Abstract: Provided are methods and apparatuses to encode portions of user data with corresponding spreading sequences within a frame wherein the user data is associated with a single user.

Abstract: Precoding information prior to MIMO transmission is described, comprising determining a suitable preceding perturbation. The perturbation is determined by assembling a list of candidate perturbations in reduced lattice space, transforming these back into information lattice space and determining which candidate precoder perturbation is most suitable given a performance criterion.

Abstract: Channel estimation in a MIMO communications system comprises performing a decomposition of an initial channel matrix estimate associated with a first subcarrier of a plurality thereof defined in the channel to identify eigenvectors associated with that subcarrier of the received signal, and defining a first beamforming transformation to be applied to the received signal on the basis of the eigenvectors. Then, for each of the other subcarriers, an additional decomposition is performed in order to determine a further beamforming transformation for each of said one or more other subcarriers, wherein said additional decompositions are carried out incrementally such that information determined in one of said decompositions contributes to a later executed decomposition. Further described is a method of transmitting from a multiple antenna transmitter defining a plurality of subcarriers in space, and time or frequency, comprising the same iterative process.

Abstract: In a lattice-reduction-aided receiver based wireless communications system, outputs are determined on the basis of a received signal, the received signal being modulated onto a plurality of sub-carriers.

Abstract: In a lattice-reduction-aided receiver based wireless communications system, soft estimates of transmitted bit values are determined from a received signal by applying lattice reduction to the channel estimate and equalising the received signal in accordance with the reduced basis channel, and determining probabilities of transmitted bits having particular values by generating a set of candidate vectors in the reduced basis based on nearest candidate vectors, determining a corresponding transmitted symbol vector for each candidate vector and, on the basis of the received signal determining the probability of each transmitted bit value having been transmitted.

Abstract: A cellular communication system comprises a management function having a broadcast mode function; a plurality of wireless serving communication units operably coupled to the management function; and a plurality of wireless subscriber communication units receiving signals from respective wireless serving communication units in an uni-cast mode of operation on a frequency channel comprising a plurality of downlink transmission resources. The broadcast mode function applies a common cell identifier associated with broadcast transmissions from the plurality of wireless serving communication units thereby signalling to the plurality of wireless subscriber communication units that part or all of the transmission resource is to be configured or re-configured for broadcast mode of operation.

Abstract: A coherent or a noncoherent transmission mode is automatically selected for a transmission on the basis of an estimated Doppler frequency shift due to a motion of a mobile terminal. A coherent mode is selected if a pilot signal overhead is not excessive to uniquely characterize a Doppler frequency shift, as at lower carrier frequency times relative velocity products. A noncoherent mode is selected if a pilot signal overhead would be excessive to uniquely characterize a Doppler frequency shift at higher carrier frequency times relative velocity products. Both the coherent and noncoherent modes have respective advantages for their respective carrier frequency time relative velocity regimes.

Abstract: An Orthogonal Frequency Division Multiplex (OFDM) communication system comprises OFDM transmitters (103-109) and an OFDM receiver (101). The system comprises a subcarrier status data controller (200) for transmitting subcarrier status data to the OFDM receiver (101). The subcarrier status data indicates the active subcarriers of the OFDM transmitters (103-109). The OFDM receiver (101) comprises a receiver (201) which receives a signal comprising a desired signal component from a first OFDM transmitter (103) and interference from at least one interfering OFDM transmitter (105). The OFDM receiver (101) further comprises a subcarrier status processor (203) which receives the subcarrier status data and a channel estimator (205) which determines channel estimates for at least an air interface communication channel from the first OFDM transmitter (103) and an air interface communication channel from the interfering OFDM transmitter (105).

Abstract: A cellular communication system comprises a Multiple-In Multiple-Out, MIMO, transmitter (101) and receiver (103). The MIMO transmitter (101) comprises a message generator (303) for generating MIMO messages comprising selected training sequences and transceivers (305, 307, 309) transmitting the messages on a plurality of antennas (311, 313, 315). The training sequences are selected by a midamble selector (317) from a set of training sequences in response to an associated antenna on which the message is to be transmitted. The set of training sequences is associated with the cell of the MIMO transmitter and comprises disjoint subsets of training sequences for each of the plurality of antennas. The receiver (103) comprises a transmit antenna detector (419) which determines which antenna of the MIMO transmitter the message is transmitted from in response to the training sequence of the received message.

Abstract: Provided are methods and apparatuses to encode portions of user data with corresponding spreading sequences within a frame wherein the user data is associated with a single user.

Abstract: The present invention relates to demodulation of radio signals from a base station having collocated transmit antennas, and more particularly to signaling allocation information from a base station to a mobile terminal. The allocation information may include timeslot and code information of allocation to other mobile terminals. Some embodiments of the present invention facilitate a mobile terminal's ability to receive and demodulate a signal containing multiple interfering signals by communicating codes allocated to other mobile terminals.

Abstract: Allocation of multiple training sequences transmitted in a MIMO timeslot from multiple transmit antenna elements is provided. For example, a method of generating signals in a MIMO timeslot, the method comprising: selecting a first training sequence; preparing a first data payload; generating a first signal including the prepared first data payload and the first training sequence; transmitting the first signal in a MIMO timeslot from a first antenna of a network element; selecting a second training sequence, wherein the second training sequence is different from first training sequence; preparing a second data payload; generating a second signal including the prepared second data payload and the second training sequence; and transmitting the second signal in the MIMO timeslot from a second antenna of the network element.