Ceragon Networks Ltd.

Isaac Rosenhouse

Haggai Mizrahi

Gur Ballas

Oz Harel

Dudu Bercovich

Sharon Heruti

David Heller

Alon Harel

Yuval Vanunu

Oded Navi

Yaron Refaely

Yoav Heiman

A method for optimizing reception of a polarized single-carrier transmission, including transmitting a polarized single-carrier transmission to a receiver, receiving feedback from the receiver of a figure of merit of the polarized single-carrier transmission, and electronically changing polarization of the polarized single-carrier transmission based on the feedback. A single-carrier communication transmitter including a source for a polarized single-carrier transmission signal, a circuit for receiving feedback from a receiver describing a figure of merit of a received polarized single-carrier transmission, and a circuit for changing polarization of the polarized single-carrier transmission signal, based on the feedback. Related apparatus, systems and methods are also described.

Polarization pre-coding for a single carrier communication system

A method for a network controller to carry out automatic channel allocation for a network of wireless communication links between communication nodes, the method including determining an estimated signal attenuation between communication nodes in a network, allocating wireless channels, determined by a set of transmission parameters, to a plurality of wireless communication links in the network, based, at least in part, on the estimated signal attenuation, sending a message to a first communication node, the message instructing the first communication node to use a set of transmission parameters for communicating a first wireless communication link connecting the first communication node to a second communication node at an opposite end of the first wireless communication link, the transmission parameters based, at least in part, on the allocating wireless channels. Related apparatus and methods are also described.

Dynamic channel allocation

A single-carrier-modulation communication system for transmitting data over a wireless link, the communication system including, on a first side of a wireless link one single-carrier-modulation receiver associated with a single antenna, on a second side of the wireless link a plurality of antennas and a plurality of single-carrier-modulation transmitters, each one of the plurality of transmitters associated with one of the plurality of antennas, the transmitters each further associated with a pre-coding filter, and the plurality of transmitters are arranged to each transmit same data via a respectively associated pre-coding filter and the associated antenna, using the pre-coding filters to perform beam-forming to the one receiver. Related apparatus and methods are also described.

Transmit diversity and receive diversity for single carrier modulation

A method for symbol timing synchronization in multiple-input multiple-output (MIMO) communication, the method including transmitting a first symbol sequence including a preamble symbol sequence Sfrom a first transmitting location, transmitting a second symbol sequence from a second transmitting location, the first and second symbol sequences being modulated onto a same carrier frequency, receiving a first mixture of the first and the second symbol sequences at a first receiving location, cross correlating the first mixture with a symbol sequence Pthereby producing a first correlation output, and determining a first timing offset for receiving the first symbol sequence based, at least in part, on the first correlation output. Related apparatus and methods are also described.

Using sequences for symbol timing synchronization in single-carrier modulation MIMO communication systems

A method for a QAM receiver to decide a value of a received symbol of an N-point QAM constellation transmission including extracting coordinate values for the received symbol, and using a decision method for deciding the value of the received symbol based on the extracted coordinate values, in which the decision method for the N-point QAM constellation is updated based on a clustering of received symbols. A method for a QAM transmitter to modify an N-point QAM constellation including starting with an initial N-point QAM constellation, measuring a clustering of coordinates of the N-point QAM constellation, shifting coordinates of at least one symbol of the N-point QAM constellation, and producing a modified constellation with shifted coordinates, wherein the shifting is based on data describing a clustering of at least some symbols of the N-point QAM constellation. Related apparatus and methods are also described.

Adaptive slicer and constellations for QAM communications

A method for interference reduction in transmission of at least two single carrier frequency continuous communication beams including producing a first communication signal for a first digital communication link, producing a second communication signal for a second digital communication link, transmitting the first communication signal over a first continuous communication beam at a first frequency, transmitting the second communication signal over a second continuous communication beam at the first frequency, characterized by modifying the first communication signal using transmitter interference cancellation. A method for interference reduction in reception of at least two single carrier frequency continuous communication beams including receiving a first received signal from a first digital communication link, receiving a second received signal from a second digital communication link, modifying the first received signal, adding the modified first received signal to the second received signal, thereby producing a reduced-interference second received signal, characterized by the modifying of the first received signal being based, at least in part, on reducing an error rate of the reduced-interference second received signal. Related apparatus and methods are also described.

