Benchmarking Wireless Network Protocols: Threat and Challenge Analysis of the AeroRP

To accommodate the unique conditions of mobile wireless networks, numerous protocols have been designed. Protocols are initially tested through simulation software, but often under non-realistic conditions, using simple or even ideal wireless environments not usually found in the real world. Without challenges and channel impairments, such simulations cannot accurately determine the advantages and disadvantages of the protocol nor can a reliable comparison be made between the performance of any two protocols. New protocols must be tested in a manner consistent with legacy protocols so they can be accurately compared and improved upon. The contributions of this thesis are a set of models that can create more realistic and challenging simulations, including a 3-D implementation of the Gauss-Markov mobility model, and a set of benchmarks that can be used to test the strengths and weaknesses of wireless routing protocols. These benchmarks are then applied to several MANET protocols including AODV, DSR, OLSR, DSDV, and AeroRP that is part of the Aero protocol stack developed at The University of Kansas. AeroRP outperforms the traditional MANET routing protocols in benchmarks that involve either highly-dynamic networks or disruptions in connectivity

Quantized vs. Analog Feedback for the MIMO Downlink: A Comparison between Zero-Forcing Based Achievable Rates

We consider a MIMO fading broadcast channel and compare the achievable ergodic rates when the channel state information at the transmitter is provided by analog noisy feedback or by quantized (digital) feedback. The superiority of digital feedback is shown, with perfect or imperfect CSIR, whenever the number of feedback channel uses per channel coefficient is larger than 1. Also, we show that by proper design of the digital feedback link, errors in the feedback have a minor effect even by using very simple uncoded modulation. Finally, we show that analog feedback achieves a fraction 1 - 2F of the optimal multiplexing gain even in the presence of a feedback delay, when the fading belongs to the class of Doppler processes with normalized maximum Doppler frequency shift 0 <= F <= 1/2.Comment: Submitted to ISIT, January 2007. 5 page

Discrete event simulation of wireless cellular networks

Postprint (published version

Algorithm for Optimizing Packet Size in Mobile Ad Hoc Networks

This thesis proposes an algorithm to optimize packet size in mobile ad hoc networks (MANET). In this thesis, the packet size is adapted to maximize the communication performance through the automatic repeat request (ARQ) protocol. The optimal packet size is chosen by an algorithm based on the estimation of the channel from the number of retransmission requests and the link statistics obtained from the mobility pattern. By adapting the non-uniform distribution of the bit error rate (BER) obtained from the mobility pattern analysis, it is possible to estimate channel conditions more accurately from the number of retransmission requests and to improve the system performance. It was found that the distribution of the link distance among mobile nodes following the Gauss-Markov mobility pattern in a circularly shaped area well fits the Beta distribution function. From the simulation results it is observed that when the interference increases, or the path loss exponent increases, or when the size of history decreases, the throughput and efficiency performance will decrease. Based on an analysis in various wireless environments, the algorithm proposed in this thesis shows almost an optimal throughput efficiency performance, and it gives better performance than the algorithm in [6], which uses an uniform distribution function for the estimation of the channel condition. By adapting the Beta distribution of the BER obtained from the mobility pattern, it is possible to estimate the channel conditions more accurately from the number of retransmission requests and to improve the throughput and utilization performance of MANET communication systems.School of Electrical & Computer Engineerin

Impacts of Mobility Models on RPL-Based Mobile IoT Infrastructures: An Evaluative Comparison and Survey

With the widespread use of IoT applications and the increasing trend in the number of connected smart devices, the concept of routing has become very challenging. In this regard, the IPv6 Routing Protocol for Low-power and Lossy Networks (PRL) was standardized to be adopted in IoT networks. Nevertheless, while mobile IoT domains have gained significant popularity in recent years, since RPL was fundamentally designed for stationary IoT applications, it could not well adjust with the dynamic fluctuations in mobile applications. While there have been a number of studies on tuning RPL for mobile IoT applications, but still there is a high demand for more efforts to reach a standard version of this protocol for such applications. Accordingly, in this survey, we try to conduct a precise and comprehensive experimental study on the impact of various mobility models on the performance of a mobility-aware RPL to help this process. In this regard, a complete and scrutinized survey of the mobility models has been presented to be able to fairly justify and compare the outcome results. A significant set of evaluations has been conducted via precise IoT simulation tools to monitor and compare the performance of the network and its IoT devices in mobile RPL-based IoT applications under the presence of different mobility models from different perspectives including power consumption, reliability, latency, and control packet overhead. This will pave the way for researchers in both academia and industry to be able to compare the impact of various mobility models on the functionality of RPL, and consequently to design and implement application-specific and even a standard version of this protocol, which is capable of being employed in mobile IoT applications