Prashant Pillai

Wireless sensor networks: A survey on the state of the art and the 802.15.4 and ZigBee standards

Wireless sensor networks are an emerging technology for low-cost, unattended monitoring of a wide range of environments. Their importance has been enforced by the recent delivery of the IEEE 802.15.4 standard for the physical and MAC layers and the forthcoming ZigBee standard for the network and application layers. The fast progress of research on energy efficiency, networking, data management and security in wireless sensor networks, and the need to compare with the solutions adopted in the standards motivates the need for a survey on this field.

A survey of architectures and scenarios in satellite‐based wireless sensor networks: system design aspects

This paper is not a survey related to generic wireless sensor networks (WSNs), which have been largely treated in a number of survey papers addressing more focused issues; rather, it specifically addresses architectural aspects related to WSNs in some way connected with a satellite link, a topic that presents challenging interworking aspects. The main objective is to provide an overview of the potential role of a satellite segment in future WSNs. In this perspective, requirements of the most meaningful WSN applications have been drawn and matched to characteristics of various satellite/space systems in order to identify suitable integrated configurations. Copyright

Broadband Satellite Multimedia

The broadband satellite multimedia (BSM) architecture standardised by ETSI defines a satellite independent service access point (SI-SAP) interface layer that separates the satellite independent features of the upper layers from the satellite dependant features of the lower layers, and provides a mechanism to carry IP-based protocols over these satellite dependent lower layers. This enables interoperability at the IP layer between satellite systems of different physical and link layers technologies that fully comply with the SI-SAP concept. This study reviews past and current standardisation activities including the BSM quality of service (QoS) architecture, security architecture, network management that have been carried out by the ETSI Technical Committee-Satellite Earth Stations and Systems (TC-SES)/BSM working group and looking into the future to extend current SI-SAP functions that can enhance existing QoS provision and security management capabilities as well as proposing a mobility management architecture that complies with the IEEE 802.21 media independent handover framework to support BSM mobility and to allow integration of satellite networks with fixed and mobile network infrastructures. A service-based network management architecture is also proposed to allow management flexibility and integration of business and operation support functions, paving the way for satellite integration into the Internet of the future.

Security requirements for IP over satellite DVB networks

The MPEG-2 standard supports a range of transmission methods for a range of services. This document provides a threat analysis and derives the security requirements when using the Transport Stream, TS, to support an Internet network-layer using unidirectional lightweight encapsulation (ULE). The document also provides the motivation for link-level security for a ULE Stream. A ULE Stream may be used to send IPv4 packets, IPv6 packets, and other Protocol Data Units to an arbitrarily large number of receivers supporting unicast and/or multicast transmissions.

Energy-efficient cloud radio access networks by cloud based workload consolidation for 5G

Next-generation cellular systems like fifth generation (5G) are expected to experience tremendous traffic growth. To accommodate such traffic demand, there is a need to increase the network capacity that eventually requires the deployment of more base stations (BSs). Nevertheless, BSs are very expensive and consume a lot of energy. With growing complexity of signal processing, baseband units are now consuming a significant amount of energy. As a result, cloud radio access networks (C-RAN) have been proposed as an energy efficient (EE) architecture that leverages cloud computing technology where baseband processing is performed in the cloud. This paper proposes an energy reduction technique based on baseband workload consolidation using virtualized general purpose processors (GPPs) in the cloud. The rationale for the cloud based workload consolidation model is to switch off idle baseband units (BBUs) to reduce the overall network energy consumption. The power consumption model for C-RAN is also formulated with considering radio side, fronthaul and BS cloud power consumption. Simulation results demonstrate that the proposed scheme achieves an enhanced energy performance compared to the existing distributed long term evolution (LTE) RAN system. The proposed scheme saves up to 80% of energy during low traffic periods and 12% during peak traffic periods compared to baseline LTE system. Moreover, the proposed scheme saves 38% of energy compared to the baseline system on a daily average.

Performance Evaluation of Alternative Network Architectures for Sensor-Satellite Integrated Networks

The last decade has seen an exponential rise in the use of wireless sensor networks (WSNs) in various applications. While these have been primarily used on their own, researchers are now looking into ways of integrating these WSNs with other existing communication technologies. One such network is the satellite network which provides significant advantage in providing communication access to remote locations due to their inherent large coverage areas. Combining WSNs and satellite will enable us to perform efficient remotely monitoring in areas where terrestrial networks may not be present. However in such a scenario, the placement of sensor nodes is crucial in order to ensure efficient routing and energy-efficiency. This paper presents four network architectures for sensor-satellite hybrid networks, sensor-satellite direct communication, connections via a gateway node employing random node layout, grid-based node layout and cluster-based node layout with data aggregation. These architectures were simulated using network simulator 2 (ns-2) and then their packet loss rate, average end-to-end packet delay, and overall energy consumption were compared. The paper concludes by proposing a suitable network topology for environmental monitoring applications.

