Abstract:
Apparatus for controlling one or more light sources to emit coded light which is modulated to embed a signal. The apparatus comprises: an interface for receiving information relating to two or more exposure times of one or more cameras on one or more devices, the one or more cameras being operable to detect the coded light based on the modulation; and a controller configured to select at least one property of the modulation, based on the information, such that the modulation is detectable at each of said two or more exposure times.
Abstract:
Techniques are disclosed for providing light-based communication (LCom) between a receiver device and one or more transmitting LCom-enabled luminaires. In accordance with some embodiments, LCom data to be transmitted may be allocated over multiple colors of light output by multiple LCom-enabled luminaires and transmitted in parallel across the multiple colors of light using a time division multiple access (TDMA) scheme. In some cases, the disclosed techniques can be used, for example, to allow for multiple LCom-enabled luminaires to communicate simultaneously over multiple active LCom channels with a single receiver device. In some instances, the disclosed techniques may be used, for example, to provide channel redundancy that facilitates successful completion of LCom data transmission when an LCom channel is broken. In some instances, the disclosed techniques may be used, for example, to provide more accurate positioning for indoor navigation.
Abstract:
Techniques are disclosed for providing proper raster line alignment of a camera or other light-sensing device of a receiver device relative to a transmitting light-based communication (LCom)-enabled luminaire to establish reliable LCom there between. In accordance with some embodiments, proper alignment can be provided automatically (e.g., by the receiver device and/or other suitable controller). In accordance with some embodiments, proper alignment can be provided by the user. In some instances in which a user is to be involved in the alignment process, the receiver device may be configured, for example, to instruct or otherwise guide the user in the process of properly aligning the receiver device relative to a given transmitting LCom-enabled luminaire.
Abstract:
The invention relates to an optical receiver (102) adapted for receiving via a transmission channel an orthogonal frequency-division multiplex optical signal via a plurality of subcarriers. The optical receiver comprises means for performing channel estimation (150) and means for performing equalization (126) on the basis of coefficients representative of the transmission channel, said coefficients being provided by said means for performing channel estimation. The means for performing channel estimation comprise: means for processing a training sequence (151,152,153) received via a first subset among said plurality of subcarriers; and means for interpolating coefficients (160), the interpolated coefficients corresponding to subcarriers not processed by said means for processing the training sequence.
Abstract:
A fiber optic communication system comprising: an optical signal source adapted to receive a binary first signal and generate a binary second signal, wherein the binary first signal has an amplitude modulated component, wherein the binary second signal has an amplitude modulated component and a frequency modulated component, and further wherein the binary second signal is characterized in that the higher intensity 1 bits are red shifted relative to the lower intensity 0 bits; a semiconductor optical amplifier (SOA) adapted to receive the binary second signal and generate a binary third signal, wherein the binary third signal has an amplitude modulated component and a frequency modulated component, and further wherein the semiconductor optical amplifier operates in saturation; and an optical spectrum reshaper (OSR) adapted to reshape the binary third signal into a binary fourth signal, wherein the binary fourth signal has an amplitude modulated component and a frequency modulated component. A method for transmitting a signal, comprising: receiving a binary first signal having an amplitude modulated component and generating a binary second signal having an amplitude modulated component and a frequency modulated component, wherein the binary second signal is characterized in that the higher intensity 1 bits are red shifted relative to the lower intensity 0 bits; passing the binary second signal through a semiconductor optical amplifier (SOA) operating in saturation so as to generate a binary third signal, wherein the binary third signal has an amplitude modulated component and a frequency modulated component; and reshaping the binary third signal into a binary fourth signal, wherein the binary fourth signal has an amplitude modulated component and a frequency modulated component.
Abstract:
A method (10) of transmitting communications traffic, the method comprising steps of receiving a sequence of communications traffic bits (12); and mapping the sequence of communications traffic bits onto a respective one of a plurality of transmission symbols for transmission during a symbol time (14). Each transmission symbol is identified by a respective first symbol identifier indicative of a respective one or more of a plurality, M, of wavelengths for a transmission signal and a respective second symbol identifier indicative of a respective one or more of a plurality, N, of optical fibres on which to transmit the transmission signal.
Abstract:
Techniques are disclosed for emitting position information from luminaires. Luminaire position information may be emitted via light-based communication (LCom) signal that comprises data including the position information. The data may include relative and/or absolute position information for the luminaire and may indicate the physical location of the luminaire. Relative position information for the luminaire may include coordinates relative to a point of origin within the environment. Absolute position information for the luminaire may include global coordinates for the luminaire. In some cases, the absolute position information for a luminaire may be calculated using position information for the luminaire relative to a point of origin and the absolute position of the point of origin. The data may also include an environment identifier, which may indicate a map to use for the interpretation of position information for the luminaire. The techniques can be used for both stationary and mobile luminaires.
Abstract:
An apparatus comprises a digital signal processing module configured to receive a data stream and generate a plurality of digital multiple tones, a plurality of digital-to-analog converters coupled to the digital signal processing module, a plurality of drivers coupled to respective digital-to-analog converters, an electro-optic modulator having inputs coupled to the drivers and outputs coupled to a fiber and a multi-wavelength light source coupled to the electro-optic modulator.