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公开(公告)号：JPH10135954A
公开(公告)日：1998-05-22
申请号：JP14261097
申请日：1997-05-30
Applicant: IBM
Inventor： MCKAY DANNY NEIL , NAGSHINEH MAHMOUD , OLSEN CLAUS MICHAEL , REZVANI BABAK , KERMANI PARVIZ
IPC: H04B7/26 , H04L12/28 , H04L12/413 , H04L12/56
Abstract: PROBLEM TO BE SOLVED: To improve the performance of a distributed medium access control protocol on the basis of RTS/CTS. SOLUTION: A medium is reserved by the hierarchical system that reserves a common share medium at first for two stations called participation stations. All other stations called observation station are in standstill for a time reserved for the participation stations. In this system, the common share medium is reserved for a subset of a plurality of devices. Stations attribute of a master station (or primary station) and a subordinate station (or secondary station) is provided to devices taking each part for the period called a reservation period, and a medium is shared in common by other medium coordination algorithm. The algorithm need not be the same as that used for reserving the medium for the reservation period at first. A device taking its part after reserving a medium building up conventional 2-point connection between the devices taking part therein.
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公开(公告)号：GB2314487A
公开(公告)日：1997-12-24
申请号：GB9712244
申请日：1997-06-13
Applicant: IBM
Inventor： GFELLER FRITZ RUDOLF , HORTENSIUS PETER DIRK , KAM PATRICK K , KERMANI PARVIZ , MCKAY DANNY M , NAGHSHINEH MAHMOUD , OLSEN CLAUS MICHAEL , REZVANI BABAK
IPC: H04L1/00 , H04L1/08 , H04L12/413
Abstract: A method of wireless communications in a network having a plurality of terminals comprises transmitting media access coordination information at a first repetition rate and other information at a second repetition rate lower than said first repetition rate. A Media Access and contention resolution scheme for using multirate wireless,/infrared communication is described. In such an environment, each physical layer frame is broken into two portions: (1) the robust header portion which contains all svmbols important to the MAC protocol and media coordination and is sent with a repetition rate Rmax where Rmax is selected in such a way that all stations within the interference environment can decode the reservation symbols with a desired probability; and (2) data symbols which are sent with a repetition rate R where R can be less than Rmax. Here R depends on the channel conditions at any destination with respect to the source station transmitting such data symbols.
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Patent Agency Ranking
公开(公告)号：DE112005002614T5
公开(公告)日：2007-09-27
申请号：DE112005002614
申请日：2005-05-25
Applicant: IBM
Abstract: A computer and method that control access to a network. The computer includes an application that shrinks the window of opportunity for a network attack and reduces power consumption by automatically causing a computer to connect to the network when access is needed and to disconnect the computer from the network when access is not needed. The computer is automatically disconnected when it is deemed that network access is no longer needed, such as after a time period of no network activity. In turn, when the user, or the system, needs access to the network, the computer is automatically reconnected to the network. A software daemon on the computer may temporarily reconnect the computer to the network to access a server on the network to determine if attempts have been made to access the computer.
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公开(公告)号：GB2434012A
公开(公告)日：2007-07-11
申请号：GB0707950
申请日：2007-04-24
Applicant: IBM
Abstract: A computer and method that control access to a network. The computer includes an application that shrinks the window of opportunity for a network attack and reduces power consumption by automatically causing a computer to connect to the network when access is needed and to disconnect the computer from the network when access is not needed. The computer is automatically disconnected when it is deemed that network access is no longer needed, such as after a time period of no network activity. In turn, when the user, or the system, needs access to the network, the computer is automatically reconnected to the network. A software daemon on the computer may temporarily reconnect the computer to the network to access a server on the network to determine if attempts have been made to access the computer.
