Null Subcarrier Index Modulation in OFDM Systems for 6G and Beyond

Area of Science:

• Electrical Engineering
• Telecommunications
• Signal Processing

Background:

• Orthogonal Frequency Division Multiplexing (OFDM) systems face computational complexity challenges with Index Modulation (IM).
• Existing OFDM-IM techniques primarily modulate active subcarrier indices, limiting efficiency.

Purpose of the Study:

• To propose a novel Index Modulation (IM) technique for OFDM systems using null subcarrier locations (NSC-OFDM-IM).
• To reduce computational complexity in OFDM-IM systems.
• To enhance spectral efficiency and bit error rate (BER) performance.

Main Methods:

• Developed a new IM technique by utilizing null subcarrier locations within predefined subgroups.
• Implemented index selection and detection algorithms focusing on null subcarriers.
• Defined subgroup sizes as powers of two for straightforward implementation.

Main Results:

• The proposed NSC-OFDM-IM shows no performance degradation compared to existing OFDM-IM.
• Achieved improved bit error rate (BER) performance over conventional OFDM.
• Demonstrated enhanced spectral efficiency (SE) compared to conventional OFDM.
• Significantly reduced computational complexity compared to traditional OFDM-IM.

Conclusions:

• The novel NSC-OFDM-IM technique effectively addresses computational complexity in OFDM systems.
• This method offers superior BER and SE performance compared to conventional OFDM.
• The approach is practical, easy to implement, and computationally efficient.