An Improved Algorithm for PAPR Reduction of OFDM Systems - Advanced Research on Computer Education, Simulation and Modeling - page 376

4.3 L Value Comparison

The PAPR performance of hybrid algorithm is displayed in fig. 6. The simulation result
is presented when the subcarriers is 64 and the modulation mode is QPSK for L=4, 8,
16 and 32.
From the Fig. 6, it can be seen the performance of algorithm can gradually improve
with increasing L value, for CCDF = , when L=4, 8, 16 and 32, and the threshold

PAPR 0 are 4.50dB, 4.43dB, 4.33dB and 4.25dB, respectively. But with continuous
increasing L, the system performance improvement is not obvious.

4

10

10 0

-1

10

10 -2

-3

10

L=4
L=8
L=16
L=32

10 -4

-5

10

0 1 2 3 4 5

PAPR(dB)

Fig. 6. Comparison of PAPR performance with different value of L

4.4 The Modulation Mode Comparison

Considering the different modulation modes, the performance of hybrid algorithm is
shown in Fig. 7, which shows the CCDF performance of the OFDM system using
BPSK, QPSK, QAM and 16QAM, respectively.
From Fig. 7, it is clear that PAPR performance of the hybrid algorithm is almost the
same with different modulation modes. It is that the choice of modulation has little
effect on the PAPR value. Without considering other factors, we can choose subcarrier
modulation mode with freedom and consider the data transmission rate.

10 0

-1

10

-2

10

Init ial ofdm
BP SK L =1 6
QP SK L=16
QAM L=16
16QA M L=16

10 -3

10 -4

0 2 4 6 8 10 12

PAPR(dB)

Fig. 7. Comparison of PAPR performance with different modulation