Radio frequency local area network

• US 5,504,746 A
• Filed: 03/27/1995
• Issued: 04/02/1996
• Est. Priority Date: 10/01/1991
• Status: Expired due to Term

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: Meier, Robert C.
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US08/410,592
• Time in Patent Office: 372 Days
• Field of Search: 370/85.12, 370/85.13, 370/85.14, 370/60, 370/60.1, 370/94.1, 370/94.2, 370/95.1, 370/95.3, 379/58, 379/60, 455/53.1, 455/54.1, 455/33.1, 455/56.1
• US Class Current: 370/256
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 15/0225 User interface arrangements, e.g. keyboard, display; Interfaces to other computer systems
• CPC Class Codes: G06K 7/1098 the scanning arrangement having a modular construction
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H01Q 1/241 used in mobile communications, e.g. GSM H01Q1/247, H01Q1/248 take precedence
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04B 1/3833 Hand-held transceivers
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/44 Distributed routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/488 using root node determination
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/325 in the network layer [OSI layer 3], e.g. X.25 H04L69/16 takes precedence
• CPC Class Codes: H04L 69/326 : in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04L 9/40 : Network security protocols
• CPC Class Codes: H04W 40/24 : Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 40/34 : Modification of an existing route
• CPC Class Codes: H04W 84/12 : WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/04 : adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/08 : Access point devices
• CPC Class Codes: H04W 88/14 : Backbone network devices

Abstract

An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.

Claims

1. A multi-hop data communication network having wireless communication capability comprising:

a plurality of mobile terminals;

a plurality of bridges, each of the plurality of bridges and each of the plurality of mobile terminals having a wireless transceiver and comprising a node in the network;

said plurality of bridges dynamically create and revise communication pathways between any two nodes in the network;

each of said plurality of bridges independently store and maintain local information that specifies how communication packets received should flow through that bridge toward a destination node;

said plurality of bridges, together, form a spanning tree which specifies the communication pathways in the multi-hop communication network; and

each of said plurality of bridges adding to each communication packet received the identity of a next node in a communication pathway to the destination node.

2. The multi-hop data communication network of claim 1 wherein, using a backward learning technique, each of said plurality of bridges independently create and maintain locally stored information to specify how communication traffic should flow through that bridge.

3. The multi-hop data communication network of claim 2 further comprising a host computer node.

4. The multi-hop data communication network of claim 2 further comprising a root node that functions as a focal point of the communication network.

5. The multi-hop data communication network of claim 4 wherein each of the plurality of mobile terminals comprising means for connecting to the root node through selected ones of said plurality of bridges.

6. The multi-hop data communication network of claim 4 wherein the plurality of mobile terminals further comprising means for connecting to the root node using a HELLO packet protocol.

7. The multi-hop data communication network of claim 6 wherein spread spectrum communication is used in the transceivers of said plurality of bridges and said plurality of mobile terminals.

8. The multi-hop data communication network of claim 6 wherein the plurality of mobile terminals further comprising means for automatically re-establishing connection to the root node upon detachment.

9. The multi-hop data communication network of claim 4 wherein the plurality of mobile terminals and the root node further comprising means for arranging communicaton pathways to provide a minimum number of hops between the root node and the plurality of terminal nodes without overloading the root node or any of the plurality of terminal nodes.

10. A multi-hop data communication network having wireless communication capability for providing communication pathways comprising:

a first communication node;

a mobile second communication node from which it is desired to transmit communication packets to the first communication node, said second communication node having a wireless transceiver;

a plurality of intermediate communication nodes, each of the plurality of intermediate communication nodes having a wireless transceiver, and said plurality of intermediate communication nodes, together, comprising means for forming communication pathways to relay the communication packets from the second communication node to the first communication node;

said mobile second communication node supplementing each communication packet with routing information to guide that communication packet to a selected one of said plurality of intermediate communication nodes in a communication pathway to the first communication node;

upon receipt of a communication packet, each of said plurality of intermediate communication nodes supplementing the communication packet with routing information to guide the communication packet to said first communication node if said first communication node is with range, else to another of said intermediate nodes in a communication pathway toward said first communication node; and

said intermediate communication nodes dynamically arranging communication pathways to provide a minimum number of intermediate communication nodes needed to complete a communication pathway between the first and second communication nodes without overloading any one intermediate communication node.

11. The multi-hop data communication network of claim 10 wherein the plurality of intermediate communication nodes further comprising means for establishing connection between the first and second communication nodes using a HELLO packet protocol.

12. The multi-hop data communication network of claim 11 wherein the plurality of intermediate communication nodes further comprising means for automatically re-establishing connection between the first and second communication nodes upon detachment.

