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(#1)
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Senior Member
Prepaid Expert
Posts: 197
Join Date: 26 Dec 2004
Location: Sheffield UK
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![]() I have a Star W007 (for sale - see for sale on here).
It's to stop any signal conflicts - one SIM is on 3G, the other on 2G - means they can both have best signal reception/transmission conditions. If two 3G handsets are in close proximinity, the spread spectrum nature of the signals means you get a lot more bad packets. It's a clever solution to the problem of using two 3G transceivers in close proximity. The Star W007 is software-switchable in this regard - i.e. you can switch which transceiver module pairs with which SIM card. +Steve ![]() PO Box 1014, Sheffield S10 5YG, UK Home mobie: Telefonica O2 Other UK mobiles: 3, Vodafone, Virgin Foreign SIMs: Toggle (multi); Germany (Fonic); Poland (Orange PL); Skype: stevewgold |
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(#2)
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Senior Member
Prepaid Professionist
Posts: 1,399
Join Date: 15 Nov 2006
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Also keep in mind that the 5 MHz channels of UMTS include guardbands of 580kHz at the upper and lower end. So the actual carrier bandwidth of a UMTS channel is only 3840kHz and all carriers are separated by 1160kHz which should suffice to avoid interferences. postpaid: O2 on Business XL; prepaid: DE: Aldi Talk, Lidl; UK: 3; BG: MTel, vivacom; RU: MTS; RS: MTS; UAE: du Tourist SIM; INT'L: toggle mobile VoIP: sipgate.de (German DID); sipgate.co.uk (British DID); ukddi.com (British DID); sipcall.ch (Swiss DID); megafon.bg (Bulgarian DID); InterVoip.com |
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(#3)
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Senior Member
Prepaid Expert
Posts: 197
Join Date: 26 Dec 2004
Location: Sheffield UK
Country:
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![]() DC-HSPA is - I think - only in Release 8 version at the moment Mr I - all is does is to double the data rates by doubling the bandwidth to 10 MHz (2×5 MHz).
In theory, DC-HSDPA can support up to 42.2 Mbps, but unlike HSPA, it does not need to rely on MIMO transmission. This is the key. My understandng is that Release 8 of DC-HSDPA can only operate on adjacent carriers, whilst Release 9 will allow the paired cells to operate on two different frequency bands. I was talking to a Three tech recently who said the carrier is testing Quad Channel - QC-HSPA! Obviously the spread spectrum nature of 3G / DC-HSPA in this context will result in packet quality degradation, but since it's one handset and one cell site controlling everything, it's not a MAJOR problem. What I was trying to say - sorry I didn't express myself clearly - is that two 3G transceivers placed side by side would hit packet quality problems - and since we're talking about handsets that are designed cheaply and based on older chip sets, having one 3G and one 2G transceiver in the same handset avoids any problems - and it's cheaper ![]() +Steve ![]() PO Box 1014, Sheffield S10 5YG, UK Home mobie: Telefonica O2 Other UK mobiles: 3, Vodafone, Virgin Foreign SIMs: Toggle (multi); Germany (Fonic); Poland (Orange PL); Skype: stevewgold |
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