IEEE802.15.7-2011 standard(一)

color function: A function that provides information, such as device status and channel quality, to the

human eye via color.

color-shift keying (CSK): A modulation scheme for visible-light communication involving multiple light

sources, which keeps the average emitted optical color and the total optical power constant during

communication.

color stabilization: A control loop for the stabilization of the color emitted by color-shift-keying

transmitters.

color visibility dimming (CVD) frame: A frame used for color, visibility and dimming support. The color

visibility dimming frame visually provides information such as communication status and channel quality to

the user via various colors. The color visibility dimming frame may also be sent during idle or receive

modes of operation for continuous visibility and dimming support. During the color visibility dimming

frame transmission, the device is still emitting light while not communicating, and it is thus able to fulfill its

lighting function. The payload of the frame consists of visibility patterns of appropriate intensity and color.

compensation time: The idle time inserted in the idle pattern or in the data frame, where the light is turned

“ON” or “OFF” with the appropriate ratio to meet dimming requirements.

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OPTICAL COMMUNICATION USING VISIBLE LIGHT IEEE Std 802.15.7-2011

Copyright ? 2011 IEEE. All rights reserved. 3

dimming: Reducing the radiant power of a transmitter while preserving the color of the transmitted light.

field of view (FOV): The angular extent of coverage for the optical transmitter or receiver.

idle pattern: A pattern whose duty cycle variation results in a change of brightness for dimming support and

may be transmitted during idle or receive mode.

macro cell: An aggregate cell formed using all the cells available at the optical media and is used for device

discovery and association.

modulation-domain spectrum: The spectrum observed at the output of the receiver’s photodetector;

typically measured at the output of the trans impedance amplifier

on-off keying (OOK): A simple modulation technique that represents digital data as the presence (‘ON’) or

absence (‘OFF’) of a signal. Note that ‘ON’ and ‘OFF’ are simply two logic levels or two distinct amplitude

levels for the purposes of communication and does not necessarily require that the light source be turned

OFF completely.

optical clock rate: The frequency at which the data is clocked out to the optical source.

photodetector: A photodetector captures optical power and translates it into an output signal. Most

photodetectors convert optical power into an electrical current or an electrical voltage.

PHY switch: A switch at the transmission interface between the PHY and the optical SAP, used to send and

receive data to and from a single or multiple optical sources and photodetectors in a selective manner.

point-and-shoot: The alignment of devices by the transmission of a color visibility dimming frame for the

purpose of illuminating the target receiving device.

switching level: A distinct amplitude level that defines ‘ON’ and ‘OFF’ of the light source for the purpose

of communications and does not necessarily require that the light source be turned off completely.

variable pulse-position modulation (VPPM): A modulation scheme for visible-light communication that

allows pulse-width control for light dimming support, mitigating intra-frame flicker.

visibility pattern: An in-band idle pattern used in the payload of a color visibility dimming frame.