IP aware radio scheduling: Introducing IP QoS management in LTE networks

Mobile data traffic has exploded over the last few years, especially with the introduction of smart phones in conjunction with increased capacity of mobile networks (HSDPA, LTE). It is commonly admitted that this continuous growth of traffic will induce congestion on the radio segment, usually considered as the bottleneck of the mobile chain. QoS mechanisms adapted to the radio segment are then potentially required when differentiated QoS is targeted. An associated QoS architecture has been defined by the 3GPP (e.g. use of multiple radio bearers per terminal, Guaranteed Bit Rate bearers). It is however inherited from a circuit-based model, which was suitable when voice services were predominant, but which is not so adapted to new packet oriented data services and to open multitask devices. In this paper, after a short summary of the weaknesses of the existing circuit-based QoS model, we introduce the concept of “IP aware radio scheduling”, an IP centric approach which aims at adapting some of the concepts of DiffServ to a wireless interface. The flexibility of this “all IP paradigm” and its relevance to mobile networks are highlighted. Initial simulations results in an LTE environment are then reported, before concluding on the aspects still to be investigated and the next steps.