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..

Downlink MIMO in LTE-advanced: SU-MIMO vs. MU-MIMO

Abstract: Single-user multi-antenna technologies are well upported in current standard specifications like LTE Release 8/9. Further development of the specification (LTE-Advanced) is expected to conform to the requirements for IMT-Advanced systems. One of the key enabling features of LTE-Advanced to meet IMT-Advanced downlink performance requirements is multi-user MIMO, where a transmitter serves multiple users simultaneously on the same frequency resource, primarily relying on spatial separation. In general, multi-user MIMO is beneficial for improving average user spectral efficiency. However, cell edge user spectral efficiency may be reduced if multi-user MIMO is used exclusively, due to residual inter-user interference arising from practical multi-user beamforming and reduced transmit power allocated to each user. Therefore, it should be possible to configure the UE-specific transmission mode to support dynamic switching between single-user MIMO and multi-user MIMO to balance the cell edge user spectral efficiency as well as the average cell user spectral efficiency. In this article, we study various aspects of multi-user MIMO including design philosophy, multi-user precoding, and control signaling. The associated feedback schemes, including those that facilitate dynamic switching, are discussed. Performance evaluation is conducted to demonstrate the gain of dynamically switched single-user and multiuser MIMO as opposed to traditional single-user MIMO.

Adaptive power control for wireless charging

Abstract: Exemplary embodiments are directed to wireless power transfer. A transmitter (202) generates an electromagnetic field at a resonant frequency with a transmit antenna to create a coupling -mode region within a near field of the transmit antenna (204). The transmitter defines a beginning of a recurring period by on-off keying the electromagnetic field during a synchronization portion of the recurring period. During a power transmission portion of the recurring period, the transmitter couples portions of the electromagnetic field to different receive antennas of various receiver devices within the coupling -mode region. The transmitter also determines a power allocation within the recurring period for the various receiver devices disposed within the coupling -mode region and adjusts a power level of the near field radiation responsive to power requirements received from the receiver devices.

High speed media access control with legacy system interoperability

Abstract: Techniques for MAC processing for efficient use of high throughput systems that is backward compatible with various types of legacy systems are disclosed. In one aspect a first signal is transmitted according to a legacy transmission format to reserve a portion of a shared medium, and communication according to a second transmission format transpires during the reserved portion. In another aspect, a communication device may contend for access on a legacy system, and then communicate according to a new class communication protocol with one or more remote communication devices during the access period. In another aspect, a device may request access to a shared medium according to a legacy protocol, and, upon grant of access, the device may communicate with or facilitate communication between one or more remote stations according to a new protocol.

Modified preamble structure for ieee 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, mimo or otherwise extended devices

Abstract: A modified preamble is used by extended devices that operate at higher rates, MIMO or other extensions relative to strict 802.11a-compliant devices. The extended devices might use multiple antenna techniques (MIMO), where multiple data streams are multiplexed spatially and/or multi-channel techniques, where an extended transmitter transmits using more than one 802.11a channel at a time. Such extensions to IEEE 802.11a can exist in extended devices. The modified preamble is usable for signaling, to legacy devices as well as extended devices, to indicate capabilities and to cause legacy devices or extended devices to defer to other devices such that the common communication channel is not subject to unnecessary interference. The modified preamble is also usable for obtaining MIMO channel estimates and/or multi-channel estimates. The modified preamble preferably includes properties that facilitate detection of conventional and/or extended modes (“mode detection”) and provides some level of coexistence with legacy IEEE 802.11a devices.

Multi-panel device with configurable interface

Abstract: A multi-panel device is disclosed. In a particular embodiment, the device includes a first hinge coupled to a first panel and coupled to a second panel. The first panel includes a first display surface and the second panel includes a second display surface. The second hinge is coupled to the second panel and coupled to a third panel that includes a third display surface. The device also includes a sensor coupled to the first hinge to detect a relative orientation of the first panel to the second panel. The device includes a processor responsive to the sensor to detect a device configuration. The processor is configured to adjust a user interface displayed at the first display surface, the second display surface, and the third display surface based on the detected device configuration.