Equalizer performance enhancements for broadband wireless applications

A method of compensating for gain droop in a modem which stores equalizer coefficients across data bursts between a remote site and a home base, the method comprising:

• receiving channel data values from an equalizer;
• calculating the gain for the equalizer based on the received channel data values;
• and
• scaling the input to the equalizer to achieve a value of 1 based on the calculated gain.

A method of minimizing errors caused by adapting equalizer coefficients for each data burst from a remote site to a home base, the method comprising:

• retrieving a first equalizer coefficient for a current remote site;
• demodulating a data burst from the current remote site;
• determining the S/N ratio for the received burst;
• determining the error rate from the demodulated burst;
• comparing the determined S/N ratio and error rate to defined thresholds;
• and
• updating the first equalizer coefficient based on the comparisons.

A method of improving the convergence of an equalizer in a multi-modulation modem using a two part preamble, the method comprising:

• defining a first part of a preamble with a lower order section, wherein the lower order section is transmitted using QPSK modulation;
• defining a second part of the preamble with a higher order section, wherein the higher order section is transmitted using QAM 64 modulation;
• transmitting both the first and second parts of the preamble;
• receiving the transmitted preamble;
• and
• converging the equalizer based on the received preamble.

A method of providing a soft reset to a modem, the method comprising:

• generating an interrupt to the modem;
• halting a modem interface;
• setting a reset bit;
• flushing a buffer;
• realigning the buffer;
• reprogramming the buffer;
• and
• restarting the modem interface.

A method of determining an adaptation factor for an equalizer based on the expected modulation type of an incoming burst transmission, the method comprising:

• calculating channel characteristics and metrics for a first burst transmission from a remote site;
• comparing the channel characteristics and metrics;
• determining an expected modulation type for a second burst transmission from the remote site based on the comparison;
• selecting an adaptation factor based on the expected modulation type;
• and
• applying the selected adaptation factor to the second burst transmission.