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Capacity Analysis and Interference Characterization for CDMA Cellular Wireless Communications Systems Based on Statistical Modelling of User Locations

Taheri, Mohammad Mahdi | 2011

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 41708 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Bastani, Mohammad Hassan
  7. Abstract:
  8. 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 of having equal received powers in all cells, we propose a novel method for outage capacity analysis of SIR-based power control DS-CDMA systems. In this method we analyze the outage capacity using the interference to received power ratio, without explicitly characterizing the interference itself. We extend our method for multi service systems and we also calculate the power gain of incorporating SIR-based power control. We then, unlike the previous researchs, relax the assumption of having equal received powers in all cells and extend our method to consider such a case. Based on the previously computed results we calculate the interference statistics and the outage capacity in this new condition.In this thesis we also propose a novel mobility model for the users by which we model both the explicit movement of each user and the set of all users locations are also modeled by a two dimensional point process in each time. We prove that based on this model the marginal spatial distribution of users in a fixed time, is a two dimensional Poisson point process with fixed mean measure over time. Thus, our model is a stationary model. The proposed model provides a general frame work that can incorporate any common single user mobility model and the necessary relations can be derived. We consider a fixed direction and fixed velocity movement on a line for each user. Based on this model we provide analytical relations for interference auto correlation function in uplink of a DS-CDMA cellular system. The interference process in a particular time interval and its auto correlation function are then simulated and estimated based on this mobility model. Comparing the results with the numerical results obtained from the analytical relations shows a good accuracy for the relations to estimate the auto correlation function.

  9. Keywords:
  10. Mobility Model ; Outage Capacity ; Cellular Mobile Telecommunications ; Direct Sequence Code Division Multiple Access (DS-CDMA) ; Two Dimentional Point Process ; Third Generation Cellular Systems ; Signal Interference Ratio (SIR)Based Power Control ; interference Statistics ; Autocorrelation Function

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