Abstract: A micro-system, for example a micro-sensor, includes a resonator 10 with vibrating element(s) 11 receiving an excitation signal E of a loop 20 for automatic gain control, as a function of an amplitude setpoint (C) and providing as output a signal y(t) defined by a peak amplitude having a nominal value A0 dependent on the said setpoint and a resonant frequency. The micro-sensor integrates a circuit for measuring a quality factor of the resonator based on a measurement of an attenuation of the output signal during a momentary phase of cutoff of the excitation signal E applied to the resonator. This circuit for measuring the quality factor is configured so as to activate the excitation signal cutoff phase, for a duration of cutoff Td such that at the end of the cutoff phase, the peak amplitude of the output signal is attenuated by factor to the nominal peak amplitude A0 at the start of the cutoff phase, by a factor k with 1<k?2.

Abstract: A micro-system, for example a micro-sensor, comprises a resonator 10 with vibrating element(s) 11 receiving an excitation signal E of a loop 20 for automatic gain control, as a function of an amplitude setpoint (C) and providing as output a signal y(t) defined by a peak amplitude having a nominal value A0 dependent on the said setpoint and a resonant frequency. The micro-sensor integrates a circuit for measuring a quality factor of the resonator based on a measurement of an attenuation of the output signal during a momentary phase of cutoff of the excitation signal E applied to the resonator. This circuit for measuring the quality factor is configured so as to activate the excitation signal cutoff phase, for a duration of cutoff Td such that at the end of the cutoff phase, the peak amplitude of the output signal is attenuated by factor to the nominal peak amplitude A0 at the start of the cutoff phase, by a factor k with 1<k?2.

Abstract: A transmitter comprises a block generator (109) which divides a data symbol stream into data symbol blocks. A divide processor (111) divides each block into a first set of data symbols stored in a first set buffer (113) and a second set of data symbols stored in a second set buffer (115). A space time block encoder (117) codes the first set in accordance with a space time block code to generate a coded set of data symbols. A parallel processor (119) then creates a plurality of parallel data streams from the coded set and the second set. Each of the parallel data streams is allocated to one of a plurality of antennas (129-135). A plurality of parallel stream transmitters (121-127) transmits the parallel data streams in parallel in a communication channel from the plurality of transmit antennas (129-135).

Abstract: A method for cooperative relaying within multi hop wireless communication systems includes a base station, in an attempt to decode a data packet, combining hard sliced channel bits and Logarithmic Likelihood Ratio (LLR) quality information received from relay stations who had also received the data packet with stored information about the data packet.

Abstract: A transmitter comprises a block generator (109) which divides a data symbol stream into data symbol blocks. A divide processor (111) divides each block into a first set of data symbols stored in a first set buffer (113) and a second set of data symbols stored in a second set buffer (115). A space time block encoder (117) codes the first set in accordance with a space time block code to generate a coded set of data symbols. A parallel processor (119) then creates a plurality of parallel data streams from the coded set and the second set. Each of the parallel data streams is allocated to one of a plurality of antennas (129-135). A plurality of parallel stream transmitters (121-127) transmits the parallel data streams in parallel in a communication channel from the plurality of transmit antennas (129-135).

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 cooperative relaying within multi hop wireless communication systems includes a base station, in an attempt to decode a data packet, combining hard sliced channel bits and Logarithmic Likelihood Ratio (LLR) quality information received from relay stations who had also received the data packet with stored information about the data packet.

Abstract: A method and system for link adaptation between a wireless multi-carrier access point (102) and a wireless multi-carrier communication device (104) is described. The wireless multi-carrier access point obtains a set of available LEP methods from the wireless multi-carrier communication device. The wireless multi-carrier access point selects an LEP method from the set of available LEP methods, based on at least one link parameter. The wireless multi-carrier access point then communicates the LEP method selected, to the wireless multi-carrier communication device. The selected LEP method is used during the transmission of information between the wireless multi-carrier access point and the wireless multi-carrier communication device.

