At+t Corp.

Bell Communications Research, Inc.

At&t Intellectual Property I, LP

Justin C Chuang

Nelson Ray Sollenberger

Jack Winters

Ye Li

Lang Lin

Li Fung Chang

Xiaoxin Qiu

Kapil K Chawla

Sirikiat Lek Ariyavisitakul

Zoran Kostic

A method for establishing wireless communication between a transmitter and a receiver in a wireless communication system is disclosed. The receiver includes an adaptive array that has at least two antennas. Each antenna receives a signal and produces a received signal. The transmitter includes at least two transmission channels for communicating the signal from the transmitter to the receiver. The wireless communication system suppresses interference at the receiver by applying an interference suppression technique when combining the received signals. The selection of a channel at the transmitter is based on the channel performance at the receiver for each transmission channel. The channel performance is based on a combining technique different from the interference suppression technique.

System and method for selecting a transmission channel in a wireless communication system that includes an adaptive antenna array

System and method for selecting a transmission channel in a wireless communication system that includes an adaptive array

A method for decoding a received signal comprising the steps of receiving a signal at a plurality of antennas, applying Fast Fourier transformations to the received signal, estimating channel characteristics of a channel over which the signal was transmitted using iterative processing and decoding the transformed signal.

Near optimal joint channel estimation and data detection for COFDM systems

Joint channel estimation and maximum likelihood decoding method for Coded Orthogonal Frequency Division Multiplexing (COFDM) systems are presented. Using this method in conjunction with convolutional coding, robust and nearly optimal coherent detection can be achieved in rapid dispersive fading channels. Significant performance gain in packet data throughput is realized in a system with aggressive frequency reuse. A method for estimating channel characteristics in a multicarrier transmission system comprising the steps of receiving a multicarrier signal, applying Fast Fourier transformations to the multicarrier signal, estimating channel characteristics of a multicarrier channel over which the multicarrier signal was transmitted using a combination of iterative processing and iterative backward processing, and decoding the transformed multicarrier signal is presented.

Method for near optimal joint channel estimation and data detection for COFDM systems

A method for establishing wireless communication between a transmitter and a receiver in a wireless communication system. The receiver includes an adaptive array that has at least two antennas. Each antenna receives a signal and produces a received signal. The transmitter includes at least two transmission channels for communicating the signal from the transmitter to the receiver. The wireless communication system suppresses interference at the receiver by applying an interference suppression technique when combining the received signals. The selection of a channel at the transmitter is based on the channel performance at the receiver for each transmission channel. The channel performance is based on a combining technique different from the interference suppression technique.

Joint channel estimation and maximum likelihood decoding method for Coded Orthogonal Frequency Division Multiplexing (COFDM) systems are presented. Using this method in conjunction with convolutional coding, robust and nearly optimal coherent detection can be achieved in rapid dispersive fading channels. Significant performance gain in packet data throughput is realized in a system with aggressive frequency reuse. A method for estimating channel characteristics in a multicarrier transmission system comprising the steps of receiving a multicarrier signal, applying Fast Fourier transformations to the multicarrier signal, estimating channel characteristics of a multicarrier channel over which the multicarrier signal was transmitted using a combination of iterative forward processing and iterative backward processing, and decoding the transformed multicarrier signal is presented.

An arrangement where, in addition to the control channels that are used to set up sessions, there is a logically and physically separate and independent set of control channels that can be used as session control channels. Illustratively, the physical GSM frame arrangement that employs 8 logical slots is used, with one slot both in the uplink and downlink dedicated to these separate control channels. In the downlink, such a control channel provides channel grant information, requests to make and transmit power measurements, poll mobile units, etc. In the uplink, such a control channel can be used to request access to a traffic channel, to report on power measurements, to request special hand-off handling, to respond to polling, etc. Because the uplink session control channel does not need to carry a significant amount of information, the GSM slot can be divided into minislots, with each minislot constituting a session control channel for a group of mobile units.

Medium access control layer for packetized wireless systems

This invention provides a dynamic frequency hopping system that utilizes information from multiple base stations. The system assigns frequency hopping patterns based on current interference and traffic environments to avoid interference thus gaining the benefits of interference averaging and interference avoidance. The system imposes less stringent measurement requirements on terminals (wireless mobile devices) because many measurement requirements are replaced by generating estimates based on measurement data received from other base stations within a base station neighborhood. The system may continuously verify that the frequency hopping patterns assigned to the links of the system optimizes system performance. The system compares system performance of possible frequency hopping patterns against currently assigned frequency hopping pattern to optimize system performance. When a request for a link is received, a similar process as above is performed where the request is granted/denied/delayed based on system optimization requirements. In this way, the frequency hopping patterns of the links of the system may be assigned so that an optimum system performance may be obtained.

