On the Convergence of Blockchain and Internet of Things (IoT) Technologies

The Internet of Things (IoT) technology will soon become an integral part of our daily lives to facilitate the control and monitoring of processes and objects and revolutionize the ways that human interacts with the physical world. For all features of IoT to become fully functional in practice, there are several obstacles on the way to be surmounted and critical challenges to be addressed. These include, but are not limited to cybersecurity, data privacy, energy consumption, and scalability. The Blockchain decentralized nature and its multi-faceted procedures offer a useful mechanism to tackle several of these IoT challenges. However, applying the Blockchain protocols to IoT without considering their tremendous computational loads, delays, and bandwidth overhead can let to a new set of problems. This review evaluates some of the main challenges we face in the integration of Blockchain and IoT technologies and provides insights and high-level solutions that can potentially handle the shortcomings and constraints of both IoT and Blockchain technologies.Comment: Includes 11 Pages, 3 Figures, To publish in Journal of Strategic Innovation and Sustainability for issue JSIS 14(1

Optimal Complex-Valued Prototype Filter Design for GFDM Systems

One of the main challenges with generalized frequency division multiplexing (GFDM) systems is prototype filter design. A poorly designed filter increases inherent and out-of-band (OOB) interferences. In this paper, we introduce a novel optimal prototype filter for GFDM systems that eliminates the negative effects of intrinsic interferences. We introduce a complex-valued pulse shape similar to a single-sideband (SSB) modulation scheme, which significantly improves bandwidth efficiency. Specifically, we introduce an optimization problem to design an optimal pulse shape filter to reduce all intrinsic interference to zero. We derive analytical expressions to evaluate the bit error rate (BER) of the system and show how the designed optimal prototype filter outperforms its current counterparts.Comment: arXiv admin note: text overlap with arXiv:2301.1047

Performance of MIMO space-time coded system and training based channel estimation for MIMO-OFDM system

Multiple-input-multiple-output (MIMO) antenna architecture has the ability to increase capacity and reliability of a wireless communication system. Orthogonal frequency division multiplexing (OFDM) is another popular technique in wireless communication which is famous for the efficient high speed transmission and robustness to frequency selective channels. Therefore, the integration of the two technologies probably has the potential to meet the ever growing demands of future communication systems. Because of aforementioned merits of these two techniques, this thesis was about MIMO and MIMO-OFDM system, and it addressed two different issues. Firstly it has investigated the performance of MIMO-STBC system and surveyed the effect of imperfect channel estimation on performance of MIMO-OFDM system. Secondly, it has focused on training based channel estimation algorithm for MIMO-OFDM system. In the first part, BER of space-time block coded system (STBC) was calculated for different antenna configuration using simulation software. The results proved that the reliability of the wireless link increases as the number of transmits and received antenna increase. At the next stage of the project, the effect of channel estimation algorithm on performance of MIMO-OFDM system was investigated. The simulation results shown that imperfect channel estimation degrade the performance of the system significantly. At the final part of the research, channel estimation in MIMO-OFDM system has been discussed. The mathematical model of the system in frequency selective fading channel has been developed. Then the comparison analysis in terms of performance efficiency and computational complexity has been made for two different channel estimations algorithm namely LS (Least Square) and QR decomposition. It should be mentioned that reduction of computational complexity of the channel estimation and data detection algorithm is a major challenge for receiver design in MIMO-OFDM system, and complication of receiver design is mostly due to these algorithms. Therefore in this part QR decomposition algorithm has been investigated as a solution. For doing so, the performance analysis between QR decomposition and LS algorithm in terms of MSE (Mean Square Error) and BER (Bit Error Rate) has been done using simulations software. A complexity comparison between two algorithms has been made in terms of number of mathematical operation. The results have shown that the performance efficiency of these two algorithms are exactly the same as it expected while the computational complexity of the QRD is much less than LS algorithm. Finally it can be concluded that the application of QR decomposition can greatly reduces the complexity of channel estimation in MIMO-OFDM syste

Antenna design using left-handed materials

Smart antenna technologies are emerging as an innovative way to meet the growing demand for more powerful, cost-effective and highly efficient wireless communication systems. In this project, from broad category of smart antenna techniques, the switch beam digital-beamforming technique in the downlink is deployed to improve the fidelity and performance of WiMax application. In this regards, the designed system forms and steer the beam according to the user location which is known to the system. In addition, the system performs sidelobe cancellation base on the chebyshev algorithm to optimize the antenna radiation pattern. The design and implementation steps are as follow: the system is firstly modeled by MATLAB software. After modeling, the algorithm is implemented in DSP by using C and Code Composer Studio. After DSP hardware implementation, the signal management is performed in DSP before transmission to the FPGA board. This management is necessary, in order to make processed signal in DSP suitable for channel separation process in FPGA. FPGA is deployed to split the data stream into sixteen channels corresponding to number of antenna elements. Next, the FPGA and DSP are integrated together to form the baseband switch beam smart antenna system. After integration process, the hardware is tested; the results prove that the system functions properly as we expected from simulation model. In this project, lastly, the initial design of IF, RF-front-end and their necessary circuits are also portrayed to be used in the next smart antenna research project

Computational complexity reduction for MIMO-OFDM channel estimation algorithms

Channel estimation algorithms have a key role in signal detection in MIMO-OFDM systems. In this system, the number of channel components which need to be estimated is much more than conventional SISO wireless systems. Consequently, the computational process of channel estimation is highly intensive. In addition, the high performance channel estimation algorithms mostly suffer from high computational complexity. In the other words, the system undergoes intensive computations if high performance efficiency is desired. However, there is an alternative solution to achieve both high performance efficiency and relatively low level of computational complexity. In this solution, high efficient channel estimation is firstly designed, and then it is simplified using alternative mathematical expressions. In this research, QR decomposition (QRD) as an alternative mathematical expression to alleviate the computational complexity of those complex algorithms which need matrix inversion is investigated. Herein, the channel estimation algorithm which is targeted to simplify is Least Square (LS) method. The results show QR decomposition can greatly reduce the complexity of LS channel estimation. As an example, for particular scenario, it achieves reduction of computational complexity as much as 77% while it keeps the performance efficiency of the system at the same level