Abstract: A wireless communication system uses relaying to enhance performance. Artificial frequency selectivity and spatial diversity are provided by introducing delay diversity. A transformed OFDM chunk is subjected to a 2D cyclic prefix by pre-appending to a representation of the chunk the last column of the representation and by copying a number of the last rows of the pre-appended chunk to the top of the representation thereby forming an augmented OFDM chunk.

Abstract: A point to multipoint device for use in a wireless network to provide wireless communication with a plurality of telecommunications units is described, for communication from the point to multipoint device to the telecommunications units, the point to multipoint device being operable to employ multiple sets of beams, at any point in time one set being used. The point to multipoint device comprises beam set generation logic for generating the multiple sets of beams arranged into one or more groups, each group comprising one beam from each set. Within each group the beams of that group are orthogonal with respect to each other, and each beam within each set is generated randomly with respect to other beams in that set. An interface is provided for receiving a synchronization signal issued to all point to multipoint devices in the wireless network.

Abstract: A wireless communication system with relaying to enhance performance provides artificial frequency selectivity and spatial diversity by introducing delay diversity. A OFDM chunk is subjected to a 2D cyclic prefix by pre-appending to a representation of the chunk the last column of the representation. The last row of the pre-appended chunk is copied to the top of the augmented chunk forming an augmented chunk.

Abstract: An antenna array in a radio node includes multiple antenna elements for transmitting a wider beam covering a majority of a sector cell that includes a common signal and a narrower beam covering only a part of the sector cell that includes a mobile user-specific signal. Transmitting circuitry is coupled to the antenna array, and processing circuitry is coupled to the transmitting circuitry. The processing circuitry ensures the user-specific signal and the common signal in a mixed beam embodiment are in-phase and time-aligned at the antenna array. In a steered beam embodiment, the processing circuitry ensures the user-specific signal and the common signal are time-aligned and have a controlled phase difference when received at mobile stations in the sector cell. In both embodiments, distortions in the common signal and the user-specific signal associated with their conversion from baseband frequency to radio frequency are also compensated.

Abstract: A point to multipoint device for use in a wireless network operates a sequence of variable duration communication channels, allocatable to telecommunications units. A training sequence indication and a repetition rate indication are stored indicating a training sequence and repetition rate for the training sequence in the sequence of communication channels associated with the point to multipoint device. An interface receives a synchronization signal issued to all point to multipoint devices in the wireless network, and uses it to determine a time for a first occurrence of the training sequence to occur. Communication channel control logic causes control data to be transmitted to the telecommunications units identifying the sequence of channels, the training sequence indication and the repetition rate. Beamforming logic determines beamforming weights used to produce a reception beam at an antenna array.

Abstract: A radio base station includes multiple antennas associated with a cell. Multiple mobile radios are selected to receive transmissions over a shared radio channel during a predetermined time interval. Information is transmitted over the shared radio channel to multiple mobile radios in the cell during the predetermined time interval using multiple antenna beams. As a result, interference from the transmission appears as white additive Gaussian noise in time and in space in the cell. A “flashlight effect” caused by a single beam transmission over the shared channel during a predetermined time interval that would normally detrimentally impact mobile channel quality detection is avoided. Other methods for avoiding the flashlight effect are described.

Abstract: A point to multipoint device for use in a wireless network to provide wireless communication with a plurality of telecommunications units is described, for communication from the point to multipoint device to the telecommunications units, the point to multipoint device being operable to employ multiple sets of beams, at any point in time one set being used. The point to multipoint device comprises beam set generation logic for generating the multiple sets of beams arranged into one or more groups, each group comprising one beam from each set. Within each group the beams of that group are orthogonal with respect to each other, and each beam within each set is generated randomly with respect to other beams in that set. An interface is provided for receiving a synchronisation signal issued to all point to multipoint devices in the wireless network.

Abstract: The present invention relates to wireless communication systems wherein relaying is used to enhance performance. According to the method and arrangement of the invention artificial frequency selectivity and spatial diversity is provided by introducing delay diversity. A OFDM chunk is subjected to a 2D cyclic prefix by pre-appending to a representation of the chunk the last column of the representation. The last rows of the pre-appended chunk is copied to the top of the augmented chunk forming an augmented chunk.

