Abstract: Radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based cellular wireless radio transmission system, wherein radio access equipment of the system connects to multiple geographically spread radio antennas of a Distributed Antenna System, DAS, for transmitting to and receiving radio signals from user equipment. Transmit timings for radio transmission between the user equipment and the antennas of the DAS are established. The radio transmission is scheduled based on the established transmit timings.

Abstract: The present invention relates to a node (1) in a wireless communication network, where the node (1) is arranged to receive at least two signals (y1(n), y2(n)) which correspond to at least two transmitted uncorrelated signal streams (x1(n), X2(n)) which have been transmitted to the node via a channel. The channel (2) is signals represented by means of a channel matrix (H(q?1)). The node (1) comprises a controllable filter structure (3) that is arranged to diagonalize the channel matrix (H(q?1)) such that a channel matrix estimation (?(q?1)) may be obtained. The present invention also relates to a corresponding method.

Abstract: The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate.

Abstract: The present invention relates to a multi-stream communication system comprising a transmitting node provided with a polyphase antenna and a receiving node provided with an antenna arrangement configured to receive multiple data streams. The polyphase antenna has at least one group of multiple antenna elements, each group having N antenna elements. The transmitting node is also provided with at least one radio chain and a switch for each radio chain arranged to cyclically connect each radio chain to the antenna elements in one of the groups. The switch is configured to operate with a switching frequency fsw. The transmitting node is further configured to transmit M weighted symbols of an uncorrelated signal from each antenna element in each group, the M weighted symbols being less than or equal to N, and the receiving node is further configured to convert the received N data streams into each respective uncorrelated signal.

Abstract: For compensating carrier frequency generation in communication equipment for radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based wireless radio communication system, in which reference signals known communication equipment are transmitted in a regular time repetitive manner, carrier frequency generation is compensated (63) by a calculated carrier frequency offset estimate. The carrier frequency offset estimate in the communication equipment is calculated from coarse (61) and fine carrier frequency offset estimates (62). The coarse carrier frequency offset estimate (61) is calculated in the frequency domain from reference symbols of a reference signal received (60) at the communication equipment and the fine carrier frequency offset estimate (62) is calculated in the time domain from reference symbols of reference signals repetitively received (60) at said communication equipment. An algorithm and an estimator module (90) for calculating a coarse carrier frequency offset are provided.

Abstract: The present invention relates to a first node (1) in a wireless communication system (2), where the first node (1) comprises at least two antenna ports (3, 4), and is arranged for communication with a second node (5) via a channel (H) by means of at least one antenna radiation lobe (6, 7, 8, 9). The second node (5) comprises at least two antenna ports (10, 11) and is positioned at a certain direction (12) in relation to the first node (1), and is arranged for transmitting one of at least two precoding weight set requests to the first node (1) at certain times. Each transmitted precoding weight set request is chosen in dependence of the channel (H) such that the first node (1) receives instructions for a certain beam-forming. The first node (1) is arranged to apply such a beam-forming that the precoding weight set requests received from the second node (5) have one certain distribution, of a set of at least one certain distribution, over a certain time period.

Abstract: A method for processing signals to be transmitted in a MIMO system from a transmitter having at least two transmitting antennas to a receiver having at least two receiving antennas on a frequency selective communication channel. The method comprises estimating elements of a channel matrix H(q?1) based on time delays and complex valued coefficients associated with the communication channel to provide an estimated frequency variation function of each element of the channel matrix, and pre-coding the signals to be transmitted based on the estimated frequency variation function for each element. The invention also relates to a MIMO system; and a transmitter and a receiver for use in a MIMO system.

Abstract: A method of and a precoding device and a communication device for precoding transmit data signals in a wireless Multiple-Input Multiple-Output, MIMO, channel transmission scheme for maximizing channel capacity of the MIMO system given available amounts of transmit power. The precoding is expressed in a complex precoding matrix (W), which is calculated involving individual transmit power constraints of the multiple outputs (71, . . . , 7t) of the MIMO channel. The individual transmit power constraints are comprised of predetermined individual output transmit power amplifier (PA1, . . . , PAt) limitations.

