Title :
Shifted carrier-hopping prime codes for multicode keying in wavelength-time O-CDMA
Author :
Narimanov, Evgenii ; Kwong, Wing C. ; Yang, Guu-Chang ; Prucnal, PAul R.
Author_Institution :
Dept. of Electr. Eng., Princeton Univ., NJ, USA
Abstract :
In this paper, we study the use of shifted carrier-hopping prime codes (CHPC) for multicode keying in wavelength-time optical code-division multiple-access (O-CDMA) systems. By using the code\´s good properties of zero autocorrelation sidelobes and cross-correlation functions of at most one, each user is assigned M=2m shifted copies of its own code matrix to represent m data bits per symbol with minimal interference. The advantages of our scheme are that: 1) a lower baud rate O-CDMA system can now support a higher bit rate; 2) no network synchronization is required; 3) no M-fold increase in code cardinality is needed, as compared with standard M-code keying; 4) the numbers of optical encoders and decoders can be reduced from M to one per user, a major hardware cost savings; and 5) user code confidentiality is enhanced, as compared with the transmission of one code matrix for each data-bit one in conventional "on-off keying" O-CDMA schemes. Finally, our performance analysis shows that there is a tradeoff between the error probability and the choice of M.
Keywords :
code division multiple access; codes; error statistics; matrix algebra; M-code keying; code cardinality; code matrix; error probability; multicode keying; on-off keying; shifted carrier-hopping prime codes; wavelength-time OCDMA; wavelength-time optical code-division multiple-access; zero autocorrelation sidelobes; Autocorrelation; Bit rate; Code standards; Costs; Decoding; Hardware; Interference; Multiaccess communication; Optical fiber networks; Performance analysis; Multicode keying; optical code-division multiple-access (O-CDMA); optical codes; wavelength-hopping time-spreading;
Journal_Title :
Communications, IEEE Transactions on
DOI :
10.1109/TCOMM.2005.860041