Evaluating Energy-Efficient Cloud Radio Access Networks for 5G

Next-generation cellular networks such as fifth-generation (5G) will experience tremendous growth in traffic. To accommodate such traffic demand, there is a necessity to increase the network capacity that eventually requires the deployment of more base stations (BSs). Nevertheless, BSs are very expensive and consume a significant amount of energy. Meanwhile, cloud radio access networks (C-RAN) has been proposed as an energy-efficient architecture that leverages cloud computing technology where baseband processing is performed in the cloud, i.e., the computing servers or baseband processing units (BBUs) are located in the cloud. With such an arrangement, more energy saving gains can be achieved by reducing the number of BBUs used. This paper proposes a bin packing scheme with three variants such as First-fit (FT), First-fit decreasing (FFD) and Next-fit (NF) for minimizing energy consumption in 5G C-RAN. The number of BBUs are reduced by matching the right amount of baseband computing load with traffic load. In the proposed scheme, BS traffic items that are mapped into processing requirements, are to be packed into computing servers, called bins, such that the number of bins used are minimized and idle servers can then be switched off to save energy. Simulation results demonstrate that the proposed bin packing scheme achieves an enhanced energy performance compared to the existing distributed BS architecture.

Call Admission Control in Cloud Radio Access Networks

Over the past decade, wireless communications has experienced tremendous growth, and this growth is likely to multiply in the near future. The proliferation of mobile users and an ever increasing demand for multimedia services has resulted in greater capacity requirements. Radio frequency spectrum is scarce and cannot meet this ever increasing demand and the required Quality of Service (QoS) will no longer be achieved if efficient Radio Resource Management (RRM) solutions are not found. Conventional Radio Access Networks (RAN) have standalone Base Stations (BS) with capacity preconfigured for peak loads. These RANs have high call blocking and dropping rates since BSs resources cannot be shared. Cloud based RANs (C-RAN) have been proposed as a cost and energy efficient way of meeting high capacity demand of future wireless access networks by consolidating BSs to the cloud. Instead of relying on rejection of new call requests due to limited BS resources, C-RAN takes benefit of the cloud elasticity, which allows dynamic provisioning of cloud BS resources. This paper presents a novel C-RAN Call Admission Control (C-RAN CAC) to ensure Grade of Service (GoS) by improving blocking probability and improvement of call waiting times. Call blocking probability, call average waiting time and system utilization are used to evaluate the performance of the proposed CAC algorithm.

Fastest-Vehicle Multi-hop Routing in Vehicular Ad hoc Networks

Vehicle to vehicle communication has strong potential to be a mechanism to improve driver’s safety and is now emerging as a prominent research area all over the world. At present, vehicular networks are still not considered to be very efficient because of their rapid topology changes and their highly dynamic structure. However, there has been ongoing and progressive research and development in Vehicular Ad hoc Networks (VANETs) [1] [2] [3] to support vehicle to vehicle communication, particularly in the area of routing in VANETs. In VANETs, routing schemes to reduced overhead and resource consumption is required to ensure successful message transfer within the network. The routing protocol proposed in this paper is based on a multi-hop transfer of a single message by discovering the most suitable vehicle within the transmission range instead of using single hop broadcast (flooding) scheme which results in high packet loss and collision rate. The simulation environment used for proposed algorithm is a tool which combines both network simulator and traffic simulator, known as NCTUns-6.0.

Common RRM in Satellite-Terrestrial Based Aeronautical Communication Networks

This paper presents a collaborative radio resource management (CRRM) scheme to support seamless aeronautical communications using satellite and terrestrial access technologies. The CRRM adopts and extends the IEEE 802.21 Media Independent Handover (MIH) framework and the ETSI Broadband Satellite Multimedia (BSM) SI-SAP concept to split the CRRM functions between the upper layers (layer 3 and above) and the lower layer (link layer and physical layer) of an aircraft terminal. Upper layer functions are managed by an integrated router (IR) on-board the aircraft and lower layer functions are provided by an on-board integrated modular radio (IMR) consisting of heterogeneous radio access technologies. A joint radio resource manager (JRRM) provides the abstraction layer for mapping higher layer functions into lower layer functions to enable collaboration. The CRRM scheme and its associated general signaling procedures are described in detail. Through the CRRM scheme, the connection establishment functions and seamless handovers between different radio technologies are performed by combining MIH primitives and BSM primitives. Analytical time-delay analysis is carried out to evaluate the signaling delay for connection establishment and handover procedures.