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SCPC vs iDirect

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Posts: 30
Jan 30th, 2008 at 7:44pm  
Can anyone shade more light on the advantage of SCPC over IDirect and iDirect over SCPC? Thanks for your anticipated response.
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Reply #1 - Feb 17th, 2008 at 3:59pm  
iDirect iSCPC and SCPC are nearly one in the same in the fact that they are both dedicated (committed) BW. 

iDirect iSCPC will allow the NO to tap the statistical and configuration control resources provided by the iDirect NMS. 

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Reply #2 - Mar 31st, 2008 at 5:27am  
I think he was looking for more of a difference between TDMA and SCPC.
iDirect (TDMA) is a satellite network that utilizes bursting time slots, from the remote to the hub, to send its data and allows multiple remotes to share the same bandwidth amongst each other. This can provide a huge cost savings. It allows major bandwidth providers (TCS, Intelsat, Segovia and others) to oversubscribe a satellite link just as the phone companies do.
SCPC (Single Channel Per Carrier) is a dedicated link between 2 satellite modems that cannot be shared even if the user is not using all of it at any one given time. The advantage of SCPC is found when a user requires dedicated video circuit (which require streaming and thus cannot take advantage of the bursting time slot) or have a heavy circuit load of VOIP phones.
As TDMAMike previously mentioned iDirect's modem are capable of iSCPC (SCPC) or TDMA with a simple software flash.
Hope this helps.
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Reply #3 - Jun 11th, 2009 at 8:14pm  
Comparison of Asymmetric SCPC and TDMA (iDirect)

How to Choose the Best Transmission Option for Your Rig Communications.

There’s not a competition between asymmetric SCPC and TDMA service types.  Each has their own strengths depending on the particular site communication needs.

SCPC (Single Channel Per Carrier) permits a dedicated two-way point-to-point VSAT transmission of voice, data and video.  TDMA (Time Division Multiple Access) is a communication technology that allows efficient shared two-way satellite IP transmission.

For an offshore requirement, the cost difference between using asymmetrical SCPC VSAT design and TDMA based solution is minimal, unless the TDMA solution compromises on the actual bandwidth (Committed Information Rates – CIR).

For offshore moveable rigs where reliability and quality of service are paramount, EMC recommends SCPC VSAT technology before TDMA based solutions.  SCPC solutions provide a higher performance level, better scalability, better security and improved control and remote manageability.

TDMA (iDirect) is a cost effective alternative for remote sites that have smaller scale communications requirement where there is a large number of sites able to share available bandwidth.  EMC provides a number of land rigs and static offshore production platforms with TDMA (IDirect) VSAT technology today.  Few companies, if any, have more experience in delivering modern communications capability with iDirect.

With hundreds of EMC VSAT rig installations worldwide, about 45% are utilizing iDirect TDMA technology and 55% are using SCPC technology.  EMC is uniquely qualified to offer its customers advice and recommendations in selecting the optimal VSAT solution to meet functional and operational requirements.

(Bandwidth Utilization)
Asymmetric SCPC      - No overhead.
- Multiple choices in coding technology.
- Overall 25% - 70% better utilization of bandwidth depending on coding rates chosen.

TDMA iDirect:
- 20% - 25% overhead on return channel.
- Limited coding available.
- Ability to over-subscribe bandwidth, several sites can utilize same bandwidth through NOT at the same time.

Asymmetric SCPC
- Slightly lower latency.
- Easy to control and manage

TDMA iDirect            
- Latency can increase significantly in an oversubscribed state.
- Great care required during link design to avoid latency problems.

Equipment Performance
Asymmetric SCPC      
- SCPC systems have been around for decades and are very robust.
- Made for high reliability links in smaller quantities.
- Hardware is controlled on an individual basis.
- Less complex system that scales easily.
- Proven.

TDMA iDirect      
- Focus on low cost, mass produced in high quantities, higher failure rates.  Higher end products evolved over last couple of years.
- Complicated management systems, software controlled.
- Hub control system carries significant investment.

Track Record
Asymmetric SCPC      
- Proven over decades.

TDMA iDirect      
- Newer, although maturing.

Asymmetric SCPC      
- Easy to measure network performance and speeds.

TDMA (iDirect)            
- Actual performance is more difficult to measure.

- By design, a TDMA system only proves useful in shared environments with many remote sites sharing limited bandwidth with sporadic usage patterns.

- Only by oversubscription will TDMA prove cost effective.

- In typical oil and gas applications, such as a number of rigs located in a limited geographical area, there tends to be a significant spike in traffic during early morning reporting time.  This traffic spike tends to happen at the same time and total available bandwidth needs to be sized according to this spike.  This will significantly limit the possibility to oversubscribe, as well as reduce the cost benefit with TDMA based solutions.

For more information on the best option for your remote site communications, contact EMC today.

Best Regards,
Stuart A. Guillot
Business Manager, Oil and Gas Vertical

799 Brickell Plaza 8th Fl
Miami, FL 33131 USA
T.  +1 305.539.1358 x 232
F.  +1 786.425.0679
M. +1 786.303.2350

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Best Regards,&&&&Stuart A. Guillot&&Business Manager, Oil and Gas Vertica
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