Futuristic requirements of mobile communication systems ask for discovering new possibilities and dimensions to enable ultrafast and reliable communication. This work relates to the advancements in jointly decoded iterative multimedia communication systems for the H.264 source standard. The beneficial technique of Over-Complete Mapping (OCM) is utilized for introducing redundancy in the highly compressed source encoded video streams. Differential Space–Time Spreading (DSTS) is invoked along with Rate-3/4 Recursive Systematic Convolutional (RSC) as intermediate encoder in the proposed three-stage setup. More specifically, the RSC encoder is beneficial in attaining the iterative gain as it divides the decoder into two parts. The DSTS is invoked with the Sphere Packing (SP) modulation which is highly desirable for the non-coherent detection schemes without requiring any information from the channel. The proposed system comprises of three main components, namely OCM, Rate-3/4 RSC and SP modules, thus we call this as three-stage system. The iterative decoding enhances the Bit-Error Rate (BER) and Peak Signal-to-Noise Ratio (PSNR) performances of the joint source-channel systems. Furthermore, to expeditiously predict the convergence pattern of the proposed three-stage iteratively decoded systems, EXtrinsic Information Transfer (EXIT) chart analysis is performed. Moreover, the effect of variations in the minimum Hamming distance ( $${d}_{H,min}$$ d H , m i n ) is observed for the proposed three-stage system. The $${{DSTS}-{SP}-{RSC}-{OCM}}_{[5 15]}$$ DSTS - SP - RSC - OCM [ 515 ] having $${d}_{H,min}=6$$ d H , m i n = 6 exhibits a gain of 20 dB against the benchmarker $${{DSTS}-{SP}-{RSC}-{OCM}}_{[2 6]}^{*}$$ DSTS - SP - RSC - OCM [ 26 ] ∗ with $${d}_{H,min}=1$$ d H , m i n = 1 at the PSNR degradation point of 1 dB over a correlated Rayleigh fading channel.

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

Compensation of data loss in the state estimation plays an indispensable role in efficient and stable control and communication systems. However, accurate compensation of data loss in the state estimation is extremely challenging issue. To cater this challenging issue, two techniques such as the open-loop Kalman filter and the compensating closed-loop Kalman filter have emerged. The closed-loop technique compensates for the missing data using the autoregressive model. However, the autoregressive model used only past measurements for data loss compensation. Considering only one parameter, i.e., the past measurements, is insufficient and leads to inaccurate state estimation. Thus, in this work, autoregressive moving average with exogenous inputs model considers three parameters, i.e., the past measurements, the input signal, and the sensor noise, simultaneously to compensate data loss in state estimation. To endorse the effectiveness and applicability of the proposed model, a standard mass-spring-damper is employed in the case study. Simulation results show that the proposed model outperforms the existing autoregressive models in terms of performance parameters.

Pakistan is faced with energy crises from the last two decades. Generation cannot balance the load demands of the electricity consumers. Power delivery systems are generally old-fashioned and overloaded. They are unable to provide consistent and uninterrupted supply to commercial, industrial, and domestic loads. Generally speaking, the Power Systems consist of loads that are inductive and resistive in nature. Heavy machinery, induction motors, and arc furnaces are heavily inductive in nature. Inductive loads when operated in a weak power system results in lagging VARs (Volt Ampere Reactive) and poor voltage regulation, which must be balanced by the same number of leading VARs in order to ensure unity power factor and thus helps in improving the voltage profile. At times the reactive VARs injected may not be sufficient to balance the VARs requires by the system, but still the power factor is improved up to some extent. In hot and humid climatic conditions, air-cooling system and chillers greatly burdens the grids. Such loads require excessive reactive VARs, and if not offered with ample reactive power, causes severe voltage drops in distribution system. To manage low voltages and power-factor, household users use automatic voltage regulators while industries connect capacitor banks. Voltage regulators control output voltage within the required limits at the expense of excessive line current from transformer, which may overburden it. Moreover, with each operation of tap changer, current rises which further intensifies line losses. Static capacitors provide stable voltage but repeated variations in load demands reliable and vigorous voltage regulation. This investigation aims to come up with a power quality improvement scheme which would deliver instantaneous control of power (reactive) with SVC (Static VAR Compensator) thus overcoming the shortcomings of step-wise banks of capacitors and or voltage regulators. Simulation work is carried out in MATLAB/SIMULINK and the results are compliance with IEEE Standards for SVCs. The device can offer steady state as well as dynamic VAR compensation under changing load conditions. Result showed considerable improvement both in terms of response time and power factor. Switching time has been improved to less than 1/10th fraction of a second which in previous simulations was 0.7 seconds approximately. Initial power factor without disturbance and without compensation was recorded to be 0.6 lagging, which after compensation was improved to 0.95 lagging. Similarly, in presence of disturbance without compensation the power factor fluctuated between 0.55 and 0.9 lagging, which after compensation was improved to 0.95 lagging and above throughout the course of operation.

A novel low-profile and miniaturized patch antenna on a substrate material of high dielectric constant has been designed, fabricated and tested in an indigenous laboratory. It is highly important to reduce the size of patch antenna as it limits the reduction of the sizes of the devices using this antenna. A number of techniques have been given for the size reduction of patch such as DGS (Defected Ground Structure), use of fractals and the use of metamaterials but in this paper the technique of high permittivity substrate has been implemented. The substrate as well as this conventional antenna has been prepared locally in Pakistan. A ceramic material of chemical composition {(Sr0.5Pb0.25Ca0.25)-Tio3-3Bi2O3.TiO2} having a high dielectric constant has beenused in the substrate of the antenna. The fabricated prototype was investigated experimentally for important parameters using Vector Network analyzer. The total measure of the antenna is 20.5x26.5x1.5 mm3. The antenna presented a large bandwidth of 186 MHz (1070-1256 MHz)in L-Band with a Return Loss of 21.10 dB at resonance. The VSWR (Voltage Standing Wave Ratio) remained under the standard value of 2 in the whole operating range. The proposed antenna may be employed in GPS (Global Positioning System) devices, Amateur Radio, Terrestrial Mobile Communication, Aeronautical and Maritime Mobile and other Military and Low Earth Orbit Satellite Communications.