Abstract: The present invention is related to an apparatus and method for determining the location of a communication device within a wireless network in order to provide a geolocation functionality to the communication device participating under an access protocol of a wireless local-area network (WLAN) infrastructure such as IEEE 802.11 or Hiperlan. The apparatus comprises at least two transponder units for communicating with the communication device when the communication device is situated in a coverage area of the wireless network and a processing unit for deriving the location of the communication device within the coverage area in dependence on information received from the transponder units.

Abstract: The present invention is related to an apparatus and method for determining the location of a communication device within a wireless network in order to provide a geolocation functionality to the communication device participating under an access protocol of a wireless local-area network (WLAN) infrastructure such as IEEE 802.11 or Hiperlan. The apparatus comprises at least two transponder units for communicating with the communication device when the communication device is situated in a coverage area of the wireless network and a processing unit for deriving the location of the communication device within the coverage area in dependence on information received from the transponder units.

Abstract: The invention relates to a conversion of a pulse modulated signal to a radio frequency signal enabling use of applications and protocols designed for wireless optical links on radio frequency channels. The method comprises receiving the pulse modulated input signal, decoding the received pulse modulated input signal into a decoded data bit-stream, encoding the decoded data bit-stream into a recoded data bit-stream, under use of the recoded data bit-stream modulating a radio frequency signal, and transmitting the modulated radio frequency signal. In the receiver path a received radio frequency signal is converted to a pulse modulated output signal by the steps of demodulating the received radio frequency signal into a demodulated data bit-stream, decoding the demodulated data bit-stream into a received data bit-stream, encoding the received data bit-stream into a pulse modulated output signal, and forwarding the pulse modulated output signal.

Abstract: The present invention is related to an apparatus and method for determining the location of a communication device within a wireless network in order to provide a geolocation functionality to the communication device participating under an access protocol of a wireless local-area network (WLAN) infrastructure such as IEEE 0.802.11 or Hiperlan. The apparatus comprises at least two transponder units for communicating with the communication device when the communication device is situated in a coverage area of the wireless network and a processing unit for deriving the location of the communication device within the coverage area in dependence on information received from the transponder units.

Abstract: The invention relates to a conversion of a pulse modulated signal to a radio frequency signal enableing use of applications and protocols designed for wireless optical links on radio frequency channels. The method comprises receiving the pulse modulated input signal, decoding the received pulse modulated input signal into a decoded data bit-stream, encoding the decoded data bit-stream into a recoded data bit-stream, under use of the recoded data bit-stream modulating a radio frequency signal, and transmitting the modulated radio frequency signal. In the receiver path a received radio frequency signal is converted to a pulse modulated output signal by the steps of demodulating the received radio frequency signal into a demodulated data bit-stream, decoding the demodulated data bit-stream into a received data bit-stream, encoding the received data bit-stream into a pulse modulated output signal, and forwarding the pulse modulated output signal.

Abstract: An apparatus and method for setting a transfer rate of information units in a variable data-rate transmission scheme for a wireless communication system is disclosed. For that, a total counter for counting a total number of received information units, an error counter for counting an error number of received invalid information units, a division unit for dividing the error number by the total number, and a decision unit for setting a transmission-rate parameter are utilizable. The division result is providable as a link-quality measure at an output of the division unit. This link-quality measure is comparable with at least one predefined value depending on the result of which, the transmission-rate parameter is setable.

Abstract: The present invention is related to an apparatus and method for determining the location of a communication device within a wireless network in order to provide a geolocation functionality to the communication device participating under an access protocol of a wireless local-area network (WLAN) infrastructure such as IEEE 0.802.11 or Hiperlan. The apparatus comprises at least two transponder units for communicating with the communication device when the communication device is situated in a coverage area of the wireless network and a processing unit for deriving the location of the communication device within the coverage area in dependence on information received from the transponder units.

Abstract: An apparatus and method for determining the quality of a digital signal. The incoming digital signal is sampled with a number n of samples per defined pulse width, where N is greater than or equal to one, using clock cycles. An edge detector detects the edge position of a pulse of the sampled digital signal and a counter counts the clock cycles between at least a first edge and a second edge detected by the edge detector. A deviation detector then compares the counted clock cycles with a prestored reference-value in order to provide a deviation value as a measure for the instantaneous quality of the digital signal. The deviation value is then fed to a rework unit that outputs a value that is a measure for the quality of the digital signal.

Abstract: The present invention provides an apparatus and a method for determining a pulse position for a signal encoded by a pulse modulation. The signal being receivable as at least a first component (PCS) and a second component (DCS). A first storage unit (102) stores at least one symbol of the first component (PCS) and a second storage unit (104) at least one symbol of the second component (DCS). A determination unit (118) comprises a probability table (110), which in case that the first and second components (PCS, DCS) are received is addressed with the at least one symbol of the first component (PCS) and the at least one symbol of the second component (DCS). Thereby, the probability table (110) provides a value that is defined as the pulse position (DDS).

Abstract: The present invention provides an apparatus and a method for improved connectivity in wireless optical networks. Therefore at least two or more receiving units are used which receive an infrared signal and convert it to a digital signal. The digital signals represent data in the form of frames whereby each frame comprises at least a data field and a header field containing a preamble. A selector determines a measure related to the signal-to-noise ratio of the preamble and compares the measures in order to select the best suited signal for further processing.

