Power control in wireless communications based on estimations of packet error rate

Abstract

Power is controlled by increasing the power level of a wireless transmission if a number of packet errors in a short observation window exceeds a first threshold. Power is controlled by decreasing the power level of the wireless transmission if a number of packet errors in a long observation window falls below a second threshold. In various embodiments, power is controlled based on packet error rate using both open and closed loop feedback to manage power at an increased level of granularity.

1 . A method comprising: 
 increasing the power level of a wireless transmission by using power control that is capable of being open loop or capable of being closed loop, wherein said open loop power control enables a transmitter to unilaterally modify the power based on packet errors if a number of packet errors in a short observation window exceeds a first threshold; and    decreasing, by using power control that is capable of being open loop or capable of being closed loop, the power level of the wireless transmission if a number of packet errors in a long observation window falls below a second threshold.    
   
   
       2 . The method of  claim 1  further comprising: 
 increasing the power level of the wireless transmission if the number of packet errors in the long observation window exceeds a third threshold.    
   
   
       3 . The method of  claim 1  wherein increasing the power level comprises: 
 counting the number of packet errors during the short observation window; and comparing the number of packet errors during the short observation window to the first threshold.    
   
   
       4 . The method of  claim 1  wherein decreasing the power level comprises: 
 counting the number of packet errors during the long observation window; and comparing the number of packet errors during the long observation window to the second threshold.    
   
   
       5 . The method of  claim 1  wherein said open loop power control used to increase and/or decrease the power level comprises: 
 receiving a plurality of data packets comprising the wireless transmission from a remote source;    performing a cyclic redundancy check (CRC) on each of the plurality of packets, wherein a CRC failure indicates a packet error; and    sending a negative acknowledgement (NACK) message to the remote source for each CRC failure, said remote source to count a number of NACK messages corresponding to the number of packet errors in the short observation window and a number of NACK messages corresponding to the number of packet errors in the long observation window, and said remote source to increase and/or decrease the power level accordingly.    
   
   
       6 . The method of  claim 1 , wherein said open loop power control used to increase and/or decrease the power level comprises: 
 sending a plurality of packets of data comprising the wireless transmission to a remote destination, said remote destination to perform a cyclic redundancy check (CRC) on each of the plurality of packets, wherein a CRC failure indicates a packet error;    receiving a negative acknowledgement (NACK) message from the remote destination for each CRC failure;    counting a number of NACK messages corresponding to the number of packet errors in the short observation window and increasing the power level accordingly; and counting a number of NACK messages corresponding to the number of packet errors in the long observation window and decreasing the power level accordingly.    
   
   
       7 . The method of  claim 1 , wherein said closed loop power control used to increase and/or decrease the power level comprises: 
 receiving a plurality of packets of data comprising the wireless transmission from a remote source;    performing a cyclic redundancy check (CRC) on each of the plurality of packets, wherein a CRC failure indicates a packet error;    counting a number of CRC failures in the short observation window;    sending an instruction to the remote source to increase the power level if the number of CRC failures in the short observation window exceeds the first threshold;    counting a number of CRC failures in the long observation window; and    sending an instruction to the remote source to decrease the power level if the number of CRC failures in the long observation window is below the second threshold.    
   
   
       8 . The method of  claim 7 , wherein the closed loop power control further comprises: 
 sending the instruction to the remote source to increase the power level if the number of CRC failures in the long observation window exceeds a third threshold.    
   
   
       9 . The method of  claim 7  wherein the instruction to increase the power level and the instruction to decrease the power level comprise Link Manager Protocol (LMP) instructions.  
   
   
       10 . The method of  claim 1  wherein the wireless transmission comprises a first wireless transmission generated by a transmitter located in close proximity to a receiver, said receiver to simultaneously receive a second wireless transmission, said first wireless transmission to create an interference signal in the second wireless transmission in proportion to the power level of the first wireless transmission, and wherein increasing and/or decreasing the power level comprise: 
 maintaining a target average packet error rate using a lowest average power level of the first wireless transmission.    
   
   
       11 . The method of  claim 1  wherein the target average packet error rate is 0.01.  
   
   
       12 . The method of  claim 1  wherein the power level of the wireless transmission has a 30 dB range and the power level is adjustable in 2 dB steps.  
   
   
       13 . The method of  claim 1 , wherein the short observation window is 35 contiguous packets, the long observation window is 135 contiguous packets, the first threshold is one packet error, and the second threshold is one packet error.  
   
   
       14 . The method of  claim 2 , wherein the third threshold is three packet errors.  
   
   
       15 . The method of  claim 1  wherein the wireless transmission comprises a Bluetooth data link.  
   
   
       16 . A machine readable medium having stored thereon machine readable instructions to implement a method comprising: 
 increasing, by using power control that is capable of being open loop or capable of being closed loop, wherein said open loop power control enables a transmitter to unilaterally modify the power based on packet errors, a power level of a wireless transmission if a number of packet errors in a short observation window exceeds a first threshold; and    decreasing the power level of the wireless transmission if a number of packet errors in a long observation window falls below a second threshold.