An Overview of Indoor OFDM/DMT Optical Wireless Communication Systems. Speaker: Shao- Ci Jheng Advisor: Dr. Ho-Ting Wu 2013/12/23. Outline. Background Introduction Optical Wireless OFDM Techniques Half-wave symmetry OFDM techniques DC-biased OFDM techniques Results Conclusions
An Overview of Indoor OFDM/DMT Optical Wireless Communication Systems
Advisor: Dr. Ho-Ting Wu
high data rates in the order of Gbit/s can be achieved
but the system is vulnerable to blockage/shadowing becauseof its directionality.
several paths from source to receiver exist, which makes the system robust to blockage/shadowing.
However, the path losses are high and multi-paths create inter-symbol interference (ISI) which limits the achievable data rate.
q(k) : raw data bits are to be transmitted over the optical channel
data vector x (k): modulation using QAM, PAM, or phase shift keying(PSK) maps
the bits to data symbols and arrange
N: number of available subcarriers
B: the channel bandwidth
x *(N -k) is the complex conjugate transpose of the input data vector x (k)
Ng : number ofguard subcarriers
m = log(M)
M : thesize of the considered constellation diagram
The data rate of DC-OFDM system can be calculated using the same equation given in (3).