Abstract: The present invention provides apparatus and methods for determining a propagation time of a signal transmitted from a first location to a second location as a request signal and received as a response signal by the first location via a channel. In an example embodiment, a method comprises the step of determining the propagation time of the signal based on a local counter value that represents the time between transmission of the request signal and reception of the response signal, a remote counter value that depends on the request signal and being known to the first location, and a determinable time-delay value. The remote counter value represents an inter-time-delay between the reception of the request signal and the start of transmission of the response signal at the second location.

Abstract: The present invention provides apparatus and methods for determining a propagation time of a signal transmitted from a first location to a second location as a request signal and received as a response signal by the first location via a channel. In an example embodiment, a method comprises the step of determining the propagation time of the signal based on a local counter value that represents the time between transmission of the request signal and reception of the response signal, a remote counter value that depends on the request signal and being known to the first location, and a determinable time-delay value. The remote counter value represents an inter-time-delay between the reception of the request signal and the start of transmission of the response signal at the second location.

Abstract: Disclosed are optical transmitter and transceiver modules for data communication. Such a transceiver module comprises an array of light emitting diodes mounted on a mounting base (140) being arranged in a regular and symmetrical manner in a dome-shaped housing (142). This housing (142) comprises diffusor means for source enlargement. In addition to the transmitter part consisting of said diodes, the transceiver module comprises a receiver. The receiver has four photodiodes (143) arranged below the mounting base (140). These photodiodes are tilted and face in different directions to receive light from all around the module. The photodiodes are protected by a thin wire mesh (145) which serves as Faraday cage to reduce electro magnetic interference. A substrate (144) for electronic circuitry in SMD-Technology is situated underneath the photodiodes (143).

Abstract: The invention involves an optical wireless communication system comprising a transmitter and a receiver wherein the transmitter has a three-dimensional optical emission characteristic and the receiver has a three-dimensional optical reception characteristic. According to the present invention, the shape of the optical emission characteristic matches the shape of the optical reception characteristic at least within one two-dimensional plane.

Abstract: The present invention provides an apparatus and method for determining the quality of a digital signal (S). The incoming digital signal (S) is sampled with a number n of samples per defined pulse width, whereby n≧1, using clock cycles (CLK). In the following, an edge detector (20) detects the edge position of a pulse of the sampled digital signal and a counter (30) counts the clock cycles between at least a first edge and a second edge detected by the edge detector. A deviation detector (40) then compares the counted clock cycles (EEC) with a prestored reference-value (EEC0) in order to provide a deviation value (RJ) as a measure for the instantaneous quality of the digital signal (S). This deviation value (RJ) is then fed to a rework unit that outputs a value (J) that is a measure for the quality of the digital signal.

Abstract: The present invention provides an apparatus and a method for determining a pulse position for a signal encoded by a pulse modulation. The signal being receivable as at least a first component (PCS) and a second component (DCS). A first storage unit (102) stores at least one symbol of the first component (PCS) and a second storage unit (104) at least one symbol of the second component (DCS). A determination unit (118) comprises a probability table (110), which in case that the first and second components (PCS, DCS) are received is addressed with the at least one symbol of the first component (PCS) and the at least one symbol of the second component (DCS). Thereby, the probability table (110) provides a value that is defined as the pulse position (DDS).

Abstract: The wireless optical (in particular infrared) communication system with at least one transmitter (75) and one receiver (76) comprises control means (77, 78), which dynamically adapt the data rate and/or the optical power of the transmitter in dependence of signal-to-noise ratio of the receiver. Due to this adjustment, optimized system performance is maintained even under the influence of ambient light which statistically changes the signal-to-noise ratio of the receiver. The best compromise between data rate, bit error rate and transmission range is dynamically determined. The control function is distributed between transmitting and receiving system unit. The control information is communicated via wireless optical communication.

Abstract: A semiconductor laser diode comprises a waveguide formed by an active layer sandwiched in between upper and lower cladding layers, wherein the cladding layers comprise a material having a bandgap that differs from that of the active layer. The waveguide is deposited on a structured substrate having a surface pattern that causes the waveguide to be bent near its ends, i.e., near cleaved or etched facets of the completed laser device thereby providing a non-absorbing mirror (NAM) window structure. A laser beam, generated in the center, planar waveguide section, leaves the waveguide at the bend, continuing substantially unabsorbed and undeflected through the wider bandgap cladding layer material towards the mirror facet. An amphoteric dopant, used during growth of the layered waveguide structure, causes a reversal of the conductivity-type within the semiconductor material deposited above inclined surface regions.

Abstract: This invention relates to a remotely optically powered fiber optic switch, e.g. in a fiber optic network, and a GRIN-rod (Graded-Refractive-Index-rod) lens with integrated planar mirror as a switching element, in particular suited for fiber optic switches. A distribution panel, in which the switching element, a wavelength-division demultiplexer, a light-into-current converter, and an actuator for the switching element are situated, is remotely optically powered from a station in the network. Part of this station is a laser diode which feeds a powering lightwave via a wavelength-division multiplexer into an optical fiber interconnecting the station with the distribution panel, which fiber can also be used for data transmission. The light-into-current converter receives the powering lightwave and generates an electric current for driving the actuator and moving the switching element.

Abstract: Automatic alignment of an optical waveguide to a ridge waveguide laser is accomplished by transferring the ridge structure of the laser to a substrate by etching a mirror groove. The transferred ridge structure serves as a base for the deposition of waveguide layers. The thickness of the waveguide layers are controlled during the deposition such that the waveguide core is laterally and vertically aligned to the lasing active layer of the laser structure.