Noise margin information for power control and link adaptation in IEEE 802.11h WLAN

Abstract

A method and apparatus for adjusting the transmission power level or transmission data rate between a plurality of stations located within the coverage area of a basic service set (BSS) or in an independent basic service set (IBSS) in a wireless local area network (WLAN). The receiving station extracts a transmission data rate from an incoming signal, determines a signal-to-noise ratio (SNR) for the incoming signal, and then calculates noise margin information based on a difference between the SNR of the incoming signal and a minimum SNR MIN for the extracted data rate. The noise margin is then transmitted back to the original transmitting station and using the noise margin information, the transmit power level and/or the transmission rate of this station may be adjusted accordingly.

What is claimed is: 
     
       1. A method for transmitting data among stations in a wireless local area network (WLAN), comprising:
 determining, at a receiving station, a measure of received signal power of a signal received from a transmitting station; 
 calculating by the receiving station a noise margin based on a difference between the measure of received signal power and a power measure required for reliable communication at a predetermined data rate of the signal; and 
 transmitting the noise margin from the receiving station to the transmitting station. 
 
     
     
       2. The method of  claim 1 , further including:
 receiving the noise margin at the transmitting station, and 
 adjusting at least one of a transmit power level and a transmission rate of the transmitting station based on the noise margin. 
 
     
     
       3. The method of  claim 1 , wherein:
 determining the measure of received signal power includes determining a signal-to-noise ratio (SNR) of the received framesignal; and 
 calculating the noise margin includes determining a difference between the SNR and a minimum acceptable signal-to-noise ratio (SNR MIN ). 
 
     
     
       4. The method of  claim 1 , further comprising storing said noise margin in a memory medium at the receiver. 
     
     
       5. The method of  claim 1 , wherein the transmitting station is located within a basic service set (BSS) or an independent basic service set (IBSS). 
     
     
       6. The method of  claim 1 , wherein the receiving station is a mobile unit located within a basic service set (BSS) or an independent basic service set (IBSS). 
     
     
       7. A method for transmitting data among a plurality of stations located within the coverage area of a basic service set (BSS) in a wireless local area network (WLAN) comprising:
 transmitting a first frame from a transmitting station; 
 receiving the first frame at the receiving station; 
 determining, at the receiving station, a transmission data rate of the first frame; 
 calculating, by the receiving station, a signal-to-noise ratio (SNR) of the first frame; 
 calculating, by the receiving station, a noise margin based on a difference between the SNR and a minimum acceptable signal-to-noise ratio (SNR MIN ) for the data rate; 
 transmitting the noise margin from the receiving station; 
 receiving the noise margin at the transmitting station; 
 calculating, by the transmitting station, at least one of a new transmit power level and new transmission data rate based on the noise margin; and, 
 adjusting, at the transmitting station, at least one of a transmit power level and the transmission data rate to the at least one of a new transmit power level and a new transmission data rate. 
 
     
     
       8. The method of  claim 7 , further comprising:
 transmitting, by the receiving station, a second noise margin to a second station and 
 adjusting at least one of a transmission power level and a transmission rate of the second station based on the second noise margin. 
 
     
     
       9. The method of  claim 7 , wherein the receiving station or the transmitting station are mobile units. 
     
     
       10. An apparatus for determining the transmission power level between a plurality of non access point stations located within the coverage area of a basic service set (BSS) in a wireless local area network (WLAN), comprising:
 means for receiving an incoming signal from a first station; 
 means for demodulating said incoming signal; 
 means for determining a transmission data rate and a measure of received signal power of the incoming signal; 
 means for calculating a noise margin based on a difference between the measure of received signal power and a power measure required for a predetermined threshold of communication for the transmission data rate; 
 means for transmitting said noise margin to the said first station, and, 
 means for storing said noise margin for a subsequent retrieval. 
 
     
     
       11. The apparatus of  claim 10 , further comprising means for adjusting at least one of a transmit power level and a transmission rate of the apparatus, in response to said noise margin. 
     
