Showing papers by "Qualcomm published in 2001"

Video-based image control system

Abstract: A method of using stereo vision to interface with a computer is provided. The method includes capturing a stereo image, and processing the stereo image to determine position information of an object in the stereo image. The object is controlled by a user. The method also includes communicating the position information to the computer to allow the user to interact with a computer application.

Method and apparatus for measuring and reporting channel state information in a high efficiency, high performance communications system

Abstract: Channel state information (CSI) can be used by a communications system to precondition transmissions between transmitter units and receiver units. In one aspect of the invention, disjoint sub-channel sets are assigned to transmit antennas located at a transmitter unit. Pilot symbols are generated and transmitted on a subset of the disjoint sub-channels. Upon receipt of the transmitted pilot symbols, the receiver units determine the CSI for the disjoint sub-channels that carried pilot symbols. These CSI values are reported to the transmitter unit, which will use these CSI values to generate CSI estimates for the disjoint sub-channels that did not carry pilot symbols. The amount of information necessary to report CSI on the reverse link can be further minimized through compression techniques and resource allocation techniques.

Method and Apparatus for Controlling Transmissions of a Communications System

Abstract: In some aspects, each cell in the communications system can be designed to operate in accordance with a set of back-off factors that identify the reductions in peak transmit power levels for the channels associated with the back-off factors. The back-off factors are defined to provide the required power to a large percentage of the users while reducing the amount of interference. In some other aspects, the cells operate using an adaptive reuse scheme that allows the cells to efficiently allocate and reallocate the system resources to reflect changes in the system. A reuse scheme is initially defined and resources are allocated to the cells. During operation, changes in the operating conditions of the system are detected and the reuse scheme is redefined as necessary based on the detected changes. For example, the loading conditions of the cells can be detected, and the resources can be reallocated and/or the reuse scheme can be redefined. In yet other aspects, techniques are provided to efficiency schedule data transmissions and to assign channels to users. Data transmissions can be scheduled based on user priorities, some fairness criteria, system requirements, and other factors. Users are assigned to available channels based on a number of channel assignment schemes. Channel metrics are also provided, which can be used to prioritize users and for channel assignments.

Asymptotic analysis of proportional fair algorithm

Abstract: It was previously shown (under simplifying assumptions) that the proportional fair algorithm gives equal power and time to users who only differ in their distance from the BS, their fading characteristics being the same (see Holtzman, J.M., Proc. VTC2000-Spring, p.1663-7, 2000). We give here a more general result for two classes of users with different fading characteristics. All other things being equal, the user class with more fading variability gets more throughput with a lower (but not much lower) fraction of time transmitting. We also demonstrate a separability property-the effects of variability and distance from the base station are separable.

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.

Method and apparatus for providing arbitration in a group communication network

Abstract: A method and apparatus for arbitrating between a first communication device having floor control in a group communication network and a second communication device competing for floor control provides receiving a floor-control request from the second communication device, comparing respective priority levels of the first communication device and the second communication device, and granting floor control to the second communication device if the second communication device has a higher or equal priority level. In one embodiment, the controller receives the request for floor control from a push-to-talk (PTT) device.

Base station synchronization for handover in a hybrid GSM/CDMA network

Abstract: A mobile wireless telecommunications system includes base stations (30) of a first type operating according to a first air interface, and base stations (36) of a second type operating according to a second air interface. Methods and apparatus are provided for handing over a mobile station (40) in the system from a first base station (30), which is of the first type, to a second base station (36), which is of the second type. A communications link is established over the first air interface between the mobile station (40) and the first base station (30). Data is received from the mobile station (40) responsive to a signal received by the mobile station (40) over the second air interface from the second base station (36), substantially without breaking the communications link with the first base station. The mobile station (40) is handed over from the first (30) to the second base station (36) responsive to the data received therefrom.

