Title :
A multilevel modulation scheme for high-speed wireless infrared communications
Author :
Hranilovic, Steve ; Johns, David A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Toronto Univ., Ont., Canada
Abstract :
To investigate short-distance, point-to-point, infrared channels, a test-bench and circuits were constructed to determine the limitations of existing optoelectronics. The results of these measurements are used to formulate a channel model which is employed for the subsequent analysis of candidate bandwidth efficient modulation schemes. A new multilevel modulation scheme, Adaptively Biased QAM (AB-QAM), is proposed which has an asymptotic 3 dB SNR improvement over PAM and a 4.5 dB improvement over QAM for large constellations while maintaining the same bandwidth efficiency. Expressions are derived for the performance of each modulation scheme and are verified in simulation
Keywords :
adaptive modulation; optical communication; optical modulation; quadrature amplitude modulation; telecommunication channels; SNR; adaptively biased QAM; bandwidth efficiency; constellation; free-space optical communication; high-speed wireless infrared communication; multilevel modulation; optoelectronic circuit; short-distance point-to-point channel model; simulation; Bandwidth; Circuits; High speed optical techniques; Intensity modulation; Optical fiber communication; Optical modulation; Optical signal processing; Photodiodes; Quadrature amplitude modulation; Wireless communication;
Conference_Titel :
Circuits and Systems, 1999. ISCAS '99. Proceedings of the 1999 IEEE International Symposium on
Conference_Location :
Orlando, FL
Print_ISBN :
0-7803-5471-0
DOI :
10.1109/ISCAS.1999.780164
