Does DC-HSDPA improve speeds on older handsets?

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Behodar

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Topic # 112295 4-Dec-2012 12:00

Hi,

I'm just wondering whether DC-HSDPA will help at all on my iPhone 4S. If I'm understanding it correctly, then there are essentially two networks running in parallel (obviously with plenty of shared equipment) which I'll call "A" and "B".

Without a DC network, all devices must connect to "A" since that's all there is. Obviously with DC, a DC-compatible device will connect to both "A" and "B".

My question is whether an older device, such as an iPhone 4S, is able to connect to the as-yet-uncongested "B" and therefore get a speed boost? Obviously it can't connect to "A" and "B" at the same time, but is it able to choose the least-congested network to connect to, or will it always connect to "A"?

Hopefully I've explained that clearly enough :)

nakedmolerat

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Reply # 726710 4-Dec-2012 12:03

I think the capacity of that cell site also increased, so you should see some improvement in term of the average speed.

johnr

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Reply # 726720 4-Dec-2012 12:13

Vodafone also have sites running Tri and quad carrier for extra capacity but these carriers are not bonded

Approx 250 sites running DC HSPA+ over NZ now and this number will grow to over 600 in the coming weeks before christmas

sbiddle

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Reply # 726852 4-Dec-2012 15:06

Dual Carrier is simply the capability to bond multiple carriers. Both Vodafone and Telecom have had multiple carriers running on cellsites for quite some time to improve capacity, but you need a dual carrier capable device to bond multiple carriers together.

Behodar

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Reply # 726863 4-Dec-2012 15:25

Thanks, I think I understand now. I'm just hoping for some better speeds at some point since Telecom's dropped from several Mb/s down to a fraction of that. Meanwhile I got 9.04 Mb/s last week when down in Turangi where there are obviously far fewer customers... but I'm getting a bit off topic now :)

LetMeHelpYou

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Reply # 736029 21-Dec-2012 14:25

DC-HSDPA will only not work with the iphone 4s as it is not a DC-HSDPA device. For DC-HSDPA to work, the device must support this capability and the cell site must have this feature activated and configured.

More details on DC-HSDPA can be found on a separate thread.

http://www.geekzone.co.nz/forums.asp?forumid=39&topicid=109900&page_no=2

johnr

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Reply # 736031 21-Dec-2012 14:27

http://www.geekzone.co.nz/forums.asp?forumid=39&topicid=109900&page_no=2

Behodar

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Reply # 736042 21-Dec-2012 14:41

The linked thread indicates that the RNC will distribute single-carrier devices over all available carriers (up to six), so the impression I got is that once another carrier is added to a given site then there should be a speed boost for all existing devices.

When I first posted this thread, I didn't realise that it was possible to have multiple carriers on the same site without DC. However, it's now clear to me that any DC site will by definition have at least two carriers and will therefore provide a performance boost if it previously only had one carrier.

In other words, if the local site currently has one carrier and is upgraded to DC, then I should see a performance benefit (due to RNC load balancing) despite not having a DC phone. Is that correct?

LetMeHelpYou

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Reply # 736070 21-Dec-2012 15:39

When another carrier is added to a site, there may be a speed improvement due to better load distribution/balancing across the carriers as the RF spectrum is a shared resource across data users on a specific carrier. So, if you are using non-DC phone, and a single carrier site got upgraded to a two carrier site (with or without DC-HSDPA carrier bonding activated), you generally will have better performance as there is now 2 carriers to service the same footprint.

Idea is

Without DC-HSDPA your 'throughput' speed is always served by a single carrier, iregardless of how many carriers the site has. How much throughput you get is largely affected by the load of that specific carrier.

With DC-HSDPA, your 'throughput' speed is served by two 'bonded' adjacent carriers.

That is why for iphone 4s, the max theoretical speed is normally advertised as 21 Mbps HSDPA+. (a single carrier can only pump out 21Mbps, iregardless of how many carrier it has, as the user is only served by a single carrier at any one time.

For the Iphone 5, it is normally marketed as being able to achieve 42 Mbps. (two carriers bonded, where a single user can be served by both carriers on a DC-HSDPA capable site)

Behodar

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Reply # 754471 1-Feb-2013 16:18

Telecom has now rolled out DC in my area... and I'm still getting the same old slow speeds. It looks like you really do need a DC-capable phone (either that, or there were already two separate carriers in the first place).

boby55

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Reply # 754494 1-Feb-2013 17:28

Behodar: Telecom has now rolled out DC in my area... and I'm still getting the same old slow speeds. It looks like you really do need a DC-capable phone (either that, or there were already two separate carriers in the first place).

I would say most sites already have sufficient bandwidth hence you won't see a large increase in performance without a DC phone