Mohamed E Saad

University of Sharjah | US · Department of Electrical and Computer Engineering

Ambient backscatter communication (AmBC) is a highly promising technology that enables the ubiquitous deployment of low-cost, low-power devices to support the next generation of Internet-of-Things (IoT) applications. This paper addresses channel estimation for full-duplex multi-antenna AmBC systems. This is highly challenging due to the large numbe...

Recognition of the modulation scheme is the intermediate step between signal detection and demodulation of the received signal in communication networks. Automatic modulation recognition (AMR) plays a central role in many applications, especially in the military and security sectors. In general, several properties of the received signal are extract...

With the advent of fifth generation (5G) systems and the Internet-of-Things (IoT), the number of interconnected wireless devices is increasing significantly. Protocols that allow these deceives to interconnect peer-to-peer through wireless links are becoming of interest. The major challenge is the inevitable interference among the simultaneously ac...

In this work, we consider amplify-and-forward two-way relay networks operating under the imperfect conditions of in-phase and quadrature-phase (I/Q) imbalance. We propose novel, efficient solutions for the problem of joint channel and I/Q imbalance estimation and the related problem of optimal pilot design. Three different estimation algorithms are...

Abstract This paper considers the problem of joint timing‐offset and channel estimation for physical‐layer network coding systems operating in frequency‐selective environments. Three different algorithms are investigated for the joint estimation of the channel coefficients and the fractional timing offset. The first algorithm is based on the maximu...

This paper explores the problem of energy-efficient shortest path planning on off-road, natural, real-life terrain for unmanned ground vehicles (UGVs). We present a greedy path planning algorithm based on a composite metric routing approach that combines the energy consumption and distance of the path. In our work, we consider the Terramechanics be...

Ambient backscatter communication systems (ABCSs) have been gaining popularity as a green alternative to conventional communication systems. To deploy such systems, it is important to acquire the channel state information (CSI) and to account for hardware imperfections such as carrier-frequency offsets (CFOs) and inphase/quadrature (I/Q) imbalance....

The problem of finding the route with maximum end-to-end spectral efficiency in a multihop wireless network has been subject to considerable interest in the recent literature. It has been established that the problem is polynomially solvable in networks that employ time division multiple access (TDMA) or frequency division multiple access (FDMA). T...

The fifth generation of wireless networks (5G) will kick off with evolved mobile broadband services as promised by several mobile-related associations, researchers, and operators. Compared to 4G, 5G aims to provide greater data rates with lower latency and higher coverage to numerous users who stream ubiquitous multimedia services. 5G benefits the...

In cellular networks, users near the edge of the cell are usually suffering from low signal-to-noise-plus-interference-ratio (SINR) levels as a result from being far away from the base-station (BS). Many factors could lead to huge attenuation of the received signal in the cell-edge area such as path-loss and multipath fading. Increasing the BS tran...

The cloud radio access network (C-RAN) aims at migrating the traditional base station functionality to a cloud-based centralized base band unit (BBU) pool, thereby providing a promising paradigm for fifth-generation (5G) wireless systems. This results in a novel wireless architecture in which mobile users communicate with the cloud via distributed...

n this paper, we consider the problem of joint timing-offset and channel estimation for amplify-and-forward (AF) two-way relay networks (TWRNs). This problem is solved for generic pulse-shaping filters, taking into account the filter truncation in practical communication and considering both pilot-based and semi-blind estimation strategies. Beginni...

Heterogeneous networks that consist of densely deployed base stations of different (macro and small-cell) tiers are envisioned to be among the key technologies for providing the high data rates required in 5G systems. Moreover, interconnecting small-cell base stations via millimeter-wave (mm-wave) backhaul links is a flexible and cost-effective alt...

This work considers the problem of joint channel and carrier frequency offset (CFO) estimation for asynchronous amplify-and-forward (AF) two-way relay networks (TWRNs). This problem has not been solved to the best of our knowledge, and the presence of timing offsets between the two terminals, in addition to the frequency offsets, makes it necessary...

