifier unit comprises a second variable amplifier and a second power amplifier used to compensate for the time-varying attenuation in the feeder, and wherein the difference signal generated from the difference amplifier in the antenna unit is connected to the second variable amplifier of the remote receiver amplifier unit.