Showing papers by "Qualcomm published in 1999"

Method and apparatus for automatic event detection in a wireless communication system

Abstract: Apparatus and method for determining when a vehicle (108) has arrived or departed from a planned or an unplanned stop, while minimizing or completely eliminating driver intervention. The apparatus comprises a mobile communication terminal (202) located onboard a vehicle (108) for receiving destination information, generally using wireless means, from a central facility or hub (104). A speedometer (210) also located onboard the vehicle (108) determines the speed of the vehicle and a position sensor (212) onboard the vehicle (108) determines the vehicle position. The vehicle speed and position are provided to a processor (206), also located onboard the vehicle (108), which uses the speed and position information to determine a vehicle arrival or departure from a planned or unplanned stop. The processor (206) generates an indication of the event, either arrival or departure, directly to the central facility (104), to the vehicle operator, or both.

System and method for determining the position of a wireless cdma transceiver

Abstract: An apparatus and method to determine a position of a mobile wireless transceiver. The invention merges GPS position location and wireless communication technologies to achieve a precise position location in dense urban and other environments when line-of-sight to the satellites is somewhat obscured. The inventive apparatus and method use signals from only two GPS satellites (60, 70, 80, 90) and the serving terrestrial base station. In a most general sense, the inventive method includes the steps of receiving at a base station (10) a first signal transmitted from a first GPS satellite and a second signal transmitted from a second GPS satellite. The mobile's transmitter (200) and receiver (100) are adapted to receive these GPS signals as well and transmit a third signal to the base station in response thereto. The base station (10) receives the third signal and uses it to calculate the position of the wireless unit (20).

Efficient iterative decoding

Abstract: Apparatus for iterative decoding of a sequence of signal packets coded in accordance with a multi-component coding scheme. The apparatus includes a plurality of decoders (68, 70), each of which performs a respective different decoding method on one of the signal packets, such that the plurality of decoders operate substantially concurrently. Iterative decoding may be stopped if a predetermined threshold maximum number of iterations is reached, or if the previous two decoder iterations have satisfactory cyclic redundancy checks (CRC), or if the input frame buffer to the decoder is filled to within a predefined percentage of its storage capacity.

Cellular communication system with common channel soft handoff and associated method

Abstract: A cellular communications system comprising: a mobile unit which designates an active set of base stations; a base station; and a base station controller which puts the base stations in the active set in common channel soft handoff.

Wireless push-to-talk internet broadcast

Abstract: A wireless telephone (302) digitizes the voice of the user in response to the depression of a push-to-talk button (110), either physical or virtual. It sends the digitized voice, in data mode, to a base station (308). The base station places the data, through the Internet, or an Intranet or Extranet, on a server (312). Other wireless phones (304-306) recover the data from the server through the same (308) or different (310) base station, through the Internet, Intranet, or Extranet, and convert the data back to digitized voice. The base stations transmit the digitized voice to other wireless telephones (306), which convert them back to voice in response to the recognition of voice frames on the data channel by the CODEC manager software. Networked computers (314) may be configured to emulate a combined base station and wireless telephone. The server can dynamically designate any wireless telephone (or landline emulation) as the broadcaster, and can dynamically configure any set of telephones/emulations as the receivers of the broadcast.

Method and apparatus for efficient GPS assistance in a communication system

Abstract: A method and apparatus for efficiently transmitting location assistance information to a mobile communication device over a control channel with a minimal impact on the capacity of the control channel. A position location server provides a difference between satellite locations which have been computed using Almanac data and then Ephemeris data. Sending only the difference between the locations and satellite clock corrections computed using the two different data types, the total amount of information to be transmitted to a mobile communication device is significantly reduced. Furthermore, by providing rate of change information, the method and apparatus allows the location assistance information to remain valid for a relatively long time after it is has been received by the mobile communication device.

IP mobility support using proxy mobile node registration

Abstract: A system and method for performing mobile node registration. The system comprises a terminal device (102) for transmitting packetized data, and a wireless communication device (104) coupled to said terminal device for monitoring said packetized data for an Internet Protocol (IP) address contained in an IP address request. The wireless communication device (104) initiates mobile node registration (512) using said IP address if said IP address request is for a static IP address. The wireless communication device prevents (417) the terminal device from sending or receiving packetized data when initiating mobile node registration, and allows said terminal device to send and received packetized data upon completion of mobile node registration. As a result, the mobile node registration occurs transparently to the terminal device, obviating the need for the terminal device to have its own Mobile IP support.

