Power Saving Function for Wireless LANs: Methods, System and Program Products

• US 20080259836A1
• Filed: 02/13/2008
• Published: 10/23/2008
• Est. Priority Date: 11/07/2001
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: BEACH, Robert
• Granted Patent: US 7,961,660 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless data communication system has a first station or mobile unit is linked to a second station configured as an access unit to support packet communication, voice or data, where the voice packets are transmitted in the Continuously Aware Mode (CAM) mode while other packets are buffered by the access point and held until asked for by the first station when in a Power Saving-Poll (PSP) mode. A monitoring apparatus at the access point monitors all transmitted packets and sorts the packets to the mobile unit according to CAM or PSP mode. Voice packets are sent out immediately to the mobile unit. Other packets are stored at the access point. The packet arrival rate may vary during transmission and due to random packet delays introduced by propagation characteristic and processing apparatus. The packet arrival rate and delays are taken into account by the first station in an algorithm to determine and extend the normal safe period in which the station receiver may be powered off.

Claims

28. The communication apparatus according to claim 20, further comprising:

an arrangement operable to determine the safe period by subtracting a standard deviation of a predetermined number of previous packet arrival intervals from an expected packet arrival interval.

29. The communication apparatus according to claim 28, further comprising:

an arrangement operable to incorporate a radio stabilization time into the safe period.

30. The communication apparatus according to claim 20, wherein the continuous packets include voice packets.

31. A communication apparatus, comprising:

a transmitter for transmitting communication packets to a further communication apparatus;

an arrangement for sorting the communication packets into a first category and a second category;

an arrangement for forwarding the packets of the first category to the transmitter immediately after sorting; and

an arrangement for buffering the packets of the second category until a polling signal requesting the packets of the second category is received from the further communication apparatus.

32. The communication apparatus according to claim 31, wherein:

the packets of the first category include voice packets.

33. The communication apparatus according to claim 31, wherein:

the packets of the second category include non-voice packets.

34. The communication apparatus according to claim 31, wherein the transmitter transmits a beacon signal indicating a presence of buffered packets.

35. The communication apparatus according to claim 31, wherein the sorting is performed based on an IEEE 802.1 priority tag.

36. The communication apparatus according to claim 31, wherein the sorting is performed based on at least one of MAC, IP, UDP, and TCP/IP addressing.

37. A method, comprising:

sorting a plurality of packets into a first category and a second category;

transmitting packets of the first category immediately to a communication apparatus; and

buffering packets of the second category until receiving from the communication apparatus a polling signal.

38. The method according to claim 37, wherein the packets of the first category include voice packets.

39. The method according to claim 37, wherein the packets of the second category include non-voice packets.