Abstract: The satellite channel capacity depends on available bandwidth (Bw), transmit power, receiver sensitivity, sometimes referred as gain-to-noise temperature ratio (G/T), ambient noise density etc. The other parameters which dictate channel capacity are type of modulation scheme, access technique, use of FEC (forward error correction) technique, area illuminated by the satellite beam at a particular period of time, required probability of bit error rate, under identical assumption of channel conditions. Digital information transmission and reception is being considered for study and analysis purpose. The satcom. Network throughput optimization depends on many techniques like using proper Modulation scheme to optimally use the power equivalent bandwidth of the transponder, the frequency allocation to allot the central BW of transponder to location falling beyond 3 dB. BW contour, use of spot beams with on board satellite switching, adaptive bit rate to reduce the fade margins which sometimes are of the order of 10 dB. Or so. , appropriate access schemes like carrier-in-carrier (CnC), also called paired carrier multiple access (PCMA) for satellite where enough onboard power generation capability is available. Techniques like MIMO, which in the form of Dual-Circular polarization for one onboard antenna and multi antennas on ground stations fits best into requirement as on today’s limitations of satellite having constraints of less space, weight and available DC power still exists. MIMO is more suitable for Power limited satellite channel. The access techniques like TCP/IP accelerator, firewall, virtual private network (VPN), traffic shaping, intrusion prevention system (IPS) – antivirus/antispyware/antimalware, web filter and antispam for internet application will further optimize the capacity of a given satellite channel. Some of the techniques like modulation and FEC (Forward Error Correction), PCMA, frequency allocation for optimal communication can be implemented by configuration of modem or changing the itself but the few of them demand on board hardware change. These techniques are MIMO and SSTDMA Satellite Switched TDMA.
Keywords: PEMA, Paired Carrier Multiple Access, MIMO, Multi Input Multi Output, TCP, Transmission Control Protocol, EB/NO- Bit energy-to-noise Power spectral density, IP, Internet Protocol, PCMA, Power equivalent bandwidth