Transmit power management in shared-communications channel networks

• US 7,742,443 B2
• Filed: 02/28/2003
• Issued: 06/22/2010
• Est. Priority Date: 05/28/2002
• Status: Expired due to Fees

• Current Assignee: Intellectual Ventures I LLC (Intellectual Ventures LLC)
• Original Assignee: Xocyst Transfer AG LLC (Intellectual Ventures LLC)
• Inventors: Wentink, Maarten Menzo
• Primary Examiner(s): Duong; Frank
• Assistant Examiner(s): Mered; Habte
• Application Number:
  US10/377,324
• Publication Number:
  US 20040029590A1
• Time in Patent Office: 2,671 Days
• Field of Search: 370/338, 370/332, 370/349, 370/394, 370/401, 370/252, 370/327, 370/310, 370/315, 370/329, 370/330, 370/331, 370/333, 370/334, 370/341, 370/342, 370345-350, 370445-447, 455/450, 455/500, 455/67.13, 455/69, 455/522, 714/18, 714/749, 375/224, 375/227, 375/316, 375/324, 375/329
• US Class Current: 370/318
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A method of ameliorating the hidden node problem in wireless local area networks employing power control is disclosed. The illustrative embodiments function in a variety of ways that have a common theme: while the Data Frames are transmitted at lesser potency, at least one of the control frames—Request-to-Send, Clear-to-Send, and Acknowledgement—associated with the Data Frame are sent at a greater potency. This causes at least one of the “loud” control frames to be heard and decoded by all of the potentially contending stations. And because the control frames carry duration information for the virtual carrier sense mechanism, their reception suppresses transmissions by potentially-contending stations that cannot sense the “quiet” Data Frames.

Claims

1. A method for transmitting data in a wireless network comprising:

transmitting from a station a request-to-send (RTS) frame at a first potency, wherein the first potency is determinable, based at least in part on, a first bit rate and a first radiated power level;

receiving at the station a clear-to-send (CTS) frame in response to the RTS frame, wherein the CTS frame has a second potency determinable, based at least in part on, a second bit rate and a second radiated power level;

transmitting from the station a data frame in response to the CTS frame, wherein the data frame is transmitted at a third potency determinable, based at least in part on, a third bit rate and a third radiated power level; and

receiving at the station an acknowledgment frame as a response to the data frame, wherein the acknowledgment frame has a fourth potency determinable, based at least in part on, a fourth bit rate, a fourth radiated power level, and a frame size of the acknowledgement frame,

wherein at least one of the first potency, the second potency, and the fourth potency is greater than the third potency, and

wherein the third bit rate is greater than at least one of the first bit rate and the second bit rate.

2. The method of claim 1, wherein only the first potency is greater than the third potency and the RTS frame is transmitted to every network station.

3. The method of claim 1, wherein only the second potency is greater than the third potency and the CTS frame is transmitted to every network station.

4. The method of claim 1, wherein only the fourth potency is greater than the third potency and the acknowledgment frame is transmitted to every network station.

5. The method of claim 1, further comprising:

transmitting one or more additional data frames at the third potency; and

receiving one or more additional acknowledgment frames at the fourth potency, wherein each of the one or more additional acknowledgment frames is a response to each of the one or more additional data frames.

6. The method of claim 1, wherein each of the RTS frame, the CTS frame, the data frame, and the acknowledgment frame includes a duration field having a time value that is used to set a Network Allocation Vector at a network station and causing the network station to refrain from transmitting data for a time duration equal to the time value.

7. The method of claim 6, wherein the time value extends through the end of the acknowledgment frame.

8. A method of receiving data frames transmitted in the wireless network comprising:

receiving at a first station a request-to-send (RTS) frame from a transmitting station, wherein the RTS frame has a first potency and wherein the first potency is determinable, based at least in part on, a first bit rate and a first radiated power level

transmitting from the first station a clear-to-send (CTS) frame in response to the RTS frame and the availability of the media channel, wherein the CTS frame is transmitted at a second potency determinable, based at least in part on, a second bit rate and a second radiated power level;

receiving at the first station a data frame as a response to the CTS frame, wherein the data frame has a third potency determinable, based at least in part on, a third bit rate and a third radiated power level; and

transmitting from the first station an acknowledgment frame in response to the data frame, wherein the acknowledge frame has a fourth potency determinable, based at least in art on, a fourth bit rate and a fourth radiated power level,

wherein at least one of the first potency, the second potency, and the fourth potency is greater than the third potency, and

wherein the third bit rate is greater than at least one of the first bit rate and the second bit rate.

