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..

cdma2000/sup /spl reg// high rate broadcast packet data air interface design

Abstract: The Third Generation Partnership Project 2 recently baselined the specification for a cdma2000/sup /spl reg// high-rate broadcast packet data air interface ("cdma2000 High Rate Broadcast-Multicast Packet Data Air Interface Specification", 3GPP2 C.50054). The standard allows high-speed delivery of packet data to multiple access terminals. The article describes the air interface design adopted by 3GPP2, and presents simulation results that predict the performance of the high-speed broadcast system.

Method and apparatus for time-aligning transmissions from multiple base stations in a CDMA communication system

Abstract: Schemes to time-align transmissions from multiple base stations to a terminal. To achieve time-alignment, differences between the arrival times of transmissions from the base stations, as observed at the terminal, are determined and provided to the system and used to adjust the timing at the base stations such that terminal-specific radio frames arrive at the terminal within a particular time window. In one scheme, a time difference between two base stations is partitioned into a frame-level time difference and a chip-level time difference. Whenever requested to perform and report time difference measurements, the terminal measures the chip-level timing for each candidate base station relative to a reference base station. Additionally, the terminal also measures the frame-level timing and includes this information in the time difference measurement only if required. Otherwise, the terminal sets the frame-level part to a predetermined value (e.g., zero).

Beamforming Tradeoffs for Initial UE Discovery in Millimeter-Wave MIMO Systems

Abstract: Millimeter-wave (mmW) multi-input multi-output (MIMO) systems have gained increasing traction toward the goal of meeting the high data-rate requirements in next-generation wireless systems. The focus of this work is on low-complexity beamforming approaches for initial user equipment (UE) discovery in such systems. Toward this goal, we first note the structure of the optimal beamformer with per-antenna gain and phase control and establish the structure of good beamformers with per-antenna phase-only control. Learning these right singular vector (RSV)-type beamforming structures in mmW systems is fraught with considerable complexities such as the need for a non-broadcast system design, the sensitivity of the beamformer approximants to small path length changes, inefficiencies due to power amplifier backoff, etc. To overcome these issues, we establish a physical interpretation between the RSV-type beamformer structures and the angles of departure/arrival (AoD/AoA) of the dominant path(s) capturing the scattering environment. This physical interpretation provides a theoretical underpinning to the emerging interest on directional beamforming approaches that are less sensitive to small path length changes. While classical approaches for direction learning such as MUltiple SIgnal Classification (MUSIC) have been well-understood, they suffer from many practical difficulties in a mmW context such as a non-broadcast system design and high computational complexity. A simpler broadcast-based solution for mmW systems is the adaptation of limited feedback-type directional codebooks for beamforming at the two ends. We establish fundamental limits for the best beam broadening codebooks and propose a construction motivated by a virtual subarray architecture that is within a couple of dB of the best tradeoff curve at all useful beam broadening factors. We finally provide the received ${\text{SNR}}$ loss-UE discovery latency tradeoff with the proposed beam broadening constructions. Our results show that users with a reasonable link margin can be quickly discovered by the proposed design with a smooth roll-off in performance as the link margin deteriorates. While these designs are poorer in performance than the RSV learning approaches or MUSIC for cell-edge users, their low-complexity that leads to a broadcast system design makes them a useful candidate for practical mmW systems.

User interface for mobile devices

Abstract: A mobile user interface suitable for mobile computing devices uses device position/orientation in real space to select a portion of content that is displayed. Content (e.g., documents, files or a desktop) is presumed fixed in virtual space with the mobile user interface displaying a portion of the content as if viewed through a camera or magnifying glass. Data from motion, distance or position sensors are used to determine the relative position/orientation of the device with respect to the content to select the portion for display. Content elements can be selected by centering the display on the desired portion, obviating the need for cursors and pointing devices (e.g., mouse or touchscreen). Magnification can be manipulated by moving the device away from or towards the user. 3-D content viewing may be enabled by sensing the device orientation and displaying content that is above or below the display in 3-D virtual space.

Method and apparatus for automatically adjusting speaker and microphone gains within a mobile telephone

Abstract: The mobile telephone is provided with the capability for automatically adjusting the gain of a microphone of the telephone based upon the detected noise level in which the cellular telephone is operated. As the noise level increases, the gain of the microphone is automatically decreased, thereby compensating for the natural tendency of telephone users to speak more loudly in noisy environments. Also, by decreasing the microphone gain, any clipping that might otherwise occur as a result of the user speaking more loudly is avoided and the signal-to-noise ratio is not thereby decreased. Furthermore, because the microphone gain decreases, the volume level of the voice of the user as it is output from the other party's telephone is not unduly loud. Hence, the other party need not manually decrease the speaker gain of his or her telephone. In the exemplary embodiment, the cellular telephone includes a digital signal processor configured or programmed to apply the detected noise level to look-up tables relating various noise levels to appropriate speaker and microphone gain levels. Also, in the exemplary embodiment, the mobile telephone includes a speaker and the gain of the speaker is adjusted to increase in response to an increase in the background noise level. A method of automatically adjusting the gain of speaker in a wireless communications device includes the steps of obtaining a digital value representing the available headroom, estimating the background noise level, and adjusting the volume based on the background noise estimate and the available headroom. Thus, for example, the need for manual volume control buttons on a cellular telephone is eliminated.