Currently I am trying to design an equalizer based on variable step size (VSS) NLMS algorithm. The adaptation of the step size is based on the instataneous squared error. The number of taps is 55. My initial step size (which is also equivalent to max. step size allowable) is 0.6 and the minimum step size allowable is 0.35, with the "Alpha" = 0.97, "Gamma" = 0.0005. I compare it to the conventional NLMS algorithm with the same tap length and step size of 0.4 It is found that both algorithms achieve similar steady state error but the conventional NLMS algorithm still can achieve faster speed as compared to the VSS NLMS. What is the problem actually? Anything wrong with the setting of maximum step size, Alpha and Gamma? Can anyone please help? Many thanks.

# Variable step size LMS

Started by ●November 15, 2006

Reply by ●November 16, 20062006-11-16

Richard_K wrote:> Currently I am trying to design an equalizer based on variable step size > (VSS) NLMS algorithm. The adaptation of the step size is based on the > instataneous squared error. The number of taps is 55. My initial step size > (which is also equivalent to max. step size allowable) is 0.6 and the > minimum step size allowable is 0.35, with the "Alpha" = 0.97, "Gamma" = > 0.0005. I compare it to the conventional NLMS algorithm with the same tap > length and step size of 0.4 It is found that both algorithms achieve > similar steady state error but the conventional NLMS algorithm still can > achieve faster speed as compared to the VSS NLMS. What is the problem > actually? Anything wrong with the setting of maximum step size, Alpha and > Gamma?Those are the wrong questions. The right questions are what has to be accomplished as the result and if and why VSS can help it. Can anyone please help? Many thanks. I was always wondering why peolpe are jerking Matlab instead of reading books. VLV

Reply by ●November 16, 20062006-11-16

I found out that my step size keep varying around the initial step size that I set. Can I anyone please help?>Currently I am trying to design an equalizer based on variable step size >(VSS) NLMS algorithm. The adaptation of the step size is based on the >instataneous squared error. The number of taps is 55. My initial stepsize>(which is also equivalent to max. step size allowable) is 0.6 and the >minimum step size allowable is 0.35, with the "Alpha" = 0.97, "Gamma" = >0.0005. I compare it to the conventional NLMS algorithm with the sametap>length and step size of 0.4 It is found that both algorithms achieve >similar steady state error but the conventional NLMS algorithm still can >achieve faster speed as compared to the VSS NLMS. What is the problem >actually? Anything wrong with the setting of maximum step size, Alphaand>Gamma? Can anyone please help? Many thanks. >