An OFDM Spectrum Suppressed Transmission Using FEC Metric Masking for LDPC Coding

An OFDM (Orthogonal Frequency Division Multiplexing) spectrum suppressed transmission is one of the most effective schemes to increase frequency utilization efficiency for wireless communications. It makes the required bandwidth of the transmitted signal narrower than the Nyquist bandwidth, while maintaining the throughput as much as possible. It has the advantage of being easy to implement in hardware by replacing some subcarriers with null subcarriers for the spectrum suppression based on OFDM modulation. Until now, the frequency utilization efficiency of OFDM spectrum suppressed transmission has previously been evaluated only for a conventional FEC (Forward Error Correction) of convolutional coding and Viterbi decoding. Moreover, FEC metric masking, which replaces the metric values of the null subcarriers with the neutral values at the receiver, has also been proposed to improve the degraded transmission quality due to the spectrum suppression.This paper proposes an OFDM spectrum suppressed transmission using FEC metric masking for a more powerful FEC of LDPC (Low Density Parity Check) coding. The quantitative evaluation clarifies that the proposed scheme can achieve better frequency utilization efficiency compared to that without FEC metric masking.