Coded modulation (CM) refers to a system where an encoder is combined with a higher order modulator with more than one bit per symbol to increase the spectral efficiency. Examples of encoders can be simple block codes or convolutional codes, to more advanced encoders like turbo codes or low-density parity-check (LDPC) codes. Commonly used higher order modulations are pulse-amplitude modulation (PAM), quadrature-amplitude modulation (QAM), and phase-shift keying (PSK).
Early examples of CM systems are trellis-coded modulation (TCM), where a binary convolutional encoder is combined with a memoryless modulator. Nowadays, more advanced CM systems usually insert a bit interleaver between the encoder and the modulator, so called bit-interleaved coded modulation (BICM). The CM system can also be extended to multiple-input multiple-output (MIMO) systems, consisting of several antennas at the transmitter and at the receiver. Different flavors of these systems are used in many wireless standards today such as IEEE 802.11a/g/n/ac/p, 4G (HSDPA and HSUPA), 3GPP Long Term Evolution (LTE), WiMAX, and the latest DVB standards (DVB-T2, DVB-S2, and DVB-C2).
This project deals with the evaluation and optimization of CM systems. The systems will be optimized theoretically and numerically and their performance will be evaluated by analysis and simulations. The project is aimed at developing information-theoretic and performance bounds to analyze CM systems. The theoretical analysis will be used to derive optimization criteria for the design of good combinations of encoders and modulators (including the bit-to-symbol mapping).