Space-time coded multi-transmission among distributed transmitters without perfect synchronization

For mobile users without antenna arrays, transmission diversity can be achieved with cooperative space-time encoded transmissions. However, a challenge is the lack of perfect synchronization on delay, timing and carrier frequency of distributed transmitters, which destroys the required space-time signal structure. In this letter, a new transmission scheme is proposed which employs distributed space-time block codes to achieve full diversity while tolerating imperfect synchronization. It is promising in distributed wireless networks such as sensor networks both to enhance transmission energy efficiency and to reduce synchronization cost.