Power control in a communication network and method

• US 7,835,384 B2
• Filed: 07/01/2004
• Issued: 11/16/2010
• Est. Priority Date: 07/01/2004
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Rommer, Stefan, Pettersson, Jonas, Furuskär, Anders, Simonsson, Arne
• Primary Examiner(s): West; Lewis G
• Assistant Examiner(s): Shen; Qun
• Application Number:
  US11/571,561
• Publication Number:
  US 20070223403A1
• Time in Patent Office: 2,329 Days
• Field of Search: 370/332, 370/315, 370/338, 370/330, 370/337, 370/445, 455/423, 455/426.1, 455/522, 455/448
• US Class Current: 370/445
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

In a wireless network using a carrier sense multiple access (CSMA) scheme is provided a method, system, devices and instruction sets for detecting transmission levels and adjusting the transmission levels for both a connection point and mobile stations within the network in order to reduce power consumption in network devices and minimize interference problems while keeping hidden node problems on a controlled level.

Claims

1. A method for controlling wireless coverage in a wireless network with a carrier sense multiple access (CSMA) scheme, comprising the steps of:

detecting transmissions with respect to a predetermined quality level;

adjusting a transmission power level in a connection point to a minimum transmit power Pminap by determining a carrier sensing distance from the connection point using an estimation of a distance to a remotest mobile station associated with the connection point to enable essentially all mobile station or stations within a cell to detect transmissions from said connection point;

adjusting a transmission power level of each mobile station to a minimum transmit power Pminms where the Pminms is set to the minimum transmit power Pminap plus a margin M where the margin M is set only large enough to enable said mobile station or stations to detect transmissions from the other mobile stations within the cell.

2. The method according to claim 1, wherein said transmission quality level is determined on a continuous or regular basis.

3. The method according to claim 1, wherein the

step of detecting transmission quality level further comprises the steps of:

detecting said transmission quality level in mobile stations; and

sending a message to said connection point with information about said detection.

4. The method according to claim 3, wherein said message is sent using a Beacon report message available in the IEEE 802.11k protocol.

5. The method according to claim 1, wherein said step of detecting said transmission quality comprises detecting in a first mobile station a partial message exchange between nodes belonging to the same cell as said first mobile station.

6. The method according to claim 5, further comprising the step of using a hidden node report available in a wireless communication protocol for distributing information about said detection of partial message exchanges.

7. The method according to claim 1, wherein said detection of transmission quality includes the step of measuring transmission signal strength.

8. The method according to claim 7, further comprising the step of:

enabling one or several mobile stations outside an adjusted coverage area determined by said transmission signal strength to associate with said connection point using an alternating transmission power level of said connection point between an adjusted power level and a higher power level.

9. The method according to claim 7, further comprising the step of:

enabling one or several mobile stations outside an adjusted coverage area determined by said transmission signal strength to associate with said connection point by responding to active scanning with higher power than the adjusted power level.

10. The method according to claim 7, wherein the step of detecting transmissions with signal strengths with respect to a predetermined threshold further comprises the steps of:

measuring transmission quality levels from said mobile stations in said connection point; and

estimating a coverage area using said measured transmission quality levels and knowing output transmission power levels of said mobile stations.

11. The method according to claim 3, further comprising the step of:

using a jump procedure for adjusting transmission power levels, said jump procedure comprising the steps of;

gradually changing said transmission levels;

detecting incorrect transmission levels; and

changing, in opposite direction as compared to said gradual change, said transmission levels in response to said message detection.

12. A wireless network with a carrier sense•

multiple access (CSMA) scheme, said network comprising;

a connection point in connection with a packet based network;

at least one mobile station associated with said connection point;

wherein said connection point and said at least one mobile station comprise detection means arranged to detect transmissions with respect to a predetermined quality level, said connection point is arranged with power level adjustment means to adjust a transmission power level to a minimum transmit power Pminap by determining a carrier sensing distance from the connection point using an estimation of a distance to a remotest mobile station associated with the connection point to enable essentially all mobile stations within a cell to detect transmissions from said connection point, and each mobile station is arranged to adjust a transmission power level to a minimum transmit power Pminms where the Pminms is set to the minimum transmit power Pminap plus a margin M where the margin M is set only large enough to enable one or several mobile stations to detect transmissions from the other mobile stations within the cell.

