公开(公告)号：JPH1065669A

公开(公告)日：1998-03-06

申请号：JP14639697

申请日：1997-06-04

Applicant: IBM

Inventor： KERMANI PARVIZ ,  MCKAY DANNY N ,  NAGHSHINEH MAHMOUD ,  NOVAK FRANK PETER ,  REZVANI BABAK

IPC: H04L12/28 ,  H04L12/413

Abstract: PROBLEM TO BE SOLVED: To enable an adaptive access protocol by deciding the presence or absence of a hidden node. SOLUTION: If a source address (s) is not contained in a table after detection of a data frame, the address (s) is added to the table (1. 1). In any case, the status of the address (s) is written as 1 (1. 2) showing that the network nodes are included in the range of a node (n), and 0 sometimes shows that the network nodes are excluded out of the range of the node (n). If a destination address (d) of the frame is not contained in the table, the address (d) is added to the table (1. 3). In any case, the status of the address (d) is written as 0 (1. 4). Only the packet that is safely received is used to this algorithm in order to avoid such a case where a hidden node is identified when no ACK is transmitted due to a collision or a transmission error.

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.

公开(公告)号：CA2218908C

公开(公告)日：2000-02-22

申请号：CA2218908

申请日：1997-07-08

Applicant: IBM

Inventor： REZVANI BABAK ,  OLSEN CLAUS M ,  NAGHSHINEH MAHMOUD ,  MCKAY DANNY NEIL ,  HORTENSIUS PETER D ,  KERMANI PARVIZ

IPC: H04L29/06 ,  H04L29/04

Abstract: In a communications network having a plurality of stations and a shared common communications medium using a collision avoidance media access protocol for communication between the stations; in which medium access is granted to a pair of stations obtaining a successful reservation of the medium; the pair of stations comprising a requester station and a target station, the requester station comprises a primary station, and the target station comprises a secondary station; wherein the primary station coordinates communication to the secondary station; other stations in range of the primary station comprises observing stations; the improvement comprising a method of joining a reservation wherein the primary station invites a selected observing station to participate in communication with it; the selected observing station responding thereto where the primary joins the selected observing station as a secondary station within the reservation in replacement of previous secondary station in the reservation, the primary station thereafter sending data to the replacement secondary station.

公开(公告)号：CA2219046A1

公开(公告)日：1998-01-09

申请号：CA2219046

申请日：1997-07-08

Applicant: IBM

Inventor： KERMANI PARVIZ ,  HORTENSIUS PETER D ,  REZVANI BABAK ,  OLSEN CLAUS M ,  NAGHSHINEH MAHMOUD ,  MCKAY DANNY NEIL

IPC: H04L69/14 ,  H04L29/06

Abstract: In a communication network having a plurality of stations and a shared co mmoncommunications medium using a collision avoidance me dia access protocol for communication between the stations; in which medium access is granted to a p air of stations obtaining a successful reservation of the medium; the pair of stati ons comprising a requester station and a target station, wherein multiple stations may requ est access to the medium to send data, a method of establishing a reservation between stat ionscomprising: the requesting stations sending Request- to-Send (RTS) control frames and the receiving stations responding as appropriate with Clear-to-Send (CTS) contro l frames; wherein a requesting node aborts the reservation if the medium becomes activ e between its RTS transmission and the corresponding CTS response of its target statio n; performing arbitration by stations receiving the RTS transmission as follows: if a rece iving station receives multiple Request-to-Send (RTS) control frames directed to the recei ving station during a contention period, the receiving station responds to the last RTS c ontrol frame received by transmitting Clear-to-Send (CTS) control frames; if the receivin g station receives multiple RTS control frames directed to different receiving station s during a contention period, the receiving station will respect the first RTS control frame received.

