US 5,537,435 AGranted

Transceiver apparatus employing wideband FFT channelizer with output sample timing adjustment and inverse FFT combiner for multichannel communication network

OwnerRonald Carney, Terry Williamsinventors

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Abstract

A physically compact, multichannel wireless communication transceiver architecture employs overlap and add or polyphase signal processing functionality, for wideband signal processing, together with a sample rate. A receiver section receives a plurality of multiple frequency communication channels and outputs digital signals representative of the contents of the plurality of multiple frequency communication channels. The receiver section contains an FFT-based channelizer that processes the digital signals output by a wideband digital receiver and couples respective channel outputs to a first plurality of digital signal processor units, which process (e.g. demodulate) respective ones of the digital channel signals and supply processed ones of the digital channel signals at respective output ports for distribution to an attendant voice/data network. On the transmit side, a transmit section contains a plurality of digital signal processors, respectively associated with respective ones of a plurality of incoming (voice/data) communication signals to be transmitted over respectively different frequency channels. Their processed (modulated, encoded) outputs are supplied to an inverse FFT combiner. The FFT combiner supplies a combined multichannel signal to a wideband transmitter which transmits a multiple frequency communication channel signal. Each of the channelizer and combiner may be implemented using overlap and add or polyphase filtering.

Claims67

Dependent claims

A transceiver apparatus for a wireless communication network containing multiple frequency communication channels for supporting communications among a plurality of geographically distributed first sites, by way of one or more transceiver sites, said transceiver apparatus being installable at a respective one of said one or more transceiver sites and comprising:

a receiver unit which is operative to receive a plurality of signals from a set of said multiple frequency communication channels and output a digital composite receiver signal representative of the signals received from said set of multiple frequency communication channels;
a Fourier transform based channelizer unit which is coupled to receive the digital composite receiver signal from said receiver unit and is operative to output respective digital channel signals representative of the contents of respective ones of the signals received from the plurality of communication channels received by said receiver unit;
a plurality of rate conversion units, respectively associated with said digital channel signals output by said Fourier transform based channelizer unit and being operative to output interpolated digital channel signals representative of respective ones of said digital channel signals in interpolated form with a sample rate timing different from a sample rate timing of the digital channel signals;
a first plurality of signal processor units, respectively associated with said interpolated digital channel signals output by said rate conversion units and being operative to demodulate respective ones of said interpolated digital channel signals and to supply demodulated ones of said digital channel signals at respective output ports thereof;
a second plurality of signal processor units, respectively associated with respective ones of a plurality of incoming communication signals to be transmitted over respectively different communication channels of said network, and being operative to process respective ones of said plurality of incoming communication signals and to supply processed ones of said incoming channel signals at respective output ports thereof;
a Fourier transform-based combiner unit which is coupled to receive said processed ones of said communication signals processed by said second plurality of digital signal processor units and to output a digital combined transmit signal representative of the contents of the incoming communication signals processed by said second plurality of digital signal processor units;
and
a transmitter unit which is operative to transmit a multiple frequency communication channel signal in accordance with the digital combined transmit signal output by said Fourier transform-based combiner unit.

5 more elements

For use with a wireless communication network having multiple frequency communication channels for supporting communications among a plurality of geographically distributed first sites by way of one or more transceiver sites, a method of transmitting and receiving wideband communication signals at a respective one of said one or more transceiver sites and comprising the steps of:

(a) receiving signals from a plurality of said multiple frequency communication channels and generating a plurality of digital signals representative of the contents of said plurality of multiple frequency communication channels;
(b) Fourier transform based channelizer processing said plurality of digital signals generated in step (a) and producing therefrom respective digital channel signals representative of the contents of respective ones of the signals received from the communication channels in step (a);
(c) converting the sample rate of respective ones of said digital channel signals, to provide respective interpolated digital channel signals representative of respective ones of said digital channel signals in interpolated form at a sample rate timing different from a sample rate timing of the digital channel signals;
(d) processing respective ones of said interpolated digital channel signals;
(e) processing respective ones of a plurality of incoming digital communication signals to be transmitted over respectively different frequency channels of said network;
(f) Fourier transform-processing digital communication signals processed in step (d) and producing therefrom a combined signal representative of the contents of the digital communication channel signals processed in step (e);
and
(g) transmitting a multiple frequency communication channel signal in accordance with the combined signal produced in step (f).

5 more elements

A transceiver apparatus for a wireless communication network containing multiple frequency communication channels for supporting communications, among a plurality of geographically distributed first sites, by way of one or more transceiver sites, said transceiver apparatus being installable at a respective one of said one or more transceiver sites and comprising:

a receiver unit which is operative to receive a plurality of said multiple frequency communication channels and output a digital signal representative of the contents of said plurality of multiple frequency communication channels;
a Fourier transform based channelizer unit which is coupled to receive a digital signal from said receiver unit and is operative to output respective digital channel signals representative of the contents of respective ones of the communication channels received by said receiver unit;
a plurality of rate conversion units, respectively associated with the digital channel signals output by said channelizer unit and being operative to output interpolated digital channel signals representative of respective ones of said digital channel signals in interpolated form, at least one of said rate conversion units including a decimating low pass filter structure, which is connected to receive the respective one of the digital channel signals, and connected to output the interpolated digital channel signals, the decimating low pass filter structure providing one of a plurality, L, of possible filter responses, and in which said decimating low pass filter structure additionally comprises a filter response selection unit, the filter response selection unit connected to the decimating low pass filter structure, to provide a filter selection signal to the decimating low pass filter structure to determine which of the L filter responses is selected as an active filter response at a given time;
a first plurality of signal processor units, respectively associated with the interpolated digital channel signals output by said rate conversion units and being operative to demodulate respective ones of said interpolated digital channel signals and to supply demodulated ones of said digital channel signals at respective output ports thereof;
a second plurality of signal processor units, respectively associated with respective ones of a plurality of incoming communication signals to be transmitted over respectively different frequency channels of said network, and being operative to process respective ones of said plurality of incoming communication signals and to supply processed ones of said communication channel signals at respective output ports thereof;
a Fourier transform,based combiner unit which is coupled to receive communication channel signals processed by said second plurality of digital signal processor units and to output a combined signal representative of the contents of the communication channel signals processed by said second plurality of digital signal processor units;
and
a transmitter unit which is operative to transmit a multiple frequency communication channel signal in accordance with the combined signal output by said Fourier transform-based combiner unit.

5 more elements

Dependencies are inferred from the claim text.