Design of Anti-Eavesdropping Scheme for SLT-LT Codes Based on Random Symbol Sets

In recent years, physical layer security technology has provided a new way to solve the problem of secure transmissions in wireless communications from an information theory perspective by using physical layer security coding and the inherent characteristics of the channel. As a nonsystematic code, Luby transform (LT) code has the characteristics of random coding and rateless, therefore, eavesdroppers cannot directly obtain useful information from leaked code symbols. As a shifted LT (SLT) code, the SLT codes can efficiently recover information, with a smaller decoding overhead. Therefore, we propose an SLT-LT joint code anti-eavesdropping scheme based on random symbol sets. Based on the environment of the main channel, the sender selects a set of random symbols to send to legitimate receivers as known symbols and uses these random symbols and message symbols to form source symbols for the SLT-LT concatenated coding to increase the bit error rate (BER) of the eavesdroppers. The experimental results show that, compared with other anti-eavesdropping LT schemes, our proposed scheme only adds a small amount of decoding overhead but has a better security performance.