Method and apparatus for synchronizing a radio telemetry system by way of transmitted-reference , delay-hopped ultra-wideband pilot signal

• US 20030198212A1
• Filed: 04/19/2002
• Published: 10/23/2003
• Est. Priority Date: 04/19/2002
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoctor, Ralph Thomas, Hladik, Stephen Michael
• Granted Patent: US 7,313,127 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/7183 Synchronisation

Abstract

A time-division-multiplexed radio communication system and method uses transmitted-reference, delay-hopped (TR/DH) ultra-wideband (UWB) broadcast signal to provide a pilot signal to all mobile devices in a coverage area from which time synchronization is derived. Using this TR/DH UWB pulse pilot signal and low-complexity demodulation in the mobile devices, the mobile devices utilize a simple signal detection algorithm to acquire synchronization with the pilot signal. As a result, all devices in a local area network become synchronized to the system'"'"'s bit clock. This greatly reduces the search space required for signal acquisition, receiver signal processing complexity, and length of message preambles required to synchronize the base station receiver to a transmission from any of the mobile devices.

Claims

1. A method for synchronizing a radio telemetry system using radio frequency (RF) burst communications comprising the steps of:

generating at a base station a transmitted-reference (TR) pilot signal transmission;

transmitting by the base station a transmitted-reference, delay-hopped (TR/DH) pilot signal to a plurality of mobile devices in the radio telemetry system;

using the TR/DH pilot signal and a TR/DH receiver and time-of-arrival estimator in each of the plurality of mobile devices to acquire synchronization with the base station;

generating and buffering telemetry data at each of the plurality of mobile devices; and

transmitting by each of the mobile devices telemetry data at a predetermined time after synchronization with the base station.

2. The method for synchronizing a radio telemetry system recited in claim 1, wherein the RF burst transmission is a burst of time modulated ultra-wideband (UWB) communications transmission.

3. The method for synchronizing a radio telemetry system recited in claim 1, wherein the TR/DH pilot signal comprises a code word consisting of N_c chips, transmitted sequentially, having a fixed duration, T_c, each chip being composed of N_p pulse pairs.

4. The method for synchronizing a radio telemetry system recited in claim 1, wherein the TR/DH pilot signal comprises two noise signals transmitted for a time period of duration T_c.

5. The method for synchronizing a radio telemetry system recited in claim 1, wherein the transmissions from the mobile devices to the base station are a narrowband modulation.

6. The method for synchronizing a radio telemetry system recited in claim 5, wherein the narrowband modulation is Gaussian Minimum Shift Keying (GMSK).

7. The method for synchronizing a radio telemetry system recited in claim 1, wherein the telemetry system uses a time division, multiple access (TDMA) scheme for transmitting telemetry data.

8. The method for synchronizing a radio telemetry system recited in claim 1, wherein the telemetry system uses a time slotted transmission scheme for transmitting telemetry data.

9. A radio telemetry system using radio frequency (RF) burst communications comprising a base station and a plurality of mobile devices, apparatus for synchronizing the radio telemetry system comprising:

a pilot signal generator at the base station for generating a transmitted-reference pilot signal, the base station broadcasting a transmitted-reference, delay-hopped (TR/DH) pilot signal to the mobile devices;

a TR/DH receiver and time-of-arrival estimator at each of the mobile devices for detecting the TR/DH pilot signal to acquire synchronization with the transmitter;

a data buffer for temporarily storing telemetry data at each of the mobile devices; and

a transmitter at each of the mobile devices for transmitting buffered telemetry data at a predetermined time after synchronization with the base station.

10. A radio telemetry system as recited in claim 9, wherein the RF burst transmission is a burst of time modulated ultra-wideband (UWB) burst transmission.

11. A radio telemetry system as recited in claim 9, wherein the TR/DH pilot signal comprises a code word consisting of N_c chips, transmitted sequentially, having a fixed duration, T_c, each chip being composed of N_p pulse pairs.

12. A radio telemetry system as recited in claim 9, wherein the TR/DH pilot signal comprises two noise signals transmitted for a time period of duration T_c.

13. A radio telemetry system as recited in claim 9, wherein the transmissions from the mobile devices to the base station are a narrowband modulation.

14. A radio telemetry system as recited in claim 13, wherein the narrowband modulation is Gaussian Minimum Shift Keying (GMSK).

15. A radio telemetry system as recited in claim 9, wherein the telemetry system uses a time division, multiple access (TDMA) scheme for transmitting telemetry data.

16. A radio telemetry system as recited in claim 9, wherein the telemetry system uses a time slotted transmission scheme for transmitting telemetry data.

17. A radio telemetry system as recited in claim 9, wherein the TR/DH pilot signal comprises a code word consisting of N_c chips, transmitted sequentially, having a fixed duration, T_c, each chip being composed of N_p pulse pairs, the TR/DH receiver further comprising:

a bank of pulse pair correlators receiving the TR/DH pilot signal and generating outputs;

a bank of analog-to-digital converters (ADCs) digitizing the outputs of the bank of pulse pair correlators;

a DH code word correlator receiving the digitized outputs from the bank of ADCs and generating a correlation output; and

time estimation logic receiving the correlation output of the DH code word correlator and generating timing information for generating a numerical time-of-arrival (TOA) estimate.

18. A telemetry system as recited in claim 17, wherein the DH code word correlator is implemented as an application specific integrated circuit (ASIC).

19. A telemetry system as recited in claim 17, wherein the DH code word correlator is implemented as a programmable logic device (PLD).

20. A telemetry system as recited in claim 17, wherein time estimation logic detects the TR/DH pilot signal by estimating a TOA of a burst of RF composed of a TR/DH code word using a model.

21. A radio telemetry system as recited in claim 17, wherein the time estimation logic is implemented using an application specific integrated circuit (ASIC).

22. A radio telemetry system as recited in claim 17, wherein the time estimation logic is implemented using programmable logic device (PLD).

23. A radio telemetry system as recited in claim 17, wherein the time estimation logic includes a programmable digital signal processor (DSP) to convert a numerical TOA estimate to a clock edge for controlling a start of transmission of telemetry data.

24. A mobile device for a radio telemetry system including apparatus for initial synchronization with a central transmitter comprising:

a receiver for detecting a transmitted-reference, delay-hopped (TR/DH) pilot signal to acquire synchronization with the central transmitter;

a buffer for temporarily storing telemetry data; and

a transmitter for transmitting buffered telemetry data at a predetermined time after synchronization with the central transmitter.

25. A mobile device for a radio telemetry system as recited in claim 24, wherein the TR/DH pilot signal comprises a code word consisting of N_c chips, transmitted sequentially, having a fixed duration, T_c, each chip being composed of N_p pulse pairs.

26. A mobile device for a radio telemetry system as recited in claim 24, wherein the TR/DH pilot signal comprises two noise signals transmitted for a time period of duration T_c.

27. A mobile device for a radio telemetry system as recited in claim 24, wherein the transmissions from the mobile devices to the base station are a narrowband modulation.

28. A mobile device for a radio telemetry system as recited in claim 27, wherein the narrowband modulation is Gaussian Minimum Shift Keying (GMSK).

29. A mobile device for a radio telemetry system as recited in claim 24, wherein transmission of buffered telemetry data is based on a time division, multiple access (TDMA) scheme.

30. A mobile device for radio telemetry system as recited in claim 24, wherein transmission of buffered telemetry data is based on a time slotted transmission txtv scheme.