Showing papers by "Qualcomm published in 2005"

Cross-layer wireless multimedia transmission: challenges, principles, and new paradigms

Abstract: Wireless networks are poised to enable a variety of existing and emerging multimedia streaming applications. As the use of wireless local area networks spreads beyond simple data transfer to bandwidth-intense, delay-sensitive, and loss-tolerant multimedia applications, addressing quality of service issues become extremely important. Currently, a multitude of protection and adaptation strategies exists in the different layers of the open systems interconnection (OSI) stack. Hence, an in-depth understanding and comparative evaluation of these strategies are necessary to effectively assess and enable the possible trade-offs in multimedia quality, power consumption, implementation complexity, and spectrum utilization that are provided by the various OSI layers. This further opens the question of cross-layer optimization and its effectiveness in providing an improved solution with respect to the above trade-offs. In this article we formalize the cross-layer problem, discuss its challenges, and present several possible solutions. Moreover, we also discuss the impact the cross-layer optimization strategy deployed at one station has on the multimedia performance of other stations. We introduce a new fairness concept for wireless multimedia systems that employs different cross-layer strategies, and show its advantages when compared to existing resource allocation mechanisms used in wireline communications. Finally, we propose a new paradigm for wireless communications based on competition, which allows wireless stations to harvest additional resources or free up resources as well as optimally and dynamically adapt their cross-layer transmission strategies to improve multimedia quality and/or power consumption.

Tracking bimanual movements

Abstract: Hands may be tracked before, during, and after occlusion, and a gesture may be recognized. Movement of two occluded hands may be tracked as a unit during an occlusion period. A type of synchronization characterizing the two occluded hands during the occlusion period may be determined based on the tracked movement of the occluded hands. Based on the determined type of synchronization, it may be determined whether directions of travel for each of the two occluded hands change during the occlusion period. Implementations may determine that a first hand and a second hand are occluded during an occlusion period, the first hand having come from a first direction and the second hand having come from a second direction. The first hand may be distinguished from the second hand after the occlusion period based on a determined type of synchronization characterizing the two hands, and a behavior of the two hands.

Process for modifying offset voltage characteristics of an interferometric modulator

Abstract: An interferometric modulator manufactured according to a particular set of processing parameters may have a non-zero offset voltage. A process has been developed for modifying the processing parameters to shift the non-zero offset voltage closer to zero. For example, the process may involve identifying a set of processing parameters for manufacturing an interferometric modulator that results in a non-zero offset voltage for the interferometric modulator. The set of processing parameters may then be modified to shift the non-zero offset voltage closer to zero. For example, modifying the set of processing parameters may involve modifying one or more deposition parameters used to make the interferometric modulator, applying a current (e.g., a counteracting current) to the interferometric modulator, and/or annealing the interferometric modulator. Interferometric modulators made according to the set of modified processing parameters may have improved performance and/or simpler drive schemes.

A capacitor cross-coupled common-gate low-noise amplifier

Abstract: The conventional common-gate low-noise amplifier (CGLNA) exhibits a relatively high noise figure (NF) at low operating frequencies relative to the MOSFET f/sub T/, which has limited its adoption notwithstanding its superior linearity, input matching, and stability compared to the inductively degenerated common-source LNA (CSLNA). A capacitor cross-coupled g/sub m/-boosting scheme is described that improves the NF and retains the advantages of the CGLNA topology. The technique also enables a significant reduction in current consumption. A fully integrated capacitor cross-coupled CGLNA implemented in 180-nm CMOS validates the g/sub m/-boosting technique. It achieves a measured NF of 3.0 dB at 6.0 GHz and consumes only 3.6 mA from 1.8 V; the measured input-referred third-order intercept ( IIP3) value is 11.4 dBm. The capacitor cross-coupled g/sub m/-boosted CGLNA is attractive for low-power fully integrated applications in fine-line CMOS technologies.

