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direct-sequence-code-division-multiple-access--ds-cdma
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DS-CDMA Acquisition Using Adaptive Filters and Sampling at the Rate of Innovation
, M.Sc. Thesis Sharif University of Technology ; Aleam Marvasti, Farrokh (Supervisor)
Abstract
In modern wireless mobile telephony networks, DS-CDMA based physical layers has gained much attention due to their ease of implementation at relatively low overall cost, ability to provide high speed data services, increased user capacity, and many other outstanding features. One of the challenges facing these systems is the synchronization of the users’ signature codes (received via communication channel) to the receiver’s locally generated replica, as the only distinguishing feature between users in such systems is the pseudo-orthogonal properties of these signature codes. To fully utilize this orthogonality, all sequences need to have a common time reference. But when relative sequence...
Power control for multirate DS-CDMA systems with imperfect successive interference cancellation
, Article IEEE Transactions on Vehicular Technology ; Volume 57, Issue 1 , 2008 , Pages 600-603 ; 00189545 (ISSN) ; Khalaj, B. H ; Sharif University of Technology
2008
Abstract
In this paper, the problem of power allocation and optimal decoding order of users for the uplink channel of a multirate direct-sequence code-division multiple-access system with linear successive interference cancellation (IC) is addressed. First, the closed-form expressions of the required received powers at the base station for providing all users with their demanded rates and signal to interference-plus-noise ratios (SINRs) are derived. Then, it is shown that, unlike the case when the IC is perfect, in this case, optimum ordering of users at the receiver, which minimizes the total transmitted power, is a function of both their requested SINRs and path gains. Finally, in searching for the...
Capacity Analysis and Interference Characterization for CDMA Cellular Wireless Communications Systems Based on Statistical Modelling of User Locations
, Ph.D. Dissertation Sharif University of Technology ; Bastani, Mohammad Hassan (Supervisor)
Abstract
In this thesis we consider the effect of random locations of users in the capacity analysis of SIR-based power control systems and comparison to the strength-based systems, for the first time. Unlike previous works we do not consider a simple deterministic uniform model for the analysis. We provide simulations and analytical solutions for calculating the interference statistics, based on which, we not only calculate the interference statistics, but also study the effect of locating a user in every location in the network coverage area and its share in the interference. We also calculate each cell’s share in every statistics of the interference. In this thesis, based on the common assumption...
On the outage probability of sir-based power-controlled DS-CDMA networks with spatial poisson traffic
, Article IEEE Transactions on Vehicular Technology ; Volume 59, Issue 1 , 2010 , Pages 499-506 ; 00189545 (ISSN) ; Navaie, K ; Bastani, M. H ; Sharif University of Technology
2010
Abstract
In this paper, we present a novel and rather simple method for calculating reverse-link outage probability in signal-to-interference ratio (SIR)-based power-controlled direct-sequence code-division multiple access (DS-CDMA) systems. We obtain outage probability for a single-service system using the interference-to-received-signal-power ratio. We extend our method to the multiservice case using the uplink load factor, which is the ratio of the interference to the interference plus noise. Unlike most of the previous works, we employ the 2-D Poisson point process to model the spatial distribution of mobile users in the network coverage area. We approximate the...