Wireless backhaul for LTE - requirements, challenges and options

Next generation broadband wireless technologies such as 3GPP long term evolution (LTE) and WiMax offer significantly higher data rates and require suitably higher capacity backhaul networks. While some service providers have started rolling out WiMax, 3GPP LTE is expected to be standardized during 2009, and many service providers are planning to offer LTE services by 2010-2012. Apart from significantly higher speeds, LTE Base stations (eNBs) require logical full mesh connectivity due to the flat all-IP architecture. This paper explores the wireless backhaul network infrastructure options for addressing the LTE bandwidth and connectivity challenges. The paper details the backhaul requirements for 3GPP LTE as specified in the LTE specifications. The paper analyses different architectures for the backhaul access and aggregation networks. The paper proposes a logical topology model for the aggregation network, examines its realization via carrier Ethernet transport and IP/MPLS, and identifies technology gaps in realizing the logical topology model. The paper concludes that while MPLS satisfies the requirements better today, given the time available for LTE evolution, native carrier Ethernet transport could emerge as a strong candidate for future deployments.