# A Matheuristic for Joint Optimal Power and Scheduling Assignment in DVB-T2 Networks +
###### Abstract  
Because of the introduction and spread of the second generation of the Digital Video Broadcasting--Terrestrial standard (DVB-T2), already active television broadcasters and new broadcasters that have entered in the market will be required to (re)design their networks. This is generating a new interest for effective and efficient DVB optimization software tools. In this work, we propose a strengthened binary linear programming model for representing the optimal DVB design problem, including power and scheduling configuration, and propose a new matheuristic for its solution. The matheuristic combines a genetic algorithm, adopted to efficiently explore the solution space of power emissions of DVB stations, with relaxation-guided variable fixing and exact large neighborhood searches formulated as integer linear programming (ILP) problems solved exactly. Computational tests on realistic instances show that the new matheuristic performs much better than a state-of-the-art optimization solver, identifying solutions associated with much higher user coverage. analogue to digital television around the world has represented a fundamental passage to pursue a more efficient use of the spectrum and the support of a new range of higher quality television services [1; 2]. It is interesting to note that many different DTT standards have been proposed and adopted in different countries. However, among such standards, Digital Video Broadcasting--Terrestrial (DVB-T) [3] is the most adopted around the world, being used in Europe, Asia, Africa and Oceania. The DVB-T standard was published in 1997 and is strongly based on the use of orthogonal frequency-division multiplexing (OFDM). OFDM is a modulation technique that, essentially speaking, subdivides the digital data stream into multiple streams that are transmitted on multiple frequency channels (subcarriers) that are close in the spectrum and are characterized by orthogonality, i.e. they do not interfere with one another despite the absence of guard bands between them (we refer the reader to [4] for an exhaustive introduction to OFDM). Thanks to its attractive features, DVB-T has rapidly spread, but after a few years the need for an updated standard able to follow the evolution of next generation telecommunications services, in particular, by offering improved performance in terms of data rates and spectral efficiency, arose. As a consequence, in 2009 the second generation of DVB-T, namely DVB-T2, was released and published [5], offering improved features, such as more sophisticated modulation and coding schemes that can support up to 50% higher data rates and more flexible bandwidth choices (see e.g., [6]). Passing from the first to the second generation of DVB-T has represented an important technological evolution that, in Europe, has been highly pushed by the European Commission. Indeed, in the European Union, the switch from DVB-T to DVB-T2 is expected to grant a capacity expansion of the digital television system of not lower than 25%, thus allowing a higher number of broadcasters to be active and compete in the market, while also enhancing the pluralism of information [7]. The switch to DVB-T2 will require the television broadcasting companies that are already active in the market to reconfigure their networks, since they will have to embrace the innovative technological features of the new standard. Moreover, there will be the need to configure from scratch the new networks installed by new broadcasting companies entering the market. The technological context of the switch to DVB-T2 is attracting new interest in the development of DVB-T network design tools, especially those including mathematical optimization features, that can improve the outcome of the design. In this work, we thus address the question of developing an innovative optimization algorithm to tackle the complex mathematical models associated with the design of DVB-T2 networks.