Bell Communications Research, Inc.

At&t Bell Laboratories

Telcordia Technologies, Inc.

Hamilton W Arnold

Nelson Ray Sollenberger

Sirikiat Lek Ariyavisitakul

Larrie G Sutliff

Vijay K Varma

Daniel M Devasirvathan

Ravi Kumar Jain

Li Fung Chang

Robert A Ziegler

Anthony Robert Noerpel

Li-Fung Chang

Joseph Frank Rizzo

Robert Conrad Malkemes

Kenneth White Leland

Daniel M Devasirvatham

Scott Yates Seidel

A mobile system capable of proactively predicting characteristics for optimal communication among mobile nodes comprises a network controller and adaptive predictive mobile nodes. The adaptive predictive mobile nodes contain a position location technology element, a database containing information on factors affecting radio propagation, and a prediction processor. To provide energy efficient power control and routing for a communication, the adaptive predictive mobile node determines its current and predicted future position and the current and future predicted positions of other nodes in the network. Based on the information obtained, the adaptive predictive node executes a set of prediction capabilities in the prediction processor. After executing these capabilities, the adaptive predictive node identifies the advantaged location, power level, transmission parameters, communication time and route for communications between nodes. The adaptive predictive mobile node can then communicate when the criteria are met or may request scheduling for the communication based on the criteria. To request scheduling, the adaptive predictive node communicates the identified criteria to the network control entity. The network control entity determines whether the request can be supported. If the network can support the request, the communication is scheduled. If the network cannot support the request, the adaptive predictive node has the option of recalculating the criteria for communication and requesting scheduling based on the alternative criteria.

System and method for energy-efficient transmission power control, routing and transmission scheduling in wireless communication networks

Disclosed are a system and method for providing wireless access to a network, such as the internet. The disclosed technique takes into account the inherent asymmetric and bursty characteristics of internet communication to obtain more efficiency in the communication between a user and an access provider. In doing so, the invention provides a technique that can be used to economically provide wireless access to the internet at data rates that are comparable to what a user would receive over ISDN lines.

Method and system for wireless internet access

An apparatus and method for reducing interference between an uplink transmitter of a space-based wireless communication system and an uplink or downlink receiver of a terrestrial wireless communication system are described. The space-based system may be a Fixed Satellite Service (FSS) system and the terrestrial system may be a Local Multipoint Distribution Service (LMDS) system. An ordered list of preferred uplink transmission frequencies is assigned to all FSS uplinks located in a particular cell of the LMDS system. Different ordered lists are used in different cells of the LMDS system, while uplinks located in the same cell can utilize the same ordered list. A given potentially-interfering uplink transmitter selects an uplink transmission frequency from the appropriate ordered list if the uplink is unable to operate outside the LMDS frequency band and there are no gaps in the LMDS spectrum which can accommodate the uplink transmission. The ordered list may be selected by the LMDS service provider such that the impact of interference from FSS uplinks can be readily predicted and minimized. The invention thus allows simultaneous access to a shared frequency band for both LMDS and FSS systems.

Interference reduction in shared-frequency wireless communication systems

In a TDM/TDMA portable radio communications system, a portable handset is compatible for operation in both a frequency-division duplexing (FDD) mode for communication in the licensed portion of the Emerging Technologies frequency band, and in a time-division duplexing (TDD) mode for communication in the unlicensed portion of the Emerging Technologies frequency band. In the FDD mode, different frequencies are used to separate a downlink transmission to a portable from a port from an uplink transmission from a port to a portable. In the TDD mode, uplink and downlink transmissions are separated in different time-slots, but at the same frequency. The handset includes common transmit and receive circuitry that operates at fixed IF frequencies that are separated in frequency by the fixed FDD frequency difference between corresponding uplink and downlink signals. In the FDD mode, therefore, a frequency synthesizer (301), which is used to tune to transmit and receive at different frequencies from different ports, does not have to switch its frequency between transmitting and receiving a burst to and from a single port. In the TDD mode, however, even though uplink and downlink signals are at the same frequency, the synthesizer is switched in frequency between transmitting uplink and receiving downlink.

Compatible licensed and unlicensed band portable handset unit for TDMA

A system for spectrum sharing between a point-to-point microwave system and a TDM/TDMA wireless communications system in a common geographical area is described. Each transmitter/receiver in the point-to-point microwave system transmits, in addition to its normal information signal, a beacon signal which is uniquely associated with the receiver receive frequency. In selecting uplink and downlink frequencies for port assignment, each port monitors the beacon frequencies and selects as uplink and downlink frequencies, frequencies which associated beacons fall below a predetermined threshold. Similarly, before accessing the wireless communications system through a selected port, a portable monitors the beacons associated with the selected port's uplink frequency. If the beacon associated with the uplink frequency exceeds a threshold, the portable selects an alternate port through which to access the network. Also, during a call an emergency link transfer to another port is made if the monitored beacon corresponding to the portable's uplink frequency rises above the threshold.

