Mobile Backhaul

3.5 Summary

Mobile backhaul is an integral part of the mobile network. Logically, the mobile network layer is isolated from the transport network layer. This accounts for a ‘clean’ interface design between the radio network and the transport/backhaul network layers. In practice, interdependencies exist: many functions and characteristics in the backhaul do have an impact on the mobile system performance, and to the end user experience of the service. Also, characteristics of the mobile network influence the backhaul design.

The capabilities of mobile systems have evolved. 2G shifted voice largely to the mobile network. 3G/HSPA, HSPA evolution, and LTE are shifting broadband connectivity as well to the mobile network. With this type of evolution, expansion of the mobile backhaul is often needed. Flat rate mobile broadband tariffs, spectral efficiency improvements, and high data rates of the new radio technologies, have led to an explosion of network traffic in terms of Mbytes per user per month. In 3GPP, this is addressed by defining IP based protocol stacks for the logical interfaces.

3GPP is in general agnostic to layers below the IP layer. For the IP layer, 3GPP includes requirements for both IPv4 and IPv6, and as well in some cases for IPsec. The way the logical interface definitions are written varies in interface standards. As a simplified summary, the backhaul may from a 3GPP viewpoint be implemented with any L2/L1 technology. Also for IPv4/IPv6 it is a network implementation ...