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Abstract The logarithmic number system (LNS) can be used to simplify the computation of arithmetic functions, such as multiplication. This article proposes three leading‐one detectors (LODs) to speed up the binary logarithm calculation in the LNS. The first LOD (LOD I) uses a single fixed value to approximate the d least significant bits (LSBs) in the outputs of the LOD. The second design (LOD II) partitions the d LSBs into smaller fields and uses a multiplexer to select the closest approximation to the exact value. These two LODs help with error cancellation as they introduce signed errors for inputs N < 2d. Additionally, a scaling scheme is proposed that scales up the input N < 2d to avoid large approximation errors. Finally, an improved exact LOD (LOD III) is proposed that only passes half of the input N to the LOD; the more significant half is passed if there is at least one ‘1’ in that half; otherwise, the less significant half is passed. Our simulation results show that the 32‐bit LOD III can be up to 2.8× more energy‐efficient than existing designs in the literature. The Mitchell logarithmic multiplier and a neural network are considered to further illustrate the practicality of the proposed designs.

The Deflate compression algorithm provides one of the most widely used solutions for lossless data compression. Field-programmable gate arrays (FPGAs) are commonly used to implement hardware accelerators that speed up computation-intensive applications. In this article, FPGA-based accelerators for Deflate compression and decompression are described. These accelerators were specified in C++ and synthesized using Vivado High-Level Synthesis (HLS) for a Xilinx Virtex UltraScale+ series FPGA and a system clock frequency of 250 MHz. The proposed compressor processes data at a fixed input throughput of 4.0 GB/s and achieves a geometric mean compression ratio of 1.92 on the Calgary corpus benchmark files using static Huffman encoding. While not the first compressor synthesized using high-level synthesis, our design achieves a 25% greater throughput and an 11% greater compression ratio than the only other published design that uses Vivado HLS. The proposed decompressor design achieves average input throughputs of 196.61 MB/s and 97.40 MB/s, for statically and dynamically encoded Calgary corpus files, respectively. This is the first published decompressor design that is synthesized using high-level synthesis and provides performance that is comparable to that of the best published designs, having static throughputs 11% higher and dynamic throughputs only 10% lower than the expertly-optimized design sold by Xilinx.

A channel simulator is an essential component in the development and accurate performance evaluation of wireless systems. A key technique for producing statistically accurate fading variates is to shape the flat spectrum of Gaussian variates using digital filters. This paper addresses various challenges when designing real and complex spectrum shaping filters with quantized coefficients for efficient realization of both isotropic and nonisotropic fading channels. An iterative algorithm for designing stable complex infinite impulse response (IIR) filters with fixed-point coefficients is presented. The performance of the proposed filter design algorithm is verified with 16-bit fixed-point simulations of two example fading filters.

Forward error correction (FEC) improves the quality of compressed video transmitted through a lossy network for real-time applications such as video streaming. The FEC techniques are generally applied on source video packets at the frame level. In this paper, we propose a technique where the FEC is applied on source packets at the group-of-pictures (GoP) level assuming an MPEG-like compression scheme. We derive analytically an estimate of the average playable frame rate for a given packet loss probability. Our analysis over a range of network conditions indicates that in most practical network conditions, the proposed technique provides a larger playable frame rate compared to the frame-level FEC technique. This analysis results are also validated by video streaming simulations conducted on the NS-2 network simulator. [ABSTRACT FROM AUTHOR]