Abstract: The present invention relates to a node (1) in a wireless communication network, where the node (1) is arranged to receive at least two signals (y1(n), y2(n)) which correspond to at least two transmitted uncorrelated signal streams (x1(n), X2(n)) which have been transmitted to the node via a channel. The channel (2) is signals represented by means of a channel matrix (H(q?1)). The node (1) comprises a controllable filter structure (3) that is arranged to diagonalize the channel matrix (H(q?1)) such that a channel matrix estimation (?(q?1)) may be obtained. The present invention also relates to a corresponding method.

Abstract: The present invention relates to a method for identifying components in a telecommunication system, which method comprises representing a uniform linear array, ULA, antenna, having at least two antenna elements, by an array factor polynomial comprising at least two terms, each term having a certain weight (Wk); setting said weights (WK) to desired values such that a desired antenna radiation pattern is acquired. Furthermore, the method comprises the steps: changing the desired weights such that a number of sets of desired weights (Wk) is acquired, such that the ULA antenna scans a spatial portion, a certain scan corresponding to a certain set of desired weights, analyzing a received signal (h0) being represented by a received array factor polynomial having terms with certain received weights, which is parameterized by at least one pole; and using each corresponding set of desired weights (Wk) and received weights to determine the pole parameterization.

Abstract: The present invention relates to a solution for determining wireless communication cell characteristics related to wireless MIMO transmission mode and dynamically selecting suitable communication transmission mode for certain parts of the wireless communication cell. The solution uses a flatness spectrum analysis of received impulse response from a plurality of measurement points in the cell using a plurality of antennas in a wireless network access gateway, e.g. a base station.

Abstract: A method for simplifying calculations for pre-whitening in a G-RAKE receiver, comprising receiving at least two signals with at least two antennas via a channel, where each one of said received signals comprises time delayed and attenuated versions of the original signals. Each received signal forms a corresponding vector of received signal versions and the vectors form a matrix of received signals, where, due to correlation between the antennas, the received signals are correlated. Each version also comprises a certain amount of colored noise. The correlating effect of the antennas is estimated and formulated in matrix form and used to acquire essentially uncorrelated received signal vectors in an essentially uncorrelated received signal matrix. A calculated inverse of a covariance matrix of the calculated essentially uncorrelated signal vectors is used to pre-whiten the noise. A G-RAKE receiver arranged for applying the method above.

Abstract: The present invention relates to a method in a receiver for decoding at least two received communication signals, wherein the communication signals are modulated, pre-coded by a discrete Fourier transform and transmitted by means of single-carrier frequency division multiple access scheme (SC-FDMA). The method comprises the steps of: performing an antenna combining and equalization on a signal observed at the receiver; performing inverse discrete Fourier transform on a model of the observed signal; whitening a time domain model of the observed signal; and jointly detecting the received at least two communication signals by performing soft value calculations based on maximum likelihood detection of a whitened time domain model using a whitened time domain channel estimate.

Abstract: For compensating carrier frequency generation in communication equipment for radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based wireless radio communication system, in which reference signals known communication equipment are transmitted in a regular time repetitive manner, carrier frequency generation is compensated (63) by a calculated carrier frequency offset estimate. The carrier frequency offset estimate in the communication equipment is calculated from coarse (61) and fine carrier frequency offset estimates (62). The coarse carrier frequency offset estimate (61) is calculated in the frequency domain from reference symbols of a reference signal received (60) at the communication equipment and the fine carrier frequency offset estimate (62) is calculated in the time domain from reference symbols of reference signals repetitively received (60) at said communication equipment. An algorithm and an estimator module (90) for calculating a coarse carrier frequency offset are provided.

