Ultra wideband (UWB) systems are currently an important wireless infrastructure for efficient shortrange communications. To improve the system efficiency while guaranteeing the radio link level quality of services, transmission rate and power of the mobile nodes 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.
As a key pattern in wireless communications, ad hoc is able to improve spectrum
utilization andnetwork throughput evidently. Data existed in ad hoc network get better
security because it willnever be transmitted through the public network. However, there
are significant gaps, in terms ofmovement speeds, areas, etc., among multiple devices
causing network instability problems, whichtraditional routing protocols lack necessary
considerations about. The obvious influence is performancereduction or transmission
failure. Therefore, we propose a perceptual model based on fuzzylogic to obtain degree
of mobility in local region. Establishment procedures include motion
perception,parameters fuzzification, and output normalization. That is, nodes observe
adjacent nodes andcalculates topology change rate and average speed of neighbors. Then
using membership functionfuzzify the relationship between above parameters and mobility
level. Finally, acquiring the normalizedoutput with the help of centroid formula.
Relevant modifications of a reprehensive protocolare implemented to optimize its
robustness in complex situations. Simulation results illustrate thatthe upgraded
protocol can maintain high packet arrival rate and acceptable latency in various
experiments,which proves the usability and efficiency of our model in different mobile
scenarios.
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