MCPC in Satellite Communication and VSAT Technology

The term “Multiple Channels Per Carrier” or MCPC is widely used in satellite communication and VSAT technology.

All the channels are multiplexed before being modulated, as shown in the figure. TDM (Time Division Multiplexing) is used for multiplexing information from individual multiple channels into a serial frame of bits.

MCPC means multiple channels (i.e., voice and data channels) per RF carrier of a satellite transponder. As shown in the figure, 8 voice channels and 4 data channels are interfaced with a MUX (Multiplexer) and then modulated. Voice channels will have either 9.6 or 16 kbps of data rate. Data channels will have 2.4, 4.8, or 9.6 kbps of data rate. If all the voice channels are only active then 128kbps of the information bit rate is modulated on the RF carrier in the MODEM.

As shown in the figure, MCPC utilizes satellite resources efficiently, as multiple channels are multiplexed and transmitted on a single carrier of a transponder.

The voice line can be interfaced with EPABX/PBX. The data line is mainly used for file transfer or corporate email.

Advantages of MCPC

Following are the advantages of MCPC in satellite and VSAT technology:

1. MCPC allows multiple VSAT terminals to share the same carrier frequency, leading to more efficient use of available bandwidth.
2. MCPC enables dynamic allocation of bandwidth among multiple users, adapting to changing traffic patterns and accommodating varying data rate requirements.
3. Shared bandwidth in MCPC systems can be more cost-effective, especially in scenarios where dedicated and constant bandwidth is not required for each terminal.
4. MCPC is well-suited for point-to-multipoint communication, making it ideal for scenarios where a central hub communicates with multiple VSAT terminals.
5. MCPC systems provide flexibility in resource management, allowing for the efficient sharing of satellite transponder resources among multiple users.

Disadvantages of MCPC

Following are the disadvantages of MCPC in satellite communication:

1. In a shared environment, multiple VSAT terminals contend for the same carrier frequency, which may lead to potential contention issues during peak usage times under a dynamic allocation scenario.
2. The shared nature of the carrier frequency raises potential security concerns, as multiple users are transmitting and receiving signals on the same channel.
3. The dynamic nature of bandwidth allocation makes the performance less predictable compared to dedicated SCPC (Single Channel Per Carrier) systems.
4. MCPC may not be the best choice for applications that require a constant, dedicated, and high-reliability connection, such as certain mission-critical communications.

Conclusion

In summary, MCPC offers flexibility and cost efficiency in bandwidth usage, making it suitable for point-to-multipoint communication scenarios.