Characterization of spectral regrowth in microwave amplifiers based on the nonlinear transformation of a complex Gaussian process

Abstract: A statistical technique is presented for the characterization of spectral regrowth at the output of a nonlinear amplifier driven by a digitally modulated carrier in a digital radio system. The technique yields an analytical expression for the autocorrelation function of the output signal as a function of the statistics of the quadrature input signal transformed by a behavioral model of the amplifier. The amplifier model, a baseband equivalent representation, is derived from a complex radio-frequency envelope model, which itself is developed from readily available measured or simulated amplitude modulation-amplitude modulation and amplitude modulation-phase modulation data. The technique is used in evaluating the spectral regrowth for a CDMA signal.

Method and apparatus for automatically adjusting speaker and microphone gains within a mobile telephone

Abstract: The mobile telephone is provided with the capability for automatically adjusting the gain of a microphone of the telephone based upon the detected noise level in which the cellular telephone is operated. As the noise level increases, the gain of the microphone is automatically decreased, thereby compensating for the natural tendency of telephone users to speak more loudly in noisy environments. Also, by decreasing the microphone gain, any clipping that might otherwise occur as a result of the user speaking more loudly is avoided and the signal-to-noise ratio is not thereby decreased. Furthermore, because the microphone gain decreases, the volume level of the voice of the user as it is output from the other party's telephone is not unduly loud. Hence, the other party need not manually decrease the speaker gain of his or her telephone. In the exemplary embodiment, the cellular telephone includes a digital signal processor configured or programmed to apply the detected noise level to look-up tables relating various noise levels to appropriate speaker and microphone gain levels. Also, in the exemplary embodiment, the mobile telephone includes a speaker and the gain of the speaker is adjusted to increase in response to an increase in the background noise level. A method of automatically adjusting the gain of speaker in a wireless communications device includes the steps of obtaining a digital value representing the available headroom, estimating the background noise level, and adjusting the volume based on the background noise estimate and the available headroom. Thus, for example, the need for manual volume control buttons on a cellular telephone is eliminated.

Data center for providing subscriber access to data maintained on an enterprise network

Abstract: A data center for providing access to subscriber information from a remote enterprise network in real-time is presented. The data center includes a data network interface system for interfacing with a data network and a login system, which includes a login server and a data center messaging server. The login server receives a request inputted by a subscriber on a remote access device across the data network to access the subscriber information and authenticates the subscriber and the remote device, while the data center messaging server hosting the subscriber information. Upon authenticating the subscriber and the remote device, the login server, accesses the subscriber information on the data center messaging server and provides the subscriber information to the remote access device in response to the received request.

Method and apparatus for increasing the sensitivity of a global positioning satellite receiver

Abstract: Method and apparatus providing enhanced sensitivity for GPS receivers (400, 500, 600, 700) by allowing coherent integration of a correlation over several code periods of a GPS signal in one embodiment, and by performing a time to frequency domain conversion to the output from a correlation processor (507) in a second embodiment. In the case in which coherent integration is performed over several code periods, advantage is taken of the fact that CDMA cellular telephone base stations transmit information that allows the receiver to determine GPS time before beginning a GPS signal acquisition process. The integration can be expanded to include code periods from more than one bit period, if the GPS receiver (400, 500, 600, 700) takes advantage of the fact that known bit patterns are transmitted at particular times within the transmission from a GPS satellite. If no base station is within range, then the output from a correlator (507) that integrates a correlation over one code period is used to generate values that are input to a discrete time domain to frequency domain transform processor (511). The output from the transform processor (511) will indicate the presence of a signal from a particular satellite and the offset between locally generated signal and the received GPS signal.

