Chapter 21: Cellular Network Theory

Learning Objectives

• Derive the signal-to-interference ratio (SIR) in a hexagonal cellular layout with frequency reuse factor $N$ and show that co-channel distance scales as $D = R\sqrt{3N}$
• Apply stochastic geometry and the Poisson point process (PPP) to model base station locations and derive the coverage probability in closed form as a function of the path-loss exponent and SINR threshold
• Analyse heterogeneous networks (HetNets) with macro and small cells, including the role of range expansion bias in cell association and load balancing
• Define and compute the area spectral efficiency (ASE) as a function of cell density and show how it trades off against per-link SINR in interference-limited regimes
• Model handover mechanisms including the A3 event, hysteresis margin, and time-to-trigger, and quantify the ping-pong rate as a function of UE velocity
• Quantify the SIR gain from sectorisation and explain how directional antennas reduce co-channel interference in practical deployments
• Contrast the deterministic hexagonal model with stochastic geometry approaches, understanding the strengths and limitations of each for system design