FWA is not a new idea with 5G and has been available to anybody tethering since 3G. FWA is comparable to Fibre-to-the-Home as both are connectivity solutions for the edge of the network. 5G mmWave (~25Ghz and above) is promising an alternative to FTTH, with 1Gb per second download speeds. It is therefore worth understanding the technologies and engineering necessary to make FWA a viable or better alternative to fibre.
Verizon has targeted FWA as an alternative to FTTx with its 5G Home service launched across Houston, Indianapolis, Los Angeles and Sacramento in October 2018. Verizon estimates the 5G mmWave FWA addressable market to include 30 million premises. To be successful Verizon’s FWA has to be cheaper than the delivery of FTTx and will have to overcome some quite considerable engineering challenges. These include the roll-out of multiple 5G antennas with small-cell front-haul for extended coverage, the deployment of external to home 5G receivers, a distributed core that can host Mobile Service Edge and CDNs close to the 5G Cell Towers, and a new 3GPP Release 16 Core that can support network slicing for the 28Ghz spectrum.
The above diagram shows a logical architecture for a 3GPP Release 16 compliant new mobile core connected through multiple distributed sites connected to radio site gNodeBs delivering FWA service to the home. A new core is not fully necessary, as Verizon are launching already using their channel coding, multiplexing and interleaving technologies. A new mobile core will be advantageous in guaranteeing the QoS for mmWave FWA slices.
The majority cost for FWA is in the delivery of the radio network and mmWave antenna. Higher costs will always be incurred if RAN planning has not been optimised and necessitates 5G small cell in-fill. For this reason mmWave may be better deployed as new sites in a standalone Model 2x configuration. Other costs include upgrading the mobile core but this cost is shared with other 5G use cases. Spectrum licencing is another important cost. Currently mmWave licence spectrum is relatively available, hence lower cost, and more extremely high frequency is being released by national regulators.
To be competitive FWA must be economically viable against fibre delivered to the home. This includes internet peering & CDNs. In regulated territories like the UK that already have Local Loop Unbundling the competitor CSP can consume service from the distributed site. This has been part of the US regulatory framework since the US Telecommunications Act of 1996 that requires ILECs to lease local loops to competitors (CLECs). In an all fibre model the cost of connection is to the premise (FTTP) or home (FTTH). If regulatory dark fibre or open ducts are in place then the competing CSP can consume those services at a regulatory defined price. In the UK that model is only being developed after initial regulatory challenges and in the US the FCC has not extended enforcement of dark fiber offering since 2014. It is therefore suitable for a US mobile carrier to consider 28Ghz as a more efficient distribution mechanism than FTTH if there are no regulated dark fibre or open-duct solutions available. It is also worth considering that the civils part of the delivery of fibre (the dotted FTTH line in the below diagram) can cost as much as 90% of the total service delivery cost.
A final comparison between FTTH and FWA:
- Same Costs: Network spine, backhaul and equivalent equipment are the same for FTTH & FWA
- Higher FWA Costs: The spectrum licence costs are unique to FWA but due to spectrum availability may not be prohibitive, power & cooling costs are higher for FWA and the maintenance cost of FWA should be higher for exposed antennae
- Higher FTTH Costs: The only cost that is higher with FTTH is the civils part of delivery. This cost can be very high because of the complexity of getting wayleaves and permissions and digging up roads.
- In conclusion, FWA should be more efficient and cheaper service to deliver as long as the network planning is accurate and does not necessitate continual modification based on further cell deployments.