# Implementing Smart City Technologies to Inspire Change in Consumer Energy Behaviour
## 5 Communication Solutions for Energy Services in Smart City
### Results of Simulation of Communication Solutions  
Simulation of communication solutions aims at determining the necessary infrastructure (number of antennas) that minimizes the investment costs for wireless sensor networks (SM) of IoT-M2M in an energy dimension of smart cities.  
The functionalities of a network simulation tool are used to carry out a simulation of WAN type wireless communication using two appropriate technologies (3G and WiMAX 802.16x) for cities involved in the ITCity project (Riga, Bucharest, Florianopolis, Santiago, Concepcion and Copiapo). The radioelectric coverage parameters (power spectral density, 24 dbm) used to determine the square kilometres, are equivalent in 3G and LTE (4G). Therefore, for simulation purposes they are similar. In Appendix A, technical parameters of 3G and WiMAX technologies are presented. The utilized network simulation tool determines the number and location of network antennas, number of users for respective technology and the square kilometres of wireless propagation coverage for each city. This tool is called \"Radio Mobile\", program for evaluation of radio propagation, designed by Dr. Ing. [PERSON] [55].  
The Radio Mobile program (ver. 3.8.18) uses digital terrain elevation models to automatically calculate the path profile between the transmitter and the receiver [56] and uses Irregular Terrain Model (ITM) for radio propagation. The Longley-Rice ITM model [57] is a general-purpose model based on electromagnetic theory and statistical analysis of terrain characteristics. This ITM model is valid in a range of 200 MHz to 20 GHz and can be used to predict the attenuation of radio signals in WAN systems. The program outputs calculation for radio link budgets, produces virtual maps and 3D views and provides the information to align the antennas both horizontally and vertically.  
To utilize the program, various parameters must be specified--system, environmental, set and statistical (see Appendix B).  
Table 1 shows results of network simulation carried out for each of the involved ITCity cities. These results consider the number of inhabitants and square kilometres. These factors impact the network deployment, because a certain network antenna can cover a certain area as well as provide a service to a limited number of users in the area.  
The summarized results show a large diversity between the cities of which climate and terrain plays a great role. Regarding climate, with greater amount of rain or snow, the signal power will be impacted, presenting greater problems of attenuation and dispersion. This is the situation of Riga, Romania, Santiago and Concepcion. However, in Florianopolis the climate shows less attenuation, but the most favourable climate is in Copiapo, because the desert climate does not present any type of attenuation of radio signal. Another signal limitation is created by the terrain itself; due to its impact, the network of 3G antennas requires more deployments than WiMAX because of the lower sensitivity of the 3G (\(-60\) dbm).  
As regards the number of users, the WiMAX advantage is greater, since 3G supports a maximum of 150 user per minute, per cell-antenna, while WiMAX supports up to 600 users. Furthermore, having in mind a large quantity of user simultaneous connections, especially for machine communication, smart house communication and automated systems, the advantage of WiMAX can be seen by its 75 Mbps data transfer speed, in comparison 3G only offers 20 Mbps.  
Comparison of the two network technologies has shown the advantage of WiMAX utilization with greater area of coverage with least amount of antenna deployment. This solution does provide the most optimal outcome for most of the cities simulated; however, in Florianopolis the number of antennas for each solution is very similar with minor deviation in minimum coverage. This means that there are situations where 3G network utilization can provide a better result even with its slight disadvantages in comparison to WiMAX.