Abstract: Codebook based communication of precoding data between two stations involves determining a ‘best fit’ precoding at a receiving station, on the basis of channel state measurements taken therein. The best fit precoding is compared with pre-agreed entries in a codebook, and an indicator is sent back to the terminal emitting the analysed signal. The determination is separated into two elements, one being sufficient for use with SU-MIMO, and another being provided, with a second codebook indicator, if MU-MIMO is to be employed. This second codebook indicator points to a codebook of eigenvector representations for the multi-user space in which the channel is persisting.

Abstract: The present disclosure concerns the harnessing of the effect of a relay to enhance the ability to avoid the effect of interference at mobile stations. This is achieved either by overlaying beamforming for an indirectly reached mobile station so that a relay passes on this beamforming to the mobile station concerned, and retaining orthogonality therewith, or by harnessing a base station and a relay station together so that their combined effect is to provide spatial multiplexing to two or more mobile stations.

Abstract: A data compression process is described, for compressing channel state information to be fed back to a transmitter. The process involves arranging the data as a matrix comprising a number of orthonormal vectors derived from a channel matrix, determining a singular value decomposition of a subset of the orthonormal matrix to generate matrices respectively of left and right singular vectors, the number of vectors in the subset being equal to the order of the vectors, and right multiplying the remainder orthonormal vectors not included in the singular value decomposition by a matrix product of the matrix of right singular vectors and the matrix of left singular vectors to generate a matrix of compressed data.

Abstract: A radio communication station in a radio communication system having a plurality of radio communication devices, derives a quantisation parameter and transmits the quantisation parameter to the radio communication devices for use in subsequent quantisation of a channel state metric. The radio communication devices receive the quantisation parameter, determine a channel state metric, quantise the determined channel state metric by applying quantisation ranges indicated by the quantisation parameter, determine a data value indicative of the quantised channel state metric, and transmit a signal conveying the determined data value as a random access transmission.

Abstract: The present invention relates to a method for transmission of control information from a primary station to at least one secondary station, comprising the step of transmitting with a first set of control information parameters control information corresponding to data transmission with a first set of data parameters and transmitting with a second set of control information parameters control information corresponding to data transmission with a second set of data parameters, wherein at least one control information parameter has a difference in value between the two sets of control information parameters, said difference in value having a dependency on the difference between the value of a data parameter in the first set of data parameters and the value of the data parameter in the second set of data parameters, said data parameter being a different parameter from the at least one control information parameter.

Abstract: The present invention relates to a method for encoding a vector for transmission from a transmitter to a receiver, comprising a step of selecting a first vector in a predefined M-dimensional vector codebook, and at least one refinement step wherein an error vector between the random vector and the first vector is quantised by means of selecting a further vector from a further vector codebook with dimensionality reduced by one relative to the previous step, wherein the M-dimensional vector codebook and the further predefined vector codebook are known to both the transmitter and receiver.

Abstract: The present invention relates to a method for communicating from a primary station with an array of transmit antennas to a secondary station on a downlink channel, said method comprising steps of, at the primary station, (a) configuring the downlink channel, step (a) being subdivided into steps of: (a2) computing a precoding to be applied during a corresponding transmission from the primary station to the secondary station for each of an array of transmit antennas; (a3) applying a reversible transform N to the precoding, thus ascertaining a set of precoding coefficients substantially representative of the precoding in a transform domain; (a4) computing a set of parameters comprising at least one parameter, said parameter being substantially representative of the coefficients obtained at step (a3); (a5) signaling the set of parameters to the secondary station; (b) transmitting data to the secondary station substantially according to the precoding computed at step (a2).

Abstract: The present invention relates to a method for communicating in a network having a primary station and a plurality of secondary stations, said method comprising a step of, at the primary station, (a) configuring at least one downlink channel from the base station to a first secondary station, step (a) comprising (a1) signalling a first set of at least one parameter indicative of precoding applied to a first transmission from the base station to the first secondary station; (a2) signalling a second set of at least one parameter indicative of precoding applied to a second transmission from the base station to at least one second secondary station, wherein said step (a2) is carried out so that the second set of parameters contains less information than the first set of parameters.

Abstract: Processing data presented in the form of a vector representation involves representing direction of the vector with incremental accuracy by using a set of vector codebooks of decreasing dimensions per accuracy increment.

