Carrier recovery system and method

1. A receiver comprising:

a processor; and

a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations, comprising:

receiving a signal comprising one or more frames, each frame comprising a synchronization-symbol-portion, a security-sequence-portion with both a known security-sequence and an unknown security-sequence, and a data-payload-portion;

inspecting a data-payload-portion of a frame with the unknown security-sequence to obtain data;

using the obtained data to determine a target pattern for a security-sequence-portion of a subsequent frame;

performing ranging on the subsequent frame using the known security-sequence of the frame; and

performing a carrier recovery process on the signal, wherein at least part of the known security-sequence is included in the carrier recovery process and the unknown security-sequence is excluded from the carrier recovery process.

2. The receiver of claim 1 , wherein the receiver is further configured to exclude the unknown security-sequence by pausing the carrier recovery process for a duration of the unknown security-sequence.

3. The receiver of claim 1 , wherein each frame comprises a plurality of synchronization-symbol-sub-portions that are interleaved with a plurality of security-sequence-sub-portions.

4. The receiver of claim 1 , wherein the receiver has a priori knowledge of the format of the frames in the signal and is configured to suspend carrier recovery in accordance with the frame format to exclude the unknown security-sequence from the carrier recovery process.

5. The receiver of claim 1 , wherein the carrier recovery process comprises carrier phase recovery.

6. The receiver of claim 5 , wherein the receiver is further configured to perform carrier recovery using a tracking loop.

7. The receiver of claim 6 , wherein the receiver is further configured to perform carrier recovery using a dynamic-bandwidth-controlled tracking loop.

8. The receiver of claim 7 , wherein the synchronization-symbol-portion precedes the security-sequence-portion in each frame, and the receiver is further configured to reduce the bandwidth of the tracking loop as tracking progresses through the synchronization-symbol-portion.

9. The receiver of claim 7 , wherein the data-payload-portion follows the security-sequence-portion in each frame, and the receiver is further configured to increase the bandwidth of the tracking loop following the security-sequence-portion.

10. The receiver of claim 1 , wherein the receiver is further configured to perform the carrier recovery process on the data-payload-portion of each frame.

11. The receiver of claim 1 , wherein a known security-sequence is a security sequence that is verifiable by the receiver by cross-correlating the security-sequence-portion with a target pattern, and the unknown security-sequence is a security sequence that is unverifiable by the receiver by cross-correlating the security-sequence-portion with a target pattern.

12. A system comprising:

at least one receiver device configured to:

receive a signal comprising one or more frames, each frame comprising a synchronization-symbol-portion, a security-sequence-portion with both a known security-sequence and an unknown security-sequence, and a data-payload-portion,

inspect a data-payload-portion of a frame with the unknown security-sequence to obtain data,

use the obtained data to determine a target pattern for a security-sequence-portion of a subsequent frame, perform ranging on the subsequent frame using the known security-sequence of the frame, and

perform a carrier recovery process on the signal, wherein at least part of the known security-sequence is included in the carrier recovery process and the unknown security-sequence is excluded from the carrier recovery process; and

at least one transmitter device configured to communicate with the at least one receiver device, generate a signal comprising one or more frames, each frame comprising a synchronization-symbol-portion, a security-sequence-portion with both a known security-sequence and an unknown security-sequence, and a data-payload-portion, wherein at least part of the known security-sequence is included in a carrier recovery process and the unknown security-sequence is excluded from the carrier recovery process.

13. The system of claim 12 , wherein each frame includes a plurality of synchronization-symbol-portions, one or more of the synchronization-symbol-portions are provided after the security-sequence-portion, and synchronization symbols are provided within the data-payload-portion.

14. The system of claim 12 , wherein the signal comprises a quadrature or higher order modulated symbol stream and the at least one transmitter device is configured to modulate the security-sequence-portion with the synchronization-symbol-portion or the data-payload-portion.

15. The system of claim 12 , wherein the at least one receiver device and the at least one transmitter device are Impulse Radio Ultra-WideBand (IR-UWB) devices.

16. The system of claim 12 , wherein the system comprises at least one of:

an access control system for a building;

a passive keyless entry and/or start system for an automobile;

a contactless payment terminal; and

an automatic teller machine.

17. A method for operating a receiver device, the method comprising:

receiving a signal comprising one or more frames, each frame comprising a synchronization-symbol-portion, a security-sequence-portion with both a known security-sequence and an unknown security-sequence, and a data-payload-portion;

inspecting a data-payload-portion of a frame with the unknown security-sequence to obtain data;

using the obtained data to determine a target pattern for a security-sequence-portion of a subsequent frame;

performing ranging on the subsequent frame using the known security-sequence of the frame; and

processing the signal to perform carrier recovery, wherein at least part of the known security-sequence is included in the carrier recovery process and the unknown security-sequence is excluded from the carrier recovery process.