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..

High efficiency high performance communications system employing multi-carrier modulation

Abstract: Transmitter and receiver units for use in a communications system and configurable to provide antenna, frequency, or temporal diversity, or a combination thereof, for transmitted signals. The transmitter unit includes a system data processor, one or more modulators, and one or more antennas. The system data processor receives and partitions an input data stream into a number of channel data streams and further processes the channel data streams to generate one or more modulation symbol vector streams. Each modulation symbol vector stream includes a sequence of modulation symbol vectors representative of data in one or more channel data streams. Each modulator receives and modulates a respective modulation symbol vector stream to provide an RF modulated signal, and each antenna receives and transmits a respective RF modulated signal. Each modulator may include an inverse (fast) Fourier transform (IFFT) and a cyclic prefix generator. The IFFT generates time-domain representations of the modulation symbol vectors, and the cyclic prefix generator repeats a portion of the time-domain representation of each modulation symbol vector. The channel data streams are modulated using multi-carrier modulation, e.g., OFDM modulation. Time division multiplexing (TDM) may also be used to increase flexibility.

Off-axis properties of silicon and quartz dielectric lens antennas

Abstract: The theoretical far-field patterns and Gaussian-beam coupling efficiencies are investigated for a double-slot antenna placed off aids on extended hemispherical silicon and quartz lenses. Measured off-axis radiation patterns at 250 GHz agree well with the theory. Results are presented that show important parameters versus off-axis displacement: scan angle, directivity, Gaussicity, and reflection loss. Directivity contour plots are also presented and show that near-diffraction limited performance can be achieved at off-axis positions at nonelliptical extension lengths. Some design rules are discussed for imaging arrays on dielectric lens antennas.

Sensor networks based on wireless devices

Abstract: Techniques for using wireless devices to implement sensor networks are described. For cognitive radio, a wireless device obtains measurements for a first system (e.g., a broadcast system) with which the wireless device is not in communication. The wireless device sends the measurements and associated location information and/or timestamps via a second system (e.g., a cellular system). A server receives measurements from a number of wireless devices and determines the coverage of the first system based on the measurements. For other applications, a wireless device obtains sensor information from at least one sensor at the wireless device and sends the sensor information and associated location information and/or timestamps via a wireless system. A server receives the sensor information and associated information from a number of wireless devices, aggregates the sensor information, and constructs a map. The wireless device may develop a user profile based on the sensor information and associated information.

Enhanced physical layer repeater for operation in wimax systems

Abstract: An exemplary method (500) and repeater (110, 210, 300) are described for repeating using a time division duplex (TDD) radio protocol. A signal is transmitted from a first station to a second station using a downlink and an uplink. The signal can be detected with detectors (309, 310, 855, 856) on the uplink or the downlink. The repeater can synchronize to time intervals associated with the detected signal that are measured during an observation period. The signal can be retransmitted from the second station to the first station if the signal is detected on the uplink and re-transmitted from the first station to the second station if the signal is detected on the downlink. A gain value associated with the downlink can be used to establish a gain value associated with the uplink.

Reverse link channel architecture for a wireless communication system

Abstract: A channel structure and mechanisms that support effective and efficient allocation and utilization of the reverse link resources. In one aspect, mechanisms are provided to quickly assign resources (e.g., a supplemental channel) as needed, and to quickly de-assign the resources when not needed or to maintain system stability. The reverse link resources may be quickly assigned and de-assigned via short messages (412, 418) exchanged on control channels on the forward and reverse links. In another aspect, mechanisms are provided to facilitate efficient and reliable data transmission. A reliable acknowledgment/negative acknowledgment scheme and an efficient retransmission scheme are provided. Mechanisms are also provided to control the transmit power and/or data rate of the remote terminals to achieve high performance and avoid instability.