Method and apparatus for providing wireless communication system synchronization

Abstract: When insufficient traffic is present in the network to maintain synchronization in this manner, other methods must be used. One approach involves making direct measurements of the timing between base stations (602, 604). This is accomplished in one of two ways. The base may interrupt its transmissions on all sectors for a short interval during which it determines the time of arrival of signals from other base stations (602, 604). Given knowledge of the other base station locations, time errors relative to all other base stations (602, 604) may be derived. Alternatively, the base may send a short signal at high power in the mobile transmit band. This time-of-arrival of this signal is measured by the surrounding base stations and the time errors between pairs of base stations are computed. In some cases, a base station (602, 604) may be isolated sufficiently from all other base stations in the network such that direct base-to-base measurement is not viable. In this case, a fixed mobile (606) is placed at a location in the handoff region between the isolated cell and another cell in the network. The fixed mobile (606) either performs measurements of base station pilots on command of the base and reports the timing information, or sends a burst transmission at a specified time and power level to be measured by the base stations.

Method and apparatus for rapid assignment of a traffic channel in digital cellular communication systems

Abstract: A method and apparatus for rapidly assigning traffic channels to a plurality of mobile stations in a wide area high-speed packet data cellular communication system. Mobile stations transmit access probes on randomly selected access channels to selected base stations to initiate traffic channel assignments. The access probe comprises a pilot preamble, a traffic channel request, and a pilot/data request channel (DRC). The pilot preamble allows the selected base station to easily detect the access probe transmission. The traffic channel request includes data that identifies the mobile station. Immediately after transmitting the traffic channel request, the mobile station begins communicating with the base station on both the forward and reverse communication links. The selected base station immediately supervises the mobile station's transmission power. The mobile station selects from a group of available power control sub-channels. The mobile station selects an available channel and an associated power control sub-channel from the list.

Off-line broadband network interface

Abstract: A network interface is presented that receives packet data from a shared medium and accomplishes the signal processing required to convert the data packet to host computer formatted data separately from receiving the data packet. The network interface receives the data packet, converts the analog signal to a digitized signal, and stores the resulting sample packet in a storage queue. An off-line processor, which may be the host computer itself, performs the signal processing required to interpret the sample packet. In transmission, the off-line process converts host-formatted data to a digitized version of a transmission data packet and stores that in a transmission queue. A transmitter converts the transmission data packet format and transmits the data to the shared medium.

Method and apparatus for distributed optimal reverse link scheduling of resources, such as rate and power, in a wireless communication system

Abstract: A method, and corresponding apparatus, applies to individual base stations in a wireless communications systems, where each base station performs rate assignment to mobile stations optimally, but independently of the other base stations. Different base stations affect each other through other cell interference, and continuously modify their reversed link rate assignment based on the other-cell interference received and the requested rates from the mobile stations. The base stations converge to a stable condition with uncoordinated optimizations. The optimizing technique maximizes total through put in each cell (maximizing rates) while maintaining interference to other cells at a minimum level, and being subject to at least some of the following constraints: mobile station's maximum transmit power, mobile station's requested rate, discrete set of possible rates, maximum rise-over-thermal interference at the base station, and minimum required received error per bit normalized for noise.

Dual strip antenna with periodic mesh pattern

Abstract: A dual strip antenna that includes first and second conductive strips, each made from a conductive material. The first and second strips are separated by a dielectric substrate having a predetermined thickness. The first strip is electrically connected to the second strip at one end. A coaxial signal feed is coupled to the dual strip antenna. A dual strip antenna can be reduced in overall size by utilizing a periodic mesh patterned conductive surface in place of a solid continuous conductive surface. The periodic mesh pattern maintains the relative voltage and current relationships across the antenna strip while enabling a reduction in physical size. Any uniform periodic mesh pattern may be used and the periodic mesh pattern may be utilized for both strip elements. A brick-wall mesh pattern results in approximately 10% reduction in size over a solid continuous dual strip antenna.

Method and apparatus for signal processing in a satellite positioning system

Abstract: A method and apparatus for processing satellite positioning system (SPS) signals which are weak in level. In one embodiment, a SPS receiver receives at least two signal samples representing, at least in part, common information, wherein the two signal samples are associated with one or more satellite messages. By combining the two signal samples, navigational information (e.g., time, position, velocity, etc.) may be determined based on the combination of the two signal samples. According to another embodiment, the two signal samples are differentially demodulated and summed together to form the combination.

Effect of out-of-band terminations on intermodulation distortion in common-emitter circuits

Abstract: This paper presents the results of Volterra series analysis of the third-order intermodulation distortion in common-emitter circuits. The derived closed-form expression shows how out-of-band source and load impedances affect the distortion. The expression was used to optimally tune the input matching network of a 2 GHz Si BJT LNA at the sub- and second-harmonic frequencies for a higher IIP/sub 3/. While the in-band noise figure, gain and input return loss were not affected, the peak IIP/sub 3/ increased by 14 dB.

