Transmission Channel Characteristics of Relay Dual-Polarization MIMO System for Hypersonic Vehicles Under Plasma Sheath

The blackout problem caused by plasma sheath is a serious obstacle to the communication system of hypersonic vehicles. The uplink relay transmission method is an effective means of mitigating serious attenuation caused by plasma sheath. This paper proposes a Ka-band
$2\times2$
dual-polarization multiple-input multiple-output (MIMO) scheme by adopting a left-/right-hand circular polarized antenna to increase channel capacity and signal quality. The relay dual-polarized MIMO channel model between the hypersonic vehicle and satellite is established by emphasizing the plasma sheath effect, especially the cross-polar coupling and polar correlation under plasma sheath. Useful numerical results on the relay dual-polarized MIMO ergodic channel capacity are analyzed. Thus, significant capacity gains with respect to the conventional single-input single-output case are illustrated based on this analysis. Simulation results show that the relay dual-polarized MIMO method can increase the channel ergodic capacity by 1.9–2 times under most circumstances, and the angle between the selected relay satellite and the vehicle normal direction should be minimal. This statistical channel model can be applied to the wireless communication system design and evaluation for hypersonic vehicles.