Papers by Sahibzada Ali Mahmud
IEEE Power & Energy Magazine, 2012
Looking at the communication industry, one observes how drastically the communication horizon has... more Looking at the communication industry, one observes how drastically the communication horizon has changed. From letters to e-mails and SMS, from phone calls to video chat and live conferencing, from phone booths to smart phones: since the digitization of communication, a new era of consumer choice has been inaugurated. The potential exists for similar transformation and opportunity in the provision of electricity, embodied in a concept known as the “smart grid”. Smart grid is the electric delivery network from electrical generation to the end user that makes use of the latest advances in wireless communication and intelligent information management systems to ameliorate the electric system robustness, reliability, efficiency, and security. Like the telecommunications and the genesis of the Internet, technology holds the key to the smart grid and its realization.
Mobile ad hoc networks (MANETs) are rapidly evolving and the notion of ad hoc networking has beco... more Mobile ad hoc networks (MANETs) are rapidly evolving and the notion of ad hoc networking has become one of the most challenging research areas of wireless communications. The rising popularity of real-time applications among end users in MANETs has stimulated a surge of research in routing and providing quality of service (QoS) support in such networks. Capacity estimation is a
Abstract An ever-growing demand for higher data-rates and coverage extension has motivated the in... more Abstract An ever-growing demand for higher data-rates and coverage extension has motivated the interconnection of mobile ad-hoc networks to fixed IP networks, to form a Hybrid Wireless Network (HWN). The convergence of ad-hoc and infrastructure network is ...
A fast learning neuro-evolutionary technique that evolves Artificial Neural Networks using Cartes... more A fast learning neuro-evolutionary technique that evolves Artificial Neural Networks using Cartesian Genetic Programming (CGPANN) is used to detect the presence of breast cancer. Features from breast mass are extracted using fine needle aspiration (FNA) and are applied to the CGPANN for diagnosis of breast cancer. FNA data is obtained from the Wisconsin Diagnostic Breast Cancer website and is used for training and testing the network. The developed system produces fast and accurate results when compared to contemporary work done in the field. The error of the model comes out to be as low as 1% for Type-I (classifying benign sample falsely as malignant) and 0.5% for Type-II (classifying malignant sample falsely as benign).
The idea of mass deployment of an Advanced Metering Infrastructure (AMI) for Smart Grids has been... more The idea of mass deployment of an Advanced Metering Infrastructure (AMI) for Smart Grids has been explored and evaluated in this paper. Since smart meters with a wireless interface that can connect to the utility provider's server via a backhaul network forms the basic building block of an AMI, it is a good paradigm for an M2M application in Smart Grids. The relevant standardization efforts by 3GPP and ETSI are discussed along with other perceived application scenarios for M2M communication. An example architecture is then proposed and evaluated with clusters of smart meters that transfer their data via UMTS network to a server. The performance evaluation is carried out considering network throughput, latency, and the data generated by the smart meters using both TCP and UDP traffic. The results indicate that there is a substantial reduction in delay when UDP traffic is considered when compared to TCP traffic generated by the smart meters.
High data rate wireless personal area networks (WPANs) operate in a limited space with emphasis o... more High data rate wireless personal area networks (WPANs) operate in a limited space with emphasis on supporting multimedia applications. The requirements for different types of voice and video codecs vary and therefore the resource allocation should be done accordingly. The efficient utilization of high data rate WPAN superframe is determined by the number of devices and the channel time allocated
Wireless Mesh Networks (WMNs) is a promising technology for backhaul wireless connectivity in use... more Wireless Mesh Networks (WMNs) is a promising technology for backhaul wireless connectivity in user premises due to its multi-hop nature, multi-radio multi-channel capabilities and stable power supplies. With proliferation of new and advanced access technologies, future WMN's will bean integrated paradigm to provide seamless and ubiquitous connectivity to multi interface end user devices. Co-existence of multiple heterogeneous interfaces on wireless mesh routers increases overall network capacity, resilience and availability in the mesh backhaul as compared to homogenous radios mesh networks. In this paper, we present a novel architecture for heterogeneous WMN's based on integrated IEEE 802.11/16/15 technologies and discuss issues, possible solutions and future insight. We propose an optimal route algorithm along with radio assignment graph which captures the heterogeneity of radios. We also present a handover mechanism for seamless interface switch for mobile and static end user devices.
In the past a lot of effort has been put into resolving some of the major challenges of AdHoc net... more In the past a lot of effort has been put into resolving some of the major challenges of AdHoc networks especially the added ones brought up by the mobility of nodes and the absence of infrastructure in MANETs. Unlike MANETs, Wireless Mesh Networks (WMNs) provide flexibility in terms of mobility i.e. Mesh clients can be stationary or mobile and can form a client mesh network among themselves and with mesh routers. WMNs make use of multiple radios and multiple channels per radio for increased capacity, higher throughput and low interference. We gave an overview of the work done on MANETs, experimental Community Wireless Networks (CWNs) and Industrial solutions for mesh networks. We highlighted the differences between WMNS and MANETs and how WMNs can overcome the limitations of MANETs. This paper also compares the feasibility and scope of forecasted applications for MANETs and WMNs. In the end, we gave a conclusion about the commercial viability of MANETs and the growing scope of applications proposed for WMNs.
