FDD could be a good thing. Separate transmit and receive would allow you to deal with white space channels that are not contiguous. With separate TX and RX you could actually make use of the first adjacent channels. The HAAT rules and power/antenna gain limits apply to transmitters. If you have radios separate transmit and receive you could place a receiver anywhere you need it regardless of HAAT and you can build it with any amount of antenna gain you can afford or that the structure will handle. This could possible make up for the low power consumer devices. Those low power levels on VHF channels would go quite far with a high gain antenna at the receiver site. Having access to both high power WISP type channels and the 1st adjacent channels will give a lot more of you access to whitespaces than previously thought.
WISPs just have to remind themselves that they dont have to run half duplex radios on a single channel. TDD may also reduce latency. Another idea I had was to take an additional high power channel and route UDP video traffic in a constant download stream. With some sort of server at your head end to queue up the most popular video content and DVR type devices it could shed some of the load off the regular IP portion of the network. Brian From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of Fred Goldstein Sent: Monday, September 27, 2010 6:41 PM To: WISPA General List Subject: Re: [WISPA] TV Whitespace Questions (channels and equipment) At 9/27/2010 12:24 PM, you wrote: I have not had time to read up on TVWS much yet, but just had a thought over the weekend. Wouldn't it be easy to adapt DOCSIS to TVWS? DOCSIS radios do exist. Transcom and Vecima make them, mainly for the 700 MHz band. Some rural licensed carriers are using them. However, DOCSIS is FDD, so it requires two channels, and the upstream is artificially constrained by some of these systems. I suppose the vendors could adapt them to white space, but I'm not sure if it would be ideal. -- Fred Goldstein k1io fgoldstein "at" ionary.com ionary Consulting http://www.ionary.com/ +1 617 795 2701
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