Position location with low tolerance oscillator

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the correction signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.

Method and apparatus for transmitting and receiving variable rate data

Abstract: A method for transmitting and receiving variable rate data. The data is spread using a long pseudo noise code generated by a linear feedback PN generator (16), the mask of which is selected by mask selector (14) in accordance with the transmission rate of the variable data and the specific user transmitting the data. Thus, by identifying at the receiver which mask will allow the received waveform to be correctly despread, the rate of the data can be determined.

Forward and reverse link power control using position and mobility information

Abstract: A method and apparatus for dynamically adjusting a power control loop that attempts to maintain either the transmit power of a signal sent from a base station to a mobile station or the signal to noise ratio of a signal sent from the mobile station (300) to the base station (400) above a minimum threshold and below a maximum threshold. Location information that is representative of the distance and morphology between the mobile station (300) and the base station (400) and the velocity of the mobile station (300) are determined. The minimum and the maximum thresholds of the power control loop are then adjusted in accordance with the location and the mobility information such that the minimum and the maximum threshold vary as the distance and the morphology between the mobile station (300) and the base station (400) and the velocity of the mobile station (300) change. In addition, the step size used to increase or decrease the transmit signal power, is adjusted in accordance with the velocity of the mobile station (300). A transmitter sends the signal at a power level that is controlled by the power control loop with the adjusted minimum threshold.

Cdma transmission of packet-switched data

Abstract: A method for conveying packet data from a CDMA mobile station (40) to a GSM network (22), including communicating with a GSM service node to establish a data link from the mobile station (40) to the network (22) via a radio communications base station (32). The packet data are conveyed between the mobile station (40) and the base station (32) over a CDMA air interface and are then transferred over the link between the base station (32) and the network (22).

Multi-loop SIGMA DELTA analog to digital converter

Abstract: A bandpass SIGMA DELTA DC utilizing either a single-loop or a MASH architecture wherein the resonators are implemented as either a delay cell resonator, a delay cell based resonator, a Forward-Euler resonator, or a two-path interleaved resonator. The resonator can be synthesized with analog circuit techniques such as active-RC, gm-C, MOSFET-C, switched capacitor, or switched current. The switched capacitor or switched current circuits can be designed using single-sampling, double-sampling, or multi-sampling circuits. The non-stringent requirement of a SIGMA DELTA ADC using switched capacitor circuits allows the ADC to be implemented in a CMOS process to minimize cost and reduce power consumption. Double-sampling circuits provide improved matching and improved tolerance to sampling clock jitter. In particular, a bandpass MASH 4-4 SIGMA DELTA ADC provides a simulated signal-to-noise ratio of 85 dB at an oversampling ratio of 32 for a CDMA application. The bandpass SIGMA DELTA ADC can also be used in conjunction with undersampling to provide a frequency downconversion.

Reduced complexity decision feedback equalization for multipath channels with large delay spreads

Abstract: Two modified decision feedback equalization (DFE) structures are presented for the efficient equalization of long sparse channels with strong precursor, such as those encountered in high-speed communications over multipath channels with large delay spread. Unlike the conventional DFE, these structures allow the channel's sparseness to be exploited by simple tap allocation, before the sparseness is degraded by feedforward filtering. Both structures yield large reductions in complexity while maintaining performance comparable to the conventional DPE, hence overcoming a key computational bottleneck when equalizers are implemented in hardware for speed. Fast channel estimate-based algorithms for computing the modified DFE coefficients are derived. Simulation results are presented for data rates and channel profiles of the type considered for the proposed North American high definition television (HDTV) terrestrial broadcast mode.