Stability and delay of finite-user slotted ALOHA with multipacket reception

Abstract: The effect of multipacket reception (MPR) on stability and delay of slotted ALOHA based random-access systems is considered. A general asymmetric MPR model is introduced and the medium-access control (MAC) capacity region is specified. An explicit characterization of the ALOHA stability region for the two-user system is given. It is shown that the stability region undergoes a phase transition from a concave region to a convex polyhedral region as the MPR capability improves. It is also shown that after this phase transition, slotted ALOHA is optimal i.e., the ALOHA stability region coincides with the MAC capacity region. Further, it is observed that there is no need for transmission control when ALOHA is optimal i.e., ALOHA with transmission probability one is optimal. Next, these results are extended to a symmetric N>2 user ALOHA system. Finally, a complete characterization of average delay in capture channels for the two-user system is given. It is shown that in certain capture scenarios, ALOHA with transmission probability one is delay optimal for all stable arrival rates. Further, it is also shown that ALOHA with transmission probability one is optimal for stability and delay simultaneously in the two-user capture channel.

Multiplexing of real time services and non-real time services for ofdm systems

Abstract: Transmitter and receiver units for use in an OFDM communications system and configurable to support multiple types of services. The transmitter unit includes one or more encoders, a symbol mapping element, and a modulator. Each encoder receives and codes a respective channel data stream to generate a corresponding coded data stream. The symbol mapping element receives and maps data from the coded data streams to generate modulation symbol vectors, with each modulation symbol vector including a set of data values used to modulate a set of tones to generate an OFDM symbol. The modulator modulates the modulation symbol vectors to provide a modulated signal suitable for transmission. The data from each coded data stream is mapped to a respective set of one or more “circuits”. Each circuit can be defined to include a number of tones from a number of OFDM symbols, a number of tones from a single OFDM symbol, all tones from one or more OFDM symbols, or some other combination of tones. The circuits can have equal size or different sizes. Different circuits can be used for full rate data (e.g., active speech) and low rate data (e.g., silence periods).

Method and apparatus for determining location of a base station using a plurality of mobile stations in a wireless mobile network

Abstract: A method and apparatus for determining a position of a base station in a wireless communication network that includes a mobile station in communication with base stations. A BTS calibration server is networked with the base stations. A BTS calibration program is programmed into a group of mobile stations that have position location capabilities. Using the BTS calibration program, calibration information may be requested by the BTS calibration server, or a session may be initiated by the mobile station. The BTS calibration program also provides privacy features that allow user of the mobile station to prevent it from being used for base station location. If authorized, the BTS calibration program determines the position of the mobile station, and provides calibration information, such as position and base station phase measurements, to the server. The calibration information may be used to calibrate the base station almanac.

Location based service (lbs) system and method for targeted advertising

Abstract: A system and method for providing a location based service to create a social network, comprising activating a feature from a wireless terminal, registering from the wireless terminal with a location based service associated with the feature, creating a profile of a user of the feature, and displaying advertising based on the profile and based on geographic location of the wireless terminal. A Global Positioning System (GPS) may be used to geographically locate active users of a feature and sponsors of advertising. Advertising is displayed based on geographic location of the wireless terminal and sponsor(s) of the advertising being represented on an activity map.

Controlling electromechanical behavior of structures within a microelectromechanical systems device

Abstract: In one embodiment, the invention provides a method for fabricating a microelectromechanical systems device The method comprises fabricating a first layer comprising a film having a characteristic electromechanical response, and a characteristic optical response, wherein the characteristic optical response is desirable and the characteristic electromechanical response is undesirable; and modifying the characteristic electromechanical response of the first layer by at least reducing charge build up thereon during activation of the microelectromechanical systems device

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.

High data rate interface apparatus and method

Abstract: A data interface for transferring digital data between a host and a client over a communication path using packet structures linked together to form a communication protocol for communicating a pre-selected set of digital control and presentation data. The signal protocol is used by link controllers configured to generate, transmit, and receive packets forming the communications protocol, and to form digital data into one or more types of data packets, with at least one residing in the host device and being coupled to the client through the communications path. The interface provides a cost-effective, low power, bi-directional, high-speed data transfer mechanism over a short-range “serial” type data link, which lends itself to implementation with miniature connectors and thin flexible cables which are especially useful in connecting display elements such as wearable micro-displays to portable computers and wireless communication devices.

