Frequencies from 100 GHz to 3 THz are promising bands for the next generation of wireless communication systems because of the wide swaths of unused and unexplored spectrum. These frequencies also offer the potential for revolutionary applications that will be made possible by new thinking, and advances in devices, circuits, software, signal processing, and systems. This paper describes many of the technical challenges and opportunities for wireless communication and sensing applications above 100 GHz, and presents a number of promising discoveries, novel approaches, and recent results that will aid in the development and implementation of the sixth generation (6G) of wireless networks, and beyond. This paper shows recent regulatory and standard body rulings that are anticipating wireless products and services above 100 GHz and illustrates the viability of wireless cognition, hyper-accurate position location, sensing, and imaging. This paper also presents approaches and results that show how long distance mobile communications will be supported to above 800 GHz since the antenna gains are able to overcome air-induced attenuation, and present methods that reduce the computational complexity and simplify the signal processing used in adaptive antenna arrays, by exploiting the Special Theory of Relativity to create a cone of silence in over-sampled antenna arrays that improve performance for digital phased array antennas. Also, new results that give insights into power efficient beam steering algorithms, and new propagation and partition loss models above 100 GHz are given, and promising imaging, array processing, and position location results are presented. The implementation of spatial consistency at THz frequencies, an important component of channel modeling that considers minute changes and correlations over space, is also discussed. This paper offers the first in-depth look at the vast applications of THz wireless products and applications and provides approaches for how to reduce power and increase performance across several problem domains, giving early evidence that THz techniques are compelling and available for future wireless communications.

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Wireless Communications and Applications Above 100 GHz: Opportunities and Challenges for 6G and Beyond

Fast Algorithms for Signal Processing: Bibliography

—The ever increasing technological demand for the N -point transformation to an N 2 -point transformation. Such scaling can be successively applied leading to N 2 n -pointtransformations.Wehavefullypresentedthe 32 4 -point DFT approximation which stems from a multiplierless 32-point DFT approximation. The proposed approximation is equipped with a fast algorithm; we also supply the arithmetic complexity assessment and an error analysis.

Radix-$N$ Algorithm for Computing $N^{2^{n}}$-Point DFT Approximations

The two-dimensional (2-D) discrete Fourier transform (DFT) is widely used in digital signal processing (DSP) and computing applications. Fast Fourier transforms (FFTs) are widely used as low-complexity algorithms for the computation of the DFT as it reduces the required computation operations from O(N2) to O(N log 2 N). The multiplicative complexity is used as a benchmark in comparing different algorithms as it affects the circuit complexity, chip area and power. This paper introduces a new class of multiplierless hardware algorithm consisting only of arithmetic adder circuits that closely approximates the 2-D version of the 8-point DFT. The paper discusses the theory behind the proposed new algorithm, with the DFT presented in the form of an 8 × 8 matrix. Furthermore it provide a multi-beam RF aperture application example where the 2-D DFT approximation has been used to closely obtain the antenna array patterns.

Chamicth Wijenayake

Papers

Multi-beam 8×8 RF aperture digital beamformers using multiplierless 2-D FFT approximations