Showing papers by "Qualcomm published in 2006"

IEEE 802.22: An Introduction to the First Wireless Standard based on Cognitive Radios

Abstract: In November/2004, we witnessed the formation of the first worldwide effort to define a novel wireless air interface (i.e., MAC and PHY) standard based on Cognitive Radios (CRs): the IEEE 802.22 Working Group (WG). The IEEE 802.22 WG is chartered with the development of a CR-based Wireless Regional Area Network (WRAN) Physical (PHY) and Medium Access Control (MAC) layers for use by license-exempt devices in the spectrum that is currently allocated to the Television (TV) service. Since 802.22 is required to reuse the fallow TV spectrum without causing any harmful interference to incumbents (i.e., the TV receivers), cognitive radio techniques are of primary importance in order to sense and measure the spectrum and detect the presence/absence of incumbent signals. On top of that, other advanced techniques that facilitate coexistence such as dynamic spectrum management and radio environment characterization could be designed. In this paper, we provide a detailed overview of the 802.22 draft specification, its architecture, requirements, applications, and coexistence considerations. These not only form the basis for the definition of this groundbreaking wireless air interface standard, but will also serve as foundation for future research in the promising area of CRs.

Optical flow based tilt sensor

Abstract: A method is described for determining a description of motion of a moving mobile camera to determine a user input to an application. The method may involve capturing a series of images from a moving mobile camera and comparing stationary features present in the series of images. Optical flow analysis may be performed on the series of images to determine a description of motion of the moving mobile camera. Based on the determined motion, a user input to an application may be determined and the application may respond to the user input, for example, by updating a user interface of the application.

Cognitive Radio: An Information-Theoretic Perspective

Abstract: Cognitive radios have been proposed as a means to implement efficient reuse of the licensed spectrum. The key feature of a cognitive radio is its ability to recognize the primary (licensed) user and adapt its communication strategy to minimize the interference that it generates. We consider a communication scenario in which the primary and the cognitive user wish to communicate to different receivers, subject to mutual interference. Modeling the cognitive radio as a transmitter with side-information about the primary transmission, we characterize the largest rate at which the cognitive radio can reliably communicate under the constraint that (i) no interference is created for the primary user, and (ii) the primary encoder-decoder pair is oblivious to the presence of the cognitive radio.

Apparatus and methods of selective collection and selective presentation of content

Abstract: Disclosed are apparatus and methods operable to distribute targeted content. Additionally, disclosed are corresponding apparatus and methods operable to selectively choose and cache selected ones from among the distributed targeted content, and to further choose ones from among the cached content to present on a device. In some aspects, selective caching of content may be based upon a match between predetermined content attribute information and predetermined profile information. Further, in some aspects, an indicator is operable to trigger the selective inclusion of one or more of the cached content in a presentation of other content, which may be based on a match between a desired content attribute associated with the indicator and the respective predetermined content attribute information of the cached content.

Positioning for WLANS and other wireless networks

Abstract: Techniques for positioning access points and terminals in WLANs and other wireless networks are described. For access point positioning, measurements are obtained for at least one access point in a WLAN. The measurements may be based on transmission sequences (e.g., beacon frames) transmitted periodically by each access point. The measurements may be made by multiple terminals at different locations or a single mobile terminal at different locations. The location of each access point is determined based on the measurements and known locations of the terminal(s). For terminal positioning, measurements for at least one access point in a WLAN are obtained. The location of the terminal is determined based on the measurements and known location of each access point. The measurements may be round trip time (RTT) measurements, observed time difference (OTD) measurements, time of arrival (TOA) measurements, signal strength measurements, signal quality measurements, etc.

Method and apparatus for communicating emergency information using wireless devices

Abstract: A method and apparatus for providing emergency notification by a wireless mobile device in response to triggering a sensor. A detection system, which may be located within a vehicle, comprises one or more sensors configured to sense an emergency event and transmit a message via a wireless link regarding the emergency event. For example, the wireless mobile device may be programmed to call a predetermined emergency number such as E911, and transmit data including position and other information from the mobile device to the emergency number in response to the received message.

