'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
In this communication we consider the use of PPM
based modulation methods, such as the hybrid modulation
method called Amplitude and Pulse-Position Modulation
(APPM) and Overlapping Pulse-Position Modulation
(OPPM), to improve the performance of Infrared
WLAN’s. The bandwidth eficiency expressions of these
modulation schemes are presented and compared against
the one of Pulse-Position Modulation (PPM), which
allows to conclude that both APPM and OPPM can be
used to improve the performance of PPM without
significant bandwidth expansion, using Trellis-Coded
Modulation (TCM) codes. We also derive the best codes
for some APPM and OPPM schemes, and the results
show that non-negligible coding gains without bandwidth
expansion can be obtained with trellis codes of moderate
complexity