A Novel Multi-User Space-Time Block Coding based Superposition Transmission for Future Generation Wireless Networks

The present study proposes a novel multi-user transmission scheme, which employs the utilization of space-time block coding (STBC) in conjunction with orthogonal frequency division multiplexing (OFDM) as the transmission framework. The scheme, referred to as multi-user STBC super-positioned transmission (MU-STBC-ST), utilizes the superposition of user data to serve multiple users with spectral, temporal, and frequency resources similar to non-orthogonal multiplexing. Furthermore, the proposed scheme is deployed in conjunction with multiple-input multiple-output (MIMO) transmission to serve two users, resulting in an improved version of STBC-MIMO. To achieve this, we employ the utilization of uniquely designed auxiliary signals that are superimposed on top of already super-positioned user data during the two transmission slots, with the objective of intelligently canceling the inter-user interference and channel effects at the receiver, while simultaneously making the reception process much simpler, energy-efficient and less power-draining. Additionally, we also propose a simple equalization policy to recover the signals at the receiver while reducing complexity significantly, resulting in low latency and less processing at the receiver. The proposed scheme's performance is evaluated through computer simulation utilizing performance metrics such as bit error rate (BER), throughput error rate (TER), and peak-to-average power ratio (PAPR) and compared with that of conventional STBC.