Ad hoc initialization for wireless local area network

• US 5,729,680 A
• Filed: 05/11/1995
• Issued: 03/17/1998
• Est. Priority Date: 06/25/1993
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: Netwave Technologies Limited
• Inventors: Rosen, David B., Belanger, Philip H., Baugh, William N.
• Primary Examiner(s): DINH, DUNG C
• Application Number:
  US08/439,337
• Time in Patent Office: 1,041 Days
• Field of Search: 375/356, 375/202, 375/200, 395/200.19, 395/200.1, 395/200.11, 370/254, 370/255, 370/431, 370/436, 370/437
• US Class Current: 709/222
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/71563 Acquisition
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 36/00 Hand-off or reselection arrangements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• 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 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless network is initialized by communications between mobile units forming an ad hoc network or by communications between a mobile unit and an access point unit. Mobile units transmit announcements in order to establish a communication link. To ensure the announcements are received, the mobile units scan different frequencies at various times using various hop sequences. Once communication is established, one mobile unit adopts the hop frequency of the other mobile unit according to a comparison between the hop frequencies of the two units. Multiple mobile units initialize to form ad hoc networks in similar manner.

Claims

1. A method of initializing a wireless area network, comprising the step of:

using a hop number of a current hop period of a first unit to determine whether said first unit scans or transmits during a portion of said current hop period, said current hop period being one of a sequence of hop periods, each of said hop periods of said sequence having a different hop number.

2. The method of claim 1, further comprising the step of:

scanning one frequency during said portion for an amount of time X, and transmitting at least once every amount of time X when in said current hop period but not in said portion of said current hop period.

3. The method of claim 1, further comprising the step of:

scanning multiple frequencies during said portion of said current hop period, each frequency being scanned for a time X.

4. The method of claim 1, further comprising the step of:

before said using step, scanning for a transmission sent by a unit connected by wire to the area network.

5. The method of claim 1, further comprising the step of:

after said using step, receiving a transmission having a field indicative of a sequence of hop periods used by a second unit and having a field indicative of an amount of time remaining in a current hop period of said second unit.

6. The method of claim 5, said current hop period of said second unit corresponding to a current hop number, further comprising the step of:

after said receiving step, determining whether to adopt said current hop number of said second unit or to retain said current hop number of said first unit by comparing said hop number of said current hop period of said first unit with said current hop number of said current hop period of said second unit.

7. The method of claim 6, wherein:

the hop number adopted or retained by said first unit is the hop number having the greatest hop number when the absolute value of said hop number of said current hop period of said second unit minus said hop number of said current hop period of said first unit is less than the total number of hops in said sequence of hops minus the absolute value of said hop number of the current hop period of said second unit minus said hop number of said current hop period of said first unit, wherein otherwise the hop number adopted or retained is the smallest hop number.

8. The method of claim 6, wherein:

the hop number adopted or retained by said first unit is the hop number having the smallest hop number when the absolute value of said hop number of said current hop period of said second unit minus said hop number of said current hop period of said first unit is less than the total number of hops in said sequence of hops minus the absolute value of said hop number of the current hop period of said second unit minus said hop number of said current hop period of said first unit, wherein otherwise the hop number adopted or retained is the greatest hop number.

9. A wireless mobile unit comprising a connector for coupling to a computer bus, a digital portion, and a radio transmitter/receiver circuit portion, said wireless mobile unit not being in communication with any local area network, a plurality of hop periods comprising a sequence of hop periods, said wireless mobile unit scanning during portions of selected ones of said sequence of hop periods and transmitting during others of said sequence of hop periods, said wireless mobile unit periodically transmitting during each of said plurality of hop periods of said sequence when said wireless mobile unit is not scanning.

10. The wireless mobile unit of claim 9, wherein said digital portion comprises means for determining whether to scan or transmit during each hop period of said sequence of hop periods.

11. The wireless mobile unit of claim 10, wherein said digital portion comprises means for determining whether or not to adopt a hop number of another wireless mobile unit.

12. The wireless mobile unit of claim 11, wherein said digital portion comprises means for determining whether or not to synchronize in time to a hop tick of another wireless mobile unit.

13. A method of initializing a wireless area network having a plurality of units, comprising the steps of:

using a hop number of a current hop period of a first unit to determine whether or not said first unit scans during a portion of said current hop period, said current hop period being one of a sequence of hop periods, each of said hop periods of said sequence having a different hop number;

receiving a transmission having a field indicative of a sequence of hop periods used by a second unit and having a field indicative of an amount of time remaining in a current hop period of said second unit; and

determining whether to adopt said current hop number of said second unit or to retain said current hop number of said first unit, wherein the hop number adopted or retained by said first unit is the hop number having the greatest hop number when the absolute value of said hop number of said current hop period of said second unit minus said hop number of said current hop period of said first unit is less than the total number of hops in said sequence of hops minus the absolute value of said hop number of the current hop period of said second unit minus said hop number of said current hop period of said first unit, wherein otherwise the hop number adopted or retained is the smallest hop number.

14. A method of initializing a wireless area network having a plurality of units, comprising the steps of:

using a hop number of a current hop period of a first unit to determine whether or not said first unit scans during a portion of said current hop period, said current hop period being one of a sequence of hop periods, each of said hop periods of said sequence having a different hop number;

receiving a transmission having a field indicative of a sequence of hop periods used by a second unit and having a field indicative of an amount of time remaining in a current hop period of said second unit; and

determining whether to adopt said current hop number of said second unit or to retain said current hop number of said first unit, wherein the hop number adopted or retained by said first unit is the hop number having the smallest hop number when the absolute value of said hop number of said current hop period of said second unit minus said hop number of said current hop period of said first unit is less than the total number of hops in said sequence of hops minus the absolute value of said hop number of the current hop period of said second unit minus said hop number of said current hop period of said first unit, wherein otherwise the hop number adopted or retained is the greatest hop number.

15. A mobile unit for a wireless area network, comprising:

a connector for coupling to a computer bus;

a logic portion coupled to the connector; and

a radio transmitter/receiver coupled to the logic portion;

wherein the logic portion defines a sequence of hop periods, and when said mobile unit is not in communication with the wireless area network, the radio transmitter/receiver scans during portions of selected hop periods and transmits during other portions of said hop periods when it is not scanning.