A Study On The Error Performance Of Constant Envelope Modulation And PF Cooperative Systems

Joint transmit selection combining(SC)and receive maximum-ratio combining(MRC)antenna diversity can obtain high diversity ordersand improve the error performance of wireless communication systems significantly.Differentially encoded quadri-phase shift keying(DE-QPSK)modulation can overcome phase ambiguity.Error performance of DE-QPSK withjoint transmit SC and receive MRC antenna diversity over Nakagami fading channels isinvestigated in this paper.Constant envelope continuous phase frequency shift keying(CPFSK)modulation signal has an advantage over linear modulation because they can reduce linearity dependence on power amplifier and enable the use of inexpensive Class C power amplifier.The relaycan pick up the phase of receive signal and forward to the destinationwhen adopting phase-only forward(PF)protocol.PF is a much simplerstrategy than decode-and-forward(DF)protocoland amplify-and-forward(AF)protocol without resorting to intermediatedecoding and signal re-modulation.In this paper,error performance of multi-branchor multi-hopPF cooperative system,in conjunction with CPFSKmodulation and MRC receive diversity over time-selective Rayleigh fading channels,is investigated.Both cases ofwith and without antenna selection at the relaysare considered.Chapter lpresents a brief review of joint transmit and receive antenna diversity and constant envelopemodulation cooperative system.Chapter 2introducesprincipleof DE-QPSK modulation and demodulation firstly.Exact closed-form formulationand approximate closed-form formulationfor the average symbol error rate(ASER)of DE-QPSK with joint transmit and receive diversity in independent Nakagami fading channels and correlated Nakagami fading channelsare derived,respectively.Numerical and simulation results are presented to illustrate the effect of distributing the antennas over transmit and receiveside and fading parameterson the ASER of DE-QPSK.Chapter 3 investigates error performance of multi-branchor multi-hopPF cooperative systems involving CPFSKmodulation.Firstly,semi-analytical expressionsof multi-branchdual-hop PF and DF cooperative systemswith CPFSK modulation,one receive antenna in every relaying node and MRCreceive diversity are derived,respectively.Comparisons between PF and DFcooperative systems are presented.Next,semi-analytical ABERexpressionof multi-branchdual-hop PF cooperative systemswith CPFSK modulation,two receive antennas in every relaying node and MRC receive diversity is derived.Numerical evaluated results are plotted and compared with simulation results to verify the correctness of the derivations.Finally,semi-analyticalABER expressions ofmulti-hopPF cooperative systemsemploying CPFSK transmission,with and without antenna selection inrelaying nodes,are derived.Simulations are carried out to verify the analytical evaluations.Effect of relaying nodes' number,modulation coefficient and normalized doppler shiftonABER performance of PF cooperative systems are also illustrated.Chapter 4 is conclusion of this paper.