International Business Machines Corporation

Ibm Canada Limited - Ibm Canada Limitee

Danny N McKay

Mahmoud Naghshineh

Parviz Kermani

Babak Rezvani

Claus Michael Olsen

Peter Dirk Hortensius

Peter E Reissner

Lee F Hartley

Fritz R Gfeller

Frank P Novak

Roger Y Cheung

Murray C Baker

Patrick K Kam

Nelson Jean

Daniel Y Wong

Rupam Sinha

Roger Y M Cheung

The invention provides a method for communication between a plurality of stations in a communication network using media access protocol, in which medium access is granted to stations obtaining a successful reservation of the medium and in which data transmission verification is performed by the protocol within the reservation. In the method a station sends a request message on the communication medium for a reservation of the medium to a recipient station in the network. The recipient station sends a reservation confirmation message back to the sending station which receives it and responds to the reservation confirmation message by sending an ordered sequence of data frames to the recipient station. After sending the ordered sequence of data frames the sending station sends an end of transmission message to the recipient station, which replies by sending back an end of transmission confirmation identifying the number of frames received in their original sequence. If the number is not correct remedial action can be taken by the sending station to resend missing data. Address conflict resolution is also provided by another aspect of the invention. The invention has embodiments which handle unicast and groupcasting transmissions.

Data link layer extensions to a high latency wireless MAC protocol

An internetworking node for providing internetworking services for mobile wireless nodes is disclosed. Each mobile wireless node is associated with at the most one internetworking node. Each mobile wireless node selects which internetworking node it will associate with. The internetworking node will then act for all wireless nodes associated to it in relaying messages between wireless nodes or between a wired lane and the wireless nodes.

Method and apparatus for connecting a wireless LAN to a wired LAN

A Carrier Sense Multiple Access with Automatic Abort collision avoidance (CSMA/AA) controller for application in a wireless local area network (LAN). The CSMA/AA controller reduces the number of invalid states arising from collision conditions on the communication channel. The controller features hardware logic control for time critical functions. The hardware logic circuit detects events and fault conditions under the CSMA reservation protocol which may otherwise be missed by the Medium Access Control software layer and aborts the transmit procedure. The off-loading of time critical functions also improves the performance of the system and reduces the variability arising from overhead execution times associated with the system CPU.

Carrier sense collision avoidance with auto abort

An internetworking node for providing internetworking services for mobile wireless nodes. Each mobile wireless node is associated with at the most one internetworking node. Each mobile wireless node selects which internetworking node it will associate with. The internetworking node will then act for all wireless nodes associated to it in relaying messages between wireless nodes or between a wired Local Area Network (LAN) and the wireless nodes.

The throughput of a Request-to-Send and Clear-to-Send (RTS/CTS) based distributed media access control protocol is improved by reserving the medium in a hierarchical fashion. The shared medium is reserved for two stations called the participants. During the reserved period, a master (or primary) attribute and a slave (or secondary) attribute are given to the participants and the medium is shared between them using any suitable coordination algorithm. 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 be exchanged. In the case that a role exchange takes place, 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. Observing stations which are not participating in the reservation can be invited to join the reservation as additional secondary stations if this does not cause any interference to any other existing reservations. The efficiency of the medium reservation may be improved also by piggy-backing any reservation specific signals onto data packets and by defining new response frames such as Hold-to-Send (HTS) and Free-to-Send (FTS) for flow control when there is a congested receiving station.

Extensions to distributed MAC protocols with collision avoidance using

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.

Media access control protocols in a wireless communication network

A method of delievering data in a wireless communications network using a combination of collision sensing and collision avoiidance protocols. More precisely, if there are no hidden nodes detected in the network, a collision sensing protocol is used; however, if there are hidden nodes, then a collision avoidance protocol is used. This invention also deals with methods of determining the presence or absence of hidden nodes.

Growing community of inventors

Toronto, Canada

Danny N McKay