Physical layer performance enhancement for femtocell SISO/MISO soft real-time wireless communication systems employing Serial Concatenation of Quadratic Interleaved Codes

Serial Concatenation of Interleaved Codes (SCICs) is emerging as a promising technology to improve the physical layer (PHY) performance of modern wireless communication systems in terms of bit-error rate (BER), mainly due to their outstanding coding gains and feasible decoding complexities. For their channel coding performance, an interleaver is a critical component since the Minimum Hamming Distance (MHD) between legitimated permutations of the encoded bit sequence is directly influenced by the interleaver design. In this treatise, the construction of permutation mapping for SCICs is considered based on quadratic congruence, and the results are compared with the system using matrix-based block interleavers where the randomization is performed by storing and looking up elements in a matrix configuration. The performance evaluations are carried out in terms of BER for Single-Input Single-Output (SISO) and Multiple Input Single-Output (MISO) wireless communication systems in a femtocell propagation environment. The results reveal that employing quadratic interleavers yield lower BERs at both waterfall and error-floor regions, compared with the block interleavers.