Downlink TCP performance under cross layer rate and power allocation in infrastructure THPPM UWB networks Ultra wideband (UWB) systems are currently an important wireless infrastructure for efficient shortrange communications and mobile applications. To improve the system efficiency while guaranteeing the radio link level quality of services, the transmission rate and power of the mobile nodes in UWB based infrastructure networks can be dynamically adjusted by executing an optimization algorithm at the access points (APs). In this paper, we present a cross layer rate and power allocation algorithm based on the multilayer model of time hopping (TH) pulse position modulation (PPM) UWB multimedia networks. We consider the performance of the TCP protocol under the proposed cross layer allocation scheme in various realistic UWB based infrastructure networking scenarios.

Fair power and transmission rate control in wireless networks In third generation mobile networks, transmission rates can be assigned to both real time and non real time applications. We address in this paper the question of how to allocate transmission rates in a manner that is both optimal and fair. As optimality criterion we use the Pareto optimality notion, and as fairness criterion we use a general concept of which the maxmin fairness (which is the standardized fairness concept in ATM networks) and the proportional fairness (which characterizes fairness obtained by some transport protocols for the Internet) are special cases.We show that the problem is a joint optimization system of the transmission rate and the power. We formulate the fair allocation problem as an optimization problem and propose both exact as well as approximating solutions. We consider both uplink and downlink problems and study also macrodiversity.