Sharif Digital Repository

Today, global on-chip communications become a critical power bottle-neck in high-performance many-core architectures. The importance of power dissipation in NoCs along with power reduction capability of on-chip optical interconnects offers optical network-onchip (ONoC) as a novel technology solution which can introduce on-chip interconnection architecture with high transmission capacity and low power consumption. However, the basic elements that are used in ONoCs are very temperature-sensitive. This may lead to changes in their physical characteristics which will cause incorrectness in network’s functionality. In this thesis, we propose an approach that even the elements change physically... 

MIMO radar is a next generation radar which transmits arbitrary waveforms at each one of its apertures. It has been shown that design of waveforms for MIMO radars in order to synthesize a desired spatial beampattern, is mapped into a waveform correlation matrix (R) design in the narrowband case. Therefore, waveform design in MIMO radar for beamforming could be broken into two steps, namely correlation matrix design and waveform synthesis for achieving given R. As of now, given a desired beampattern or estimated location information of targets, calculating R has been modeled as an optimization problem like SDP. Also, in some special cases like rectangular beampattern, close form solutions for... 

Nowadays, swift development of cellular network with the increased penetration rate, have made mobile voice channels widely available almost everywhere with higher priority comparing to the other conventional channels, e.g., GPRS, EDGE, HSDPA and etc. Leveraging on this fact two important utilization can be considered. The first one is related to urgent transmitting of vital data. As mentioned earlier, since this channel deems to be available everywhere and, recalling its priority, it is even accessible in congestion condition, it can be exploited as an efficient way to transmit small volume of emergence data urgently. Transforming the crash data on the road is an example of utilizing such... 

Localization of radio, acoustic and vibration wave’s sources by passive systems has many applications in positioning systems, navigation systems, wireless sensor networks, defense, security, and geophysics. RSS, AOA, TDOA, and FDOA are some of the techniques available for passive localization. The performance of TDOA/FDOA techniques does not degrade with distance and multipath, but it may suffer from poor performance for narrowband signals. On the other hand, FDOA technique requires narrowband signals. Thus, the combination of TDOA and FDOA can be suitable for a much wider range of sources. In addition, the TDOA/FDOA method can provide more accurate interference source localization compared... 

Passive wideband reconnaissance receivers, listen to the radio and radar signals in the environment and estimate their important parameters such as direction of arrival (DOA). The wideband attribute for these receivers is to refer to their ability to receive wideband signals.Due to the use of processing gain, LPI radars reduce their transmitted signal power to see and not to be seen. On the other hand reconnaissance receivers can not have much processing gain, because they do not know the nature of the transmitted signal; Therefore, to increase the operational range of these systems, it is necessary to increase the signal to noise power ratio (SNR). This thesis examines the use of antenna... 

Target localization using positioning systems has long been considered by researchers in various fields.One of the important issues in localizing a target is the accuracy of its determined position. There are several parameters in the accuracy of position estimation. In a comprehensive view, these parameters can be divided into three general factors,including the relative geometry of the transmitters/receivers with respect to the target, the accuracy of measurements, and the type of target position estimator.The first factor, i.e. the relative geometry between the target and the transmit/receive antennas, plays an important role in localization accuracy. In the first part of this thesis, the... 

Nowadays, humans can travel long distances using land, air, and sea vehicles, moving from a certain origin to a desired destination. To navigate optimally and accurately, appropriate positioning methods need to be employed, which require accurate measurements of speed, acceleration, and movement angles throughout the journey. In everyday applications, nearly all inhabitants of the Earth utilize satellite positioning methods, which are easy to use and provide adequate accuracy. However, in specific scenarios for exploratory and military applications, the use of satellite localization is not feasible. The underwater scenario is one such case, where specific measurements must be taken using... 

This study presents a non-contact heart rate monitoring system using a rotating radar system. Vital signals from individuals are detected through radar, influenced by a distance and the antenna gain-proportionality factor. In the proposed method, the number of individuals within the radar range is first estimated based on Power Spectral Density (PSD) analysis. Using Independent Component Analysis (ICA), individual signals are extracted from the mixture composed of the linear combination of signals affected by the Doppler shift. The method uses a Constant False Alarm Rate (CFAR) threshold on the PSD, enabling simultaneous heart rate monitoring for multiple persons. Additionally, a... 

In-fiber and all-optical wavelength-selective signal processing are key aspects of fiber Bragg grating (FBG)-based devices in optical communication systems. FBGs with sharp filtering properties have already been used in fiber optic communication networks as dispersion compensators, optical add–drop multiplexers, fiber lasers, and optical label switching modules. We have developed an in-fiber wavelength-selective optical intensity modulator to superimpose low rate overhead data on the transit high-speed payload signals. The tunable fiber Bragg grating (FBG), as the heart of a wavelength-selective modulator (WSM), is designed and properly biased to implement the desired modulation...