Doppler-nulling traveling-wave antenna relays for high-speed vehicular communications

• US 9,294,159 B2
• Filed: 12/16/2014
• Issued: 03/22/2016
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Original Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Inventors: Duerksen, Gary L.
• Primary Examiner(s): Wendell, Andrew
• Application Number:
  US14/572,733
• Publication Number:
  US 20150099459A1
• Time in Patent Office: 462 Days
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/32 Adaptation for use in or on road or rail vehicles
• CPC Class Codes: H01Q 13/203 Leaky coaxial lines
• CPC Class Codes: H04B 7/01 Reducing phase shift
• CPC Class Codes: H04W 84/005 Moving wireless networks

Abstract

An antenna relay system for facilitating wireless communication between mobile terminals on a high-speed rail vehicle and stationary base stations with substantially reduced Doppler shift effects comprises matched traveling wave directional antennas mounted to a high-speed rail vehicle and positioned collinearly alongside the railway. Both antennas continually transmit and receive at a fixed angle relative to the motion of the train so as to circumvent the Doppler shift. The signal transmitted or received by the stationary antenna is conducted to a nearest node for communication with an access network.

Claims

1. A system to enhance wireless communications in high-speed vehicles through Doppler-nulling traveling-wave antenna relays, the system comprising;

an access terminal on a vehicle adapted to transmit wireless communication signals to and receive wireless communication signals from a wireless communication network through a pair of leaky traveling-wave antennas; and

the pair of leaky traveling-wave antennas arranged to radiate substantially perpendicularly to a direction of motion of the vehicle, wherein

a first of the leaky traveling-wave antennas is positioned on the vehicle;

a second of the leaky traveling-wave antennas is positioned along a path of the vehicle and is conductively coupled to one or more access nodes of the wireless communication network; and

a Doppler frequency shift on the transmitted communication signals and the received communication signals resulting from a motion of the first leaky traveling-wave antenna relative to the second leaky traveling-wave antenna is minimized to zero due to the substantially perpendicular radiation of the pair of leaky traveling wave antennas relative to the direction of motion of the vehicle.

2. The system of claim 1, wherein the second leaky traveling-wave antenna conducts the transmitted communication signals and the received communication signals to a nearest access node of the wireless communication network.

3. The system of claim 2, wherein the transmitted communication signals are conducted to an access node behind the vehicle.

4. The system of claim 2, wherein the received communication signals are conducted to an access node in front of the vehicle.

5. The system of claim 1, wherein a first array of radiating elements of the first and second leaky traveling-wave antennas are positioned at a periodic predefined distance such that a guided wave mode of the first and second leaky traveling-wave antennas couples into a single radiation mode.

6. The system of claim 5, wherein a second array of radiating elements are interleaved along the first and second leaky traveling-wave antennas offset by about a quarter of the periodic predefined distance from the first array of radiating elements such that a stop band in the guided wave mode at wavelengths that couple into a broadside radiation mode is eliminated.

7. A vehicle capable of communication with a terrestrial network through Doppler-nulling traveling-wave antenna relays, the vehicle comprising:

an access terminal; and

a first leaky traveling-wave antenna adapted to transmit wireless communication signals from the access terminal to the terrestrial network through a second leaky traveling-wave antenna, wherein

the second leaky traveling-wave antenna is positioned along a path of the vehicle and is conductively coupled to one or more access nodes of the terrestrial network; and

the first and second leaky traveling-wave antennas are arranged to radiate substantially petpendicularly to a direction of motion of the vehicle such that a Doppler frequency shift on the transmitted communication signals resulting from a motion of the first leaky traveling-wave antenna relative to the second leaky traveling-wave antenna is minimized to zero.

8. The vehicle of claim 7, wherein the first leaky traveling-wave antenna is further adapted to provide the access terminal with wireless communication signals received from the terrestrial network through the second leaky traveling-wave antenna.

9. The vehicle of claim 7, wherein the first leaky traveling-wave antenna is suitably designed to radiate continuously along its length in highly directional beams.

10. The vehicle of claim 7, wherein the first leaky traveling-wave antenna is further adapted to transmit the wireless communication signals at a predefined angle.

11. The vehicle of claim 10, wherein the predefined angle deviates from 90 degrees between about 5 degrees and about 10 degrees.

12. The vehicle of claim 7, wherein a length of the first leaky traveling-wave antenna is substantially equal to a length of the vehicle.

13. the vehicle of claim 7, wherein the first leaky traveling-wave antenna is one of a leaky coaxial cable antenna, a slot array antenna, a directional dipole array antenna, and a patch array antenna.

14. A traveling-wave antenna system to enable wireless communication between high-speed vehicles and a terrestrial network, the system comprising:

a moving, antenna affixed to a vehicle and adapted to transmit wireless communication signals from an access terminal on the vehicle to the terrestrial network through a stationary antenna; and

the stationary antenna positioned, along, a path of the vehicle and conductively coupled to one or more access nodes of the terrestrial network, wherein the moving antenna and the stationary antenna are arranged to radiate substantially perpendicularly to a direction of motion of the vehicle such that a Doppler frequency shift on the transmitted communication signals resulting from a motion of the moving antenna relative to the stationary antenna is minimized to zero.

15. The antenna system of claim 14, wherein the moving antenna and the stationary antenna are leaky coaxial cables.

16. The antenna system of claim 15, wherein a first array of radiating elements in an outer conductor sheath of the leaky coaxial cables are positioned at a periodic predefined distance such that a guided wave mode of the leaky coaxial cables couples into a single radiation mode.

17. The antenna system of claim 16, wherein a radiation angle of the single radiation mode is given by θ

<sub>−

1</sub>=sin<sup>−

1</sup>(√

{square root over (ε

)}−

λ

/P), wherein ε

is a dielectric constant of a spacer material between the first array of radiating elements, λ

is a free space wavelength of a radiated wave from the leaky coaxial cables, and P is the periodic predefined distance between the first array of radiating elements of the leaky coaxial cables.

18. The antenna system of claim 16, wherein a second array of radiating, elements in the outer conductor sheath of the leaky coaxial cables are positioned along each leaky coaxial cable offset by about a quarter of the periodic predefined distance from the first array of radiating elements such that a stop band in the guided wave mode at wavelengths that couple into a broadside radiation mode is eliminated.

19. The antenna system of claim 14, wherein the moving antenna is further adapted to provide the access terminal with wireless communication signals received from the terrestrial network through the stationary antenna.

20. The antenna system of claim 19, wherein the stationary antenna is adapted to conduct the transmitted communication signals and the received wireless communication signals to a nearest access node of the terrestrial network.