A method of sparse digital cancellation of receiver nonlinear distortion in carrier aggregation systems is proposed. A reference signal generator generates possible candidate reference signals to be included in a dictionary matrix D. A sparsity-based solution is then applied to dynamically select reference signals based on the RF transceiver configuration. Based on the auto-correlation and cross-correlation with an observed radio signal, a subset of reference signals is selected from the dictionary matrix to match the distortion signal. The number of selected reference signals is flexibly determined based on the design constraints on complexity and power consumption. A greedy sparse estimation approaches, e.g., Orthogonal Matching Pursuit (OMP) can be used for reference signal selection. The reference signal selection is dynamic and adapts itself for different channel responses through correlating the observed radio signal with the dictionary reference signals.

Wireless communications systems and methods related to over-the-air uplink-downlink (UL-DL) reciprocity calibration. A central unit transmits downlink (DL) calibration reference signal (RS) and a calibration request. The central unit receives, in response to the calibration request, a first uplink (UL) calibration RS and a first DL channel estimate associated with a first transmission point (TP) and a first wireless communication device. The central unit transmits a DL coordinated multipoint (CoMP) joint transmission signal according to an uplink-downlink (UL-DL) reciprocity calibration. The UL-DL reciprocity calibration is based on at least a first UL channel estimate based on the first UL calibration RS, the first DL channel estimate, a second UL channel estimate associated with a second TP and the first wireless communication device, and a second DL channel estimate associated with the second TP and the first wireless communication device.

The present application relates to an adaptive filter using resource sharing and a method of operating the adaptive filter. The filter comprises at least one computational block, a monitoring block and an offset calculation block. The computational block is configured for adjusting a filter coefficient, c.sub.i(n), in an iterative procedure according to an adaptive convergence algorithm. The monitoring block is configured for monitoring the development of the determined filter coefficient, c.sub.i(n), during the performing of the iterative procedure. The offset calculation block is configured for determining an offset, Off.sub.i, based on a monitored change of the filter coefficient, c.sub.i(n), each first time period, T.sub.1, and for outputting the determined offset, Off.sub.i, to the computational block if the determined filter coefficient, c.sub.i(n), has not reached the steady state. The computational block is configured to accept the determined offset, Off.sub.i, and to inject the determined offset, Off.sub.i, into the iterative procedure.

A method and apparatus may include receiving a transmission. The method can also include determining a sparsifying dictionary that sparsely approximates a data vector of the transmission. The determining the sparsifying dictionary includes performing a fast Fourier transform and/or an inverse fast Fourier transform. The method also includes configuring a filter based on the determined sparsifying dictionary.

A method of estimating a channel for mobile systems with insufficient cyclic prefix length, wherein the channel comprises a plurality of multipath components (,), includes: receiving a signal (y.sub.n) comprising a plurality of contributions of a transmit signal (x.sub.n[k], x.sub.n-1[k]) transmitted during a plurality of transmission time intervals (n, n-1) on a plurality of sub-carriers of known pilots (kP.sub.b) and a plurality of sub-carriers of unknown data (k.Math.P.sub.b); determining an estimate of the plurality of multipath components (,) based on a probabilistic relation between the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal, wherein the plurality of first contributions are transmitted during adjacent transmission time intervals (n, n-1), and an observation of the received signal (y.sub.n[k]) at a subcarrier (kP.sub.b) of the known pilots, wherein the probabilistic relation is based on statistical properties of the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal.

One embodiment provides a network controller. The network controller includes a modulation module. The modulation module includes a high rate (HR) bit sequence generator configured to generate a first high rate bit sequence, encoder circuitry configured to encode a first low rate bit stream, the first low rate bit stream comprising backchannel information, and modulation circuitry configured to modulate the encoded first low rate bit stream onto the first high rate bit sequence. The network controller further includes transmit circuitry configured to transmit the modulated first HR bit sequence to a link partner during a link initialization period.

Wireless communications systems and methods related to over-the-air uplink-downlink (UL-DL) reciprocity calibration. A central unit transmits downlink (DL) calibration reference signal (RS) and a calibration request. The central unit receives, in response to the calibration request, a first uplink (UL) calibration RS and a first DL channel estimate associated with a first transmission point (TP) and a first wireless communication device. The central unit transmits a DL coordinated multipoint (CoMP) joint transmission signal according to an uplink-downlink (UL-DL) reciprocity calibration. The UL-DL reciprocity calibration is based on at least a first UL channel estimate based on the first UL calibration RS, the first DL channel estimate, a second UL channel estimate associated with a second TP and the first wireless communication device, and a second DL channel estimate associated with the second TP and the first wireless communication device.

The patent application relates to a method for recovering a sparse communication signal from a receive signal, the receive signal being a channel output version of the sparse communication signal, the channel comprising channel coefficients being arranged to form a channel matrix, the method comprising determining a support set indicating a set of first indices of non-zero communication signal coefficients from the channel matrix and the receive signal, determining an estimate of the sparse communication signal upon the basis of the support set, the channel matrix and the receive signal, determining second indices of communication signal coefficients which are not indicated by the support set, and determining the sparse communication signal upon the basis of the support set, the estimate of the sparse communication signal, the second indices and the channel matrix.

One embodiment provides a network controller having physical interface (PHY) circuitry that includes transmitter circuitry configured to transmit data frames to a link partner over a channel link. The network controller also includes a link speed cycling module configured to cause the transmitter circuitry to transmit data frames to the link partner using at least one high rate link speed. The network controller also includes an equalization presets module configured to apply at least one equalization preset setting to the transmitter circuitry while the transmitter circuitry is transmitting the data frames to the link partner. The link speed module is further configured to cause the transmitter circuitry to dwell, for a transmitter dwell time period, for the at least one equalization preset setting at the at least one high rate link speed. The transmitter dwell time period allows the link partner to lock on to the transmitted data frames.

A mobile telecommunications network includes a core and a radio access network having a radio for wireless communication with mobile terminals registered with the network. The radio access network includes a controller operable to control the use of network resources by the mobile terminals. The controller may include an application programming interface, API, which provides a consistent interface to a multiplicity of applications hosted on the control mean. The controller may be provided at an access node site and/or a gateway site.