Abstract: A coding scheme for a colour-shift-keying constellation in a visible-light communication system is provided, whereby a minimum number of flipped bits between symbols assigned to neighbouring symbol points in the constellation is aimed. Improved assignments of symbol values to symbol points of the constellation may be provided, which may be capable of reducing a total Hamming distance between all symbol points in the constellation, thereby leading to a reduction of a bit-error ratio.

Abstract: In a method and an apparatus for the optical transmission of data by a pulse-width modulated light source (LED), in which a set dimming factor (N) is replaced with a cycle-dependent dimming factor (NI), the cycle-dependent dimming factor is modulated for encoding the data to be transmitted and corresponds to the set dimming factor over a time interval which is resolvable for the human eye.

Abstract: In a method for transmission of digital data in an optical free-space transmission system in which a binary code sequence produced from the digital data is used to transmit amplitude-modulated light waves across an optical free space between a transmitter and a receiver, according to a first aspect, the binary code sequence is produced such that a modulation frequency of the light waves determined by the binary code sequence has a value of 70 Hertz. According to a second aspect, ‘t’ light waves are modulated with the binary code sequence and binary data are transmitted in blocks during a first time period, and non-modulated light waves are emitted during second time periods, wherein the light intensities of the time periods are selected so that the quantities of light transmitted in two periods correspond to predetermined quantities of light.

Abstract: A method for optically transmitting data between a transmitter and a receiver is disclosed, in which a colour coding method based on a plurality of elemental colours is provided for the coding and transmission of the data, which colour coding method involves a respective elemental colour being sent by a respective transmitter-end optical radiation source and being received at the receiver end by a respective optical radiation receiver. The method provides for a control loop to be formed between the transmitter and the receiver, wherein the transmitter sends calibration messages to the receiver, and wherein a piece of compensation information is ascertained by comparing at least one channel property of at least one received calibration message with a corresponding channel property of at least one previously sent calibration message, and wherein the transmitter takes the compensation information as a basis for adjusting at least one transmission parameter.

Abstract: A method for optically transmitting data between a transmitter and a receiver is provided, wherein a color coding method based on a plurality of elementary colors is provided for encoding and transmitting the data, wherein each elementary color is transmitted by a transmitter-side optical radiation source and is received on the receiver side by an optical radiation receiver. The method includes transmitting a training request message comprising calibration information formed on the transmitter side; forming a channel properties matrix by the receiver from the calibration information and storing the channel properties matrix in the receiver; calculating at least one compensation information on the basis of a reference channel properties matrix stored in the receiver and the reference channel properties matrix; and transmitting the compensation information from the receiver to the transmitter.

Abstract: An amplifier circuit for actuating a light diode is provided. The amplifier circuit may have a small output impedance of approximately 3 Ohms, a large bandwidth having a lower threshold frequency of 200 kHz and an upper threshold frequency of 5 MHz, for example, and an amplitude of the output current of several 100 mA, for example. The amplifier circuit may have an entry stage for actuating a driver circuit that actuates the light diode by means of a direct current supply.

Abstract: A method is provide for optically transferring data between a transmitter and a receiver employs a color coding method based on a plurality of elementary colors for encoding and transferring the data. Each elementary color is transmitted by one optical radiation source each on the transmitter side, and is received on the receiver side by one optical radiation receiver each. A control loop is formed between the transmitter and the receiver, wherein calibration messages are sent by the transmitter to the receiver, and wherein compensation information is determined by means of comparing at least one channel property of at least one received calibration message to a corresponding channel property of at least one previously transmitted calibration message, and wherein an adjustment of at least one transmitting parameter is made in the transmitter on the basis of the compensation information.

Abstract: In a method for optically transmitting data by means of a pulse-width-modulated light source (LED), a pulse duty factor (N) of a pulse width modulation is specified to set the brightness of the light source (LED). A bright time (T) is divided into at least a first and second partial bright time using at least one blanking so that the data (DATA) to be transmitted are encoded by the start and time length of the at least one blanking. The sum of the partial bright times within the pulse width modulation cycle substantially corresponds to the bright time according to the specified pulse duty factor.

Abstract: In a method and an apparatus for the optical transmission of data by a pulse-width modulated light source (LED), in which a set dimming factor (N) is replaced with a cycle-dependent dimming factor (NI), the cycle-dependent dimming factor is modulated for encoding the data to be transmitted and corresponds to the set dimming factor over a time interval which is resolvable for the human eye.

Abstract: A key with a key light function comprising at least one light source (5), a storage circuit (20) for storing at least one code sequence, and a driver unit (10), which converts the stored form of the code sequence into a driving output for the light source (5), wherein the code sequence can be emitted by the light source (5) at a wavelength visible to humans by means of a temporal or color variation of the luminous flux, and the light source (5) can also be used as an orientation light.

Abstract: In a method for operating a wireless sensor network (1) with a plurality of sensor nodes (2-4), which are suitably set up to transmit data by nondirectional radio transmission, a selected set containing at least one sensor node (2) can be selectively moved from a first operating state into a second operating state by a spatially delimited first operating state control signal (17), with the sensor node (2-4) in the first operating state not being able to receive control data by nondirectional radio transmission and in the second operating state, being able to receive and process control data by nondirectional radio transmission. Furthermore, a sensor node can be suitably configured to implement the method.

Abstract: In a device and method for the optical transmission of data using a pulse-width-modulated LED (2), a startup phase ascertainment unit (3) for ascertaining at least one startup phase of the LED (2) as a function of a sequence of detected switching states of the LED (2) and a modulation unit (4) for modulating the data to a light signal emitted by the LED (2) during the ascertained startup phase of the LED (2) are provided, and data packets are first deleted from the data packet queue or queues after they have been successfully transmitted.

Abstract: In a method for transmission of digital data in an optical free-space transmission system in which a binary code sequence produced from the digital data is used to transmit amplitude-modulated light waves across an optical free space between a transmitter and a receiver, according to a first aspect, the binary code sequence is produced such that a modulation frequency of the light waves determined by the binary code sequence has a value of 70 Hertz. According to a second aspect, ‘t’ light waves are modulated with the binary code sequence and binary data are transmitted in blocks during a first time period, and non-modulated light waves are emitted during second time periods, wherein the light intensities of the time periods are selected so that the quantities of light transmitted in two periods correspond to predetermined quantities of light.

Abstract: A data transmission system has a light-emitting transmitter, a light-receiving receiver and a data transmission channel based on incoherent light. A pre-equalization device connected upstream of the transmitter is provided for the purpose of pre-equalizing a data signal which is to be transmitted from the transmitter to the receiver via the data transmission channel. The data transmission channel has constant transmission conditions within prescribed limits. The data signal to be transmitted is transmitted using a prescribed maximum bandwidth of the transmitter.

Abstract: The present embodiments relate to non-contact transmission of optical signals by an optical waveguide which is provided with a material of which the electron arrangement is able to be put into population inversion. In a first variant, energy is fed to the optical waveguide so that the electron arrangement is held in a state above its thermal equilibrium and below the population inversion, with optical signals being beamed into the optical waveguide with a wavelength exciting the electrons of the inversion material such that a local population inversion is created in a section of the optical waveguide, and subsequently light which is created by spontaneous emission is detected. In a second variant, a local population inversion is created by pump light, with simultaneously optical signals being beamed into the population-inverted section with the emission wavelength and by light created by stimulated emission being detected.