Method and arrangement for transmitting and receiving RF signals through various radio interfaces of communication systems

Patent metadata

Field	Value
Publication number	US-9270301-B2
Application number	US-201414272820-A
Country	US
Kind code	B2
Filing date	May 8, 2014
Priority date	Nov 26, 1998
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A method and arrangement for transmitting and receiving RF signals, associated with different radio interfaces of communication systems, employ a direct conversion based transceiver which substantially comprises one receive signal branch and one transmit signal branch. Mixing frequencies of the different systems are generated by a single common by use of an output frequency divider in combination with the synthesizer, and by use of filtering corresponding to a system channel bandwidth by means of a controllable low-pass filter operating at baseband frequency.

First claim

The invention claimed is:

1. A direct-conversion transceiver capable of operating with a plurality of radio interfaces, comprising:
a first controllable bandpass filter configured to filter a received signal according to a first bandpass control signal that selects one of a plurality of passbands corresponding to a selected one of the plurality of radio interfaces, wherein the first controllable bandpass filter has a signal path common to the plurality of radio interfaces;
a low-noise amplifier configured to amplify the filtered received signal according to a first gain control signal that controls an amount of gain, wherein the low-noise amplifier has a signal path common to the plurality of radio interfaces;
a first programmable synthesizer configured to generate a first mixing signal according to a first mixing control signal corresponding to the selected one of the plurality of radio interfaces, wherein the first programmable synthesizer has a signal path common to the plurality of radio interfaces;
a first frequency divider coupled to the first programmable synthesizer and configured to divide a frequency of the first mixing signal by two to provide a first divided frequency signal according to a first divider control signal corresponding to the selected one of plurality of radio interfaces;
a first mixer coupled to the low-noise amplifier and configured to mix the amplified and filtered received signal with the first divided mixing signal to produce a first baseband quadrature signal, wherein the first mixer has a signal path common to the plurality of radio interfaces and wherein the first mixer produces the first baseband quadrature signal on a basis of two 90-degree phase-shifted components produced from the first frequency divider;
a first low-pass filter coupled to the first mixer and configured to low-pass filter the first baseband quadrature signal according to a first filter control signal corresponding to the selected one of the plurality of radio interfaces, wherein the first low-pass filter has a signal path common to the plurality of radio interfaces;
a first gain-controlled amplifier coupled to the first low-pass filter and configured to provide gain-controlled amplification of the first low-pass filtered baseband quadrature signal, wherein the first gain-controlled amplifier has a signal path common to the plurality of radio interfaces;
an analog-to-digital converter coupled to the first gain-controlled amplifier and configured to convert to digital form an output of the first gain-controlled amplifier;
a digital signal processor configured to receive digital output from the analog-to-digital converter and to further process said digital output;
a digital-to-analog converter coupled to the digital signal processor and configured to receive a second baseband quadrature signal therefrom and to provide analog output signals;
a second low-pass filter coupled to the digital-to-analog converter and configured to low-pass filter the analog output signals from the digital-to-analog converter according to a second filter control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second low-pass filter has a signal path common to the plurality of radio interfaces;
a second programmable synthesizer configured to generate a second mixing signal according to a second mixing control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second programmable synthesizer has a signal path common to the plurality of radio interfaces;
a second frequency divider coupled to the second programmable synthesizer and configured to divide a frequency of the second mixing signal by two to provide a second divided frequency signal according to a second divider control signal corresponding to the selected one of the plurality of radio interfaces;
a second mixer coupled to the second low-pass filter and configured to mix signals from the second low-pass filter and the second frequency divider to produce a carrier-frequency transmission signal, wherein the second mixer has a signal path common to the plurality of radio interfaces and wherein the second mixer produces the carrier-frequency transmission signal on the basis of two 90-degree phase-shifted components produced from the second frequency divider;
a second gain-controlled amplifier coupled to the second mixer and configured to control gain according to a second gain control signal corresponding to the selected one of the plurality of radio interfaces, wherein the second gain-controlled amplifier has a signal path common to the plurality of radio interfaces;
a power amplifier coupled to the second gain-controlled amplifier and configured to produce an amplified output using a frequency band determined on the basis of a power control signal corresponding to the selected one of the plurality of radio interfaces, wherein the power amplifier has a signal path common to the plurality of radio interfaces;
a second controllable bandpass filter configured to filter an output of the power amplifier according to a second bandpass control signal that selects one of a second plurality of passbands corresponding to the selected one of the plurality of radio interfaces, wherein the second controllable bandpass filter has a signal path common to the plurality of radio interfaces; and
a microprocessor configured to generate one or more control signals to cause selection of the selected one of the plurality of radio interfaces, wherein at least one of the plurality of radio interfaces comprises a modulation, a channel spacing, and a channel bit rate that at least one other of the plurality of radio interfaces does not have.

2. A direct-conversion transmitter comprising:
a transmit synthesizer common to a plurality of radio interfaces of the direct-conversion transmitter and configured to generate a mixing signal;
a controllable low-pass filter common to the plurality of radio interfaces of the direct-conversion transmitter, the controllable low-pass filter configured to perform filtering of an analog baseband transmission signal using a controllable cut-off frequency according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected;
a frequency divider common to the plurality of radio interfaces of the direct-conversion transmitter, the frequency divider configured to divide a frequency of the mixing signal according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected, wherein the dividing produces two mixing signal components having a 90-degree phase difference; and
a controllable gain transmitter amplifier common to the plurality of radio interfaces of the direct-conversion transmitter and configured to amplify a carrier-frequency signal from a mixer at a gain controlled according to which one of the plurality of radio interfaces of the direct-conversion transmitter is selected, wherein at least one of the plurality of radio interfaces of the direct-conversion transmitter comprises a modulation, a channel spacing, and a channel bit rate that at least one other of the plurality of radio interfaces of the direct-conversion transmitter does not have.

3. The direct-conversion transmitter of claim 2 , wherein the frequency divider is configured to divide the frequency of the mixing signal so as to correspond to a selected transmission frequency band of a radio interface of the plurality of radio interfaces.

4. The direct-conversion transmitter of claim 3 , wherein a first radio interface of the plurality of radio interfaces employs a WCDMA system and a second radio interface of the plurality of radio interfaces employs a Global System for Mobile communications (GSM) system.

5. The direct-conversion transmitter of clai

Assignees

• Nokia Technologies Oy

Inventors

• VäISäNEN RISTO
• Kaltiokallio Kim

Classifications

• H04B1/0078

  with a common intermediate frequency amplifier for the different intermediate frequencies, e.g. when using switched intermediate frequency filters · CPC title

• H04W88/06

  adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals · CPC title

• H04B1/406

  with more than one transmission mode, e.g. analog and digital modes · CPC title

• H04B1/30

  for homodyne or synchrodyne receivers (demodulator circuits H03D1/22) · CPC title

• H04B1/0082

  with a common local oscillator for more than one band · CPC title