What is SCPC satellite communication?
SCPC (Single Channel Per Carrier) is a satellite communication technology where each carrier is assigned to a single source. This means you get dedicated, fixed, continuous bandwidth — nobody else shares your carrier. If you have a 10 Mbps SCPC link, you always have 10 Mbps, regardless of how many other users are on the satellite.
SCPC is the preferred technology for applications that need predictable, guaranteed throughput: satellite radio, voice telephony, VPN connectivity, banking transactions, and critical infrastructure monitoring. The trade-off is cost — dedicated bandwidth is more expensive than shared. SCPC is used in iDirect technology deployments and is the standard for enterprise and government VSAT in Pakistan.
What is TDMA satellite communication?
TDMA (Time Division Multiple Access) divides a single carrier's bandwidth into time slots. Multiple users share the same carrier, each transmitting in their assigned time slot. This is more bandwidth-efficient and cheaper than SCPC because the satellite's capacity is shared among many users.
The downside is contention. When many users transmit simultaneously, each gets less effective bandwidth. TDMA systems use dynamic bandwidth allocation to mitigate this — giving more time slots to users who need them — but peak throughput is never guaranteed. Standard YahClick consumer and small-business plans use TDMA.
SCPC vs TDMA comparison
Here's how the two technologies compare for Pakistani business use cases:
| Criterion | SCPC | TDMA |
|---|---|---|
| Bandwidth | Dedicated, fixed | Shared, variable |
| Throughput guarantee | Yes — always full rate | No — subject to contention |
| Latency consistency | Consistent | Variable under load |
| Cost | Higher (dedicated) | Lower (shared) |
| Best for | Voice, VPN, banking, critical apps | Internet browsing, email, general use |
| Technology | iDirect, dedicated carriers | YahClick standard plans |
| Scalability | Per-carrier addition | Dynamic allocation within pool |
| CIR (Committed Info Rate) | Guaranteed | Best-effort with CIR option |
Which should you choose in Pakistan?
Choose SCPC if: you run VoIP or IP PBX over satellite (voice needs consistent latency), you have banking or financial transactions requiring guaranteed throughput, you operate critical infrastructure (NBP, OGDCL, government), or you need a CIR (Committed Information Rate) that never degrades. SCPC is the standard for enterprise and government VSAT in Pakistan.
Choose TDMA if: you need general internet access for browsing, email, and web applications, your bandwidth needs are bursty (occasional high usage, mostly low), or budget is the primary constraint. Standard YahClick business plans (PKR 8,000–30,000/month) use TDMA and are sufficient for most SME needs.
For AJK and northern Pakistan specifically: SCPC is recommended for remote government offices, hospitals, and critical sites where terrestrial internet is unavailable and the VSAT link is the primary (not backup) connectivity. The mountainous terrain means no fiber fallback — your satellite link must be reliable.
YahClick and the PAKSAT-1R migration in 2026
Pakistan's domestic satellite PAKSAT-1R reached end-of-life in 2026. The replacement PAKSAT-MM1 did not have sufficient Ku-band or Ka-band capacity available for commercial users — the Ka-band capacity was already committed to Kacific (a Singapore-based operator), and the Ku-band option would have required terminal equipment replacement at approximately 500 sites.
As a result, Pak Datacom migrated satellite connectivity for National Bank of Pakistan (400 branches), OGDCL, and AGPR from PAKSAT to YahClick (Yahsat/UAE with Hughes technology). This migration was approved by the Board of Directors and reported to the Ministry of IT and Telecommunication. YahClick now offers the best satellite broadband coverage and throughput for Pakistan, particularly in underserved areas like AJK.
The YahClick satellite architecture follows this path: your Server → Satellite Modem → Switch → 1.2M Antenna → Satellite → Ku-Band Hub Earthstation → Superdirect Hub → Internet / Supernet Corporate Network. We handle the full chain — equipment supply, installation, configuration, and ongoing monitoring.
Hybrid WAN: VSAT + terrestrial with failover
For mission-critical sites, we recommend hybrid WAN design — combining VSAT with terrestrial or wireless connectivity and automatic failover. If the primary link (terrestrial) fails, traffic automatically routes to VSAT (satellite) without interruption. This eliminates the single point of failure that pure VSAT or pure terrestrial deployments suffer from.
Hybrid WAN design adds PKR 20,000–50,000 in equipment and configuration but is essential for sites where connectivity downtime costs more than the redundancy equipment. In AJK, where terrestrial internet is unreliable and fiber cuts are common, hybrid WAN is the standard for government and enterprise deployments.