RADIOENGINEERING, VOL. 26, NO. 1, APRIL 2017 211 DOI: 10.13164/re.2017.0211 APPLICATIONS OF WIRELESS COMMUNICATIONS Interference Analysis between Mobile Radio and Digital Terrestrial Television in the Digital Dividend Spectrum Alberto TEKOVIC 1 , Davor BONEFACIC 2 , Gordan SISUL 2 , Robert NAD 2 1 Access and Transport Network Engineering, VIPnet Ltd., Vrtni put 1, 10 000 Zagreb, Croatia 2 Dept. of Radiocommunications, Faculty of Electrical Engineering and Computing, Unska 3, 10 000 Zagreb, Croatia a.tekovic@vipnet.hr,{davor.bonefacic, gordan.sisul, robert.nadj}@fer.hr Submitted March 31, 2016 / Accepted November 19, 2016 Abstract. This paper is concerned with the analysis of adjacent channel interference of the Long Term Evolution (LTE) mobile system operating in the Digital Dividend into Digital Video Broadcasting – Terrestrial (DVB–T) system. Field measurements in the real LTE network have been conducted in order to define the most significant scenarios and for each of these, Protection Ratios have been quanti- fied. Variable load on the LTE base station has been taken into consideration. Therefore, Protection Ratios for the LTE base station in idle state, and fully dedicated mode have been calculated. Interference mitigation techniques have been reviewed, and an effective deployment method has been proposed. Keywords Adjacent-channel interference, LTE FDD, DVB-T, Digital Dividend, Protection Ratio, Protection Distance, mitigation technique 1. Introduction Due to greater spectrum efficiency, switching to dig- ital terrestrial TV broadcasting frees part of the UHF spec- trum from 790 MHz to 862 MHz called “digital dividend”. The transition process is already completed in many coun- tries. Ever increasing market interest for mobile broadband communications was a main driver for allocating the digital dividend to mobile services in several regions of the world, which occurred at the World Radiocommunication Confer- ence in 2007 (resolution 749) [1]. Although this allocation began in 2015, some EU countries were allowed to utilize this allocation before 2015 [2], with necessary technical coordination with neighboring countries. This decision was very positive from the market point of view, but raised new co-existence issues that need to be carefully analyzed and evaluated:  co-channel interference between neighboring coun- tries or regions, one of them using the digital dividend band for mobile systems and the other for analog or digital terrestrial television [3], [4]  adjacent channel interference within a given territory, where frequencies up to 790 MHz will be used for television and those immediately above this limit will be used for mobile radio communications  co-channel interference within a given territory in the digital dividend band between mobile systems and DVB-C2 [5]. The theoretical analysis of co-channel interference between mobile system and digital terrestrial television has been presented in [6–8]. This is followed by experimental studies based on Monte Carlo simulations, aiming to define co-existence thresholds. Several scenarios between DVB-T and LTE FDD, such as co-channel and adjacent-channel interferences, variation of distance between DVB-T and LTE devices, and different directions of link have been studied in [9]. Co-existence in terms of DVB-T access coverage loss and outage probability has been studied in [10] and [11]. In [12] and [13], simulation analyses are carried out to estimate the adjacent channel interfering effects of LTE Base Station (eNodeB) and User Equipment (UE) on DVB-T receiver systems, through the computation of the correspondent Protection Distance (PD). In both works, the power density spectrum of LTE signals has been approxi- mated using the spectrum Block Emission Masks (BEM) reported on the ETSI recommendations ETSI TS 136 104 V8.7.0 for LTE base stations. In recent work [14], the adjacent channel interference effects of the LTE FDD DL on DVB–T home receivers (only for channel 60) have been simulated, Protection Ratio (PR) as well as the Protection Distance between eNodeB and DVB–T receivers have been calculated. The LTE Downlink Link Level Simulator tool [15] has been used to generate the transmission from a base station to two registered users in a 2×2 MIMO mode. Coexistence between digital terrestrial television and LTE network in the new spectrum allocated from mo- bile communications 700 MHz band has been investigated in [16].