13. In a multi-hop data communication system having a mobile computer node and a plurality of communication nodes, a method for providing communication among the nodes comprising the steps of:

(a) establishing a communication link in a network for a selected one of the plurality of communication nodes;

(b) indicating from the communication node which has been linked to those of the remaining, unlinked communication nodes that a communication link has been established;

(c) establishing a wireless communication link between the unlinked communication nodes which receive the indication and the linked communication node;

(d) repeating steps (b) and (c) for each communication node which has established a wireless communication link until all of the plurality of communication nodes have been wirelessly linked; and

(e) selectively and wirelessly linking by a mobile computer node to ones of said linked communication nodes as necessary to dynamically maintain communication connectivity with the network as said mobile computer node moves throughout the network.

14. In a multi-hop data communication system having wireless capability, a communication node, a mobile terminal node, and a plurality of intermediate communication nodes, a method for providing communication pathways among the nodes comprising the steps of:

(a) establishing for the communication node a wireless communication link with at least one of the plurality of intermediate communication nodes;

(b) indicating by each of the wirelessly linked intermediate communication nodes that a communication link has been established and providing the hopping distance of that link;

(c) analyzing, by the intermediate communication nodes which receive the indication and by the mobile terminal node if it receives the indication, the indication to determine whether to establish a wireless communication link with the intermediate communication node providing the indication, and, if the analysis so indicates, establishing the wireless communication link;

(d) branching to step (b) if the mobile terminal node has not been linked; and

(e) requesting, by any of the communication nodes which become unlinked, a communication link and branching to step (b).

15. In a multi-hop data communication system having a root node, a plurality of communication nodes, and a plurality of mobile terminal nodes, a method for providing and maintaining communication pathways among the nodes comprising the steps of:

(a) indicating by the root node that communication links may be established;

(b) analyzing, by the communication nodes which receive the indication, the indication to determine whether to establish a communication link with the root node providing the indication, and, if the analysis so indicates, establishing a wireless communication link;

(c) indicating by each of the linked communication nodes the hopping distance of the link to the root node;

(d) analyzing, by the communication nodes which receive the indication, the indication to determine whether to establish a communication link with the linked communication node providing the indication, and, if the analysis so indicates, establishing a wireless communication link;

(e) branching to step (c) until all intermediate communication nodes have been linked; and

(f) requesting, by any of the mobile terminal nodes a wireless communication link with a selected one of the linked intermediate nodes.

16. In a multi-hop data communication system having wireless communication capability, a root node, a plurality of communication nodes, and a plurality of mobile terminal nodes, a method for providing communication pathways among the communication nodes comprising the steps of:

(a) indicating by the root node a readiness to establish communication links;

(b) establishing wireless communication links between the root node and the communication nodes receiving the indication;

(c) indicating by each of the linked communication nodes the number of wireless communication links which have been established and providing the hopping distance of the wireless link to the root node;

(d) analyzing, by the communication nodes which receive the indication from the linked communication nodes, the indication to determine whether to establish a communication link with the linked communication node providing the indication, and, if the analysis so indicates, establishing a wireless communication link;

(e) branching to step (c) until all communication nodes have been linked;

(f) indicating by the linked communication nodes the hopping distance of the link to the root node;

(g) analyzing, by the plurality of mobile terminal nodes, the indications which are received from the linked communication nodes to determine with which linked communication nodes to establish a communication link, and, each mobile terminal node establishing at least one wireless communication link;

(h) requesting, by any of the plurality of mobile terminal nodes which become unlinked, a wireless communication link and branching step (f); and

(i) requesting, by any communication node which becomes unlinked, a communication link and branching to step (c).

17. In a multi-hop data communication system having a plurality of communication nodes and a plurality of mobile terminal nodes, a method for providing communication pathways among the communication nodes comprising the steps of:

(a) selecting one of the communication nodes to be a root node;

(b) indicating by the root node that communication links may be established;

(c) establishing wireless communication links between the root node and the communication nodes receiving the indication;

(d) indicating by each of the linked communication nodes the hopping distance of the link to the root node;

(e) analyzing, by the linked communication nodes which receive each indication from the linked communcation nodes, the indications to determine whether to replace the current communication link with a link to the communication node providing the indication, and, if the analysis so indicates, replacing the communication link;

(f) analyzing, by the unlinked communication nodes which receive each indication from the linked communcation nodes, the indications to determine whether to establish a communication link with the communication node providing the indication, and, if the analysis so indicates, establishing the wireless communication link;

(g) branching to step (c) until all communication nodes have been linked.