LTE-WLAN aggregation [Industry Perspectives

Abstract

Cellular operators today have to grapple with the dilemma of unprecedented increase in mobile data traffic coupled with the need to maintain low costs. According to one estimate, global mobile data traffic is expected to multiply more than eight-fold over the next five years to around 30.6 exabytes per month [1]. Increasingly, operators are turning to Wi-Fi offload as a possible solution to reduce the load on their cellular infrastructure, and at the same time provide users with reasonable quality of service (QoS). Apart from increasing network capacity, Wi-Fi offload also holds the promise of providing better coverage, especially when users are near the edge of a cell or in an indoor environment where cellular coverage is weak. The high availability of Wi-Fi networks and relatively low cost of ownership have also contributed to the enthusiastic embrace of Wi-Fi offload by cellular operators. In this column, we begin with a brief discussion of cellular–Wi-Fi integration mechanisms that have been developed in the past, with an emphasis on activities carried out by the Third Generation Partnership Project (3GPP). We then motivate and describe Long Term Evolution-WLAN aggregation (LWA), a Release 13 feature [2] that represents the latest and possibly most ambitious effort to harness the power of Wi-Fi to improve cellular performance. We also discuss the design of a prototype we have built for practical deployment of LWA. The prototype demonstrates that the Release 13 LWA can be implemented with legacy Wi-Fi access points (APs), which minimizes LWA deployment cost. Finally, we provide a brief comparison of LWA with some other competing and complimentary technologies, and describe future advances in LWA.