Abstract: A method for discovering a network among a plurality of mobile nodes, which includes: a first mobile node periodically transmitting a first signal including an invitation token including data relating to an identity of the node which transmits the token; a second mobile node detecting the first signal; transmitting a second signal including at least one acknowledgement of the invitation token; creating a radio bubble, the communications between the nodes of the radio bubble being coordinated by transmitting a speech token between the nodes; and creating an IP sub-network between the nodes of the radio bubble, each node including an IP address.

Abstract: A method for discovering a network among a plurality of mobile nodes, which includes: a first mobile node periodically transmitting a first signal including an invitation token including data relating to an identity of the node which transmits the token; a second mobile node detecting the first signal; transmitting a second signal including at least one acknowledgement of the invitation token; creating a radio bubble, the communications between the nodes of the radio bubble being coordinated by transmitting a speech token between the nodes; and creating an IP sub-network between the nodes of the radio bubble, each node including an IP address.

Abstract: A wireless transmitter includes a stream parser for generating a plurality of spatial streams from a digital signal and a space time block coder (STBC) for mapping each of the spatial streams to a plurality of space-time streams that each include data and a preamble for estimating a channel transfer function. The transmitter also includes a spatial mapper for spatially expanding each of the space-time streams by applying a spatial expansion matrix to data and to first training symbols used in the preamble to probe a channel experienced by the data and by applying an extension matrix to second training symbols used in the preamble to probe at least one additional dimension of the channel to enable use of beamforming to achieve range extension The spatial expansion matrix and the extension matrix form an overall matrix that has at least two orthogonal columns with different norms.

Abstract: A communication system comprises a set of user equipments which are arranged to simultaneously transmit a signal over an air interface to a base station. Each of the transmitted signals comprises a data stream encoded by a space time block code and transmitted on multiple antennas. Specifically, an Alamouti code may be used. The base station generates a received data stream for each of the set of user equipments by joint space time block code decoding of the signals from the set of user equipments. The invention may provide improved performance and increased capacity and may in particular provide efficient multi user operation for a system using space time block codes. The user equipments may be scheduled in response to cross interference metrics reflecting a cross interference between simultaneously transmitting user equipments.

Abstract: A Multiple In Multiple Out (MIMO) communication system comprises an air interface scheduler for allocating air interface resource to a plurality of user equipments transmitting to a MIMO receiver. A vector processor of the scheduler determines a receive equalizer vector for the MIMO receiver for each of a plurality of user equipments in response to a channel matrix for the user equipment. The vector processor may specifically apply singular value decomposition to the channel matrix to determine the receive equalizer vector. An orthogonality processor then determines orthogonality measures between receive equalizer vectors for different sets of user equipments. A selection processor selects a set of user equipments to be allocated a shared MIMO air interface resource in response to the orthogonality measures. By scheduling in response to orthogonality of receiver operations, a reduced interference and/or reduced receiver complexity can be achieved.

Abstract: An optical to radio frequency detector comprises an optical guide for receiving two optical signal components having frequencies that differ by an amount corresponding to a radio frequency, and a radio signal guide coupled with an interaction zone of the optical guide for propagating a radio signal from the interaction zone at the radio frequency. The material of the interaction zone presents a second-order non-linear optical polarization characteristic to the propagation of the optical signal components, and the radio signal guide is in travelling-wave coupling with the interaction zone. A radio signal output is coupled with the radio signal guide.

Abstract: An Orthogonal Frequency Division Multiplexing, OFDM, transmitter comprises a signalling data generator (113) which generates a set of data symbols indicative of physical layer characteristics of data transmissions from the OFDM transmitter (100). A first symbol generator (115) and second symbol generator (117) generates a first and second OFDM signalling symbol by allocating the set of data symbols to subcarriers. The allocation of the physical layer data symbols to subcarriers is different for the first OFDM signalling symbol and the second OFDM signalling symbol. A data packet generator (105) and transmitter (101) generate a data packet and transmit this to an OFDM receiver (300). The OFDM receiver (300) determines the physical layer data symbols by combining the data symbols of corresponding subcarriers of the first and second OFDM signalling symbols and uses the resulting information to decode the user data of the data packet.

Abstract: A wireless transmitter includes a stream parser for generating a plurality of spatial streams from a digital signal and a space time block coder (STBC) for mapping each of the spatial streams to a plurality of space-time streams that each include data and a preamble for estimating a channel transfer function. The transmitter also includes a spatial mapper for spatially expanding each of the space-time streams by applying a spatial expansion matrix to data and to first training symbols used in the preamble to probe a channel experienced by the data and by applying an extension matrix to second training symbols used in the preamble to probe at least one additional dimension of the channel to enable use of beamforming to achieve range extension The spatial expansion matrix and the extension matrix form an overall matrix that has at least two orthogonal columns with different norms.

Abstract: A Multiple In Multiple Out (MIMO) communication system comprises an air interface scheduler for allocating air interface resource to a plurality of user equipments transmitting to a MIMO receiver. A vector processor of the scheduler determines a receive equalizer vector for the MIMO receiver for each of a plurality of user equipments in response to a channel matrix for the user equipment. The vector processor may specifically apply singular value decomposition to the channel matrix to determine the receive equalizer vector. An orthogonality processor then determines orthogonality measures between receive equalizer vectors for different sets of user equipments. A selection processor selects a set of user equipments to be allocated a shared MIMO air interface resource in response to the orthogonality measures. By scheduling in response to orthogonality of receiver operations, a reduced interference and/or reduced receiver complexity can be achieved.

