Multi-level rate-splitting for synchronous and asynchronous interference channels

Rate-splitting, in which rates are split into smaller rates and successive decoding is used, has been developed for memoryless multiple access channels (MACs). This scheme realizes any rate in the capacity region of a MAC with decoding complexity proportional to that for single-user codes, even when time-sharing cannot be used. This paper proposes rate-splitting schemes for multiple-receiver channels, such as compound MACs and interference channels. For interference channels, rate-splitting can achieve any rate in the celebrated Han-Kobayashi rate region with low decoding complexity. Rate-splitting is particularly effective in the frame-asynchronous case, and an achievable rate region for the asynchronous IC is given.