Power saving frame transmission method

• US 20060171341A1
• Filed: 01/31/2005
• Published: 08/03/2006
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Wang, Huayan Amy, Sakoda, William
• Granted Patent: US 7,477,616 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method that enables the power saving frame transmission comprising an AP informing a plurality of stations within its range in a WLAN about a plurality of scheduled service periods during which the AP has access to a channel in a scheduled service time, receiving the information about the plurality of scheduled service periods by the plurality of stations and deciding about initiating or not initiating a frame transmission, whether or not an acknowledgement and an immediate response expected from other APs pertaining to said WLAN are received prior to a subsequent scheduled service time, wherein the frame is transmitted in a cooperative frame transmission scenario.

Claims

1. A power saving frame transmission method, comprising:

informing a plurality of stations within a range of an AP in a WLAN about a plurality of scheduled service periods during which said AP has access to a channel in a scheduled service time;

receiving said information about said plurality of scheduled service periods by said plurality of stations; and

deciding about initiating or not initiating a frame transmission, weather or not an acknowledgement and an immediate response expected from other stations pertaining to said WLAN are received prior to a subsequent scheduled service time,

wherein said frame is transmitted in a cooperative frame transmission scenario.

2. The power saving frame transmission method of claims 1, wherein said AP communicates with said plurality of stations through dedicated broadcast management frames.

3. The power saving frame transmission method of claims 1, wherein said AP communicates with said plurality of stations through proprietary data frames.

4. The power saving frame transmission method of claims 1, wherein said AP communicates with said plurality of stations through special information elements in relevant 802.11 frames.

5. The power saving frame transmission method of claims 1, wherein said AP communicates with said plurality of stations through special header/trailer fields in relevant 802.11 frames.

6. The power saving frame transmission method of claim 1, further comprising reaching an agreement between said access point and said plurality of stations about service periods.

7. The power saving frame transmission method of claim 1, wherein all said stations in a wireless medium subordinated to said WLAN refrain from transmitting at the beginning of said service period, and wherein said WLAN is idle at the beginning of said service period.

8. The power saving frame transmission method of claim 7, wherein said idle wireless medium allows said AP to gain access to said channel, and said transmission opportunity.

9. A power saving frame transmission method in a WLAN who'"'"'s clients are not all cooperative, comprising:

informing a plurality of stations within a range of an AP in the WLAN about scheduled service periods during which said AP intends to have access to a channel in a scheduled service time;

reaching an agreement about a specific start time of service between a plurality of stations to whom said AP pertains in a wireless medium;

sending a frame according to a cooperative frame transmission scenario if said agreement is reached;

enforcing said scheduled service time by said AP that gains control of the wireless medium ahead of time by sending a CTS frame;

sensing if said wireless medium is busy after gaining control of the wireless medium, and

sending another CTS frame with adjusted duration DIFS after the wireless medium clears,

wherein the AP gains control of the wireless medium one packet time ahead of a next scheduled service time,

wherein said CTS to self frame has a predetermined duration field, and

wherein said AP uses PIFS to immediately gain exclusive access to the wireless medium.

10. The frame transmission method of claim 10, wherein said AP gains control of said wireless medium by sending a CTS-to-self frame with appropriate duration field.