Communications systems and methods

• US 20070025739A1
• Filed: 07/29/2005
• Published: 02/01/2007
• Est. Priority Date: 07/28/2005
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Artimi Inc. (Veebeam Corporation)
• Inventors: Moore, Mark Justin, Lang, Jack Arnold
• Granted Patent: US 7,580,643 B2
• Time in Patent Office: Days
• US Class Current: 398/202
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04B 10/66 Non-coherent receivers, e.g. using direct detection

Abstract

This invention relates to systems and methods for wireless and wired optical data communications, in particular infrared data communications using techniques borrowed ultra wideband (UWB) radio. An optical data communications receiver for receiving data encoded using optical pulse position, the receiver comprising: an optical signal reception device; a reference signal memory for storing a reference channel response signal; and a correlator coupled to said reference signal memory and to said optical signal reception device for correlating a received optical pulse with said stored reference channel response signal to determine said optical pulse position; an output coupled to said correlator to provide pulse position data for said received optical pulse.

Claims

1. An optical data communications receiver for receiving data encoded using optical pulse position, the receiver comprising:

an optical signal reception device;

a reference signal memory for storing a reference channel response signal; and

a correlator coupled to said reference signal memory and to said optical signal reception device for correlating a received optical pulse with said stored reference channel response signal to determine said optical pulse position; and

an output coupled to said correlator to provide pulse position data for said received optical pulse.

2. An optical data communications receiver as claimed in claim 1 further comprising a reference signal acquisition system coupled to said optical signal reception device and to said reference signal memory to determine said reference channel response signal from a received optical signal and to store said determined reference in said reference signal memory.

3. An optical data communications receiver as claimed in claim 2 wherein said reference signal acquisition system is configured to acquire a plurality of said reference channel response signals from a plurality of different optical transmitters and to store said plurality of reference channel response signals in said reference signal memory.

4. An optical data communications receiver as claimed in claim 1 wherein said reference channel response signal comprises a plurality of multipath components.

5. An optical data communications receiver as claimed in claim 4 wherein said reference signal memory has a data structure defining said channel response signal as at least two said multipath components separated by a delay.

6. An optical data communications receiver as claimed in claim 4 wherein said correlator includes partial correlation storage to accumulate a plurality of partial correlations for said multipath components to thereby correlate interleaved multipath components of successively transmitted optical pulses.

7. An optical data communications receiver as claimed in claim 1 wherein said correlator is configured to correlate, within a time window, a plurality of samples of said received optical pulse with a plurality of samples of stored reference channel response signal.

8. An optical data communications receiver as claimed in claim 1 comprising a plurality of said correlations coupled to said reference signal memory and to said signal reception device at successive respective relative delays between said stored reference channel response signal and said received optical pulse to determine said optical pulse position.

9. An optical data communications receiver as claimed in claim 1 wherein said optical pulse position is modulated by a pseudorandom sequence, the receiver further comprising a pseudorandom sequence generator for tracking said pseudorandom modulation.

10. An optical data communications receiver as claimed in claim 9 wherein said sequence generator is coupled to one or both of said reference signal memory and said correlator for correlating said received optical pulse with said stored reference channel response signal at positions in time determined by said pseudorandom sequence.

11. An optical data communications receiver as claimed in claim 10 wherein said correlator is configured for correlating at at least two said positions in time in parallel, each of said two positions corresponding to a possible value of an encoded bit of said data.

12. An optical data communications receiver as claimed in claim 9 wherein said data comprises packet data, a packet of said data including a header with data for identifying one or both of a pseudorandom sequence identifier and a pseudorandom sequence seed, and wherein said receiver further comprises a system coupled to said pseudorandom sequence generator for reading said packet header to determine data for initialising said pseudorandom sequence generator.

13. An optical data communications receiver as claimed in claim 1 having a receiver front end including said optical signal reception device, and said front end further comprising an analogue-to-digital (A/D) converter coupled between an output of said optical signal reception device and said correlator.

14. An optical data communications receiver as claimed in claim 13 wherein said front end is configured to implement a peak detect Function for said optical signal reception device.

15. An optical data communications receiver as claimed in claim 14 wherein said A/D converter has a non-linear conversion Function to implement said peak detect Function.

16. An optical data communications receiver as claimed in claim 13 wherein said A/D converter has an offset to implement a peak detect Function.

17. An optical data communications receiver as claimed in claim 13 wherein said A/D converter comprises a one bit A/D converter.

