Huawei Technologies Co., Limited

Other

Dragonwave Inc.

Blinq Wireless Inc.

Ahikam Aharony

Taiwen Tang

Mahdi Zamani

Hoda Shahmohammadian

Weikun Hou

Zhuhong Zhang

Chuandong Li

Ho Ting Cheng

Ming Jian

Mikhail Prokoptsov

Jeroen Stroobach

Chunyao Li

Shaul Klein

The present disclosure relates to data transmission between a node and peer nodes. Interference alignment techniques are used to mitigate interference between the nodes on a line of sight channel A data stream is exchanged in two transmissions between the node and a peer node. The two transmissions are formed according to an interference alignment precoding matrix. The node may include linearly aligned antennas. To mitigate further the interference between the node and the peer node, a pair of these antennas is selected for communication with the peer node as a function of a distance between the node and the peer node and as a function of a wavelength of the communication. Channel state information may be exchanged between the node and the peer node for precoding matrix selection and for antenna selection. The antennas used for communication between the nodes and the peer nodes may be beamforming antennas.

Method and nodes for data transmission over a line of sight channel

An antenna arrangement includes antenna elements that are arranged, at each end of a Line of Sight communication link, into a selected shape. Distances between the antenna elements at each end of the link are determined based on a Line of Sight distance between the ends of the link and interference alignment between the antenna elements at the ends of the link. Different subsets of the antenna elements are coupled to communication modules at each end of the link. Signals are exchanged between the antenna elements at the ends of the link, and the signals are processed for interference alignment. The antenna element subsets may include two or more antenna elements, and may be unique or include common antenna elements that are common to multiple subsets.

Antenna arrangements for interference alignment in line of sight wireless communications

A microwave transmit system is provided that makes use of optical fiber to convey a microwave frequency source. A local oscillator produces a microwave frequency source in electrical form. A directly modulated laser receives the first microwave frequency source and produces an optical signal. An optical fiber is used to convey the optical signal from the laser to a photodetector. The photodetector receives a first component of the optical signal and converts the first component of the optical signal to a second microwave frequency source in electrical form. A microwave modulator performs microwave modulation using the second microwave frequency source, and a microwave antenna configured to transmit an output of the first microwave modulator. For MIMO operation, there can be a second microwave modulator. The microwave frequency source can also be conveyed to the second microwave modulator using optical fiber, or the source can be proximate to one of the two microwave modulators, and conveyed to the other of the two microwave modulators using optical fiber.

System and method for photonic distribution of microwave frequency electrical signal for distributed microwave MIMO communications

Encoding and decoding systems are provided for reduced latency at the decoder. In the encode error detection codewords are produced from source bits. The error detection codewords are then encoded with a systematic error correction encoder to produce a set of parity bits. All of the systematic code source bits and at least some of the parity bits are mapped to modulation symbols for transmission. In the decoder, two signal processings are performed in parallel, one based on soft bit decisions and the other based on hard bit decisions. The soft bit decisions are processed using a systematic error correction decoder. The hard bit decisions are processed by re-encoding error detection codewords to produce parity bits. If the produced parity bits match received parity bits, then the hard bit decisions are reliable and are output without waiting for the result of the systematic error correction decoder.

Software defined network with selectable low latency or high throughput mode

A duplex communication system includes a duplexer for transmitting and receiving signals, a transmitter part connected to the duplexer, and a receiver part connected to the duplexer, the receiver part comprising an amplifier for amplifying a received signal to provide an amplified received signal and a demodulator for downconverting the amplified received signal, and a second-order intermodulation distortion (IMD) compensation module for compensating for second-order intermodulation distortion. The system also includes an adaptive filtering module that obtains a transmitter reference signal, generates filter coefficients for the IMDcompensation module and also adjusts a direct current (DC) bias of the demodulator based on the reference signal.

Receiver path distortion mitigation using adaptive filter feedback

Phase noise estimation and cancellation as disclosed herein may allow cost-efficient increase of capacity in communications by enabling very high QAM levels. The proposed solution is potentially applicable to any single carrier applications where phase noise is a limiting factor and a required order of modulation is very high. For example, disclosed embodiments may enable high QAM levels for microwave backhauls despite severe phase noise sensitivity. One embodiment involves a pilot-aided and BCJR-based sequential search algorithm that accurately estimates and subtracts fast-varying phase noise symbol-by-symbol. Residual BER performance is evaluated under the most challenging phase noise scenarios. FPGA emulation results show detection and removal of a significant amount of phase noise and zero BER performance even for complex 1K-QAM and above.