9. The method of claim 8, wherein each of the RTS frame, the CTS frame, the data frame, and the acknowledgment frame includes a duration field having a time value that extends through the end of the acknowledgment frame.

10. The method of claim 9, further comprising;

using the time value to set a Network Allocation Vector; and

refraining from transmitting data for at least a time period equal to the time value.

11. The method of claim 9, further comprising:

determining a network station is not a destination of the data frame; and

causing the network station to refrain from transmitting data for at least a time period equal to the time value.

12. The method of claim 8, wherein only the first potency is greater than the third potency and wherein the RTS frame is transmitted to every network station.

13. The method of claim 8, wherein only the second potency is greater than the third potency and wherein the CTS frame is transmitted to every network station.

14. The method of claim 8, wherein only the fourth potency is greater than the third potency and wherein the acknowledgment frame is transmitted to every network station.

15. A system for transmitting data frames in a wireless network comprising:

a transmitter configured to determine a first potency, based at least in part on, at least a first bit rate and a first radiated power level and to transmit a request-to-send (RTS) frame at the first potency; and

a receiver configured to receive a clear-to-send (CTS) frame at a second potency, wherein the CTS frame is a response to the RTS frame and wherein the second potency is determinable, based at least in part on, a second bit rate and a second radiated power level,

wherein the transmitter is further configured to determine a third potency, based at least in part on, a third bit rate and a third radiated power level and to transmit in response to the CTS frame at least one data frame at the third potency,

wherein the third potency is less than at least one of the first potency and the second potency, and

wherein the third bit rate is greater than at least one of the first bit rate and the second bit rate.

16. The system of claim 15, wherein the receiver is configured to receive at least one acknowledgment frame at a fourth potency determinable, based at least in part on, a fourth bit rate and a fourth radiated power level, and wherein each of the at least one acknowledgment frame is a response to each of the at least one data frame.

17. The system of claim 15, further comprising a host interface for receiving data and instructions from a host computer.

18. The system of claim 15, further comprising a processor for converting data received from a host computer into one or more data frames for transmitting onto a shared-communications channel.

19. The system of claim 15, further comprising a memory for storing data and instructions received from a host computer.

20. A system for receiving data frames in a wireless network comprising:

a receiver for receiving a request-to-send (RTS) frame at a first potency, wherein the first potency is determinable, based at least in part on, a first bit rate and a first radiated power level; and

a transmitter for determining a second potency, based at least in part on, a second bit rate and a second radiated power level and for transmitting in response to the RTS frame a clear-to-send (CTS) frame at the second potency,

wherein the receiver is further configured to receive at least one data frame at a third potency, wherein the third potency is determinable, based at least in part on, a third bit rate and a third radiated power level,

wherein the third potency is less than at least one of the first potency and the second potency, and

wherein the third bit rate is greater than at least one of the first bit rate and the second bit rate.

21. The system of claim 20, wherein the transmitter is configured to determine a fourth potency, based at least in part on, one of a fourth bit rate and a fourth coding rate and to transmit in response to the one or more data frame at least one acknowledgment frame at the fourth potency.

22. The system of claim 21, wherein at least one of the first potency, the second potency, and the fourth potency is greater than the third potency.

23. The system of claim 20, further comprising a host interface for receiving instructions from a host computer and for transmitting data to the host computer.

24. The system of claim 20, further comprising a processor for converting one or more data frames to data, wherein the one or more data frames are received via a shared-communications channel.

25. The system of claim 20, further comprising a memory for storing data and instructions.