In this paper, a survey of the mobile data traffic growth over the last decade is performed, showing historically how data consumption patterns have evolved. Based on the results from the survey and the most important factors for unprecedented traffic growth from last years, a set of user-centric services and scenarios are identified as the most prevalent by 2020. Based on service characteristics and subscribers' behaviour and consumption regarding traffic generation, four user segments are derived. All these factors allow introducing an impact model that characterises user segment's behaviour over post-4G cellular networks, namely, its consistency and stability towards traffic generation, data consumption and service usage, providing mobile network operators with relevant information to predict user segment dispersion, stability and risk. Real and estimated market data are used to test the impact model, and most relevant results are shown. Overall, the proposed impact model aims to bring together technological, sociological and also economical perspectives into a single analytical framework, meeting both mobile network operators and subscriber's expectations of high quality of service with continuous cost decrease.
In this article the spectrum occupancy of a GSM900 and a DCS1800 band as an analog power or binary quantized power is modeled. In the case of analog power it is presented histograms of the power distribution during one working day. In the case of quantized power it presents the two time statistics, the time period of opportunities distribution and the time between opportunities distribution. The measurement setup is standing in line of sight with the base station. Also, the measurement setup in terms of maximum sensitivity is described and analyzed. Spectrum non occupancy, for a working day, in terms of total time for the GSM900 band and for the DCS1800 band is given.
Abstract-Direct Sequence Code Division Multiple Access (DS-CDMA) signals exhibit cyclostationary properties which imply a redundancy between frequency components separated by multiples of the symbol rate. In this paper a Multiple Access Interference Canceller (Frequency Shift Canceller) that explores this property is presented. This linear frequency domain canceller operates on the spreaded signal in such way that the interference and noise at its output is minimized (Minimum Mean Squared Error Criterium). The Frequency Shift Canceller (FSC) performance was evaluated for a UMTS-TDD scenario and multisensor configurations, where the cases of diversity and beamforming were considered. All these configurations are evaluated concatenated with a parallel interference canceller (PIC-2D). The results are benchmarked against the performance of the conventional RAKE-2D detector, the conventional PIC-2D detector and single user scenario, and we observe considerable performance gains with the FSC specially for the diversity case and a performance close to the single user case when it was evaluated jointly with PIC-2D.
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