H04L25/03006

Adaptive equalization using correlation of data patterns with errors
11082268 · 2021-08-03 · ·

An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.

APPARATUS AND METHOD FOR ADJUSTING BOTH A CYCLIC PREFIX LENGTH AND A SYMBOL INTERVAL OF A COMPLEX SYMBOL SEQUENCE
20210212048 · 2021-07-08 · ·

[Object] To adaptively adjust a symbol interval in accordance with a communication environment.

[Solution] An apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that control information for adjusting a symbol interval in a complex symbol sequence into which a bit sequence is converted is transmitted from the communication unit to a terminal, the control information being set on a basis of a predetermined condition.

Optical communication system

The disclosure relates to technology for signal transmission in an optical communication system. An optical transmitter comprises a directly modulated laser (DML) configured to generate a modulated optical signal in response to a modulation signal. The modulated optical signal comprises a first frequency corresponding to a logical one value in the modulation signal and a second frequency corresponding to a logical zero value in the modulation signal. The modulated optical signal has a modulation symbol rate of “R”. The transmitter comprises a controller configured to control the DML to establish a target frequency gap between the first frequency and the second frequency. The transmitter also comprises an optical band pass filter (OBPF) coupled to the DML to receive the modulated optical signal and output a filtered optical signal. The OBPF has a 3-dB bandwidth of less than R.

REMOTE INTERFERENCE IDENTIFICATION AND MITIGATION
20210234731 · 2021-07-29 ·

Method, systems and devices for identifying and mitigating remote interference, e.g. a downlink transmission from a remote network device interfering with uplink transmissions of another network device, are described. One example method for identifying remote interference includes determining that an interference type is a remote interference, and transmitting, in response to the determining, a reference signal indicative of a resource that was affected by the remote interference. Another example method for identifying remote interference includes detecting a reference signal in a frame, and determining a resource that was affected by a remote interference based on a position of the reference signal in the frame.

Constellation selection threshold adaptation for slicer

System and method of adapting thresholds for constellation selection based on statistic distributions of received data symbols. To determine an adapted threshold, an expected ratio of received symbols with values in a certain range is preset based on an expected statistic distribution of data symbols across the multiple constellations. A first and a second ratios are defined based on the expected ratio, the first ratio being the expected ratio minus an error ratio and the second ratio being the expected ratio plus the error ratio. A first value is determined which makes the received symbols in a firs range to constitute the first ratio of a set of slicer inputs. A second value is determined which makes the received symbols in the second range to constitute the second ratio of a set of slicer outputs. The adapted threshold is then obtained based on the first and the second value.

Single-ended vectored DSL system
11082089 · 2021-08-03 · ·

As fiber networks are extended closer to the subscriber, 5G small cell, multi-dwelling units, and office buildings, in some applications Digital Subscriber Line (DSL) becomes an extension for the fiber network over the last 100 to 300 meters of twisted wire-pair telephone lines. Utilizing techniques such as bonding of coterminous twisted wire-pairs, increasing the bandwidth into the VHF spectrum, emerging 5.sup.th generation DSL technology is poised to deliver aggregate bandwidth approaching 10 Gb/s. Underpinning the capability to reach these speeds over twisted wire-pair, requires Vectored DSL to cancel Far-End crosstalk (FEXT); the dominant impairment to high-speed DSL. Improving on current Vectored DSL technology, both one-sided and two-sided, through utilization of Single-Ended Vectored DSL to cancel FEXT offers significant improvements to several aspects of deploying DSL at gigabit speeds.

Method and apparatus for training a full-duplex communication link

During a training procedure for communicating via a full-duplex communication link, a first communication device receives training information from a second communication device. The training information corresponds to first signal processing parameters developed at the second communication device for use by the second communication device to process signals received by the second communication device via the full-duplex communication link. After receiving the training information from the second communication device, the first communication device develops second signal processing parameters to be used by the first communication device to process signals received by the first communication device via the full-duplex communication link. The second signal processing parameters are developed using the training information received from the second communication device.

DECODING UPLINK IN A MASSIVE MULTIPLE INPUT MULTIPLE OUTPUT WIRELESS COMMUNICATION SYSTEM FOR AN OPEN RADIO ACCESS NETWORK

There is provided a technique of decoding an uplink in a multiple input multiple output wireless communication system in an open radio access network having an open distributed unit (O-DU) and an open radio unit (O-RU). The O-DU (a) constructs a combining matrix for a resource block, and (b) sends the combining matrix to the O-RU. The O-RU (a) utilizes the combining matrix to compress signals on NR antennas per subcarrier into M values, where NR is a number of antennas, and M is less than NR, and (b) sends the M values per subcarrier to the O-DU.

PHASE VARIATION COMPENSATION DEVICE, PHASE VARIATION COMPENSATION METHOD AND COMMUNICATION DEVICE

A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.

Phase variation compensation device, phase variation compensation method and communication device

A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.