Methods and devices for interworking of wireless wide area networks and wireless local area networks or wireless personal area networks

Abstract: Embodiments describe registration in a wireless communication system. A method includes wirelessly transmitting over a WWAN a first registration message from a mobile device, wirelessly transmitting through the WWAN a second registration message to a WLAN access point and receiving at the mobile device access through the WLAN access point. According to another embodiment is a method for constructing a self-configuring ad-hoc network. The method can include receiving a GPS coordinate from a WWAN channel node at a management system and creating an initial topography based at least in part on the GPS coordinate to achieve a network connectivity with diverse routes between a plurality of nodes.

Information Theory and Mixing Least-Squares Regressions

Abstract: For Gaussian regression, we develop and analyze methods for combining estimators from various models. For squared-error loss, an unbiased estimator of the risk of the mixture of general estimators is developed. Special attention is given to the case that the component estimators are least-squares projections into arbitrary linear subspaces, such as those spanned by subsets of explanatory variables in a given design. We relate the unbiased estimate of the risk of the mixture estimator to estimates of the risks achieved by the components. This results in simple and accurate bounds on the risk and its estimate, in the form of sharp and exact oracle inequalities. That is, without advance knowledge of which model is best, the resulting performance is comparable to or perhaps even superior to what is achieved by the best of the individual models. Furthermore, in the case that the unknown parameter has a sparse representation, our mixture estimator adapts to the underlying sparsity. Simulations show that the performance of these mixture estimators is better than that of a related model-selection estimator which picks a model with the highest weight. Also, the connection between our mixtures with Bayes procedures is discussed

Voip emergency call support

Abstract: Techniques to support emergency voice-over-Internet Protocol (VoIP) calls are described. The techniques may be used for various 3GPP and 3GPP2 networks, various location architectures, and various types of User Equipment (UE). A UE communicates with a visited network to send a request to establish an emergency VoIP call. The UE interacts with a location server instructed by the visited network to obtain a first position estimate for the UE. The UE performs call setup via the visited network to establish the emergency VoIP call with a PSAP, which may be selected based on the first position estimate. The UE may thereafter perform positioning with the location server to obtain an updated position estimate for the UE, e.g., if requested by the PSAP.

Mobile communication system with position detection to facilitate hard handoff

Abstract: A system for facilitating handoff adapted for use with a telecommunications network. The system includes position equipment for determining the location of a mobile transceiver within a region containing a first cell and a second cell. A comparison circuit compares the location with a predetermined handoff area within the region and provides a control signal in response thereto. A handoff initiation circuit initiates handoff of the mobile transceiver between the first cell and the second cell in response to the control signal. In a specific embodiment, the handoff is a hard handoff. The position equipment includes Global Positioning System (GPS) equipment including a mobile unit GPS receiver and signal interface. The comparison circuit includes a positional database that stores latitudinal and longitudinal information corresponding to the predetermined handoff area. The comparison circuit also includes a Code Division Multiple Access selector. The selector begins tracking the position of the mobile transceiver when it is within a predetermined range of the predetermined handoff area. In a specific embodiment, the handoff initiation circuit includes a base station controller. The position equipment includes a base station positional detection system and a mobile unit positional detection system for determining the location of the mobile transceiver. The position database has map information depicting the coverage area of the first and second cells and the predetermined handoff area. The selector runs software for comparing the location to the map information and providing the control signal when the location is within the predetermined handoff area. The base station includes and implements instructions for completing hard handoff in response to the control signal.

Advanced high-κ dielectric stacks with polySi and metal gates: recent progress and current challenges

Abstract: The paper reviews our recent progress and current challenges in implementing advanced gate stacks composed of high-κ dielectric materials and metal gates in mainstream Si CMOS technology. In particular, we address stacks of doped polySi gate electrodes on ultrathin layers of high-κ dielectrics, dual-workfunction metal-gate technology, and fully silicided gates. Materials and device characterization, processing, and integration issues are discussed.

