The recent evolution of mobile communication systems toward a 5G network is associated with the search for new types of non-orthogonal modulations such as sparse code multiple access (SCMA). Such modulations are proposed in response to demands for increasing the number of connected users. SCMA is a non-orthogonal multiple access technique that offers improved bit error rate performance and higher spectral efficiency than other comparable techniques, but these improvements come at the cost of complex decoders. There are many challenges in designing near-optimum high throughput SCMA decoders. This paper explores means to enhance the performance of SCMA decoders. To achieve this goal, various improvements to the MPA algorithms are proposed. They notably aim at adapting SCMA decoding to the single instruction multiple data paradigm. Approximate modeling of noise is performed to reduce the complexity of floating-point calculations. The effects of forwarding error corrections such as polar, turbo, and LDPC codes, as well as different ways of accessing memory and improving power efficiency of modified MPAs are investigated. The results show that the throughput of an SCMA decoder can be increased by 3.1 to 21 times when compared to the original MPA on different computing platforms using the suggested improvements. INDEX TERMS 5G, BER, exponential estimations, intel advanced vector extensions (AVX), iterative multiuser detection, knights corner instruction (KNCI), log-MPA, maximum likelihood (ML), message passing algorithm (MPA), power efficiency, SCMA, single instruction multiple data (SIMD), streaming SIMD extension (SSE).

Convolutional Neural Networks (CNNs) have a major impact on our society, because of the numerous services they provide. These services include, but are not limited to image classification, video analysis, and speech recognition. Recently, the number of researches that utilize FPGAs to implement CNNs are increasing rapidly. This is due to the lower power consumption and easy reconfigurability that are offered by these platforms. Because of the research efforts put into topics, such as architecture, synthesis, and optimization, some new challenges are arising for integrating suitable hardware solutions to high-level machine learning software libraries. This paper introduces an integrated framework (CNN2Gate), which supports compilation of a CNN model for an FPGA target. CNN2Gate is capable of parsing CNN models from several popular high-level machine learning libraries, such as Keras, Pytorch, Caffe2, etc. CNN2Gate extracts computation flow of layers, in addition to weights and biases, and applies a “given” fixed-point quantization. Furthermore, it writes this information in the proper format for the FPGA vendor’s OpenCL synthesis tools that are then used to build and run the project on FPGA. CNN2Gate performs design-space exploration and fits the design on different FPGAs with limited logic resources automatically. This paper reports results of automatic synthesis and design-space exploration of AlexNet and VGG-16 on various Intel FPGA platforms.

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Nowadays, many industries are in favor of using intelligent design-space exploration as opposed to brute-force analysis. In many applications, the design-space is defined by multiple variables and their interactions. Although brute-force analysis is very simple, it is rarely scalable when the number of variables in the system increases. With the rising complexity of hardware designs, more intelligent approaches are needed to explore the design options. This paper proposes using smart meta-heuristic search algorithms such as Grey Wolf Optimization (GWO) in conjunction with Bayesian Optimization (BO) to solve this problem. We show that we can further reduce the design effort using a surrogate model that is created based on a novel hybrid GWO-BO method. The surrogate model is a useful abstraction to detect functional and physical inter-dependencies in the system in order to accurately predict its performance (e.g. throughput or latency). We evaluate our methodology and show that it can produce competitive results in order to find the best design variables that maximize performance of the system. Finally, we compare our results with previous statistical and heuristic methods proposed in the literature and find that the proposed GWO-BO method always performs better than the other considered methods.