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In this article, architectures for interplanetary communications that feature the use of a data relay are investigated. In the considered Manuscript

In next generation Internet-of-Things, the overhead introduced by grant-based multiple access protocols may engulf the access network as a consequence of the unprecedented number of connected devices. Grant-free access protocols are therefore gaining an increasing interest to support massive access from machine-type devices with intermittent activity. In this paper, coded random access (CRA) with massive multiple input multiple output (MIMO) is investigated as a solution to design highly-scalable massive multiple access protocols, taking into account stringent requirements on latency and reliability. With a focus on signal processing aspects at the physical layer and their impact on the overall system performance, critical issues of successive interference cancellation (SIC) over fading channels are first analyzed. Then, SIC algorithms and a scheduler are proposed that can overcome some of the limitations of the current access protocols. The effectiveness of the proposed processing algorithms is validated by Monte Carlo simulation, for different CRA protocols and by comparisons with developed benchmarks.

In computer system buses, most of the energy is spent to change the voltage of each line from high to low or vice versa. Bus encoding schemes aim to improve energy efficiency by reducing the average number of transitions between successive uses of the bus. We derive in closed form the performance of optimal and suboptimal low-weight line codes designed for this purpose, and propose new algorithms for their implementation. We then show that some low-complexity suboptimal schemes have a small performance loss with respect to the optimal ones. For example, by adding 8 lines to a 128 lines bus, we save 20.7% of energy with the optimal scheme and 19.4% with suitable suboptimal schemes.

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