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John and Mat,
If 802 really has an issue with the interference caused by BPL than I think we should do more than set up a liaison, since that does not usually result in any actual work being done. If we have an issue with potential interference than I suggest that 802 send a letter to the BPL group stating our concerns and requesting they do a coexistence assurance document showing that the interference is small. We can offer to work with them. That is where 802.19 could come in since we could help them getting started and review their work.
If Carl is in fact the one with the best background on the potential interference issue maybe he could draft the letter. Sounds like he is passionate about this.
I’m not really an expert but I’ve been trying to follow things. I think you should talk to Carl who is pretty avidly against this technology because of interference issues (primarily in the HAM bands). I tried very hard to bring a PAR like this into IEEE802, but certain folks (I have to give credit to Carl again here) strongly objected.
First, I think this PAR clearly belongs in 802. But when I tried to bring it here, we drove it away. Hence they have now gone elsewhere.
Here is my view on things. This technology definitely is an interference issue. On the other hand, it is already being deployed and I see no way of stopping it. I’d rather have it in 802 where we have the most chance of influencing it and controlling the interference issues. If it goes somewhere else (as it has), I feel we have the least chance of influencing it, and it will be more of an interference issue.
Most versions of this technology operate in lower bands than say 802.11 (<100 MHz). I think it is more likely to be an interference issue for Ethernet than for 802.11. However, there is at least one version of the technology that uses the powerlines as waveguides of a sort and actually does operate on 802.11 frequencies. Well really it works more like a leaky waveguide particularly at corners (I guess EM waves really do have momentum). Even so, operation at 802.11 frequencies is actually my preferred solution since I think it radiates less at these frequencies than it would at the lower frequencies. I think the capacities are higher, and you could even use 802.11, 802.16 or maybe even 802.22 like protocols (once they exist) to run the system. However there is no doubt that the so called ‘junk’ bands would become even junkier with this technology. That said, these bands really were designated in my mind as a protocol free for all, and the protocols fielded are supposed to be designed to handle that environment. As long as the wires aren’t radiating more than any other transmitter is allowed in the band I think it should be permitted. This leaky waveguide effect (assuming it is bidirectional) could even be an advantageous way to set up a ‘wireless’ infrastructure.
Anyway, that’s my take on things. I see nothing in this PAR that restricts them from using 802.11 frequencies, so yes I do believe this is a potential RF interference issue. I further declare that it could be an interference source to wired infrastructures as well depending on the power levels contemplated. While they talk about coexistence, I see nothing about coexistence with other wireless or wired infrastructure (only within the power line community). We should probably insist on requirements being added, or at least have them restrict bands of operation to be <100 MHz. I think that keeps them out of any RF bands we currently contemplate.
Matthew Sherman, Ph.D.
Behalf Of John Hawkins
Not being the technical expert here, I would value the input from other EC members on the issue of potential interference of BPL with other radio technologies.
Of particular interest would be the propensity of such technologies to interfere with 802 technologies. Is there any concern? (will my 802.11 access point still work when my power company fires us BPL?)
Specific to this PAR, should there not be a mention to adherence of FCC Part 15 rules in some way? Should our 802.19 folks liaise with them to ensure coexistence between 802 wireless work and another IEEE standard?