Index Modulation OFDM Systems with Direct Pattern of Subcarrier Activation

Abstract

OFDM-IM is a spatial modulation technique applied to OFDM's block subcarriers, resulting in a modified version of OFDM. Compared to traditional OFDM, OFDM-IM boasts several benefits, such as enhanced bit-error rate (BER) performance and power efficiency. When working with OFDM-IM, the specification of subcarrier-activation-patterns (SAPs) is done by utilizing either look-up tables (LUTs) or a combinatorial approach to conform with data. However, the data-to-SAP mapping methods of both suffer from increased complexity as the number of subcarriers expands. The paper proposes a direct data-to-SAP mapping that eliminates the need for any type of look-up tables. Through the presented analysis and computer simulation results, it is demonstrated that the OFDM-IM system utilizing the proposed mapping scheme outperforms equivalent traditional OFDM-IM systems in both complexity and bit error rate (BER) performance.