Abstract: The present invention relates to a method for acquiring a configuration of a re-configurable antenna, having at least two different antenna element configurations, where the antenna's element mutual coupling characteristics are known in advance in the form of an antenna coupling matrix (Ck(n)), the acquired configuration having a desired effect on a transmission channel, the method comprising the steps: setting an initial configuration of the re-configurable antenna, resulting in an initial coupling matrix (C0); estimating the transmission channel matrix (?(n)), which transmission channel matrix (?(n)) includes the effect of the antenna; calculating a generic transmission channel matrix ({tilde over (?)}(n)), which generic transmission channel matrix ({tilde over (?)}(n)) excludes the effect of the antenna; and extracting a coupling matrix (C) that provides a desired transmission channel matrix (H(n)), including the effect of the antenna.

Abstract: The present invention relates to a multi-stream communication system comprising a transmitting node provided with a polyphase antenna and a receiving node provided with an antenna arrangement configured to receive multiple data streams. The polyphase antenna has at least one group of multiple antenna elements, each group having N antenna elements. The transmitting node is also provided with at least one radio chain and a switch for each radio chain arranged to cyclically connect each radio chain to the antenna elements in one of the groups. The switch is configured to operate with a switching frequency fsw. The transmitting node is further configured to transmit M weighted symbols of an uncorrelated signal from each antenna element in each group, the M weighted symbols being less than or equal to N, and the receiving node is further configured to convert the received N data streams into each respective uncorrelated signal.

Abstract: The present invention relates to a first node (1) in a wireless communication system (2), where the first node (1) comprises at least two antenna ports (3, 4), and is arranged for communication with a second node (5) via a channel (H) by means of at least one antenna radiation lobe (6, 7, 8, 9). The second node (5) comprises at least two antenna ports (10, 11) and is positioned at a certain direction (12) in relation to the first node (1), and is arranged for transmitting one of at least two precoding weight set requests to the first node (1) at certain times. Each transmitted precoding weight set request is chosen in dependence of the channel (H) such that the first node (1) receives instructions for a certain beam-forming. The first node (1) is arranged to apply such a beam-forming that the precoding weight set requests received from the second node (5) have one certain distribution, of a set of at least one certain distribution, over a certain time period.

Abstract: A method and device for compensation of received signal components at a user equipment (UE) used for receiving signal components from a radio base station (RBS). The signal components have at least a first and a second polarization orientation, respectively. The intended reception of the signal component (Yh(n)) having the first polarization deviates from the polarization orientation of the transmitted signal component (Xh(n)) having the first polarization by a first angle (?), and the intended reception of the signal component (Yv(n)) having the second polarization deviates from the polarization orientation of the transmitted signal component (xv(n)) having the second polarization by a second angle (?). The method comprises the steps: determining the correlation values (Ryvv, Ryvy, Ryyv, Ryyy) for the received signals (Yh, Yv) at a first time (k) and a second time (m); using these values to determine the deviation angles (?, ?) performing said compensation using the deviation angles (?, ?).

Abstract: The present invention relates to an array antenna arrangement comprising at least two antenna sub-arrays and at least one antenna element in each antenna sub-array. The array antenna arrangement is adapted for calculation of a total covariance matrix (R) of a received signal vector (x). The array antenna arrangement further comprises at least one switch, where the number of switches corresponds to the number of antenna elements in each antenna sub-array. Each switch is connected to a respective radio chain, and is arranged to connect the antenna elements of a respective corresponding antenna sub-array to the respective radio chain cyclically. At least one full switch cycle, comprising a set of received signals for each switch configuration, is carried out for a calculation of the total covariance matrix (R). The present invention also relates to a corresponding method.

Abstract: The present invention relates to a solution for determining wireless communication cell characteristics related to wireless MIMO transmission mode and dynamically selecting suitable communication transmission mode for certain parts of the wireless communication cell. The solution uses a flatness spectrum analysis of received impulse response from a plurality of measurement points in the cell using a plurality of antennas in a wireless network access gateway, e.g. a base station.