Method for maintaining a communication link in wireless network groups

• US 8,041,359 B1
• Filed: 08/02/1999
• Issued: 10/18/2011
• Est. Priority Date: 08/02/1999
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Pittampalli, Eshwar
• Primary Examiner(s): PHUONG, DAI
• Application Number:
  US09/365,678
• Time in Patent Office: 4,460 Days
• Field of Search: 455/454, 455/435, 455/439, 455/432, 455/426, 455/447, 455/435.1, 455/436, 455/451, 455/452.1, 455/452.2, 455/444, 455/450, 375/132, 375/134
• US Class Current: 455/444
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Disclosed herein is a method and apparatus for maintaining communication between a dependent and a communications network when the dependent is outside a coverage area associated with its master using a controller and a communications network. In one embodiment, when the dependent is in a piconet, the dependent is within communication range of its master using a communication channel on frequency band f_band(1). When the dependent moves outside the piconet, the dependent should be within communication range of the controller and, thus, switches to another communication channel within frequency band f_band(1) such that it may communicate with the controller. When the dependent moves outside the communication range of the controller, the dependent should be within communication range of a communications network or a base station and, thus, switches to a communication channel within another frequency band f_band(2).

Claims

1. A method of maintaining a communication link in a communication network comprising:

initiating, via a master device, unregistration at a controller having a first wireless coverage area, the unregistration being of a dependent in communication with the master device using a communication channel on a frequency band f_band(1); and

transmitting a first message, wirelessly using a frequency f_band(2), from the controller to the dependent indicating to the dependent to register with a network element having a second wireless coverage area, the first wireless coverage area being within the second wireless coverage area, the network element being at a higher level than the master device in a hierarchy of the communication network; and

transmitting a second message, wirelessly using the frequency f_band(2), from the controller to the network element indicating to the network element to start communicating with the dependent,

wherein the dependent is unregistered based on an unregistration message sent to the controller from the master device when the signal strength of a signal transmitted between the dependent and the master device falls below a threshold value, the signal strength being measured at the master device.

2. The method of claim 1 comprising the additional steps of:

receiving a registration message from the master device on the frequency band f_band(1) indicating the dependent; and

registering the dependent with the master device before the step of unregistering.

3. The method of claim 1 comprising the additional step of:

transmitting another message indicating to the network element to register the dependent with the network element via the controller.

4. The method of claim 1, wherein the dependent is unregistered when an unregistration message is received.

5. The method of claim 1, wherein the dependent is unregistered when a strength of a signal transmitted between the dependent and the master device on the frequency band f_band(1) falls below a threshold value.

6. The method of claim 5 comprising the additional step of:

monitoring a communication channel associated with the master device on the frequency band f_band(1).

7. The method of claim 6, wherein the communication channel is defined by a frequency hopping sequence.

8. The method of claim 1, wherein the message is transmitted using a frequency band f_band(2).

9. The method of claim 1 comprising the additional step of:

transmitting a handoff message to the network element indicating to the network element to communicate directly with the dependent.

10. The method of claim 9, wherein the handoff message is transmitted on the frequency band f_band(2).

11. A method for maintaining a communication link in a communication network comprising:

receiving a first registration message at a first master device from a dependent over a first frequency hopping sequence associated with the master device, the first master device having a first wireless coverage area;

transmitting a second registration message from the first master device over a second frequency hopping sequence associated with a second master device having a second wireless coverage area, the first wireless coverage area being within the second wireless coverage area, the second master device being at a higher level than the first master device in a hierarchy of the communication network;

monitoring a strength at the first master device for a signal transmitted by the dependent over the first frequency hopping sequence; and

transmitting an unregistration message over the second frequency hopping from the first master device to the second master device sequence if the strength of the signal transmitted over the first frequency hopping sequence falls below a threshold value.

12. The method of claim 11, wherein the first and second frequency hopping sequences are part of a set of frequency hopping sequences on a same frequency band.