Abstract: The invention relates to a communication device (2) comprising an antenna system (4) provided with at least one antenna (6a, 6b, 6c) for receiving a radio signal and supplying a received radio signal to an output (8) of the antenna system, a low noise amplifier (10) for amplification of the received radio signal to obtain an amplified radio signal, and a processing unit (12) for processing the amplified radio signal. The antenna system (4) 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 (14) generated by the processing unit (12).

Abstract: A communication protocol based on CSMA between a node, in particular an electronic label, and a network coordinator is disclosed. The node comprises:—a transceiver provided for communication with a network coordinator, wherein the transceiver handles a transmission channel based on CSMA;—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:—sending recurrently a data request packet;—going to a low power mode after sending the data request packet; and—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.

Abstract: The invention relates to a communication device (2) comprising an antenna system (4) provided with at least one antenna (6a, 6b, 6c) for receiving a radio signal and supplying a received radio signal to an output (8) of the antenna system, a low noise amplifier (10) for amplification of the received radio signal to obtain an amplified radio signal, and a processing unit (12) for processing the amplified radio signal. The antenna system (4) 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 (14) generated by the processing unit (12).

Abstract: A communication protocol based on CSMA between a node, in particular an electronic label, and a network coordinator is disclosed. The node comprises: a transceiver provided for communication with a network coordinator, wherein the transceiver handles a transmission channel based on CSMA; 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: sending recurrently a data request packet; going to a low power mode after sending the data request packet; and 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.

Abstract: A communication system with a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), the network station (5, 6) being arranged to communicate with one of said the plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, each access point (AP1, AP2, AP3) is able to monitor its access point traffic load and transmit an access point traffic load parameter (ATT) to the network station (5, 6), and the network station (5, 6) 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 (AP1, AP2, AP3); and select a communication connection with one of the access points (AP1, AP2, AP3) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Medium access control device (301) for a mobile network station (3, 4, 5) or an access point (AP1) in a wireless local area network (1), having controlling means (302), processing means (303) and transmitting and receiving means (304); the controlling means (302) being arranged to control transmission and reception of radio frequency data signals containing data symbols; the transmitting and receiving means (304) being arranged for transmission and reception of electromagnetic data signals; the processing means (303) 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.

Abstract: 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.

Abstract: 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.

Abstract: A communication system with a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), the network station (5, 6) being arranged to communicate with one of said the plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, each access point (AP1, AP2, AP3) is able to monitor its access point traffic load and transmit an access point traffic load parameter (ATT) to the network station (5, 6), and the network station (5, 6) 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 (AP1, AP2, AP3); and select a communication connection with one of the access points (AP1, AP2, AP3) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Abstract: A communication system with a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), the network station (5, 6) being arranged to communicate with one of the plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, each access point (AP1, AP2, AP3) is able to monitor its access point traffic load and transmit an access point traffic load parameter (ATT) to the network station (5, 6), and the network station (5, 6) 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 (AP1, AP2, AP3); and select a communication connection with one of the access points (AP1, AP2, AP3) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Abstract: 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.

Abstract: Mutual interference experienced between co-located WLAN and BT devices is minimized. An improved wireless local area network (WLAN) scheme using fragmentation, that itself mitigates BLUETOOTH™—related interference, without relying on a presumed cooperation from co-located BLUETOOTH devices. The use of fragmentation in a WLAN network allows a longer concatenated period of WLAN activity, with corrupted segments being retried. Therefore, the chances of getting a full frame transferred during the repetitive interference by BT voice is greatly improved. A coexistence scheme is provided that is active in the MAC layer of a Wireless LAN (WLAN) device, aiming to make optimal use of the non-occupied BT slots for both uplink and downlink WLAN communication. The co-existence scheme improves throughput performance for active co-located WLAN and BT devices.

Abstract: 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.

Abstract: 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.

Abstract: A method and apparatus are provided for automatic data rate control in wireless communication systems, such as wireless LANs. A data rate controller adapts a transmission rate of said data based on a signal quality and a transmit power level. The data rate controller can also adapt the transmission rate based on one or more of amplifier non-linearities, anticipated signal quality for a next frame transmission, regulatory emission limits and data rate advice. The data rate advice will decrease a data rate if a current signal quality is below a minimum required signal quality for a given data rate and increase a data rate if a current signal quality is above a minimum required signal quality for a given data rate. A probation mechanism allows a higher rate to be evaluated before switching to the higher rate permanently. A retry balance mechanism forces a rate fallback when a number of failed transmission exceeds a predefined threshold.

Abstract: 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.