Learn More
Alamouti-type space-time block coding is studied for optical wireless communication systems using coherent detection over atmospheric turbulence channels. Atmospheric turbulence-induced fading and phase noise are known to impair the performance of coherent optical wireless systems. Two new Alamouti-type space-time coded architectures are proposed to(More)
Exact error rate performances are studied for coherent free-space optical communication systems under strong turbulence with diversity reception. Equal gain and selection diversity are considered as practical schemes to mitigate turbulence. The exact bit-error rate for binary phase-shift keying and outage probability are developed for equal gain diversity.(More)
A detailed analysis and comparison is carried out for optical wireless communications (OWCs) with coherent and subcarrier-intensity-modulation-based systems, which are the two major implementations for detection-threshold-free operation without irreducible error floors. Error rate performance is studied for communications with binary phase-shift keying,(More)
Coherent wireless optical communication systems with heterodyne detection are analyzed for binary phase-shift keying (BPSK), differential PSK (DPSK), and M-ary PSK over Gamma-Gamma turbulence channels. Closed-form error rate expressions are derived using a series expansion approach. It is shown that, in the special case of K-distributed turbulence channel,(More)
A coherent multiple-input multiple-output architecture is proposed for optical wireless communications (OWCs) to mitigate atmospheric turbulence effects. Transmitter optical signals operate at distinct carrier frequencies to allow the received optical signals to be separately processed. The accumulated phase noise in each transmission branch can then be(More)
Wireless optical communication systems with coherent detection are analyzed for Gamma-Gamma distributed turbulence channels. In addition to the shot noise, we consider the impacts of both turbulence amplitude fluctuations and phase fluctuations on the error performance. Error rate analyses of predetection and postdetection equal gain combining (EGC) are(More)