Masoud Ardakani

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We introduce a new one-dimensional (1-D) analysis of low-density parity-check (LDPC) codes on additive white Gaussian noise channels which is significantly more accurate than similar 1-D methods. Our method assumes a Gaussian distribution in message-passing decoding only for messages from variable nodes to check nodes. Compared to existing work, which makes(More)
The optimal performance-complexity tradeoff for error-correcting codes at rates strictly below the Shannon limit is a central question in coding theory. This paper proposes a numerical approach for the minimization of decoding complexity for long-block-length irregular low-density parity-check (LDPC) codes. The proposed design methodology is applicable to(More)
For the first time, the performance of pairwise amplify-and-forward multi-way relay networks (MWRNs) is studied. To this end, new end-to-end signal-to-noise ratio (e2e SNR) expression at an arbitrary source is first derived in closedform, and thereby, an insightful statistical characterization is developed. In this context, tight closed-form approximations(More)
Two new transmit/receive (Tx/Rx) antenna selection strategies are proposed and analyzed for two-way multipleinput multiple-output (MIMO) amplify-and-forward (AF) relay networks. These two strategies select the best transmit and receive antennas at the two sources and the relay based on (i) minimizing the overall outage probability and (ii) maximizing the(More)
We apply irregular low-density parity-check (LDPC) codes to the design of multilevel coded quadrature amplitude modulation (QAM) schemes for application in discrete multitone systems in frequency-selective channels. A combined Gray/Ungerboeck scheme is used to label each QAM constellation. The Gray-labeled bits are protected using an irregular LDPC code(More)
We study an asymmetric multi-way relay channel where users have different channel conditions. To enable data exchange between the users, an existing practical approach, where users transmit their data to the relay in pairs, is considered. For pairwise transmission, we consider two different scenarios at the relay, called functional-decode-forward (FDF) and(More)
This paper considers a class of iterative messagepassing decoders for low-density parity-check codes in which the decoder can choose its decoding rule from a set of decoding algorithms at each iteration. Each available decoding algorithm may have a different per-iteration computation time and performance. With an appropriate choice of algorithm at each(More)
Four joint relay and antenna selection strategies for dual-hop amplify-and-forward (AF) multiple-input multipleoutput relay networks are studied. Two of them require full channel state information (CSI) whereas the other two require only partial CSI. The relays are either channel-assisted AF or fixed-gain AF type. The first joint selection strategy involves(More)