Forward error correction in 5G heterogeneous network

In this research, the feasibility of developing a complete polar FEC chain of 5th generation cellular mobile communication standard in software. Specifically, on general purpose processors. Paper work attempts to achieve stringent latency requirements through software, algorithmic and platform specific optimizations. Many algorithms in FEC chain are optimized for hardware implementations. Direct implementation of these algorithms in software results in poor performance. To obtain best performance in terms of latency on general purpose processors, these algorithms are modified or reformulated to suit processor architecture and software implementation. Initially both encoding and decoding FEC chains are implemented naively without any optimization. Code profiling is performed on this naive implementation to identify the significant latency contributors. The research split algorithms of significant latency contributing components into primitive operations. These primitive operations are optimized either with software optimizations or mapped to specialized functional units of a general-purpose processor to achieve best performance using CRC calculation in 5G cellular networks. Optimizations reduced the worst-case latency of the encoding FEC chain from 158µs which is more than 10x reduction in latency with communication rate

The Logic of Random Pulses: Stochastic Computing.

Recent developments in the field of electronics have produced nano-scale devices whose operation can only be described in probabilistic terms. In contrast with the conventional deterministic computing that has dominated the digital world for decades, we investigate a fundamentally different technique that is probabilistic by nature, namely, stochastic computing (SC). In SC, numbers are represented by bit-streams of 0's and 1's, in which the probability of seeing a 1 denotes the value of the number. The main benefit of SC is that complicated arithmetic computation can be performed by simple logic circuits. For example, a single (logic) AND gate performs multiplication. The dissertation begins with a comprehensive survey of SC and its applications. We highlight its main challenges, which include long computation time and low accuracy, as well as the lack of general design methods. We then address some of the more important challenges. We introduce a new SC design method, called STRAUSS, that generates efficient SC circuits for arbitrary target functions. We then address the problems arising from correlation among stochastic numbers (SNs). In particular, we show that, contrary to general belief, correlation can sometimes serve as a resource in SC design. We also show that unlike conventional circuits, SC circuits can tolerate high error rates and are hence useful in some new applications that involve nondeterministic behavior in the underlying circuitry. Finally, we show how SC's properties can be exploited in the design of an efficient vision chip that is suitable for retinal implants. In particular, we show that SC circuits can directly operate on signals with neural encoding, which eliminates the need for data conversion.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113561/1/alaghi_1.pd

The Telecommunications and Data Acquisition Report

This quarterly publication provides archival reports on developments in programs managed by JPL's Telecommunications and Mission Operations Directorate (TMOD), which now includes the former Telecommunications and Data Acquisition (TDA) Office. In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The preceding work is all performed for NASA's Office of Space Communications (OSC). TMOD also performs work funded by other NASA program offices through and with the cooperation of OSC. The first of these is the Orbital Debris Radar Program funded by the Office of Space Systems Development. It exists at Goldstone only and makes use of the planetary radar capability when the antennas are configured as science instruments making direct observations of the planets, their satellites, and asteroids of our solar system. The Office of Space Sciences funds the data reduction and science analyses of data obtained by the Goldstone Solar System Radar. The antennas at all three complexes are also configured for radio astronomy research and, as such, conduct experiments funded by the National Science Foundation in the U.S. and other agencies at the overseas complexes. These experiments are either in microwave spectroscopy or very long baseline interferometry. Finally, tasks funded under the JPL Director's Discretionary Fund and the Caltech President's Fund that involve TMOD are included. This and each succeeding issue of 'The Telecommunications and Data Acquisition Progress Report' will present material in some, but not necessarily all, of the aforementioned programs

Applications of topology to Weyl semimetals and quantum computing

This thesis covers various applications of topology in condensed matter physics and quantum information. It studies how the topology of the electronic structure of a Weyl semimetal affects the transport behaviour of electrons in an applied magnetic field, and how one may employ similar ideas in materials containing Majorana modes to speed up chemistry calculations on a quantum computer. It develops and tests new techniques for decoding topological quantum error correcting codes, in particular for detailed simulation on near-term devices. Finally, it looks towards improving quantum algorithms for future applications in quantum simulation; in particular the classical post-processing of data taken during quantum phase estimation experiments.European Research Council; Netherlands Organization for Scientific ResearchQuantum Matter and Optic