Abstract: A QAM receiver for constellations having at least 16 symbols converts its received QAM signal into outputs including indications of the received symbols. A channel frequency response estimator responsive to outputs of the converter derives indications of estimates of effects of a link to the receiver on the phase and amplitude of the received signals. A processor responsive to outputs of the converter and the estimator (1) equalises the phases of the converter outputs, (2) scales the amplitude estimates by amounts determined by the amplitude associated with the separation of boundaries between symbols in the constellation, and (3) combines the phase equalised converter outputs and the scaled amplitude estimates to derive likely bit values of the received symbols.

Abstract: Data is transmitted from a radio communication device (100) by selecting a signal dependent on data to be transmitted, transmitting to a radio communication station (200) the selected signal as a random access transmission, deriving an identifier dependent on the data, and employing the identifier to identify a subsequently received signal intended for the radio communication device (100). The data is received at a radio communication station (200) by receiving the random access signal which is indicative of the data to be received, determining the data indicated by the random access signal, deriving an identifier dependent on the determined data, and including the identifier in a subsequent transmission from the radio communication station (200) to identify the intended recipient of the subsequent transmission.

Abstract: The present invention relates to a control method for a communication network that has a transmitter with an array of transmit antennas and that has at least one receiver communicating with the transmitter. The receiver performs a channel measurement for a receive antenna of the receiver using a signal transmitted from the transmitter to the receiver. The receiver further determines channel coefficients for each of an array of transmit antennas at the transmitter from an output of the channel measurement, and then applies a linear, reversible and orthogonal transform to the channel coefficients, thus ascertaining channel component coefficients indicative of the individual weight of respective channel components in a transform domain. The receiver then selects one or more channel components in the transform domain and communicates to the transmitter a control signal indicative of one or more preferred channel components or a magnitude of one or more channel component coefficients, or both, in quantized form.

Abstract: A communication device (1) for communicating in a multiple channel communication system comprises means (9) for calculating an effective noise level of one of the channels of the system by applying an expectation operator to an estimated noise level affecting the channel based on time varying characteristics of the estimated noise level. The calculation of the effective noise level may also be based on an estimated path loss. The calculation of the effective noise level may also be based on an initial power level allocated to the respective channel. The effective noise level calculated for each channel may be employed in calculating power levels to be allocated to the respective channels.

Abstract: A Multiple Input Multiple Output (MIMO) communication system 1 has a transmitter for transmitting signals over a MIMO Broadcast Channel (MIMO-BC) 6. Data for communication to respective receivers 41, 4K-1, 4K is encoded by encoding stages 101, . . . , 10K-1, 10K in a selected order by selecting codewords c1, . . . cK-1, cK from codebooks C1, . . . CK-1, CK of a nested lattice code. Dither adders 111, . . . , 11K-1, 11K are arranged to add a respective dither d1 . . . , dK-1, dk to the selected codewords c1, . . . cK-1, cK. Quantising stages 121, . . . , 12K-1, 12K each perform respective quantising operations mod?S,1, . . . , mod?S,K-1, mod?S,K using the shaping lattice ?S of the nested lattice code. Quantised signals u1, . . . , uK-1, uK of data encoded earlier in the selected order are output to feedbackward filter stages 141, . . . , 14K-1 for filtering the codewords c1, . . . cK-1, cK of data encoded later in the selected order before they are quantised by the quantising stages 121, . . .

Abstract: In an OFDM system with modulation and coding adaptation, the carriers are allotted a respective plurality of transmission modes characterised each by a specific combination of a modulation format and a coding scheme and consequently by a specific combination of values of bit rate and power. To allocate to each carrier, for a given OFDM symbol to be transmitted, an optimum value of bit rate and power resulting in the maximum bit rate for a given power or in a minimum power for a given bit rate, all carriers are initially allotted the mode characterised by the highest bit rate or power. If the constraints on the power (or respectively the bit rate) are not met, an iterative mode reduction is performed, the mode reduction at each iteration step being performed on the carrier for which said transition has a minimum cost.

Abstract: A QAM receiver for constellations having at least 16 symbols converts its received QAM signal into outputs including indications of the received symbols. A channel frequency response estimator responsive to outputs of the converter derives indications of estimates of effects of a link to the receiver on the phase and amplitude of the received signals. A processor responsive to outputs of the converter and the estimator (1) equalises the phases of the converter outputs, (2) scales the amplitude estimates by amounts determined by the amplitude associated with the separation of boundaries between symbols in the constellation, and (3) combines the phase equalised converter outputs and the scaled amplitude estimates to derive likely bit values of the received symbols.