Peer-to-peer communication in ad hoc wireless network

Abstract: For a peer-to-peer call in an ad hoc wireless network, a wireless device performs discovery of a target wireless device, performs authentication of the target wireless device and generates a session key (e.g., using a pre-shared key or a certificate provisioned on the wireless device), forms an ad hoc wireless network with the target wireless device, and communicates peer-to-peer with the target wireless device via the ad hoc wireless network. The wireless device may perform discovery with a list of identifiers for wireless devices designated to communicate with this wireless device. The wireless device may derive a service set identifier (SSID) used to identify the ad hoc wireless network based on its user-specific identifier (e.g., its phone number) and/or a user-specific identifier for the target wireless device. The wireless device may also performs IP address discovery using the user-specific identifier for the target wireless device.

Multi-carrier operation in data transmission systems

Abstract: Multi-carrier point-to-multi-point CDMA system implementation reduces hardware changes in legacy single-carrier systems. The number of common downlink channels, such as timing/synchronization and paging channels, is reduced by designating an anchor carrier for transmitting these channels. Procedures for adding carriers and carrier acquisition are simplified through common carrier timing, signaling by the network to the user equipment (UE) of timing offsets and scrambling code selection, and other measures. Channel reuse is employed to minimize changes in asymmetric systems with different numbers of uplink and downlink carriers. Channel Quality Indicator (CQI) field is divided into multiple subfields to enable transmission of multiple CQIs and ACK/NACK indicators on one uplink carrier. Joint and separate scheduling schemes are shown for concurrent scheduling of a data stream transmission to a UE via multiple downlink carriers.

Performance of power detector sensors of DTV signals in IEEE 802.22 WRANs

Abstract: Sensing is the most important component in any cognitive radio system. The IEEE 802.22 Working Group (WG) is formulating the first worldwide standard for cognitive radios to operate in the television (TV) bands. In order for this standard to succeed, it is imperative that IEEE 802.22 systems employ an effective sensing mechanism to detect the presence of television signals so that it can opportunistically access those bands that are not currently used by TV transmitters. In this paper we highlight the simulation methodology used in the IEEE 802.22 WG and study the performance of the power detector.

Robust separation of speech signals in a noisy environment

Abstract: A method for improving the quality of a speech signal extracted from a noisy acoustic environment is provided. In one approach, a signal separation process (180) is associated with a voice activity detector (185). The voice activity detector (185) is a two-channel (178,182) detector, which enables a particularly robust and accurate detection of voice activity. When a speech is detected, the voice activity detector generates a control signal (411). The control signal (411) is used to activate, adjust, or control signal separation processes or post -processing operations (195) to improve the quality of the resulting speech signal. In another approach, a signal separation process (180) is provided as a learning stage (752) and an output stage (756). The learning stage (752) aggressively adjus to current acoustic conditions and passes coefficients to the output stage (756). The output stage (756) adapts more slowly and generates a speech-content signal (181,770) and a noise dominant signal (407,773). When the learning stage (752) becomes unstable only the learning stage (752) is reset, allowing the output stage (756) to continue outputting a high quality speech signal.

Method and apparatus for monitoring usage patterns of a wireless device

Abstract: Apparatus and methods for monitoring usage patterns of a wireless device may include a usage monitoring and reporting module operable to monitor and log usage on a wireless device based on a received usage configuration. Further, based on the usage configuration, the wireless device may forward the log to another device operable to analyze the log and generate a usage pattern report viewable by an authorized user.

Scalability techniques based on content information

Abstract: Apparatus and methods of using content information for encoding multimedia data are described. A method of processing multimedia data includes classifying content of multimedia data, and encoding the multimedia data in a first data group and in a second data group based on the content classification, wherein the first data group comprises a coefficient and the second data group comprises a first differential refinement associated with the first data group coefficient. An apparatus for using content information for encoding multimedia data includes a content classifying module configured to classify content of multimedia data and provide content classification data, and an encoder configured to encode the multimedia data in a first data group and in a second data group based on the content classification, wherein the first data group comprises a coefficient and the second data group comprises a first differential refinement associated with the first data group coefficient.

