DVB-T1/DVB-T2 overlay network optimization with minimal cost by simulated annealing

This paper is focused on coexistence studies of two overlay terrestrial digital video broadcasting (DVB-T) networks: (1) a regular already existing broadcasting network (DVB-T1) and (2) an overlaid network (DVB-T2) for a mobile communication downlink in the same frequency bands, thus reusing frequencies. Thereby, the DVB-T2 overlay network should provide acceptable carrier-to-interference-ratios (CIR) at the mobile terminals and at the same time not significantly impair the performance of the existing DVB-T1 broadcasting network. Thus, both could coexist. We consider our problem as a discrete optimization problem, where number and location of transmitter sites per DVB-T2 cell, power, antenna heights and antenna characteristic are the decision variables. The DVB-T2 network costs and interference constraints are introduced directly into the objective function. We use simulated annealing, the stochastic optimization algorithm to solve our problem. Simulation results show that this approach reduces network costs. Two possibilities to cover DVB-T2 SFN cells using omnidirectional antennas or sector antennas were investigated and compared. Sector antennas appear to provide better results regarding the potential interference from DVBT-2 cells into DVB-T1 cells.