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    23.
    发明专利
    未知

    公开(公告)号：BR9401518A

    公开(公告)日：1994-12-27

    申请号：BR9401518

    申请日：1994-04-18

    Applicant: IBM

    Inventor： AHMADI HAMID ,  BANTZ DAVID FREDERICK ,  BAUCHOT FREDERIC JACQUES ,  KRISHNA ARVIND ,  ORVILLE LA MAIRE RICHARD ,  NATARAJAN KADATHUR SUBRAMANYA

    IPC: H04J3/00 ,  H04B7/24 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56

    Abstract: A Medium Access (MAC) Protocol is utilized for wireless radio access for a plurality of remote stations to a base station on a LAN. The MAC protocol is based on a reservation scheme for user data traffic and a random access technique for control and signalling traffic. There is a time division fixed frame structure in which time is slotted, and time slots are grouped into fixed frames consisting of data and control subframes or periods. The fixed frame structure consists of three periods (A, B, and C) along with their respective headers. The first period, the A period, is the outbound channel which is used exclusively for data transfer from the base station to the remote stations. The following period, the B period, is the inbound channel that is used for contention-free data transfer from the remote stations to the base station. The allocation of the data slots in the A and B periods is performed by the base station. The last period of the frame, designated as the C period, is the control channel used for the transmission of reservation requests and data from the remote stations to the base station in a random-access contention mode using a slotted Aloha protocol. The duration of the three periods may be varied using a movable boundary technique. The base station estimates the number of actively transmitting remote stations utilizing feedback information from the remote stations. This estimate is broadcast to the remote stations as control indicia to control their transmission attempts in the C period, thus yielding high transmission efficiency.

    24.
    发明专利
    未知

    公开(公告)号：DE3685065D1

    公开(公告)日：1992-06-04

    申请号：DE3685065

    申请日：1986-07-18

    Applicant: IBM

    Inventor： BANTZ DAVID FREDERICK ,  EVANGELISTI CARLO JOHN

    IPC: G06F3/153 ,  G06F3/048 ,  G06F3/14 ,  G06F17/50 ,  G06T1/00 ,  G06T11/00 ,  G06T15/06 ,  G06T15/40 ,  G09G5/14 ,  G09G1/00 ,  G06F15/72

    Abstract: In a method for rapid windowing of display information in a computer system image data is maintained in a hierarchical data tree structure. The complete image field (1), within which the image is defined, is divided into cells (7). The window is defined within this field and a field of possible interest (5) is defined around the window. Then, for each node in the tree, summary node data is computed which identifies those cells within the field of possible interest which are at least partially occupied by the part of the image defined at that node. By traversing the tree it is then possible to identify rapidly the image data to be windowed.

    26.
    发明专利
    未知

    公开(公告)号：IT1149865B

    公开(公告)日：1986-12-10

    申请号：IT2639680

    申请日：1980-12-03

    Applicant: IBM

    Inventor： BANTZ DAVID FREDERICK ,  EVANGELISTI CARLO JOHN ,  NELSON ROBERT ARTHUR

    IPC: G06F11/22 ,  G01R31/317 ,  G01R31/3185 ,  G06F11/267 ,  G06F11/36 ,  G06G

    Abstract: An arrangement is described comprising a diagnostic computer (11) connected to a host computer (12) for the purpose of troubleshooting the host computer's hardware and software. The arrangement includes an interface unit (13) comprising specific controls (31, 33, 35) with transfer and mask registers between the diagnostic computer and the host, and control units (22, 23) in the diagnostic computer, to perform functions required by the user of the system. The arrangement is specifically designed for use with a host computer comprising a level-sensitive scan (LSSD) register.

    COMMUNICATION SYSTEM
    27.
    发明专利
    COMMUNICATION SYSTEM 未知

    公开(公告)号：DE3163182D1

    公开(公告)日：1984-05-24

    申请号：DE3163182

    申请日：1981-06-03

    Applicant: IBM

    Inventor： BANTZ DAVID FREDERICK ,  CHOQUET MICHEL FRANCOIS ,  ROSENFELD JACK LEE

    IPC: H04L29/08 ,  G06F13/14 ,  G06F15/16

    Abstract: A communication system includes a plurality of requestors and a plurality of responders representing resources. A protocol exercised by all elements provides accurate and consistent interconnection of all elements in a system where messages may be delayed or lost. Requestors are provided with means to transmit a request for use of a plurality of resources, respond to acceptances from one or more responders and create a cooperative relationship by transmitting a confirmation to one responder and cancellation of the request to all other responders. Responders become committed to a requestor by signalling an acceptance to a request if a previous acceptance has not been transmitted, or if the resource is not already committed to another requestor, and subsequent confirmation signal is received. The responder does not become committed after transmitting an acceptance if the next signal directed to it from the requestor is a request cancellation. Request signals and cancellation signals by a requestor can either be broadcast simultaneously to all responders of a class or transmitted to particular, designated responders, one at a time.

    29.
    发明专利
    未知

    公开(公告)号：DE69531076D1

    公开(公告)日：2003-07-24

    申请号：DE69531076

    申请日：1995-04-03

    Applicant: IBM

    Inventor： HUANG CHIA-CHI ,  BANTZ DAVID FREDERICK ,  BAUCHOT FREDERIC ,  NATARAJAN KADATHUR SUBRAMANYA ,  NARASIMHAN ANAND ,  WETTERWALD MICHELE MARIE

    IPC: G06F13/00 ,  H04L12/28 ,  H04W24/00 ,  H04W36/08 ,  H04W36/30 ,  H04W84/12 ,  H04Q7/38 ,  H04B7/26 ,  H04B1/713 ,  H04L1/20

    Abstract: Methods for handoff in a wireless communication network comprised of a local area network connected to a plurality of base stations, each of which has a geographic area, defined as a cell, within which mobile stations can communicate with a base station, with each such base station being capable of performing bidirectional wireless communication with one or more of said mobile stations under control of a controller, with communication between base stations and mobile stations being performed by frequency hopping, with there being n available frequency hopping channels in a fixed frequency band, with each channel being of a same fixed duration and having a fixed frequency different than another channel. The handoff method employs structure and techniques for determining by a mobile station that the quality of transmission between it and a current base station has degraded below a predetermined performance level, structure and technique for said mobile station to listen to each of successive frequency channels for a duration substantially less than said fixed duration of a channel until it senses a transmission from another base station, and structure and techniques for transferring control of said mobile station to said another base station in response to the sensed transmission.

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