Selective virtual antenna transmission

Abstract: Techniques for transmitting data from virtual antennas instead of physical antennas are described. Each virtual antenna may be mapped to some or all physical antennas by a different mapping. The performance of different sets of at least one virtual antenna is evaluated based on one or more metrics such as signal quality, throughput, overall rate, and so on. The virtual antenna set with the best performance is selected for use. If the virtual antenna selection is performed by the receiver, then channel state information for the selected virtual antenna set may be sent to the transmitter. The channel state information may convey the selected virtual antenna(s), the signal quality or rate(s) for the selected virtual antenna(s), one or more preceding matrices used to form the selected virtual antenna(s), and so on. The transmitter and/or receiver use the selected virtual antenna(s) for data transmission.

System and method for scheduling content updates in a content-based application

Abstract: Described are various mechanisms and techniques for influencing or controlling a content update schedule for a content-based software application on a mobile device. A content server issues one or more commands to the mobile device that establish a content update schedule for the mobile device. The mobile device then performs content update sessions with the content server based on that schedule. During any one or more refresh sessions, the content server delivers another command to establish a new content update schedule. This system provides the advantage of allowing the content server to regulate how frequently the mobile device retrieves new content.

Hybrid-orientation technology (HOT): opportunities and challenges

Abstract: At the onset of innovative device structures intended to extend the roadmap for silicon CMOS, many techniques have been investigated to improve carrier mobility in silicon MOSFETs. A novel planar silicon CMOS structure, seeking optimized surface orientation, and hence carrier mobilities for both nFETs and pFETs, emerged. Hybrid-orientation technology provides nFETs on (100) surface orientation and pFETs on [110] surface orientation through wafer bonding and silicon selective epitaxy. The fabrication processes and device characteristics are reviewed in this paper.

Germanium channel MOSFETs: opportunities and challenges

Abstract: This paper reviews progress and current critical issues with respect to the integration of germanium (Ge) surface-channel MOSFET devices as well as strained-Ge buried-channel MOSFET structures. The device design and scalability of strained-Ge buried-channel MOSFETs are discussed on the basis of our recent results. CMOS-compatible integration approaches of Ge channel devices are presented.

Dynamic resource matching system

Abstract: A method, apparatus, and system are provided for implementing resource and/or location-based matching services between a wireless terminal (e.g., mobile phone) user and one or more resources. A novel infrastructure supports resource and/or location based matching services over a wireless network. A back-end system includes a database, server, and match engine that are configured match a user with one or more resources based on the user's characteristics, preferences, and/or location. Such resources include (1) other users, (2) targeted advertising, (3) businesses/networking opportunities, and/or (4) locate a nearby service or store. A flexible database architecture supports application-specific resources which facilitate the deployment of various matching services. Application developers are thus able to implement different resource-matching applications for wireless devices through a common back-end infrastructure. Additionally, the match engine may include a feedback mechanism that permits the match engine to learn a user's preferences.

Methods and device for data alignment with time domain boundary

Abstract: Apparatus and methods of using content information for encoding multimedia data are described. A method of processing multimedia data includes obtaining content information of multimedia data, and encoding the multimedia data so as to align a data boundary with a frame boundary in a time domain, wherein said encoding is based on the content information. In another aspect, a method of processing multimedia data includes obtaining a content classification of the multimedia data, and encoding blocks in the multimedia data as intra-coded blocks or inter-coded blocks based on the content classification to increase the error resilience of the encoded multimedia data. Apparatus that can process multimedia data described in these methods are also disclosed.

Method and apparatus for packet communications in wireless systems

Abstract: Techniques for transmitting and receiving data in an efficient manner to potentially improve capacity for a wireless network and achieve power savings for a wireless device are described. The techniques utilize a Continuous Packet Connectivity (CPC) mode comprised of multiple (e.g., two) discontinuous transmission (DTX) modes and at least one (e.g., one) discontinuous reception (DRX) mode. Each DTX mode is associated with different enabled uplink subframes usable for transmission from the wireless device to the network. Each DRX mode is associated with different enabled downlink subframes usable by the network for transmission to the wireless device. The wireless device may send signaling and/or data on the enabled uplink subframes and may receive signaling and/or data on the enabled downlink subframes. The wireless device may power down during non-enabled subframes to conserve battery power. Mechanisms to quickly transition between the DTX and DRX modes are described.

