Wireless Frequency-Domain Multi-Channel Communications

• US 20100142598A1
• Filed: 09/25/2007
• Published: 06/10/2010
• Est. Priority Date: 12/05/2006
• Status: Active Grant

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Dyadyuk, Valeriy, Murray, Boyd McGregor, Pathikulangara, Joseph Abraham, Bunton, John, Abbott, David Andrew
• Granted Patent: US 8,379,698 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths
• CPC Class Codes: H04L 2027/0024 at the receiver end
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/2637 with direct modulation of individual subcarriers
• CPC Class Codes: H04L 27/2653 with direct demodulation of individual subcarriers
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

A circuit for transmission and reception of multi-channel communications is disclosed. The transmitter path includes a digital modulation circuit receiving multiple channel binary data, and for each channel generating a digital representation of the data. A digital-to-analogue (D/A) conversion circuit (140-146) is provided for each data channel. Each D/A conversion circuit receives and converts respective channel digital representations to produce a resultant band limited analogue signal (148-154). The band limitation arises due to a characteristic of said channel digital representations. A bandpass filter (156-162) receives and filters each analogue channel signal. The band width to the start of the stop band of each bandpass filter is wider than a respective band limited analogue channel signal and wider than the Nyquist bandwidth arising from the sampling rate of said D/A conversion circuit. In this way, signal power in unwanted Nyquist zones is effectively removed. A frequency translation circuit (172-188) abuts the multiple channel bandpass filtered analogue signals in the frequency domain without any guard bands between adjacent channel signals.

Claims

1. A circuit comprising:

a digital modulation circuit receiving multiple channel binary data, and for each channel generating a digital representation;

a digital-to-analogue (D/A) conversion circuit for each data channel, each said D/A conversion circuit receiving and converting respective said channel digital representations to produce a resultant analogue signal that is band limited within at least one Nyquist zone, said band limitation being dependent on a characteristic of said channel digital representations;

a bandpass filter receiving and filtering each analogue signal, the band width to the start of the stop band of each said bandpass filter being wider than a respective band limited analogue signal and wider than the Nyquist bandwidth arising from the sampling rate of said D/A conversion circuit, whereby signal power in unwanted Nyquist zones is effectively removed; and

a frequency translation circuit for abutting said multiple channel bandpass filtered analogue signals in the frequency domain without any guard bands between adjacent channel signals.

2. A circuit according to claim 1, wherein said digital modulation circuit converts one of more channel binary data values to a symbol value, and generates a summed time sequence of digital data values implementing constituent impulse responses for each said symbol value.

3. A circuit according to claim 1, wherein said characteristic of said digital representations is a symbol rate and a parameter α

.

4. A circuit according to claim 2, wherein said digital modulation circuit includes a memory storing said digital data values implementing said impulse responses that correspond to said symbol values.

5. A circuit according to claim 2, wherein said symbols are at least 3 bits in length.

6. A circuit according to claim 2, wherein said digital modulation circuit implements a Raised Root Cosine filter to generate said time sequences.

7. A circuit according to claim 1, wherein said digital modulation circuit implements any one of 8 value phase shift keying (8-PSK), or 16 or 64 value quadrature amplitude modulation.

8. A circuit according to claim 1, wherein said band limited analogue channel signal occupies no more than 40% of the total bandpass filter width as measured to the edge of the stop bands.

9. A circuit according to claim 1, further comprising a digital demultiplexer circuit, demultiplexing input binary data into said multiple channel binary data.

10. A circuit according to claim 1, wherein there are at least 4 said channels.

11. A circuit according to claim 1, further comprising a radio frequency circuit to combine said abutted channel signals and transmit said combine signals at radio frequencies.

12. A method for transmitting data comprising:

forming a limited duration digital representation of multiple input data channels;

converting each said digital representation to an analogue signal that is band limited within at least one Nyquist zone for each channel;

bandpass filtering each analogue signal for each channel, wherein the band width to the start of the stop band of each said bandpass filter being wider than a respective band limited analogue signal and wider than the Nyquist bandwidth arising from the sampling rate of said conversion, whereby signal power in unwanted Nyquist zones is effectively removed;

abutting said bandpass filtered analogue signals in the frequency domain without any guard bands; and

wirelessly transmitting said abutted bandpass filtered analogue signals.

13. A transceiver comprising:

(a) a transmitter circuit including;

a digital modulation circuit receiving multiple channel binary data, and for each channel generating a digital representation;

a digital-to-analogue (D/A) conversion circuit for each data channel, each said D/A conversion circuit receiving and converting respective said channel digital representations to produce a resultant analogue signal that is band limited within at least one Nyquist zone, said band limitation being dependent on a characteristic of said channel digital representations;

a bandpass filter receiving and filtering each analogue signal, the band width to the start of the stop band of each said bandpass filter being wider than a respective band limited analogue signal and wider than the Nyquist bandwidth arising from the sampling rate of said D/A conversion circuit, whereby signal power in unwanted Nyquist zones is effectively removed; and

a frequency translation circuit for abutting said multiple channel bandpass filtered analogue signals in the frequency domain without any guard bands between adjacent channel signals; and

(b) a receiver circuit including;

a radio frequency circuit to receive a multiple channel radio frequency signal, said multiple channels being abutted;

a frequency translation circuit for separating said received multiple channel signals by frequency translation;

an analogue-to-digital (A/D) conversion circuit for each channel, each said A/D conversion circuit converting a respective analogue channel signal to a digital representation; and

a digital demodulation circuit receiving said channel signal digital representation and generating channel symbols therefrom, and generating multiple channel binary data from said symbols.

14. A transceiver according to claim 13, wherein said receiver further includes a bandpass filter for each separate channel signal to filter said channel signals before passing the signals to the respective A/D conversion circuit.

15. A transceiver according to claim 13, wherein said demodulation circuit includes a filter component matching channel signals in the modulation circuit of the transmitter circuit.

16. A transceiver according to claim 13, wherein

said transmitter circuit further includes a digital demultiplexer, demultiplexing input binary data into said multiple channel binary data;

and

said receiver circuit further includes a digital multiplexer, multiplexing said binary channel data in to a single output data stream.

17. A transceiver according to claim 13, wherein said receiver circuit further includes a bandpass filter for each separate channel signal to filter said channel signals before passing the signals to the respective A/D conversion circuits.

18. A transceiver according to claim 13, wherein said digital demodulation circuit includes a filter component matching a filter component in the digital modulation circuit of the transmitter circuit.

19. A transmitter generating abutted multiple channel signals without any guard bands between adjacent channels.

20. A receiver for receiving and demodulating abutted multiple channel signals without any guard bands between adjacent channels to recover binary data.

21. A circuit comprising:

a digital modulation circuit receiving multiple channel binary data, and for each channel, converting one or more channel binary data values to a symbol value, and generating a summed time sequence of digital data values implementing constituent impulse responses at a predetermined centre frequency for each said symbol value;

a digital-to-analogue (D/A) conversion circuit for each data channel, each said D/A conversion circuit receiving and converting respective said channel time sequences to produce a resultant analogue signal at a predetermined sampling frequency, wherein said predetermined sampling frequency is 4/3 times said centre frequency;

a bandpass filter receiving and filtering each analogue signal, whereby signal power in unwanted Nyquist zones is effectively removed; and

a frequency translation circuit for abutting said multiple channel bandpass filtered analogue signals in the frequency domain without any guard bands between adjacent channel signals.