Power control for a wireless communication system utilizing orthogonal multiplexing

Abstract: Techniques for adjusting transmit power to mitigate both intra-sector interference to a serving base station and inter-sector interference to neighbor base stations are described. The amount of inter-sector interference that a terminal may cause may be roughly estimated based on the total interference observed by each neighbor base station, channel gains for the serving and neighbor base stations, and the current transmit power level. The transmit power may be decreased if high interference is observed by a neighbor base station and increased otherwise. The transmit power may be adjusted by a larger amount and/or more frequently if the terminal is located closer to the neighbor base station observing high interference and/or if the current transmit power level is higher, and vice versa. The intra-sector interference is maintained within an acceptable level by limiting a received SNR for the terminal to be within a range of allowable SNRs.

Desktop telephony system

Abstract: A telephony system providing automated authentication, adaptive navigation, full voice dictation and outbound calling.

Method and apparatus for performing fast power control in a mobile communication system

Abstract: A method and apparatus for controlling transmission power levels in a mobile communication system. The method provides for a closed-loop power control method. A mobile station provides information on the quality of the signal received from the base station, and the base station responds by adjusting the power allocated to that user in a shared base station signal. The transmission power is adjusted initially by a large increment and then ramped down at an increasingly decreasing rate. The mobile station also provides information to the base station as to its relative velocity and the base station adjusts its transmission power in accordance with this velocity information.

Rate Region of the Quadratic Gaussian Two-Encoder Source-Coding Problem

Abstract: We determine the rate region of the quadratic Gaussian two-encoder source-coding problem. This rate region is achieved by a simple architecture that separates the analog and digital aspects of the compression. Furthermore, this architecture requires higher rates to send a Gaussian source than it does to send any other source with the same covariance. Our techniques can also be used to determine the sum rate of some generalizations of this classical problem. Our approach involves coupling the problem to a quadratic Gaussian ``CEO problem.''

Capacity-achieving ensembles for the binary erasure channel with bounded complexity

Abstract: We present two sequences of ensembles of nonsystematic irregular repeat-accumulate (IRA) codes which asymptotically (as their block length tends to infinity) achieve capacity on the binary erasure channel (BEC) with bounded complexity per information bit This is in contrast to all previous constructions of capacity-achieving sequences of ensembles whose complexity grows at least like the log of the inverse of the gap (in rate) to capacity The new bounded complexity result is achieved by puncturing bits, and allowing in this way a sufficient number of state nodes in the Tanner graph representing the codes We derive an information-theoretic lower bound on the decoding complexity of randomly punctured codes on graphs The bound holds for every memoryless binary-input output-symmetric (MBIOS) channel and is refined for the binary erasure channel

Location based service (lbs) system and method for creating a social network

Abstract: A system and method for providing a location based service to create a social network, comprising activating a feature from a wireless terminal, registering from the wireless terminal with a location based service associated with the feature, creating a profile of a user of the feature, and displaying candidates based on the profile and based on the geographic location of the candidates. A Global Positioning System (GPS) may be used to geographically locate active users of a feature. An activity map may be associated with a feature, the activity map displaying active users of the feature.

Method and device for manipulating color in a display

Abstract: Embodiments include methods and devices for controlling the spectral profile and color gamut of light produced by an interferometric display. Such devices include illuminating a display with selected wavelengths of light. Embodiments also include a display comprising separate sections that output different predetermined colors of light. Other embodiments include methods of making the aforementioned devices.

