# Coexistence of 5G/6G and Digital Terrestrial Television Networks
## 3 Results of the Analysis
### Interleaved Spectrum  
An alternative approach that could enhance the efficient use of the valuable UHF < 1 GHz radio spectrum, and expand frequency resources for 5G/6G networks, is intelligent sharing [28; 29]. This is feasible where electromagnetic compatibility is maintained, and it aligns with potential secondary spectrum allocations for International Mobile Telecommunications systems as discussed during the ITU's World Radiocommunication Conference 2023. Intelligent sharing demands increased technical flexibility in 5G/6G network planning and integrates seamlessly with emerging cognitive and intelligent radio spectrum access methods, such as cognitive radio, intelligent radio, and dynamic spectrum access. In this model, TV broadcasting frequencies remain untouched. Instead, we define specific geographic zones where TV channels can also serve 5G/6G networks under strict, non-interfering conditions of secondary service frequency allocation. Based on extensive studies by international and national bodies, including ITU Task Group 6/1 and ITU CPM23, it is concluded that bi-directional spectrum sharing between 5G/6G and DVB-T/T2 networks is unviable due to potential severe uplink interference. This interference, coming from high-power high-tower DVB-T/T2  
Figure 4: The coverage of the MUX2 TV network in the modified channel arrangement.  
transmitters, would necessitate extensive separation distances. Nonetheless, downlink-only sharing is possible and promising. In such scenarios, utilizing a supplementary downlink (SDL) in 5G/6G networks appears to be an optimal solution.  
Detailed analysis of deploying 5G/6G networks in the SDL mode within the UHF 470-694 MHz frequency band was conducted, using Poland as a case study. The research aimed to determine the co-channel protection ratio for permissible interference from IMT base stations into digital terrestrial television receivers. Based on typical IMT base station parameters, including effective isotropic radiated power and antenna height, the findings necessitated a minimum 30 km separation distance [23] from the edge of the co-channel DTT allotment area for a base transceiver station operating in SDL mode. Appropriate separation from the allotment areas in the country and neighboring countries had to be taken into account, which is shown in the example plan of the GE06 reservation areas shown in Figure 5. The figure shows that after applying the required separation (marked in yellow), there are significant free areas to be used for the purposes of IMT 5G/6G SDL transmission (white).  
Example results for other channels are shown in Figures 6-8.  
Upon examining all the utilized TV channels, it is evident that across various regions of the country, there is potential to repurpose between 2 and 20 channels--each with an 8 MHz bandwidth--for IMT/5G/6G SDL transmissions, as illustrated in Figure 9.  
Figure 5: An example map illustrating the required minimum protection zones for all reservation areas for channel 21 (case study for Poland and neighboring countries).  
Figure 6: The area of a possible implementation of the 5G/6G IMT network in SDL mode on channel 23.  
Figure 7: The area of a possible implementation of the 5G/6G IMT network in SDL mode on channel 31.  
Figure 8: The area of a possible implementation of the 5G/6G IMT network in SDL mode on channel 48.  
Figure 9: The number of available channels for the IMT/5G SDL transmission mode depending on the 5G/6G IMT base station location which are compatible with the DTT networks.