Bell Laboratories Research Articles

Past Forward

Presents a photograph of John Bardeen's music box. Working at Bell Laboratories in 1949, Bardeen built three music boxes that could electronically produce five distinct notes.

:Sound Writing: Experimental Modernism and the Poetics of Articulation

:<i>Sound Writing: Experimental Modernism and the Poetics of Articulation</i>

A Probabilistic Algorithm for Computation of Polynomial Greatest Common with Smaller Factors

In the earlier work, Knuth present an algorithm to decrease the coefficient growth in the Euclidean algorithm of polynomials called subresultant algorithm. However, the output polynomials may have a small factor which can be removed. Then later, Brown of Bell Telephone Laboratories showed the subresultant in another way by adding a variant called 𝜏 and gave a way to compute the variant. Nevertheless, the way failed to determine every𝜏 correctly. In this paper, we will give a probabilistic algorithm to determine the variant 𝜏 correctly in most cases by adding a few steps instead of computing 𝑡(𝑥) when given 𝑓(𝑥) and𝑔(𝑥) ∈ ℤ[𝑥], where 𝑡(𝑥) satisfies that 𝑠(𝑥)𝑓(𝑥) + 𝑡(𝑥)𝑔(𝑥) = 𝑟(𝑥), here 𝑡(𝑥), 𝑠(𝑥) ∈ ℤ[𝑥]

Nanosys CEO Jason Hartlove's Quest for Quantum Dot Supremacy

Nanosys CEO Jason Hartlove's Quest for Quantum Dot Supremacy

The Black Scientific Renaissance of the 1970s–90s: The Legacy of African American Scientists at Bell Laboratories

The Black Scientific Renaissance of the 1970s–90s: The Legacy of African American Scientists at Bell Laboratories

Transmission Mysteries: Art and Technophilia

Transmission Mysteries: Art and Technophilia

MIMO Hybrid Satellite-Terrestrial Cooperative Systems With Spatial Modulation

With the advent of the space industry, hybrid satellite-terrestrial cooperative systems (HSTCSs) have drawn significant attention due to their prominent advantages. Besides, a novel modulation technique called spatial modulation (SM), which uses transmit antenna indices as additional information conveying source, is another technology envisioned to be used for next-generation communication systems. In this article, we propose to use SM in an HSTCS scheme consisting of a satellite, multiple terrestrial relays with multiple-input and multiple-output configuration, and a destination node equipped with multiple antennas on the ground. We derive a union bound for the symbol error probability in a fairly exact form and diversity order to shed light on the significant system parameters on the performance. Our theoretical results are validated through Monte Carlo simulations, and it is shown that using the SM technique provides a better error performance in the considered HSTCS system when compared to vertical Bell Laboratories layered space-time and space-time Alamouti codes.

Audio Signal Processing

Abstract: Audio Signal Processing is also known as Digital Analog Conversion (DAC). Sound waves are the most common example of longitudinal waves. The speed of sound waves is a particular medium depends on the properties of that temperature and the medium. Sound waves travel through air when the air elements vibrate to produce changes in pressure and density along the direction of the wave’s motion. It transforms the Analog Signal into Digital Signals, and then converted Digital Signals is sent to the Devices. Which can be used in Various things., Such as audio signal, RADAR, speed processing, voice recognition, entertainment industry, and to find defected in machines using audio signals or frequencies. The signals pay important role in our day-to-day communication, perception of environment, and entertainment. A joint time-frequency (TF) approach would be better choice to effectively process this signal. The theory of signal processing and its application to audio was largely developed at Bell Labs in the mid-20th century. Claude Shannon and Harry Nyquist’s early work on communication theory and pulse-code modulation (PCM) laid the foundations for the field.

