We examine two special cases of the problem of optimal Linear Quadratic Gaussian control of a system whose state is being measured by sensors that communicate with the controller over packet-dropping links. We pose the problem as an information transmission problem. Using a separation principle, we decompose the problem into a standard LQR state-feedback controller design, along with an optimal...

We study the problem of scheduling packets from several flows traversing a given node which can mix packets belonging to different flows. Practical wireless network coding solutions depend on knowledge of overhearing events which is obtained either by acknowledgments or statistically. In the latter case, the knowledge about each packet improves progressively with feedback from the transmissions...

The performance of multi-hop wireless networks can be substantially improved by using smart antennas. However, the utilization of smart antennas is quite challenging as the benefit of the different transmission modes strongly depends on specific channel conditions. In this paper we present a novel path selection protocol PSPSA (path selection protocol for smart antennas) and a modified MAC prot...

This paper presents an algorithm to modify the Ad Hoc OnDemand Distance Vector (AODV) routing protocol in order to improve the routing performance in motorway surveillance systems. The proposed protocol has all the characteristics of the original AODV routing protocol since it follows all the steps of the route discovery and route maintenance mechanism of the original AODV routing protocol. The...

In packetized voice communication, speech packets are sometimes lost due to data transmission problems, e.g., signal fading, or interfering users and noise. For the recovery of missing speech packets, different methods are proposed. This thesis analyzes some recovery methods, and four variants of a waveform substitution method used during the objective analysis. This method is based on slow var...

Reliable transport protocols such as TCP (Transmission Control Protocol) are tuned to perform well in traditional networks where packet losses occur mostly because of congestion. However, on the wireless links where packet losses frequently happen, TCP shows a serious drop in performance. In this paper, we propose a scheme, called BSF (Buffer State based Flow control), which can solve this prob...