公开(公告)号：DE69426788T2

公开(公告)日：2001-08-02

申请号：DE69426788

申请日：1994-04-13

Applicant: IBM

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

IPC: H04J3/00 ,  H04B7/24 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56 ,  H04B7/204

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.

公开(公告)号：DE69426788D1

公开(公告)日：2001-04-12

申请号：DE69426788

申请日：1994-04-13

Applicant: IBM

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

IPC: H04J3/00 ,  H04B7/24 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56 ,  H04B7/204

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.

公开(公告)号：IT1148833B

公开(公告)日：1986-12-03

申请号：IT2242680

申请日：1980-05-30

Applicant: IBM

Inventor： BAKER CURETON DAVID ,  BANTZ DAVID FREDERICK ,  EVANGELISTI CARLO JOHN

IPC: G06F12/02 ,  G06F12/06 ,  G06F13/14 ,  G06F13/16 ,  G06F13/36 ,  G06F15/16 ,  G06F15/173 ,  G06F

Abstract: The technique for transmitting address information between a processor and a plurality of memory subsystems in a common bus communication system. The width of the address field is greater than the number of lines on the bus. For example, addresses are three bytes wide, and the bus is one byte wide, thereby reducing the number of pins required on the processor and the subsystems. For communication between the processor and a given memory subsystem, only those bytes of a selected address which differ from the corresponding bytes of a previous address are transmitted sequentially for accessing a selected memory location.

公开(公告)号：DE3069039D1

公开(公告)日：1984-09-27

申请号：DE3069039

申请日：1980-12-04

Applicant: IBM

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

IPC: G06F11/22 ,  G01R31/317 ,  G01R31/3185 ,  G06F11/267 ,  G06F11/36 ,  G06F11/26

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.