I work for a very very small municipality (500 catv subs and 130 internet subs) Until recently I was split between the water department and doing cable connects and internet installs. I have now been upgraded to working in the headend. I am not up on all the lingo and am Just trying to learn. We are currently using 2 ds channels and 4 us (qam16) channels to deliver internet to customers, we are still very much an analog system with about 64 catv channels on a 550mhz system. We currently only purchase 60mb of bandwidth from a provider. We currently provide internet at 3mbps, 2mbps, 1mbps for ds. We would like to able to upgrade it to 15/3 per customer. However we currently have some slightly cruddy snr averaging 26 - 27, we are currently tracking down noise on our system, though we think most of it is in the headend as we have a bunch of old drakes and we are phasing them out. We would. Current ds channels are 98, 99.
How many channels would we need to add to deliver 15/3 to 200 customers without there being a problem of slowing connections? What else can we do besides going to 256qam to improve bandwidth on our system? Any advice or information you can share that would help me understand this would be greatly appreciated.
there's allot to consider. first what cmts do you currently use?
do you use fiber or just coax? asking because the long cascades tend to have have more signal to noise and delays.
downstream ber or bit error rate and signal to noise. what does the average customer get on the downstream side?
Upstream, what's the channel width? with an SNR above 21, you can do 16Qam for modulation. after docsis overhead, it's around 7 Mbps shared bandwidth. how many upstream ports does the cmts have?
Cable modems, are they 2.0 or 3.0 modems?
Carl
I can't be be much help on how many channels it would take because customer usage varies quite a bit from one place to the next. If there is no fiber in the system then adding one additional channel would at least let you max out your upstream pipe. Having said that, 200 15mbs subs on a 27 or even 38 meg pipe is going to be a pain in my opinion. You would need a massive amount of channels to keep things from slowing to a crawl on netflix night. I will say that getting to 256qam should be high up on the priority list as it is a much more efficient use of hardware and bandwidth. If you think the snr problem is in the headend then check all the levels and make sure everything is set up correctly. Try to get your hands on a spectrum analyzer and see if you can track down the noise problem to one or two pieces of equipment.