Delays caused by congestion, faults and process variation (PV) degrade networks-on-chip (NoC) performance. A congestion aware, fault tolerant and process variation aware adaptive routing algorithm (CFPA) is introduced for congested and faulty asynchronous NoCs. The proposed routing algorithm maintains two routing tables to determine the packet path...

It is a well-established fact that routing metrics cannot be optimized via shortest path algorithms unless they are both monotone and isotonic. In particular, monotonicity guarantees the convergence of the shortest path procedure, while isotonicity guarantees convergence to the optimal path. This paper presents a class of routing metrics that are n...

Finding the route with maximum end-to-end spectral efficiency in multihop wireless networks has been subject to interest in the recent literature. All previous studies, however, focused on finding one route from a given source to a given destination under the constraint of equal bandwidth sharing. To the best of our knowledge, for the first time, t...

Finding the optimal path in multi-hop wireless networks has gained considerable interest in the recent literature. Standard routing methods such as Ad-hoc On-Demand Distance Vector Routing (AODV) and Dynamic Source Routing (DSR) are based on link-level abstraction of the network without fully considering the impact of the physical layer. Recent stu...

Given a multihop wireless network and a source-destination pair of nodes, this paper addresses the problem of jointly selecting a communication route and allocating transmit power levels, so that the end-to-end spectral efficiency of the route exceeds a desired threshold. Spectral-efficient routing has been subject to interest in the recent literat...

In this paper, we consider a network-coded cooperative wireless network, where users mutually pair among themselves to realize network coding. We assume a multi-user environment, where users transmit to a common destination in the absence of dedicated relaying nodes. We address the important problem of the mutual pairing of users, which directly go...

Given a multihop wireless network and a source-destination pair of nodes, this paper addresses the problem of jointly selecting a communication route and allocating transmit power levels, so that the end-to-end spectral efficiency of the route exceeds a desired threshold and the maximum power used by any link is minimized. Spectral-efficient routin...

This paper addresses the problem of finding the route with maximum end-to-end spectral efficiency, under the constraint of equal bandwidth sharing, in multihop wireless networks that use time division multiple access (TDMA) or frequency division multiple access (FDMA). The conceptual difficulty of this problem arises from the fact that the associat...

In this paper, we consider a network-coded cooperative wireless network, where users mutually pair among themselves to realize network coding. We consider a multi-user environment, where users transmit to a common destination, without engaging the idle users into cooperation. Two nodes constituting a pair periodically swap the roles of source and r...

This paper addresses the problem of joint admission and power control in the downlink of a single-cell code-division-multiple-access (CDMA) wireless network. The objective is to maximize the user-capacity (or base station revenue), while meeting the quality-of-service (QoS) requirements of each admitted user. This paper considers bounded maximum de...

Given a multihop cellular network with fixed relays, this paper considers the problem of jointly selecting (possibly multiple) routing paths for each communication session and allocating transmit powers and bandwidth across all network links, such that the total network utility (i.e., social welfare) is maximized. This paper focuses on quality of s...

Applications in ubiquitous computing environments are expected to have different priorities, memory and real-time requirements. Given a home gateway with a set of running services, we need to terminate some of the existing services to allow a more important service to start. This paper presents heuristics for service replacement that try to termina...

This paper addresses the problem of finding the route with maximum end-to-end spectral efficiency, under the constraint of equal bandwidth sharing, in multihop wireless networks that use time division multiple access (TDMA). The difficulty of this problem arises from the fact that the associated routing metric is neither isotonic nor monotone, and,...

This paper addresses the problem of finding the route with maximum end-to-end spectral efficiency, under the constraint of equal bandwidth sharing, in multihop wireless networks. This problem has been addressed recently in the literature, and only exhaustive search with exponential computational complexity or suboptimal heuristics are known. This p...

Given a multilayer routing area, we consider the global routing problem of selecting a maximum set of nets, such that every net can be routed entirely in one of the given layers without violating the physical capacity constraints. This problem is motivated by applications in multilayer IC and multichip module (MCM) layout designs. The contribution...