Time-domain transmit and receive processing with channel eigen-mode decomposition for MIMO systems

Abstract: Techniques for processing a data transmission at the transmitter and receiver. In an aspect, a time-domain implementation is provided which uses frequency-domain singular value decomposition and “water-pouring” results to derive time-domain pulse-shaping and beam-steering solutions at the transmitter and receiver. The singular value decomposition is performed at the transmitter to determine eigen-modes (i.e., spatial subchannels) of the MIMO channel and to derive a first set of steering vectors used to “precondition” modulation symbols. The singular value decomposition is also performed at the receiver to derive a second set of steering vectors used to precondition the received signals such that orthogonal symbol streams are recovered at the receiver, which can simplify the receiver processing. Water-pouring analysis is used to more optimally allocate the total available transmit power to the eigen-modes, which then determines the data rate and the coding and modulation scheme to be used for each eigen-mode.

Generating and implementing a communication protocol and interface for high data rate signal transfer

Abstract: not available for EP1423778Abstract of corresponding document: WO03023587A 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.

Adaptive rate control for OFDM communication system

Abstract: Techniques to adaptively control the rate of a data transmission in a wireless (e.g., OFDM) communication system. In an aspect, various types of metrics may be derived and used to select the proper rate for the data transmission. Some types of metrics relate to different characteristics of the communication channel, such as SNR, frequency selectivity, time selectivity, and so on. One type of metric relates to the performance of the data transmission. In another aspect, the various types of metrics may be used in different manners to adaptively control the rate. Some metrics may be used for open-loop control of the rate, other metrics may be used for closed-loop control, and some may be used for both. For example, the channel metrics may be used to determine or select the rate, and the performance metrics may be used to determine whether or not to adjust the rate.

Bit interleaving for orthogonal frequency division multiplexing in the transmission of digital signals

Abstract: In an orthogonal frequency division multiplexing (OFDM) system which uses an outer Reed-Solomon encoder and interleaver an inner convolutional encoder, after the inner convolutional encoding the data bits are interleaved, and then grouped into symbols, each symbol having “m” bits. After grouping, the symbols are mapped to a complex plane using quadrature amplitude modulation (QAM). Thus, bits, not symbols, are interleaved by the inner interleaver. A receiver performs a soft decision regarding the value of each bit in each complex QAM symbol received.

Method and apparatus for measuring channel state information

Abstract: A method and apparatus for transmitting in a multi-antenna communication system (100). Each of a plurality of antennas (116,122) are assigned with a different one of a plurality of groups of sub-bands. The plurality of groups of sub-bands each include a different sub-set of the plurality of sub-bands, where the plurality of sub-bands of a first group are non-contiguous. Transmitting from the plurality of antennas (116) and simultaneously using the plurality of groups of sub-bands, where transmitting from each antenna (116) occurs on the group of sub-bands assigned to the antenna (116). A base station for use in the multi-antenna communication system (100) including a first processor (332) for pre-conditioning transmission data, assigning a plurality of pilot symbols to the plurality of transmit antennas (116), and assigning a plurality of sub-channel sub-sets to the plurality of antennas (116). The plurality of antennas (116) transmit each of the assigned plurality of pilot symbols over their respectiven assigned sub-channel sub-sets.

Method and apparatus for participating in group communication services in an existing communication system

Abstract: A push-to-talk communication device to participate in a group communication net (100) is claimed. The group communication net (100) comprises a controller (104) to manage the group communication net (100) and interface with the push-to-talk communication devices (108, 112 and 116). A processor converts information signals into packet data suitable for transmission over a distributed network. The processor may also have identification information, and updates its identification information when its current identification information has or is about to change. The processor then transmits its new identification information to the controller (104). The push-to-talk devices (108, 112 and 116) also comprise a transmitter to transmit packet data through a first channel to the controller. A receiver receives packet data through a second channel from the controller. The push-to-talk devices (108, 112 and 116) also comprise a user activated mechanism to activate the transmitter when a user of the communication device wishes to transmit packet data to the controller.

