**5.1. CCDF performance**

Figure 14 shows the performance improvement of the proposed system over a conventional system, i.e., without PAPR reduction, for the µ- law for different value of µ using 16 QAM signal mapping. At the probability of 10-3, the PAPR is almost 1.1 dB, 2.55 dB, 4 dB and 4.5 dB smaller than conventional system, for µ=2, µ=4, µ=13 and µ=64, respectively. The same results are obtained when A-law is considered. Figure 15 shows the CCDF performance of the companding method at µ=13 compared with that of the system that is used clipping technique for reduction where CR = 2.

Figures 16 and 17 show the improvements which are obtained when 64 QAM and QPSK modulation are used, respectively.

<sup>0</sup> <sup>2</sup> <sup>4</sup> <sup>6</sup> <sup>8</sup> <sup>10</sup> <sup>12</sup> <sup>14</sup> 10-3

PAPR0 [dB]

0 2 4 6 8 10 12 14

PAPR0 [dB]

Figure 22 shows the system performance over AWGN only, where the amount of improvement in SNR is 10.7 dB at BER=10-4 than the conventional system. The BER performance of the companding method compared with the system that is used clipping technique where CR = 2

Conventional With companding,µ=13 With clipping,CR=2 With companding,µ=4

PAPR Reduction in WiMAX System http://dx.doi.org/10.5772/55380 53

Conventional With companding,µ=4 With companding,µ=13

10-2

**Figure 15.** CCDF Performance comparisons with 16QAM.

100

10-3

and CR=1.4 is shown in Figure 23.

**Figure 16.** CCDF of PAPR with the proposed system (64QAM).

10-2

CCDF

10-1

CCDF

10-1

100
