Title :
Modified Viterbi decoders for joint data detection and timing recovery of convolutionally encoded PPM and OPPM optical signals
Author :
Lai, Che-Hsi ; Kiasaleh, Kamran
Author_Institution :
Nokia Telecommun. Inc., Westlake, TX, USA
fDate :
1/1/1997 12:00:00 AM
Abstract :
Two novel Viterbi decoders, known as joint Viterbi decoder (JVD) and enhanced Viterbi decoder (EVD), for synchronization and data detection are introduced and analyzed for convolutionally-encoded (CE) optical pulse-position modulation (PPM) and overlapping PPM (OPPM) channels. For the JVD algorithm, a count metric is employed to perform the Viterbi decoding in the absence of synchronization. For the EVD algorithm, a memory array is utilized to reduce the computation time of the JVD algorithm. With the aid of a previously proposed upper-bound and taking advantage of the minimal asymptotic normalized timing error (MANTE) concept, approximate performance measures for the EVD and JVD receivers are obtained
Keywords :
Viterbi decoding; computational complexity; convolutional codes; optical communication; optical modulation; optical signal detection; pulse position modulation; telecommunication channels; timing; EVD algorithm; EVD receivers; JVD algorithm; JVD receivers; Viterbi decoding; approximate performance measures; computation time reduction; convolutionally encoded OPPM optical signals; convolutionally encoded PPM optical signals; count metric; enhanced Viterbi decoder; joint Viterbi decoder; joint data detection; memory array; minimal asymptotic normalized timing error; modified Viterbi decoders; optical communication; optical pulse position modulation; overlapping PPM channels; synchronization; timing recovery; upper bound; Convolution; Decoding; Optical modulation; Optical pulses; Optical receivers; Phase locked loops; Pulse modulation; Space vector pulse width modulation; Timing; Viterbi algorithm;
Journal_Title :
Communications, IEEE Transactions on
