Simple wireless network with store and forward methods incorporating anti-looping codes

• US 6,594,272 B1
• Filed: 11/23/1999
• Issued: 07/15/2003
• Est. Priority Date: 11/23/1999
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Shupe, Allen, Ketcham, Carl, Whitney, Nathan
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US09/447,281
• Time in Patent Office: 1,330 Days
• Field of Search: 370/229, 370/230, 370/231, 370/235, 370/236, 370/310, 370/312, 370/351, 370/389, 370/390, 370/392, 370/393, 370/400, 370/428, 370/429, 370/432, 370/445, 370/447, 370/448, 709/238, 709/242, 709/243, 709/244
• US Class Current: 370/428
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A plurality of wireless nodes in a network, such as elements of a residential or office home computer system, security system, HVAC or sprinkler system, or the like, communicate with each other over a radio frequency channel. A node generates a packet and transmits it to all the other nodes within range. All the receiving nodes in turn retransmit the packet to all the nodes within range of them. This process floods the network with packets, insuring that all of the nodes at the site receive the packet. The packet contains a de-looping code that is processed by all the nodes that receive the packet. The de-looping code insures that the packet is broadcast by any given node only once. Collisions resulting from multiple nodes simultaneously trying to gain access to the RF medium is avoided by implementing an exponential backoff algorithm, by which all the nodes wait for a random period of time before attempting transmission on the medium. The nodes may communicate with higher level logical domains by virtue of selected nodes functioning as bridges to higher domains. The higher level domains can include neighborhood, regional, or global networks, including global IP-based cabled networks.

Claims

1. A method of networking a plurality of wireless nodes, said nodes organized into a logical domain, comprising the steps of:

(a) generating a packet in a first node and broadcasting said packet to one or more nodes that are in range of said first node, said packet comprising a field containing an anti-looping code;

(b) receiving said packet in a second node in range of said first node, said second node re-transmitting said packet to additional nodes, including a third node, in said domain that are within range of said second node;

(c) processing said anti-looping code to ensure that said packet is broadcast a single time; and

(d) broadcasting said packet from said third node to additional nodes in said logical domain until all nodes in said domain have received said packet, each of said third and additional nodes in said domain processing said anti-looping code to thereby ensure that each of said third and additional nodes rebroadcasts said packet only a single time.

2. The method of claim 1, wherein said nodes are organized within a network comprising multiple hierarchical domains, and wherein said packet further comprises a field containing information identifying a domain type, said domain type indicating the highest domain to which said packet is to be broadcast.

3. The method of claim 1, wherein said packet further comprises a field containing information uniquely identifying nodes in a logical sub-network, such that any nodes receiving said packet which are not members of said logical sub-network do not respond to said packet.

4. The method of claim 1, wherein said packet further comprises a field containing information uniquely identifying nodes in a site, such that any nodes receiving said packet which are not located at said site do not respond to said packet.

5. The method of claim 1, wherein said method is implemented by wireless nodes in an office building.

6. The method of claim 1, wherein said wireless nodes comprise elements of a security system.

7. The method of claim 1, wherein said wireless nodes comprise elements of a HVAC system.

8. The method of claim 1, wherein said method is implemented by wireless nodes in a warehouse.

9. The method of claim 1, wherein said method is implemented by wireless nodes in a residence.

10. The method of claim 1, wherein said wireless nodes include a general purpose computer.

11. The method of claim 1, wherein said wireless nodes comprise nodes of a sprinkler system.

12. A method of networking a plurality of wireless nodes, said nodes organized into a logical domain, comprising the steps of:

generating a packet in a first node in said plurality of wireless nodes;

broadcasting said packet from said first node to other nodes within range of said first node;

repeatedly broadcasting said packet until each of said plurality of wireless nodes in said logical domain have received said packet;

wherein said packet contains an anti-looping code wherein each of said nodes that receives a broadcast of said packet from another of said nodes processes said anti-looping code and thereby only broadcasts said packet a single time.

13. The method of claim 12, wherein each of said nodes gain access to an RF network linking said nodes together to broadcast said packet according to the following procedure:

(a) detecting an existing transmission on said RF channel, and responsively disabling-transmission of said node on said RF network;

(b) detecting a termination of said existing transmission; and

(c) initiating transmission on said RF channel after waiting a random period of time after said termination of said existing transmission has been detected.

14. A node of a wireless network, comprising a software program generating a packet for broadcast to other nodes in said network, said packet having a structure comprising:

a field containing a de-looping code, said de-looping code comprising a series of bits, wherein each node in said wireless network is assigned a unique de-looping code; and

a field containing a packet sequence number;

said software program further comprising instructions processing said de-looping code and said packet sequence number to determine whether said de-looping code and packet sequence number match a packet sequence number and de-looping code of a previous packet broadcast by said node, and wherein said packet is transmitted to other nodes in said network if a match does not exist.

15. The node of claim 14, wherein said node implements an exponential back-off algorithm before transmitting said packet if a current transmission is detected.

16. The node of claim 14, wherein said packet structure further comprises one or more reserved fields.

17. The node of claim 14, wherein said packet further comprises a subnet identification field.

18. The node of claim 14, wherein said packet further comprises a destination domain field.