Apparatus and method for providing a wireless link between two local area network systems

• US 4,876,742 A
• Filed: 03/23/1987
• Issued: 10/24/1989
• Est. Priority Date: 03/23/1987
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Vacon, Gary, Liu, James J.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): KUNTZ, CURTIS A
• Application Number:
  US07/029,214
• Time in Patent Office: 946 Days
• Field of Search: 455/73, 455/31, 455/32, 455/7, 455/9, 455/14, 455/20, 455/66, 455/39, 455/88, 370/85, 370/89, 370/75, 370/97, 370/60, 370/94, 340/825.5, 340/539
• US Class Current: 455/41.2
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay

Abstract

In a data processing system network, apparatus and method are disclosed for coupling two local area networks by means of a wireless link. Typically, two local area network (LAN) systems are coupled by a bridge device, the bridge device receiving signal groups from each LAN system and selectively forwarding the signal groups to the target LAN system. In the presence of the overlapping (or simultaneous) transmission of signal groups applied to the target LAN system, these signal groups must be reapplied to the target LAN system until a non-overlapping transmission is obtained. In the present invention, when the LAN systems are coupled by a wireless (radiation) link, an interface unit is coupled between each wireless transmitter/detector unit and the associated LAN system. Each interface unit includes a bridge device that provides the system response to the overlapping signal groups.

Claims

1. Apparatus for exchanging signal groups between two local area networks, wherein said signal groups are exchanged through a wireless medium, said apparatus comprising:

a first and a second transmitter/receiver unit for transmitting and detecting radiation propagated across said wireless medium, said first and said second transmitter/receiver units exchanging signal groups therebetween;

a first and a second local area network each including a local bus and local processing components coupled to said local bus, said local processing components applying signals to and receiving signals from said local bus;

a first bridge circuit coupled to said first transmitter/receiver unit and to a first local bus of said first local area network for transferring signal groups therebetween, said first bridge circuit identifying first signal groups on said first local bus to be applied to a processing component of said second local area network and applying said first signal groups to said first transmitter/receiver unit for transmission to said second transmitter/receiver unit; and

a second bridge circuit coupled to said second transmitter/receiver unit and a second local bus of said second local area network for transferring signal groups therebetween, said second bridge identifying second signal groups on said second local bus to be applied to a processing component in said first local area network and applying said second signal groups to said second transmitter/receiver unit for transmission to said first transmitter/receiver unit, wherein said first and said second bridge circuits include apparatus for identifying simultaneous transfer of a first signal group and a second signal group therethrough, an identification of a simultaneous transfer causing a reapplication of said first signal group participating in said simultaneous transfer to said first transmitter/receiver unit and a reapplication of said second signal group participating in said simultaneous transfer to said second transmitter/receiver unit.

2. The apparatus for exchanging signal groups between two local area networks of claim 1 wherein said bridge circuits are circuits used for directly coupling two local area networks.

3. The apparatus for exchanging signal groups between two local area networks of claim 1 wherein each of said local area networks are implemented using Carrier Sense Multiple Access/Collision Detect techniques.

4. The apparatus exchanging signal groups between two local area networks of claim 3 wherein each of said local area networks use the ETHERNET protocols.

5. The apparatus for exchanging signal groups between two local area networks of claim 4 wherein said first and second bridge circuits are implemented with bridge circuits used to couple directly two ETHERNET local area network systems.

6. The apparatus for exchanging signal groups between two local area networks of claim 5 wherein transmission of radiation across said wireless link is implemented using microwave techniques.

7. The apparatus for exchanging signal groups between two local area networks of claim 6 wherein said wireless link has maximum distance between transmitter/receiver units determined by a minimum period for a signal group.

8. The apparatus for exchanging signal groups between two local area networks of claim 1 wherein said apparatus for identifying simultaneous transfer has:

a first signal detection unit producing a first signal during transmission of a first signal group,

a second signal detection unit producing a second signal during reception of a second signal group, and

a signal generator applying a collision signal to an associated bridge circuit in response to said first and said second signal.