     
       12. The apparatus of  claim 10 , further comprising means for modulating signals indicative of said noise margin. 
     
     
       13. The apparatus of  claim 10 , wherein the noise margin is stored for a predetermined time period. 
     
     
       14. The apparatus of  claim 10 , wherein said signal is transmitted by a transmitting station located within a basic service set (BSS) or an independent basic service set (IBSS). 
     
     
       15. The method of  claim 1 , wherein the transmitting station is an access point (AP) located with a basic service set (BSS). 
     
     
       16. The method of  claim 1 , wherein the receiving station is an access point (AP) located with a basic service set (BSS). 
     
     
       17. The apparatus of  claim 10 , wherein the first station is an access point (AP) located with a basic service set (BSS). 
     
     
       18. An apparatus comprising:
 a transmitter that is configured to transmit a signal at a transmit power level and a transmit data rate, 
 a receiver that is configured to receive a noise margin corresponding to receipt of the signal at a receiving station, wherein the noise margin is based on a difference between a measure of received signal power and a power measure required for reliable communication at a predetermined data rate of the signal, and 
 a processor that is configured to calculate an adjustment to at least one of the transmit power level and transmit data rate based on the noise margin, and to correspondingly adjust the at least one transmit power level and transmit data rate. 
 
     
     
       19. The apparatus of  claim 18 , wherein the apparatus is a mobile station. 
     
     
       20. The apparatus of  claim 18 , wherein the apparatus is an access point (AP) located with a basic service set (BSS). 
     
     
       21. A method for transmitting data among stations in a wireless local area network (WLAN), the method comprising acts of: determining, at a receiving station, a transmission data rate and a measure of received signal power of a signal received from a transmitting station; calculating by the receiving station a noise margin based on a difference between the measure of received signal power and a power measure required for a predetermined threshold of communication for the transmission data rate; and transmitting the noise margin from the receiving station to the transmitting station. 
     
     
       22. The method of claim 21, further comprising acts of: receiving the noise margin at the transmitting station; and adjusting at least one of a transmit power level and a transmission rate of the transmitting station based on the noise margin. 
     
     
       23. The method of claim 21, wherein determining the measure of received signal power comprises acts of: determining a signal-to-noise ratio (SNR) of the received signal; and calculating the noise margin includes determining a difference between the SNR and a minimum acceptable signal-to-noise ratio. 
     
     
       24. The method of claim 21, further comprising an act of storing the noise margin in a memory at the receiver. 
     
     
       25. The method of claim 21, further comprising an act of storing the measure of received signal power in a memory at the receiver. 
     
     
       26. The method of claim 21, wherein the transmitting station is located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS). 
     
     
       27. The method of claim 21, wherein the receiving station is a mobile unit located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS). 
     
     
       28. A receiver for receiving data transmitted from a transmitting station in a wireless local area network, the receiver comprising: a processor configured to: determine at the receiver, a transmission data rate and a measure of received signal power of a signal received from the transmitting station; calculate by the receiving station a noise margin based on a difference between the measure of received signal power and a power measure required for a predetermined threshold of communication for the transmission data rate; and transmit the noise margin from the receiving station to the transmitting station. 
     
     
       29. The receiver of claim 28, further comprising: a signal to noise measurement circuit configured to determine the measure of received signal power by determining a signal-to-noise ratio (SNR) of the received signal; and the processor is configured to calculate the noise margin by determining a difference between the SNR and a minimum acceptable signal-to-noise ratio. 
     
     
       30. The receiver of claim 28, further comprising a memory and the processor is configured to store the noise margin in the memory. 
     
     
       31. The receiver of claim 28, further comprising a memory and the processor is configured to store the measure of received signal power in the memory. 
     
     
       32. The receiver of claim 28, wherein the receiver is a mobile unit located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS)). 
     
     
       33. An apparatus for determining the transmission power level between a plurality of wireless stations in a wireless local area network (WLAN), the apparatus comprising:
 a receiver configured to receive an incoming signal from a first station; a demodulator configured to demodulate the incoming signal; and a processor configured to determine a transmission data rate and a measure of received signal power of the incoming signal, calculate a noise margin based on a difference between the measure of received signal power and a power measure required for a predetermined threshold of communication for the transmission data rate, and transmit the noise margin to the first station.   
     
