Wireless terminal management method, base station and wireless terminal management program

• US 20050025081A1
• Filed: 06/28/2004
• Published: 02/03/2005
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Redwood Technologies, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Wakamatsu, Masataka
• Granted Patent: US 7,697,464 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In order to make it possible for almost all of wireless terminals to operate intermittently without generating any conflicts in communication, and thereby, to achieve lower power consumption and transmission/reception of data pertaining to a wireless terminal immediately after a return from its power save state with top priority, mobile stations other than a first mobile station may be put in their power save states, while a return timing from the power save state of each of the mobile stations is intentionally shifted by a base station so as not to overlap in time. In addition, the base station performs polling on a mobile station returned from its power save state is polled with top priority so that transmission/reception of data pertaining to the mobile station is carried out between the mobile station and the base station within a CFP.

Claims

1. A wireless terminal management method in a base station constituting a CSMA wireless communication system together with a wireless terminal group including a plurality of wireless terminals operable intermittently, said method comprising:

a step for collecting power saving periods as periods each for n beacons (where n is generally an integer of two or more), the power saving periods notified from each of wireless terminals operable intermittently at a time of an association;

a step for adjusting a start timing of power saving of each of the wireless terminals in order that a return timing from power save states is not overlapped in time with each other as much as possible in accordance with the power saving period collected at said step for collecting power saving periods;

a step for transiting, in accordance with the start timing of power saving adjusted at said step for adjusting a start timing of power saving, wireless terminals reaching the start timing of power saving to initial power save states; and

a step for transiting data transmission/reception and power save state in which transmission/reception of data is performed with top priority with a wireless terminal at every automatic return thereof from a power save state to transit the wireless terminal to the power save state.

2. The wireless terminal management method according to claim 1, wherein the power saving period collected at said step for collecting power saving periods is determined by each of the wireless terminals operable intermittently in accordance with a transmission bandwidth and transmission delay, both required by an application program, and a beacon period and a rough data transmission quantity per the beacon period, both set by the base station.

3. The wireless terminal management method according to claim 1, wherein transition to the power save state of the wireless terminal after the data transmission/reception on a top priority polling to the wireless terminal returned from the power save state at said step for transiting data transmission/reception and power save state is carried out after receiving permission from the base station.

4. The wireless terminal management method according to claim 1, wherein the start timing of power saving with regard to each of the wireless terminals operable intermittently is adjusted so that there is an interval longer than at least two beacon periods between mutual generation of each return timing at the time of the adjustment of the start timing of power saving at said step for adjusting a start timing of power saving.

5. The wireless terminal management method according to claim 3, wherein, in a beacon frame immediate after the power save state, in a case where re-transmission process of data is produced, or where un-transmitted data exists, a return period is extended and the re-transmission or the transmission/reception of the un-transmitted data is carried out in a next beacon frame.

6. The wireless terminal management method according to claim 1, wherein, upon adjusting the start timing of power saving on a newly entering wireless terminal operable intermittently at said step for adjusting a start timing of power saving, in a case where there is no beacon frame which does not overlap the other return timings in a predetermined number of continuous beacon frames, the start timing of power saving is adjusted so that a beacon frame with a smallest number of overlapping return timings is set to be the return timing.

7. The wireless terminal management method according to claim 2, wherein, upon deciding the power saving period by each of wireless terminals operable intermittently, any one of a preliminarily prepared plurality of kinds of power saving period is selectively decided.

8. The wireless terminal management method according to claim 7, wherein said plurality of kinds of power saving period includes a basic period as a period for n beacons and m-fold periods (where m is an integer of two or more) of the basic period.

9. A base station constituting a CSMA wireless communication system together with a wireless terminal group including a plurality of wireless terminals operable intermittently, said base station comprising:

means for collecting power saving periods as periods each for n beacons (where n is generally an integer of two or more), the power saving periods notified from each of wireless terminals operable intermittently at a time of an association;

means for adjusting a start timing of power saving each of the wireless terminals in order that a return timing from power save states is not overlapped in time with each other as much as possible in accordance with the power saving period collected by said means for collecting power saving periods;

means for transiting, in accordance with the start timing of power saving adjusted by said for adjusting a start timing of power saving, wireless terminals reaching the start timing of power saving to initial power save states; and

means for transiting data transmission/reception and power save state, which performs transmission/reception of data with top priority with a wireless terminal at every automatic return thereof from a power save state to transit the wireless terminal to the power save state.

10. The base station according to claim 9, wherein, upon adjusting the start timing of power saving, said means for adjusting a start timing of power saving adjusts the start timing of power saving with regard to each of the wireless terminals operable intermittently so that there is an interval longer than at least two beacon periods between mutual generation of each return timing.

11. The base station according to claim 9, wherein, upon adjusting the start timing of power saving on a newly entering wireless terminal operable intermittently at said means for adjusting a start timing of power saving, in a case where there is no beacon frame which does not overlap the other return timings in a predetermined number of continuous beacon frames, said means for adjusting a start timing power saving adjusts the start timing of power saving so that a beacon frame with a smallest number of overlapping return timings is set to be the return timing.

12. A wireless terminal management program executed in a base station constituting a CSMA wireless communication system together with a wireless terminal group including a plurality of wireless terminals operable intermittently, said program comprising:

a step for collecting power saving periods as periods each for n beacons (where n is generally an integer of two or more), the power saving periods notified from each of wireless terminals operable intermittently at a time of an association;

a step for adjusting a start timing of power saving of each of the wireless terminals in order that a return timing from power save states is not overlapped in time with each other as much as possible in accordance with the power saving period collected at said step for collecting power saving periods;

a step for transiting, in accordance with the power save start timing adjusted at said step for adjusting a start timing of power saving, wireless terminals reaching the start timing of power saving to initial power save states; and

a step for transiting data transmission/reception and power save state in which transmission/reception of data is performed with top priority with a wireless terminal at every automatic return thereof from a power save state to transit the wireless terminal to the power save state.

13. The wireless terminal management program according to claim 12, wherein, upon adjusting the start timing of power saving at said step for adjusting a start timing of power saving, the start timing of power saving with regard to each of the wireless terminals operable intermittently is adjusted so that there is an interval longer than at least two beacon periods between mutual generation of each return timing.

14. The wireless terminal management program according to claim 12, wherein, upon adjusting the start timing of power saving on a newly entering wireless terminal operable intermittently at said step for adjusting a start timing of power saving, in a case where there is no beacon frame which does not overlap the other return timings in a predetermined number of continuous beacon frames, the start timing of power saving is adjusted so that a beacon frame with a smallest number of overlapping return timings is set to be the return timing.