Polynomial Cancellation Coded DFT-s-OFDM for Low-PAPR Uplink Signaling

Abstract

The physical layer signaling of the 5G new radio still utilizes cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) and discrete Fourier transform-spread-OFDM (DFT-s-OFDM) to support 5G services for the sake of system-backward compatibility. However, the transmission requirements among these services differ, and this poses a challenge to the adaptability of the waveforms with regard to the peak-to-average power ratio (PAPR) issue. In particular, DFT-s-OFDM serving as a low-PAPR option for uplink signaling still has room for PAPR improvement in cases such as machine-type and device-to-device communications. We propose polynomial cancellation coded (PCC)-DFT-s-OFDM to flexibly reduce the PAPR of conventional DFT-s-OFDM. The principle of the proposed method, including its transform, is analyzed in the time domain. The results show that it can also be regarded as a novel spectral shaping scheme for PAPR reduction. Through a parameter designed for adjusting the cost of spectral efficiency, the proposed method can regulate the extent of improvement compared with the conventional DFT-s-OFDM, not only in the PAPR, but also for the spectral radiation and bit error rate when considering the nonlinearity of the power amplifier. The increase in computational complexity is neglectable owing to the simplicity of generalized PCC, making it apt to be deployed in existing systems.

Retracted: Peak to average power ratio reduction of ZT DFT‐S‐OFDM signals using hybrid improved monarch butterfly optimization‐PTS scheme with TR‐clipping scheme

“…where C 0 initial value of peak-reduction symbol, Q is Nl  NL matrix with each element expressed as 1 ffiffiffi…”

“…Current mobile wireless standards such as IEEE 802.11, wireless local area networks (WLANs), 4G‐(LTE) deployed orthogonal frequency division multiplexing waveform as a vehicle for communication. OFDM has definitely stood itself as a dominant waveform for its use in digital video and audio broadcasting (DAB‐DVB) 1 . Nevertheless, this waveform has few prolonged implementation issues, the predominating one being the high peak‐to‐average power ratio (PAPR) 2,3 .…”

Bit‐level implementation for polynomial cancellation coded DFT‐s‐OFDM transmitters

“…Let N is the fast Fourier transform size, and M is the allocated subcarriers of certain user based on the localised frequency domain multiple access [2, 5]. The frequency‐domain data vector of PCC‐DFT‐s‐OFDM is given by where is the M ‐by‐ M DFT matrix, is the input phase‐shift keying (PSK)/quadrature amplitude modulation (QAM) symbol vector, is the transpose and is the d ‐order M ‐by‐ P PCC mapping matrix [7] whose entries are zeros except for and . Namely, the PCC mapping generates M symbols from input PSK/QAM symbols, and the conventional DFT‐s‐OFDM is thus a special case of PCC‐DFT‐s‐OFDM when is applied.…”

“…To solve this, polynomial cancellation coded (PCC)‐DFT‐s‐OFDM [7] has been recently introduced for improving the flexibility of DFT‐s‐OFDM on the tradeoff between spectral efficiency (SE) and PAPR performance for some SE‐tolerable services. Aiming to be fully compatible with current LTE/NR user equipments (UEs), however, directly implementing PCC mapping on DFT‐s‐OFDM in the symbol level still needs the alteration to UE circuits, albeit only adding a simple subtractor.…”

“…. , s P−1 [ ] T is the input phase-shift keying (PSK)/quadrature amplitude modulation (QAM) symbol vector, • [ ] T is the transpose and P is the d-order M-by-P PCC mapping matrix [7] whose entries are zeros except P(2 d m, m) = (−1) u , . .…”