     
       34. The apparatus of claim 33, further comprising a memory wherein the processor is configured to store the noise margin in the memory. 
     
     
       35. The apparatus of claim 33, further comprising a memory wherein the processor is configured to store the measure of received signal power in the memory. 
     
     
       36. The apparatus of claim 33, wherein the processor is configured to adjust at least one of a transmit power level and a transmission rate of the apparatus, in response to the noise margin. 
     
     
       37. The apparatus of claim 33, further comprising a modulator configured to modulate signals indicative of the noise margin. 
     
     
       38. The apparatus of claim 33, wherein the noise margin is stored for a predetermined time period. 
     
     
       39. The apparatus of claim 33, wherein the signal is transmitted by a transmitting station located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS). 
     
     
       40. The apparatus of claim 33, wherein the first station is an access point (AP) located with a basic service set (BSS).  
     
     
       41. A method for transmitting data among stations in a wireless local area network (WLAN), the method comprising acts of: determining, at a receiving station, a measure of received signal power of a signal received from a transmitting station; calculating by the receiving station a noise margin based on a difference between the measure of received signal power and a minimum power measure for a transmission data rate; and transmitting the noise margin from the receiving station to the transmitting station. 
     
     
       42. The method of claim 41, further comprising acts of: receiving the noise margin at the transmitting station; and adjusting at least one of a transmit power level and a transmission rate of the transmitting station based on the noise margin. 
     
     
       43. The method of claim 41, wherein determining the measure of received signal power comprises acts of: determining a signal-to-noise ratio (SNR) of the received signal; and calculating the noise margin includes determining a difference between the SNR and a minimum acceptable signal-to-noise ratio. 
     
     
       44. The method of claim 41, further comprising an act of storing the noise margin in a memory at the receiver. 
     
     
       45. The method of claim 41, further comprising an act of storing the measure of received signal power in a memory at the receiver. 
     
     
       46. The method of claim 41, wherein the transmitting and receiving stations are located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS). 
     
     
       47. An apparatus comprising: a transmitter that is configured to transmit a signal at a transmit power level and a transmit data rate to a receiving station; a receiver that is configured to receive a noise margin corresponding to receipt of the signal at the receiving station, wherein the noise margin is based on a difference between a measure of received signal power and a minimum power measure for a transmission data rate; and a processor that is configured to calculate an adjustment to at least one of the transmit power level and transmit data rate based on the noise margin, and to correspondingly adjust the at least one transmit power level and transmit data rate. 
     
     
       48. The apparatus of claim 47, wherein the apparatus is a mobile station. 
     
     
       49. The apparatus of claim 47, wherein the apparatus is an access point (AP) located with a basic service set (BSS). 
     
     
       50. A station in a wireless local area network (WLAN), the station comprising:
 a processor configured to determine a measure of received signal power of a signal received from a transmitting station; calculate a noise margin based on a difference between the measure of received signal power and a minimum power measure for a transmission data rate; and transmit the noise margin to the transmitting station.    
     
     
       51. The station of claim 50, further comprising a receiver configured to receive the noise margin, wherein the processor is configured to adjust at least one of a transmit power level and a transmission rate based on the noise margin. 
     
     
       52. The station of claim 50, comprising a signal-to-noise measurement circuit configured to determine a signal-to-noise ratio (SNR) of the received signal, wherein the processor is configured to determine a difference between the SNR and a minimum acceptable signal-to-noise ratio. 
     
     
       53. The station of claim 50, further comprising a memory, wherein the processor is configured to store the noise margin in the memory. 
     
     
       54. The station of claim 50, further comprising a memory, wherein the processor is configured to store the measure of received signal power in the memory. 
     
     
       55. The station of claim 50, wherein the station is located within a basic service set (BSS) which is one of an infrastructural BSS and an independent basic service set (IBSS).