Cluster head resignation to improve routing in mobile communication systems

• US 6,493,759 B1
• Filed: 07/24/2000
• Issued: 12/10/2002
• Est. Priority Date: 07/24/2000
• Status: Expired due to Term

• Current Assignee: Raytheon BBN Technlogies Corp. (Rtx Corporation)
• Original Assignee: BBNT Solutions LLC (Rtx Corporation)
• Inventors: Weinstein, Joseph J., Passman, William S., Zavgren, John R., Manning, Keith W., Elliott, Brig Barnum
• Primary Examiner(s): Dinh, Dung C.
• Assistant Examiner(s): LE, HIEU C
• Application Number:
  US09/624,635
• Time in Patent Office: 869 Days
• Field of Search: 709/212-213, 709/216, 709/241, 709/227, 709/201, 455/446-450
• US Class Current: 709/227
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

A communications system for communication among plural stations in a network has stations (CH1, CM2, CM3, CH4, CH5, CM6, CM7) arranged in clusters (1a, 1b, 1c) of communication member stations, each communicating with each other. One of the member stations (CH1, CH4, CH5) is a head station of the cluster. The cluster head stations (CH1, CH4, CH5) communicate with other cluster head stations (CH1, CH4, CH5). A method for configuring the network of stations includes a step of operating at least a first (CH5) and a second (CH4) station of the plural stations as cluster head stations, the first (CH5) and second (CH4) stations forming a communications link. The method also includes a step to resign the first (CH5) station from operating as a cluster head station when a predetermined resignation condition is met. The method also includes a step of maintaining the communication link between the first (CH5) and second (CH4) station as the first station (CH5) transitions from operating as a cluster head station (CH5) to operating as a cluster member station (CM5) of a cluster headed by the second cluster head station (CH4).

Claims

1. A mobile communications station which communicates among a plurality of mobile stations in a network in which stations are arranged in clusters of communication member stations, with one member station in each cluster being a head station for the cluster, each member station communicating with the network through one or more cluster head stations, the cluster head stations communicating with other cluster head stations, the mobile station including a transceiver which transmits signals to and receives signals from mobile stations in the network, said mobile communications station comprising:

a memory having network information stored thereon;

a processor which (i) operates said mobile station as a cluster head station;

(ii) resigns said mobile station form operating as a cluster head station; and

(iii) maintains affiliation with a cluster head neighbor at least during a period in which said mobile station resigns from operating as a cluster head station and commences operating as a cluster member of the cluster head neighbor,

wherein sad processor determines whether said mobile station is a network n-connectivity point, and prevents said mobile station from resigning as a cluster head station when said mobile station is an n-connectivity point,

wherein said processor selects a first neighboring cluster head station to maintain affiliation with while resigning as a cluster head station, and

wherein said processor controls the transceiver to transmit a signal to the selected first cluster head station requesting a status change from a cluster head station to a cluster member station.

2. A mobile communications station according to claim 1, wherein the processor resigns the mobile station from operating as a cluster head station when said mobile communication station receives an acknowledgement from the selected first cluster head station, while said processor maintains a communication link with the first cluster head station.

3. A mobile communications station according to claim 1, wherein said processor selects a second neighbor cluster head station to maintain affiliation with when said mobile station does not receive an acknowledgement from the first neighbor cluster head.

4. In a communication system for communication among plural member stations in a network in which member stations are arranged in clusters of communication member stations with one of the member stations being a cluster head, each member station communicating with the network through at least one affiliated cluster head stations, the cluster head stations communicating with other cluster head stations, a method of operating a communication station comprising the steps of;

operating the communications station as a cluster head station;

resigning the communication station form operating as a cluster head station;

maintaining affiliation with a first neighbor cluster head station while the communications station transitions from operating as a cluster head station to operating as a member station of a cluster headed by the first neighbor cluster head station; and

transmitting a signal to the first neighbor cluster head to announce resignation and to request a status change from a cluster head neighbor to a cluster member station.

5. The method according to claim 4, further comprising the steps of:

resigning the communications station from operating as a cluster head station when the communications station receives an acceptance signal from the first neighbor cluster head station; and

transmitting a signal to at least a second neighbor cluster head station signaling the resignation of said communications station as a cluster head station.

6. In a communications system for communication among plural stations in a network in which stations are arranged in clusters of communication member stations with one of the member stations being a head station of the cluster, the cluster head stations communicating with other cluster head stations, a method for configuring the network of stations includes the steps of:

operating at least a first and a second station of the plural stations as cluster head stations, the first and second stations forming a communications link;

resigning the first station from operating as a cluster head station when a predetermined resignation condition is met;

maintaining the communication link between the first and second station as the first station transitions from operating as a cluster head station to operating as a cluster member station of a cluster headed by the second cluster head station;

transmitting a signal representing an intention of the first station to resign as a cluster head station;

determining whether the first station is a network n-connectivity point;

preventing the first station from resigning as a cluster head station when the first station is a network n-connectivity point; and

transmitting a signal from the first station to the second station to announce resignation and to request a status change from a cluster head neighbor to a cluster member station.

7. The method according to claim 6, further comprising the steps of:

resigning the first station from operating as a cluster head station when the first station receives an acceptance signal from the second station; and

transmitting a signal to at least a third cluster head station of the plural station to signal the resignation of the first station as a cluster head station.