Demodulation of multiple signals

• US 7,133,471 B2
• Filed: 12/05/2005
• Issued: 11/07/2006
• Est. Priority Date: 08/10/1998
• Status: Expired due to Fees

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Kamilo Feher
• Inventors: Feher, Kamilo
• Primary Examiner(s): TRAN, KHANH C
• Application Number:
  US11/294,656
• Publication Number:
  US 20060083320A1
• Time in Patent Office: 337 Days
• Field of Search: 375/130, 375/260, 375261-262, 375/271, 375/284, 375/285, 375/216, 375/324, 375/340, 375/341, 370/206, 370/210, 455/133
• US Class Current: 375/340
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/70707 Efficiency-related aspects
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04L 1/205 jitter monitoring
• CPC Class Codes: H04L 2025/03407 Continuous phase
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 25/03025 using a two-tap delay line
• CPC Class Codes: H04L 25/0305 using blind adaptation
• CPC Class Codes: H04L 25/0307 using blind adaptation
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 27/00 Modulated-carrier systems
• CPC Class Codes: H04L 27/0004 using wavelets
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/01 Equalisers baseband equalizers at the transmitter end H04L25/03343; in analogue transmission systems H04B3/04, H04B7/005
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/186 in which the information is carried by both the individual signal points and the subset to which the individual signal points belong, e.g. coset coding or related schemes
• CPC Class Codes: H04L 27/2017 in which the phase changes are non-linear, e.g. generalized and Gaussian minimum shift keying, tamed frequency modulation H04L27/201 takes precedence
• CPC Class Codes: H04L 27/2637 : with direct modulation of individual subcarriers
• CPC Class Codes: H04L 27/34 : Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04L 5/0008 : Wavelet-division
• CPC Class Codes: H04L 5/0016 : Time-frequency-code
• CPC Class Codes: H04L 5/0028 : Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 7/0008 : Synchronisation information channels, e.g. clock distribution lines

Abstract

A demodulation system for receiving and demodulating multiple modulated signals, including a first modulated signal having a first bit rate and/or a first modulation format and a second modulated signal having a second bit rate and/or a second modulation format.

The demodulator demodulating the first modulation format modulated signal provides a cross-correlated demodulated in-phase and quadrature-phase baseband signal and the demodulator demodulating the second modulation format modulated signal provides a second demodulated baseband signal. A selector selects either the first or the second or both bit rate and/or modulation format demodulated baseband signals. In an alternative embodiment two demodulators are implemented for the demodulation of multiple signals. In certain embodiments the demodulator demodulating the first bit rate modulated signal or the second bit rate modulated signal is comprised of bit rate switchable filters and/or mis-matched filters which are mismatched to that of the filters of the modulator of the first or the second bit rate modulated signal. In some of the applications the first or the second modulated signal is an Orthogonal Frequency Division Multiplexed (OFDM) modulated signal and/or a spread spectrum modulated signal and/or Phase Shift Keying (PSK) modulation, or a Quadrature Modulation (QM), or a Frequency Modulation (FM) modulated signal. In certain implementations and applications the demodulator is used for demodulation of Gaussian Minimum Shift Keying (GMSK) modulated signals and spread spectrum modulated signals.

Claims

1. A demodulation system comprising:

a network for receiving a first modulated signal having a first bit rate and a second modulated signal having a second bit rate;

a demodulator demodulating the first bit rate modulated signal providing cross-correlated demodulated in-phase and quadrature-phase baseband signals and demodulating the second bit rate modulated signal providing a demodulated baseband signal;

a selector for selecting either the first or the second or both bit rate demodulated baseband signals.

2. The demodulation system as in claim 1 wherein the demodulator demodulating the first bit rate modulated signal or the second bit rate modulated signal is comprised of bit rate switchable filters.

3. The demodulation system as in claim 1 wherein the demodulator demodulating the first bit rate modulated signal is comprised of mis-matched filters which are mismatched to the filters of the modulator of the first bit rate modulated signal.

4. The demodulation system as in claim 1 wherein the first or the second modulated signal is an Orthogonal Frequency Division Multiplexed (OFDM) modulated signal.

5. The demodulation system as in claim 1 wherein the first or the second modulated signal is a spread spectrum modulated signal.

6. The demodulation system as in claim 1 wherein the first modulated signal is a Gaussian Minimum Shift Keying (GMSK) modulated signal and the second modulated signal is a spread spectrum modulated signal.

7. The demodulation system as in claim 1 wherein the first or the second modulated signal is a Frequency Shift Keying (FSK) modulated signal.

8. A demodulation system comprising:

a network for receiving a first modulated signal having a first modulation format and a second modulated signal having a second modulation format;

a demodulator for demodulating the first modulated signal and the second modulated signal and for providing cross-correlated demodulated in-phase and quadrature phase baseband signals corresponding to the first modulated signal and for providing demodulated baseband signals corresponding to the second modulated signal;

a selector for selecting either the first or the second demodulated signals.

9. The demodulation system as in claim 8 wherein the demodulator demodulating the first modulated signal or the second modulated signal is comprised of bit rate switchable filters.

10. The demodulation system as in claim 8 wherein the demodulator demodulating the first modulation signal is comprised of mis-matched filters which are mismatched to the filters of the modulator of the first modulated signal.

11. The demodulation system as in claim 8 wherein the first or the second modulated signal is an Orthogonal Frequency Division Multiplexed (OFDM) modulated signal.

12. The demodulation system as in claim 8 wherein the first or the second modulated signal is a spread spectrum modulated signal.

13. The demodulation system as in claim 8 wherein the first or the second modulated signal is a Phase Shift Keying (PSK) modulation, or a Quadrature Modulation (QM), or a Frequency Modulation (FM) modulated signal.

14. A receiver and demodulation system comprising:

a network for receiving a first and a second modulated signal;

a first demodulator for demodulating the first modulated signal and for providing demodulated cross-correlated in-phase and quadrature-phase baseband signals;

a second demodulator for demodulating the second modulated signal and for providing a demodulated baseband signal;

a selector for selecting either the first or the second demodulated baseband signal.

15. The receiver and demodulation system as in claim 14 wherein the first demodulator is comprised of mis-matched filters which are mismatched to the filters of the modulator providing the first modulated signal.

16. The receiver and demodulation system as in claim 14 wherein the second modulated signal is an Orthogonal Frequency Division Multiplexed (OFDM) modulated signal.

17. The receiver and demodulation system as in claim 14 wherein the first or the second modulated signal is a spread spectrum modulated signal.

18. The receiver and demodulation system as in claim 14 wherein the first modulated signal is a Gaussian Minimum Shift Keying (GMSK) modulated signal and the second modulated signal is a spread spectrum modulated signal.

19. The receiver and demodulation system as in claim 14 wherein the first or the second modulated signal is a Frequency Shift Keying (FSK) modulated signal.

20. The receiver and demodulation system as in claim 14 wherein the first or the second modulated signal is a Phase Shift Keying (PSK) modulation, or a Quadrature Modulation (QM), or a Frequency Modulation (FM) modulated signal.