Agere Systems Inc.

Ncr Corporation

Lucent Technologies Inc.

Greenpeak Technologies B.v.

Greenpeak Technologies N.v.

Adriaan Kamerman

Hans Van Driest

Geert Arnout Awater

Hendrik Moelard

Hendrik Van Bokhorst

Leo Monteban

Wilhelmus Diepstraten

Anjur Sundaresan Krishnakumar

Jan Boer

Wilhelmus J Diepstraten

Allert Van Zelst

Tim Schenk

Rienk Mud

Johannes P Haagh

Xiao-Jiao Tao

Isabella Modonesi

D J Richard Van Nee

Robert John Kopmeiners

Kai Roland Kriedte

Loeke Brederveld

Didier J Van Nee

Gerritt Willem Hiddink

Cornelis Adrianus Marinus Steenbergen

Albert Eikelenboom

Stephan Johann Noel

Bart Magda Alex Jonkers

Bram Hugo Bert Van Den Bosch

Timothy N Doolittle

Wilhelmus Josephus Diepstraten

The invention relates to a communication device () comprising an antenna system () provided with at least one antenna () for receiving a radio signal and supplying a received radio signal to an output () of the antenna system, a low noise amplifier () for amplification of the received radio signal to obtain an amplified radio signal, and a processing unit () for processing the amplified radio signal. The antenna system () is configured to supply in a first state a first antenna signal as the received radio signal and in a second state second antenna signal as the received radio signal, wherein the first antenna signal and second antenna signal differ in amplitude. The antenna system is further configured to switch from state in response to a control signal () generated by the processing unit ().

Communication device

A communication protocol based on CSMA between a node, in particular an electronic label, and a network coordinator is disclosed. The node comprises:&#x2014;a transceiver provided for communication with a network coordinator, wherein the transceiver handles a transmission channel based on CSMA;&#x2014;a processing unit provided for processing data received via the transmission channel and displaying the data on a display unit. The electronic label is arranged to perform:&#x2014;sending recurrently a data request packet;&#x2014;going to a low power mode after sending the data request packet; and&#x2014;waking-up for receiving a data response packet a predefined time interval after beginning sending the data request packet. The network coordinator is arranged to transmit the data response packet the predefined time interval after receiving the beginning of the data request packet. The invention provides a protocol based on CSMA with very low power operation in which a multitude of end nodes could receive from a network coordinator their corresponding data.

End node and network coordinator using a CSMA based protocol

A communication system with a plurality of access points (AP, AP, AP) and at least one network station (), the network station () being arranged to communicate with one of said the plurality of access points (AP, AP, AP) through a wireless communication protocol, each access point (AP, AP, AP) is able to monitor its access point traffic load and transmit an access point traffic load parameter (ATT) to the network station (), and the network station () is able to monitor its network station traffic load; store a network station traffic load parameter (AUTT); receive access point traffic load parameters (ATT) from the access points (AP, AP, AP); and select a communication connection with one of the access points (AP, AP, AP) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Wireless LAN with load balancing

A method and apparatus are disclosed for automatic transmit power variation in a wireless communication system. A wireless communication device according to the present invention includes a dynamic transmit power controller that adapts a transmit power level based on a transmission rate of the data. One aspect of the dynamic transmit power controller selects a maximum allowable power level that is based on limits specified for a given region and frequency band, or a maximum directional gain of an antenna (or both). Another aspect of the dynamic transmit power controller selects a maximum capable power level that is based on the transmission rate, frequency band, or characteristics of a transmitter output amplifier (or a combination of the foregoing). Generally, the transmit power level is selected based on a minimum of the maximum allowable power level and the maximum capable power level.

Method and apparatus for automatic transmit power variation in a wireless communication system

In a multiple-input, multiple-output (MIMO) system, a receiver is implemented with at least one additional receive path beyond the number of transmit antennas used to transmit the signals (e.g., wireless OFDM signals) received at the receiver. In one embodiment, the additional receive path is used to reduced co-channel interference (CCI) in the recovered OFDM signals. In particular, each receive path applies recursive filtering to generate separate subcarrier signals. A processor converts the separate subcarrier signals from the different receive paths into a first set of subcarrier signals corresponding to each transmitted OFDM signal, where each first set of subcarrier signals has desired signal and possibly CCI. The processor also generates a second set of subcarrier signals corresponding to the CCI. The processor subtracts portions of the second set of subcarrier signals from each first set of subcarrier signals to generate recovered OFDM signals having reduced CCI.

MIMO receivers having one or more additional receive paths

In one embodiment, a network system has a plurality of access points, wherein each access point can be used for wireless communication with at least one station, wherein each access point can (1) receive a probe signal with either a first or second channel frequency and (2) generate and transmit, in response to the probe signal, a response signal with the first or second channel frequency. At least one access point selects at least one channel frequency for the wireless communication with the at least one station on the basis of at least one response signal received with the first channel frequency as transmitted by any of the other access points and/or at least one response signal received with the second channel frequency as transmitted by any of the other access points.

