US cable companies -- namely Comcast and Charter -- have made a lot of noise in the wireless industry recently. Comcast has launched its Xfinity Mobile service, Charter has announced the start of limited 5G trials and both MSOs have played up the importance of their fixed-line networks as backhaul options for future carrier-driven wireless services.

However, the nation's cable companies are not the foremost experts on wireless technology, and they face some challenges ahead that are difficult even for companies that have been deep in the mobility trenches for years.

To start, there's the issue of WiFi calling. When Comcast Corp. (Nasdaq: CMCSA, CMCSK) announced details of its Xfinity Mobile service, it did so with the note that WiFi voice would not be part of the offering at launch. The company said the feature would be added later on, but didn't specify when. (See Xfinity Mobile Isn't a WiFi Phone Service.)

Charter Communications Inc. hasn't revealed if WiFi calling is in its mobility plans, although VP of Wireless Development Alex Heien declared at the Wi-Fi Now conference in Washington DC this week that it's an "active part of the discussion in our product development." Since Charter won't launch a wireless service until next year, we'll have to wait to see how those deliberations progress.

There may be business reasons not to include WiFi calling early on in cable's mobile efforts. However, even if that's the case, it doesn't mask the fact that WiFi calling is hard to implement, and cable companies may be hesitant in part because of the technical hurdles.

Case in point, Republic Wireless CEO Chris Chuang called WiFi calling his company's "secret sauce" at the Wi-Fi Now event, a feature that the company's team of technologists has been perfecting for years. In particular, Republic Wireless has worked to optimize the WiFi-to-cellular handoff, using its own algorithms to decide when a call should switch from one type of network to another and then managing that handoff without dropping calls mid-stream.

Cable operators, however, have no real-world experience with these handoffs, and there's no guarantee that they can execute them smoothly. In all likelihood, there will be some early headaches as cable companies try to master the technology and encounter the same challenges that many in the mobile industry have spent years working to overcome.

Next, related to the idea of WiFi calling and seamless handoffs is the concept of bandwidth aggregation. Also known as call bonding for voice applications, bandwidth aggregation promises to deliver higher-quality mobile connections by using WiFi and cellular radios simultaneously. While service providers aren't using bandwidth aggregation today, they have every reason to look at it for the future. The issue, as Nicholas Armstrong, head of software development at Carnegie Technologies, explains it, is less about making more capacity available for wireless connections than it is about decreasing latency and increasing cost effectiveness by prioritizing bandwidth from less expensive sources.

In the near term, according to Armstrong, it's application providers who are driving bandwidth aggregation development. However, the advantages for network operators -- being able to offer a better quality of experience and save money in large-scale deployments -- are evident. The technology should grow increasingly interesting as providers operate over more and more spectrum frequency ranges and more and more types of network connections, both licensed and unlicensed.

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Third and finally, cable operators, like their mobile rivals, are now looking at a future where WiFi and traditional cellular connectivity aren't the only technologies dominating the wireless landscape. Cable companies have started to pay lip service to the Internet of Things by slowly introducing broadband gateways that include radios for Zigbee, Z-Wave and other IoT protocols. However, the cable industry as a whole has put the bulk of its resources behind WiFi, and it may need to look at expanding its field of study to include other IoT networking technologies that are gaining traction.

As evidence that there's interest in expansion, Comcast announced just yesterday that it has now joined the LoRa Alliance , an association backing the low-power, wide-area networking standard known as LoRaWAN. Comcast has also started a LoRaWAN network trial in Philadelphia, which it's using for industrial IoT applications.

In the long term, there's a very interesting play for service providers in managing the convergence of many different types of wireless networks, particularly in areas like public venues and smart cities where advanced networks are likely to get deployed first. It's still early days even for the pioneers of some of the new IoT technologies, but eventually there will be numerous different types of wireless connections on offer in the same geographic neighborhoods. When that happens, it will be to cable's advantage to know how to operate across most, if not all, of them.

And if cable companies don't move in that direction, their mobile competitors certainly will.

— Mari Silbey, Senior Editor, Cable/Video, Light Reading