SISO and MISO Architecture Investigation for Wireless Optical OFDM Transmission

Abstract

As the need for demanding communication applications is increasing, the high speed connectivity has become a very significant issue. Thus, the study of optical wireless communication systems can lead to more efficient transmission schemes and techniques that will allow a high capacity bandwidth along with low bit-error-rate (BER). Moreover, the use of a bandwidth efficient signal modulation scheme like orthogonal frequency division modulation (OFDM) has provided the basis to compete with established wireless transmission schemes. In this work, we investigate the performance of an optical wireless link using a visible light laser beam at 680 nm with, both, single-input-singleoutput (SiSo) and multiple-input-single-output (MiSo) transmission topologies. We evaluate in practice the performance of the link with respect to BER and data rate achieved for an increasing number of subcarriers (64, 128, 256) and with various subcarrier modulation schemes (BPSK, QPSK and 16-QAM). The system gives very good results for non-coded transmission reaching up to 250 Mbit/s with a BER of 10−3. In practice, this value is fully acceptable due to the fact that a BER of up to 10−7 in commercial wireless optical systems (e.g., Wi-Fi, WiMAX, etc.) introducing coding at the lower network layer could be thus envisaged.