Modified Active Constellation Extension Algorithm for PAPR Reduction in OFDM Systems

PAPR Reduction in OFDM Signals by Self-Adjustment Gain Method

“…The proposed method does not require the performance of iterations, and hence saves computational costs. Threes schemes that are relevant to the ACE involved with the constellation rules, i.e., the projection onto the convex set (ACE-POCS), the smart gradient projection (ACE-SGP), and the modified ACE (mACE) [38][39][40][41], are considered for comparison with the PAPR reduction performance. Tables 2 and 3 show the PAPR reduction performance for various schemes at the third iteration, compared to the proposed SAG scheme for QPSK-OFDM and 16QAM-OFDM, respectively, at CCDF = 10 −4 .…”

“…However, searching for these proper values usually requires a large computational complexity. The scheme of non-bijective constellations [31][32][33][34][35][36][37][38][39][40] tries to alter or introduce new constellations to combat large signal peaks, such as the active constellation extension (ACE) [31] method, which reduces the PAPR by changing the signal constellation, while preserving the same minimum distance. The distortion-type technologies include clipping [41][42][43][44], which is the simplest method, by clipping the peak amplitude of the OFDM signal to some desired maximum level, at the price of introducing in-band distortion and out-of-band radiation.…”

“…The algorithm of the active constellation extension, with a projection onto convex sets (ACE-POCS), adjusts the signal amplitude and phase for increasing the average power, following the minimax rule to attain the optimum effect [37,38]. By combining the self-adaption clipping strategy and special extension rules, the extension projection onto convex sets (ACE-EPOCS) designed the correction factor to adjust the scheme for its flexibility [38,39]. To reform the active constellation extension, a pre-distortion scheme, by defining expendable regions, was proposed for reducing the PAPR with only one iteration [40].…”

Hybrid Energy Efficiency Friendly Frequency Domain TR Algorithm Based on PSO Algorithm Evaluated by Novel Maximizing HPA Efficiency Evaluation Criteria

“…For class B and class A non-ideal HPAs, the typical value of β is 0.5 and 1, respectively. From (14), it has known that the efficiency of HPA decreases with the decline of HPA output power. Modulation error rate (MER) is a significant criterion for measuring signal quality by quantifying signal to noise ratio (SDR), defined as the ratio of the received symbol location and the difference between received symbol location and ideal one.…”

“…However, due to the low probability of peak value appearance, CCDF improvement does not necessarily imply optimising PA efficiency. Signal peak can be optimization with a variety of approaches and schemes: clipping and filtering (CF) [8]; coding [9]; adaptive symbol selection [10]; partial transmit sequence (PTS) [11] and interleaving [12]; tone reservation/injection [13]; active signal constellation extension (ACE) [14], companding, and so forth [15]. Predistortion and coding schemes are no longer sufficient for modern communication systems; he tone distortion algorithm is considered one of the most potential approaches.…”