Mobile Phone Technology

One of the core technologies integrated into 5G is the ability to use mmWaves. these waves are at 26GHz and 40GHz. Due to the physics of electromagnetic waves, whilst these waves have a very large capacity they have short transmission distance. So if these are deployed in a High Street or a shopping mall, there would be a number cells provided to allow the customers access to the network. Each of these small cells needs a backhaul route to the core network. The traditional way to do this in network that run with more usual frequencies (up to 3.8GHz) each cell would be connected by a dedicated fibre cable back to the gateway to the core network.

An alternative to having a single fibre cable for each cell, is to use the 5G network itself as the backhaul. This is the Integrated Access and Backhaul technology. The signals from a small cell are then re-transmitted to another small cell, that is nearer the macro-mast. This can continue until the final mast is reached. Using lots of small cell to small cell backhaul can overload the cells nearest the mast so long multi-hops would be avoided if possible.

In LTE (and earlier) networks, and indeed in 5G networks using lower than mmWave frequencies the use of the mobile network for backhaul was potentially possible but not used as the frequency resource was scarce and needed for access. But in mmWave environments there is much more capacity and backhaul is a possibility. Whilst not used for all mmWave backhaul, it can be used as a mix of technologies to provide a more cost effective solution.