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<blockquote data-quote="jeffsw6" data-source="post: 15849" data-attributes="member: 14">Re: iPhone 4 is on Verizon!!!It may interest folks to learn that much of the reason for this has to do with technology choice.CDMA cells can be arbitrarily large, so deploying that technology on towers built for existing AMPS infrastructure, in low-density areas, did not require building new towers or buying more back-haul.&nbsp; RF SNR obviously still limit the range from phones to tower, but it is possible to have huge cells.GSM cells, on the other hand, have a fixed size limit which is much smaller than what is really cost-effective for very rural areas.&nbsp; The limiting factor is not RF SNR but RF travel time from the mobile phone to the tower.&nbsp; To upgrade from AMPS in these areas, more towers had to be built, even though only a small fraction of the available capacity would be used within each very-low-density cell.My understanding is that this problem is solved by somewhat-recent GSM equipment, which can allow a cell to operate in a lower density mode for phones that are too far away.Eventually, AT&amp;T may find it cost-effective to build into very rural areas.&nbsp; Even if they don&#039;t, it will become cheaper for rural wireless carriers to provide GSM service in those areas, increasing the likelihood that you will be able to roam onto another GSM network.&nbsp; Whether or not you want to pay the roaming fees, that&#039;s another question entirely!</blockquote>

[QUOTE="jeffsw6, post: 15849, member: 14"] Re: iPhone 4 is on Verizon!!! It may interest folks to learn that much of the reason for this has to do with technology choice. CDMA cells can be arbitrarily large, so deploying that technology on towers built for existing AMPS infrastructure, in low-density areas, did not require building new towers or buying more back-haul. RF SNR obviously still limit the range from phones to tower, but it is possible to have huge cells. GSM cells, on the other hand, have a fixed size limit which is much smaller than what is really cost-effective for very rural areas. The limiting factor is not RF SNR but RF travel time from the mobile phone to the tower. To upgrade from AMPS in these areas, more towers had to be built, even though only a small fraction of the available capacity would be used within each very-low-density cell. My understanding is that this problem is solved by somewhat-recent GSM equipment, which can allow a cell to operate in a lower density mode for phones that are too far away. Eventually, AT&T may find it cost-effective to build into very rural areas. Even if they don't, it will become cheaper for rural wireless carriers to provide GSM service in those areas, increasing the likelihood that you will be able to roam onto another GSM network. Whether or not you want to pay the roaming fees, that's another question entirely! [/QUOTE]

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