Radio Access Network - RAN

Here’s where we all look at the radio network. It is the most expensive part of the network. It will have many parts and pieces and could incorporate even more parts as the network matures. Let’s start by explaining that RAN means “Radio Access Network,” and it will have everything outside between the core and the end user. Most people just think of the radios, but the network is more than just radios and core. It is a complex system of connections that need to talk to each other and the core and the user’s equipment, the UE. The UE could be a smartphone, a laptop, a device in a meter or a video camera, or anything that can connect to the network. Don’t limit yourself to thinking it is just LTE because it could be Wi-Fi or another type of wireless format. 4G is a collection of high-speed formats and 5G will only add more formats and complexity to the network. It’s something that you need to be aware of when moving ahead. Although Wi-Fi never panned out as the carriers had hoped, it is still a major part of the network for offload. 

Remember that this book is about deployments. We’re not diving too deep into the architecture. The heart of the RAN is the BTS, base transceiver station. The radio itself. The eNodeB is much more advanced than the radios of old. It could be any spectrum, but to give you an idea of what is in it I made a drawing below that is typical of today’s BTS. 

Remember that there is more to the BTS than just receive or transmitter. It is also a router that connects the backhaul which could have a microwave. The BTS also has batteries to survive outages. Power backup will be in most macro, and small cells Wi-Fi usually won’t have power backup. Now that we have 5G you will also see servers at more sites to support cloud and edge computing. We need the radio heads at macro sites and antennas. Today’s macro BTS have separated the RF from the controller. It is the evolution that has made things so different. Small cells, on the other hand, are an all in one unit.