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In this paper, we present a system that models the land-mobile satellite communication channel with a Markov chain approach supported by images of the mobile Earth station's (MES) environment. Our method employs a video camera with a fish-eye lens capturing image sequences of the user environment from the position of the moving MES, image and signal(More)
To utilize the spectrum efficiently, nine modulation and coding schemes had been specified in the EGPRS standard. This paper proposes a new closed-loop link adaptation by selecting the transmission mode according to the Rician channel k-factor. The proposed link adaptation incorporates only three identical modulated schemes due to the considerations of(More)
When a mobile station moves, the path loss and shadow fading contribute to the large-scale variation in the received signal strength. The variation of signal strength caused by shadow fadings is a random process, and handover decision mechanisms based on measurements of signal strength induce the "ping-pong effect." This paper proposes an improved handover(More)
A signal attenuation difference of arrival (SADOA) scheme is proposed to combine with the time difference of arrival (TDOA) method for mobile location estimation. On the basis of ratio of distances between the mobile and base stations derived from differences of signal attenuations, each SADOA measurement yields a circle on which the mobile may lie.(More)
Antenna arrays can be employed in mobile communications to increase channel capacity a s w ell as communication quality via spatially selective recep-tion/transmission at base stations. In most wireless communications systems, directions of arrival of mul-tipath signals need to be found for spatial selective transmission. Unfortunately, due to the coherent(More)