Impact of Relay Location of STANC Bi-Directional Transmission for Future Autonomous Internet of Things Applications

Wireless communication using existing coding models poses several challenges for RF signals due to multipath scattering, rapid fluctuations in signal strength and path loss effect. Unlike existing works, this study presents a novel coding technique based on Analogue Network Coding (ANC) in conjunction with Space Time Block Coding (STBC), termed as Space Time Analogue Network Coding (STANC). STANC achieves the transmitting diversity (virtual MIMO) and supports big data networks under low transmitting power conditions. Furthermore, this study evaluates the impact of relay location on smart devices network performance in increasing interfering and scattering environments. The performance of STANC is analyzed for Internet of Things (IoT) applications in terms of Symbol Error Rate (SER) and the outage probability that are calculated using analytical derivation of expression for Moment Generating Function (MGF). In addition, the ergodic capacity is analyzed using mean and second moment. These expressions enable effective evaluation of the performance and capacity under different relay location scenario. Different fading models are used to evaluate the effect of multipath scattering and strong signal reflection. Under such unfavourable environments, the performance of STANC outperforms the conventional methods such as physical layer network coding (PNC) and ANC adopted for two way transmission

Reliable Communication in Wireless Networks

Wireless communication systems are increasingly being used in industries and infrastructures since they offer significant advantages such as cost effectiveness and scalability with respect to wired communication system. However, the broadcast feature and the unreliable links in the wireless communication system may cause more communication collisions and redundant transmissions. Consequently, guaranteeing reliable and efficient transmission in wireless communication systems has become a big challenging issue. In particular, analysis and evaluation of reliable transmission protocols in wireless sensor networks (WSNs) and radio frequency identification system (RFID) are strongly required. This thesis proposes to model, analyze and evaluate self-configuration algorithms in wireless communication systems. The objective is to propose innovative solutions for communication protocols in WSNs and RFID systems, aiming at optimizing the performance of the algorithms in terms of throughput, reliability and power consumption. The first activity focuses on communication protocols in WSNs, which have been investigated, evaluated and optimized, in order to ensure fast and reliable data transmission between sensor nodes. The second research topic addresses the interference problem in RFID systems. The target is to evaluate and develop precise models for accurately describing the interference among readers. Based on these models, new solutions for reducing collision in RFID systems have been investigated

Network Challenges of Novel Sources of Big Data

Networks and networking technologies are the key components of Big Data systems. Modern and future wireless sensor networks (WSN) act as one of the major sources of data for Big Data systems. Wireless networking technologies allow to offload the traffic generated by WSNs to the Internet access points for further delivery to the cloud storage systems. In this thesis we concentrate on the detailed analysis of the following two networking aspects of future Big Data systems: (i) efficient data collection algorithms in WSNs and (ii) wireless data delivery to the Internet access points.The performance evaluation and optimization models developed in the thesis are based on the application of probability theory, theory of stochastic processes, Markov chain theory, stochastic and integral geometries and the queuing theory.The introductory part discusses major components of Big Data systems, identify networking aspects as the subject of interest and formulates the tasks for the thesis. Further, different challenges of Big Data systems are presented in detail with several competitive architectures highlighted. After that, we proceed investigating data collection approaches in modern and future WSNs. We back up the possibility of using the proposed techniques by providing the associated performance evaluation results. We also pay attention to the process of collected data delivery to the Internet backbone access point, and demonstrate that the capacity of conventional cellular systems may not be sufficient for a set of WSN applications including both video monitoring at macro-scale and sensor data delivery from the nano/micro scales. Seeking for a wireless technology for data offloading from WSNs, we study millimeter and terahertz bands. We show there that the interference structure and signal propagation are fundamentally different due to the required use of highly directional antennas, human blocking and molecular absorption. Finally, to characterize the process of collected data transmission from a number of WSNs over the millimeter wave or terahertz backhauls we formulate and solve a queuing system with multiple auto correlated inputs and the service distribution corresponding to the transmission time over a wireless channel with hybrid automatic repeat request mechanism taken into account

A testbed for MANETs: Implementation, experiences and learned lessons

In this paper, we present the implementation, experiences and lessons learned of our tesbed for Ad-hoc networks and Mobile Ad hoc Networks (MANETs). We used OLSR protocol for real experimental evaluation. We investigate the effect of mobility and topology changing in the throughput of a MANET. We study the impact of best-effort traffic for Mesh Topology and Linear Topology. In this work, we consider eight experimental models and we assess the performance of our testbed in terms of throughput, round trip time and packet loss. We found that some of the OLSR's problems can be solved, for instance the routing loop, but this protocol still has the self-interference problem. Also, there is an intricate interdependence between MAC layer and routing layer. We carried out the experiments considering stationary nodes of an Ad-hoc network and the node mobility of MANETs. We found that throughput of TCP was improved by reducing Link Quality Window Size (LQWS). For TCP data flow, we got better results when the LQWS value was 10. Moreover, we found that the node join and leave operations increase the packet loss. The OLSR protocol has a good performance when the source node is moving. However, the performance is not good when the relay nodes are moving.Peer ReviewedPostprint (published version