Method and system for long-range adaptive mobile beam-forming ad-hoc communication system with integrated positioning

• US 9,516,513 B2
• Filed: 05/16/2012
• Issued: 12/06/2016
• Est. Priority Date: 05/16/2011
• Status: Active Grant

• Current Assignee: Radionor Communications AS
• Original Assignee: Radionor Communications AS
• Inventors: Sgrov, Atle, Kamben, Roger
• Primary Examiner(s): Khirodhar, Maharishi
• Application Number:
  US14/116,827
• Publication Number:
  US 20140105054A1
• Time in Patent Office: 1,665 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Method and system for provided a long range, high capacity ad-hoc mobile communication network where a narrow antenna beam formed by a plurality of antenna elements, radio transceivers and digital spatial signal processing is used to provide a high accuracy positioning system integrated into the communication system. The relative positions and directive orientation of all the units in the network is done by mutual exchange of positioning data as an element in the communication protocol in the network.

Claims

1. A method of setting up a wireless long range communication network between several communication units each having a Long-range Adaptive Mobile Beam-forming Ad-hoc Communication (LAMBACOM) unit (11) including an array Radio Frequency (RF) transceiver section (15), a spatial phase front analysis section (16), a delay section (18), a beam-former section (17), a RF switching section (13), an antenna element section (12), a positioning system (32), a communication controller (22) and a data link (23), comprising the following steps:

a. performing a frame-by-frame spatial scan for a phase modulated, coherent code-word from other communication units using spatial analysis of signals from the RF-transceiver section (15) through signal processing based on signals received and without requiring prior location of a source of said signals received;

b. provide beam forming according to a selection of optimum signal to interference ratio via utilizing a digital antenna beam-former (17) with an appropriate coefficient set to optimize signal energy before first received (RX) data are passed through a plurality of delay elements (18a-n) of the delay section (18) for achieving an optimum antenna shape and demodulation of the first received RX data from any direction;

c. calculating spatial angular direction of each received communication message from another communication unit in the wireless long range communication network;

d. measuring time-of-arrival between the communication units based on correlation of a code-word that is included in each communication message in the wireless long range communication network;

e. transmitting a response message to other communication units containing information about time-of-arrival for a decoded message and delay time from the time-of-arrival to the transmission of the response message; and

f. mutually exchanging position information between all communication units in the wireless long range communication network through the same RF transceiver section (15) that is used for positioning.

2. The method according to claim 1, comprising the step of using a local database with defined areas where transmission restrictions apply to define transmission power limits and frequencies in a sector of transmission.

3. The method according to claim 2, comprising the step of using a digital antenna beam-former for controlling the RF-transceiver section (15) so that emitted power level or frequencies or both around the communication unit are within the transmission restrictions.

4. The method according to claim 1, comprising the step of using positioning angle information from a LAMBACOM unit (11) or combined angle and distance measurements from several LAMBACOM units (11) for updating the position data of a predetermined LAMBACOM unit relative to other LAMBACOM units (11) for navigating mobile units in scenarios where all other navigation systems are unavailable.

5. The method according to claim 1, comprising the step of using information from the positioning system (32) for optimizing range of a communication link.

6. The method according to claim 1, comprising the step of using information from the positioning system (32) to reduce interference to or from other communication units.

7. The method according to claim 1, wherein step (c) includes focusing transmission energy in a sector around an estimated incoming signal when data shall be transmitted back to the other communication unit and updating internal lists of communication unit IDs and incoming directions, and updating distances for each received data frame.

8. The method according to claim 7, comprising the step of using an optimum combination of phases for a received signal to achieve the best signal-to-interference ratio, and using the ratio coefficients to calculate an estimate of the direction of origin of phase front and thereafter creating a phase coefficient set that provides one or several phase front directions where data is sent to the particular communication unit.

9. The method according to claim 1, wherein step (b) includes using a phase coherent modulated code-word as a start for each data frame, the code-word indicating the start of each data frame and being used for exact time and phase synchronization.

10. The method according to claim 9, characterized in that step (b) includes using a phase modulated code-word using a coherent and synchronously rotating code-book with complex modulated phase coded chips.

11. The method according to claim 1, comprising the step of using a tracking feedback/feed-forward method including using modulation data to analyze changes of dispersion, multipath, phase and time-of-arrival through decoding of a long frame for performing propagation channel training constantly without introducing additional link overhead.

12. The method according to claim 1, comprising the step of negotiating between the communication units in the wireless long range communication network for selecting a common time reference and electing a network coordinator that defines a time-slot services in the wireless long range communication network.

13. The method according to claim 12, comprising the step of determining ranges between the communication units, and arranging data transmissions in time slots with a given set of optimum link parameters.

14. The method according to claim 1, comprising the step of using a dedicated calibration network where all physical lengths from a reference transmitter to all antenna elements are equal for eliminating thermal skew in the wireless long range communication network.

