Patents by Inventor Johannes P. N. Haagh

Johannes P. N. Haagh has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6278877
    Abstract: A wireless local area network system includes a plurality of base stations connected in a wired local area network. A mobile wireless station can roam through communication cells defined by the base stations. The base stations transmit beacon messages at regular intervals. The mobile station determines the communications quality of the beacon message for the cell in which the mobile station is currently located and if this quality becomes unacceptable, switches to a search mode wherein beacon messages from any base station are received and their communications quality is determined. The mobile station switches to communicate with a base station providing a beacon message with an acceptable communications quality.
    Type: Grant
    Filed: May 21, 1993
    Date of Patent: August 21, 2001
    Assignee: Agere Systems Guardian Corporation
    Inventors: Loeke Brederveld, Wilhelmus J. M. Diepstraten, Johannes P. N. Haagh, Hendrik Moelard, Jan Hoogendoorn
  • Patent number: 6192230
    Abstract: A wireless data communication system is operable in a power saving mode wherein stations are synchronized to be in an awake state to receive synchronizing messages (TIM, PSYNC) and traffic indicator information and are changed to a doze state if they are not to receive data messages. In one embodiment all stations (20) communicate via a base station access point (16), which broadcasts synchronizing messages (TIM) at regular intervals identifying stations (20) that are to receive data messages. In another embodiment all stations (220) communicate directly with one another, one station assumes the role of a master station and broadcasts synchronizing messages (PSYNC), and stations (220) desiring to transmit data messages transmit traffic indicator messages (PTIM) to the appropriate destination stations (220), in a synchronized awake period just before the next synchronizing message (PSYNC) is expected to arrive.
    Type: Grant
    Filed: September 27, 1993
    Date of Patent: February 20, 2001
    Assignee: Lucent Technologies, Inc.
    Inventors: Hendrik van Bokhorst, Albertus M. G. Claessen, Wilhelmus J. M. Diepstraten, Johannes P. N. Haagh, Hendrik Moelard, Leo Monteban, Rienk Mud
  • Patent number: 5553316
    Abstract: A wireless local area network (10) including a plurality of stations (12) utilizes dynamic transmit power level control such that only the power level needed for reliable transmission to a particular station (12) is utilized. Each transmitted information packet (80) contains a byte (92) representing the power level at which the packet (80) was transmitted. The power level at which the packet (80) is received is measured and a path attenuation value is calculated, averaged over a plurality of packets and utilized, together with a measured interference level also transmitted in the packet (80), to determined a transmit power level for that path. Also determined is an associated defer threshold level. The transmit power levels and associated defer threshold levels are stored in a table (270).
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: September 3, 1996
    Assignee: NCR Corporation
    Inventors: Wilhelmus J. M. Diepstraten, Johannes P. N. Haagh
  • Patent number: 5519834
    Abstract: A local area network system (10) includes a host computer (14) connected in a wired LAN (12) with a plurality of bridges (18). The bridges (18) further connect with respective wireless LANs (100, 200, . . . , 600) which operate on a common wireless communication channel and contain respective pluralities of terminals (102, 202, . . . , 602). When a download operation is effected for initially starting up a new added terminal (e.g. 102-1), the bridges (18) are adapted to identify download message frames issued by the host computer (14) and retransmit each such frame (400) over the wireless communication channel in non-overlapping time intervals by applying respective different delays. Also, each download message frame is transmitted twice by each of the bridges (18).
    Type: Grant
    Filed: August 11, 1992
    Date of Patent: May 21, 1996
    Assignee: NCR Corporation
    Inventors: Adriaan Kamerman, Johannes P. N. Haagh
  • Patent number: 5151920
    Abstract: A radio LAN station is provided for receiving information frames including start and end delimiters and user data therebetween. The start and end delimiters include both data symbols and special non-data symbols. The data symbols and non-data symbols being transmitted to the radio LAN station are sent thereto via a spread spectrum signal. The data symbols and the non-data symbols are spread via first and second spreading codes, respectively. The receiving radio LAN station includes first and second correlators which respectively correlate the received spread spectrum signal against the first spreading code to retrieve the data symbols and against the second spreading code to retrieve the non-data symbols. Rectangular representations of the received data and non-data symbols are thus produced and are converted to polar form via appropriate rectangular to polar converters. The polar representations of the data and non-data symbols respectively exhibit a vector length Z and a vector length Z'.
    Type: Grant
    Filed: September 10, 1991
    Date of Patent: September 29, 1992
    Assignee: NCR Corporation
    Inventors: Johannes P. N. Haagh, Hans van Driest, Gerrit Smit
  • Patent number: 4860308
    Abstract: A data modem communication system includes a data modem transmitter adapted to transmit data on a main channel at a relatively high bit rate and to transmit data at a relatively low bit rate on a secondary channel. At the receiver, a single analog-to-digital converter (54) supplies digital signals via a notch filter (58) to the main channel receiver (60) and to the secondary channel receiver (62) wherein a single IIR low-pass digital filter (110) is utilized for processing at three different sample rates to eliminate the main channel signal with frequency conversion taking place between processing at the first and second sample rates. The invention enables the provision of a reliable secondary channel while using a minimum amount of circuitry for complex-valued digital signal processing.
    Type: Grant
    Filed: March 30, 1988
    Date of Patent: August 22, 1989
    Assignee: NCR Corporation
    Inventors: Adriaan Kamerman, Johannes P. N. Haagh
  • Patent number: RE40032
    Abstract: A wireless data communication system is operable in a power saving mode wherein stations are synchronized to be in an awake state to receive synchronizing messages (TIM, PSYNC) and traffic indicator information and are changed to a doze state if they are not to receive data messages. In one embodiment all stations (20) communicate via a base station access point (16), which broadcasts synchronizing messages (TIM) at regular intervals identifying stations (20) that are to receive data messages. In another embodiment all stations (220) communicate directly with one another, one station assumes the role of a master station and broadcasts synchronizing messages (PSYNC), and stations (220) desiring to transmit data messages transmit traffic indicator messages (PTIM) to the appropriate destination stations (220), in a synchronized awake period just before the next synchronizing message (PSYNC) is expected to arrive.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: January 22, 2008
    Assignee: Agere Systems Inc.
    Inventors: Hendrik van Bokhorst, Albertus M. G. Claessen, Wilhelmus J. M. Diepstraten, Johannes P. N. Haagh, Hendrik Moelard, Leo Monteban, Rienk Mud