Network system comprising access points

Medium access control device () for a mobile network station () or an access point (AP) in a wireless local area network (), having controlling means (), processing means () and transmitting and receiving means (); the controlling means () being arranged to control transmission and reception of radio frequency data signals containing data symbols; the transmitting and receiving means () being arranged for transmission and reception of electromagnetic data signals; the processing means () being arranged for detecting a first signal portion and a second signal portion in the received data signal, the second signal portion following the first signal portion and having a signal coding differing from a signal coding of the first signal portion.

Wireless LAN with enhanced carrier sensing

In the method of dynamically setting at least one threshold at an access point in a wireless local area network, signals from other access points are sensed, and a carrier detect threshold is determined based on the received signal strength of at least one of the sensed signals.

Method of dynamically setting at least one threshold at an access point in a wireless local area network and the access point

A communication system with a plurality of access points (AP, APAP) and at least one network station (), the network station () being arranged to communicate with one of the plurality of access points (AP, APAP) through a wireless communication protocol, each access point (AP, APAP) is able to monitor its access point traffic load and transmit an access point traffic load parameter (ATT) to the network station (), and the network station () is able to monitor its network station traffic load; store a network station traffic load parameter (AUTT); receive access point traffic load parameters (ATT) from the access points (AP, APAP); and select a communication connection with one of the access points (APAPAP) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Method and device for communicating at least one packet of data with a predetermined packet size over a communication channel from a transmitter to a receiver, the transmitter having a memory for storing a common set of data rates, the method including the steps of fragmenting the at least one packet into a number of frames with a predetermined frame size by the transmitter, automatically selecting a combination of frame size and one of the common set of data rates by the transmitter such that the transmission time of each of the frames is limited to a predefined value, and transmitting each frame over the communication channel by the transmitter.

Method and device for robust fallback in data communication systems

The present invention relates to a wireless local area network station comprising a signal processing element, a carrier detect sensing element, a defer behavior sensing element, and memory. The network station transmits and receives signals within a communication cell that defines a carrier detect zone and a defer zone around an access point. The network station associates with the access point by transmitting an association request to the access point and by receiving an association response from the access point during entry of the network station into the cell. The network station receives a preferred carrier detect threshold level value and a preferred defer behavior threshold level value from the access point and stores the carrier detect threshold and defer behavior threshold level values in its memory for use during operation while being associated with the access point.

Wireless LAN with carrier sense threshold adaption

A method and system of operating a wireless local area network station adapted to transmit and receive a signal within a communication cell. The method includes the steps of establishing a carrier detect threshold level, establishing a defer threshold level, and transmitting a signal when the signal level detected by the network station is above the defer threshold level. Additionally, the method further includes the step of receiving a signal transmission intended for the network station when the power of the received signal transmission is above the carrier detect threshold level.

Wireless local area network with enhanced carrier sense provision

A receiver, and a method for operating the receiver, for a station in a wireless local area network using a common wireless communication channel and employing a CSMA/CA (carrier sense multiple access with collision avoidance) protocol includes various modes. In normal mode, the receiver follows typical states in order to detect a message and demodulate data from the message properly. Meanwhile, a process implements a message-in-message (MIM) mode when an energy increase above a specified level is detected. While in the MIM mode, if a carrier is detected, the energy increase is caused by a new message; otherwise, the energy increase is caused by an interfering station. If the carrier is detected, the receiver begins retraining so that it can start receiving the new message as soon as the first message ends. If no carrier is detected, the receiver waits a specified time to detect a carrier or for the end of the first message, after which the receiver returns to the beginning of the normal mode. While in the normal mode, if a message is detected that is not addressed to the station, the receiver enters a hunt mode. While in the hunt mode, the receiver waits for the current message to finish. At the same time, a process implements retraining when both an energy increase above a specified level and a carrier are detected. If no carrier is detected within a specified time, or if the energy level decreases below the specified level, the receiver returns to the beginning of the normal mode.

Wireless lan with enhanced capture provision

For use in a direct sequence spread spectrum ('DSSS') receiver adapted to receive a differential phase shift keyed ('DPSK') packet on a channel, the DPSK packet having a training preamble and a data portion, a system to improve detection of the packet under degraded channel conditions, comprising: (1) a detection circuit that derives phase information from symbols in the packet and a weight that is a function of an estimated power profile for the channel and (2) a computation circuit that computes a weighted average for the phase information using the weight, the weighted average being power profile-based to allow the receiver to detect the data contained in the packet more reliably under the degraded channel conditions.

Growing community of inventors

Nieuwegein, Netherlands

Adriaan Kamerman