Passive probing for handover in a local area network

• US 6,980,535 B2
• Filed: 08/28/2003
• Issued: 12/27/2005
• Est. Priority Date: 08/28/2003
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bennett, Richard L.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Ho, Chuong
• Application Number:
  US10/650,950
• Publication Number:
  US 20050047371A1
• Time in Patent Office: 852 Days
• Field of Search: 370/338, 370/474, 370/331, 370/332, 455/525, 455/453, 455/500, 455/524, 455/432.1, 455/436, 455/517, 455/561, 709/229
• US Class Current: 370/331
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A WLAN (108) includes a first access point (104) for providing wireless service within a first coverage area, a second access point (106) for providing wireless service within a second coverage area and programmed to transmit probe responses, and a wireless communications unit (102) located within the first coverage area and operating on the wireless service of the first access point (104). The communications unit (102) is programmed to monitor, or passively probe, for the probe responses, or is instructed by the first access point (104) on when to monitor for the probe responses, transmitted by the second access point (106). By executing such passive probing, the communications unit (102) may make handover decisions for switching between the wireless service of the first access point (104) to the wireless service of the second access point (106) based on access point data included in the probe responses.

Claims

1. An access point that is arranged and constructed for providing wireless service to a plurality of wireless communications units in a wireless local area network (WLAN), the access point comprising:

a receiver for receiving input signals from any communications units the access point is providing wireless service for;

a transmitter for transmitting output signals to the any communications units; and

a controller, coupled to and controlling the receiver and the transmitter, for operatively cooperating with the receiver and the transmitter to one of receive first information corresponding to passive probing from an other access point and transmit second information corresponding to passive probing to the other access point.

2. The access point of claim 1, wherein the second information further comprises instructions corresponding to one of a defined time and a response interval at which the other access point is to transmit probe responses to the communications unit.

3. The WLAN access point of claim 1, wherein the controller is further for operatively cooperating with the receiver and the transmitter to control at least one of a defined time and a response interval at which the other access point transmits a probe response when the input signals received by the receiver from a communications unit have decreased below a predetermined quality of service thus indicating a handover condition for wireless service for the wireless communications unit.

4. The WLAN access point of claim 1, wherein the controller and the transmitter cooperatively operate to transmit a probe request to the other access point when one of the controller and the communication unit detects a handover condition.

5. The WLAN access point of claim 1, wherein the controller and the transmitter cooperatively operate to communicate with the other access point via one of a wireless and a wireline connection to send the second information to the other access point when one of the controller and the communications unit detects a handover condition, the second information comprising instructions for a probe response to be transmitted from the other access point.