Tianyang Bai - Academia.edu (original) (raw)
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Università degli Studi di Firenze (University of Florence)
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Papers by Tianyang Bai
IEEE Transactions on Signal Processing, 2000
Cellular systems are becoming more heterogeneous with the introduction of low power nodes includi... more Cellular systems are becoming more heterogeneous with the introduction of low power nodes including femtocells, relays, and distributed antennas. Unfortunately, the resulting interference environment is also becoming more complicated, making evaluation of different communication strategies challenging in both analysis and simulation. This paper suggests a simplified interference model for heterogeneous networks. Leveraging recent applications of stochastic geometry to analyze cellular systems, this paper proposes to analyze downlink performance in a fixed-size cell in what is called the hybrid approach. The interference field consists of a contribution from out-of-cell interferers modeled as a superposition of marked Poisson point processes outside a guard region and a cross-tier contribution modeled as a marked Poisson point process. The guard region is used to avoid association issues that would occur if an interferer were located at the cell edge. Bounding the interference power as a function of distance from the cell center, the total interference is characterized through its Laplace transform. An equivalent marked process is proposed for the out-of-cell interference under additional assumptions. To facilitate simplified calculations, the interference distribution is approximated using the Gamma distribution with second order moment matching. The Gamma approximation simplifies calculation of the success probability and ergodic rate, incorporates small-scale and large-scale fading, and works with co-tier and cross-tier interference. Simulations show that the guard region can be tuned to give a reasonable match with performance in a hexagonal grid, and that the Gamma approximation provides a good fit over most of the cell.
IEEE Transactions on Signal Processing, 2000
Cellular systems are becoming more heterogeneous with the introduction of low power nodes includi... more Cellular systems are becoming more heterogeneous with the introduction of low power nodes including femtocells, relays, and distributed antennas. Unfortunately, the resulting interference environment is also becoming more complicated, making evaluation of different communication strategies challenging in both analysis and simulation. This paper suggests a simplified interference model for heterogeneous networks. Leveraging recent applications of stochastic geometry to analyze cellular systems, this paper proposes to analyze downlink performance in a fixed-size cell in what is called the hybrid approach. The interference field consists of a contribution from out-of-cell interferers modeled as a superposition of marked Poisson point processes outside a guard region and a cross-tier contribution modeled as a marked Poisson point process. The guard region is used to avoid association issues that would occur if an interferer were located at the cell edge. Bounding the interference power as a function of distance from the cell center, the total interference is characterized through its Laplace transform. An equivalent marked process is proposed for the out-of-cell interference under additional assumptions. To facilitate simplified calculations, the interference distribution is approximated using the Gamma distribution with second order moment matching. The Gamma approximation simplifies calculation of the success probability and ergodic rate, incorporates small-scale and large-scale fading, and works with co-tier and cross-tier interference. Simulations show that the guard region can be tuned to give a reasonable match with performance in a hexagonal grid, and that the Gamma approximation provides a good fit over most of the cell.