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**1 - 2**of**2**### The 17th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC’06) IMPROVED MODELING OF HIGHLY LOADED UMTS NETWORK WITH NONNEGATIVE CONSTRAINTS

"... In this paper, we deal with the power control problem in a non-uniform and highly loaded UMTS network with omnidi-rectional and smart antennas. If the pole capacity limit in a cell is exceeded no reasonable solution to the power control problem can be obtained with the methods such as the Gaus-sian ..."

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In this paper, we deal with the power control problem in a non-uniform and highly loaded UMTS network with omnidi-rectional and smart antennas. If the pole capacity limit in a cell is exceeded no reasonable solution to the power control problem can be obtained with the methods such as the Gaus-sian elimination, Jacobi, Gauss-Seidel, SOR, or some Krylov subspace projection methods. In such a case, some users are usually removed from the system. In our approach, we solve a non-negatively constrained least square problem with very efficient gradient based linear solvers. This allows us to ap-proximately estimate the powers of all the users even though a pole capacity is slightly affected in some cells. It can be implemented in Radio Resource Management as an effective solution for networks in overload state. Additionally, to reduce a complexity of computation, we extend the dimension reduc-tion technique proposed by Mendo and Hernando to the case of smart antennas. Our considerations are supported with some simulations based on a UMTS network model. I.

### Efficient approximation of . . . IN UMTS RADIO NETWORKS

"... Performance evaluation of UMTS radio networks is involved due to the specifics of W-CDMA technology. A common approach is Monte-Carlo simulation, which is computationally expensive. For purposes such as network planning and optimization, it is vital to obtain estimates efficiently. While an entirely ..."

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Performance evaluation of UMTS radio networks is involved due to the specifics of W-CDMA technology. A common approach is Monte-Carlo simulation, which is computationally expensive. For purposes such as network planning and optimization, it is vital to obtain estimates efficiently. While an entirely analytical and very efficient method using expected coupling systems is known for cell powers, no equivalent for cell’s blocking rates is at hand. This work contributes a highly efficient scheme for estimating blocking rates. We introduce a simple knapsack model for the cell’s capacity, that relies on using fixed estimates for inter-cell interference. The event of blocking and the blocking rate can then be characterized and estimated. We demonstrate on the basis of realistic planning data that the method works efficiently and yields estimates that are sufficiently accurate for applications such as network optimization.