Coding Split and Adjustment to Defend OFDM-IM Against Jamming Attacks

Jamming is a simple but efficient attack method that challenges communications while traditional physical-layer defence solutions are limited. Recently, index modulation (IM) is proposed to enable index transmission in addition to data symbol transmission, which gains resistance against jamming but with limited efficacy. This letter proposes a coding split and adjustment (CSA) framework for low-density parity-check (LDPC) coding assisted orthogonal frequency division multiplexing with IM (OFDM-IM) to enhance its anti-jamming capability. CSA splits the traditionally single system code rate into an index code rate and a data code rate, each independently adjusted based on jamming impacts to error performance. Simulation results verify that OFDM-IM with CSA exhibits superior error performance over traditional OFDM-IM and OFDM in three investigated jamming scenarios. Moreover, this letter reveals that the CSA assisted OFDM-IM can still recover signals while OFDM-IM and OFDM completely fail under high jamming power.