Method and apparatus for multiplexing high-speed packet data transmission with voice/data transmission

Abstract: Techniques for transmitting voice/data and packet data services such that packet data transmissions have less impact on voice/data transmissions. In one aspect, voice/data and packet data can be multiplexed within a transmission interval such that the available resources are efficiently utilized. In another aspect, the amount of variation in the total tansmit power from a base station is controlled to reduce degradation to transmissions from this and other base stations. In a specific method for concurrently transmitting a number of types of data, a first data type (e.g., voice, overhead, and some data) and a second data type are respectively processed in accordance with first and second signal processing schemes to generate first and second payloads, respectively. First and second partitions are then defined in a transmission interval. The first and second payloads are time multiplexed into the first and second partitions, respectively, and the multiplexed payloads are transmitted.

Communique wireless subscriber device for a cellular communication network

Abstract: The wireless subscriber device that is operable in a communique system for cellular communication networks operates with existing cellular communication networks to provide communique communication services to subscribers. The wireless subscriber devices used to communicate with the communique system for cellular communication networks are typically full function communication devices that include: WAP enabled cellular telephones, personal digital assistants, Palm Pilots, personal computers, and the like or special communique only communication devices that are specific to communique reception; or MP3 audio players (essentially a radio receiver or communique radio); or an MPEG4 video receiver (communique TV); or other such specialized communication device.

Methods and apparatus for scheduling, serving, receiving media-on-demand for clients, servers arranged according to constraints on resources

Abstract: A media object is scheduled for transmission between a server and a client. The media object is partitioned into segments of blocks, wherein each block is a unit of media for which a client will wait to receive an entire block before playing out the block, and wherein each segment includes an integer number of blocks. One or more channels on which to serve each segment are determined, and a rate at which to serve each segment is determined. Additionally, a schedule pair for each channel is determined. The schedule pair includes a time at which the client may start receiving on the channel and a time at which the client may stop receiving on the channel.

Method and apparatus for canceling pilot interference in a wireless communication system

Abstract: Techniques for canceling pilot interference in a wireless (e.g., CDMA) communication system. A received signal typically includes a number of signal instances (i.e., multipaths). For each multipath desired to be processed, the other multipaths act as interference on the desired multipath. If the pilot is generated based on a known data pattern (e.g., all zeros) and covered with a known channelization code (e.g., a Walsh code of zero), then the pilot in an interfering multipath may be estimated as the spreading sequence at a time offset corresponding to the arrival time of that multipath. The pilot interference from each interference multipath may be estimated based on the spreading sequence for the interfering multipath and the despreading sequence for the desired multipath. The total pilot interference from a number of interfering multipaths may be subtracted from the data component in the desired multipath to provide pilot-canceled data having improved performance.

Method and apparatus for measuring timing of signals received from multiple base stations in a cdma communication system

Abstract: Techniques to more accurately measure the arrival times of transmissions received at a remote terminal from a number of base stations. In one aspect, unassigned finger processors are used to process and measure the arrival times of transmissions from base stations not in the active set. In another aspect, if no finger processors are available for assignment, the arrival times can be measured in the time period between updates of a reference oscillator used for the measurements. In accordance with a method for determining a position of a remote terminal, a first set ofone or more base stations in active communication with the remote terminal is identified and each base station in the first set is assigned at least one finger processor. A second set of one or more base stations not in active communication with the remote terminal is also identified and an available finger processor is assigned to each of at least one base station in the second set. A (signal arrival) time measurement is then provided for further processing. To improve accuracy, the measurements can be performed within a narrow time window.

