Diversity-security tradeoff for compound channels

We propose new rate-flexible low-density parity-check (LDPC) coding schemes for secrecy over a compound channel with L parallel links. These codes, called anti-root LDPC codes, have good performance at both finite and asymptotic code length while all links are jointly encoded. Firstly, an algebraic security scheme is developed based on the anti-root LDPC ensemble and a source splitter. Secondly, an information theoretic security scheme is built from the same splitter with the adjunction of a random sequence. Then, we present a new diversity-security tradeoff for channels exhibiting block fading or block erasure. Finally, we describe anti-root LDPC ensembles with higher diversity or security orders to attain the aforementioned tradeoff.