Baron_Sengir said:
I'm sure this sounds like a really dumb question but can latency and download speed be improved with a better signal? I only get 2 bars on my card?
And secondly is there another simple alternative to boost the signal if it will improve speeds?
Thanks
Not dumb at all, actually 100% spot on.
To transmit data over radio frequencies at these crazy speeds (we can already achieve 1.8Mb/s!), you need to do very fancy modulation and encoding (M&C) of the data stream. The systems employ a number of different M&C techniques to accommodate different signal conditions. The better the signal (high level and no interference), the more complex the M&C can be.
For example, EDGE employs a range called MC4 to MC9 and will automatically select the best one based on the current conditions.
UMTS (3G and especially HSDPA) is the same.
So throughput is directly proportional to signal quality.
In addition to the above, there is another phenomenon called "cell breathing" which states the more users on a UMTS cell, the smaller the cell.
The cell does not physically shrink, but rather as more users operate in the cell, the conditions for everyone deteriorate and the ones with the worst signal conditions (i.e. at the edge of the cell) will drop off first.
Thus it appears that the cell shrinks and expands, i.e. it's "breathing".
It's obvious that you would want to get the best possible signal and the ultimate answer is to have enough base stations to give everyone the best possible signal. It's not so easy, however.
1) You need to find a site - Not nearly as easy as it sounds. Invariably someone objects to a new site.
2) You need lots of new sites with UMTS, many times more to cover the same area than with GSM. (currently we have 1600 3G base stations that cover about 16% of the country, compare with about 5000 base stations needed to give 98% coverage on GSM).
3) You need to plan the radio frequencies in such a way that it does not interfere (or be interfered) with all the neighbouring cells, the other cellular operators and anything else that might be transmitting in the area.
4) The site needs to be build which obviously takes resources (finance, man power, time).
You can see it's not so easy just to roll out a UMTS network and the criteria for selecting the next site is a combination of usage need (number of users, current load, etc.) plus all the above factors.
Thus Port Shepstone will be lower on the list than a Johannesburg suburb.
You can see the latest coverage on
www.vodacom.co.za.
If you don't have optimal coverage, or have good coverage but with lots of interference, you must try and get the best possible signal in your environment.
1) Increase signal level - Just moving indoors will drop the signal by at least 8dB, so try and have as little physical obstructions in the signal path.
There are a range of antennas available to boost the signal, from the simple clip-on supplied with the card, to the range available from Poynting. Their high-gain, externally mounted antenna works extremely well, especially if you work a lot in a fixed position, like your home or office.
You could also use the WiFi Router to allow you to move the 3G card to the best possible position, high up in a ceiling, for example.
2) Decrease interference - Make sure you don't have other transmitters close to your 3G card, WiFi access points, etc.
The better you make life for the 3G signal, the better your chances to get the best possible throughput.
Some forumites have gone to extreme measures to get a proper signal. I know of one laptop with a 3G card high up in a tree! Biometrics (I think) has got a tower that's a hazard to the local air traffic.
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