Muhammad Khalil Afzal

TinyOS-New Trends, Comparative Views, and Supported Sensing Applications: A Review

The wireless sensor network (WSN) is an interesting area for modern day research groups. Tiny sensor nodes are deployed in a diversity of environments but with limited resources. Scarce resources compel researchers to employ an operating system that requires limited memory and minimum power. Tiny operating system (TinyOS) is a widely used operating system for sensor nodes, which provides concurrency and flexibility while adhering to the constraints of scarce resources. Comparatively, TinyOS is considered to be the most robust, innovative, energy-efficient, and widely used operating system in sensor networks. This paper looks at the state-of-the-art TinyOS and the different dimensions of its design paradigm, programming model, execution model, scheduling algorithms, concurrency, memory management, hardware support platforms, and other features. The addition of different features in TinyOS makes it the operating system of choice for WSNs. Sensing nodes with TinyOS seem to show more flexibility in supporting diverse types of sensing applications.

Hybrid Rapid Response Routing Approach for Delay-Sensitive Data in Hospital Body Area Sensor Network

Wireless body area sensor networks (WBASNs) have gained much importance in current research domains and are implemented in real scenarios like hospitals for monitoring patients real-time data. Tiny sensing nodes in WBASNs have limited processing, storing capacity and battery life. The communication of sensing nodes is made energy efficient to conserve the energy of the resource scarce WBASNs. In our paper, we have proposed a routing protocol known as Hybrid Rapid Response Routing (HRRR) protocol for delay-sensitive traffic such as real-time health related data of patients. Time-critical data is forwarded with much less delay due to the minimization of end-to-end delay. Large coverage area of HRRR protocol made its implementation possible in hospital environment to gather the patients data. Therefore, our proposed scheme best fits the requirement for WBASNs in hospitals using sensing nodes for communication. Simulations results show that our proposed protocol has shown much improved results in terms of increased network life time, stability, throughput, and energy efficiency as compared to other existing routing protocols of WBASNs.

QoS-Aware and Heterogeneously Clustered Routing Protocol for Wireless Sensor Networks

Wireless sensor networks (WSNs) have gained much attention in today’s research domain for supporting a wide variety of applications including the multimedia applications. Multimedia applications that are regarded as the quality-of-service (QoS)-aware, delay sensitive, and bandwidth hungry applications require enough energy and communication resources. WSNs being the energy-scarce network have now been designed in such a way that they can support these delay-sensitive and time-critical applications. In this paper, we propose an energy-efficient routing protocol for heterogeneous WSNs to support the delay sensitive, bandwidth hungry, time-critical, and QoS-aware applications. The proposed QoS-aware and heterogeneously clustered routing (QHCR) protocol not only conserves the energy in the network, but also provides the dedicated paths for the real-time and delay sensitive applications. The inclusion of different energy-levels for the heterogeneous WSNs also provides the stability in the networks while minimizing the delay for the delay-sensitive applications. Extensive simulations have been performed to validate the effectiveness of our proposed scheme. Our proposed routing scheme outperforms other state-of-the-art schemes in terms of the delay performances.

Performance Evaluation of DCCP and SCTP for MPEG4 Video over Wireless Networks

In this paper our focus is on the performance of two new transport protocols DCCP and SCTP; the emphasis is to determine which protocol can better meet the Quality of Service (QoS) for MPEG4 video over wireless local area network. Based on results obtained in this analysis it is observed that both SCTP and DCCP achieved better throughput than UDP. For video traffic load of 4 Mbps, throughput achieved by both SCTP and DCCP is almost 100% without expressing any packet loss. With the increase of video traffic load of 5 Mbps and beyond DCCP maintains its throughput and it shows minimum packet loss but SCTP losses its performance. Delay behavior of DCCP also indicates that its performance is better than SCTP. According to our experimental results DCCP better satisfies the quality of service than SCTP for transport of multimedia (video) traffic.

Efficient delay and energy based routing in cognitive radio ad hoc networks

Cognitive radio ad hoc networks (CRAHNs) are multi-hop, dynamic and self-configurable networks, which can communicate without any infrastructure support. Most of the research in CRAHNs has been already carried out on physical and media access control layers, but without effective routing protocols we cannot take full advantage of CRAHNs. In this paper, we discuss the problems in already proposed routing protocols for cognitive radio networks and proposed a novel protocol: Delay and Energy based Spectrum Aware Routing Protocol (DESAR), which consider both delay and energy for the computation of efficient path between source and destination. Simulation results show that DESAR protocol performs better than existing protocol in term of end-to-end delay.

