Adaptive signal processing for infrared wireless CDMA systems

Infrared system provides a feasible alternative to radio system for indoor wireless communication. Direct spread CDMA format is a promising candidate for infrared transmission system. In indoor systems, transmission is severely impaired by noise and interference produced by artificial light. In this thesis, the performance of the DS CDMA indoor wireless infrared system on diffuse channels is analyzed by taking the effects of inter symbol interference (ISI) and electronic ballast florescent light interference into account. Moreover, to mitigate the effects of ISI and electronic ballast florescent light interference, an adaptive filter technique is proposed for noise cancellation and equalization. This is done by considering a ceiling bounce model for the channel and electronic ballast florescent light for noise. Analytical and simulation results show 7dB improvement in SINR and 10-15 times improvement in BER.

Adaptive signal processing for infrared wireless CDMA systems

Infrared system provides a feasible alternative to radio system for indoor wireless communication. Direct spread CDMA format is a promising candidate for infrared transmission system. In indoor systems, transmission is severely impaired by noise and interference produced by artificial light. In this thesis, the performance of the DS CDMA indoor wireless infrared system on diffuse channels is analyzed by taking the effects of inter symbol interference (ISI) and electronic ballast florescent light interference into account. Moreover, to mitigate the effects of ISI and electronic ballast florescent light interference, an adaptive filter technique is proposed for noise cancellation and equalization. This is done by considering a ceiling bounce model for the channel and electronic ballast florescent light for noise. Analytical and simulation results show 7dB improvement in SINR and 10-15 times improvement in BER.

Wireless Infrared Temperature Measuring System Design for Cable in Comprehensive Pipe Corridor

The comprehensive pipe corridor could realize the unified planning and construction of electricity, gas and communication, save urban land resources and beautify urban landscape. However, due to the narrow space and numerous pipelines in the pipe corridor, once the power cable fired, it would cause serious losses. This paper presented a wireless infrared temperature measuring system for power cable in the comprehensive pipe corridor based on infrared temperature measuring and radio frequency communication technology. This system used STM32 as the development platform, used AM2301 infrared temperature sensor to collect cable temperature, transmitted data of each temperature measuring node to the data management center through ESP8266 wireless module, and finally transferred the data of the management center to the server through RS485 bus, realizing the functions of multi-node temperature collection and wireless data transmission. It was verified by experiments that the measurement error of the temperature monitoring system was within 0.5°C, which could monitor the node temperature in real time, and provide guarantee for the safe operation and fire prevention of power cables in the comprehensive pipe corridor.

PROTECTION AGAINST UNAUTHORIZED ACCESS TO INFORMATION CIRCULATING IN WIRELESS INFRARED CHANNELS OF DATA TRANSMISSION

Цель исследования состоит в разработке методов защиты от несанкционированного доступа информации, циркулирующей в беспроводных ИК-каналах передачи данных. Показаны возможные способы несанкционированного доступа к каналу передачи данных от ИК-клавиатуры к компьютеру. Основной способ несанкционированного доступа к ИК-каналу передачи данных - это регистрация диффузно-отраженного от элементов интерьера излучения. Проведены теоретические оценки, подтверждающие возможность получения информации, циркулирующей в беспроводных ИК-каналах передачи данных при несанкционированном доступе. Рассмотрен типичный случай распространения излучения в помещении при использовании ИК-канала передачи данных при несанкционированном доступе. Неуполномоченный наблюдатель может регистрировать через оконный проем диффузно-отраженное излучение, используя специальную оптико-электронную систему. Для расчетов были приняты типовые фотометрические характеристики интерьера помещения и предельно достижимые на современном уровне техники характеристики фотоприемных устройств. Размер диаметра входного зрачка оптической системы принят не слишком большим из того соображения, что он не должен привлекать внимание (служить демаскирующим признаком). Предложен метод защиты информации, циркулирующей в беспроводных ИК-каналах передачи данных, основанный на формировании засветочных помех. Приведены схемы формирования засветочных помех. Для помехи может быть использовано диффузно-отраженной излучение или специально сформированное излучение, направленное на оконный проем помещения. The purpose of the research is to develop methods of protection against unauthorized access to information circulating in wireless infrared channels of data transmission. Possible ways of unauthorized access to the data transmission channel from the IR keyboard to the computer are shown. The main method of unauthorized access to the IR data transmission channel is the registration of radiation diffusely reflected from interior elements. Theoretical estimates have been carried out confirming the possibility of obtaining information circulating in wireless infrared channels of data transmission under unauthorized access. A typical case of propagation of radiation in room when using an IR data transmission channel with unauthorized access to information is considerd. An unauthorized observer can register diffusely reflected radiation through a window opening using a special optoelectronic system. For the calculations, the standard photometric characteristics of the interior of the room and the maximum achievable at the modern level of technology characteristics of photodetectors were taken. The size of the diameter of the entrance pupil of the optical system is taken not too large for the reason that optoelectronic system should not attract attention (serve as a unmasking feature). The method for protecting of information ciculating in optical wireless channels of data transmission, based on the formation of optical intentional noise, is proposed. It provides a brief overview of methods for generating pseudorandom sequences, wich can serv as a basis for the formation of an illumination noise channel. For optical intentional noise can be used diffusely reflected radiation or specially formed radiation, directed at the window opening of the room.

Getting to first base: Running is faster than sliding in collegiate baseball and softball players

Previous research has shown no significant differences in time required to reach a base when sliding head-first or feet-first, but few studies have compared running through and sliding into first base in baseball players, and none have included softball players. The purpose of the present study was to examine differences in time required to reach first base when running, sliding head-first, and sliding feet-first. Twelve female collegiate softball players (20.0 ± 1.3 years old) and 14 male collegiate baseball players (20.6 ± 1.6 years old) performed three trials each of running, sliding head-first, and sliding feet-first in a randomized, counterbalanced order with 1–2 min of rest between each trial. Testing was conducted in an indoor practice facility and trials were timed using a dual-beam wireless infrared timing system. Significant differences between the three approaches were found for both softball ( p < .001) and baseball players ( p < .001), and follow-up pairwise comparisons showed running through the base was significantly faster than sliding head-first ( p = .001 for softball, p = .009 for baseball) and feet-first ( p < .001 for softball, p = .002 for baseball). Differences between sliding head-first and feet-first were not significant in either group. Running through first base is significantly faster than sliding in collegiate baseball and softball players. Sliding into first base should only be attempted when avoiding a tag from or a collision with a fielder.