Multiphase sampling of modulated light with phase synchronization field
AssigneeIntel Corporation
InventorRichard D. Roberts
Life of this patent
Estimating the term…
Abstract
A light transmitter transmits multiple light packets, each formatted to include a predetermined phase synchronization field (PSF) and a same message comprising a series of bits. The PSF and each bit are each represented as light that is intensity modulated over a bit period at a corresponding frequency. The light packets are transmitted at different start-times to cause a receiver to sample each packet with a different phase of a fixed, asynchronous sample timeline. The PSF and message are demodulated from each of the sampled light packets. If the demodulated PSF matches the predetermined PSF, then the corresponding demodulated message is declared valid.
Claims29
An apparatus, comprising a light transmitter configured to:
- encode an identical message in each of first and second light packets, including, for each light packet, to cycle an intensity of a light source at one of first and second frequencies for each bit of a message based on a value of the respective bit, and cycle the intensity of the light source at one of the first and second frequencies to encode a predetermined logic value in a phase synchronization field (PSF) of a start frame delimiter (SFD) portion of the light packet;
- and
- transmit the first and second light packets with a phase difference between the PSF and the message of the second light packet and the PSF and the message of the first light packet, wherein the phase difference is relative to a receiver sample rate.
A non-transitory computer readable medium encoded with a computer program that includes instructions to cause a processor to:
- encode an identical message in each of first and second light packets, including, for each light packet, to cycle an intensity of a light source at one of first and second frequencies for each bit of a message based on a value of the respective bit, and cycle the intensity of the light source at one of the first and second frequencies to encode a predetermined logic value in a phase synchronization field (PSF) of a start frame delimiter (SFD) portion of the light packet;
- and
- transmit the first and second light packets with a phase difference between the PSF and the message of the second light packet and the PSF and the message of the first light packet, wherein the phase difference is relative to a receiver sample rate.
A method, comprising:
- encoding an identical message in each of first and second light packets, including, for each light packet, cycling an intensity of a light source at one of first and second frequencies for each bit of a message based on a value of the respective bit, and cycling the intensity of the light source at one of the first and second frequencies to encode a predetermined logic value in a phase synchronization field (PSF) of a start frame delimiter (SFD) portion of the light packet the light packet;
- and
- transmitting the first and second light packets with a phase difference between the PSF and the message of the second light packet and the PSF and the message of the first light packet, wherein the phase difference is relative to a receiver sample rate.
An apparatus, comprising a light receiver configured to:
- sample each of first and second light packets at receiver sample rate;
- demodulate a logic value of a phase synchronization field (PSF) of each of the first and second light packets based on samples of the respective light packet;
- demodulate a message portion of each of the first and second light packets based on samples of the respective light packet;
- and
- validate the demodulated message portion of one or more of the first and second light packets if the demodulated logic value of the respective light packet PSF corresponds to a predetermined logic value.
Dependencies are inferred from the claim text.