New Orthogonal Codes for Direct Sequence CDMA Communications
Journal Title: International Journal of engineering Research and Applications - Year 2017, Vol 7, Issue 12
Abstract
From a long period Walsh codes and Gold codes have been used as a spread spectrum codes in Code Division Multiple Access (CDMA) communications because of their ease of generation than the efficiency of these codes. Drawback of these codes is that they are limited in number and in their lengths. In this paper, we relaxed linear phase requirements of Walsh code and new sets of Walsh-like nonlinear phase binary orthogonal user codes (transforms) are obtained for asynchronous and synchronous spread spectrum multiuser communications. We designed simulink model and performed algorithm using MATLAB (R2011a version) to obtain this newly proposed Walsh-like code set for multiuser spread-spectrum communications. We compared their performance with existing codes like Gold code and Walsh code families. Our comparisons include their time domain properties like autocorrelation and cross correlation along with bit error rate(BER) performances in additive white Gaussian noise(AWGN) for the synchronous and asynchronous DS-CDMA communications. We proved that the proposed binary user code family outperforms the Walsh codes significantly and they match in performance with the popular, nearly orthogonal Gold codes closely for asynchronous multiuser communications in additive white Gaussian noise (AWGN) channels. We present in this paper that there are a good number of such desirable code sets available in the binary sample space with different transform sizes. These new binary sets with good performance and flexible code lengths might help us to improve the spread spectrum multiplexing capabilities of future wire line and wireless CDMA communications systems. Index Terms: Additive white Gaussian noise (AWGN) channel, code division multiple access (CDMA), Gold sequences, orthogonal binary codes, Walsh sequences.
Authors and Affiliations
Sandip Buradkar, Shrikant Chamlate, Chandrashekhar Kurve
Keywords
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- EP ID EP393253
- DOI 10.9790/9622-0712066773
- Views 104
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