Rate adapt algorithm for a wireless connection

Abstract

In a radio device, an automatic repeat request circuit communicates data messages to remote radio devices at selected data rates. Responses to the data messages are collected and statistics developed about success rates of the data messages at the selected data rates. A current data rate is selected based on the statistics and a packet is transmitted. The data rate can be adapted using the statistics about success rates of the data messages.

1 . A method comprising:
 at a radio device,
 probing different respective data rates for radio communication on a link between the radio device and a remote radio device; 
 determining success percentages for each respective data rate based on a response to the probing; 
 estimating a throughput for the link for each respective data rate; and 
 selecting the respective data rate that gives maximum throughput for the link. 
   
     
     
         2 . The method of  claim 1  wherein probing comprises:
 selecting a data rate; 
 communicating data from the radio device to the remote radio device; 
 detecting an acknowledgement of the communicated data from the remote radio device; and 
 storing first data indicative of the detected acknowledgement for the selected data rate; 
 or 
 detecting lack of an acknowledgement of the communicated data from the remote radio device; and 
 storing second data indicative of the detected lack of an acknowledgement for the selected data rate. 
 
     
     
         3 . The method of  claim 2  wherein selecting a data rate comprises selecting a Modulation and Coding Scheme (MCS) index. 
     
     
         4 . The method of  claim 2  further comprising:
 estimating minimum possible packet error rate (PER) on higher data rates, based on available information about PER on lower data rates. 
 
     
     
         5 . The method of  claim 2  further comprising:
 determining duration of a change in packet error rate; 
 if the determined duration is longer than a predetermined threshold, possibly changing the selected data rate to a more optimal data rate; and 
 if the determined duration is shorter than the predetermined threshold, maintaining the selected respective data rate without a change.