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 receiver for an orthogonal frequency division multiplex radio signal in which a carrier frequency is modulated by sub-carrier signals (S1) coded with data. Analogue signal processing means (3 to 12) produces base-band analogue signals (I-Rx, Q-Rx) in phase quadrature and analogue-to-digital converters (13, 14) convert the analogue signals to phase quadrature digital signals (xI(n), xq(n)). The digital signal processor includes the OFDM demodulator (15) and mismatch compensation (17, 18). The mismatch compensation (17, 18) combines each of the reproduced sub-carrier signals (RI) with a limited number of the reproduced sub-carrier signals (RI-Rk) according to respective frequency offset coefficient (I, k) that is a function of an estimated value of the offset (fc) of the reference frequency relative to the carrier frequency.

Abstract: A method and system for link adaptation between a wireless multi-carrier access point (102) and a wireless multi-carrier communication device (104) is described. The wireless multi-carrier access point obtains a set of available LEP methods from the wireless multi-carrier communication device. The wireless multi-carrier access point selects an LEP method from the set of available LEP methods, based on at least one link parameter. The wireless multi-carrier access point then communicates the LEP method selected, to the wireless multi-carrier communication device. The selected LEP method is used during the transmission of information between the wireless multi-carrier access point and the wireless multi-carrier communication device.

Abstract: A wireless communication unit (4160) comprises a processor (508) having a power-aware link adaptation function (540) for selecting an operational mode of the wireless communication unit (460) to transmit at least one data packet, the wireless communication unit (460) characterised in that the processor (508) is configured to perform, or is operably coupled to, a communication medium monitoring function that monitors an occupancy of a communication medium that comprises a plurality of communication links and, in response to a determination of i-he occupancy of the communication medium, the processor (508) performs link adaptation for at least one data packet transmission of the wireless communication unit (460). In this manner, in the provision of a power-aware link adaptation concept together with a communication medium occupancy monitoring function one or more of several links sharing the same communication medium can be selected to minimise power consumption within the wireless communication unit.

Abstract: A receiver for an orthogonal frequency division multiplex radio signal in which a carrier frequency is modulated by sub-carrier signals (S1) coded with data. Analogue signal processing means (3 to 12) produces base-band analogue signals (I-Rx, Q-Rx) in phase quadrature and analogue-to-digital converters (13, 14) convert the analogue signals to phase quadrature digital signals (x1(n), xq(n)). The digital signal processor includes the OFDM demodulator (15) and mismatch compensation (17, 18). The mismatch compensation (17, 18) combines each of the reproduced sub-carrier signals (R1) with a limited number of the reproduced sub-carrier signals (R1-Rk) according to respective frequency offset coefficient (1, k) that is a function of an estimated value of the offset (fc) of the reference frequency relative to the carrier frequency.

Abstract: An apparatus for improving signal mismatch compensation between first and second RF signals comprises: at least one switch which applies a first RF signal, present on a first pathway, and a second RF signal, present on a second pathway, to respective first and second frequency mixers, during a first time period; the mixers provide a first pair of mixed first and second RF signals. Means for reversing the at least one switch, during a subsequent time period is provided so that the first RF signal is applied to the second mixer, via the second pathway, and the second RF signal is applied to the first mixer, via the first pathway. The mixers thereby provide a second pair of mixed first and second RF signals. Monitoring monitors respective first and second pairs of mixed RF signals during an interval.

Abstract: A method of communication between two or more terminals (6, 7) with detection of interference, especially in a HiperLAN/2 system, comprising transmitting data between the terminals (6, 7) in electromagnetic signals of at least a first duration, the electromagnetic signals comprising one or more carrier frequencies within one or more ranges (1, 2) for which extra-system interference, especially with radar signals, is possible, at least one of the terminals (6, 7) being responsive to received signal strengths corresponding to intra-system interference (4, 17, 18). Detection of extra-system interference (5, 16) comprises at least one of the terminals (6, 7) responding selectively to received signal strengths that exceed a threshold level (19) for a second duration that is shorter than the first duration.

Abstract: Apparatus for estimating carrier and clock frequency offsets in OFDM systems employs a maximun likelihood estimator operation on the demodulated signals. The invention has the benefit of low complexity and obviates the need for any requirement for a dedicated training channel.