On the Probability of Erasure for MIMO-OFDM

Detecting the presence of a valid signal is an important task of a telecommunication receiver. When the receiver is unable to detect the presence of a valid signal, due to noise and fading, it is referred to as an erasure. This work deals with the probability of erasure computation for orthogonal frequency division multiplexed (OFDM) signals used by multiple input multiple output (MIMO) systems. The theoretical results are validated by computer simulations. OFDM is widely used in present day wireless communication systems due to its ability to mitigate intersymbol interference (ISI) caused by frequency selective fading channels. MIMO systems offer the advantage of spatial multiplexing, resulting in increased bit-rate, which is the main requirement of the recent wireless standards like 5G and beyond.

Bistatic Underwater Optical-Electronic Communication: Field Experiments of 2017-2018

The article describes the results of experiments with underwater bistatic optoelectronic communication systems with scattered laser radiation as the source of information and the valid signal. The information reception distance of up to 40 m was gained in field conditions of lake water.

Detecting Ultra Low Carbon and Sulfur Contents in Steel by Using Infrared Absorption Method

The detection of carbon with the contents ranging from 0. 000 5 % to 0.010%, and of sulfur with the contents ranging from 0.000 2% to 0.010%, has become an inevitable requirement for steelmaking process control. Due to the extreme low carbon and sulfur contents, using infrared carbon sulfur technical analysis has lower peak value than the background value of the instrument, and it is difficult to control the best analysis conditions of obtained valid signal; in addition, the small errors brought by crucible blank, sample weight, and uniformity of the samples may have great impact on the detection results. To solve this technical problem, this study gives up the single point calibration applied by infrared absorption method, but uses linear calibration method to detect ultra low carbon and sulfur contents in steel, which effectively meets the demand of manufacturers on the development of high-value-added products, and provides reliable data for production.

Design of an Intelligent Point-to-Point Swing Arm Controller

The point-to-point swing arm test is very important for large arms which have swing arm movement. Traditional point-to-point swing arm controller is relay control mode. The mode has many shortcomings, such as big volume, high power consumption, low stability, and so on. An intelligent point-to-point swing arm controller, using MCU as the control core, was designed for this reason. It was mainly composed of switch signal detecting module, solenoid valve drive module, USB storage interface module and MCU control module. According to the requirements of test, the controller was able to detect the valid signal of limit switch and control commutation operation of solenoid valve, meanwhile it could record the movement time between one point and another point, the time the arm swayed and the moment information, and these above information would be stored in USB memory. It has some advantages of small size, low power consumption, high stability and flexible functions.

Time-Frequency Correlation Method for Improving the Accuracy in Detecting Leaks in Pipelines

This report offers the solution that allows increasing the correlation leak detectors accuracy to a certain extend. This solution is based on signals frequency spectrum data and signal analysis time-frequency correlation method development. The idea is to analyze the correlation of two signals, to determine valid signal frequency limits and to set on this basis frequency filters parameters to improve signal-to-noise ratio.