Black scientists at Bell Labs

Black scientists at Bell Labs

Data, Science, and Global Disasters

The spread and impact of COVID-19 have disrupted human activities and energized a response of scientific activity on a remarkable, nearly unprecedented scale. This has somewhat distracted attention from a broad range of less immediate but fundamentally more serious global threats resulting from human actions. These can be collectively labelled the anthropocene disasters. Science cannot itself prevent or mitigate them. To do so requires a global policy resolve not currently existing. When and if that resolve emerges, science will be essential for guiding action. This science will be radically data-intensive, global and inclusive. Teams will be required that include the best and most motivated individuals from all relevant scientific disciplines, plus members knowledgable about implementing likely policy recommendations. Such participants must be attracted to join and then properly supported and rewarded–not likely with current academic structures. Some insights can be gained from the recent experience with COVID-19 and the much less recent example of research at Bell Labs.

We Need Something Like “Bell Labs” for the Games Industry

A long time ago, Bell Laboratories was the dream research position for many a computer scientist—new technologies were invented daily, with some of them even turning into products. Currently, the games industry has no real research organization developing the next generation technology for building games. In this article, we discuss how we should create such a research entity and some of the topics to research that come immediately to mind.

The Achievable Rate Analysis of Generalized Quadrature Spatial Modulation and a Pair of Low-Complexity Detectors

Generalized quadrature spatial modulation (GQSM) seamlessly amalgamates the generalized spatial modulation (GSM), quadrature spatial modulation (QSM) and vertical Bell Laboratories layered space-time (V-BLAST) techniques. In contrast to traditional multiple-input multiple-output (MIMO) schemes transmitting information bits only through the constellation defined on the complex plane, GQSM transmits additional information bits implicitly by selecting the transmit antenna (TA) activation pattern. The philosophy of QSM is that of separating the indices of the real and the imaginary parts of the transmit symbols, which increases the attainable throughput. In this paper, we analyze the inherent benefits of GQSM in terms of throughput. More specifically, we first derive the achievable rate expression of the recent GQSM scheme and unveil the condition for GQSM to approach the maximum rate. Furthermore, we compare the rate of the GQSM scheme to that of other transmission schemes and reveal the conditions for the GQSM&#x2019;s maximum throughput to exceed that of the benchmark schemes. Simulation results show that when the number of TAs is 40 and quadrature phase shift keying (QPSK) is adopted, the rate of the GQSM scheme may reach 150&#x0025; of that of V-BLAST. Additionally, a pair of low-complexity detectors are conceived-one based on ordered successive interference cancellation (OSIC) and another one on the orthogonal matching pursuit (OMP) algorithm.

Performance Evaluation of VBLAST and Linear Receivers for mmWave MIMO Systems with Ray-Tracing Channel Models

In this paper, the performance of a millimeter wave (mmWave) Multi-Input Multi-Output (MIMO) system is investigated using low complexity receivers. The receivers include linear Maximum Ratio Combiner (MRC), linear Zero Forcing (ZF) receiver, or linear Minimum Mean-Square Error (MMSE) receiver, in addition to ZF Vertical Bell Laboratories Layered Space-Time (ZF-VBLAST). A MIMO channel model based on a ray-tracing approach and the uniform theory of diffraction has been used. The effect of increasing the number of rays used in the channel model is investigated on the performance of all receivers. For all the scenarios, it has been found out that the ZF-VBLAST structure provides the best symbol-error-rate performance followed by the linear MMSE, then the ZF receiver, and finally the MRC receiver. The trade-off paid for achieving better performance is the increased receiver complexity. The system’s performance is compared under a conventional statistical channel model and a ray-based channel model for a fifth-generation (5G) mobile radio system. It is noted that these models do not accurately characterize the specific environment, hence resulting in an optimistic estimate of the system performance. Finally, the ray-tracing channel model is modified to account for the impact of the presence of trees within the environment. The results show that the performance degradation due to the presence of trees is between 2 to 5 dB for ZF and MMSE receivers, respectively.

On “Structural implications of the analysis of electron paramagnetic resonance spectra of natural and artificial copper proteins” by J. Peisach and W.E. Blumberg

The title article serves as a lasting product of the 25-year scientific collaboration between Jack Peisach, a biophysical chemist at the Albert Einstein College of Medicine, and William E. Blumberg, a physicist at Bell Telephone Laboratories.