18. An optical data communications receiver as claimed in claim 13 wherein said receiver front end further comprises a received signal level adjuster to adjust an input signal to said analogue-to-digital converter.

19. An optical data communications receiver as claimed in claim 18 wherein said received signal level adjuster is responsive to said reference channel response signal.

27. A passive optical network including one or more optical data communications receivers as claimed in claim 1.

20. An optical data communications receiver for receiving data encoded using optical pulse position, the receiver comprising:

an optical signal reception device;

a correlator coupled to said optical signal reception device for determining a received optical pulse position;

an output coupled to said correlator to provide pulse position data for said received optical pulse; and

wherein said optical pulse position is modulated by a pseudorandom sequence, the receiver further comprising a pseudorandom sequence generator for tracking said pseudorandom modulation.

21. An optical data communications receiver as claimed in claim 20 further comprising a reference signal memory for storing a reference channel response signal, and wherein said sequence generator is coupled to one or both of said reference signal memory and said correlator for correlating said received optical pulse with said stored reference channel response signal at positions in time determined by said pseudorandom sequence.

22. An optical data communications receiver comprising:

a receiver front end including an optical signal reception device coupled to an analogue-to-digital (A/D) converter to digitise an optical signal received by said optical signal reception device; and

a correlator coupled to said A/D converter to correlate said digitised received optical signal with a reference to decode said received optical signal.

23. An optical data communications receiver as claimed in claim 22 wherein said front end is configured to implement a peak detect Function for said optical signal reception device.

24. An optical data communications receiver as claim in claim 22 wherein said A/D converter has an offset to implement a peak detect Function.

25. An optical data communications receiver, the receiver comprising:

an optical signal reception device having an output; and

a UWB receiver system coupled to said output of said optical signal reception device.

26. An optical data communications receiver as claimed in claim 25 wherein said UWB receiver system is configured to perform a peak detect function on said optical signal reception device output.

28. An optical mesh network, the network comprising a plurality of optical transceivers, each said transceiver comprising an optical data communications transmitter configured to modulate data to be transmitted onto an optical output of the transceiver and an optical data communications receiver configured to receive an optical signal and to demodulate said received signal to recover transmitted data, and wherein transmitter is configured to spread said transmitted data using a pseudorandom sequence, and wherein said receiver in configured to despread said received optical signal to recover said transmitted data.

29. An optical mesh network as claimed in claim 28 wherein said transmitted data is pulse position modulated on said optical signal.

30. An optical data communications transmitter for transmitting data encoded using optical pulse position, the transmitter including a pseudorandom sequence generator for imposing a pseudorandom spreading code on said pulse positions encoding said data for transmitting.

31. A method of optical data communications, the method comprising:

inputting data to be transmitted;

pulse position modulating said data onto an optical signal;

sending said optical signal to an optical receiver;

receiving said optical signal at said receiver; and

demodulating said received optical data; and

the method further comprising spreading said modulated pulse positions according to a pseudorandom sequence to reduce susceptibility of the communicated data to systematic noise.

32. An optical data communications system, the system comprising:

an output for data to be transmitted;

a pulse position modulator for pulse position modulating said data onto an optical signal;

an optical transmitter to transmit said optical signal;

an optical receiver to receive said transmitted optical signal; and

a demodulator for demodulating said received optical data to recover said transmitted data; and

wherein the system further comprises

a spreader for spreading said modulated pulse positions according to a pseudorandom sequence to reduce susceptibility of the communicated data to systematic noise.

33. A dual-capability transceiver system for networking, the transceiver having dual optical/UWB data communication capability, the transceiver including:

an interface for optical emitter/detector;

an interface for rf emitter/detector; and

a UWB signal processor coupled to said rf emitter/detector interface for sending and receiving radio frequency (rf) UWB transmissions and having UWB signal processing hardware for processing received UWB transmissions to retrieve communicated data; and

wherein

said optical emitter/detector interface shares at least a portion of said UWB signal processing hardware for processing received optical transmissions to retrieve optically communicated data.

34. A transceiver as claimed in claim 33 wherein said optical data communication capability and said UWB data communication capability each comprise a data communication capability in excess of 100 Mbps.

35. A network of consumer electronic devices, at least some of said consumer electronic devices including a transceiver as claimed in claim 33.

36. A network as claimed in claim 35 wherein said optical data communication capability comprises an infrared (IR) data communication capability.