Method and apparatus for paging a user terminal within the “sweet spot” of a satellite

Abstract: An apparatus and method for paging a user terminal (UT) using a satellite communications system having a gateway and one or more satellites, wherein each satellite produces a plurality of beams and each beam includes a plurality of channels. The method of the present invention includes the step of recalling a location of the UT, wherein the recalled location corresponds to a location of the UT at a time t1. In one embodiment this is accomplished by performing a lookup in a table that includes location information for user terminals at different points in time. The method also includes the step of determining an area, based on the recalled location, within which the UT is assumed to be located at a time t2, where time t2 is later in time than time t1. The next step is to determine a time t3, where t3 is equal to or later in time than time t2, when the following two criteria are satisfied. First a satellite of the one or more satellites has an elevation angle between θ1 and θ2. Second, all locations within the area are located within a footprint of the satellite (that has an elevation angle between θ1 and θ2). The elevation angles θ1 and θ2 can be determined from the perspective of the recalled location. Alternatively, the elevation angle can be determined from the perspective of all locations within the area. This ensures that the UT is in the “sweet spot” of the satellite (where the gain of signals sent from the satellite are highest) when the UT is paged. A page is then sent from the gateway to the UT on a channel of a beam of the satellite at time t3. The page can be sent on a channel of every beam of a plurality of beams that make up the footprint of the satellite at time t3. Alternatively, the page can be sent on a channel of selected beams of the footprint. By waiting until the UT is within the “sweet spot” to page the UT, less power can be used by the satellite. In addition, this type of operation allows the UT to use an antenna that has a substantial gain only when the UT is within the “sweet spot”. This allows the use of satellite power to be reduced further.

Clients remote access to enterprise networks employing enterprise gateway servers in a centralized data center converting plurality of data requests for messaging and collaboration into a single request

Abstract: A computer system includes an enterprise gateway server and a remote gateway server connected via a data network, such as the Internet, that is relatively inefficient compared to typical private networks. The remote gateway server interfaces the enterprise gateway server to corporate messaging and collaboration data stored locally relative to the remote gateway server. The enterprise gateway server converts multiple data requests for the messaging and collaboration data into a single higher-level data request that is transmitted across the data network. The remote gateway server receives the request and converts the single high level request back into the original multiple request format for presentation to the messaging and collaboration database.

Amplifier with adjustable bias current

Abstract: An amplifier (1220, 1220a, 12206) having an adjustable current source (1580) which can be controlled to provide the requisite level of performance at reduced current consumption. The amplifier is first designed using one of many designs available and known in the art. A current source is then designed to provide adjustable bias current for the amplifier. The current source (1580) can be designed with MOSFETs (1582, 1584) which require no additional bias current and can accept a standard digital control signal. The current source (1580) can also be designed with active devices which are selected based on the logic of the control signals for ease of interface. The bias current determines the linearity and noise performance of the amplifier. The bias current is adjusted to provide the requisite level of performance while reducing power consumption. The current source can be designed to operate in discrete steps or to have substantially continuous current steps.

A method and apparatus for maximizing standby time using a quick paging channel

Abstract: A quick paging system having a base station (12), a plurality of terminals (10), and a full paging channel having a plurality of slots (32) for transmitting paging information to the terminals (10). A quick paging channel having a plurality of quick paging channel slots (30) each corresponding to a full paging channel slot (32) is provided wherein at least one indicator (102, 104) is positioned within a selected quick paging channel slot (30) that instructs at least one selected terminal (10) corresponding to the at least one indicator (102, 104) in the quick paging slot (30) to monitor the corresponding full paging channel slot (32).

Method and apparatus for controlling transmission power in a potentially transmission gated or capped communication system

Abstract: A power control system for controlling the transmission power in a system wherein the transmission power may be gated or capped. The receiver employs a combination of closed loop and outer loop power control. The outer loop is frozen upon detection by the receiver that the signal has been capped or gated.

Methods and apparatuses for fast power control of signals transmitted on a multiple access channel

Abstract: A method and apparatus for controlling the transmission of signals from one or more of a plurality of mobile stations (1300) to a base station (1400) on a plurality of M multiple access channels. A power control information packet formed from a plurality of power control bits is transmitted from the base station (1400) to the one or more mobile stations (1300). Each of the power control bits in the power control information packet has a position that is mapped to a selected access channel and to a time offset within the selected access channel. The power control information packet is received at a first mobile station (1300). A message is then transmitted from the first mobile station (1300) to the base station (1400) on a first access channel and at a first time offset associated with the first access channel. The message is transmitted from the first mobile station (1300) at a power level determined in response to a first power control bit in the power control information packet. The first power control bit is located in a first position in the power control information packet, the first position being mapped to the first access channel and the first time offset.