Abstract: A communication system comprises a set of user equipments which are arranged to simultaneously transmit a signal over an air interface to a base station. Each of the transmitted signals comprises a data stream encoded by a space time block code and transmitted on multiple antennas. Specifically, an Alamouti code may be used. The base station generates a received data stream for each of the set of user equipments by joint space time block code decoding of the signals from the set of user equipments. The invention may provide improved performance and increased capacity and may in particular provide efficient multi user operation for a system using space time block codes. The user equipments may be scheduled in response to cross interference metrics reflecting a cross interference between simultaneously transmitting user equipments.

Abstract: An Orthogonal Frequency Division Multiplexing, OFDM, transmitter comprises a signalling data generator (113) which generates a set of data symbols indicative of physical layer characteristics of data transmissions from the OFDM transmitter (100). A first symbol generator (115) and second symbol generator (117) generates a first and second OFDM signalling symbol by allocating the set of data symbols to subcarriers. The allocation of the physical layer data symbols to subcarriers is different for the first OFDM signalling symbol and the second OFDM signalling symbol. A data packet generator (105) and transmitter (101) generate a data packet and transmit this to an OFDM receiver (300). The OFDM receiver (300) determines the physical layer data symbols by combining the data symbols of corresponding subcarriers of the first and second OFDM signalling symbols and uses the resulting information to decode the user data of the data packet.

Abstract: A method for conversion of signals between analog and digital characterised by; applying a non-linear transfer function to an input signal, such that the relation between the quantisation levels of the converter and the input signal vary as a non-linear function of the magnitude of the input signal. The non-linear transfer function is related to the probability density function of the input signal so that larger quantisation bins of the converter correspond to less probable values of the input signal.

Abstract: A method is provided to compensate for environmental factors experienced by a wireless signal during transmission between a transmitter and a receiver. The method begins by receiving a wireless signal that includes a data frame having a preamble used to estimate a quantity (e.g., a channel transfer function) relating to signal quality. A portion of the preamble includes information specifying at least one parameter defining a format employed by the data frame. The selected portion of the preamble is decoded and a value for the quantity is estimated using the received preamble, including the decoded selected portion thereof. A signal is demodulated based at least in part on the estimated value of the quantity.

Abstract: A detector or a modulator for converting between optical and radio frequency signals comprising an optical guide (11 to 14) for propagating two optical signal components having frequencies that differ by an amount corresponding to a radio frequency and a microstrip radio signal guide (15, 16) for propagating a radio signal at the radio frequency, the microstrip radio signal guide being in travelling-wave coupling with an interaction one (14) of the optical guide comprising material in which interaction between the optical signal components and the radio signal occur. The microstrip radio signal guide element (15, 16) comprises an electrically conductive strip (15) juxtaposed with and extending along the interaction zone (14) on one side thereof and an electrically conductive ground plane (16) juxtaposed with and extending along the interaction zone (14) on an opposite side thereof.

Abstract: A method for analog to digital conversion (ADC) characterised by; applying a non-linear transfer function to an input signal, such that the relation between the quantisation levels of the converter and the input signal vary as a non-linear function of the magnitude of the input signal. The non-linear transfer function is related to an at least approximate measurement of probability density function ‘p(x)’ of said input signal so that larger quantisation bins of the converter correspond to less probable values of the input signal. The relation is iteratively updated by updating quantisation levels.

Abstract: An optical to radio frequency detector comprising an optical guide (11 to 14) for receiving two optical signal components having frequencies that differ by an amount corresponding to a radio frequency, and a radio signal guide (15, 16) coupled with an interaction zone (14) of the optical guide for propagating a radio signal from the interaction zone at the radio frequency. the interaction zone (14) of the optical guide comprises an interaction material presenting a second-order non-linear optical polarisation characteristic to the propagatio of the optical signal components, and the radio signal guide (15,16) is in travelling-wave coupling with the interaction zone. the interaction material includes electrically orientated diazobenzene.

Abstract: A detector or a modulator for converting between optical and radio frequency signals comprising an optical guide (11 to 14) for propagating two optical signal components having frequencies that differ by an amount corresponding to a radio frequency and a microstrip radio signal guide (15, 16) for propagating a radio signal at the radio frequency, the microstrip radio signal guide being in travelling-wave coupling with an interaction one (14) of the optical guide comprising material in which interaction between the optical signal components and the radio signal occur. The microstrip radio signal guide element (15, 16) comprises an electrically conductive strip (15) juxtaposed with and extending along the interaction zone (14) on one side thereof and an electrically conductive ground plane (16) juxtaposed with and extending along the interaction zone (14) on an opposite side thereof.

Abstract: The card (40) is a plate in the form of a bank card which is provided with a power source, a microcontroller (144), a personal data memory (254), an acquired data memory (256), and a data-in-transit memory (212). Each card possesses two coupling members, i.e. a transmitter and a receiver on each of its faces, together with two manual activators (42-52) adapted to put it into operation. An operation of interchanging data between a plurality of cards (40.1, . . . , 40.4) comprises an initial step of checking feasibility in which a down stage during which the personal data in each card is accumulated (arrows 41.1, 41.2, 41.3) in the data-in-transit memories (212) of the cards disposed there beneath, and the other stage being an up stage symmetrical to the preceding stage. The end of this second stage triggers a down procedure in which the acquired data memories (256) are loaded. The last card in the stack issues an audible signal (58) to indicate that the operation has finished successfully.