Laser systems are provided with a semiconductor laser having an emission face, a drive circuit adapted to supply electric energy to the semiconductor laser to cause the semiconductor laser to emit a beam; a user input system adapted to sense a user input action; a controller adapted to control the drive circuit based upon the sensed user input action; a housing within which the laser is positioned and having an opening with a window through which the semiconductor laser can emit the beam. The semiconductor laser is positioned to emit the beam through the window and the emission face of the semiconductor laser is sized to cause a divergence in the beam to create a patterned emission with a predetermined shape without passing the beam through beam shaping optics.

The present specification provides a method and apparatus, the method being for transmitting a beam, performed by the apparatus, in an optical wireless communication system, and comprising: generating a pulse laser signal; making the pulse laser signal to be incident on a metasurface, wherein the beam is generated on the basis that the pulse laser signal is incident on the metasurface; and transmitting the beam to a reception apparatus, wherein the metasurface is determined on the basis of ω_0, d, Δω, and N, wherein ω_0 is a value of a center frequency, d is a value of a virtual antenna interval, Δω is a value of a frequency comb interval, and N is a value related to the number of frequency combs present within a gain bandwidth based on the center frequency.

The present specification provides a method and apparatus, the method being for transmitting a beam, performed by the apparatus, in an optical wireless communication system, and comprising: generating a pulse laser signal; making the pulse laser signal to be incident on a metasurface, wherein the beam is generated on the basis that the pulse laser signal is incident on the metasurface; and transmitting the beam to a reception apparatus, wherein the metasurface is determined on the basis of ω_0, d, Δω, and N, wherein ω_0 is a value of a center frequency, d is a value of a virtual antenna interval, Δω is a value of a frequency comb interval, and N is a value related to the number of frequency combs present within a gain bandwidth based on the center frequency.

According to an example aspect of the present invention, there is provided an apparatus comprising a first part (110) which comprises a first light-based communication port (114) and a network interface (112), a second part (120) which comprises a non-volatile memory (122) and a second light-based communication port (124), and wherein the apparatus is configured to deactivate at least one of the first light-based communication port (114) and the second light-based communication port (124) responsive to determining that a read or write operation in the non-volatile memory (122) is complete.

A signal receiving apparatus includes at least one signal separating apparatus that separates a specific signal from a plurality of received signals. Each of the at least one signal separating apparatus includes a spatial filtering unit that separates at least one equalized signal and a decision signal outputting unit that generates a first decision signal by deciding the equalized signal and outputs the generated first decision signal. The spatial filtering unit separates the at least one equalized signal by multiplying at least the plurality of received signals among the plurality of received signals and either the first decision signal output from the decision signal outputting unit or a second decision signal output from another signal separating apparatus by predetermined weighting coefficients.

Data transceiving electronic device (100), configured to permit the establishment of at least a communication with at least an electronic device (301; 302) remotely positioned with respect to the data transceiving electronic device (100), said data transceiving electronic device (100) comprises a radio frequency module (105) configured to receive and transmit electronic data on a wireless channel according to at least a predefined first wireless communication standard, and an optical transceiver module (108) in turn comprising at least an optical transmitter (109) and an optical receiver (110); said data transceiving electronic device (100) being configured to select said optical transceiver module (108) as the preferential priority module for the establishment of said communication with said at least one electronic device (301; 302).

Data transceiving electronic device (100), configured to permit the establishment of at least a communication with at least an electronic device (301; 302) remotely positioned with respect to the data transceiving electronic device (100), said data transceiving electronic device (100) comprises a radio frequency module (105) configured to receive and transmit electronic data on a wireless channel according to at least a predefined first wireless communication standard, and an optical transceiver module (108) in turn comprising at least an optical transmitter (109) and an optical receiver (110); said data transceiving electronic device (100) being configured to select said optical transceiver module (108) as the preferential priority module for the establishment of said communication with said at least one electronic device (301; 302).

Synchronizing a pulse position modulation (PPM) signal. A method includes performing a first synchronization operation by receiving a first series of symbols. The symbols in the first series are transmitted with a pulse in a known slot, such that the symbols comprise pulses that are substantially equally spaced in time from adjacent symbols. The first synchronization operation includes identifying when each pulse is received for each of the symbols and using information identifying when each pulse is received for each of the symbols in the first series of symbols to identify symbol and slot boundaries for the pulse position modulation signal. The method further includes performing a second synchronization operation by receiving a second series of symbols transmitted in a known pattern, and identifying the known pattern in the received second series of symbols to identify a frame boundary.

Synchronizing a pulse position modulation (PPM) signal. A method includes performing a first synchronization operation by receiving a first series of symbols. The symbols in the first series are transmitted with a pulse in a known slot, such that the symbols comprise pulses that are substantially equally spaced in time from adjacent symbols. The first synchronization operation includes identifying when each pulse is received for each of the symbols and using information identifying when each pulse is received for each of the symbols in the first series of symbols to identify symbol and slot boundaries for the pulse position modulation signal. The method further includes performing a second synchronization operation by receiving a second series of symbols transmitted in a known pattern, and identifying the known pattern in the received second series of symbols to identify a frame boundary.

Methods for building, transmitting, and receiving frame structures in power line communications (PLC) are described. Various techniques described herein provide a preamble design using one or more symbols. One or more preamble symbols may be interspersed within a header portion of a PLC frame to facilitate estimation of a frame boundary and/or sampling frequency offset, for example, in the presence of impulsive noise.