Decoding high code rate Turbo codes by their reciprocal dual trellis has been shown to be potentially beneficial in implementation due to the simpler trellis structures. However, reciprocal dual trellis decoders' complexity grows significantly when the code rate is less than 1/2. Further, designing a multi-code rate reciprocal dual trellis decoder is even more challenging if periodical puncturing patterns is not always available. In this paper, a radix-4 hybrid-trellis LTE-A turbo decoder with a controller switching between the conventional trellis and the reciprocal dual trellis is presented. To accommodate all the rates defined in LTE-A, a zero patching scheme is proposed to create the periodical puncturing patterns required by the reciprocal dual trellis decoding. The implementation of the proposed decoder supports all the code rates, from 1/3 to 0.95, and all the 188 block lengths. Fabricated in TSMC TN28HPM process, the post-layout simulations show the proposed decoder could achieve 333Mbps at 6 iterations under 263MHz operating frequency. The core area is 1.08 mm2, and the decoder draws 295.57 mW of power with energy efficiency of 0.148(nJ/bit/iter).

With shrinking process technology, decreasing supply voltage, and increasing clock frequency, noise reduction becomes more and more crucial to the success of modern mixed-signal system-on-chip design. To eliminate the switching noise due to crosstalk coupling between analog and digital signals, it is essential to fully separate the routing paths of analog and digital nets when generating mixed-signal layouts. Different from previous works which cannot fully separate analog and digital routing paths, this paper presents a novel hierarchical deterministic mixed-signal layout synthesis approach with the separation of analog and digital signal paths for switching noise elimination. Experimental results based on a third-order Σ Δ modulator show that the proposed approach can result in various layouts with separated analog and digital signal paths while achieving better signal-to-noise and distortion ratio, and overall performance specifications.