New Multi Level Spreading Codes for DS CDMA Communication
K. USHA, K. JAYA SANKAR
Available Online April 2013.
- Spreading codes are used to distinguish users and spread the signal to occupy much wider band width than the minimum required band width. Spreading codes are also called as user codes. Walsh, Gold and Kasami codes are the popularly used Binary (2-level) user codes. This paper proposes new multi level spreading codes constructed using ternary and quaternary Gray and Inverse Gray codes for multiuser Direct Sequence Code Division Multiple Access systems. Multi level spreading codes discussed in this paper are non zero mean, varying power codes. An attempt is made to analyze these multi level user codes through correlation properties. The methodology explained in this paper allows to generate 3-level user codes of length-6 and 4-level user codes of length-8. It also allows generation of codes whose lengths are even multiples of the codes of length 6 and length 8. The auto and cross correlation properties and bit error rate performance of these codes and their comparison with those of Walsh and Gold codes are presented in this paper.
- Open Access
- This is an open access article distributed under the CC BY-NC license.