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UKSTEVE (Offline)
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Default 17-09-2013, 16:37

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.

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[size=2]Steve Gold
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);

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Default 18-09-2013, 20:59

Quote:
Originally Posted by UKSTEVE View Post
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.
If it actually was a problem to establish two separate radio links on adjacent UMTS frequencies from the same handset how could DC-HSPA work which does just the same to increase bandwidth? Integrating two 3G radio modules may be a cost-related problem for budget phones but I think there's no major technical issue at all.
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.


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UKSTEVE (Offline)
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Default 20-09-2013, 16:21

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


[size=2]Steve Gold
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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