By Julie Bradford
More often than not, the debate around the use of licence-exempt spectrum is driven by passion rather than analysis. After all, this is a debate whose impact goes beyond the technology choice, or financial impact; which technology is selected will set an important precedent for how unlicensed spectrum should be used.
It’s for this reason that we at Real Wireless were delighted that Cisco asked us to simulate and assess options for the co-existence of LAA-LTE and Wi-Fi, helping to redress the balance of the debate by introducing some cold, hard, technical data into the narrative.
At the heart of Wi-Fi’s success is the premise of fair co-existence, enabling multiple Wi-Fi system owners to deploy Wi-Fi access points in the same unlicensed spectrum in an unmanaged fashion. Service providers increasingly wish to also make more use of unlicensed spectrum in order to contribute to mobile system capacity, with one of several means of achieving this being Licensed Assisted Access (LAA-LTE).
Our work for Cisco was presented at the recent CEEC 2015 conference and forms part of their LAA-LTE contributions to 3GPP. Cisco’s contribution turns on a feature called listen before talk (LBT), of which there are a variety of different schemes available.
For this analysis, we used one of Real Wireless’s own, custom-developed tools – in this case, the Wi-Fi and LTE (WaLT) system simulator. Using this tool, we modelled co-existence performance between LAA-LTE and Wi-Fi when set up to use a variety of candidate LBT schemes. These interactions are highly complex, therefore a sophisticated simulator was required, the product of our collective experience and knowledge of modeling techniques.
The results of our simulations clearly demonstrate that the details of the choice of LBT scheme and settings of that scheme matter significantly to achieving fair coexistence.
This was a great project to be involved with, particularly as it gave Real Wireless and Cisco the opportunity to add a much more scientific voice to a hotly contested issue.
Download Fair Co-Existence of Licensed Assisted Access LTE (LAA-LTE) and Wi-Fi in Unlicensed Spectrum