PAPR reduction of multi‐carrier systems with simple nonlinear companding transform

Abstract

A simple nonlinear companding transform which makes full use of the statistical characteristics of the original multi-carrier signals and combining them with the simplest clipping theory is proposed to reduce the peak-to-average power ratio (PAPR) of multi-carrier systems. By making a simple truncation to the Rayleigh-distributed original signals, the proposed scheme not only has low implementation complexity but also outperforms conventional companding schemes.

A Simplified Scheme of Estimation and Cancellation of Companding Noise for Companded Multicarrier Transmission Systems

“…1), is equipped with several conventional operations at the receiver, including conventional decompanding (DC) [13], [14], [15], [16], [20], no decompanding (NDC) [17], [18] as well as the proposed companding noise cancellation (CNC) operations are all considered in the simulations. Figure 3 shows the BER performance of OFDM system with QPSK modulation employing EC and equipped with different operations at the receiver over AWGN channel.…”

“…It has been pointed in [17] that the BER performance of companded multicarrier systems can be improved by carefully design the companding function ζ(·) [13]- [20], however, due to the amplified channel noise (by decompanding operation) or unprocessed companding noise (by no decompanding operation), this modification may be limited in practice. Hence, there is considered to be a trade-off between PAPR reduction and BER performance for companding transform.…”

“…Such as the iterative clipping and filtering [4], [5], [6], coding [7], Partial Transmission Sequence (PTS) [8], [9], [10], Selective Mapping (SLM) [11], Tone Reservation (TR) [12], companding transform (CT) [13]- [20] and so on. Among them, the clipping and companding may be the simplest two methods, since they can be employed directly to the multicarrier systems without any restrictions on the number of subcarriers and frame format and so on.…”

A Novel Nonlinear Companding Transform for PAPR Reduction in Lattice-OFDM System

“…To reduce the PAPR, many techniques have been proposed [5], such as clipping and filtering [6], coding [7], partial transmit (PTS) [8], selective mapping (SLM) [9], tone reservation [10] and companding transform [11][12][13][14][15][16][17][18][19][20]. Intuitively, the clipping and companding for OFDM system can be adopted to LOFDM system directly since they can be used without any restrictions on the system parameters [17].…”

“…Earlier nonlinear companding methods mainly focused on designing the nonlinear transfer curves directly [12,13]. Later, the work of [14] further indicated the importance of making full use of the statistical characteristics of original signals, then, many similar methods have been proposed, such as exponential companding (EC) in [15], piecewise companding (PC) in [11], [16] and [17], trapezium or trapezoidal companding (TC) in [17] and [18] as well as the simple nonlinear companding in [20], etc. It shows that the improvement of their performance is always along with the increase of the pieces of segments in their desired probability distribution function (PDF) 1 .…”