Data communication systems and methods

• US 8,908,573 B1
• Filed: 01/30/2014
• Issued: 12/09/2014
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Original Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Inventors: Wang, Tao, You, Zhongqian
• Primary Examiner(s): Liu, Jung-Jen
• Application Number:
  US14/169,011
• Time in Patent Office: 313 Days
• Field of Search: 370/203, 370204-215, 370229-240, 370310-337, 370338-350, 370351-394, 370/395.1, 370/395.3, 370/395.4, 370/395.41, 370/395.42, 370/395.5, 370/395.52, 370431-457, 370458-463, 370464-497, 370498-522, 370523-520, 370521-529
• US Class Current: 370/280
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04B 7/265 for channel frequency control
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/20 using signal quality detector
• 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 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04L 5/22 using time-division multiplexing
• CPC Class Codes: H04L 5/26 combined with the use of different frequencies
• CPC Class Codes: H04L 7/0033 Correction by delay
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 92/18 : between terminal devices

Abstract

The present invention provides systems and methods for improved data communication between communication terminals such as a base station and an unmanned aerial vehicle. In some instances, the systems and methods described herein provide robust transmission uplink data such as control data and wideband transmission of downlink data such as image data or other sensor data, while avoiding interference between the uplink data transmission and the downlink transmission.

Claims

1. A method for wireless communication between a remote controller and an unmanned aerial vehicle (UAV) using a plurality of cyclically repeating time division multiplexing (TDM) frames, each comprising a plurality of subframes, the method comprising:

(a) transferring, at a first data bandwidth, uplink data from the remote controller to the UAV while using a first subset of the plurality of subframes, the uplink data (1) encoded using a first coding scheme and (2) including control data for controlling flight of the UAV;

(b) transferring, at a second data bandwidth that is different than the first data bandwidth, downlink data from the UAV to the remote controller while using a second subset of the plurality of subframes, the downlink data encoded using a second coding scheme, the second coding scheme being different than the first coding scheme;

(c) prior to performing (a) or (b), selecting a working frequency channel from a plurality of frequency channels by measuring one or more quality characteristics associated with each of the plurality of frequency channels; and

(d) prior to or concurrent with performing (a) or (b), synchronizing the remote controller and the UAV by transmitting timing information relating to the transfer of the uplink data or the transfer of the downlink data between the controller and the UAV.

2. The method of claim 1, wherein the downlink data includes image data acquired by a visual sensor associated with the UAV.

3. The method of claim 1, wherein the second coding scheme is more efficient than the first coding scheme.

4. The method of claim 3, wherein the second coding scheme includes Low Density Parity Check Code (LDPC).

5. The method of claim 1, further comprising, in response to determining that transfer of the downlink data is not successful, re-transferring the downlink data from the UAV to the remote controller.

6. The method of claim 1, further comprising, in response to determining that transfer of the uplink data is not successful, allowing only the transfer of the uplink data.

7. The method of claim 1, further comprising dynamically changing the first coding scheme or the second coding scheme based at least in part on one or more channel conditions.

8. The method of claim 1, wherein the downlink data is transferred using the selected working frequency channel.

9. The method of claim 8, wherein the uplink data include synchronization information useful for synchronizing the remote controller and the UAV.

10. The method of claim 8, wherein the one or more quality characteristics include at least one of noise, interference, signal-to-noise ratio (SNR), bit error rate, or fading rate.

19. The method of claim 1, further comprising re-establishing the wireless communication between the remote controller and the UAV when the uplink data from the remote controller is not successfully received by the UAV.

21. The method of claim 1, wherein the number of subframes in the second subset is greater than the number of subframes in the first subset.

23. The method of claim 1, wherein the uplink data is transferred using a first frequency channel with a first channel bandwidth and the downlink data is transferred using a second frequency channel with a second channel bandwidth that is wider than the first bandwidth.

11. A method for wireless communication between a remote controller and a UAV using a plurality of cyclically repeating time division multiplexing (TDM) frames, each comprising a plurality of subframes, the method comprising:

(a) transferring, at a first data bandwidth, uplink data from the remote controller to the UAV while using a first subset of the plurality of subframes, the uplink data (1) modulated using a first modulation scheme and (2) including control data for controlling flight of the UAV; and

(b) transferring, at a second data bandwidth that is different than the first data bandwidth, downlink data from the UAV to the remote controller while using a second subset of the plurality of subframes, the downlink data modulated using a second modulation scheme, the second modulation scheme being different than the first modulation scheme;

(c) prior to performing (a) or (b), selecting a working frequency channel from a plurality of frequency channels by measuring one or more quality characteristics associated with each of the plurality of frequency channels; and

(d) prior to or concurrent with performing (a) or (b), synchronizing the remote controller and the UAV by transmitting timing information relating to the transfer of the uplink data or the transfer of the downlink data between the controller and the UAV.

12. The method of claim 11, wherein the uplink data comprising synchronization information useful for synchronizing operations of the remote controller and the UAV.

13. The method of claim 11, wherein the first modulation scheme includes at least one of Direct Sequence Spread Spectrum (DSSS), Frequency Hopping Spread Spectrum (FHSS), or Frequency Shift Keying (FSK).

14. The method of claim 11, wherein the second modulation scheme includes Quadrature Amplitude Modulation (QAM).

15. The method of claim 11, wherein the second modulation scheme is higher-order than the first modulation scheme.

16. The method of claim 11, further comprising dynamically changing the first modulation scheme or the second modulation scheme based at least in part on one or more channel conditions.

20. The method of claim 11, further comprising re-establishing the wireless communication between the remote controller and the UAV when the uplink data from the remote controller is not successfully received by the UAV.

22. The method of claim 11, wherein the number of subframes in the second subset is greater than the number of subframes in the first subset.

24. The method of claim 11, wherein the uplink data is transferred using a first frequency channel with a first channel bandwidth and the downlink data is transferred using a second frequency channel with a second channel bandwidth that is wider than the first bandwidth.

17. A data communication system, comprising:

a remote controller comprising a uplink transmitter and a downlink receiver; and

a UAV comprising an uplink receiver and a downlink transmitter, wherein;

the uplink transmitter is configured to transmit uplink data to the UAV in a first time slot;

the downlink receiver is configured to measure, in a second time slot, channel quality associated with one or more channels to select a working frequency channel and to receive, using the working frequency channel, downlink data provided by the second terminal in a third time slot;

the uplink receiver is configured to receive the uplink data in the first time slot; and

the downlink transmitter is configured to transmit, using the working frequency channel, the downlink data in the third time slot,

wherein a working frequency channel is selected from a plurality of frequency channels by measuring one or more quality characteristics associated with each of the plurality of frequency channels, and

wherein the remote controller and the UAV are synchronized by transmitting timing information relating to the transfer of the uplink data or the transfer of the downlink data between the controller and the UAV.

18. The system of claim 17, wherein the first time slot, the second time slot and the third time slot each includes one or more time division multiplexing (TDM) subframes.