Abstract: A apparatus linearizing and technique for linearizing a non-linear power amplifier used in a transmitter of, e.g., a TDMA mobile wireless telephone. Linearization of the non-linear amplifier by changing the shape of the input signal is performed when the input signal level is high, thus increasing efficiency or reducing power consumption at that time, albeit at the cost of increased inter-symbol interference (ISI). However, since the input signals at that time are at a high level, the increased ISI can be tolerated and adjacent symbols can still be distinguished from one another. The invention allows use of a non-linear power amplifier which typically enjoys a lower current consumption than that of a linear power amplifier, thus increasing the time between battery recharges and/or reducing the overall size of the wireless telephone device. The power amplifier is operated in a linear mode when transmitted power is low, thus allowing differentiation between adjacent symbols (i.e., improvement of ISI).
Abstract: A method and system for autonomous two-way RF communication between a launch vehicle and at least one receiving or tracking station. Detection circuitry continuously determines the identity of the optimum receiving or tracking station (ground, sea, airborne, or satellite) and selects the best launch vehicle transmission antenna to close the RF telemetry link. The method and system is designed to simultaneously transmit and receive RF signals. The antenna system includes a telemetry transmission link and an antenna selection link. Antenna selection link signals received by each antenna element on the launch vehicle are provided via RF couplers to a receiver for signal strength and modulation signal detection. The telemetry transmission link communicates with a receiving or tracking station by using a transmitter to drive one of two or more switched antennas mounted on the surface of the launch vehicle having the current higher signal strength.
Abstract: A power control system for a multi-carrier base station transmitter is capable of controlling power levels of individual RF carriers. The power control system has a multi-channel conversion system for generating a plurality of analog reference signals corresponding to a plurality of digital input signals. The multi-channel conversion system also generates an analog multi-carrier signal and samples the multi-carrier signal. The multi-carrier signal represents a summed amplification of the digital input signals. A correlating power detection system is connected to the multi-channel conversion system and generates digital total power control signals based on the analog reference signals and the analog sampled multi-carrier signal. A feedback conversion module is connected to the multi-channel conversion system and the correlating power detection system and individually controls amplification of the digital input signals based on the total power control signals.
June 28, 2000
Date of Patent:
March 18, 2003
Mark Kintis, Donald R. Martin, Vincent C. Moretti
Abstract: A method is disclosed for increasing signaling link capacity between nodes in a digital cellular communications system, wherein the signaling message to be conveyed over the link is compressed. The compressed message received at the other side of the link is then decompressed. As a consequence, the capacity of the signaling links between nodes can be increased up to 100%, and mobile station registration restrictions can be reduced. The method is disclosed for compressing MTP messages, but it can also be used for compressing other signaling messages to improve link capacity.
Abstract: A method and apparatus for maintaining a record of radio signal strength for a plurality of channels in a wireless communication system is provided. A detector detects radio signal strength on each channel, and a memory stores information relating to the detected signal strengths. The information is stored in the form of a value for each channel. Each value is stored in an array and values are stored in the array such that each position in the array is assigned to a particular channel. The use of an array allows stored values to be associated with respective channels by the position that the value is held in.
Abstract: An open/close-type telephone with a speech recognizer allowing ease of use and security to be improved is disclosed. The speech recognizer is activated when the telephone is opened and, when predetermined speech is inputted the dialing-inhibition state is canceled to allow dialing.
Abstract: A device and method for tracking the location of a mobile telephone in multipath fading and a non-line-of-sight environment. In the device for tracking the location of a mobile telephone, each of a plurality of base stations receives a predetermined signal from the mobile telephone and calculates the distance between the mobile telephone and the base station based on the time of arrival of the signal at the base station. A location data processor receives information about the distances from the base stations, draws circles with the radii being the distances and the coordinates of the base stations at the centers thereof around the base stations, and determines the location of the mobile telephone using location tracking curves connecting the intersection points of the circles.
Abstract: An up-converter section and a down-converter section are contained in separate respective chassis. The up-converter section and the down-converter section are linked by an IF link section having a coaxial shielding structure. As such, a high-quality Up/Down tuner can be provided which is able to reduce the mutual influence of up-converter and down-converter local oscillator circuits and the entry of external noise, without increasing the size of the Up/Down tuner.
Abstract: An audio coupling is provided between a location reporting unit and the microphone of a wireless phone in which location information is provided either by synthesized voice and/or DTMF tones through the audio coupling to the microphone such that the location of the wireless phone can be broadcast on the normal voice channel to a dispatch operation such as a Public Safety Answering Point or to a location-based service provider. The subject interface makes possible the adaptation of any wireless phone to provide location-based information without change to the wireless phone and without any additional infrastructure for the wireless network. The utilization of synthesized speech and/or DTMF tones over the voice channel provides a universality for the system, which can be utilized anywhere where there is both wireless and GPS satellite coverage.
Abstract: A communications terminal, such as a wireless mobile terminal, is supplied with an indication of group call characteristics for incoming group calls so as to distinguish such calls from other types of incoming calls. A Group Call Server in charge of the group call may selectively augment the calling party number field of the paging message with one or more indicator “flag characters,” indicating one or more characteristics of the group call, such as call type, call subtype, or priority level. The communications terminal receives the group call paging message and selects the appropriate response to the paging message based on the flag characters. The communications terminal preferably examines the calling party field of the paging message and notes the presence of the flag characters. When the flag characters are present, the communications terminal parses out the flag characters and calling party ID.
Abstract: To address problems associated with interference in a received signal of a direct conversion receiver within a transceiver, an error estimator is employed to reduce errors induced on the baseband of the received signal. Knowledge that the transmitter within the transceiver is the strongest interferer can be used by the error estimator to subtract the interference caused by transmitter from the received signal. Additionally, this can be achieved even though the interference on the I and Q channels of the receiver is not equal.
