Redundant radio frequency network having a roaming terminal communication protocol

• US 20040169583A1
• Filed: 01/22/2004
• Published: 09/02/2004
• Est. Priority Date: 05/13/1991
• Status: Active Grant

• Current Assignee: Innovatio IP Ventures LLC
• Original Assignee: Robert C. Meier
• Inventors: Meier, Robert C.
• Granted Patent: US 7,386,002 B2
• Time in Patent Office: Days
• US Class Current: 340/5.31
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• 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 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 40/04 based on wireless node resources
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/30 for proactive routing
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A redundant network and communication protocol is disclosed having host computers, RF base stations and roaming terminals. In one embodiment, this network utilizes a polling communication protocol which, under heavy loaded conditions, requires that a roaming terminal wishing to initiate communication must first determine that the channel is truly clear by listing for an entire interpoll gap time. Thus, when a “hidden” terminal is communicating, the roaming terminal can conclude that such communication is taking place upon receiving a polling frame directed to that “hidden” terminal from the normally silent base station. In a further embodiment, a criterion used by the roaming terminals for attaching to a given base station reduces conflicts in the overlapping RF regions of adjacent base stations. Also, in another embodiment, inherent redundancy techniques are used with a spanning tree approach for determining the most efficient pathways from a source to a destination for ensuring that the network adapts to spatial changes or break downs within the network.

Claims

1. A method of beginning a data exchange over an RF communication link between a polling device and a sending device wherein the polling device has an interpoll gap time, the method comprising:

(a) identifying by the sending device that the RF communication link is clear throughout a period which is at least as long as the maximum possible interpoll gap time under conditions solely when the RF communication link is heavily loaded; and

(b) transmitting a request for poll frame by the sending device.

2. The method of claim 1 which comprises, before (a), a further act of branching to (b) if traffic on the wireless communication channel is below a predetermined level.

3. The method of claim 1 wherein the interpoll gap is a predetermined time period of fixed duration between consecutive poll frames.

4. The method of claim 1 wherein, in (a), if the beginning of the period coincides with a detected end of transmission, attempting to avoid collisions by delaying a random period before executing (b).

5. The method of claim 2 wherein, in (a), if the traffic is below the predetermined level, branching to (b) only when the sending device does not sense a carrier on the RF communication channel.

6. A method of beginning a data exchange over a wireless communication channel between a destination device and a sending device comprising:

waiting, by the sending device, a period of time that is at least as long as a predetermined time period and detecting no communication on the wireless communication channel;

attempting, by the sending device, to initiate communication to the destination device; and

if the attempt to initiate communication to the destination device proves successful, transmitting, by the sending device, a series of packets wherein each two consecutive packet transmissions are separated by no more than the predetermined time period.

7. The method of claim 6 wherein the destination device comprises a polling device.

8. The method of claim 6 wherein if the beginning of the period of time during which no communication is detected coincides with the end of a detected transmission, attempting to avoid collisions by delaying a random period before attempting to initiate communication to the destination device.

9. The method of claim 6 which comprises immediately attempting to initiate communication to the destination device if traffic on the wireless communication channel is below a predetermined level.

10. The method of claim 6 which comprises immediately attempting to initiate communication to the destination device when the sending device does not sense activity on the wireless communication channel, if traffic on the wireless communication channel is below a predetermined level.

11. A method of beginning a data exchange over a wireless communication channel between a destination device and a sending device comprising:

selecting a predetermined traffic level over the wireless communication channel;

determining that the traffic is below the predetermined traffic level;

transmitting a request for a poll frame by the sending device.

12. The method of claim 11 wherein the destination device comprises a polling device.

13. The method of claim 11 wherein after determining that the traffic is below the predetermined traffic level, transmitting a request for a poll frame only when the sending device does not sense a carrier on the wireless communication channel.

14. A method of beginning communication within a wireless communication network among a plurality of devices comprising:

determining whether communication is being performed from a first device of the plurality of devices to a second device of the plurality of device, the communication being performed on a communication channel within the wireless communication network;

initiating communication between the first device and the second device after determining that no communication is being performed; and

continuing the communication when the communication proves successful.

15. The method of claim 14 further comprising determining a level of communication that is being performed from the first device to the second device.

16. The method of claim 15 further comprising waiting a predetermined period of time before initiating communication when the level exceeds a predetermined threshold.

17. The method of claim 14 wherein the first device comprises a sending device.

18. The method of claim 14 wherein the second device comprises a receiving device.

19. The method of claim 14 wherein at least one of the first device and the second device comprises a polling device.

20. The method of claim 14 further comprising transmitting a request for poll frame by at least one of the first device and the second device.