Brian's Brain

Those of you who've already read my powerline networking rant published earlier today hopefully came away with my intentionally two-sided conclusion; I remain intrigued with the technology's promise, but the various implementations I've tested over the past five years have consistently underwhelmed me. Since this morning's analysis exclusively focused on functional and performance issues, I didn't mention another key powerline networking issue, that being the continued unwillingness of the three key technology suppliers to bury the hatchet and standardize on a common approach. In summary:

• Today's three primary "200 Mbps" (PHY rate, definitely not effective data transfer rate) competitors are HomePlug AV, championed by Intellon, UPA (the Universal Powerline Association), led by DS2, and HD-PLC (High Definition Power Line Communications), chaired by Panasonic.
• Not only will an added UPA adapter (for example) not communicate with existing HomePlug AV adapters, its presence on the power grid will adversely degrade if not completely squelch the HomePlug AV network. The same undesireable end result will occur in all possible existing-plus-added powerline technology scenarios (i.e. a HomePlug AV adapter added to a UPA network, etc).
• HomePlug AV is a follow-on to the first-generation "14 Mbps" HomePlug 1.0 and subsequent Intellon-only "85 Mbps" HomePlug 1.0 Turbo approaches. HomePlug 1.0 Turbo devices were backwards-compatible with HomePlug 1.0, albeit running at the slower 14 Mbps PHY rate. HomePlug AV is backwards-compatible with neither HomePlug 1.0 nor HomePlug 1.0 Turbo, although HomePlug AV and HomePlug 1.0/1.0 Turbo networks can coexist without degrading each other.

The lingering absence of interoperability leads to consumer confusion; when I have to run a Google search on a networking equipment product name to figure out which powerline vendor's technology is inside it, I daresay the average consumer will do no better (assuming he or she even knows about the interoperability mess). And recently claimed compatibility breakthroughs by all three camps turn out to be mostly mirages under close inspection:

• The IEEE 1901 working group recently wrapped up a draft standard that supposedly merges HomePlug AV and HD-PLC. But read the fine print. Adapters based on IEEE 1901 can support dual MAC/PHY combos in order to implement both HomePlug AV (OFDM) and HD-PLC (Wavelet), but they're not required to do so. Cost-sensitive applications can instead employ a single MAC/PHY (i.e. HomePlug AV- or HD-PLC-only) approach, therefore negating any interoperability potential. Admittedly, IEEE 1901 also adds a mechanism that will allow single MAC/PHY adapters (whenever they come to market) to coexist without degrading each other...although as already stated, they won't necessarily interoperate with each other.
• UPA instead threw in its lot with the ITU's G.hn effort. DS2's Chano Gomez forecasts that the company's first G.hn-supportive chips (which will also be backwards-compatible with UPA) will be out of fab by the end of the year. But G.hn, in spite of all of its advantages, is a clean-slate approach...thereby adding cost to dual-mode (G.hn-plus-UPA) devices, as well as increasing first- (or even third-) time functional risk. When (if ever) will DS2's G.hn-inclusive ICs work as advertised? In this fiscally challenged environment of slashed R&D budgets, will any phoneline or coax networking suppliers also join the ITU parade? And will anyone care if they do, given that today's dominant networking technologies (CAT5 and Wi-Fi) aren't in the G.hn camp?
• There is a potential silver lining to this otherwise grey cloud. Although the IEEE 1901 group didn't publicize this fact, for perhaps obvious reasons, they added a third MAC/PHY option to their draft "standard" ("The wonderful thing about standards is that there are so many of them to choose from") in order to support G.hn. Adds even more cost? Yep. Further increases product development risk? You betcha. But if everyone ends up supporting G.hn, it may be the bridge to interoperability...and maybe even ultimately encourage its adopters to discard their proprietary protocol predecessors. After all, I've long been an advocate of garnering a substantial piece of a very large pie versus the entirety of a much smaller pastry.

At times like these, I wonder if the powerline silicon providers need to take one step back in order to make several steps' forward progress. To use a baseball analogy, they've conceptually built on an X10 powerline control protocol foundation by 'swinging for the fences' in search of LAN and BPL (broadband over powerline) low-probability home runs. However, plenty of opportunities exist for high-probability 'singles' that cumulatively can also rack up lots of revenue and profit 'scores'. Take, for example, this shot:

that I took at the HD-PLC booth at January's Consumer Electronics Show (HomePlug and UPA also had show floor presences, of course, as did their respective chief promoters Intellon and DS2).

It showcases how silicon intelligence at both ends of an electric vehicle charging setup, aided by PLC data connectivity between them, can lead to faster charging times, longer per-charge battery life, a greater number of recharge cycles before batteries need to be replaced, and other advantages. Now, take a look at this video clip from last Tuesday's NBC Nightly News:

The Smart Grid showcased in it has several key attributes:

• Utility companies are able to dynamically monitor customers' power usage, therefore enabling them to more intelligently balance overall supply and demand, as well as to route power where it is needed at any particular point in time, and
• Customers are also able to monitor their homes' and businesses' power profiles, as well as to control lights, thermostats, etc. Ironically, these capabilities are reminiscent of those I'm already able to do with my X10-derivative INSTEON network...whose Universal Devices controller is connected to my router via HomePlug AV!

Applications like these have, I think, appeal to powerline IC suppliers beyond their high volume potential. They're protocol-limited, thereby simplifying the implementation and subsequent support efforts. They're also data bandwidth-limited, not only leading to additional simplification opportunities but also easing operating frequency spectrum requirements, thereby potentially addressing ham radio operators' longstanding EMI concerns.