Transmit power control for mobile unit

• US 20070004444A1
• Filed: 09/07/2006
• Published: 01/04/2007
• Est. Priority Date: 11/28/2001
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Klein, John, Melville, Graham, Kellogg, William, Werback, Andrew, Montgomery, Richard, Ouchida, Wayne, Nguyen, Dong
• Granted Patent: US 7,720,500 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/08 Closed loop power control

Abstract

In a wireless local area network which includes access point having variable transmitter power levels, transmitter power data is sent from the access points to the mobile units and used by the mobile units in order to provide a corresponding variation in the transmitter power of the mobile unit.

Claims

1. In a wireless local area network wherein mobile units receive beacon signals from access points having varying transmitter power levels and associate with access points for data communications therewith, a method for controlling transmitter power level of a mobile unit, comprising:

transmitting from an access point to said mobile unit beacon signals that also include data representing transmitter power level of said access point in operation;

receiving at said mobile unit data representing transmitter power level of said access point in operation; and

adjusting transmitter power level of said mobile unit in accordance with data representing transmitter power level of said access point in operation included in said beacon signals.

2. A method according to claim 1 wherein adjusting power level of said mobile unit comprises setting said mobile unit to a power level corresponding to said access point transmitter power level data.

3. A method according to claim 1 wherein said adjusting power level of said mobile unit is performed when said mobile unit associates with an access point.

4. A mobile unit for use in a wireless local area network having access points transmitting at different power levels, comprising:

a receiver for receiving data signals including beacon signals from said access points;

a transmitter responsive to access point power level signals to transmit at a selected transmitter power level corresponding to said access point power level signals; and

a processor, coupled to process data signals from said receiver and programmed to derive access point power level data included in said beacon signals received from said access points and to provide corresponding transmitter power level signals to said transmitter.

5. A method for controlling interference in a wireless local area network having access points and mobile units, comprising:

providing access points including access points with adjustable transmitter power level and distributing said access points over an area with varying spacing between access points;

adjusting the transmitter power of said adjustable transmitter power level access points according to said access point spacing, wherein access points with greater spacing have greater transmitter power in operation;

providing access points power level data representing transmitter powers of said adjustable power level access points in operation, and transmitting said access points power level data from each of said adjustable power level access points;

providing mobile units having transmitters responsive to power level signals for adjusting transmitter power of said mobile units;

receiving said access points power level data representing transmitter powers of said adjustable power level access points in operation at said mobile units and providing power level signals corresponding thereto to said mobile unit transmitters,

wherein said access points transmit beacon signals for use by mobile units to associate with one of said access points, and wherein said access points power level data representing transmitter powers of said adjustable power level access points in operation is transmitted within said beacon signals.

6. The method according to claim 5 wherein providing power level signals corresponding thereto to said mobile unit transmitters comprises providing a power level signal to a mobile unit transmitter while a mobile unit is associating with an access point.