This paper addresses the problem of joint admission control and power allocation in the downlink of a single-cell code-division-multiple-access (CDMA) wireless network. The objective is to maximize the user-capacity (or base station revenue), while meeting the strict quality-of-service (QoS) requirements of each admitted user. We prove that the glo...

Particle Swarm Optimization (PSO) is a heuristic search method for the exploration of solution spaces of complex optimization problems. The heuristic suffers from relatively long execution times as the update step needs to be repeated many thousands of iterations to converge the swarm on the global optimum. In this work, we explore two dynamic popu...

Given a multihop cellular network with fixed relays, this paper considers the problem of jointly selecting (possibly multiple) routing paths for each communication session and allocating transmit powers and bandwidth across all network links, such that the total network utility (i.e., social welfare) is maximized. This paper focuses on quality of s...

We address the problem of allocating transmission rates to a set of network sessions with end-to-end bandwidth and delay requirements. We give a unified convex programming formulation that captures both average and probabilistic delay requirements. Moreover, we present a distributed algorithm and establish its convergence to the global optimum of t...

This paper addresses the problem of joint routing and radio resource management in multihop cellular networks with fixed relays. The objective is to maximize the total network utility. This paper focuses on quality of service (QoS-) sensitive applications that are captured by sigmoidal-like utility functions. The non-concavity of the user utility f...

We address the problem of allocating transmission rates to a set of network sessions with end-to-end bandwidth and delay requirements. We give a unified convex programming formulation that captures both average and probabilistic delay requirements. Moreover, we present a distributed algorithm and establish its convergence to the global optimum of t...

Given a collection of lightpath requests, we consider the problem of allocating fibers to the links of a WDM network at minimum cost, such that all lightpath requests can be simultaneously realized. It is known that, under modular fiber capacity assumptions, shortest path routing may not minimize the total fiber cost. In this paper, we extend our p...

We address the problem of allocating transmission rates to a set of network sessions with end-to-end bandwidth and delay requirements. We give a unified convex programming formulation that captures both average and probabilistic delay requirements. Moreover, we present a distributed algorithm and establish its convergence to the global optimum of t...

Given a combination of unprotected and dedicated edge-disjoint path (1+1) protected connection requests and a finite set of fiber types, we consider the problem of allocating fibers on the links of a WDM network at minimum cost, such that all connection requests can be simultaneously realized. Each fiber type, is characterized by its capacity and i...

Given an undirected edge-capacitated graph and given (possibly) different subsets of vertices, we consider the problem of selecting a maximum (weighted) set of Steiner trees, each tree spanning a subset of vertices, without violating the capacity constraints. This problem is motivated by applications in multicast communication networks. We give an...

In a wavelength division multiplexing (WDM)-based network, lightpaths are established between router pairs to form a virtual topology residing on top of the underlying physical topology. The ability to reconfigure its virtual topology upon dynamically changing traffic patterns has been identified as one of the most important features of WDM-based n...

This paper addresses the problem of routing and wavelength assignment (RWA) in multifiber WDM networks with limited resources. Given a traffic matrix, the number of fibers per link, and the number of wavelengths a fiber can support, we seek to maximize the carried traffic of connections. We formulate the problem as an integer linear program (ILP),...

We address the problem of allocating fibers (each supporting only a limited set of wavelengths) on the links of a WDM network at minimum cost, such that a set of edge-disjoint path protected connection requests can be realized. The cost of a link is assumed to be linear in the number of fibers rather than being linear in the number of wavelengths u...

In a WDM based network, lightpaths are established between router pairs to form a virtual topology residing on top of the underlying physical topology. The ability to reconfigure its virtual topology upon dynamically changing traffic patterns has been identified as one of the most important features of WDM based networks. Compared to previously rep...

This paper addresses the problem of routing and wavelength assignment (RWA) in multifiber WDM networks assuming neither a special topology nor wavelength converters. Given a set of connection requests, the number of fibers deployed on each link, and the number of wavelengths a fiber can support, we seek to maximize the number of lightpaths that can...