Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters

A Channel-Access Framework for Scheduling Transmission Assignments in Ad Hoc Networks with Rate Adaptive Radios

In mobile ad hoc networks transmission-scheduling channel-access protocols are of interest because they can ensure collision free transmissions and provide fair access to the channel. The time taken to gain access to the channel is deterministic and hence these types of protocols can also guarantee a certain quality of service. However, these protocols suffer from two major drawbacks. The first issue is poor utilization of the channel due to fixed slot assignments. Once the slot assignments are decided they are held constant for a period of time. As a result the node to which a slot is assigned may not always have a packet to transmit in its assigned slot. This results in wasted slots and leads to poor utilization of the channel. The second issue is that there is no support for networks with rate adaptive radios. In this work a combined solution to both of these shortcomings is presented. In order to make transmission-scheduling channel-access protocols support networks with rate adaptive radios, a process called slot-packing is developed. The design of slot-packing ensures that it works with any transmission-scheduling channel-access protocol. Using slot-packing, we design and investigate a new protocol called adaptive recovering mini-slot transmission scheduling (RMTS-a) that tackles both the shortcomings and improves the performance of the network significantly. A key feature of our RMTS-a protocol is that if a radio assigned to a transmission opportunity is unable to utilize all of the time slot, other radios in the local neighborhood are given the opportunity to transmit in the remaining time. Additionally, because multiple radios within communication range of a transmitter are likely to be able to decode the payload, packets to multiple neighbors can be packed within a single transmission

Energy-efficient adaptive wireless network design

Energy efficiency is an important issue for mobile computers since they must rely on their batteries. We present an energy-efficient highly adaptive architecture of a network interface and novel data link layer protocol for wireless networks that provides quality of service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations are necessary to achieve energy efficiency and an acceptable quality of service. The paper provides a review of ideas and techniques relevant to the design of an energy efficient adaptive wireless networ

Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks