Question for ProAsm

TheRoDent

TheRoDent

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Don't know if you'll be willing to answer this, but from the IPWireless nodeB product specifications I see that there are two types of rackmount NodeB's, a "High Capacity" and a "Low Capacity" version. http://www.ipwireless.com/pdfs/node_b.pdf

The Low capacity version can drive three sectors, but uses a single Baseband shelf for the signalling.

Which have Sentech deployed, and if it is the low capacity version, are there plans to upgrade them to the high capacity versions in high-density areas such as Joburg?

Secondly, is this the reason why some of the towers are underperforming?



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just to chip in here (as always) and to keep the topic fresh, I see that in the pdf they mention the peak throughput (thus, not sustained) of the nodeB as 36 Mbps in a best case scenario. Its probably unlikely that Sentech have opted for the most expensive high capacity solution from the get-go so its probably the 12Mbps version.

My concern is that 36Mbps sets a ceiling of about 550 users per tower (giving each user about 64kbps). Now 550 is a very low number IMO so what are they going to do to address this?

12Mbps @ 10:1 = about 950 users with 12.8Kbps each. Lovely..! And yes I know thats if everyone maxes out.. but its still not good.

Or is my understanding of the technology incorrect? I sure hope so otherwise this is bad news..
 
Your calculations, I believe are basically on par. It's all about how many baseband units there are.

3 sectors + 1 baseband unit = less signal processing, which gives us the 12Mb/s max.

3 sectors + 3 basebands units = 36Mb/s which sounds much better. I'm sure Sentech went for the low capacity version in areas where they haven't had much response, but I believe that most of the Joburg towers warrant the 3 baseband unit system.

1 basedband unit doing signal processing could also be the cause of a the bit of latency we're getting right?



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Sentech do not use any Rack mounted NodeB's.
They are all the outside single Sector NodeB's and are all high capacity.
Greedy with your calculations, think about it - how big do you think the total internet bandwidth is with 25 million odd users.


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If IPW's data is correct (available on the web) almost the entire current user
base of MW in SA would be able to cope on a single sector of a tower!!!
(2000 users). This was the designed capability from what I remember reading.

Edit: Please note I'm not talking Internet bandwidth here![:D]

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Thanx for that ProASM ... As always ;-)

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Thanks for the response ProAsm. I'd assumed you guys were using the rackmounts since you have those el-neato fridgedaire boxes to host all the kit in, and using a "outside" nodeB would then be a bit silly, since you have environmental control inside the boxes (thought I saw an aircon hanging off the side [:)] ).

But thanks for clearing that up.

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Well, I know that the bandwidth is fairly limited for our 25 million users or whatever (Africa I assume) or at leasted, capped significantly.. But my point is that we dont need a bottleneck within the last mile.. especially if this thing takes off as we all expect. Its all fine and well buying bandwidth etc but if each tower can only sustain 12 or even 36Mbps then thats an upper limit on scalability. It is definitely true that 36Mbps is a hell of a lot of bandwidth even in SAT-3 terms but say in 18 months time (or longer) when MyWireless enjoys the kind of penetration of say DSTV then you will be looking at hundreds of people on each tower. Now by doing the math, with say 1000 people (very dense area) on a single tower sharing 36Mbps means you have 36Kbps each for a total cost of minimum 1000*R650(excluding 256'ers etc and inflation) equates to R650000. Now lets assume 40% of that goes to bandwidth, that means there is R260000 to pay for 36Mbps of bandwidth (I dont know Telkoms rates but I guess its a lot more expensive than that for 36Mbps)

Anyways.. just my thoughts on the potential scalability. Im sure by then, the dense areas will have multi-tower coverage anyway.
 
Bandwidth works out as follows -

To land 1-1 international on the SAT3 costs between 5000-8000 depending on where its routing internationaly UK, USA, Japan etc. As well as where you land the bandwidth JHB, Capetown etc. And local costs around R 600 - 800 per 64k, using these figures, no ISP in SA could offer 512k solution at 1400 pm with out it being heavliy contended, assuming that 20% of it gets cached.

Keep Surfing
 
To Add, this is why telkom caps the international on ADSL and not local, as local costs nothing, especialy to them, while international costs big time and thats even directly to Telkom !

Keep Surfing
 
TheRoDent, yes one would assume using Rackmounts, but think of it, you now need a rack, and there are many rules and safety standards and regulations involved in using a rack. Also with a rack you need to get to to both at the back as well as the front and imagine that in the 'fridge' container where currently there is already not enough room to swing a mouse let alone a cat [:)]
Many of our own Towers, including several water towers are very high meaning long cable runs and the max feasible length is 30 meters of 7/8 or 60 meters of 1 5/8, thus in many cases the NodeB's sit halfway up the Tower connected to the ground equipment via cat5.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">thought I saw an aircon hanging off the side<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Correct, including a high powerered DC fan on the other side incase the aircon fries. [:)]



<hr noshade size="1"><center><font color="blue">MyWireless Stuff</font id="blue">
<font size="1"><font color="black">The opinions expressed here are mine alone and do not necessarily reflect the opinions of my employer</font id="size1"></font id="black"></center>
 
i love racks, especially big ones like pamela anderson has

Dean, care to explain how the contended thingy works more in depth? Lets say I have an ISP that sells 512k user accounts, what kind of b/w would i need etc? And why do my company pay a *** load of cash for 512k, where they can spend what you mentioned here on 1:1 international??

Why do you have to "put your two cents in"... but it's only a "penny for your thoughts"? Where's that extra penny going to?
 
PROASM: How do the towers connect to the main service (IE from tower to jhb) ? Hardwire?

Save a horney friend........

Durban Mal Park(36) 53% sig 128k
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by noone</i>
<br />i love racks, especially big ones like pamela anderson has

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Muhahahaha [:D]

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Rhino, all towers connect via Microwave in either 3.5g, 5.8g or 13g and bandwidth ranges from 35 to 155 mbits depending on the grid size.


<hr noshade size="1"><center><font color="blue">MyWireless Stuff</font id="blue">
<font size="1"><font color="black">The opinions expressed here are mine alone and do not necessarily reflect the opinions of my employer</font id="size1"></font id="black"></center>
 
Ah ic. do they connect to the main jhb hub, or to the towers in your garden :)

Save a horney friend........

Durban Mal Park(36) 53% sig 128k
 
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