Abstract: A user equipment device operating in a cellular communications system includes a neighbor cell searcher configured to receive a first reference signal transmitted from a base station of a first cell of the cellular communications system and determine first channel information associated with the first cell, and receive a second reference signal transmitted from a base station of a second cell of the cellular communications system and determine second channel information associated with the second cell. A channel estimator is configured to generate correlations between times and frequencies associated with reception of the first reference signal and the second reference signal, and generate a channel estimate corresponding to the first reference signal based on the first channel information, the second channel information, and the correlations.

Abstract: A system includes a network interface and one or more processors. The processors are configured to track a first pattern with which a user terminal consumes one or more data services while served by a home network specified for the user terminal, to track a second pattern with which the user terminal consumes the one or more data services while served by one or more networks other than the home network, to estimate a reduction in usage of the one or more data services between the first and second patterns, and to selectively enable at least one data service to the user terminal by the networks other than the home network, based on the estimated reduction in usage.

Abstract: A method includes prefetching to a memory of a user device one or more content segments of a content item, which includes multiple content segments and an index that specifies storage locations of the content segments. The index is modified to indicate that the prefetched content segments are to be retrieved from the memory of the user device. At least part of the content item is delivered by retrieving at least some of the content segments in accordance with the modified index.

Abstract: A method in a receiver includes receiving a signal that traversed a multipath channel having a channel response, so as to produce a received sequence of samples that are indicative of the channel response. Using a predefined similarity measure, multiple metrics between the received sequence of samples and multiple respective candidate sequences of samples are calculated by the receiver. Each candidate sequence includes a combination of one or more dominant signal components having respective sample delays, and each candidate sequence corresponds to a channel multipath candidate that has one or more channel paths at the respective sample delays. The channel response is estimated by the receiver, by selecting the candidate sequence that best matches the received sequence, the selecting being based on the similarity measure.

Abstract: A method includes caching content items in a cache memory of a communication terminal connected to a communication network. A content item, which is cached in the cache memory, is presented to a user of the communication terminal. An extent of freshness of the cached content item presented to the user is assessed. Presentation of the cached content item is conditionally modified depending on the assessed extent of freshness.

Abstract: A method includes, in a receiver, receiving a signal carrying data using multiple antennas, so as to produce multiple respective input signals. The input signals are divided into two or more subsets. The input signals within each of the subsets are combined in a first diversity-combining stage, to produce respective intermediate signals. In a second diversity-combining stage, the intermediate signals are combined to produce an output signal. The output signal is decoded so as to reconstruct the data carried by the received signal.

Abstract: A method includes, in a mobile communication terminal, storing a mathematical model for computing a covariance matrix of data conveying signals that are received at the mobile communication terminal. At least a first data conveying signal is received in the mobile communication terminal, and one or more signal components required by the model are extracted from the first data conveying signal. A determination is made whether the model is suitable for computing the covariance matrix for the first data conveying signal based on a predefined rule. The covariance matrix is computed in the mobile communication terminal using at least one of the model and an empirical-based estimation of the covariance matrix. The covariance matrix is selected in response to the determination.

Abstract: A method includes prefetching advertisement items from one or more advertisement sources over a network to an advertisement cache of a user terminal. In response to an indication that a content item is expected to be consumed by the user terminal, a request for an advertisement item to be presented in association with the content item is sent from the user terminal over the network. An instruction to present a selected advertisement item is received in the user terminal in response to the request. If the selected advertisement item is available in the advertisement cache, the selected advertisement item is retrieved from the advertisement cache, and the retrieved advertisement item is presented in association with the content item.

Abstract: Apparatus and methods are described, including a method for use with a first content delivery network (CDN) and a second CDN that are used by a content source. A processor is used to identify that a device is requesting an exchange of content with the content source, identify a property of the requested exchange of content, and based on the property, select one of the first CDN and the second CDN. Subsequently, content is exchanged between the device and the selected CDN. Other embodiments are also described.

Abstract: A method includes, in a receiver, computing soft decoding metrics for decoding a received signal. The soft decoding metrics are stored in compressed form in a memory buffer. The soft decoding metrics in the compressed form are retrieved from the memory buffer, the retrieved soft decoding metrics are decompressed, and the received signal is decoded using the decompressed soft decoding metrics.