Phase noise estimation and cancellation

Cross-phase interference occurs in dual polarized or orthogonal polarized microwave links when independent local oscillators (LOs) are utilized in each outdoor unit (ODU) transceiver operating on the same frequency channel. If the cross-phase noise is not compensated the performance of the microwave link will be degraded. In order to reduce cross-phase noise two or more pilot symbols are utilized to enable cross-phase noise estimates to be determined at the receiver of the microwave link. The pilot symbols enable a cross-phase noise compensation factor to be determined for the signal from the one or more cross-phase noise estimates. The received signal can then be compensated using the estimated cross-phase noise compensation factor.

Cross-phase estimation for dual polarized microwave transceiver

Methods and apparatus for calibrating an antenna array are provided. A limited number of antenna elements of the array are operated to broadcast a signal. The signal carries information relevant to operation of a communication network, for receipt by other devices. By using one or a limited number of antenna elements, a radiation pattern covering a wide area is achieved. Concurrently, transmission of the broadcast signal is monitored using another one or more antenna elements of the array, operating in a receive mode. The monitored signal is used in an antenna array calibration operation. The procedure is repeated for various different transmitting and receiving antenna elements, resulting in a sequence of broadcasts using different parts of the array. The calibration results can be used to correct for operating errors such as phase shifter errors. The corrected phase shifters can then be used for beamforming during another phase of communication.

Method and apparatus for beamforming calibration in point to multipoint communication systems

Provided is an apparatus and method for transmitting and receiving polarized signals. Wireless communication with multiple polarized signals may experience greater attenuation on one polarized signal than another polarized signal. The polarized signal that is more attenuated limits overall throughput for the wireless communication. According to an embodiment of the invention, signals undergo rotation processing with a transformation involving a rotation matrix prior to transmission. Each polarized signal that is transmitted is based on a different weighted combination of the signals. The rotation processing can be performed with an objective that signals recovered at a receiver have comparable signal quality, which can increase overall throughput. In some implementations, the rotation processing is performed based on feedback to dynamically adjust the rotation processing.

Apparatus and method for transmitting and receiving polarized signals

Provided is an apparatus and method for transmitting and receiving wireless signals. A transmitting apparatus has a signal processor and a transmitter. The signal processor is configured to generate a signal having a middle channel and at least one side channel. The transmitter is configured to wirelessly transmit the signal subject to a spectral mask that has shoulder regions. According to an embodiment of the invention, the signal processor generates the signal such that each side channel is positioned in one of the shoulder regions of the spectral mask. In this manner, bandwidth from the shoulder regions can be utilized by one or more side channels. Also provided is a receiving apparatus having a receiver configured to wirelessly receive the signal, and a signal processor configured to process the signal.

Apparatus and method for transmitting and receiving wireless signals subject to a spectral mask

A communication system includes multiple communication nodes and a processor. The communication nodes are configured to communicate over a tropospheric scattering channel. The processor is configured to communicate with the communication nodes over a secondary communication network, different from the tropospheric scattering channel, so as to control communication of the communication nodes over the tropospheric scattering channel.

Automatically-reconfigurable tropospheric scatter communication link

A method and system is disclosed for precoding in a two transmit antenna MIMO system, for example, a wireless backhaul network. The method only uses the first column of the 2&#xd7;2 precoder as the feedback information. When the feedback information is available to the transmitter, the transmitter performs an interpolation and reconstruction procedure to obtain the precoder matrix for each subcarrier. The method offers no significant loss in performance, with reduced computational complexity and feedback overhead compared to conventional known matrix representation methods.

Method and apparatus for precoding in a two transmit antenna closed-loop MIMO fixed wireless backhaul network

Octagonal non-rectangular Quadrature Amplitude Modulation (QAM) is disclosed. Grid points from a uniform rectangular grid, which includes points that have equal horizontal and vertical spacing, are selected to form a non-rectangular octagonal grid that approximates an octagonal shape. QAM symbols are mapped to respective grid points in the non-rectangular octagonal grid to form a non-rectangular octagonal QAM constellation that also approximates the octagonal shape. Input signals can then be modulated using the non-rectangular octagonal QAM constellation.

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Ottawa, Canada

Ahikam Aharony