公开(公告)号：CA2219044A1

公开(公告)日：1998-01-09

申请号：CA2219044

申请日：1997-07-08

Applicant: IBM

Inventor： REZVANI BABAK ,  NAGHSHINEH MAHMOUD ,  MCKAY DANNY NEIL ,  KERMANI PARVIZ ,  HORTENSIUS PETER D ,  OLSEN CLAUS M

IPC: H04L29/06

Abstract: In a communications network having a plurality of stations and a shared common communications medium using a collision avoidance media access protocol for communication between the stations; in which medium access is granted to a pair of stations obtaining a successful reservation of the medium; the pair of stations comprising a requester station and a target station; wherein the communication medium is reserved based on requester transmission of a Request-to-Send (RTS) control frame and the reply thereto by a target station with a Clear-to-Send control frame when the target station is ready to receive data; a method of transmission control comprising the following; if the target station is not ready to receive data from the requesting station the sending of a Hold-to-Send (HTS) control frame by the target station to the requesting station; the target station recording identification of the requesting station; the requesting station recording the target station as being inhibited.

公开(公告)号：CA2219046C

公开(公告)日：2001-08-07

申请号：CA2219046

申请日：1997-07-08

Applicant: IBM

Inventor： REZVANI BABAK ,  HORTENSIUS PETER D ,  OLSEN CLAUS M ,  NAGHSHINEH MAHMOUD ,  KERMANI PARVIZ ,  MCKAY DANNY NEIL

IPC: H04L69/14 ,  H04L29/06

Abstract: In a communication network having a plurality of stations and a shared co mmoncommunications medium using a collision avoidance me dia access protocol for communication between the stations; in which medium access is granted to a p air of stations obtaining a successful reservation of the medium; the pair of stati ons comprising a requester station and a target station, wherein multiple stations may requ est access to the medium to send data, a method of establishing a reservation between stat ionscomprising: the requesting stations sending Request- to-Send (RTS) control frames and the receiving stations responding as appropriate with Clear-to-Send (CTS) contro l frames; wherein a requesting node aborts the reservation if the medium becomes activ e between its RTS transmission and the corresponding CTS response of its target statio n; performing arbitration by stations receiving the RTS transmission as follows: if a rece iving station receives multiple Request-to-Send (RTS) control frames directed to the recei ving station during a contention period, the receiving station responds to the last RTS c ontrol frame received by transmitting Clear-to-Send (CTS) control frames; if the receivin g station receives multiple RTS control frames directed to different receiving station s during a contention period, the receiving station will respect the first RTS control frame received.

公开(公告)号：CA2210030C

公开(公告)日：2000-10-31

申请号：CA2210030

申请日：1997-07-08

Applicant: IBM

Inventor： KERMANI PARVIZ ,  NAGHSHINEH MAHMOUD ,  MCKAY DANNY NEIL ,  HORTENSIUS PETER D ,  OLSEN CLAUS M ,  REZVANI BABAK

IPC: H04B7/26 ,  H04L12/28 ,  H04L12/413 ,  H04L12/56 ,  H04L29/06 ,  H04L12/24

Abstract: Methods and arrangements are described herein to improve 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 exchanged 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. In essence, this reduces the additional time in contention mode. Furthermore, in another aspect of the invention observing stations which are not participating in the reservation can be invited to join the initial reservation as secondary stations if this does not cause any interference to any other existing reservations. In other aspects of the invention, we define a number of additional extensions in the RTS/CTS exchange to improve the efficiency of the medium reservation by piggy-backing any reservation specific signals on data packets or defining new response frames such as Hold-to-Send (HTS) and Free-to-Send (FTS) which are used for flow control techniques in response to a congested receiving station.

公开(公告)号：CA2219044C

公开(公告)日：2000-03-21

申请号：CA2219044

申请日：1997-07-08

Applicant: IBM

Inventor： OLSEN CLAUS M ,  KERMANI PARVIZ ,  NAGHSHINEH MAHMOUD ,  MCKAY DANNY NEIL ,  REZVANI BABAK ,  HORTENSIUS PETER D

IPC: H04L29/06

Abstract: In a communications network having a plurality of stations and a shared common communications medium using a collision avoidance media access protocol for communication between the stations; in which medium access is granted to a pair of stations obtaining a successful reservation of the medium; the pair of stations comprising a requester station and a target station; wherein the communication medium is reserved based on requester transmission of a Request-to-Send (RTS) control frame and the reply thereto by a target station with a Clear-to-Send control frame when the target station is ready to receive data; a method of transmission control comprising the following; if the target station is not ready to receive data from the requesting station the sending of a Hold-to-Send (HTS) control frame by the target station to the requesting station; the target station recording identification of the requesting station; the requesting station recording the target station as being inhibited.

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.

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.