said by MyDogHsFleas:How good is this spectrum? Characteristics? Will it work with existing phones?
The characteristics should be comparable to other LTE bands since it is between band 1 and band 7 in frequency. However some of it will depend on the signal strength that will be used (I'm not sure whether the agreement with Sirius included a cap on signal strength).
There is already an LTE band specified in that frequency range (band 40) used (or intended for future use) in parts of Asia using TD-LTE.
The probability of any existing handset working with this new WCS LTE band is next to nil. For softradio handsets it may only take a software update to make them compatible but I don't see any incentive to either AT&T or handset manufacturers to produce such an update when they can make more money selling you a new phone.
It is not even clear that AT&T is planning to use that band for mobile phone applications. They may just use it for fixed wireless data networks where it is much easier to control interference issues then with mobile applications.