Radio over fiber downlink design for spatial modulation and multi-set space-time shift-keying

Spatial Modulation (SM) and Multi-Set Space-Time Shift-Keying (MS-STSK) are capable of striking a flexible design trade-off between the multiplexing and diversity gains attained. These techniques can also be combined with beamfoming for the sake of supporting reliable millimeter wave (mmWave) communications. In this treatise, we propose an analogue Radio over Fiber (RoF) downlink network relying on SM and MS-STSK combined with beamforming and up-conversion to mmWave carrier frequencies, whilst using all-optical processing. In the proposed Analogue RoF (A-RoF) system, most of the digital processing of the baseband SM and MS-STSK is carried out by the Central Unit and the implicitly carried bits of SM/MSSTSK, such as the antenna index selection and dispersion matrix selection bits, are recovered by the remote radio head (RRH) of our A-RoF network for creating a multi-functional Multiple- Input Multiple-Output (MIMO) arrangement. As detailed in [1], the classic modulated bits are conveyed by the radio signal, without requiring any additional Analogue-to-Digital Conversion (ADC) and Digital-to-Analogue Conversion (DAC) before transmission from the antennas. Moreover, A-RoF-aided techniques are invoked for achieving optical processing aided beamforming and optical up-conversion to a mmWave carrier frequency. Thus, we invoke A-RoF techniques for the generation of our SM/MSSTSK signal with the aid of optically up-converted millimetre wave beamforming without using any electronic oscillators, mixers or phase shifters. Furthermore, our A-RoF-aided system’s BER performance is similar to the conventional all-electronic SM/MS-STSK scheme