IEEE Communications Letters, 2010
In order to extend the operating space of single hop High Data Rate (HDR) Wireless Personal Area ... more In order to extend the operating space of single hop High Data Rate (HDR) Wireless Personal Area Networks (WPANs), the meshed configuration can be used for multi-hop functionality. Since the superframe is shared between multiple WPAN piconets for communication, with higher device density, the superframe capacity usually proves to be a bottleneck. Furthermore, when the superframe capacity is shared in a distributed fashion, issues of fairness in time allocation arises. In this paper we propose a centralized scheme for resource allocation specifically in meshed WPANs and induce an element of fairness in time allocation. Simulation results prove the effectiveness of the proposed approach.
Some advantages of meshing Wireless Personal Area Networks (WPAN) are to increase the network cov... more Some advantages of meshing Wireless Personal Area Networks (WPAN) are to increase the network coverage without high transmission power, self- configuration and self-healing, increased route redundancy and fewer retransmissions. This paper discusses the capacity issues when meshing high data rate WPANs i.e. IEEE 802.15.3, IEEE 802.15.3a and IEEE 802.15.3c. The capacity bottlenecks are discussed which arise in multihop communication with a shared superframe. The paper provides detailed analysis on the superframe capacity using different transmitter data rates and highlights the importance of frame aggregation to achieve higher throughput and low overhead. The paper concludes by discussing possible approaches to improve the capacity of meshed WPANs.
IEEE Communications Surveys and Tutorials, 2008
he advent of low-power communication devices started with Bluetooth, which operated via short-ran... more he advent of low-power communication devices started with Bluetooth, which operated via short-range radio frequencies. It covered relatively shorter distances than a traditional wireless local area network (WLAN) with lower throughputs. Due to the popularity of Bluetooth devices and the short operating space, the term personal area network (PAN) came into existence. A wireless PAN (WPAN) is characterized by a small operating space in which information is conveyed among fewer participants with short distances. It is different than a WLAN (apart from the smaller area covered by a PAN) in a sense that it has little or no infrastructure, which allows inexpensive and power-efficient solutions to be implemented for a range of devices. IEEE released the first standard for PANs based on Bluetooth called 802.15.1, which supported data rates up to 1 Mb/s. Although later industrial implementations supported higher data rates (e.g., Bluetooth 1.2, Bluetooth 2.0), they were still not enough to support multimedia applications that were growing in volume and popularity. To overcome this deficiency, IEEE released 802.15.3, which is the standard for high data rate WPANs supporting data rates from at least 20 Mb/s, which is considered to be the lower bound for multimedia applications. The goals for an 802.15.3 WPAN were to pro-vide low complexity, low cost, low power consumption, and high data rate wireless connectivity among devices.
Wireless devices operating under IEEE 802.11 x standards have the ability to transmit at various ... more Wireless devices operating under IEEE 802.11 x standards have the ability to transmit at various data-rates. However, there is no specification in the standard for dynamically selecting a suitable value of data-rate. Numerous solutions are available, mainly from device manufacturers and research community; focusing on a particular algorithm and its suitability for the overall system. However, none of the previous designs were flexible to change their behavior with changes in traffic nature and pattern. Not all traffic types have the same requirements and so should be the behavior of underlying algorithms for data-rate control. This paper highlights various data-rate control algorithms; classifying them on the basis of several parameters and discusses their suitability for different traffic patterns. It also proposes an algorithm, specifically designed for real time services. The cross-layer framework monitors traffic nature and patterns at the transport layer and activates one of three available rate control algorithms which suits the requirements of a particular type of traffic. According to the specific design of a selected algorithm, it then selects data-rate values at runtime. The results verify the tremendous difference among the three algorithms in terms of throughput and delay and signify their usability for specific traffic types.
Computer Communications, 2008
Optimizing the performance of wireless networks for emerging network applications is a highly cha... more Optimizing the performance of wireless networks for emerging network applications is a highly challenging issue. Cross layer solutions offer promising possibilities of joint optimization across the protocol suite. This paper proposes a cross layer framework for rate adaptation in 802.11Â networks. Previous approaches for rate adaptation mainly focused on the factors related to the wireless medium. However, the applications' demands and timing constraints of the underlying protocols were not considered. The solution proposed in this paper tackles these shortcomings with a novel approach by performing rate adaptation according to the changing channel conditions, application preferences and timing constraints of the underlying protocols. The proposed rate adaptation is based on a loss differentiation mechanism which identifies the real cause of channel variations and takes an appropriate action thereafter. The design provides flexibility of tuning various parameters according to application type and offers minimal complexity. The simulation results assert considerable improvements over the previous solutions in terms of the algorithm response to application requirements and dynamic adjustment with variation in underlying protocol performance.
Rate adaptation in multi-rate capable IEEE 802.11x stations is extremely challenging. Previous ap... more Rate adaptation in multi-rate capable IEEE 802.11x stations is extremely challenging. Previous approaches for rate adaptation mainly focused on the factors related to the wireless medium. However, applications' demands and timing constraints of the underlying protocols were not considered. The solution proposed in this paper tackles these shortcomings with a novel approach by performing rate adaptation according to the changing
The future of wireless communications will mainly focus on user centricity and personalization. M... more The future of wireless communications will mainly focus on user centricity and personalization. Multiple networks will be overlaid to provide supplemented connectivity to a user. Competitive options in the current communication technologies need to be carefully ...
Page 1. Rate-adaptation for multi-rate IEEE 802.11 WLANs using mutual feedback between transmitte... more Page 1. Rate-adaptation for multi-rate IEEE 802.11 WLANs using mutual feedback between transmitter and receiver S. Khan1, SA Mahmud1, H. Noureddine2, HS Al-Raweshidy2 1 University of Engineering & Technology, Peshawar ...
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Papers by Sahibzada Ali Mahmud