1. A satellite communication system comprising: a circularly-polarized (CP) terminal, at a receiving side of said satellite communication system, configured to concurrently receive data from a first terminal and a second terminal, at a transmitting side of said satellite communication system, through multiple linearly-polarized (LP) communication channels that are on a satellite and at a common frequency slot, wherein one of said linearly-polarized communication channels is configured to carry a first sum of a first signal, from said first terminal, weighted by a first parameter in a first weighting vector plus a second signal, from said second terminal, weighted by a second parameter in a second weighting vector and another one of said linearly-polarized communication channels is configured to carry a second sum of said first signal weighted by a third parameter in said first weighting vector plus said second signal weighted by a fourth parameter in said second weighting vector; and a polarization-realignment element at a downstream side of said circularly-polarized (CP) terminal at said receiving side of said satellite communication system.