13. The network according to claim 12, wherein said transmission quality level is determined on a continuous or regular basis.

14. The network according to claim 12, further comprising:

means for detection of said transmission quality level in mobile stations; and

means for transmission of a message to said connection point with information about said detection.

15. The network according to claim 14, wherein said message is sent using a Beacon report message available in the IEEE 802.11k protocol.

16. The network according to claim 12, wherein said detection of said transmission quality comprise detecting in a first mobile station a partial message exchange between nodes belonging to the same cell as said first mobile station.

17. The network according to claim 16, further comprising an arrangement for using a hidden node report available in a wireless communication protocol for distributing information about said detection of partial transmission exchange.

18. The network according to claim 14, wherein said detection of transmission quality includes a measurement of transmission signal strength.

19. The network according to claim 14, further comprising an arrangement for using a jump algorithm for adjusting transmission power

levels, said jump algorithm comprising the steps of:

gradually changing said transmission levels;

detecting incorrect transmission levels; and

changing, in opposite direction as compared to said gradual change, said transmission levels in response to said message detection.

20. The network according to claim 18, further comprising an arrangement for allowing at least one mobile station outside a coverage area determined by said transmission signal strength to associate with said connection point.

21. The network according to claim 20, further comPrising means for extending said coverage area if a mobile station outside said coverage area has associated with said connection point.

22. The network according to claim 18, further comprising an arrangement for enabling mobile stations outside an adjusted coverage area determined by said transmission signal strength to associate with said connection point using an alternating transmission power level of said connection point between said adjusted power level and a higher power level.

23. The network according to claim 18, further comprising an arrangement for enabling mobile stations outside an adjusted coverage area determined by said transmission signal strength to associate with said connection point using an active or passing scanning method.

24. The network according to claim 12, wherein the detection means arranged to detect transmissions with respect to a predetermined quality level further comprises an arrangement for:

measuring transmission levels by said mobile stations at said connection point; and

estimating a coverage model using said measured transmission levels and knowing output transmission power levels of said mobile stations.

25. A connection point device usable in a network according to claim 12, wherein said connection point being arranged to detect transmissions with respect to a predetermined quality level, and being arranged to adjust a transmission power level to enable essentially all mobile stations within a cell to detect transmissions from said connection point.

26. A mobile station device usable in a network according to claim 12, wherein said mobile stations being arranged to adjust transmission power levels to enable mobile stations to detect transmissions from other mobile stations within a coverage cell.

27. A wireless network system with a carrier sense multiple access (CSMA) scheme, said network comprising:

a connection point in connection with a packet based network;

at least one mobile station associated with said access point; and

wherein said connection point and said at least one mobile station are arranged to detect transmissions with respect to a predetermined quality level, said connection point being arranged to adjust a transmission power level to a minimum transmit power Pminap by determining a carrier sensing distance from the connection point using an estimation of a distance to a remotest mobile station associated with the connection point in response to said detection of transmission with respect to said predetermined quality level to enable essentially all mobile stations within a cell to detect transmissions from said connection point, and each mobile station being arranged to adjust a transmission power level to a minimum transmit power Pminms in response to said detection with respect to said predetermined quality level where the Pminms is set to the minimum transmit power Pminap plus a margin M where the margin M is set only large enough to enable mobile stations to detect transmissions from the other mobile stations within the cell.

28. The system according to claim 27, wherein said transmission quality level is determined on a continuous or regular basis.

29. The system according to claim 27, wherein the detection of transmissions with respect to a predetermined quality level is further arranged for:

detection of said transmission quality level in mobile stations; and

transmission of a message to said connection point with information about said detection.

30. The system according to claim 29, wherein said message is sent using a Beacon report message available in the IEEE 802.11k protocol.

31. The system according to claim 27, wherein

said detection of said transmission quality comprise detecting in a first mobile station a partial message exchange between nodes belonging to the same cell as said first mobile station.

32. The system according to claim 31, further

comprising an arrangement for using a hidden node report available in a wireless communication protocol for distributing information about said detection of partial transmission exchange.

33. The system according to claim 29, wherein said detection of transmission quality includes a measurement of transmission signal strength.