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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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公开(公告)号：DE69129439T2
公开(公告)日：1999-02-04
申请号：DE69129439
申请日：1991-10-07
Applicant: IBM
Inventor： HARRISON COLIN GEORGE , HORTENSIUS PETER DIRK
IPC: H04B10/00 , H04B10/10 , H04B10/118 , H04B10/22 , H04L12/28 , H04W48/08 , H04W72/04 , H04L12/40 , H04Q7/20 , H04B7/26
Abstract: Method and apparatus for coordinating a usage of a wireless transmission medium amongst a plurality of transmission units (12). The transmission medium is of a type that is utilized in accordance with a protocol having a transmission period that is comprised of a plurality of consecutively occurring transmission sub-periods. A method includes the following steps. A data structure (28a) is periodically circulated amongst the transmission units, the data structure being expressive of an identification of each of the transmission units and also expressive of an identification of an assigned transmission sub-period or sub-periods, if any, during which each of the transmission units is permitted to transmit on the wireless medium. The step of circulating includes the following steps: (a) receiving the data structure from a first transmission unit with a second transmission unit; (b) responsive to the receipt of the data structure at the second transmission unit processing the data structure in accordance with an amount, if any, of impending transmission activity to modify the assignments of sub-periods therein; and (c) transmitting the modified data structure to another one of the transmission units. A method of synchronizing the plurality of transmission units to a slotted transmission protocol is also disclosed.
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公开(公告)号：DE69121837D1
公开(公告)日：1996-10-10
申请号：DE69121837
申请日：1991-10-07
Applicant: IBM
Abstract: Methods and apparatus for operating an optical communications system having at least two communicating entities (10,12). In accordance with a method of the invention a first step transmits communication link control information from a first entity to a second entity over a first optical channel having a first data bit rate. Responsive to the transmitted communication link control information, a second step of the method transmits data information from the second entity to the first entity over a second optical channel having a second data bit rate that is greater than the first data bit rate. The first optical channel is preferably a relatively low-bandwidth diffuse transmission infrared radiation channel. The second optical channel is preferably a relatively high-bandwidth infrared channel. One of the entities is a network adapter coupled to a wired network. The network adapter is preferably ceiling mounted. The other entity may be a mobile data processor. A plurality of mobile data processors may be served by one network adapter.
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公开(公告)号：DE69129439D1
公开(公告)日：1998-06-25
申请号：DE69129439
申请日：1991-10-07
Applicant: IBM
Inventor： HARRISON COLIN GEORGE , HORTENSIUS PETER DIRK
IPC: H04B10/00 , H04B10/10 , H04B10/118 , H04B10/22 , H04L12/28 , H04W48/08 , H04W72/04 , H04L12/40 , H04Q7/20 , H04B7/26
Abstract: Method and apparatus for coordinating a usage of a wireless transmission medium amongst a plurality of transmission units (12). The transmission medium is of a type that is utilized in accordance with a protocol having a transmission period that is comprised of a plurality of consecutively occurring transmission sub-periods. A method includes the following steps. A data structure (28a) is periodically circulated amongst the transmission units, the data structure being expressive of an identification of each of the transmission units and also expressive of an identification of an assigned transmission sub-period or sub-periods, if any, during which each of the transmission units is permitted to transmit on the wireless medium. The step of circulating includes the following steps: (a) receiving the data structure from a first transmission unit with a second transmission unit; (b) responsive to the receipt of the data structure at the second transmission unit processing the data structure in accordance with an amount, if any, of impending transmission activity to modify the assignments of sub-periods therein; and (c) transmitting the modified data structure to another one of the transmission units. A method of synchronizing the plurality of transmission units to a slotted transmission protocol is also disclosed.
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公开(公告)号：DE69117869D1
公开(公告)日：1996-04-18
申请号：DE69117869
申请日：1991-10-07
Applicant: IBM
Inventor： HORTENSIUS PETER DIRK , WINBOM HAAKEN B
IPC: H04L12/28 , H04L12/413 , H04L12/40 , H04B10/10
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Patent Agency Ranking
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：DE69121837T2
公开(公告)日：1997-04-30
申请号：DE69121837
申请日：1991-10-07
Applicant: IBM
Abstract: Methods and apparatus for operating an optical communications system having at least two communicating entities (10,12). In accordance with a method of the invention a first step transmits communication link control information from a first entity to a second entity over a first optical channel having a first data bit rate. Responsive to the transmitted communication link control information, a second step of the method transmits data information from the second entity to the first entity over a second optical channel having a second data bit rate that is greater than the first data bit rate. The first optical channel is preferably a relatively low-bandwidth diffuse transmission infrared radiation channel. The second optical channel is preferably a relatively high-bandwidth infrared channel. One of the entities is a network adapter coupled to a wired network. The network adapter is preferably ceiling mounted. The other entity may be a mobile data processor. A plurality of mobile data processors may be served by one network adapter.
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公开(公告)号：DE69117869T2
公开(公告)日：1996-10-02
申请号：DE69117869
申请日：1991-10-07
Applicant: IBM
Inventor： HORTENSIUS PETER DIRK , WINBOM HAAKEN B
IPC: H04L12/28 , H04L12/413 , H04L12/40 , H04B10/10
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