# 5G Mobile Phone Network Introduction in Colombia
## 3 Frequency Bands in 5G  
One of the bands for 5G network coverage is the Sub-6 GHz, which uses a macro cell base for nationwide deployment with a balance between a high transmission rate and a short-latency for end-users [11; 17]. The Sub-6 GHz band mainly includes spectrum from the long-term evolution (LTE) bands 42, 43 (3.3\(\sim\)3.8 GHz), and 46 (5150-5925 MHz) [18; 19]. The wavelength at 3500 MHz is 86 mm in free space, which is favorable for deploying several antennas on the mobile terminal [20].  
Frequency bands Sub-6 GHz are very crowded and have limited bandwidth available. Therefore, to meet the requirements of 5G in high-performance data transfer, providing an ultra-high-speed mobile broadband several mm-W frequency bands have been proposed and approved in most developed countries. This includes (24 GHz to 29.5 GHz), (37 GHz to 42.5 GHz), (47.2 GHz to 48.2 GHz), and (64 to 71 GHz) [21] with 57 to 66 GHz not requiring a global license [12]. One of the challenges for the use of mm-W in 5G is the design of low-cost, energy-efficient, high-gain broadband antennas capable of overcoming propagation losses [22]. Antennas operating at mm-W are mainly located along the side edge of the mobile device [23].  
_Advantages and Disadvantages in Frequency Band mm-W and Sub-6 GHz in 5G_  
Millimeter waves (mm-W) allow for high bandwidth [12], achieving a low latency and high data rate network [1]. However, its major disadvantage is its limited range without line  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Massive Machine Type** & **Enhanced Mobile** & **Ultra-Reliable, Low-Latency** \\
**Communications (mMTC)** & **Broadband (eMBB)** & **Communications (URLLC)** \\ \hline IoT, asset tracking, smart agriculture, smart cities, energy control, smart homes, and remote monitoring. & Better quality broadband for both indoor and outdoor use, virtual, and augmented reality. & Autonomous vehicles, intelligent electrical networks, remote patient monitoring, and telehealth and industrial automation services. \\ \hline \hline \end{tabular}
\end{table}
Table 2: Typical 5G mobile technology application scenarios.  
Figure 1: International Mobile Telecommunications (IMT) future for the typical application scenarios of 5G communication technology [15; 16].  
of sight (NOS), poor diffraction capability, loss of surface waves, metallic losses [24], and path loss, all due to the high frequency, short wavelength being susceptible to atmospheric absorption, body absorption, and environmental blockage, such as raindrops, snow, and sand [1,6]. It is considered to implement dense networks of small cells with a large number of antennas (MIMO) to counteract the effects of the mm-W channel [25] by improving the coverage capacity through spatial multiplexing. Since small cells have a reduced effective coverage, their deployment can be multiplied in a given area, thus, increasing the number of devices connected to the network as well as raising data speeds per user. Despite this, small cells have difficulty in supporting multiple operators and accommodating various services, e.g., 3G, LTE, 5G, etc. with each mobile operator needing to implement and manage its own individual base station [12]. Table 3 summarizes the advantages and disadvantages of the frequency bands in 5G.