Green OFDM for IoT: Minimizing IBO subject to a spectral mask

Abstract

Applying orthogonal frequency division multiplexing (OFDM) for internet of things (IoT) network cause significant power consumption by power amplifiers (PAs) due to the requirement of large input back-off (IBO) values for keeping signal linearity. In this paper, different IBO values of PA with or without clipping and filtering (CF) technique for IEEE 802.11ah uplink transmission is evaluated and compared in terms of power spectral density (PSD) and bit error rate (BER). Assuming the BER degradation can be mitigated at high-quality receivers by some compensation techniques which is suitable for discontinuous transmission in IoT network, the minimum IBO could benefit the power efficiency of OFDM IoT devices where make them greener. The results show that the minimum IBO value is 3 dB which exactly matching the spectral mask for PSD. With the aid of CF, it can be improved to 0 dB while the BER performance as a trade-off is needed.