Turbo Receiver Design for Differentially Encoded PSK in Bursty Impulsive Noise Channels

Abstract

It has been recognized that the impulsive noise (IN) generated by power devices poses significant challenges to wireless receivers. In this paper, we comprehensively assess the achievable information rate (AIR) for the well-established Markov-Middleton IN model with a phase-shift keying (PSK) input sequence across various channel conditions, including matched and mismatched decoding scenarios. Upon determining information-theoretic bounds, we propose an optimal turbo-differentially encoded (DE)-PSK-IN receiver design based on a commonly used commercial transmission setup consisting of a convolutional encoder, bit-level interleaver, and a DE-PSK symbol mapper. We show that by incorporating the differential decoder into the maximum a-posteriori-based (MAP) IN detector, we can significantly enhance the receiver performance with a 4.5 dB gain compared to the conventional MAP-based turbo-PSK-IN receiver and a gap of around 1 dB to the theoretical bounds. We also propose a suboptimal separate receiver design that can be implemented with half the complexity of the joint design and near-optimal performance. We have evaluated the performance of the proposed receiver designs through extensive simulations, demonstrating their effectiveness in real-world scenarios with limited interleaver depth and mismatched state implementation.

Figures (12)

• Figure 1: Structure of a hidden Markov model, showing the factorization and conditional independencies implied by the model.
• Figure 2: Noise realization from a $4$-state Markov--Middleton impulsive noise model with a background noise variance $\sigma_0^2=1$ for impulsive index $A=0.1$ and $A=0.3$, impulsive-to-background noise power ratio $\Lambda=10$ and $\Lambda=50$, and correlation parameters $r=0$ and $r=0.9$. The orange vertical bar denotes the index $j$ of the state realizations $w_t = j$ for generating the corresponding noise samples.
• Figure 3: Trellis sections of an impulsive noise detector with a 2-state Markov--Middleton model for (a) QPSK and (b) DE-QPSK transmissions, respectively. For clarity, we only show the state transitions from states 0, 2, 4, and 6.
• Figure 4: Block diagram of a convolutional-coded bit-interleaved DE-PSK transmission over an impulsive noise channel
• Figure 5: Block diagrams of (a) optimal joint and (b) the suboptimal separate turbo-DE-PSK-IN receiver designs.