公开(公告)号：DE69719573T2

公开(公告)日：2003-12-11

申请号：DE69719573

申请日：1997-11-18

Applicant: IBM

Inventor： GFELLER R ,  HIRT WALTER

IPC: H04B10/114 ,  H04J3/06 ,  H04L1/00 ,  H04L1/08 ,  H04L7/04 ,  H04L25/49 ,  H04L29/08 ,  H04B10/10 ,  H04L1/12

Abstract: Method for wireless optical communication between a transmitting station and a receiving station, whereby the transmitting station provides a Request-to-Send (RTS) frame to the receiving station to announce the transmission of a data frame, the receiving station provides a Clear-to-Send (CTS) frame to the transmitting station in case of correct reception of the RTS frame, and the transmitting station subsequently sends the data frame to the receiving station. The RTS frame comprises Preamble (PA), Synchronization (SYNC), and Robust Header (RH) fields. The RTS frame further comprises a Source Address/Destination Address field (SA/DA) and a Cyclic Redundancy Check field (CRC). Adjusting the power level of the RTS frame to be different from the nominal transmission power level at which the data frame is sent, and by variable repetition coding within the Robust Header (RH) field of the RTS frame, allows a larger dynamic range of link quality estimation and improved collision avoidance properties. Depending on the chosen power level which can be higher or lower than the nominal transmission power level of the data transmission and a repetition coding depending on the chosen power level, a number of different possibilities to improve the connection between the participating stations are proposed and claimed.

公开(公告)号：AT230891T

公开(公告)日：2003-01-15

申请号：AT99928152

申请日：1999-07-01

Applicant: IBM

Inventor： HASSNER MARTIN AURELIANO ,  HEISE NYLES ,  HIRT WALTER ,  TRAGER BARRY MARSHALL

IPC: G11B20/14 ,  G11B20/10 ,  H03M5/14 ,  H03M7/00 ,  H03M7/14 ,  H03M13/00

Abstract: A method and means for reducing high-duty-cycle unconstrained binary signal sequences in storage and communications processes and systems by invertibly mapping such sequences into a (1, k) rate ⅔ RLL codestream constrained to a duty cycle substantially approximating one-third. That is, binary sequences ordinarily mapping into high-duty-cycle RLL-code sequences are either inhibited from repeating indefinitely or excluded.

公开(公告)号：HU0102778A2

公开(公告)日：2001-12-28

申请号：HU0102778

申请日：1999-07-01

Applicant: IBM

Inventor： HASSNER MARTIN AURELIANO ,  HEISE NYLES ,  HIRT WALTER ,  TRAGER BARRY MARSHALL

IPC: G11B20/10 ,  G11B20/14 ,  H03M5/14 ,  H03M7/00 ,  H03M7/14 ,  H03M13/00

Abstract: A method and means for reducing high-duty-cycle unconstrained binary signal sequences in storage and communications processes and systems by invertibly mapping such sequences into a (1, k) rate ⅔ RLL codestream constrained to a duty cycle substantially approximating one-third. That is, binary sequences ordinarily mapping into high-duty-cycle RLL-code sequences are either inhibited from repeating indefinitely or excluded.

公开(公告)号：HU0101092A2

公开(公告)日：2001-07-30

申请号：HU0101092

申请日：1999-04-21

Applicant: IBM

Inventor： GFELLER FRITZ ,  HIRT WALTER ,  INGHAM BRIAN R

IPC: H04B10/11 ,  H04L25/02 ,  H04B10/10

Abstract: The present invention provides an apparatus and a method for improved connectivity in wireless optical networks. Therefore at least two or more receiving units are used which receive an infrared signal and convert it to a digital signal. The digital signals represent data in the form of frames whereby each frame comprises at least a data field and a header field containing a preamble. A selector determines a measure related to the signal-to-noise ratio of the preamble and compares the measures in order to select the best suited signal for further processing.

公开(公告)号：CZ2001107A3

公开(公告)日：2001-05-16

申请号：CZ2001107

申请日：1999-07-01

Applicant: IBM

Inventor： HASSNER MARTIN AURELIANO ,  HEISE NYLEST ,  HIRT WALTER ,  TRAGER BARRY MARSHALL

IPC: G11B20/14 ,  H03M5/14

公开(公告)号：CA2241937A1

公开(公告)日：1997-07-17

申请号：CA2241937

申请日：1996-01-03

Applicant: IBM

Inventor： GFELLER FRITZ RUDOLF ,  DE LANGE MARTIN ,  HIRT WALTER

IPC: H04B10/114 ,  H04L1/00 ,  H04L7/04 ,  H04L12/28 ,  H04B10/04 ,  H04B10/06 ,  H04B10/10

Abstract: Disclosed is an optical communication system enabling communication between several co-existing transmitting and receiving stations. In order to allow communication between the co-existing stations, a robust physical layer header (RPLH; 50) is employed which can be understood by all participating stations. This robust header (50) at least comprises a preamble (52) consisting of frames forming a periodic sequence of pulses, the number of slots per frame and the frame content being known to all participating stations. The preamble (52) serves for relative synchronization and carrier detection of the receiving stations. The robust header (50) further comprises a unique synchronization word (53) used for absolute synchronization of the receiving stations. This synchronization word (53) is followed by a control field (59) of fixed length and known structure. By means of this control field (59) the receiving stations are informed which modulation method will be used for the transmission of data. Under certain circumstances it is also useful to provide other control information in said control field (59) for communication link and network control. Furthermore, information may be exchanged to allow negotiation and/or adaptation of the data rate used for transmission. This allows to optimize the throughput depending on the conditions (quality) on the channel.