Qualcomm

About: Qualcomm is a company organization based out in Farnborough, United Kingdom. It is known for research contribution in the topics: Wireless & Signal. The organization has 19408 authors who have published 38405 publications receiving 804693 citations. The organization is also known as: Qualcomm Incorporated & Qualcomm, Inc..

Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin–orbit and spin-transfer torques

Abstract: Magnetization switching in magnetic tunnel junctions using spin-transfer torque and spin–orbit torque is key to the development of future spintronic memories. However, both switching mechanisms suffer from intrinsic limitations. In particular, the switching current in spin-transfer torque devices needs to be lowered, whereas an external magnetic field is required for spin–orbit torque devices to achieve deterministic switching in perpendicular magnetic tunnel junctions. Here, we experimentally demonstrate field-free switching of three-terminal perpendicular-anisotropy magnetic tunnel junction devices through the interaction between spin–orbit and spin-transfer torques. We show that the threshold current density of spin–orbit torque switching can be reduced by increasing the spin-transfer torque current density, and thus an optimal point for low-power perpendicular magnetic tunnel junction switching can be found by tuning the two current densities. Furthermore, and due to this interplay, low-power switching in two-terminal perpendicular magnetic tunnel junctions without an external magnetic field is also achieved. The interplay between spin–orbit and spin-transfer torques can be used to develop a low-power route to magnetization switching of perpendicular magnetic tunnel junctions without an external magnetic field.

Method and apparatus for random access in an orthogonal multiple-access communication system

Abstract: Techniques for accessing a wireless communication system are described. A user equipment (UE) sends a random access preamble for system access. The random access preamble may include a random identifier (ID), a channel quality indicator (CQI), etc. The UE may randomly select the random ID or may be assigned this random ID. The UE receives a random access response from a base station. The random access response may include control channel resources (e.g., CQI and PC resources), uplink resources, and/or control information (e.g., timing advance and PC correction) for the UE. The random access response may be sent in two parts using two messages. A first message may be sent on a control channel and may include identification information and possibly other information. A second message may be sent on a shared data channel and may include remaining information for the random access response.

5G 3GPP-Like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments

Abstract: For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not addressed by existing channel models developed for bands below 6 GHz. This document presents a preliminary overview of 5G channel models for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a multitude of frequencies from 6 GHz to 100 GHz, and this document describes an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells (UMa), and 2) a baseline model for incorporating path loss, shadow fading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies such as clustering and antenna decoupling algorithms are also presented.

Force sensing touch screen

Abstract: A computing device includes a touch screen display with a plurality of force sensors, each of which provides a signal in response to contact with the touch screen display. Using force signals from the plurality of force sensors, a characteristic of the contact is determined, such as the magnitude of the force, the centroid of force and the shear force. The characteristic of the contact is used to select a command which is processed to control the computing device. For example, the command may be related to manipulating data displayed on the touch screen display, e.g., by adjusting the scroll speed or the quantity of data selected in response to the magnitude of force, or related to an operation of an application on the computing device, such as selecting different focal ranges, producing an alarm, or adjusting the volume of a speaker in response to the magnitude of force.

Efficient parallel-stage power amplifier

Abstract: An amplifier circuit (40) for providing an amplified signal in response to an input signal. The amplifier circuit (40) includes an input network (44) for applying the input signal to a selected at least one of a plurality of amplifier stages. An output network (48) is provided for coupling the amplified signal from the selected at least one amplifier stage. The appropriate amplifier stage is selected by a control circuit (56) in response to a desired power value of the amplified signal. By selectively activating only the amplifier stage(s) that is/are necessary to provide the desired level of output power, increased DC efficiency can be accomplished in applications that require an amplifier which operates linearly over a wide dynamic range.