Abstract: A method of losslessly compressing and encoding signals representing image information is claimed. A lossy compressed data file and a residual compressed data file are generated. When the lossy compressed data file and the residual compressed data file are combined, a lossless data file that is substantially identical to the original data file is created.

Abstract: Methods and apparatus for amplifier AM and PM predistortion and autocalibration. AM and PM amplifier distortion can be corrected using predistortion. The AM and PM distortion characteristics of the amplifier are determined using an autocalibration technique. The amplifier characteristics can be stored in distinct look up tables. Alternatively, the inverse of the amplifier characteristics can be stored in distinct look up tables. Signals that are to be amplified are characterized in polar format having a phase component with a normalized magnitude and a magnitude component. The phase component can be predistorted by applying the inverse of the PM distortion characteristics to the signal. Similarly, the magnitude component can be predistorted by applying the inverse of the AM distortion characteristics to the signal. The predistorted phase component can be amplified using the previously characterized amplifier.

Abstract: Erasure detection and power control are performed for an intermittently active transport channel with unknown format. A receiver processes each received block and determines whether it passes or fails CRC. For each received block with CRC failure, the receiver performs erasure detection by computing a symbol error rate (SER) and energy of the received block, comparing the computed SER against an SER threshold, comparing the computed energy against an energy threshold, and declaring an erasure if the computed SER is less than the SER threshold and the computed energy exceeds the energy threshold. The SER and energy thresholds may be adjusted based on the average SER and the average energy for prior received blocks with CRC failures. For power control, an SIR target is increased by an UP step whenever an erased block is detected for the transport channel.

Abstract: Techniques for avoiding data loss and reducing registration overhead in a wireless packet data communication system are disclosed. In one embodiment, a mobile station adds each connection to a connection list following registration with the PCF. The mobile station need not reregister a connection included in the connection list when it again enters the PCF's coverage area. In another embodiment, a PDSN maintains a connection table, with one or more connections for each mobile station. The PDSN transmits data to the mobile station along one of the connections. In yet another embodiment, a PDSN transmits on an active connection, if one exists. In yet another embodiment, connections in a connection list or connection table are removed when a corresponding inactivity timer expires. Various other embodiments are also presented.

Abstract: A network operator identifier is used to uniquely identify each network operator to support international roaming. The network operator identifier includes (1) a Mobile Country Code (MCC) that identifies the country in which a network operator belongs and (2) a Network Operator Code (NOC), which may be a Mobile Network Code (MNC), that distinguishes network operators within a given MCC. Each network operator is assigned a unique combination of MCC and NOC that distinctly identifies the network operator, and the network operator identifier can be stored in a single entry in a preferred roaming list. The base stations of each network operator broadcast the network operator identifier in signaling messages. A mobile station receives a signaling message from a base station, obtains the network operator identifier, searches its preferred roaming list for an entry with the network operator identifier, and determines whether or not the current CDMA network is accessible.

Abstract: The virtual device architecture provides physical and logical device drivers for interfacing software programs executing on a microprocessor of the mobile telephone of a wireless communication system with any of a wide variety of hardware devices connectable within the mobile telephone. The logical device drivers convert commands received from the software applications to commands appropriate for use by selected hardware devices. The physical device drivers receive the converted commands from the logical device drivers and in response to the received commands directly control the selected hardware devices. In one example described herein, the logical device drivers provide translation of core commands necessary to control the selected hardware devices and extended commands for enhanced control of the hardware devices. The logical device drivers operate to convert the extended commands into core commands prior to forwarding the commands to the physical device drivers.

Abstract: A data storage area allows a user of a wireless communication device to enter data to be processed and transmitted as a series of dual-tone multi-frequency (DTMF) tones. A wireless communication device transmits call origination over the traffic channel and can transmit DTMF tones over the traffic channel. The user may enter data into a storage area along with an indication that the entered data should be processed as DTMF tones. Data entered as DTMF tones is processed and transmitted over the traffic channel as a series of DTMF tones. A data storage area may have predetermined locations wherein data stored in the predetermined locations are processed as DTMF tones. Alternatively, a data flag or other indicator may be associated with the data to indicate processing as DTMF tones.

