Radio frequency local area network

• US 5,394,436 A
• Filed: 06/08/1994
• Issued: 02/28/1995
• 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., Mahany, Ronald L., Luse, Ronald E.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/255,848
• Time in Patent Office: 265 Days
• Field of Search: 370/85.3, 370/93, 370/94.2, 370/94.3, 375/1, 380/34
• US Class Current: 375/132
• 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: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0014 by adapting the source coding
• 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 48/08 : Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/0216 : using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 : where the power saving management affects multiple terminals
• 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 88/14 : Backbone network devices
• CPC Class Codes: H04W 92/20 : between access points
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

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. An RF multi-hop data communication network comprising:

a plurality of mobile terminal nodes;

a plurality of bridging nodes which dynamically create and revise communication pathways between any two nodes in the network;

each of the bridging nodes independently storing and maintaining local information that specifies how communication packets received should flow through that bridging node toward a destination node;

said plurality of bridging nodes, together, forming a spanning tree which specifies the communication pathways in the RF multi-hop communication network; and

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

2. The RF multi-hop data communication system of claim 1 wherein said bridging nodes using HELLO message_-- broadcasts to create and maintain the local information.

3. The RF multi-hop data communication system of claim 2 further comprising means for calculating the time at which subsequent HELLO message broadcasts are scheduled to be received, permitting nodes which receive the HELLO message broadcasts to enter a power conserving mode until a subsequent HELLO message broadcast is scheduled.

4. The RF multi-hop data communication system of claim 3 comprising means for offsetting the time of subsequent HELLO message broadcasts, said means for offsetting using a first pseudo-random number generator for generating an offset.

5. The RF multi-hop data communication system of claim 4 wherein said means for calculating further comprising a second pseudo-random number generator for computing the offset.

6. The RF multi-hop data communication system of claim 5 further comprising means for passing a seed value between said means for offsetting and said means for calculating so as to synchronize said first and second pseudo-random number generators.

7. An RF multi-hop data communication system comprising:

a plurality of terminal nodes;

a plurality of bridging nodes;

said bridging nodes comprising means for maintaining communication pathways between any two nodes in the network by repeatedly broadcasting messages identifying itself; and

said terminal nodes comprising means for determining the timing between the identifying message broadcasts to be received from the bridging nodes, permitting said terminal nodes to enter a power conserving mode until subsequent identifying message broadcasts are scheduled.

8. The RF multi-hop data communication system of claim 7 wherein said means for maintaining communication pathways utilizes a spanning tree configuration, and wherein said terminal nodes further comprising means for calculating the time period between identifying message broadcasts to be received.

9. The RF multi-hop data communication system of claim 8 wherein the means for determining the timing and the means for calculating the time both further comprise pseudo-random number generator using a common seed value.

10. The RF multi-hop data communication system of claim 9 further comprising means for passing a seed value between said means for determining the timing and the means for calculating the time.

11. In a multi-hop data communication network having a plurality of bridging nodes, a plurality of terminal nodes comprising:

an RF transceiver;

means for segmenting digitally encoded data to be transferred into discrete data packets;

means responsive to said segmenting means for individually transmitting each discrete data packet; and

means for reconstructing discrete data packets into digitally encoded data.

12. The multi-hop data communication network of claim 11 wherein said terminal nodes further comprise means for digitally encoding voice signals, and means for generating audio signals from digitally encoded voice signals.

13. The multi-hop data communication network of claim 11 wherein the length of each of said discrete data packets is chosen based on correlation distance.

14. The multi-hop data communication network of claim 12 wherein the length of each of said discrete data packets is chosen based on correlation distance.

15. The multi-hop data communication network of claim 11 wherein the plurality of bridging nodes, together, forming a spanning tree which specifies communication pathways in the multi-hop communication network.

16. The multi-hop data communication network of claim 15 wherein said terminal nodes further comprise means for digitally encoding voice signals, and means for generating audio signals from digitally encoded voice signals.

17. The multi-hop data communication network of claim 16 wherein the length of said discrete data packets is chosen based on correlation distance.

18. An RF multi-hop data communication network comprising:

a root node;

a plurality of bridging nodes;

a destination terminal node;

a mobile, source terminal node which selects bridging nodes to receive RF data packet transmissions destined for said destination terminal node;

said root node and each bridging node having a spanning tree, routing table that lists an address for each node that constitutes a next hop toward an upstream node; and

each of said plurality of bridging nodes selecting a next hop address from its routing table in response to an RF data packet received, and transmitting the next hop address along with the RF data packet.

19. The RF multi-hop data communication network of claim 18 wherein said source terminal node comprising means for segmenting a data unit into data packets, and means for sequentially transmitting each data packet.

20. The RF multi-hop data communication network of claim 19 wherein said destination terminal node comprising means for reconstructing received data packets into the data unit.

21. The RF multi-hop data communication network of claim 19 wherein the length of each of the data packets is chosen based on correlation distance.