This qualifies as THE classic example of someone not putting ideas IN CONTEXT. > WiMax has been designed to have a range of 30 miles from a > single, well-located transmitter; within that range, data > transfer rates are anticipated to be 70 Mbps. To put that > in perspective, most radio stations use ISDN connections to > retrieve high-quality audio from remote broadcasts. So let's see. Mobile WiMax would most likely use the OFDM option and frequencies below 11 GHz (starting at 2.3 GHz). With the OFDM option, spectral efficiency is allowed to be set to different settings, depending on robustness needs. As of now, the range is 1 b/s/Hz to 5 b/s/Hz, which is achieved in the usual way (BPSK, QPSK, 16-QAM, 64-QAM, with an assortment of convolutional FEC as well as block RS codes possible for each modulation mode, and optional turbo convolutional coding too). Normal digital radio does the same sort of thing, with the same tradeoff between channel capacity and robustness, and can operate even at frequencies in the MF, HF or VHF bands. And the spectral efficiency is typically in the 1+ b/s/Hz range. Because digital radio is aimed at streaming media and mobility, it doesn't need to provide the wide range of setup options WiMax provides (such as ATM framing, for example, or 5 b/s/Hz spectral efficiency). If you load radio stations into WiMax frequencies, you take away capacity for two-way broadband subscribers using WiMax and you waste the radio spectrum. If you modify the WiMax standard to use radio frequencies, you are simply playing musical chairs with spectrum. > A single WiMax connection has the equivalent capacity of > more than 500 ISDN lines. As a further comparison, many > radio stations have T-1 connections to the Internet for > their computer networks. A single WiMax connection would > offer the equivalent of 60 T-1 lines, or seven DVD-quality > video signals to each individual wireless user. Proving what? If a radio station needs 128 Kb/s, it requires no less spectrum on the WiMax frequencies than it would on the radio frequencies, for equal robustness. Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.