Soft Handover scheme for WSN nodes using media independent handover functions

The present wireless networks are equipped with multiple radio links and operate in a collaborative way to enable continuous data transfer even when any link goes down. The IEEE 802.21 is a standard to provide continuous wireless connectivity between heterogeneous link technologies using media independent handover functions as MIHF. The standard supports handover between IEEE 802.11, IEEE 802.16, 3GPP cellular networks. The wireless sensor networks (WSN) based on IEEE 802.15.4 consists of sensors to monitor various physical or physiological activities and to transfer the collected data to the remote controlling station using a short range radio. But in this case if the wireless node moves out of each other's communication range data transfer is not possible. So in this paper, the WSN communication protocol is made as a part of the IEEE 802.21 stack to explore the handover feature offered by the standard. The proposed stack has an internal partition to make WSN protocol to operate independently with other similar modules as long as they are in range, and the MIH function gets triggered by the application when the home networks are not available thus to provide handover from other link interfaces. The proposed hardware has IEEE 802.11, IEEE 802.16, and 3GPP links which are operated by the MIH functions along with the IEEE 802.15.4 interface. So the WSN modules are provisioned to have connectivity from multiple radio interfaces even if they move out of the coverage range from the current point of access. The proposed primitives for handover between WSN and other links are efficient in providing reliable handoff. Keywords: IEEE 802.21, Media independent handover, IEEE 802.15.4, Wireless sensor network

NEIGHBOURHOOD LOAD ROUTING AND MULTI-CHANNELS IN WIRELESS MESH NETWORKS

As an emerging technology, wireless mesh networks are making significant progress in the area of wireless networks in recent years. Routing in Wireless Mesh Network (WMN) is challenging because of the unpredictable variations of the wireless environment. Traditional mechanisms have been proved that the routing performance would get deteriorated and ideal metrics must be explored. Most wireless routing protocols that are currently available are designed to use a single channel. The available network capacity can be increased by using multiple channels, but this requires the development of new protocols specifically designed for multi-channel operation. In this paper, we propose Neighbourhood load routing metric in single channel mesh networks and also present the technique to utilize multiple channels and multiple interfaces between routers for communication. The traditional routing metrics Hop Count and Weighted Cumulative Expected Transmission Time (WCETT) are used in routing. We compare performance of AODV-HOP, WCETT and NLR routing metrics in singlechannel and multichannel environment by considering throughput and end to end delay performance metrics. Our results show that NLR performs better in singlechannel environment

A Structured Hardware/Software Architecture for Embedded Sensor Nodes

Owing to the limited requirement for sensor processing in early networked sensor nodes, embedded software was generally built around the communication stack. Modern sensor nodes have evolved to contain significant on-board functionality in addition to communications, including sensor processing, energy management, actuation and locationing. The embedded software for this functionality, however, is often implemented in the application layer of the communications stack, resulting in an unstructured, top-heavy and complex stack. In this paper, we propose an embedded system architecture to formally specify multiple interfaces on a sensor node. This architecture differs from existing solutions by providing a sensor node with multiple stacks (each stack implements a separate node function), all linked by a shared application layer. This establishes a structured platform for the formal design, specification and implementation of modern sensor and wireless sensor nodes. We describe a practical prototype of an intelligent sensing, energy-aware, sensor node that has been developed using this architecture, implementing stacks for communications, sensing and energy management. The structure and operation of the intelligent sensing and energy management stacks are described in detail. The proposed architecture promotes structured and modular design, allowing for efficient code reuse and being suitable for future generations of sensor nodes featuring interchangeable components

Genetic Algorithm-based Mapper to Support Multiple Concurrent Users on Wireless Testbeds

Communication and networking research introduces new protocols and standards with an increasing number of researchers relying on real experiments rather than simulations to evaluate the performance of their new protocols. A number of testbeds are currently available for this purpose and a growing number of users are requesting access to those testbeds. This motivates the need for better utilization of the testbeds by allowing concurrent experimentations. In this work, we introduce a novel mapping algorithm that aims to maximize wireless testbed utilization using frequency slicing of the spectrum resources. The mapper employs genetic algorithm to find the best combination of requests that can be served concurrently, after getting all possible mappings of each request via an induced sub-graph isomorphism stage. The proposed mapper is tested on grid testbeds and randomly generated topologies. The solution of our mapper is compared to the optimal one, obtained through a brute-force search, and was able to serve the same number of requests in 82.96% of testing scenarios. Furthermore, we show the effect of the careful design of testbed topology on enhancing the testbed utilization by applying our mapper on a carefully positioned 8-nodes testbed. In addition, our proposed approach for testbed slicing and requests mapping has shown an improved performance in terms of total served requests, about five folds, compared to the simple allocation policy with no slicing.Comment: IEEE Wireless Communications and Networking Conference (WCNC) 201