  This paper presents the novel application of Polarized Modulation (PMod) for
increasing the throughput in mobile satellite transmissions. One of the major
drawbacks in mobile satellite communications is the fact that the power budget
is often restrictive, making unaffordable to improve the spectral efficiency
without an increment of transmitted power. By using dual polarized antennas in
the transmitter and receiver, the PMod technique achieves an improvement in
throughput of up to $100$\% with respect to existing deployments, with an
increase of less than $1$ dB at low \ebn regime. Additionally, the proposed
scheme implies minimum hardware modifications with respect to the existing dual
polarized systems and does not require additional channel state information at
the transmitter; thus it can be used in current deployments. Demodulation (i.e.
detection and decoding) alternatives, with different processing complexity and
performance, are studied. The results are validated in a typical mobile
interactive scenario, the newest version of TS 102 744 standard (Broadband
Global Area Network (BGAN)), which aims to provide interactive mobile satellite
communications.
