Serial concatenation with simple block inner codes

When designing communication systems based on serially concatenated codes and iterative decoding, it is common practice to use recursive convolutional codes as inner codes. In this paper we show that very good performance can also be obtained by using simple block codes as inner codes. In particular, we propose a simple extension of a single parity check encoder that produces large Hamming weight output sequences for weight one input sequences. We also present a soft decoding algorithm and use a uniform interleaver analysis and EXIT charts to design efficient schemes that perform well in both the waterfall and error floor regions of the bit error rate curve