3.1.1 Radio Technologies and Backhaul
Since the introduction of HSDPA in 3GPP rel-5, and into the networks since the mid 2000s, mobile backhaul became a topic of increased importance. Introduction of LTE is a continuation on the same theme. Enhancement of the air interface and mobile network capacities have proven not to be always easily met on the backhaul side. Expanding the transport network capacity can be both time-consuming and costly.
Existing TDM networks may (and will) continue to be used, but they lack the capacity and flexibility of packet networks. An expansion into mobile broadband requires packet technologies, which is a topic for Chapter 04 of this book.
While the present networks continue to serve voice as well as data users, new radio technologies are introduced. Multiple radio networks are operated in parallel. The systems may use their own separate backhaul, but for cost efficiency, a single packet network is a consideration. This requires that the common packet network can meet the needs of all of the systems.
3GPP radio networks, 2G, 3G, and LTE, have their own needs for the mobile backhaul for delay, loss, QoS, synchronization, security, resilience and so on. Requirements originate from the functional split between elements, and from the type of protocols operating at the radio network layer; and from the end user service.
Even though many aspects in the system architecture of the mobile networks are different, there are also commonalities. The development ...