FEC decoders for future wireless devices: Scalability issues and multi-standard capabilities (Chapter 12)

During the last decade we have witnessed a proliferation of transmission standards for wireless communication. This holds for cellular communication, but also for broadcast and connectivity standards. All these transmission standards employ an FEC coding scheme: by adding some redundancy and appropriate coding of a signal, high transmission quality can be achieved even over noisy channels. Here transmission quality is typically measured in terms of error rates per bit or per packet. For many of these standards there also has been a rapid succession of different generations, typically driven by a quest for ever higher bit rates, a more efficient spectrum utilization, and features. These improved spectrum utilization and dramatically higher bit rates have led to an explosion in required GOPS (Giga Operations per Second), adequately supported by Moore's Law (see Fig. 12.1). As a result, the overall silicon footprint of a state-of-the-art FEC decoder for consumer products measured in square millimeter remained more or less constant over time: from 1 mm2 for a simple decoder up to 10 mm2 for demanding standards. Fortunately, FEC codes most relevant for wireless communication standards are based on a few code families only: Reed-Solomon, convolution codes (including Turbo codes), and low-density parity codes (LDPC). Some standards apply multiple codes, either in a cascaded/concatenated manner or by specifying a particular code family for different logical channels.