What is a backhaul?

In a hi­er­ar­chi­cal network, a backhaul connects network com­po­nents from the external part of a network to its internal parts. Backhauls are commonly used in cellular networks to connect base stations to the central system.

What does backhaul mean?

A network that is built in a hi­er­ar­chi­cal way is split into separate parts. For example, it can be made up of the core network and an access network. A backhaul connects the access network to the core network or to the central network modules. Backhauls tech­nolo­gies vary according to network and network re­quire­ments. The term itself does not describe one specific type of tech­nol­o­gy but refers generally to different types of in­fra­struc­ture that enable a con­nec­tion between a central unit in a network and other systems or users within the network. Con­nec­tions can be wired or wireless.

When and how are backhauls used?

Backhauls have multiple uses in the IT industry. Here are some examples:

• Radio and tele­vi­sion broad­cast­ing: The backhaul connects reporters on location with the studio broad­cast­ing the program.
• Base stations in cellular networks: The backhaul creates a con­nec­tion to the primary base station con­troller of the cell provider.
• Wireless access points: A wireless backhaul connects various local networks with the internet.

What are different types of backhaul transfer tech­nolo­gies?

Backhaul is a general clas­si­fi­ca­tion and there are many different con­nec­tion and transfer tech­nolo­gies used for back­haul­ing.

Transfer tech­nolo­gies have developed over the years. When cellular tech­nol­o­gy was first in­tro­duced, the con­nec­tion was made on a dedicated line. Depending on the type of line, transfer rates varied between 2 and 34 megabits per second. Due to increased cellular network standards and the need for higher transfer speeds, fiber optic tech­nol­o­gy is often used today to make con­nec­tions.

The following transfer tech­nolo­gies can be used to create a backhaul:

• Copper cables
• Fiber optic cables
• Ethernet tech­nol­o­gy
• Point-to-point radio con­nec­tions
• Satellite con­nec­tions
• Passive optical networks (PON)
• Microwave tech­nol­o­gy
• xDSL tech­nol­o­gy

A backhaul can be im­ple­ment­ed in different types of network topolo­gies. The two methods pre­dom­i­nant­ly used for cellular backhaul im­ple­men­ta­tion are fiber-supported backhauls and wireless point-to-point backhauls. Ad­di­tion­al­ly, ring struc­tures and mesh struc­tures can also function as network topolo­gies. While each of these are solutions in their own right, cellular network providers tend to use a com­bi­na­tion of these tech­nolo­gies.

What are common backhaul chal­lenges?

Due to the de­vel­op­ment of new and more powerful standards in cellular networks, demands on backhauls have increased. More data needs to be trans­ferred at higher rates and with lower latency. As a result, providers need to provide various backhaul con­nec­tions.

Due to this increase in demand, the trend is to build a larger amount of smaller cell towers to increase capacity. This means that backhaul con­nec­tions represent a massive cost when building and main­tain­ing a cellular network. Ad­di­tion­al­ly, an extremely stable con­nec­tion is needed to keep network stability high and service re­quire­ments low.

Rural areas have their own set of chal­lenges when it comes to creating a quick and reliable cellular network. Compared to urban areas, rural areas have less in­fra­struc­ture and larger distances that need to be covered. This is why wireless backhaul con­nec­tions are often used in these areas. Radio com­mu­ni­ca­tions allows for transfer rates of up to 100 megabits per second. The network carries the signal via radio until it reaches a transfer point, which is connected to the network, for example, via fiber optics.