First Hardware Implementation of an SSK MIMO System With no RF-Chain at the Transmitter

This article presents the hardware implementation of a space shift keying (SSK) multiple-input multiple-output (MIMO) system with no radio frequency (RF)-chain at the transmitter. The transmitter design was solely based on RF-switches. SSK relays information strictly through spatial symbols and does not require the generation of any modulated symbol. It has been always anticipated in literature that SSK can be implemented with a single or no RF chain, but the physical realizations were never accomplished. This work demonstrates a 4 × 2 and 2 × 2 MIMO implementation of an SSK system using commercial-off-the-shelf (COTS) RF-switches. As a result, the achieved implementation paves the way towards commercial deployments of space modulation techniques. A detailed discussion of the hardware implementation is presented and results reveal an accurate match with theoretical SSK results over a Rician fading channel with variant Rician K- factors.