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Alexander Chemeris alexander.chemeris at gmail.comJean-Samuel, thank you for the detailed answer. I agree that 2 weeks of delay is ok, but 2 months is definitely not. We should optimize our processes as much as we can. Regarding the need for the preselector, I have no other option as to trust you and Andrey that we need it even for the mid-range BTS. Could we start updating UmTRX and manufacturing the next prototype batch while still discussing the mezzanine board? This would allow us to get to the result faster. 2012/3/18 Jean-Samuel Najnudel - BJT PARTNERS SARL <jsn at bjtpartners.com>: > Hi Alexander, > > I fully agree with your vision. Especially that "the best is an enemy to a > good". Moreover, it is also very important for me to deploy the UmTRX in > Mayotte ASAP as my local partners would pressure me quite a lot in the near > future. > > However, I really belive this preselector is not just for scoring the best > performances as possible as an RF geek, cool and fun challenge. We really > need a preselector, not only to pass the GSM specs. I do not care that much > about the GSM specs, especially the hard to pass macro BTS specs. However, > as I mentioned you in Berlin in last december, I really think sampling the > whole 1.5 MHz band would be a real problem. The preselector is good to pass > the spec but it is also the only reasonable solution to lower the sampling > band down to about 200 KHz. Actually, I would really need this. Even for my > experiment network in Mayotte, this would not be realistic to deploy the > network and provide reliable services without this preselector. > > I really think this preselector is mandatory, in practice, even if we do not > care about the GSM specs. Without this, I would not even be able to deploy > the UmTRX in Mayotte. > > I agree with you when you mention some markets would still not need this > preselector. > First market is lab equipments. However, I am not sure volumes would be that > high, especially as even a basic low cost SSRP is good enough for many lab > use cases. > Second market is the femtocell market. However, for this market, the UmTRX > would anyway be too expensive for most business cases. Except ip.access who > can sell much more than everybody else because of their first mover > advantage, most of the femtocell vendors target list prices around 300 Euros > (eg: HSL) and even lower (most 3G femto vendors). Considering this > competition, I believe it would be really difficult to succeed in the > femtocell market with the current UmTRX design. We would need something even > more low cost orienteed and probably also more embedded. > > The market I relly believe in is the mid-range mid-capacity BTS market. > There are many high performance macro BTS vendors. There are many simple, > cheap and reliable femtocell vendors. There are not much mid-range BTS > vendors. If we want something than can cover a few kilometers range, that is > energy efficient and which use IP standards, you only have something like 3 > vendors: Vanu, VNL and IP.access. These guys are really expensive. Offering > a better value product would not be that difficult, at least compared to the > other markets. > > Moreover, this mid-range mid-capacity BTS market is potentially huge. This > is the most suitable system we would need to cover most of the next 2.5 > billion guys who do not have a reliable and affordable phone service > (sometimes just no service at all). > > Again, I agree with you, Time To Market is very important. However, I do not > think a few weeks delay would make you miss the opportunity. > > Also, the customers on this market (mainly rural and local carriers) would > have very similar needs as mine. Most of them would probably need to get a > narrow sampling band (< 1.5 MHz) to avoid problems with interferences (1st > TRX to the other, other existing carrier...) causing, among other issues, > ADC saturation. As me, these customers would need the preselector. > > The preselector would anyway need a VCO/PLL, a mixer and an IF SAW filter, > even if we do not expect to pass the GSM spec. Why not trying to select good > performance components to try (not guarantee but just try) to pass this > spec. This would not need much more research and development efforts and > total BOM will not be that much more expensive. Moreover, we can really > expect some of your customers would not agree to deploy a system that does > not pass the GSM spec. A mid-range BTS would need a Tx power around 5 to 10 > Watts. Above 2 Watts, the hardware is considered as a macro BTS. Considering > this, I really think we should try (not take one year delay for this but > just try) to pass the GSM macro BTS spec. > > Honestly, I may be wrong but I do not believe Andrey will take that much > time to design the preselector. For the BOM extra cost, we talk about 60 USD > per UmTRX board. I agree with you, this is not nothing but this really worth > the money. I actually believe value would be really good with this. Even > with my very tight budget, this would not be able problem for me to pay > this. The extra cost would be much lower than all the worries and time spent > on frequency planning, interferences and blockers problem solving on the > field. > > Anyway, I also really think, even with the high performance preselector, the > UmTRX system is still really cost effective compared to the competitors. I > really feel confident about this. > > Best regards. > > Jean-Samuel. > :-) > > > > On Sun, Mar 18, 2012 at 8:45 AM, Alexander Chemeris > <alexander.chemeris at gmail.com> wrote: >> >> Andrey and all, >> >> 18.03.2012 2:31 пользователь "Andrey Sviyazov" <andreysviyaz at gmail.com> >> написал: >> >> Regarding the GSM spec, I believe these blocker tests are hard to pass >> >> and not that useful in most practical situations. However, I do not care >> >> that much about passing this spec for my network deployment in Mayotte but I >> >> really believe passing the spec will be very important for you if you wish >> >> to sell your hardware solution to some major operators. Moreover, as we >> >> would anyway need a superheterodyne selective filtering to get a reasonably >> >> narrow Rx sampling band (< 1.5 MHz LMS band), it does not cost that much >> >> more to try to pass the GSM spec. >> > >> > You right, it is important for us and may be it is really important for >> > systems with high channel dencity. >> >> I completely support everything which could make our product better >> without increasing its cost. But we also must ensure to release UmTRX in >> time. What we all should keep on mind is that "the best is an enemy to a >> good". We should focus on those 10% of simple tweaks which bring us 90% of >> improvement. Otherwise we'll be swamped with the other 90% of tweaks and >> will miss the market opportunity. I can't stress it more - we MUST release >> UmTRX ASAP. Even if it doesn't meet macro-BTS requirements. We'll be able to >> fix this in the next version if ever needed - we can't know the real demand >> until we release the first version. >> >> I would be glad of what I've just said is obvious and already lives in >> your heart. Otherwise it's extremely important you understand this deeply, >> not formally. Please let me know if you don't, I'll explain in more details. >> >> > Furthermore, it is very easy to lose the reputation of the product, but >> > it is very difficult then to fix it back. >> >> This is true. And the best way to keep the reputation is to realistically >> understand UmTRX capabilities and avoid overmarketing. In other words, with >> just reasonable product quality, our reputation depends solely on the right >> marketing. E.g. we might explicitly warn customers that it's not suitable >> for macro-BTS installations and they could do so on their own risk only. >> >> > I think, low cost doesn't sign low quality, so we must to have good >> > hardware on market for good sales and promote OpenHW :) >> >> This is very true. Just keep in mind that "good hardware" means "minimally >> viable hardware at low price" and doesn't mean "super high quality mumbo >> jumbo with many zeros in the price". Our customers value simplicity and low >> cost over complexity and golden plates. >> >> That said, I can't help with decisions on the RF side and here I rely on >> you, guys. That's why it is so important for you to understand all these >> "abstract" marketing ideas. >> >> Sent from my Android device. >> >> -- >> Regards, >> Alexander Chemeris >> CEO, Fairwaves LLC >> http://fairwaves.ru > > -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru