Abstract: A MMSE equaliser taking into account delays in the reception of signals from plural users. Time delays in reception of signals from plural users may be known or can be measured or estimated and can be used to for the basis for the operation of the equaliser. A low computational complexity version of the equaliser and a regularized equalizer with further reduced complexity for asynchronous reception are also disclosed.

Abstract: A method of relaying a signal in a wireless communications network comprising a plurality of wireless devices, the method being performed by at least one of said wireless devices to relay a signal in a communication path between one of said plurality of wireless devices and another one of said wireless devices, wherein said at least one of said wireless devices comprises a power amplifier for amplifying said signal, the method comprising receiving a signal from said one of said plurality of wireless devices, determining a peak-to-average power ratio of said received signal under a plurality of predetermined relay modes, determining a back-off value associated with said power amplifier, selecting a mode of relaying said signal from said plurality of predetermined relay modes based on said determined peak-to-average power ratio and said determined back-off value, and transmitting said signal to said another one of said plurality of wireless devices using said selected mode.

Abstract: A block of information is processed before transmission thereof in a block transmission based communication. This comprises inserting a cyclic prefix and a cyclic suffix into the block of information before applying a time reversal based prefilter prior to transmission to the data after cyclic prefix and cyclic suffix insertion, the prefilter being configured on the basis of knowledge of the condition of the channel over which communication is to be effected. Then, at the receiver, a removal operation is operable to remove the effect of cyclic prefix and suffix insertion, leaving a circulant shifted version of the original block. This can be decoded using a diagonal matrix containing frequency domain channel coefficients on its diagonal entries after FFT. For systems with more than two transmit antennas, this facilities the use of full rate OSTBC, regardless of whether real or complex signaling is transmitted.

Abstract: MIMO UWB Communications apparatus is configured to send out a channel estimation sequence comprising a plurality of sequentially transmitted symbols in accordance with a first band hopping sequence, sent from one antenna of the apparatus, while another antenna is transmitting another sequence of channel estimation symbols in accordance with another, complementary band hopping sequence. A legacy device will be capable of synchronising with the channel estimation symbols sent in accordance with the first band hopping sequence, while a MIMO receiver will be able to determine channel estimates for all MIMO channels on the basis of the combined channel estimation transmissions.

Abstract: A method of relaying a signal in a wireless communications network comprising a plurality of wireless devices, the method being performed by at least one of said wireless devices to relay a signal in a communication path between one of said plurality of wireless devices and another one of said wireless devices, the method comprising receiving a signal from said one of said plurality of wireless devices, determining channel statistical information relating to a part or the whole of said wireless communications network, selecting a mode of relaying said signal from a plurality of predetermined relay modes based on said determined channel statistical information, such that the outage probability for said communication path satisfy a predetermined condition, and transmitting said signal to said another one of said plurality of wireless devices using said selected mode.

Abstract: According to one embodiment there is provided a wireless communication device comprising a plurality of antennas and operable to transmit data on a plurality of subcarriers from one or more of said plurality of antennas over a communication channel, the device comprising a receiver configured to receive signals via each of said plurality of antennas, a processor configured to determine the number of subcarriers that can be allocated to one or more of said plurality of antennas for data transmission on the basis of received signal metrics associated with said received signals, and an antenna selector configured to select one or more of said plurality of antennas for transmitting data on said plurality of subcarriers based on said determination.

Abstract: Allocation of subcarriers of a wireless communications channel to antennas for transmission of said subcarriers from a multi-antenna transmitter, comprises selecting, for each subcarrier, the antenna with the most effective transmission performance against a predetermined performance criterion; and determining if subcarriers are evenly distributed amongst said antennas. If even distribution does not arise, then a reallocation sequence is performed. This comprises identifying, for an antenna having excessive subcarriers allocated thereto, the subcarriers allocated thereto and reallocating one of said subcarriers as required, said reallocated subcarrier being selected for reallocation on the basis of its impact on transmission performance.

Abstract: In an apparatus and method for generating a SC-FDMA signal having a sequence of symbols, a signal is generated by spreading blocks of symbols using a spreading code, then applying an inverse discrete Fourier transform (IDFT) to the symbols, followed by rotating the phase of each symbol, and applying a guard interval in the form of a cyclic prefix (CP), such that the spreading code is selected from sequences having a DFT matrix and Hadamard-Walsh sequence, and whereby the difference between the amounts for rotating the phase of adjacent symbols is constant. The spreading may be changed so as to change the data rate for each transmitter.

Abstract: A method and device for managing the use of antennas in a multiple antenna wireless transmission system for OFDM signals. The method includes defining a utility function which comprises a performance metric for transmission. Combinations of antenna and OFDM subcarriers are selected to optimize the utility function under two constraints. The first constraint is that the combinations of antenna and subcarrier include only one antenna for each subcarrier, the second constraint is that the combinations include the same number of subcarriers for each antenna.

