4,355 research outputs found
TCP-Aware Backpressure Routing and Scheduling
In this work, we explore the performance of backpressure routing and
scheduling for TCP flows over wireless networks. TCP and backpressure are not
compatible due to a mismatch between the congestion control mechanism of TCP
and the queue size based routing and scheduling of the backpressure framework.
We propose a TCP-aware backpressure routing and scheduling that takes into
account the behavior of TCP flows. TCP-aware backpressure (i) provides
throughput optimality guarantees in the Lyapunov optimization framework, (ii)
gracefully combines TCP and backpressure without making any changes to the TCP
protocol, (iii) improves the throughput of TCP flows significantly, and (iv)
provides fairness across competing TCP flows
An Extended Network Coding Opportunity Discovery Scheme in Wireless Networks
Network coding is known as a promising approach to improve wireless network
performance. How to discover the coding opportunity in relay nodes is really
important for it. There are more coding chances, there are more times it can
improve network throughput by network coding operation. In this paper, an
extended network coding opportunity discovery scheme (ExCODE) is proposed,
which is realized by appending the current node ID and all its 1-hop neighbors'
IDs to the packet. ExCODE enables the next hop relay node to know which nodes
else have already overheard the packet, so it can discover the potential coding
opportunities as much as possible. ExCODE expands the region of discovering
coding chance to n-hops, and have more opportunities to execute network coding
operation in each relay node. At last, we implement ExCODE over the AODV
protocol, and efficiency of the proposed mechanism is demonstrated with NS2
simulations, compared to the existing coding opportunity discovery scheme.Comment: 15 pages and 7 figure
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
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