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..

Computing device that determines and uses applied pressure from user interaction with an input interface

Abstract: A computing device processes input by determining one or more inputs corresponding to a user interacting with an input interface. In an embodiment, the input interface may correspond to a button state or to a multi-state input interface. A value corresponding to an amount of pressure applied by the user is determined on the computing device. The value is determined during an instance or duration in which the user is interacting with the input interface. The value for the applied pressure is determined apart from the input. In one embodiment, the value is determined using a force sensor that is separate from the input interface. An operation is then performed that is responsive to the determined amount of pressure, as well as to the one or more inputs.

Multiple antenna MMSE based downlink precoding with quantized feedback or channel mismatch

Abstract: In this paper, we consider the downlink of a multiuser wireless communication system with multiple antennas at the base station and users each with a single receive antenna. It is known that when channel state information (CSI) is available at the transmitter a large performance gain can be achieved. In a system employing time-division duplexing (TDD), CSI can be obtained at the base station if there is reciprocity between the forward and reverse channels. CSI can also be conveyed from the users to the base station via a limited-rate feedback channel in a frequency-division duplexing (FDD) system. In any case, channel estimation errors are inevitable due to the presence of background noise in the estimated signal and due to the finite number of feedback bits used in a limited-rate feedback system model. In this paper, we first consider the general case when partial CSI is available at the transmitter. We derive an MMSE based precoding technique that considers channel estimation errors as an integral part of the system design. Using rate-distortion theory and the generalized Lloyd vector quantization algorithm, we then specialize our results for the more practical limited-rate feedback system model. Compared to previously proposed precoding techniques such as channel inversion and regularized channel inversion, it is shown that the proposed precoding technique significantly improves the average bit error rate (BER) in the system. Furthermore, the performance of the proposed technique is investigated in the high signal-tonoise ratio (SNR) regime. It is shown that the proposed technique suffers from a ceiling effect that asymptotically limits the system performance.

Multi-mode power amplifiers

Abstract: Multi-mode power amplifiers that can support multiple radio technologies and/or multiple frequency bands are described. In one exemplary design, a first linear power amplifier supporting multiple radio technologies may be used to amplify a first RF input signal (e.g., for low band) and provide a first RF output signal. A second linear power amplifier also supporting the multiple radio technologies may be used to amplify a second RF input signal (e.g., for high band) and provide a second RF output signal. Each linear power amplifier may include multiple (e.g., three) chains coupled in parallel. Each chain may be selectable to amplify an RF input signal and provide an RF output signal for a respective range of output power levels. An RF input signal may be a phase modulated signal or a quadrature modulated signal and may be pre-distorted to account for non-linearity of the power amplifier.

A noise optimization technique for integrated low-noise amplifiers

Abstract: Based on measured four-noise parameters and two-port noise theory, considerations for noise optimization of integrated low-noise amplifier (LNA) designs are presented. If arbitrary values of source impedance are allowed, optimal noise performance of the LNA is obtained by adjusting the source degeneration inductance. Even for a fixed source impedance, the integrated LNA can achieve near NF/sub min/ by choosing an appropriate device geometry along with an optimal bias condition. An 800 MHz LNA has been implemented in a standard 0.24 /spl mu/m CMOS technology. The amplifier possesses a 0.9 dB noise figure with a 7.1 dBm third-order input intercept point, while drawing 7.5 mW from a 2.0 V power supply, demonstrating that the proposed methodology can accurately predict noise performance of integrated LNA designs.

Registration and access control in femto cell deployments

Abstract: Systems and methodologies are described that facilitate distributing and/or utilizing a Closed Subscriber Group (CSG) Identifier (ID) that identifies a CSG corresponding to a base station and a CSG indication that distinguishes between the base station permitting access to members of the CSG and permitting access to members and non-members of the CSG For instance, the CSG ID can uniquely identify the CSG corresponding to the base station A mobile device can receive the CSG ID and the CSG indication from the base station Further, the received CSG ID can be compared to CSG IDs included in an allowed CSG list to recognize whether the mobile device is a member or a non-member of the CSG Moreover, a preference for selecting the base station as compared to a disparate base station can be generated as a function of the received CSG ID and CSG indication