Multiple Frequency Band Operation in Wireless Networks

Abstract: Embodiments for bandwidth allocation methods, detecting interference with other systems, and/or redeploying in alternate bandwidth are described Higher bandwidth channels may be deployed at channel boundaries (410), which are a subset of those for lower bandwidth channels (310), and may be restricted from overlapping Interference may be detected (930) on primary, secondary, or a combination of channels, and may be detected in response to energy measurements (910) of the various channels When interference is detected, a higher bandwidth Basic Service Set (BSS)(100) may be relocated to an alternate channel, or may have its bandwidth reduced to avoid interference Interference may be detected based on energy measured on the primary or secondary channel, and/or a difference between the two An FFT (1010) may be used in energy measurement in either or both of the primary and secondary channels Stations may also monitor messages from alternate systems to make channel allocation decisions Various other aspects are also presented

Interference display cell and fabrication method thereof

Abstract: An optical interference display unit with a first electrode, a second electrode and support structures located between the two electrodes is provided. The second electrode has at least a first material layer and a second material layer. At least one material layer of the two is made from conductive material and the second conductive layer is used as a mask while an etching process is performed to etch the first material layer to define the second electrode.

Position based enhanced security of wireless communications

Abstract: The convenience of a wireless network is tempered by the concern that a rogue device can listen in on the wireless communications. Determining the position of the home device and other devices within range allows the user of the home device to choose the specific wireless devices with which to communicate. The distance to the other devices within wireless communications range is helpful and allows the user to sort between safe and unsafe or rogue devices. Distance can be determined by a variety of methods including use of trusted references, signal strength, and error rate. Once the safe device is selected, the system will then establish a communications path with that device.

Methods and apparatus for use in a wireless communications system that uses a multi-mode base station

Abstract: A multi-mode base station includes a transmit standby mode and an active mode. Transmit standby mode of base station operation is a low power/low interference level of operation as compared to active mode. In transmit standby mode at least some of the synchronization signaling such as pilot tone signaling is reduced in power level and/or rate with respect to the active mode. In transmit standby mode, the base station has no active state registered wireless terminals being serviced but may have some sleep state registered wireless terminals being serviced. Mode transitions from active to transmit standby may be in response to: a detected period of inactivity, scheduling information, base station mode change signals, and/or detected wireless terminal state transition. Mode transitions from transmit standby to active may be in response to: scheduling information, access signals, wake-up signals, hand-off signals, wireless terminal state change signals, and/or base station mode change signals.

Creep Deformation Characteristics of Tin and Tin-Based Electronic Solder Alloys

Abstract: Creep deformation characteristics of pure tin, and Sn-3.5Ag and Sn-5Sb electronic solder alloys, have been studied at various temperatures between ambient and 473 K (homologous temperature 0.58 to 0.85). Power-law relationships between strain rate and stress were observed at most of the temperatures. The stress exponent (n=7.6, 5.0, and 5.0) and activation energy (Q c =60.3, 60.7, and 44.7 kJ/mol) values were obtained in the case of tin, Sn-3.5Ag, and Sn-5Sb respectively. Based on n and Q c values, it is suggested that the rate controlling creep-deformation mechanism is dislocation climb controlled by lattice diffusion in pure tin and Sn-3.5Ag alloy, and viscous glide controlled by pipe diffusion in Sn-5Sb alloy. The results on Sn-3.5Ag bulk material are compared with the initial results on solder bump arrays.

Method and device for multistate interferometric light modulation

Abstract: A multi-state light modulator comprises a first reflector. A first electrode is positioned at a distance from the first reflector. A second reflector is positioned between the first reflector and the first electrode. The second reflector is movable between an undriven position, a first driven position, and a second driven position, each having a corresponding distance from the first reflector. In one embodiment, the three positions correspond to reflecting white light, being non-reflective, and reflecting a selected color of light. Another embodiment is a method of making the light modulator. Another embodiment is a display including the light modulator.