Author Correction: Bringing back the golden days of Bell Labs

Author Correction: Bringing back the golden days of Bell Labs

A Forgivable Enthusiasm

A Forgivable Enthusiasm

Bringing back the golden days of Bell Labs.

Established almost 100 years ago, Bell Labs made a great contribution to advancing both fundamental science and technology. Was that the result of a unique set of circumstances or is there a reproducible recipe for success?

The First Time the Laser Was Classified

An argument between Bell Labs and ARPA in 1959 led to classification of a million-dollar ARPA project to make the first laser—and delayed the laser efforts of both parties.

BLAST PERFORMANCE IN MIMO WIRELESS COMMUNICATION SYSTEMS

Recently, a new detection algorithm for the Vertical Bell Laboratories Layered Space Time (V-BLAST) system, which we call Enhanced-V-BLAST, or simply E-V-BLAST, was proposed. V-BLAST has demonstrated very high spectral efficiency, there is a wide gap between the original V-BLAST algorithm and the Maximum Likelihood (ML) algorithm. Recently, some algorithms have been presented to make narrower this gap. In a new detection algorithm (Enhanced (E) V BLAST) for V-BLAST system was presented which showed significantly better performance and flexibility than the original V-BLAST detection. The E-V-BLAST algorithm gets closer to the optimum detection Maximum Likelihood (ML) algorithm by making decisions based on multiple symbols. The Enhanced (E)-V-BLAST has two parameters which can be adjusted to achieve a desired performance and complexity trade-off. In the present paper, we analyze the performance of EV-BLAST as a function of the two inherent adjustable parameters of E-V-BLAST. On the basis of this analysis, we obtain some useful characteristics of the E-V-BLAST algorithm which allow one to achieve the desired performance and complexity trade-off.

Ultra-Compact Microscale Heat Exchanger for Advanced Thermal Management in Data Centers

Abstract This study is focused on the experimental characterization of two-phase heat transfer performance and pressure drops within an ultracompact heat exchanger (UCHE) suitable for electronics cooling applications. In this specific work, the UCHE prototype is anticipated to be a critical component for realizing a new passive two-phase cooling technology for high-power server racks, as it is more compact and lighter weight than conventional heat exchangers. This technology makes use of a novel combination of thermosyphon loops, at the server-level and rack-level, to passively cool an entire rack. In the proposed two-phase cooling technology, a smaller form factor UCHE is used to transfer heat from the server-level thermosyphon cooling loop to the rack-level thermosyphon cooling loop, while a larger form factor UCHE is used to reject the total heat from the server rack into the facility-level cooling loop. The UCHE is composed of a double-side-copper finned plate enclosed in a stainless steel enclosure. The geometry of the fins and channels on both sides are optimized to enhance the heat transfer performance and flow stability while minimizing the pressure drops. These features make the UCHE the ideal component for thermosyphon cooling systems, where low pressure drops are required to achieve high passive flow circulation rates and thus achieve high critical heat flux values. The UCHE's thermal-hydraulic performance is first evaluated in a pump-driven system at the former laboratory of heat and mass transfer (LTCM)-Swiss Federal Institute of Technology of Lausanne, where experiments include many configurations and operating conditions. Then, the UCHE is installed and tested as the condenser of a thermosyphon loop that rejects heat to a pumped refrigerant system at Nokia Bell Labs, in which both sides operate with refrigerants in phase change (condensation-to-boiling). Experimental results demonstrate high thermal performance with a maximum heat dissipation density of 5455 (kW/m3/K), which is significantly larger than conventional air-cooled heat exchangers and liquid-cooled small pressing depth brazed plate heat exchangers. Finally, a thermal performance analysis is presented that provides guidelines in terms of heat density dissipations at the server- and rack-level when using passive two-phase cooling.