Just received a new PRL on my Evo LTE

[sixtyin3]

Would this have anything to do with identifying LTE signals now? New PRL is 25005, just got pushed on its own this afternoon.

[S4GRU]

Would this have anything to do with identifying LTE signals now? New PRL is 25005, just got pushed on its own this afternoon.

 

No. PRL's will only control 1x and EVDO. LTE is not handled by PRL's. LTE is controlled by the SIM card. In Sprint LTE devices, the SIM card is sealed and not accessible.

 

Robert

[sixtyin3]

Good info as always, thanks Robert.

[Xlegendxero]

a bit off topic, are PRL's dependant on device and/or market?

[xenadu]

Does this mean the next iPhone will be the only Sprint LTE phone with a SIM card? Hmm.....

 

I still wonder if the commitment to a large purchase wasn't Sprint buying support for 800 SMR in a future product. I know Qualcomm said they are working on a new radio chip that will support some ridiculous number of bands in one package. Don't know when or if that includes SMR but it would be interesting.

 

Oh and software radio has just shrunk down again... It now occupies a single small PCI Express slot and cost about 700 bux. That's down from three external boxes and 1500 two years ago, which was down from 20 grand and half a room 15 years ago. At this scaling rate, I would expect cell phones to be using software radio within 10 years which combined with advanced antenna technology should completely eliminate the band support issue. I know the chip makers are looking at it due to the R&D and difficulties trying to support all the fragmented cellular bands (which will only get worse over time).

[Turas]

 

Oh and software radio has just shrunk down again... It now occupies a single small PCI Express slot and cost about 700 bux. That's down from three external boxes and 1500 two years ago, which was down from 20 grand and half a room 15 years ago. At this scaling rate, I would expect cell phones to be using software radio within 10 years which combined with advanced antenna technology should completely eliminate the band support issue. I know the chip makers are looking at it due to the R&D and difficulties trying to support all the fragmented cellular bands (which will only get worse over time).

 

This would be nice.

[CriticalityEvent]

Does this mean the next iPhone will be the only Sprint LTE phone with a SIM card? Hmm.....

 

I still wonder if the commitment to a large purchase wasn't Sprint buying support for 800 SMR in a future product. I know Qualcomm said they are working on a new radio chip that will support some ridiculous number of bands in one package. Don't know when or if that includes SMR but it would be interesting.

 

Oh and software radio has just shrunk down again... It now occupies a single small PCI Express slot and cost about 700 bux. That's down from three external boxes and 1500 two years ago, which was down from 20 grand and half a room 15 years ago. At this scaling rate, I would expect cell phones to be using software radio within 10 years which combined with advanced antenna technology should completely eliminate the band support issue. I know the chip makers are looking at it due to the R&D and difficulties trying to support all the fragmented cellular bands (which will only get worse over time).

 

I can't find the Engadget article, but is this what you were talking about?

 

http://www.lightreading.com/document.asp?doc_id=222377

[xenadu]

Well I'm not sure, they break their product line into different pieces. I don't know if that SoC has the wireless chip built in or not... Eg the MDM9615 is just a modem so it pairs with another chip as the processor and then there are power amps and such to worry about. So even if the MDM9615 supports 27 different frequency bands that doesn't mean a specific device can make use of it because it might lack the power amps/filters to do so.

 

Edit: it's the WTR1605 that does the actual transceiver work so it has to understand TDD vs FDD, etc. The MDM is the modem so it has to speak the actual protocols (CDMA, GSM, etc). So the device hands a stream of digital data to the modem which converts it to the actual protocol you are speaking and the WTR1605 encodes it as an analog waveform suitable for broadcast, then the appropriate power amplifier and filters boost the power without spilling across into neighboring frequencies, then the proper antenna actually resonates, thus broadcasting the radio waves.

 

So even if the modem speaks LTE and the WTR speaks LTE FDD, if there is no power amp hooked up to the SMR output it goes nowhere. If there is no antenna of the appropriate length hooked to the power amp then the signal goes nowhere (or on the wrong antenna the power is wasted instead of broadcast).

 

IANARE (I Am Not A Radio Engineer), but the actual 800mhz antenna should work fine for SMR, I just don't know if the WTR supports it. If so, I suspect the power amp would work fine, it is the filters that are the problem... You would need separate filters for the old A/B 800Mhz licenses versus SMR. I have no cue how configurable those filter banks are (if at all).

 

Why the filters? No signal generator or power amp is 100% perfect so you will get harmonics and distortion. If you don't filter properly, the power amp will waste a lot of its power amplifying the useless harmonics, which also pollutes other radio bands. I suspect that the filtering is actually far more important on the receiving side... You need to filter out the unwanted frequencies before you amplify the raw signal, but that has to be dynamic as you switch frequency bands.

 

Part of what software radio does on the receiving side is just amplify everything and let the computer use FFTs and other algorithms to pull the wanted signal out of the noise digitally. Right now that takes too much processing power (thus space and battery) to do, so you use purpose-built chips to do the work... The trade-off is they can't work with frequencies and protocols they aren't originally built for.

 

 

More knowledgable folks feel free to correct me!

 

Edit2: WTR1605L has seven ports, three sub-1GHz, three upper, and one super-high 2.5Ghz. I'm not sure what the current iPhone does but if they want to keep it a single world phone then one of the lower ports will be Cellular 800 and one will be the B/C 700 which is what AT&T is using. One of the upper will be PCS and one will be AWS. What remains to be seen in my mind is will the 2.5Ghz be the Clearwire band? I suspect the last upper port will go to some non-US band. That leaves one lower port... Does it go to the 700Mhz A frequencies? Or does it go to 800 SMR for Sprint?

 

We know that Verizon is trying to sell its A/B 700Mhz bands. We also know that mostly small rural folks own the other A blocks. We also know they were demanding the FCC force device makers to support A/B/C in their chipsets to enable roaming.

 

This is nothing but speculation.... But it is *possible* that the Apple/Sprint deal agreed to 800 SMR to fill that last lower port and Apple told the rurals to go pound sand. I suspect Verizon either balked at the deal Apple offered or was already on the fence about ditching their 700 A/B. Again, pure speculation on my part. It is also possible that Apple may not be able to keep a single model world-wide but that won't help Sprint at home because they still have the upper-lower 700 vs SMR+upper 700 choice to make. But I can totally see why the SMR support would be worth any price to Sprint... Who can refuse to support it at no charge if Apple is doing it? No one will balk, certainly not the likes of Samsung, HTC, or Google. It also gives Sprint a cheap way to massively improve their rural coverage. So in the long term even if Sprint has to give away some iPhones to fulfill their contract with Apple, it may be worth it to turn what was a worthless Nextel millstone into an extremely valuable asset.

 

I don't believe any other regions have any active deployment at 2.5Ghz like Clearwire does so that makes support for their network seem like a done-deal. It would also explain Sprint's sudden renewed interest in Clearwire as it means the next iPhone and iPad can offload to Clear in dense urban areas.