Abstract: In the field of mobile radio telephony, a method and system are provided for sending general information messages to users in a mobile radio network on a geographical selective basis. A mobile station is the mobile radio network is capable of sending location update messages to the mobile radio network. These location update messages include information of the location of the mobile station. The general information message to be sent is registered in the network, together with an identification of a served geographical area to which the general information message is relevant. When a location update message is received from a mobile station located within this served geographical area, the general information message is sent to this mobile station.
March 5, 1999
Date of Patent:
January 21, 2003
Telefonaktiebolaget LM Ericsson (publ)
Markus Stocker, Carmine Russo, Martin Dätwyler
Abstract: A system adjusts a receiving device in response to sensing symbols. An automatic gain control is adjusted in response receiving a first symbol of a data unit from a first antenna. After adjusting the automatic gain control at least a second and a third symbol of the data unit are received, and in response thereto (1) a first energy of at least one of the second and third symbols is calculated, (2) a first frequency offset of at least one of the second and third symbols is calculated, and (3) a first temporal offset of at least one of the second and third symbols is calculated. The automatic gain control in response receiving a fourth symbol of the data unit from a second antenna is received.
Abstract: A method for configuring access points of a network providing wireless communications coverage for an environment, including determining a coverage radius of an access point at certain locations within the environment, determining an average coverage radius of the access points for the environment based on the determined coverage radii, positioning the access points at locations within the indoor environment to provide continuous radio coverage for the environment based on the average coverage radii, assigning a weight indicative of overlapping coverage for each pair of access points having overlapping coverage, and assigning a channel to each of the access points based on certain sums of the weights to minimize coverage overlap between access points operating at the same channel.
Abstract: Method and an apparatus for determining the pathloss between a base transceiver station (BTS) and a mobile station (MS) in a mobile radio network. In detail, a signal carrier (BCCH) having a transmitting power (PTXAV) is transmitted by a first base transceiver station (BTS-1). Thereafter, said signal carrier (BCCH) transmitted by said first base transceiver station (BTS-1) is received by a mobile station (MS) spatially separated from said first base transceiver station (BTS-1), and the signal level (PTXAV) of the received signal carrier (BCCH) is detected by said mobile station (MS). Furthermore, the detected signal level (PTXAV) of said received signal carrier (BCCH) is transmitted to a second base transceiver station (BTS-2) of a neighboring cell. In addition, the detected signal level (PTXAV) of said signal carrier (BCCH) received by said mobile station (MS) is compared with the transmitting power (PTXAV) of said signal carrier (BCCH) transmitted by said first base transceiver station (BTS-1).
Abstract: A method facilitates provisioning of pre-paid wireless services. Credit refresh operations involving a pre-paid wireless communication device involve SMS messages transmitted to the device over-the-air. The device uses tariff tables to keep track of a calls impact on available credit. The tariff tables are updatable at the service provider's discretion using SMS messages.
July 16, 1999
Date of Patent:
November 12, 2002
Bernard Thomas Laybourn, Theodore W. Watler
Abstract: An upconverter unit for a cable television system upconverts multiple channel signals from a common intermediate frequency to a VHF or UHF signal ready for transmission to subscribers. The two-stage upconverter provides a first stage in which different channel signals are upconverted to different frequencies which are spaced apart by same frequency difference characteristic of different channels in the cable system. A second stage of the upconverter uses a common oscillator signal to convert the various channel signals from the first stage to the frequencies at which they will be transmitted over the cable system.
Abstract: A system for synchronizing a second receive chain relative to a first receive chain in a multi-mode communication system. The system includes a first circuit that measures a first frequency associated with the first receive chain. A second circuit adjusts a second frequency associated with the second receive chain based on the first frequency and provides a desired second frequency to the second receive chain in response thereto. In a specific embodiment, the first circuit includes a first counter that receives a signal associated with an output of a first oscillator and provides a measurement of the first frequency in response thereto. The second circuit includes a frequency synthesizer for providing the desired second frequency in response to a frequency control or reference signal. Another circuit generates the control or reference signal based on a difference between the second frequency and the first frequency.
Abstract: The penalties associated with relying on layer-4 to handle packets lost as a result of a handoff can be reduced by forwarding, in response to a handoff request from a first base station to a second base station, at least one layer-2 frame of a layer-3 packet destined to/from the wireless terminal that has been passed down from layer-3 to layer-2, and so is indicated to have been transmitted at layer-3 even though not all of the layer-2 frames of the layer-3 packet have actually been transmitted. In one embodiment of the invention, each of the at least one layer-2 frames may be encapsulated together in a special layer-3 packet that is transferred from the first base to the second base station in the usual manner of inter-base-station communication. Advantageously, packets are not lost at layer-4 due to handoffs. Thus, layer-4 retransmissions are not required, and so delays in the network are reduced.
February 9, 2000
Date of Patent:
October 8, 2002
Lucent Technologies Inc.
Stephen William Davies, Michaela C Vanderveen
Abstract: A high frequency power amplifying apparatus is provided with an amplifying section with a plurality of amplifying stages connected in cascade. A power control signal is supplied to the amplifying section through a control terminal so as to control the output of the high frequency power amplifying apparatus. Each of the amplifying stages has a gain smaller than that of a preceding stage. Gain control signals generated from the power control signal are supplied to the respective amplifying stages. Dividing resistors are connected in series with one another between the control terminal and a reference potential so as to divide the voltage of the power control signal to thereby generate a plurality of different gain control signals. Different ones of the gain control signals are supplied to the respective amplifying stages, an absolute value of a voltage of the gain control signal applied to each stage is larger than that applied to an earlier preceding stage.