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We focus on the cooperative mobile positioning based on the received signal strength for heterogeneous environments. We use the least squares method to estimate the channel attenuation coefficients, and hyperbolic method to determine the position. For increasing accuracy, we use different weighting to the adjacent users' data in the attenuation coefficients estimation.
Reza SAADAT Ahmad SHAFIEI AliAkbar TADAION
Mobile positioning using Received Signal Strength (RSS) measurements is regarded as a low cost solution which is applicable in a wide range of wireless networks. In this paper, we propose a cooperative RSS-based positioning algorithm, that relies on the promising idea of mobile to mobile communications in the next generation of cellular networks. Simulations performed in this paper indicate that utilizing the additional RSS data of the short range communications between Mobile Stations (MS's), enhances the accuracy of the traditional RSS-based positioning algorithms.
Rouhollah AGHAJANI Reza SAADAT Mohammad Reza AREF
The focus of this study is the performance of the relaying network with incremental selective decode-and-forward (ISDF) protocol in non-selective slow Nakagami-m fading channels. To enhance bandwidth efficiency, when the direct transmission is not successful the relay is used to retransmit a clean copy of the source signal. The proposed protocol achieves a significant reduction in the power consumption and an improvement in performance compared to the fixed decode-and-forward (DF). The exact symbol error rate (SER) of M-PSK modulation for the ISDF protocol over general fading channels is derived. However, as the exact SER analysis is very complicated, we provide an approximated SER expression. Based on this approximation, we provide an optimum power allocation coefficient where the aggregate transmit power constraint is imposed on the source and the relay. Our results show that at least 50% of total power must be used by the direct link, and the remaining may be used by the relay. Furthermore, power allocation in this protocol is independent of the quality of the source-destination channel and modulation constellation size. Numerical results show that the ISDF protocol can reduce the average transmit power with respect to the fixed DF protocol.