Improvement on bit-error-rate performance of DS-CDMA by employing 4-elliptical phase shift keying

Abstract

Some modtilation schemes with the general name of Elliptical Modulation Scheme.s, have been propused and evahtated, in terms of Bit-Ervor-Rate (BER) performance. name[\, are Eccentricity Shifr Keving (ESK), Inclination Angle Shift Keyinz (IASK). Rotation Freqriency Shlfi Keying (RFSK) and Elliptical Phase Shft Keying (EPSK). Based on their advantages over &sting modiilation schemes. this paper aimed to confirm the contvihiitions of 4-EPSK, one of Elliptical Modulation Schemes with 2-bit in?ur.mation tvan.smi.ssion capability, to the improvement uf CDMA commrmication systems. In the paper, we investigated the possible applications of 4-EPSK to CDMA systems. through evahiating BER performance of synchronous DS-CDMA by employing 4-EPSK a~ its mod2ilation scheme, with an M-sequence ar7d an orthogonal Gold sequence respectively, along with comparison to that of DS-CDMA by employing QPSK: simiilation restilts have been achieved based on changeable nrimber of zi.ser.s, under A WGN and flat Rayleigli .fading ernironmen/ respectively. Advantage.s of DS-CDMA -4-EPSK over e.risting DS-CDMA-QPSK achieved in .sim~ilatiims, implies that 1 7 ~ , employi~g 4-EPSK as its modrrlatiun scheme. CDMA swtems can be improved it? terms of BER per:jormauce.