SYSTEM AND METHOD FOR SPREADING AND DE-SPREADING A SIGNAL AT AN ANTENNA

• US 20100208771A1
• Filed: 03/17/2010
• Published: 08/19/2010
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Altamira Technologies Corporation
• Original Assignee: Invertix
• Inventors: Law, Daniel A., Uhl, Brecken H., Hurtado, Arthur D.
• Granted Patent: US 8,457,251 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/20 Modulator circuits; Transmitter circuits

Abstract

A system and method for spreading and de-spreading a signal at an antenna. A Direct Spatial Antenna Modulation (DSAM) system makes use of the spatial characteristics of a radiating antenna structure to directly alter a signal transmitted or received by the radiating structure. When used for transmitting data, a data stream maps a carrier to different spatial points of excitation in the antenna structure, where each chosen configuration has different radiating characteristics including phase, amplitude, and polarization, which can be used represent data symbols. A code spreading sequence is applied to switch the output of the DSAM antenna to spatial points in the antenna to spread an input signal. The code spreading sequence is applied to a receive antenna to de-spread a previously spread signal. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this Abstract.

Claims

1. A direct spatial antenna modulation (DSAM) system comprising:

a radiating structure comprising a plurality of spatial points of origination; and

a control system, wherein the control system is connected to the radiating structure via one or more input ports and is configured to respond to a pseudo-random noise (PN) coded sequence to direct the modulated carrier signal to one or more spatial points of origination selected from the plurality of spatial points of origination via the one or more input ports,

wherein the selection of the one or more spatial points of origination spreads the bandwidth of the modulated carrier signal at transmission.

2. The DSAM system of claim 1, wherein the PN coded sequence comprises PN coded symbols, and wherein a unique PN coded symbol is associated with a particular configuration of the control system, and wherein in response to the presence of the unique PN coded symbol, the control system directs the modulated carrier signal to the one or more spatial points of origination selected from the plurality of spatial points of origination to transmit the modulated carrier shifted according to the unique PN code symbol.

3. The DSAM system of claim 1, the PN coded sequence comprises PN coded symbols, wherein the control system comprises one or more switching devices and wherein the control system directs the modulated carrier signal to the one or more spatial points of origination selected from the plurality of spatial points of origination by controlling the state of the one or more switching devices in response to the presence of a unique PN coded symbol.

4. The DSAM system of claim 3, wherein the PN coded sequence comprises PN coded symbols, and wherein the control system further comprises one or more amplitude control devices, wherein the control system configures the one or more amplitude control devices to adjust the amplitude of the modulated carrier to each spatial point of origination individually in response to the presence of a unique PN coded symbol, and wherein the selection of the one or more spatial points of origination and the amplitude of the modulated carrier determines a transmission characteristic of the spread carrier signal according to the unique PN coded symbol.

5. The DSAM system of claim 4, wherein the transmission characteristic is selected from the group consisting of an instantaneous phase, an amplitude, and a polarization.

6. The DSAM system of claim 1, wherein the radiating structure is selected from the group consisting of a rectangular microstrip patch antenna, a circular disc microstrip patch antenna, a quadrifilar helix antenna, a waveguide horn antenna, a crossed dipole antenna, a quadri-filar helix antenna, and a dual-arm sinuous antenna.

7. A direct spatial antenna modulation (DSAM) system comprising:

an antenna structure comprising a plurality of spatial points of origination and configured to receive a signal from a transmitter, wherein the signal comprises an original signal that has been spread using a pseudo-random noise (PN) coded sequence; and

a control system, wherein the control system is connected to the radiating structure and is configured to respond to the PN coded sequence to connect an output port to one or more spatial points of origination selected from the plurality of spatial points of origination,

wherein the PN coded sequence at the control system is synchronized to the PN coded sequence used to transmit the signal; and

wherein the selection of the one or more spatial points of origination according to the synchronized PN coded sequence produces the original signal at the output port.

8. The DSAM system of claim 7, wherein the control system comprises one or more switching devices and wherein the control system directs the output port to the one or more spatial points of origination selected from the plurality of spatial points of origination by controlling the state of the plurality of the one or more switching devices in response to the PN coded sequence.

9. The DSAM system of claim 7, wherein the PN coded sequence comprises PN coded symbols, wherein the control system further comprises one or more attenuation control devices, wherein the control system configures the one or more attenuation control devices to adjust the amplitude of the received signal directed to each spatial point of origination individually in response to the presence of a unique PN coded symbol, and wherein the selection of the one or more spatial points of origination and the attenuation at the spatial points of origination enables de-spreading of the received spread signal according to the synchronized coded sequence.

10. The DSAM system of claim 7, wherein the radiating structure is selected from the group consisting of a rectangular microstrip patch antenna, a circular disc microstrip patch antenna, a quadrifilar helix antenna, a waveguide horn antenna, a crossed dipole antenna, a quadri-filar helix antenna, and a dual-arm sinuous antenna.