Abstract: MIMO UWB Communications apparatus is configured to send out a channel estimation sequence comprising a plurality of sequentially transmitted symbols in accordance with a first band hopping sequence, sent from one antenna of the apparatus, while another antenna is transmitting another sequence of channel estimation symbols in accordance with another, complementary band hopping sequence. A legacy device will be capable of synchronising with the channel estimation symbols sent in accordance with the first band hopping sequence, while a MIMO receiver will be able to determine channel estimates for all MIMO channels on the basis of the combined channel estimation transmissions.

Abstract: According to one embodiment, antenna allocation or selection in a multi-antenna wireless communications device can be performed at a receiver or an emitter of a wireless communications signal. Selection takes place on the basis of antenna and frequency. Antenna selection in a disclosed embodiment involves a combination of bulk and per tone antenna selection.

Abstract: A MMSE equaliser taking into account delays in the reception of signals from plural users. Time delays in reception of signals from plural users may be known or can be measured or estimated and can be used to for the basis for the operation of the equaliser. A low computational complexity version of the equaliser and a regularized equalizer with further reduced complexity for asynchronous reception are also disclosed.

Abstract: A block of information is processed before transmission thereof in a block transmission based communication. This comprises inserting a cyclic prefix and a cyclic suffix into the block of information before applying a time reversal based prefilter prior to transmission to the data after cyclic prefix and cyclic suffix insertion, the prefilter being configured on the basis of knowledge of the condition of the channel over which communication is to be effected. Then, at the receiver, a removal operation is operable to remove the effect of cyclic prefix and suffix insertion, leaving a circulant shifted version of the original block. This can be decoded using a diagonal matrix containing frequency domain channel coefficients on its diagonal entries after FFT. For systems with more than two transmit antennas, this facilities the use of full rate OSTBC, regardless of whether real or complex signalling is transmitted.

Abstract: Allocation of subcarriers of a wireless communications channel to antennas for transmission of said subcarriers from a multi-antenna transmitter, comprises selecting, for each subcarrier, the antenna with the most effective transmission performance against a predetermined performance criterion; and determining if subcarriers are evenly distributed amongst said antennas. If even distribution does not arise, then a reallocation sequence is performed. This comprises identifying, for an antenna having excessive subcarriers allocated thereto, the subcarriers allocated thereto and reallocating one of said subcarriers as required, said reallocated subcarrier being selected for reallocation on the basis of its impact on transmission performance.

Abstract: The invention provides a method and device for managing the use of antennas in a multiple antenna wireless transmission system for OFDM signals. The method includes defining a utility function which comprises a performance metric for transmission. Combinations of antenna and OFDM subcarriers are selected to optimise the utility function under two constraints. The first constraint is that the combinations of antenna and subcarrier include only one antenna for each subcarrier, the second constraint is that the combinations include the same number of subcarriers for each antenna.

Abstract: A method of shaping signals intended for transmission via at least one antenna, each signal having a respective frequency spectrum and being for transmission via a respective antenna, comprises selecting at least one interference-reducing signal, each interference-reducing signal being such as to modify the signal frequency spectrum for the antenna or a respective one of the antennas to include a respective frequency notch at an interference band, and modifying the frequency spectra with the selected interference-reducing signal or signals, wherein the selection is subject to a constraint on at least one characteristic of the spectra as modified

Abstract: The present invention relates to a method of generating a signal for transmission over a channel subject to transmission conditions. A corresponding signal and a method of receiving a signal over a channel subject to transmission conditions are also disclosed. The invention further relates to a transmitter and a receiver.

Abstract: MIMO UWB Communications apparatus is configured to send out a channel estimation sequence comprising a plurality of sequentially transmitted symbols in accordance with a first band hopping sequence, sent from one antenna of the apparatus, while another antenna is transmitting another sequence of channel estimation symbols in accordance with another, complementary band hopping sequence. A legacy device will be capable of synchronising with the channel estimation symbols sent in accordance with the first band hopping sequence, while a MIMO receiver will be able to determine channel estimates for all MIMO channels on the basis of the combined channel estimation transmissions.

Abstract: A wireless MIMO communications network establishes channel estimation by means of a channel estimation sequence utilising band hopping in a conventional manner from a first antenna. This can then be detected by legacy SISO devices. A further channel estimation sequence is concurrently transmitted from one or more further antennas, the further channel estimation sequence using a band hopping sequence complementary with the aforementioned band hopping sequence so as to avoid collision therewith. This latter channel estimation sequence can thus be detected by cooperating MIMO receiving equipment to provide opportunities for channel estimation.

Abstract: A signal transmission system shapes the spectrum of a signal in a block transmission system by applying an envelope function, the shaping means comprising: means for optimising the envelope function under one or more constraints selected from a set of predetermined constraints; and means for applying the optimised envelope function to the signal, wherein the means for optimising the envelope function is operable to employ a quasi-Newton optimisation of reduced complexity in comparison with the classical Newton optimisation technique, for reduced computation in real time.