Enhancing WiFi Throughput with PLC Extenders: A Measurement Study

Today, power line communications (PLC) based WiFi extenders are emerging in the market. By simply plugging an extender to a power outlet, a user can create a second access point which connects to a master AP/router using the power line infrastructure. The underlying belief is that this can enhance the throughput that a user can achieve at certain locations (closer to the extender) and potentially increase wireless capacity. In this paper, we conduct an in-depth measurement study to first see if this belief always holds true, and if it does, the extent to which the end-to-end throughput improves. Our measurement study covers both homes and enterprise settings, as well as single and multiuser (or multi-device) settings. Surprisingly, we find that in 46% of cases in an office environment, using a PLC extender does not result in an increase in throughput, even when a single client accesses the network and is located close to the extender. This is because unlike in the case of an Ethernet backhaul, the PLC backhaul could consist of poor quality links (49% of the time in an office environment). We also find that the further away the extender is from the master router, the more likely this possibility becomes. We find that sharing of the PLC backhaul across devices could also be undesirable in some cases, and certain users should connect directly to the master AP in order to improve total throughput. Our study sheds light on when these effects manifest themselves, and discusses challenges that will need to be overcome if PLC extenders can be effectively used to enhance wireless capacity.