Weight Distribution of Low-Density Parity-Check Codes

Abstract: We derive the average weight distribution function and its asymptotic growth rate for low-density parity-check (LDPC) code ensembles. We show that the growth rate of the minimum distance of LDPC codes depends only on the degree distribution pair. It turns out that capacity-achieving sequences of standard (unstructured) LDPC codes under iterative decoding over the binary erasure channel (BEC) known to date have sublinearly growing minimum distance in the block length

Method and apparatus for flow control of data in a mesh network

Abstract: Flows admitted to a mesh node may be controlled through contention access parameters. The admitting node may determine a desired transmission opportunity duration, and a transmission opportunity frequency. Furthermore, the node may achieve the flow rate and delay bound requirements of the admitted flow based at least in part upon the desired transmission opportunity duration, and the transmission opportunity frequency. The data rate and the access frequency of the admitted node may be monitored at the physical access level. The flow rate requirement may be accomplished based at least in part upon an adjustment to the transmission opportunity duration. The delay bound requirement may be accomplished at least in part upon manipulation of the contention access parameters. The transmission opportunity duration and the access parameters may be determined by the upstream admitting nodes, which may reduce congestion near mesh portals, and accomplish increased data transfer.

Pilot signal transmission for an orthogonal frequency division wireless communication system

Abstract: Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/ or biasing from different mobile stations over the same frequencies and in the same time slots.

Method and apparatus for transmitting data in a time division duplexed (tdd) communication system

Abstract: Techniques to process data for transmission in a time division duplexed (TDD) communication system. In one aspect, the frequency response of a forward link is estimated at a base station based on reverse link transmissions (e.g., pilots) from a terminal. Prior to a data transmission on the forward link, the base station determines a reverse transfer function based on the pilots transmitted by the terminal, “calibrates” the reverse transfer function with a calibration function to derive an estimate of a forward transfer function, and preconditions modulation symbols based on weights derived from the forward transfer function. In another aspect, the terminal estimates the “quality” of the forward link and provides this information to the base station. The base station then uses the information to properly code and modulate data prior to transmission such that the transmitted data can be received by the terminal at the desired level of performance.

Method and apparatus for maintaining a fingerprint for a wireless network

Abstract: The disclosure is directed to a mobile communication device that measures characteristics or attributes of a first communications network that vary according to physical location within that first communications network to create a fingerprint, or signature, of a location within the first communications network. When the fingerprint of the current location of the mobile device is created it can be compared to a known fingerprint associated with a second communication network to determine the mobile device's proximity to the second communications network. Furthermore, the second and subsequent fingerprint that are generated for a particular communications network can be used to modify the stored fingerprint so as to refine it to improve detecting the proximity to the communications network.

Asymptotic analysis of multistage cooperative broadcast in wireless networks

Abstract: Cooperative broadcast aims to deliver a source message to a locally connected network by means of collaborating nodes. In traditional architectures, node cooperation has been at the network layer. Recently, physical layer cooperative schemes have been shown to offer several advantages over the network layer approaches. This form of cooperation employs distributed transmission resources at the physical layer as a single radio with spatial diversity. In decentralized cooperation schemes, collaborating nodes make transmission decisions based on the quality of the received signal, which is the only parameter available locally. In this case, critical parameters that influence the broadcast performance include the source/relay transmission powers and the decoding threshold (the minimum signal-to-noise ratio (SNR) required to decode a transmission). We study the effect of these parameters on the number of nodes reached by cooperative broadcast. In particular, we show that there exists a phase transition in the network behavior: if the decoding threshold is below a critical value, the message is delivered to the whole network. Otherwise, only a fraction of the nodes is reached, which is proportional to the source transmit power. Our approach is based on the idea of continuum approximation, which yields closed-form expressions that are accurate when the network density is high.