15. The method according to claim 1, comprising the step of arranging several LAMBACOM units (11) at the same communication unit for covering of a larger sector and allowing fast handover in an ad-hoc network structure.

16. A system for setting up a wireless long range communication network between several communication units, comprising:

a Long-range Adaptive Mobile Beam-forming Ad-hoc Communication (LAMBACOM) unit (11) including an array Radio Frequency (RF) transceiver section (15), a spatial phase front analysis section (16), a delay section (18), a beam-former section (17), a RF switch section (13), an antenna element section (12) including a plurality of antenna elements (12a-n), a positioning system (32), a communication controller (22) and a data link (23), arranged to the communication units, characterized in that;

the communication controller (22) is configured for

frame-by-frame spatial analysis of signals from the RF-transceiver section (15) for determining time-of-flight between respective communication units and the direction of a communication unit relative to other communication units through signal processing based on signals received and without requiring prior location of a source of said signals received,

providing beam-forming according to a selection of optimum signal-to-interference ratio by providing a digital antenna beam-former (17) with an appropriate coefficient set to optimize signal energy before first RX data are passed through a plurality of delay elements (18a-n) of the delay section (18) for achieving an optimum antenna shape and demodulation of the first received RX data from any direction, and

using angular beam-forming information to provide a low latency positioning information for navigation purposes.

17. The system according to claim 16, comprising a database (31) containing information of transmission restrictions for local transmission power limits and frequencies for defined geographic areas.

18. The system according to claim 16, wherein the antenna elements (12a-n) are spread over a physical area, and that each antenna element (12a-n) is phase coherent with the other antenna elements (12a-n).

19. The system according to claim 16, wherein the RF-transceiver section (12) includes at least four adaptive antenna elements (12a-n).

20. The system according to claim 16, comprising a modulator/demodulator unit (20) arranged for constant envelope modulation with no amplitude components.

21. The system according to claim 16, wherein the digital antenna beam-former (17) is configured for controlling the antenna elements (12a-n) so that emitted power level or frequencies or both in defined areas around the communication unit are within the transmission restrictions.

22. The system according to claim 16, comprising a plurality of LAMBACOM units (11) arranged to each communication unit, wherein the system is configured for utilizing positioning information as a guiding system for movable communication units, for positioning each communication unit relative to other communication units in real time.

23. The system according to claim 16, configured for using positioning information from the positioning system (32) to perform one or more of:

i. optimizing range of a communication link;

ii. reducing interference to or from other communication units, and

iii. providing a tracking system for a mobile communication unit with a high frequency of position updates.

24. The system according to claim 16, comprising one or more additional sensors selected from the group consisting of an accelerometer (27), gyroscope (29), magnetometer (28), altitude determining unit (30) and Geographical Positioning sensors (26), for increasing positioning accuracy and increasing redundancy of the system.

25. The system according to claim 16, configured for providing a local time reference for use by the communication controller (22) to generate a common high precision clock reference signal and lock all F transceivers (15a-n) to this time reference.

26. The system according to claim 16, comprising a time-domain correlator (802) and a coherent local oscillator (905), the correlator (802) being arranged for determining the start of a data frame by correlating a pre-defined long code-word and determining the exact time-of-arrival and phase of the coherent local oscillator (905).

27. The system according to claim 16, comprising at least one adaptive filter (804) for increasing the signal-to-noise-ratio and reducing interference to or from other communication units and inter-symbol interference.

28. The system according to claim 16, comprising a dedicated calibration network (14) integrated into a printed circuit board where all physical lengths from a reference transmitter (910) to all antenna elements (12a-n) are substantially equal, thereby eliminating thermal skew in the wireless long range communication network.

29. A method of setting up a wireless long range communication network between several communication units each having a Long-range Adaptive Mobile Beam-forming Ad-hoc Communication (LAMBACOM) unit (11) including an array Radio Frequency (RF) transceiver section (15), a spatial phase front analysis section (16), a delay section (18), a beam-former section (17), a RF switching section (13), an antenna element section (12), a positioning system (32), a communication controller (22) and a data link (23), comprising the following steps:

a. performing a frame-by-frame spatial scan for a phase modulated, coherent code-word from other communication units using spatial analysis of signals from the RF-transceiver section (15) through signal processing based on signals received and without requiring prior location of a source of said signals received;

b. determining an optimum direction from the code-word before settings are applied to a complete decoding of a frame and updating beam forming for each received code-word;

c. calculating spatial angular direction of each received communication message from another communication unit in the wireless long range communication network;

d. measuring time-of-arrival between the communication units based on correlation of a code-word that is included in each communication message in the wireless long range communication network;

e. transmitting a response message to other communication units containing information about time-of-arrival for a decoded message and delay time from the time-of-arrival to the transmission of the response message; and

f. mutually exchanging position information between all communication units in the wireless long range communication network through the same RF transceiver section (15) that is used for positioning.