Abstract: A point to multipoint device for use in a wireless network to provide wireless communication with a plurality of telecommunications units is described. For communication from the telecommunications units to the point to multipoint device, the point to multipoint device is operable to define a sequence of variable duration communication channels, each communication channel being allocatable to one of the telecommunications units. The point to multipoint device has training sequence storage for storing a training sequence indication indicating a training sequence associated with the point to multipoint device. Repetition rate storage is also provided for storing a repetition rate at which the training sequence is to be repeated in the sequence of communication channels, the repetition rate being the same for all point to multipoint devices in the wireless network.

Abstract: In controlling a multi-beam antenna system for downlink wireless communication, beamforming and closed loop transmit diversity signaling are combined. Each beam signal is adjusted at the transmitter based on feedback from a wireless mobile communication station such that the signals received at the wireless mobile communication station can be coherently combined.

Abstract: A radio channel estimation technique is described for use in a OFDM-based radio communications system. A block of OFDM symbols is transmitted from multiple antennas over multiple sub-carrier frequencies. The block of OFDM symbols includes known pilot symbols as well as data symbols to be determined by a receiver. The pilot symbols are transmitted in a predetermined pattern at periodic times on periodic sub-carriers. A pilot channel estimate is determined for each pilot symbol in the received block of OFDM symbols. An N×M matrix of points corresponding to the received OFDM symbol block is formed. N is the number of sub-carriers and M is the number of OFDM symbols in the OFDM symbol block. The matrix is formed by inserting pilot channel estimates at predetermined positions in the N×M matrix according to the predetermined pilot pattern and inserting zeros in remaining positions in the N×M matrix.

Abstract: The invention is a switched beam beamforming method and apparatus for wireless communication receiving stations utilizing an array of antenna elements in which only a single beam is generated at any given instant and the beam is switched at a very high rate, e.g., faster than the data rate of the system. An algorithm for scheduling the beamforming sequence is disclosed that optimizes performance by optimizing the signal/interference-plus-noise ratio for a given set of conditions at any instant in time. In particular, spatial diversity offered by antenna arrays for direct sequence-code division multiple access communication systems is exploited by an intelligent switched beam antenna at radio frequency level. The design is optimized to yield conditional mean estimates of the communication channel during uplink transmission and compute minimum variance estimates of the communication channel by optimally combining the signals of the spatially distributed antennas at chip rate.

Abstract: An antenna array in a radio node includes multiple antenna elements for transmitting a wider beam covering a majority of a sector cell that includes a common signal and a narrower beam covering only a part of the sector cell that includes a mobile user-specific signal. Transmitting circuitry is coupled to the antenna array, and processing circuitry is coupled to the transmitting circuitry. The processing circuitry ensures the user-specific signal and the common signal in a mixed beam embodiment are in-phase and time-aligned at the antenna array. In a steered beam embodiment, the processing circuitry ensures the user-specific signal and the common signal are time-aligned and have a controlled phase difference when received at mobile stations in the sector cell. In both embodiments, distortions in the common signal and the user-specific signal associated with their conversion from baseband frequency to radio frequency are also compensated.

Abstract: A radio base station includes multiple antennas associated with a cell. Multiple mobile radios are selected to receive transmissions over a shared radio channel during a predetermined time interval. Information is transmitted over the shared radio channel to multiple mobile radios in the cell during the predetermined time interval using multiple antenna beams. As a result, interference from the transmission appears as white additive Gaussian noise in time and in space in the cell. A “flashlight effect” caused by a single beam transmission over the shared channel during a predetermined time interval that would normally detrimentally impact mobile channel quality detection is avoided. Other methods for avoiding the flashlight effect are described.

Abstract: In controlling a multi-beam antenna system for downlink wireless communication, beamforming and closed loop transmit diversity signaling are combined. Each beam signal is adjusted at the transmitter based on feedback from a wireless mobile communication station such that the signals received at the wireless mobile communication station can be coherently combined.

Abstract: A computer-implemented approach for reducing distortion in digital communications systems generally involves obtaining an optimal estimation of the original data using a Kalman filter with an increased length state to remove substantially all ISI in the time domain. The use of an increased length state in the Kalman filter provides a more accurate estimate of the transmitted data with relatively little additional computational cost. Subsequent equalization may also be performed in the frequency domain to correct any residual amplitude and phase distortion.