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公开(公告)号：GB2314487B
公开(公告)日：2001-01-10
申请号：GB9712244
申请日：1997-06-13
Applicant: IBM
Inventor： GFELLER FRITZ RUDOLF , HORTENSIUS PETER DIRK , KAM PATRICK K , KERMANI PARVIZ , MCKAY DANNY M , NAGHSHINEH MAHMOUD , OLSEN CLAUS MICHAEL , REZVANI BABAK
IPC: H04L1/00 , H04L1/08 , H04L12/413
Abstract: In a wireless multi-rate communications system, a method for extending the range of communications in the system by dividing the physical layer frame into two portions: a robust header portion and a body, where the repetition rate of the data symbols in the header portion is greater than or equal to the repetition rate of the data symbols in the body of the frame. In this way the header can be received and decoded by all stations in the system with a high probability, while the body of the frame need only be received and decoded by the destination station to which the body of the frame is intended to be received and decoded.
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公开(公告)号：DE69732064T2
公开(公告)日：2005-12-08
申请号：DE69732064
申请日：1997-06-25
Applicant: IBM
Inventor： MCKAY DANNY NEIL , NAGSHINEH MAHMOUD , OLSEN CLAUS MICHAEL , REZVANI BABAK , KERMANI PARVIZ
IPC: H04B7/26 , H04L12/28 , H04L12/413 , H04L12/56 , H04L29/02
Abstract: A communication network and method improves the performance (measured e.g. in terms of throughput) of a RTS/CTS based distributed media access control protocol. The medium reservation is done in a hierarchical fashion where first the shared medium is reserved for two stations called the participants. All other stations called observers stay quiet during the time reserved for the participants. In this fashion, a shared medium can be reserved for a subset of the plurality of devices. During this period called the reserved period, a master (or primary), and a slave (or secondary) station attribute can be given to the participating devices and the medium can be shared using another medium coordination algorithm which is not necessarily the same as the one used to reserve the medium for a reserved period in the first place. After the medium is reserved, the participating devices can establish a conventional point-to-point connection within the reserved time period between participating devices for a predefined period of time. Specifically, the primary attribute can be exchanges with a secondary attribute which in effect gives the control of the shared medium during the reserved period to another station different from the one that originally was assigned the primary attribute. During the reserved time, the secondary can signal the primary station that it has data to send to the primary station and request that the primary and secondary roles or attributes to be exchanged. In the case that a role exchange takes place, the control of the medium is transferred from one station to another and data transfer in an opposite direction can take place without requiring another reservation attempt.
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公开(公告)号：DE69732064D1
公开(公告)日：2005-02-03
申请号：DE69732064
申请日：1997-06-25
Applicant: IBM
Inventor： MCKAY DANNY NEIL , NAGSHINEH MAHMOUD , OLSEN CLAUS MICHAEL , REZVANI BABAK , KERMANI PARVIZ
IPC: H04B7/26 , H04L12/28 , H04L12/413 , H04L12/56 , H04L29/02
Abstract: A communication network and method improves the performance (measured e.g. in terms of throughput) of a RTS/CTS based distributed media access control protocol. The medium reservation is done in a hierarchical fashion where first the shared medium is reserved for two stations called the participants. All other stations called observers stay quiet during the time reserved for the participants. In this fashion, a shared medium can be reserved for a subset of the plurality of devices. During this period called the reserved period, a master (or primary), and a slave (or secondary) station attribute can be given to the participating devices and the medium can be shared using another medium coordination algorithm which is not necessarily the same as the one used to reserve the medium for a reserved period in the first place. After the medium is reserved, the participating devices can establish a conventional point-to-point connection within the reserved time period between participating devices for a predefined period of time. Specifically, the primary attribute can be exchanges with a secondary attribute which in effect gives the control of the shared medium during the reserved period to another station different from the one that originally was assigned the primary attribute. During the reserved time, the secondary can signal the primary station that it has data to send to the primary station and request that the primary and secondary roles or attributes to be exchanged. In the case that a role exchange takes place, the control of the medium is transferred from one station to another and data transfer in an opposite direction can take place without requiring another reservation attempt.
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