Methods and apparatuses for using assistance data relating to satellite position systems

Abstract: Methods and apparatuses to obtain an ordered set of satellite positioning system (SPS) satellites, in view of a mobile SPS receiver, via one or two-way communication with the mobile SPS receiver. The mobile SPS receiver receives, in one embodiment, an ordered set of SPS satellites from a cellular transmission site. The ordered set of satellites are those in view of the mobile SPS receiver at a given time; such that the mobile SPS receiver may search for the SPS satellites according to an order of the ordered set of SPS satellites. The order of the ordered set may be obtained by various methods one of which is by minimizing the geometric dilution of precision (GDOP) Satellite; health data may be included in the transmission.

Method and apparatus for broadcasting position location data in a wireless communication system

Abstract: Techniques to efficiently broadcast position location data (PLD) from a base station 120 to a number of terminals 110. In one aspect, PLD messages are classified into groups, and each group is broadcast in a different manner. For example, a first group of messages for PLD related to the base station 120 is broadcast in an unscheduled format, and a second group of messages for PLD related to GPS satellites 130 is broadcast in a scheduled format. In another aspect, a schedule for the second group describes the specific PLD elements selected for broadcast, their broadcast order, and the specific time intervals of their broadcast. The schedule is valid for a particular scheduled time interval, and the scheduling table is broadcast multiple times during the schedule time interval to allow the terminals 110 to quickly retrieve the schedule and ascertain what PLD information is being broadcast and where to look for specific PLD elements.

Method and apparatus for handoff of a wireless packet data services connection

Abstract: A novel method and apparatus is disclosed for performing seamless handoff of a mobile station (MS) between Radio Access Networks (RANs) that use different types of wireless interfaces. The described embodiments enable an MS to handoff between different RANs without causing routing ambiguity, and without substantial loss of network data. Upon moving from the coverage area of a first RAN using a first wireless interface to the coverage area of a second RAN using a second wireless interface, an MS determines whether routing ambiguity may result from the change of RAN and, based on the determination, triggers a re-registration of its network address. A foreign agent (FA) within a packet data serving node (PDSN) monitors network address re-registrations are being created for the same MS. Based on this determination, the PDSN terminates redundant R-P network connections resulting from movement of the MS between different RANs.

Method and apparatus for performing speech frame encoding mode selection in a variable rate encoding system

Abstract: It is an objective of the present invention to provide an optimized method of selection of the encoding mode that provides rate efficient coding of the input speech. It is a second objective of the present invention to identify and provide a means for generating a set of parameters ideally suited for this operational mode selection. Third, it is an objective of the present invention to provide identification of two separate conditions that allow low rate coding with minimal sacrifice to quality. The two conditions are the coding of unvoiced speech and the coding of temporally masked speech. It is a fourth objective of the present invention to provide a method for dynamically adjusting the average output data rate of the speech coder with minimal impact on speech quality.

Method and apparatus for forward power control in a communication system

Abstract: In a data communication system capable of variable rate transmission, the data rate is determined by the largest C/I measurement of the forward link signals as measured at the Access Terminal. In one embodiment, the data transmission is scheduled based on an Access Terminal initiated forward power control, which reduces forward link rate quantization loss due to excess transmit power. The Access Terminal reports to the Access Point the excess C/I estimate for the selected rate. The Access Point then reduces its transmit power by an appropriate amount when serving that Access Terminal. In another embodiment, the data transmission is scheduled based on an Access Point initiated forward power control. The Access Point varies its transmit power over time either randomly or in synchronism with neighboring Access Points in the communication system, which enables an increase in the throughput achieved by users that receive a significant amount of interference.

Method and apparatus for providing secure processing and data storage for a wireless communication device

Abstract: Techniques for providing secure processing and data storage for a wireless communication device. In one specific design, a remote terminal includes a data processing unit, a main processor, and a secure unit. The data processing unit processes data for a communication over a wireless link. The main processor provides control for the remote terminal. The secure unit includes a secure processor that performs the secure processing for the remote terminal (e.g., using public-key cryptography) and a memory that provides secure storage of data (e.g., electronics funds, personal data, certificates, and so on). The secure processor may include an embedded ROM that stores program instructions and parameters used for the secure processing. For enhanced security, the secure processor and memory may be implemented within a single integrated circuit. Messaging and data may be exchanged with the secure unit via a single entry point provided by a bus.