SCTP vs. TCP Delay and Packet Loss

Stream control transmission protocol (SCTP) is a new transport layer protocol, proposed by IETF in RFC 4960. In this paper we have done a simulation-based comparison of important quality of service parameter delay and the impact of packet loss on the throughput using SCTP and TCP Sack as a transport protocol in network simulator (ns-2) in wired network. Our result shows that SCTP and TCP Sack show similar behavior in term of delay in single flow and competing traffic while SCTP achieves higher throughput than TCP when different loss probability is induced in the network.

A survey on routing protocols supported by the Contiki Internet of things operating system

Abstract Standardization and technology advancements have helped the realization of the Internet of things (IoT). The availability of low-cost IoT devices has also played a key role in furthering IoT research, development, and deployment. IoT operating systems (OSs) provide integration of software and hardware components. The availability of standard protocols, heterogeneous hardware support, ease of development, and simulation or emulation support are desirable features of IoT OSs. Contiki OS is one of the contenders for future IoT OSs. It was proposed in 2003, and since then, it has been continually under development and upgraded by professionals, academia, and researchers. Contiki OS supports open source, Internet standards, power awareness, dynamic module loading, and many hardware platforms. The diverse applications of IoT, including smart homes, smart health, smart cities, require efficient network connectivity and demand intelligent routing protocols that can handle heterogeneous, mobile, and diverse networks. Subsequently, designing routing protocols for memory- and central processing unit (CPU)-constrained IoT devices is a very challenging task. Therefore, this paper surveys the state-of-the-art routing protocols of Contiki OS. To the best of the authors’ knowledge, this is the first study to classify the Contiki OS routing protocol literature and list the potential challenges and future work.

Efficient and Reliable MPEG-4 Multicast MAC Protocol for Wireless Networks

Multicasting is the transmission of data to a group of nodes identified by a single destination address. Furthermore, multicasting is considered as an appropriate transmission method for multimedia services. Multimedia applications are expected to become more prevalent over mobile ad hoc networks in the near future. Therefore, achieving reliability in multimedia communications is an important task. Video compression technologies are about reducing and removing redundant video data so that a digital video file can be effectively sent over a network. With modern compression standards, such as Moving Picture Expert Group 2 (MPEG-2), MPEG-4, and H.264, which is also known as advanced video coding MPEG-4 part 10, losses of different frames have different impacts on video quality. In this paper, we propose a leader-based reliable multicast medium-access control layer protocol for multimedia applications to enhance video quality. We present a Markov chain model and numerical formulation of our proposed protocol. Simulation results show that our proposed method is better than other protocols in terms of the number of decodable frames, peak signal-to-noise ratio (PSNR), and video quality.

An Overview of Performance Comparison of Different TCP Variants in IP and MPLS Networks

Researchers have shown considerable interest in TCP variants and their behavior under different traffic conditions by conducting research on congestion management of TCP in IP supporting networks. TCP provides a trustworthy end-to-end data transfer under changeable wired networks. To overcome the problem of unreliability of IP network, TCP is used. Many service providers are now moving to MPLS over Inter- net to transfer data, preferring it over traditional transferring strategies. Different variants of TCP show varying behavior in best effort Internet Protocol networks. This paper presents an extensive investigational study of TCP variants under IP and MPLS networks by focusing Tahoe, Reno, New Reno, Sack and Vegas under File Transfer Protocol (FTP).

A Dual Ring Connectivity Model for VANET Under Heterogeneous Traffic Flow

Vehicular ad-hoc network (VANET) is characterized as a highly dynamic wireless network due to the dynamic connectivity of the network nodes. To achieve better connectivity under such dynamic conditions, an optimal transmission strategy is required to direct the information flow between the nodes. Earlier studies on VANET’s overlook the characteristics of heterogeneity in vehicle types, traffic structure, flow for density estimation, and connectivity observation. In this paper, we have proposed a heterogeneous traffic flow based dual ring connectivity model to enhance both the message disseminations and network connectivity. In our proposed model the availability of different types of vehicles on the road, such as, cars, buses, etc., are introduced in an attempt to propose a new communication structure for moving vehicles in VANETl under cooperative transmission in heterogeneous traffic flow. The model is based on the dual-ring structure that forms the primary and secondary rings of vehicular communication. During message disseminations, Slow speed vehicles (buses) on the secondary ring provide a backup path of communication for high speed vehicles (cars) moving on the primary ring. The Slow speed vehicles act as the intermediate nodes in the aforementioned connectivity model that helps improve the network coverage and end-to-end data delivery. For the evaluation and the implementation of dual-ring model a clustering routing scheme warning energy aware cluster-head is adopted that also caters for the energy optimization. The implemented dual-ring message delivery scheme under the cluster-head based routing technique does show improved network coverage and connectivity dynamics even under the multi-hop communication system.