Agile MU-MIMO in congested environments with robust channel estimation

Abstract

This paper proposes a novel multi-user multiple-input and multiple-output (MU-MIMO) selection and beam-forming technique for a geosynchronous orbit (GSO) satellite communication (SATCOM) system. The MU-MIMO technique employs beam-forming and adaptive power allocation schemes in order to support a large numbers of users. Additionally, this paper provides a solution for the scenario where satellite ground terminals and cellular users are sharing the same spectrum band. The proposed MU-MIMO Selection And Beamforming (SAB) method makes it possible to constrain the interference created by a high powered satellite transponder, in order to maintain normal transceiving activity for commercial cellular users. Meanwhile the quality of service (QoS) is also satisfied for ground terminals. If the options of selectively serving certain users is available, the performance can be improved further in terms of constraining the interference level. The other novelty of this work is a robust channel estimation design to support the proposed MU-MIMO schemes with specifies the pilot structure design, such as the determination of proper pilot length and transmission power. Extensive simulation and numerical results illustrate and validate the theoretical development.