Dynamic frequency hopping

Joint channel estimation and maximum likelihood decoding method for Coded Orthogonal Frequency Division Multiplexing (COFDM) systems are presented. Using this method in conjunction with convolutional coding, robust and nearly optimal coherent detection can be achieved in rapid dispersive fading channels. Significant performance gain in packet data throughput is realized in a system with aggressive frequency reuse. A system for estimating channel characteristics in a multicarrier transmission system comprising means for receiving a multicarrier signal, means for applying Fast Fourier transformations to the multicarrier signal, means for estimating channel characteristics of a multicarrier channel over which the multicarrier signal was transmitted using iterative processing and means for decoding the transformed multicarrier signal is presented.

System for near optimal joint channel estimation and data detection for COFDM systems

A method and system for controlling media access in which a paging message is transmitted from a base station to a wireless station when a data packet is received for downlink transmission to the wireless station. The base station is one of a plurality of base stations and the wireless station is associated with the base station. In response to the paging message, a level of each of a plurality of pilot frequency signals is detected at the wireless station. Each pilot frequency corresponds to a downlink traffic channel and is transmitted by base stations to which the downlink traffic channel is assigned. The wireless station generates a list of preferred traffic channels based on a priority order of traffic channels and on detected levels of the pilot frequency signals, and transmits the list to the associated base station. A downlink traffic channel is assigned for downlink transmitting the received data packet to the wireless station based on the list of preferred traffic channels and updates a channel priority order list at the base station.

System and method for dynamically assigning channels for wireless packet

In a TDM/TDMA digital radio communications system, time synchronization between fixed ports is achieved by adjusting the timing of a first port in response to the average timing difference between the timing of that first port and the timing measured by that first port of the downlink signals transmitted by a fixed number of the other ports in the system, which downlink signals are detected at the first port and determined to have the highest signal quality measures. Each of the other ports in the system sequentially performs the same process and the entire process is then reiterated a plurality of times at all of the ports until timing of the system converges.

Method and apparatus for synchronizing timing among radio ports in

In a TDM/TDMA digital radio communications system a few selected ports are connected to a fixed common timing reference and designated as master ports. Each master port is assigned a hierarchical value of zero. Every other port is initialized a high hierarchical value before performing an autonomous iterative procedure to synchronize timing to its nearest master port. By demodulating downlink signals transmitted from other ports when its own transmitter is turned off, a receiving port selects only a fixed number of ports providing the best signal quality with respect to which to adjust its timing. The relative timings and the hierarchical values of the transmitting ports are compared with those of the receiving port. If the hierarchical value of the receiving port, H.sub.R, is greater than or equal to the lowest hierarchical value, H.sub.L, of the transmitting ports, it adjusts its timing based on the timing differences with respect to the set of ports having a hierarchical value of H.sub.L and which have the highest signal quality. Further, H.sub.R is set to H.sub.L +1 if H.sub.R is greater than H.sub.L. The master timing propagates rapidly in a hierarchical way, which results in time synchronization of the entire system without timing drift.

In a TDM/TDMA portable radio communications system the uplink power transmitted by the transmitter of a portable unit to a fixed port is dynamically controlled by monitoring three measures in each uplink burst received by the port. These measures are a received signal strength indicator (RSSI), a quality measure (QM), and a word error indicator (WEI). The WEI is used to adjust an RSSI threshold upward and downward. If the QM is below a predetermined QM threshold or the RSSI is below the current value of the adjustable RSSI threshold, then additional uplink power is required, unless the RSSI is greater than a predetermined maximum RSSI value. If additional power is required a power control bit (PC), included within each downlink burst transmitted to the portable, is set to ONE and the portable, in response thereto, increases its output transmitter power. If both the QM is greater than the predetermined QM threshold and the RSSI is greater than the RSSI threshold, or if the RSSI is greater than the predetermined maximum RSSI value, then PC is set to ZERO and the portable transmitter power is decreased.

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Holmdel, NJ, United States of America

Justin C Chuang