Systems and methods for determining and compensating for offsets in RF communications

• US 10,243,766 B2
• Filed: 08/22/2017
• Issued: 03/26/2019
• Est. Priority Date: 07/05/2017
• Status: Active Grant

• Current Assignee: Calamp Wireless Networks Inc. (CalAmp Corporation)
• Original Assignee: LoJack Corporation (Solera Holdings Incorporated)
• Inventors: Whelan, Yvonne
• Primary Examiner(s): Timory, Kabir A
• Application Number:
  US15/683,000
• Publication Number:
  US 20190013976A1
• Time in Patent Office: 581 Days
• CPC Class Codes: H04L 2027/0026 Correction of carrier offset
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/2014 in which the phase changes in a piecewise linear manner during each symbol period, e.g. minimum shift keying, fast frequency shift keying H04L27/201 takes precedence
• CPC Class Codes: H04L 27/2082 for offset or staggered quadrature phase shift keying
• CPC Class Codes: H04L 27/2659 Coarse or integer frequency offset determination and synchronisation

Abstract

Systems and methods for identifying and compensating for offsets in received transmission signals in accordance with embodiments of the invention are disclosed. In one embodiment, a vehicle telematics device includes a processor, a transceiver connected to the processor, and a memory connected to the processor and storing a signal detection application, wherein the signal detection application directs the processor to command the transceiver to acquire a transmitted signal based on a set of listening parameters, store the transmitted signal as received signal data, determine the presence of a signal offset by determining monotonicity in the received signal data, generate offset data based on the determined monotonicity, command the transceiver to adjust at least one listening parameter based on the offset data, demodulate the received signal data based on the adjusted listening parameters, and issue a low power command signal.

Claims

1. A vehicle telematics device, comprising:

a processor;

a transceiver connected to the processor; and

a memory connected to the processor and storing a signal detection application;

wherein the signal detection application directs the processor to;

command the transceiver to acquire a transmitted signal based on a set of listening parameters;

store the transmitted signal as received signal data;

determine a presence of a signal offset by determining monotonicity in the received signal data;

generate offset data based on the determined monotonicity;

command the transceiver to adjust at least one listening parameter based on the offset data;

demodulate the received signal data based on the adjusted listening parameters; and

issue a low power command signal.

2. The vehicle telematics device of claim 1, wherein the determination of a signal offset is based on a subset of the received signal data.

3. The vehicle telematics device of claim 1, wherein the signal detection application further directs the processor to examine received signal data for changes in sign in the received signal data values.

4. The vehicle telematics device of claim 1, wherein the transmitted signal is a modulated signal.

5. The vehicle telematics device of claim 4, wherein the modulated signal is modulated with minimum shift keying.

6. The vehicle telematics device of claim 1, wherein the at least one listening parameter is amplitude.

7. The vehicle telematics device of claim 1, wherein the at least one listening parameter is frequency.

8. The vehicle telematics device of claim 1, wherein the offset data represents the frequency of the transmitted offset.

9. The vehicle telematics device of claim 8, wherein the adjustment of the at least one listening parameter adds the offset data frequency to the listening parameter.

10. The vehicle telematics device of claim 1, wherein the signal detection application further directs the processor to:

Determine a presence of a stored modulated signal in the received signal data;

keep the transceiver in an active state until the modulated signal is stored in the received signal data;

wait for a specified time period before again determining the presence of a stored modulated signal in the received signal data; and

demodulate the stored modulated signal in the received signal data based on the adjusted listening parameters.

11. A method for determining and compensating for offsets in transmission signals, comprising:

acquiring a transmitted signal based on a set of listening parameters using a vehicle telematics device comprising a processor and a memory;

storing the transmitted signal in the received signal data using the vehicle telematics device;

determining a presence of a signal offset by determining monotonicity in the received signal data using the vehicle telematics device;

generating offset data based on the determined monotonicity using the vehicle telematics device;

directing the transceiver to adjust at least one listening parameter based on the offset data using the vehicle telematics device;

demodulating the received signal data based on the adjusted listening parameters using the vehicle telematics device; and

issuing a low power command signal using the vehicle telematics device.

12. The method of claim 11, wherein the determination of a signal offset is based on a subset of the received signal data.

13. The method of claim 11, further comprising examining received signal data for changes in sign in the received signal data values using the vehicle telematics device.

14. The method of claim 11, wherein the transmitted signal is a modulated signal.

15. The method of claim 11, wherein the modulated signal is modulated with minimum shift keying.

16. The method of claim 15, wherein the at least one listening parameter is amplitude.

17. The method of claim 11, wherein the at least one listening parameter is frequency.

18. The method of claim 11, wherein the offset data represents the frequency of the transmitted offset.

19. The method of claim 18, wherein the adjustment of the at least one listening parameter adds the offset data frequency to the listening parameter.

20. The method of claim 11, wherein the method further includes:

Determining a presence of a stored modulated signal in the received signal data using the vehicle telematics device;

keeping the transceiver in an active state until the modulated signal is stored in the received signal data using the vehicle telematics device;

waiting for a specified time period before again determining the presence of a stored modulated signal in the received signal data using the vehicle telematics device; and

demodulating the stored modulated signal in the received signal data based on the adjusted listening parameters using the vehicle telematics device.