System and method for measuring signal to noise values in an adaptive wireless communication system

A method for determining a signal to noise ratio (“SNR”) for a multi-modulation burst modem which uses multiple modulation techniques for transmitting downlinks from a base station to a node, the node having a preferred modulation technique, the method comprising:

• determining an adaptation factor for each modulation technique;
• selecting a first preferred adaptation factor for use by a node, the first preferred adaptation factor being optimized for a first preferred modulation technique of the node;
• receiving a first portion of a first downlink burst, the first portion being modulated using a first modulation technique;
• determining a first SNR for the first portion using the first preferred adaptation factor;
• if the node receives its preferred modulation technique in a second portion of the first downlink burst,
• then determining a second SNR for the second portion using the first preferred adaptation factor,
• comparing the first and the second SNRs to one or more threshold values,
• selecting a second preferred modulation technique based on the comparison,
• selecting a second preferred adaptation factor that is associated with the second preferred modulation technique;
• and
• if the node does not receive its preferred modulation technique in the second portion of the first downlink burst,
• then comparing the first SNR to the one or more threshold values,
• selecting the second preferred modulation technique based on the comparison,
• selecting the second preferred adaptation factor that is associated with the second preferred modulation technique.

A method for changing a node's preferred modulation technique, the preferred modulation technique having an optimized preferred adaptation factor, the node being configured to receive data from a base station that uses a multi-modulation burst modem to transmit a downlink burst, the method comprising:

• receiving a first portion of a downlink burst, the first portion being modulated using a modulation technique that is more robust than a preferred modulation technique;
• determining a first SNR for the first portion using a preferred adaptation factor that is optimized for the preferred modulation technique;
• receiving a second portion of the downlink burst, the second portion being modulated using the preferred modulation technique;
• determining a second SNR for the second portion using the preferred adaptation factor;
• comparing the first and the second SNRs to one or more threshold values;
• and
• selecting a new preferred modulation technique based on the comparison.