This study is based on applying a non-linear mapping method, here the unscented Kalman filter; to estimate and optimize data rate resulting from the arrival rate having a Poisson distribution in an orthogonal frequency division multiplexing (OFDM) transmission system. OFDM is an emerging multi-carrier modulation scheme. With the growing need for quality of service in wireless communications, it is highly necessary to optimize resources in such a way that the overall performance of the system models should rise while keeping in mind the objective to achieve high data rate and efficient spectral methods in the near future. In this study, the results from the OFDM-TDMA transmission system have been used to apply cross-layer optimization between layers so as to treat different resources between layers simultaneously. The main controller manages the transmission of data between layers using the multicarrier modulation techniques. The unscented Kalman filter is used here to perform nonlinear mapping by estimating and optimizing the data rate, which result from the arrival rate having a Poisson distribution.

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The integrated Network Enhanced Telemetry (iNET) environment is meant to build and improve on the existing unidirectional legacy telemetry links. The optimized network would have to be capable of providing bi-directional, spectrally efficient, reliable, dynamically allocated, real time or near real time access to video and other types of test data over a shared bandwidth, high capacity network. Developed specifically for providing a reliable means of communications for large numbers of users, cellular technology seems particularly suited to addressing iNET’s needs. This paper investigates the creation of a cellular model for enhanced throughput for data users wherein a user would dynamically be allocated high data rates dependent on parameters such as the received signal to noise ratio (SNR). Our future work will develop the average data performance, comparing both the time division multiple access (TDMA) and code division multiple access (CDMA) environments for potential application in iNET.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / A traditional Receiver, Modulator, Bit Synchronizer, Frame Synchronizer and Front-End Processor (FEP) with local RAID storage from numerous satellite ground station equipment providers is typically used to satisfy current needs in mission ground stations. The development of Software Defined Radios (SDRs) with reprogrammable personalities has led to the consolidation of these processing elements, and will become the standard for years to follow. CVG-Avtec Systems, Inc. has been a pioneer in the SDR industry, integrating several ground station functions into a one system solution. Its High Data Rate Modem (HDRM) architecture replaces racks of previous generation equipment, providing greater functionality in a smaller footprint. The Field Programmable Gate Array (FPGA) based HDRM is a one system solution that inputs Intermediate Frequency (IF) data and outputs packetized data over IP for data distribution. These new architectures are capitalizing on the revolution in electronics and networking technologies. This paper will discuss the architecture of the HDRM and how it optimizes ground station data processing in a high-rate environment.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Power line communications (PLC)-based transceivers provide an alternative to establishing dedicated aircraft Ethernet networks. Adding new aircraft functionality or installing special purpose instrumentation often requires significant engineering and aircraft down time to complete. PLC-based networks can reduce project cost and schedule by enabling localized aircraft modifications and leveraging existing aircraft wiring for the Ethernet medium. PLC standards continue to evolve and achieve greater throughput rates and noise mitigation. Ethernet communications have been tested over AC and DC power busses, data busses, and discrete wiring. PLC networks have been successfully demonstrated in avionics test beds and aircraft (including live video transfers) without causing interference to the basic systems or the underlying wiring functionality. PLC transceivers provide a cost effective solution to the adding Ethernet capabilities or Ethernet-based subsystems to existing aircraft.

No description available.

Generation by generation, wireless communication has advanced in various ways and provided reliable communication services at higher and higher data rates to the needs of more and more advanced wireless applications. Two main issues towards future wireless communications are high-speed transmission technique to provide high data rate services and reliable communication to ensure the required performance. This dissertation focuses on these two issues. Since orthogonal frequency division multiplexing (OFDM) has emerged as an enabling technique for high-speed transmission in dispersive environments, major and fundamental issues in OFDM, namely, synchronization, channel estimation, and peak-to-average power ratio (PAPR) reduction are addressed. For the required reliability, automatic repeat request (ARQ) schemes must be applied. Due to large potential performance improvement, adaptive ARQ schemes have recently attracted much attention and are also addressed here. We propose two improved OFDM timing synchronization methods which overcome the drawbacks of existing methods. We present a time-domain-based OFDM channel estimation which outperforms the existing time-domain-based approach and has a similar performance to the linear minimum mean square error estimator but with less complexity. For OFDM systems with transmit diversity, we present a reduced complexity channel estimation which has a comparable performance to the existing method for channels with relatively small delay spreads, but achieves much complexity saving. An approach to find the number of most significant channel taps is described for diverse channel environments. We analyze the effect of non-sample-spaced channel path on the channel estimation and propose a modification for further improvement. Timing synchronization, frequency synchronization and channel estimation are usually addressed separately. Since they can affect each other, the idea of jointly addressing all of them together is much desirable and pursued here. This joint approach reflects the actual performance and gives an opportunity to exploit some information obtained from one task in another, hence promising more improvement. The proposed training preamble-based joint timing and frequency synchronization utilizes some information from the channel estimation. The sync detection is also considered. We design the training symbol to achieve a better coarse timing synchronization. Methods to suppress or circumvent the interference in the frequency estimation caused by timing errors are presented. A new performance measure for OFDM timing synchronization is proposed which leads to obtaining optimal timing estimation setting. Next, we present a joint timing synchronization, frequency synchronization and channel estimation based on training preamble based maximum likelihood realization. Further complexity reduction by an adaptive scheme is also proposed. We address some fundamental questions on peak factors, sampling theorem and sampling series. We present several bounds of bandlimited functions and peak factor ratio bound of a continuous signal and its sampled signal. Some discussion on the requirements of sampling theorems and related aspects on sampling series are presented. We study PAPR behavior of some Reed-Muller codes in OFDM systems in an attempt to find a code with good error correction, low PAPR, efficient encoding/decoding and reasonable code rate. Some regularities of the second and third-order cosets of first order Reed-Muller codes with low PAPR are presented which indicates possibility of finding such code for OFDM. The main issues in adaptive ARQ schemes are how to design the adaptive system parameters and how to effectively sense the channel conditions. We present an approach for designing the adaptive ARQ system parameters based on the through put calculation and optimization. An alternative approach which avoids the tedious throughput calculation is also presented. An effective channel sensing algorithm which utilizes the error correcting capability is proposed. Incorporation of the adaptive frequency hopping concept into the ARQ scheme with adaptive error control is introduced which has a significant throughput improvement in slow fading channels. / Graduate

Channel diversity techniques are effective ways to combat channel fading and noise in communication systems. In this thesis, I compare the performance of source and channel diversity techniques on fading and symmetric continuous channels. My experiments suggest that when SNR is low, channel diversity performs better, and when SNR is high, source diversity shows better performance than channel diversity.

The growth of broadband Internet access has paved the way for the development of many newer existing technologies. As the costs of implementing broadband access soar, the best alternative will be to use wireless technologies. At a carrier frequency of about 28 GHz, the potential benefits of Local Multipoint Distribution Service (LMDS) will eventually outweigh those of its current competitors in the wired market. Since the rural communities will reap the most benefits from this technology due to its low costs, studies on the channel behavior and terrain relationships must be done. This thesis aims to provide a preliminary study on the effects of propagating an LMDS signal over a lake surface. Currently, there is not enough information to prove the feasibility of deploying an LMDS system for this terrain. Some background on the technology and rough surface theory is provided for the reader to better understand the environment that is being investigated. Simulation results are presented as a guide to assist future researchers to conduct a field measurement campaign. A block diagram of a potential measurement system is also provided to aid in the development of the tools necessary for the measurement of an actual channel. / Master of Science

No description available.

No description available.