On the Performance of a Multi-Edge Type LDPC Code for Coded Modulation

We present an error-correcting code which merges error-correction and modulation. The code is an extension of a Low-Density Parity-Check (LDPC) code, and can be viewed as a multi-edge type LDPC code. The symbols of the codewords are from a ternary alphabet, and have a different probability of occurrence. When the code is used on the complex Additive White Gaussian Noise (AWGN) channel, the spectral efficiency is 2 bit/s/Hz. Therefore, the code is suitable for bandwidth-efficient communication. Simulations on the AWGN channel show that the code outperforms several other coded modulation schemes proposed in literature

Error Probability Bounds for Gaussian Channels under Maximal and Average Power Constraints

This paper studies the performance of block coding on an additive white Gaussian noise channel under different power limitations at the transmitter. Lower bounds are presented for the minimum error probability of codes satisfying maximal and average power constraints. These bounds are tighter than previous results in the finite blocklength regime, and yield a better understanding on the structure of good codes under an average power limitation. Evaluation of these bounds for short and moderate blocklengths is also discussed.Comment: Submitted to the IEEE Transactions on Information Theory. This article was presented in part at the 2019 IEEE International Symposium on Information Theory, Paris, France (ISIT 2019) and at the 2020 International Z\"urich Seminar on Communication and Information, Z\"urich, Switzerland (IZS 2020

The Trade-off between Processing Gains of an Impulse Radio UWB System in the Presence of Timing Jitter

In time hopping impulse radio, $N_f$ pulses of duration $T_c$ are transmitted for each information symbol. This gives rise to two types of processing gain: (i) pulse combining gain, which is a factor $N_f$, and (ii) pulse spreading gain, which is $N_c=T_f/T_c$, where $T_f$ is the mean interval between two subsequent pulses. This paper investigates the trade-off between these two types of processing gain in the presence of timing jitter. First, an additive white Gaussian noise (AWGN) channel is considered and approximate closed form expressions for bit error probability are derived for impulse radio systems with and without pulse-based polarity randomization. Both symbol-synchronous and chip-synchronous scenarios are considered. The effects of multiple-access interference and timing jitter on the selection of optimal system parameters are explained through theoretical analysis. Finally, a multipath scenario is considered and the trade-off between processing gains of a synchronous impulse radio system with pulse-based polarity randomization is analyzed. The effects of the timing jitter, multiple-access interference and inter-frame interference are investigated. Simulation studies support the theoretical results.Comment: To appear in the IEEE Transactions on Communication