Method and apparatus for controlling transmit power thresholds based on classification of wireless communication subscribers

Abstract: The present invention provides a method and apparatus for allowing a base station or base station controller to adjust transmissions to fixed location subscribers in closed-loop communication systems. In a closed-loop communication system, a base station exchanges signals with both fixed location and mobile user stations. When a user or subscriber initially registers with the base station, the base station determines a status of this subscriber based on, for example, an electronic serial number transmitted to the base station. The base station compares the electronic serial number to a database (Home Location Register) which determines whether the user corresponds to a fixed station or a mobile station. If the user is a fixed station, then the base station lowers nominal and minimum power level thresholds. Based on the lowered thresholds, the base station thereafter transmits forward link signals to the fixed station at a lower power level. As a result, the base station can increase its capacity due to the lower overall power rate.

Direct conversion digital domain control

Abstract: A system and method for a multi-band direct conversion wireless communication receiver is presented. The system incorporates a low noise amplifier (LNA) configured to amplify received RF signals, a local oscillator (LO) configured to output a frequency, and I and Q channel mixers. Each mixer has a first input operatively coupled to the LNA, a second input operatively coupled to the LO output, and an output. The system further includes an adjustment mechanism configured to adjust drive level of the LO depending on a level of jammers detected by the receiver. Thus, the receiver may operate in multiple wireless communication bands and modes and meet the associated specifications.

System and method for providing group communication services

Abstract: A system and method for providing group communication services. Each of a plurality of communication devices coverts information signals into data packets suitable for transmission over a data network, such as the Internet. The data packets are transmitted through the data network to a communications manager. The communications manager acts as a configurable switch, allowing communications from any communication device to be routed to the plurality of communication devices. The communications manager further allows users of other communication systems and devices to participate in group communications with each other.

Method, apparatus, and system for signal prediction

Abstract: An apparatus, method, and system for predicting subframes of GPS signals. The apparatus includes a processor capable of determining whether a subframe is an almanac subframe, setting a timehead and adding it to a TOW, setting a TLM message based on a value of the TOW, generating a CRC for a predicted subframe, and a memory for storing the predicted subframe. The memory may vary in size based on the number of predicted subframes. The processor is further capable of determining whether the value of the TOW is less than the number of seconds in a week, calculating a position of the predicted subframe in the memory, and setting a valid flag.

Method and apparatus for scheduling transmissions in a communication system

Abstract: Method and apparatus for a generalized scheduler for scheduling transmissions in a communications system. The scheduler is defined by a priority function of the channel condition and fairness criteria. The generalized scheduler is adapted to apply a variety of combinations of channel condition metrics and user fairness metrics. The scheduler distinguishes among classes of users, allowing individual processing per class. In one embodiment, a system controller receives a Delivery Priority Parameter (DPP) for each of a plurality of users, and maps each DPP to a corresponding common Mapped Priority Parameter (MPP). An operating point is determined and a corresponding MPP value for each of the users is applied to schedule transmissions.

Battery monitoring system with low power and end-of-life messaging and shutdown

Abstract: A battery monitoring apparatus that senses battery conditions such as low battery charge, end of battery capacity, and end of battery life, and responds by taking actions such as sending messages to a remote site and/or powering down A rechargeable battery is coupled to one or more power-consuming electrical components, including battery monitoring equipment The battery monitoring equipment senses battery charge In response to a low-battery-charge condition, the battery monitoring equipment transmits a battery status message to a remote site and powers-down some of the electrical components Whenever the battery nears the end of its capacity, the monitoring equipment powers down all electronic components and awaits the application of external power The invention also tracks the time required for the battery charge to deplete Charge duration decreases over time, and whenever it reaches a predetermined minimum, the battery monitoring equipment transmits a representative status message to the remote site