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公开(公告)号：DE69209968D1
公开(公告)日：1996-05-23
申请号：DE69209968
申请日：1992-09-29
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA
Abstract: A wireless communications network includes a local area network connected to a plurality of nodes (12) which perform bidirectional wireless communication with mobile stations (10) as controlled by a controller (3). Each node has a geographic area, termed a cell, within which mobile stations can communicate with the node associated with the cell. A cell interference graph is read into the controller, and a maximal independent set of nodes is determined. Each node in the maximal independent set of nodes is pint in a set termed ACTIVE for performing wireless communication with mobile stations in their respective cells. Nodes which are not in the maximal independent set of nodes is put in a set termed WAITING to wait for permission to enter the set ACTIVE. A node in the set ACTIVE which has completed communications sends a completion signal to the controller. The controller then examines which of the nodes in the set WAITING is not adjacent to another node in the set ACTIVE, and such nodes are entered in a set termed CANDIDATES. Nodes in the set CANDIDATES are moved to the set ACTIVE according to a predetermined criteria.
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公开(公告)号：DE69228156T2
公开(公告)日：1999-08-05
申请号：DE69228156
申请日：1992-07-11
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA , HUANG CHIA-CHI
Abstract: A method and apparatus for conserving battery power in a wireless link adapter of a battery operated computer such as a portable laptop computer, as controlled by a scheduled multiaccess protocol. The portable computer is operable as a mobile unit in a multi-cell wireless network. The scheduled access multiaccess protocol is implemented to effectively conserve battery power by suitable control of the state of the controller, the transmitter and receiver units at the wireless link adapter by scheduling when the adapter is in a normal running mode, or a standby mode in which power is conserved.
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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
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.
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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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Patent Agency Ranking
公开(公告)号：DE69209968T2
公开(公告)日：1996-10-10
申请号：DE69209968
申请日：1992-09-29
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA
Abstract: A wireless communications network includes a local area network connected to a plurality of nodes (12) which perform bidirectional wireless communication with mobile stations (10) as controlled by a controller (3). Each node has a geographic area, termed a cell, within which mobile stations can communicate with the node associated with the cell. A cell interference graph is read into the controller, and a maximal independent set of nodes is determined. Each node in the maximal independent set of nodes is pint in a set termed ACTIVE for performing wireless communication with mobile stations in their respective cells. Nodes which are not in the maximal independent set of nodes is put in a set termed WAITING to wait for permission to enter the set ACTIVE. A node in the set ACTIVE which has completed communications sends a completion signal to the controller. The controller then examines which of the nodes in the set WAITING is not adjacent to another node in the set ACTIVE, and such nodes are entered in a set termed CANDIDATES. Nodes in the set CANDIDATES are moved to the set ACTIVE according to a predetermined criteria.
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公开(公告)号：DE69531076T2
公开(公告)日：2004-05-06
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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公开(公告)号：DE69228156D1
公开(公告)日：1999-02-25
申请号：DE69228156
申请日：1992-07-11
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA , HUANG CHIA-CHI
Abstract: A method and apparatus for conserving battery power in a wireless link adapter of a battery operated computer such as a portable laptop computer, as controlled by a scheduled multiaccess protocol. The portable computer is operable as a mobile unit in a multi-cell wireless network. The scheduled access multiaccess protocol is implemented to effectively conserve battery power by suitable control of the state of the controller, the transmitter and receiver units at the wireless link adapter by scheduling when the adapter is in a normal running mode, or a standby mode in which power is conserved.
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公开(公告)号：DE3788830T2
公开(公告)日：1994-06-23
申请号：DE3788830
申请日：1987-05-08
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA , STONE HAROLD STUART
Abstract: An adaptive mechanism is presented in the context of optimization of expert system applications. Both single and multiple processor implementations are disclosed. The mechanism is used to maintain a near-optimal sequence for scanning rule lists in expert systems. For a program containing a sequential-decision, chain with many independent or mutually exclusive outcomes with each decision having associated with it some fixed cost and probability, the adaptive mechanism tends to produce the optimal ordering automatically from repeated observations of the execution of the decision chain.
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公开(公告)号：DE3788830D1
公开(公告)日：1994-03-03
申请号：DE3788830
申请日：1987-05-08
Applicant: IBM
Inventor： NATARAJAN KADATHUR SUBRAMANYA , STONE HAROLD STUART
Abstract: An adaptive mechanism is presented in the context of optimization of expert system applications. Both single and multiple processor implementations are disclosed. The mechanism is used to maintain a near-optimal sequence for scanning rule lists in expert systems. For a program containing a sequential-decision, chain with many independent or mutually exclusive outcomes with each decision having associated with it some fixed cost and probability, the adaptive mechanism tends to produce the optimal ordering automatically from repeated observations of the execution of the decision chain.
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