Transmit diversity and spatial spreading for an ofdm-based multi-antenna communication system

Abstract: A multi-antenna transmitting entity transmits data to a single- or multi-antenna receiving entity using (1) a steered mode to direct the data transmission toward the receiving entity or (2) a pseudo-random transmit steering (PRTS) mode to randomize the effective channels observed by the data transmission across the subbands. For transmit diversity, the transmitting entity uses different pseudo-random steering vectors across the subbands but the same steering vector across a packet for each subband. The receiving entity does not need to have knowledge of the pseudo-random steering vectors or perform any special processing. For spatial spreading, the transmitting entity uses different pseudo-random steering vectors across the subbands and different steering vectors across the packet for each subband. Only the transmitting and receiving entities know the steering vectors used for data transmission. Other aspects, embodiments, and features are also claimed and disclosed.

Distributed hierarchical scheduling in an ad hoc network

Abstract: An ad hoc network with distributed hierarchical scheduling is disclosed. In one aspect, stations in a network mesh detect interfering neighbor stations and form interference lists. Stations transmit their interference lists. Scheduling stations schedule allocations for child stations in response to interference lists, received remote allocations, or a combination thereof. Coordination messages are transmitted including frame structure, allocations, and interference lists, among others. In another aspect, an ad hoc mesh network may be organized into a tree topology. In an example wireless backhaul network, this matches traffic flow. Distributed, hierarchical scheduling is provided where parents schedule communication with children while respecting already scheduled transmissions to/from interferers and to/from interferers of their respective children. Procedures to construct interference constraints for distributed, hierarchical scheduling are described, resulting in efficient scheduling and reuse in an ad hoc wireless network, without centralized scheduling. Various other aspects are also disclosed.

Multi-antenna transceiver system

Abstract: A transceiver system includes a first section coupled to a first antenna, a second section coupled to a second antenna, and a radio frequency (RF) unit. The first section includes a transmit path and a first receive path for a first (e.g., GSM) wireless system, a transmit path and a first receive path for a second (e.g., CDMA) wireless system, and a transmit/receive (T/R) switch that couples the signal paths to the first antenna. The second section includes a second receive path for the first wireless system and a second receive path for the second wireless system. The first and second receive paths for the first wireless system are for two frequency bands. The first and second receive paths for the second wireless system are for a single frequency band and provide receive diversity. The transceiver system may include a GPS receive path coupled to a third antenna.

Method and apparatus for carrier customization in communication systems

Abstract: A method of customizing a wireless device to a predetermined configuration is described. A wireless device configured with at least one carrier-specific parameter for a first carrier is modified to access at least one carrier-specific parameter for a second carrier during operation of the wireless device and responsive to a predetermined network switch input received by the wireless device. A carrier customization module system for a wireless device includes a carrier customization module loader executed by the wireless device which is configured with at least one carrier-specific parameter for a first carrier. The loader selects at least one carrier-specific parameter for a second carrier from among one or more carrier-specific parameters during operation of the wireless device and responsive to a predetermined network switch input received by the wireless device. The loader modifies the wireless device to access the second carrier using the selected carrier-specific parameter for the second carrier.

Method and system for packaging a MEMS device

Abstract: A MEMS-based display device is described, wherein an array of interferometric modulators are configured to reflect light through a transparent substrate. The transparent substrate is sealed to a backplate and the backplate can contain electronic circuitry for controlling the array of interferometric modulators. The backplate can provide physical support for device components, such as electronic components which can be used to control the state of the display. The backplate can also be utilized as a primary structural support for the device.

Methods and apparatus for determining, communicating and using information which can be used for interference control purposes

Abstract: Methods and apparatus for collecting, measuring, reporting and/or using information which can be used for interference control purposes. Wireless terminals measure signals transmitted from one or more base stations, e.g., base station sector transmitters. The measured signals may be, e.g., beacon signals and/or pilot signals. From the measured signals, the wireless terminal generates one or more gain ratios which provide information about the relative gain of the communications channels from different base station sectors to the wireless terminal. This information represents interference information since it provides information about the signal interference that will be caused by transmissions from other base station sectors relative to transmissions made by the base station sector to which the wireless terminal is attached. Based on the signal energy measurements and relative gains generated from the energy measures, reports are generated in accordance with the invention and sent to one or more base stations.