In a multisensor target tracking application running on a shared network, at what bit rates should the sensors send their measurements to the tracking fusion center? Clearly, the sensors cannot use arbitrary rates in a shared network, and a standard network rate control algorithm may not provide rates amenable to effective target tracking. For Kalman filter-based multisensor target tracking, we derive a utility function that captures the tracking quality of service as a function of the sensor bit rates. We incorporate this utility function into a network rate resource allocation framework, deriving a distributed rate control algorithm for a shared network that is suitable for current best effort packet networks, such as the Internet. In simulation studies, the new rate control algorithm engenders significantly better tracking performance than a standard rate control method, while the ordinary data transfer flows continue to effectively operate while using their standard rate control methods.

In a multi-sensor target tracking application running on a shared network, at what bit-rates should the sensors send their measurements to the tracking fusion center? Clearly, the sensors cannot use arbitrary rates in a shared network, and a standard network rate control algorithm may not provide rates amenable to effective target tracking. For Kalman Filter-based multi-sensor target tracking, we derive a utility function that captures the tracking Quality of Service as a function of bit-rate. We incorporate this utility function into a network rate resource allocation framework, deriving a distributed rate control algorithm for a shared network that does not require network re-design. In simulation studies, the new rate-control algorithm engenders much better tracking performance than a standard rate-control method.

We investigate an embedded multicast/broadcast approach for transport of digital video over spread-spectrum code-division multiple access (CDMA) cellular networks. Previous work has shown that the incorporation of a scalable source coding scheme with multiresolution modulation provides a promising design paradigm for the practical realization of the information-theoretic performance predictions originally developed by Cover, which demonstrated that optimal multicast/broadcast performance could be achieved by an embedded transmission scheme. Hence, the major technical challenge associated with the design of an end-to-end embedded multicast/broadcast system is how to match an embedded modulation constellation with a scalable source coding scheme. In this work, taking into consideration both the interference-limited and bandwidth-limited characteristics of a CDMA system, we provide a cross-layer approach incorporating adaptive power allocation and channel coding strategies and effectively match a discrete cosine transform based scalable motion-compensated video encoder to an embedded multiresolution modulation scheme to simultaneously deliver a basic quality-of-service (QoS) to less capable receivers while maximizing both the QoS for more capable receivers and the system capacity. We demonstrate the efficacy of this approach using the ITU-T H.263+ video scalable hybrid coder, although the approach is generally extensible to other scalable coding schemes as well

Depending upon the type of feedback that is utilized, network congestion control schemes can be classified into two categories: marking/loss based (e.g., TCP Reno) or delay based (e.g., TCP Vegas). Delay-based schemes have garnered much attention due to their higher network throughput than loss-based methods. Delay provides a much finer-grained measure of congestion than packet loss or packet marking feedback. However, when there are multiple bottleneck links or inadequate buffer sizes in the path between a source and destination, delay information alone is insufficient for revealing the incipient network congestion. In this paper, we consider the design of a congestion control scheme that transcends the two normal categories and instead jointly exploits both delay and marking/loss feedback. In particular, we introduce the concept of normalized queuing delay, and demonstrate how a controller based on joint feedback provides high throughput even under highly dynamic network conditions as evidenced by ns2 simulations.

We study power control in multicell CDMA wireless networks as a team optimization problem where each mobile attains its individual fixed target SIR level by transmitting with minimum possible power level. We derive conditions under which the power control problem admits a unique feasible solution. Using a Lagrangian relaxation approach similar to F. Kelly et al. (1998) we obtain two decentralized dynamic power control algorithms: primal and dual power update, and establish their global stability utilizing both classical Lyapunov theory and the passivity framework [J.T. Wen and M. Arcak, February 2004]. We show that the robustness results of passivity studies [(X. Fan et al., July 2004), (X. Fan et al., 2004)] as well as most of the stability and robustness analyses of F. Kelly et al. (1998) in the literature are applicable to the power control problem considered. In addition, some of the basic principles of call admission control are investigated from the perspective of the model adopted in this paper. We illustrate the proposed power control schemes through simulations.