Abstract: A method for content delivery includes defining a guaranteed prefetching mode, in which content is continuously prefetched from a content source to a communication terminal of a user so as to maintain the communication terminal synchronized with the content source. One or more time-of-day intervals, during which the user is expected to access given content, are identified. During the identified time-of-day intervals, the given content is prefetched from the content source to the communication terminal using the guaranteed prefetching mode.

Abstract: A method includes receiving in a receiver transmissions from a serving cell that serves the receiver and from one or more neighbor cells. The transmissions are received via multiple receive antennas to produce multiple respective output signals. The multiple output signals are weighed with respective weights, and the weighted output signals are combined to produce a combined output signal. The weights are selected so as to form a composite antenna pattern having a first antenna gain in one or more first directions that point toward the neighbor cells, and a second antenna gain, lower than the first antenna gain, in a second direction that points toward the serving cell. Characteristics of the one or more neighbor cells are measured by processing the combined output signal in which the transmissions received from the serving cell are attenuated.

Abstract: A method includes, in a receiver, receiving a signal carrying data using multiple antennas, so as to produce multiple respective input signals. The input signals are divided into two or more subsets. The input signals within each of the subsets are combined in a first diversity-combining stage, to produce respective intermediate signals. In a second diversity-combining stage, the intermediate signals are combined to produce an output signal. The output signal is decoded so as to reconstruct the data carried by the received signal.

Abstract: A method includes holding in a memory of a communication terminal multiple predefined vectors, each including signal autocorrelation values computed for a respective Doppler shift. A signal is received, and empirical autocorrelation values are calculated for the received signal. An actual Doppler shift of the received signal is estimated by selecting, from among the predefined vectors, a vector whose autocorrelation values best match the empirical autocorrelation values of the received signal.

Abstract: A method for communication includes configuring a communication system that includes a transmitter and a receiver with first precoding matrices for mapping up to N data streams onto N transmit antenna ports of the transmitter. Each of at least some of the first precoding matrices are derived from respective second and third precoding matrices. The second and third precoding matrices are configured for mapping data onto respective numbers of transmit antenna ports that are less than N. The data streams are mapped onto the N transmit antenna ports using a precoding scheme based on one of the first precoding matrices. The mapped data streams are transmitted over the N transmit antenna ports from the transmitter to the receiver.

Abstract: A method includes receiving a signal in a communication terminal. A power spectral density, which the signal would have under full-load conditions of a transmitter transmitting the signal, is estimated based on the received signal. An operation is performed in the communication terminal using the estimated power spectral density.

Abstract: A method includes holding in a memory of a communication terminal multiple predefined vectors, each including signal autocorrelation values computed for a respective Doppler shift. A signal is received, and empirical autocorrelation values are calculated for the received signal. An actual Doppler shift of the received signal is estimated by selecting, from among the predefined vectors, a vector whose autocorrelation values best match the empirical autocorrelation values of the received signal.

Abstract: A method includes receiving a signal in a frequency band, which is assignable at least to a communication protocol in which Cyclic Prefixes (CP) are added to symbols having a predefined symbol interval. Multiple autocorrelations of the received signal are computed with a fixed time offset that depends on the symbol interval defined in the communication protocol, and the multiple autocorrelations are accumulated to produce a cumulative autocorrelation. An identification is made, based on the cumulative autocorrelation, whether the received signal is formatted in accordance with the communication protocol.

Abstract: A method includes, in a mobile communication terminal, receiving from at least first and second base stations, which cooperate in a coordinated transmission scheme, signals that are transmitted over respective first and second communication channels. Respective channel measures are calculated for the communication channels based on the received signals. First and second feedback data, which are indicative of the respective channel measures of the first and second communication channels, are formulated such that the first feedback data has a first data size and the second feedback data has a second data size, different from the first data size. The first and second feedback data are transmitted from the mobile communication terminal to at least one of the base stations.

Abstract: A method includes receiving reference signals in a mobile communication terminal, which is designed to receive data-carrying signals that are transmitted from a base station using one of multiple predefined Modulation and Coding Schemes (MCSs). One or more pre-calculated mappings between Signal-to-Noise Ratio (SNR) and error rate for one or more of the MCSs are held in the communication terminal. The pre-calculated mappings are adjusted according to one or more transmission parameters of the data-carrying signals. Measures indicative of respective actual spectral efficiencies that are achievable by the MCSs are estimated based on the adjusted mappings using the received reference signals. A preferred MCS is selected based on the estimated measures, and feedback that is indicative of the preferred MCS is sent to the base station.