Radio Access Technology and Heterogeneous Networks

- Overview

Cellular networks have evolved over the past two decades. They have transformed to accommodate various technological advancements. They have evolved from 1G to 4G, and global telecom networks are gradually moving towards 5G. 

The network must evolve accordingly to cope with this change. They must move beyond the traditional closed web to the open web. 

- Radio Access Network (RAN) and Radio Access Technology (RAT) 

In a radio access network (RAN), radio sites provide radio access and coordinate resource management across radio sites. Devices are wirelessly connected to the core network, the RAN transmits its signals to various wireless endpoints, and the signals travel with traffic from other networks.

Radio Access Technology or (RAT) is the underlying physical connection method for radio-based communication networks. Many modern cell phones support multiple RATs in one device, such as Bluetooth, Wi-Fi and GSM, UMTS, LTE or 5G NR. More recently, RAT has been used to discuss heterogeneous wireless networks. It is used when the user device is choosing between the types of RATs used to connect to the Internet. This is typically similar to access point selection in an IEEE 802.11 (Wi-Fi) based network.

The new technology will use the Open Radio Access Network (O-RAN). This O-RAN technology provides a more open radio access network architecture than currently offered by telecommunications companies. It will increase interoperability between different vendors and create a more efficient network.

- Traditional Radio Access Networks

A traditional radio access network (T-RAN) is a radio access network (RAN) that has been in use since the advent of cellular technology. It includes the base station (BS) that establishes the connection with the sector antennas. These antennas cover a small area according to their capacity and can only handle the reception and transmission of information within this small area. The physical connection method of the wireless communication network; WiFi, Bluetooth, 4G, LTE, etc. Multi-RAT (Multiple Radio Access Technology) networks and most mobile devices support Multi-RAT. Mobile devices can connect to multiple cellular networks. For example, cell phones can often connect to 2G, 3G, and LTE networks.

Cell phones use radio waves to communicate by converting your voice and data into digital signals to send as radio waves. In order for your phone to connect to the network or the Internet, it first connects through the RAN. RAN uses radio transceivers to connect you to the cloud. Most base stations (aka transceivers) are primarily connected to the mobile core network via fiber optic backhaul.

The RAN provides radio access and assists in coordinating network resources between wireless devices. Devices are primarily connected to cellular networks via LTE or 5G NR connections. Silicon chips in the core network and user equipment such as cell phones or laptops help make the RAN work.

- Heterogeneous Network (HetNet) Environment

Today's wireless infrastructure consists of many elements—macro base stations, metro networks, outdoor and indoor distributed antenna systems (or DAS), small cells, etc.—all working together in a heterogeneous network (or HetNet). Heterogeneous networks are used for wireless networks that use different access technologies. For example, a wireless network that provides service over a wireless LAN and can maintain service when switching to a cellular network is called a wireless heterogeneous network. 3G/4G/5G coexistence and heterogeneous wireless access and fiber-based mobile fronthaul designs are important in order to seamlessly deliver the required data from cloud data centers to wireless users.

The migration of wireless networks to the 5G era is marked by the proliferation of various radio access technologies (RATs). Since existing technology cannot be replaced by another technology, coexistence of today's wireless networks is the best solution to meet users' ever-increasing demands for bandwidth. Therefore, in this heterogeneous environment, users will be able to consume services through different RATs. The choice of RAT is critical and must be carefully designed to avoid wasting resources.

The incremental demand for wireless technology comes from the rapid popularization of mobile devices, which have become one of the necessities of people's lives. Heterogeneous wireless network is a term that refers to a hybrid network composed of different RATs to achieve the concept of always-best connection. In this case, users with multimode terminals can simultaneously connect to different wireless technologies such as 802.16, 802.11, Universal Mobile Communications System, High Speed ​​Packet Access, and LTE.

[More to come ...]