Background

Telecom networks are evolving very quickly, in particular towards converged networks to enable voice, data and video services. The demand is migrating from fixed line telephony services, enabled by circuit switched voice networks, towards triple play services, enabled by xDSL, Wifi, 3G and WiMAX access networks. In order to support these new services, the fixed line transport networks are using packet based technologies to carry information. The network switches are gradually being replaced by routers and softswitches.

Mobile operators are faced today with two antagonist issues, requiring new ways of thinking their backhaul network:

• On the one hand, the overall transport bandwidth and network quality of service requires more powerful and more intelligent equipment to cope with access technologies such as HSDPA, HSUPA, WiMAX and LTE in the near future.
• On the other hand, the backhaul network between access sites and the core network remains a major cost center, representing up to 30% of the network OPEX (the other costs being site lease, operations and maintenance).

Network operators are therefore urged to move into upgrading their backhaul network towards more intelligent and optimised transport solutions to stay efficient in an ever-more competitive market.

The backhaul network usually includes a large number of microwave links. These microwave links are quickly rolled out, cost efficient versus cable layout and the preferred solution in areas where there is little fixed infrastructure (for instance in remote areas or emerging countries). With packet based solutions, the network no longer needs to be a hierarchical network as was the case with traditional TDM technology. Operators can now roll out flat IP networks, such as meshed or routed backhaul networks, getting the associated benefits, particularly in terms of better bandwidth optimisation and enhanced network availability.