Abstract: A velocity estimate is determined from a received signal by counting the number of times a signal in one multipath crosses a predetermined threshold in a given amount of time. A signal is received and a single multipath is extracted from the received signal. Instantaneous envelope values of the extracted multipath are calculated. A plurality of the instantaneous envelope values are used to calculate a running RMS value. A level crossing threshold is determined using the running RMS value. The number of times the instantaneous envelope value crosses the level crossing threshold is counted. The number of level crossings is mapped to a velocity estimate.

Abstract: The frequency error of an oscillator is minimized by characterizing the operating environment of the oscillator. An electronic device monitors parameters that are determined to have an effect on the frequency accuracy of the internal frequency source. Temperature is one parameter known to have an effect on the frequency of the internal frequency source and a primary contributor to device temperature is the RF Power Amplifier (PA). The electronic device collects and stores the activity level of the PA. The effective PA duty cycle over a predetermined period of time is calculated. The LO operating environment is stabilized by operating the PA at the calculated duty cycle when the LO is required to operate in a high stability mode.

Abstract: Techniques for providing an improved position estimate for a device in instances of relatively large dilution of precision. In a method, position estimates for a number of transmitters (e.g., GPS satellites and/or base stations) and a set of initial measurements (e.g., pseudo-ranges) are initially received. An Update Vector for a current device position estimate is computed. Non-convergence of the current device position estimate toward a target position estimate is detected and, if true, the Update Vector is adjusted (e.g., reduced in magnitude by a scaling factor) to increase the likelihood of convergence to the target position estimate. The current device position estimate is then updated based on the (possibly adjusted) Update Vector. Non-convergence may be detected based on the number of iterations performed without reaching the target position estimate and/or phase reversal in two consecutive Update Vectors. The scaling factor may be increased with each detected event indicative of non-convergence.

Abstract: A method and circuit for digital signal processing. The disclosed method and circuit uses a variable length instruction set. A portion of the variable length instructions may be stored in adjacent locations within memory. The beginning and ending of instructions may occur across memory word boundaries. Instructions may contain variable numbers of instruction fragments that cause a particular operation to be performed. The disclosed circuit has a set of three data buses over which data may be exchanged with a register bank and three data memories. Data buses include one wide bus and two narrow buses. The wide bus is coupled to a wide data memory and the two narrow buses are coupled to two narrow data memories. Additionally, the disclosed circuit has a register bank that is accessible by at least two processing units. The disclosed circuit further includes an instruction fetch unit that receives instructions of variable length stored in an instruction memory.

Abstract: A method and apparatus for determining the location of a mobile unit within a cellular system. A synchronized signal at a common phase is generated at each base station in a system. The mobile unit transmits a signal tone. Each base station compares the phase of the signal tone to the common phase of the synchronized signal to produce a phase offset. A system controller compares the difference between the phase offset of a first base station and the phase offset of a second base station and determines the difference in distance between the first base station and the mobile unit and the second base station and said mobile unit defining a hyperbolic or linear curve of locations. The system controller compares the difference between the phase offset of the first base station and the phase offset of a third base station and determines the difference in distance between the first base station and the mobile unit and the third base station and said mobile unit defining a second hyperbolic curve of locations.

Abstract: A method and apparatus for providing an improved soft handoff algorithm in a wireless communication system for third generation code division multiple access (“CDMA”) systems.

Abstract: An apparatus and method for locating a remote station operating in analog mode, and that may not have a sense of network time, using an inverted GPS approach. The invention also enables remote stations operating in analog mode that do not know true GPS time to determine their own location. A time stamp, reflecting the approximate time a satellite range measurement is made, is assigned to the measurement at either the remote station or elsewhere in the network. The difference between true GPS network time and the measurement time is treated as a variable “error” in measurement, the length of which is unknown. This variable error is determined and used in determining the physical location of the remote station.

Abstract: Corrections to a coarse position estimate of the pseudorange receiving device are made based upon knowledge of the amount of error present in inaccurate information (e.g., the old Almanac and/or Ephemeris) used to estimate the coarse position.