There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

http://ieeexplore.ieee.org/iel5/3/23094/01073023.pdf

Statistical optics

Several simplified design procedures for solar energy systems require monthly average meteorological data. Monthly average daily totals of the solar radiation incident on a horizontal surface are available. However, radiation data on tilted surfaces, required by the design procedures, are generally not available. A simple method of estimating the average daily radiation for each calendar month on surfaces facing directly towards the equator has been presented by Liu and Jordan [1]. This method is verified with experimental measurements and extended to allow calculation of monthly average radiation on surfaces of a wide range of orientations.

Calculation of monthly average insolation on tilted surfaces

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

/pdf/response-to-fcc-98-208-notice-of-inquiry-in-the-matter-of-3attixctl7.pdf

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

Ultra Wideband Signals and Systems in Communication Engineering

Recently, many literatures were presented to mitigate the noises or to suppress inter-symbol interference (ISI) and inter-frame interference (IFI) with systems operate in time hopping spread spectrum. The structure of the conventional rake-receiver is more complex that based on large number of multiple paths in wireless ultra wideband (UWB) communication systems. In this paper we proposed low complexity of rake-receiver that includes four fingers with additional finger used to support the outputs of other fingers by comparison process. This design is called multiple comparators rake-receiver. Low complexity receiver of maximum ratio combining (MRC) technique was simulated with perfect channel estimation. From simulation results, the optimized performance of the proposed scheme is presented by reducing the bit error rate (BER) with respect to conventional rake-receiver.

UWB selective rake receiver using multiple comparators

This paper investigates the avalanche photodiode (APD) gain effect on spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) system using a modified-AND subtraction detection in comparison to the conventional AND detection scheme. Analytical results are presented to investigate the APD gain impact on the bit-error rate (BER) performance. In addition, we confirm the influence of the APD over the positive-intrinsic-negative (PIN) photodiode on the system performance using data transmission simulations.

APD gain effect on SAC-OCDMA system using modified-and detection technique

This paper discusses the enhancement of the wireless rake receiver for high speed and short distance indoor ultra wideband (UWB) propagation with line-of sight (LOS) and non line-of sight (NLOS) channel models. The proposed matched rake receiver uses three main combining techniques, maximum ratio combining (MRC), equal gain combining (EGC), and selective combining (SC) to capture most of the energy of the multi-path components (MPCs). When the wireless communication systems work with high capacity and high speed in transmission and reception scenarios, there will be a serious challenge defined as inter-symbol interference (ISI) during the reception process. The ISI causes increasing in the bit error rate (BER) when the wireless communication systems work with high bit rate propagation. The matched rake receiver scheme was designed to suppress ISI by maximizing the signal to noise ratio (SNR) before constructing the desired signal in decision circuit and effectively the system enhancement is improved. After adding additive white Gaussian noise (AWGN) to the received signal, the improvement is cleared comparing with the theoretical results that has no AWGN. During the comparison of the simulation results, MRC partial rake receiver of less complexity showed better performance than the EGC and SC rake receivers.

Performance Evaluation of Adaptive Indoor Matched Rake Receiver Using Multiple-Combining Techniques

Optical OFDM system is considered to be the essential backbone of the next generation of ultra-high-speed networks. A dispersion effect is considered one of the common limitations in optical OFDMA system especially at very high date rate. When the pulse width reaches less than a few pico-seconds, not only the second-order but even higher-order dispersion must be taken into account. In this paper OOFDM system designed with traditional dispersion compensating devices such as Dispersion compensating fiber (DCF) used in multi spans with single mode fiber to reach to 288 km distance at 20 Gb/s. moreover, single side band (SSB) used to reduce the dispersion as well. Therefore, the overall system performance based on SNR, spectral analyzer and constellation diagram for the single side band (SSB) OOFDM system gives a good result with 16 QAM modulation.

20 Gb/s optical OFDM transmission for long haul transmission

The scattering and reflections that occur-during indoor propagation create serious problems for multi-path channel transmissions due to seriously suffering from plenty of resolvable multipath components (MPCs) through line of sight (LOS) and non-line of sight (NLOS) environments. This high-gain antenna can be used to evaluate indoor, single-in single-out (SISO) and multiple-in multiple-out (MIMO) UWB systems. The high-gain antenna gives a more powerful link that can transmit and receive more data at a faster rate while mitigating interference. The capacities of the channels for these wireless systems and the advantages of using multiple antennas rather than a single antenna are presented.

Hilal A. Fadhil

Papers

UWB selective rake receiver using multiple comparators

APD gain effect on SAC-OCDMA system using modified-and detection technique

Performance Evaluation of Adaptive Indoor Matched Rake Receiver Using Multiple-Combining Techniques

20 Gb/s optical OFDM transmission for long haul transmission

Improving the capacity of channels for multi-path, indoor, ultra-wideband wireless systems