The using of mlseeq function

Hi all,

I am transmitting a sequence of N=1000 bits over an ISI channel of length 4, and then I am trying to use maximum likelihood sequence estimator (mlseeq) to estimate the transmitted sequence. I am using BPSK as the modulation scheme. Based on the MATLAB help, I wrote the mlseeq function as:

mlseeq(y,h,[-1;1],16,'rst')

where y is the received sequence, h is the channel coefficients, [-1;1] is the vector of the ideal constellation points.

However, the BER curve I got is not smooth and fluctuating up and down (i.e.: not decaying in general). Is there any thing wrong in the above use of mlseeq?

Thanks in advance