Usman Sarwar

A gateway solution for IPv6 wireless sensor networks

Wireless sensor networks are expected to be deployed widely in various areas in coming years. The sensor device is small and has low computation power and memory thus perceived as not suitable to be loaded with the high resource IP capabilities. Due to this, the wireless sensor network remains isolated from the Internet. The emergence of IPv6 over low power wireless personal area network (6LoWPAN) has proved that IP communication is borderless and can be used for any devices. It provides a simple alternative to other wireless sensor networks and interoperable with IP-legacy systems and tools. However, the use of short addresses within the 6LoWPAN network is not visible to the outside world and hence a proper gateway is required. In this paper, we provide the architecture of the 6LoWPAN gateway which connects the wireless sensor world to the Internet. Our contribution is to provide direct accessibility to wireless sensor network using short address to full IPv6 address translation at the gateway. Our main focus is the flow of packets to and from the gateway including a simple address translation mechanism. The implementation and the use cases of the gateway are also highlighted.

Performance evaluation of IEEE802.15.4 6LoWPAN gateway

6LoWPAN gateway provides an interface for small size devices to establish IP connection with other Internet devices. One of the standard that 6LoWPAN conforms to is IEEE 802.15.4 which is used for low processing and low power devices. This standard uses frequency spectrum of 2.4 GHz ISM band that overlaps with other standards such as WiFi, Bluetooth and even WiMAX. This causes potential congestion and collision that leads to possible degradation in service quality. The main interference in 6LoWPAN is from WLAN devices. In this paper, we study the deployment of channel allocation by considering the effects of the performance based on interference of deployed environment, size of payload and distance length between sensor node and gateway. These performance tests are executed in the presence and absence of overlapping channel in the environment.

Performance evaluation of 6LoWPAN-based precision agriculture

The use of Wireless Sensor Network (WSN) with IP network in Precission Agriculture (PA) would be an added advantage to existing solutions of PA system. However, existing WSN Technologies, such as Zigbee and other legacy sensor networks are originally design for non IP-based WSN. Hence, they have difficulties in constructing global infrastructure for the precision agriculture. On the other hand, IETF task force has come up with an open standard of wireless sensor network called 6LoWPAN which define connectivity of WSN to IP network using IPv6 protocols. Since the 6LoWPAN is a new technology, the use of this standard for Precision Agriculture is scarce. Most of the works are based on Zigbee. Therefore, this paper is contributing on discussing the performance evaluation and fundamental infrastructure setup for 6LoWPAN based Precision Agriculture.

Session Switching between IP/PSTN Connectivity for Voice Application

Session switching or session transfer across devices has become a common feature in todays telecommunication world, given that a single user could easily own more than one device. However, most of the systems in the literature are designed for homogeneous network, i.e. switching session within a common network such as across only IP devices. In this paper, we design a prototype to support session switching across devices in different network, which is from IP to Public Switch Telephone Network (PSTN) and vice versa. Our prototype is built on top of an IP Multimedia Subsystem (IMS) to leverage on its standard convergence interface with media gateway. Experimental results shown that our session transfer took an extra of 0.31 second more than the IP-to-IP session switching.