Abstract: Techniques for monitoring and predicting environmental operating conditions in a data center are provided. In one aspect, a method for real-time, three-dimensional analysis of environmental operating conditions in a data center includes the following steps. High spatial resolution three-dimensional measurements of one or more environmental variables in the data center made at a time t1 are obtained. Real-time measurements of the environmental variables in the data center made at a time t2, wherein t2 is later in time than t1, are obtained. The high spatial resolution three-dimensional measurements are combined with the real-time measurements to derive a model for the environmental variables in the data center at the time t2. The model is used to predict three-dimensional distributions of the environmental variables in the data center at the time t2. A base model can be created and used to derive the model for the data center at the time t2.

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 relates to a method and system for displaying a video signal in dependence on a user interaction. The system comprises a display for receiving the video signal, at least one transmitter for transmitting location signals, and at least three transceivers for receiving the location signals from the transmitter and for transmitting modified location signals. The geometric locations of the at least three transceivers are known to a computing device. The computing device is then able to derive a transmit location of the location signals based on the received modified location signals, wherein the computing device is adapted to modify the content of the video signal in response to the derived transmit location in dependence on the user interaction.

Abstract: Techniques for monitoring and predicting environmental operating conditions in a data center are provided. In one aspect, a method for real-time, three-dimensional analysis of environmental operating conditions in a data center includes the following steps. High spatial resolution three-dimensional measurements of one or more environmental variables in the data center made at a time t1 are obtained. Real-time measurements of the environmental variables in the data center made at a time t2, wherein t2 is later in time than t1, are obtained. The high spatial resolution three-dimensional measurements are combined with the real-time measurements to derive a model for the environmental variables in the data center at the time t2. The model is used to predict three-dimensional distributions of the environmental variables in the data center at the time t2. A base model can be created and used to derive the model for the data center at the time t2.

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: A robust method and system for communicating via ultra-wideband (UWB) radio transmission signals over multi-path channels with a very broad range of delay spread. The system includes an optimized non-coherent receiver structure of low complexity and potentially very low power consumption, while offering robust error rate performance for a wide variety of UWB multi-path channel. Use of the proposed transmission signals, referred to as combined PAM-PPM (pulse amplitude modulation-pulse position modulation) signals, together with the disclosed non-coherent receiver method and apparatus are applicable in any UWB communication, identification, sensor or localization system and network, where battery power consumption must be minimized without undue system performance degradation.

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: 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 present invention provides methods and systems for displaying a video signal depending upon a user interaction. An example system includes a display for receiving the video signal, at least one transmitter for transmitting location signals, and at least three transceivers for receiving the location signals from the transmitter and for transmitting modified location signals. The geometric locations of the at least three transceivers are known to a computing device. The computing device is then able to derive a transmit location of the location signals based on the received modified location signals, wherein the computing device is adapted to modify the content of the video signal in response to the derived transmit location depending upon the user interaction.

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 relates to a method and system for displaying a video signal in dependence on a user interaction. The system comprises a display for receiving the video signal, at least one transmitter for transmitting location signals, and at least three transceivers for receiving the location signals from the transmitter and for transmitting modified location signals. The geometric locations of the at least three transceivers are known to a computing device. The computing device is then able to derive a transmit location of the location signals based on the received modified location signals, wherein the computing device is adapted to modify the content of the video signal in response to the derived transmit location in dependence on the user interaction.

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, method, and system for determining a time of arrival (TOA) and time differences of arrival (TDOA) of a transmitted signal {S} receivable at different locations of known spatial coordinates. The system comprises a first transmitter 10 with a respective antenna feed point positioned at an a priori unknown location P and emitting a first signal {S}. The system includes furthermore a set of transceivers or transponder units 20, 30 comprising first receivers 22, 32 for receiving first signals {S} by means of respective antennas with feed points located at known locations Ln. Such system also comprises second transmitters 26, 36 emitting respective derived second signals {{tilde over (S)}n} after known and scheduled respective time intervals &dgr;n as measurable between the feed points of said respective first receiving antennas located at known locations Ln and respective second transmitting antenna located at locations L′n.

Abstract: Method for wireless optical communication between a transmitting station and a receiving station, whereby the transmitting station provides a Request-to-Send (RTS) frame to the receiving station to announce the transmission of a data frame, the receiving station provides a Clear-to-Send (CTS) frame to the transmitting station in case of correct reception of the RTS frame, and the transmitting station subsequently sends the data frame to the receiving station. The RTS frame comprises Preamble (PA), Synchronization (SYNC), and Robust Header (RH) fields. The RTS frame further comprises a Source Address/Destination Address field (SA/DA) and a Cyclic Redundancy Check field (CRC). Adjusting the power level of the RTS frame to be different from the nominal transmission power level at which the data frame is sent, and by variable repetition coding within the Robust Header (RH) field of the RTS frame, allows a larger dynamic range of link quality estimation and improved collision avoidance properties.

Abstract: In a maximum likelihood sequence detector for symbol sequences which were equalized in a PR4 equalizer, noise prediction means (35) are provided including infinite impulse response (IIR) filtering, which have noise-whitening capabilities and are imbedded into the maximum likelihood detection process. The resulting INPML detector (10) can be implemented in digital or analog circuit technology. In addition, a DC-notch filter (44a) and a stochastic gradient procedure can be provided for DC offset compensation and for MR head or signal asymmetry compensation.

Abstract: The present invention provides an apparatus, method, and system for determining a time of arrival (TOA) and time differences of arrival (TDOA) of a transmitted signal {S} receivable at different locations of known spatial coordinates. The system comprises a first transmitter 10 with a respective antenna feed point positioned at an a priori unknown location P and emitting a first signal {S}. The system includes furthermore a set of transceivers or transponder units 20, 30 comprising first receivers 22, 32 for receiving first signals {S} by means of respective antennas with feed points located at known locations Ln. Such system also comprises second transmitters 26, 36 emitting respective derived second signals {{tilde over (S)}n} after known and scheduled respective time intervals &dgr;n as measurable between the feed points of said respective first receiving antennas located at known locations Ln and respective second transmitting antenna located at locations L′n.

Abstract: Disclosed is an optical communication system enabling communication between several co-existing transmitting and receiving stations. In order to allow communication between the co-existing stations, a robust physical layer header (RPLH; 50) is employed which can be understood by all participating stations. This robust header (50) at least comprises a preamble (52) consisting of frames forming a periodic sequence of pulses, the number of slots per frame and the frame content being known to all participating stations. The preamble (52) serves for relative synchronization and carrier detection of the receiving stations. The robust header (50) further comprises a unique synchronization word (53) used for absolute synchronization of the receiving stations. This synchronization word (53) is followed by a control field (59) of fixed length and known structure. By means of this control field (59) the receiving stations are informed which modulation method will be used for the transmission of data.

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.