Facebook Prep New 60GHz Terragraph Wireless Broadband Tech

After several years of development Facebook’s networking division is finally getting the commercial UK launch of their new Terragraph wireless broadband technology off the ground. This uses a mesh of small cell style 60GHz (mmW) base stations to distribute a gigabit speed broadband ISP connection across communities.

The idea of using the 60GHz millimeter Wave (mmW) band to create a mesh style outdoor Fixed Wireless Access (FWA) network is a fairly recent development (note: the indoor focused 802.11ad WiFi standard has been using 60GHz for years), although we have seen similar technology being deployed by Broadway Partners in rural Wales via the CCS Metnet 60G platform (here) and a few trials with other setups have also taken place.

The use of the 60GHz band enables operators to access a lot of extra spectrum frequency in order to send data, which is excellent for achieving gigabit speeds, except the signals are so weak that they can’t travel very far before losing too much performance (c.250 metres). However by adopting the mesh approach it’s possible to reach further (i.e. each base station acts a bit like an access point and helps to extend the signal for other units).

In other words, a 60GHz mesh FWA network could in theory make more sense in areas where laying optical fibre for FTTP would be prohibitively expensive. In that sense Facebook’s rival Terragraph approach isn’t massively different from the others, except that they have secured significant support from key equipment vendors including Cambium Networks, Common Networks, RadWin, Mikrotik, Siklu, Nokia and Qualcomm.

The strong commercial support for Facebook’s solution, which appears to be a bit simpler than others (based on the WiFi standard), is what could help to make this technology much more accessible to ISPs. Trials have already taken place in a number of rural communities, such as via Deutsche Telekom in Hungary where homes achieved ultrafast broadband speeds of 500Mbps.

The underlying standard being used in this new kit is 802.11ay, which is technically an enhancement to the original indoor focused 802.11ad (WiGig) that first introduced the 60GHz band to WiFi. The new standard quadruples the bandwidth to 8.64GHz and enables MIMO up to 4 streams. In theory this can deliver speeds of 20-40 Gigabits per second or more, but as per the above example that often isn’t so easy to attain in the real-world (Terragraph is aiming for more like 1Gbps to homes).

The new technology also leverages solutions that were originally created to help manage Facebook’s massive data centre infrastructure, such as IPv6-only nodes, an SDN-like cloud compute controller, a new modular routing protocol for fast route convergence and failure detection.

The company also re-architectured the MAC layer to solve the shortcomings of TCP/IP over a wireless link. “By implementing a high performance TDMA-TDD MAC, we saw up to 6x improvement in network efficiency and at the same time made TCP/IP predictable compared to the existing Wi-Fi/WiGig standard,” claims Facebook.

Facebook claims to have tested all of this new kit in both rain and snow without any problems, which has often been a concern due to the inherent weakness of signals in the 60GHz band (i.e. it’s easily disrupted, particularly by physical objects).

At this stage Terragraph is a fairly new entrant and it remains to be seen how much of an impact they’ll have, although the extra competition alone should help to drive down kit costs and that’s good news for broadband ISPs. The fact that the technology has such strong support and is using a familiar standard will also help its chances.

The first commercial kit is expected to enter the United Kingdom and other countries this summer 2020.