Beacon detection method and apparatus for sharing spectrum between

Beacon detection system for sharing spectrum between wireless

A receiver for use in the port or portable units in a TDM/TDMA digital radio communications system is disclosed which incorporates an equalizer (107) to compensate for channel distortion due to multipath delay spread. Each received burst of information is oversampled at a multiple of the symbol rate and stored in a buffer memory (105). A joint estimator (106) processes the stored burst by operating on a known training sequence of bits within the burst to determine burst timing (where the burst actually begins) and the symbol timing (the optimum sample sample per oversampled symbol to be used for detection purposes). The estimator also determines whether the stored burst should be processed in a time-forward or time-reversed order. The joint estimator includes plural training equalizers (201), each of which is associated with an assumed burst location and each of which attempts to converge on the known training sequence as the stored sequence is circulated plural times through the equalizers in both the time-forward and time-reversed order. Burst and symbol timing and the optimum processing order are determined from the location of the training equalizer which converges with the minimum mean-square error. The determined burst and symbol timing, and the selected processing order, are passed to the buffer storage for read-out, in that selected order, of the stored burst information in that order to the input of the main receiver equalizer (107). That main equalizer is initially set with the equalizer parameters determined by the training equalizer yielding the minimum mean-square error. The equalizers can either be conventional fractionally-spaced decision feedback equalizers or can be phase equalizers, which operate on the received phase angle.

Phase equalizer for TDMA portable radio systems

Digital circuitry comprising multiple read-only-memory (ROM) units that store predetermined data sequences are utilized to generate a digital representation of a composite signal that represents overlapping Nyquist pulses derived from input data bits. The generated signal exhibits relatively fast ON/OFF transitions. At the same time, control signals applied to the outputs of the ROMs insure that the representation preserves prespecified tail portions that minimize spectral spreading in a time-division multiple-access (TDMA) system. Once version of the circuitry generates a digital representation of a baseband signal derived from a single stream of input data bits. Another version of the circuitry generates a digital representation of a quadrature-phase-modulated carrier derived from two independent input data streams.

Digital circuits for generating signal sequences for linear TDMA systems

A receiver for use in the port or portable units in a TDM/TDMA digital radio communications system is disclosed which incorporates an equalizer (107) to compensate for channel distortion due to multipath delay spread. Each received burst of information is oversampled at a multiple of the symbol rate and stored in a buffer memory (105). A joint estimator (106) processes the stored burst by operating on a known training sequence of bits within the burst to determine burst timing (where the burst actually begins) and the symbol timing (the optimum sample per oversampled symbol to be used for detection purposes). The estimator also determines whether the stored burst should be processed in a time-forward or time-reversed order. The joint estimator includes plural training equalizers (201), each of which is associated with an assumed burst location and each of which attempts to converge on the known training sequence as the stored sequence is circulated plural times through the equalizers in both the time-forward and the time-reversed order. Burst and symbol timing and the optimum processing order are determined from the location of the training equalizer which converges with the minimum mean-square error. The determined burst and symbol timing, and the selected processing order, are passed to the buffer storage for read-out, in that selected direction, of the stored burst information to the input of the main receiver equalizer (107). The main and training equalizers can be either conventional fractionally-spaced decision feedback equalizers or phase equalizers, which operate on the received phase angle.

Time dispersion equalizer receiver with a time-reversal structure for

In order to correctly demodulate a received sequential burst of symbols in a Time Division Multiple Access (TDMA) radio system, proper symbol timing is necessary. A method and circuitry for estimating symbol timing is disclosed in which the IF radio signal is sampled and digitized at a sampling rate which is sixteen times the symbol rate. The digitized samples are processed to obtain phase values. A one symbol delay is introduced and differential phase values derived, a differential phase value being derived for each of the sixteen sampling times per symbol. The differential phase values are compared with expected differential phase values and the absolute differences are accumulated for each sampling time over substantially the entire burst. The symbol timing is selected to be the particular one-of-the-sixteen sampling times that results in the minimum sum of differences.

Method and circuitry for determining symbol timing for time division

The present invention relates to a transmitter and a receiver for use in a digital communication system which are capable of transmitting and receiving, respectively, a single duplex analog signal channel, such as, for example, a voice channel, and limited short asynchronous data bursts. The transmitter portion includes an encoding means which uses an adaptive companding algorithm in the encoding process while the receiver portion includes a decoding means using the same synchronized algorithm in the decoding process. The transmitter and receiver at each end of a communication channel also include a signaling interface which can interrupt the coding and decoding process to transmit and receive, respectively, an occasional data burst without upsetting the synchronization of the adaptive companding algorithm states at both ends of the channel.

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Neptune, NJ, United States of America

Hamilton W Arnold