Frequency reuse in wireless point-to-point communication systems

A method for a receiver to estimate phase of a carrier wave, including receiving a carrier wave carrying pilot symbols and data symbols extending between the pilot symbols, determining phase of the carrier wave at received pilot symbols, and interpolating the phase of the carrier wave at points between pilot symbols based, at least in part, on an estimated phase of demodulated data symbols. Apparatus for estimate phase of a carrier wave, including a unit for determining phase of the carrier wave at received pilot symbols, and a unit for interpolating the phase of the carrier wave at points between pilot symbols based, at least in part, on an estimated phase of demodulated data symbols. Related apparatus and methods are also described.

Combining pilot-symbol-based phase estimation with data-symbol-based phase estimation

A method for estimating interference between a plurality of carrier signals in a multi-channel system including injecting pilot symbols into a first carrier signal and transmitting the first carrier signal, transmitting a second carrier signal, receiving at least the first carrier signal and the second carrier signal, and estimating interference between the received first carrier signal and the received second carrier signal based, at least in part, on measuring the received first carrier signal when a pilot symbol of the first carrier signal is received. A multi-channel communication system including a plurality of transmitters for a plurality of carrier signals, a pilot symbol injector for injecting silent pilot symbols into at least one of the carrier signals, a plurality of receivers for the plurality of carrier signals, and an interference estimator configured to estimate interference between at least two of the plurality of carrier signals based, at least in part, on receiving silent pilot symbols in at least one of the at least two of the plurality of carrier signals. Related apparatus and methods are also described.

Estimating interference in multi channel systems

A method for estimating a Signal to Noise Ratio (SNR) in a received signal including, for a fixed first set of a plurality of samples from the received signal, providing an initial noise estimate, starting with the initial noise estimate, iteratively improving the noise estimate, and estimating SNR based, at least partly, on the fixed first set of samples from the received signal and the noise estimate. Additional related apparatus and methods are also described.

SNR estimation

A variable data rate wireless transmitter configured to receive input of data from a plurality of input channels and transmit at least some of the data over a variable data rate wireless point-to-point communication link, wherein portions of the data are associated with priorities, and the wireless transmitter is configured to change transmission of at least some of the portions of the data, based, at least partly, on the priorities associated with the portions of the data, and on a data rate configured for transmitting the portions of the data over the variable data rate wireless communication link. A variable data rate wireless receiver configured to receive data over a variable data rate wireless point-to-point communication link, including a delay compensation buffer configured to maintain a substantially fixed delay between input of the data into a wireless transmitter transmitting the data and output of the data from the delay compensation buffer, by maintaining a suitable output rate of the data from the delay compensation buffer. Related apparatus and methods are also described.

Errorless and hitless variable data rate communications

A protected point-to-point ACM communication system including at least a first component and a second component configured to provide live functionality and backup functionality for each other, at least a first receiver and a second receiver configured to receive an ACM transmission, one or more quality detectors configured to estimate quality of the received transmission of at least the first receiver and the second receiver, wherein at least one of the quality detectors is configured to estimate the quality of the received transmission using blind detection, and a controller configured to switch the live functionality of the protected point-to-point ACM communication system from one of the first component and the second component to another of the first component and the second component, based, at least partly, on the estimated qualities of the received transmissions of at least the first receiver and the second receiver. Related apparatus and methods are also described.

Protected variable data rate communication systems

A method of data transmission which includes providing a plurality of data streams, having different content, modulating the different data streams by respective modulators, multiplexing the modulated data streams into a single data stream alternately in time, such that the resultant stream includes at any specific time signals from fewer than all the data streams and transmitting the multiplexed single data stream onto a transmission channel.

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Kiryat-Ono, Israel

Isaac Rosenhouse