Raungrong Suleesathira

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Despite the advantages of direct sequence spread spectrum (DSSS) communications, intentional jamming or interference from other users reduces the robustness of the system to interference. Spreading the message by means of a pseudo-noise sequence, DSSS increases the bandwidth of the transmitted message making it thus di2cult to track the message. Given the(More)
To achieve seamless mobility in integrated wireless and mobile networks, an intelligent vertical handoff mechanism is required to guarantee Always Best Connected. In this paper, a vertical handoff decision algorithm for nonreal time and real time services and network selection for WLAN/WiMAX/UMTS are presented. The conditions of handoff decision procedure(More)
In this paper, we propose a method –based on the discrete evolutionary transform (DET)– to estimate the instantaneous frequency of a signal embedded in noise or noise-like signals. The DET provides a representation for non-stationary signals and a time-frequency kernel that permit us to obtain the time-dependent spectrum of the signal. We will show the(More)
In this paper, a simple method for the DOA estimation in the case of close angles is presented. By means of the spatial MUSIC, the problem of localizing multiple narrowband stationary signals impinging a uniform linear antenna array can be solved. Close direction finding based on such a noise subspace MUSIC estimator can however fail. The presented method(More)
Handoff algorithm is used in wireless cellular systems to decide when and to which base station (BS) to handoff in order that the services can be continued uninterrupted. In this paper, we propose a handoff algorithm based on the neural network in a joint system of terrestrial and high altitude platform station (HAPS) cellular systems. As a revolutionary(More)
Next generation wireless networks must be able to coordinate services between heterogeneous networks using a mobile terminal with multiple access interfaces. One of the challenges for continuous seamless mobility is vertical handoff which is the decision for a mobile node to switch for one network to another different type of networks. Moreover, how to(More)
Next generation wireless networks must be able to coordinate services between heterogeneous networks through multi-mode mobile terminals. Such heterogeneity poses a challenge to seamless handover since each access network has different operations. In this paper, the policies of multiple metrics for handoff to permit connectivity across UMTS and WLAN/WiMAX(More)