MATLAB: Issue with passing data through AWGN Channel
UPDATE: Scaling was not adjust for upsample/downsample.   

data = randi([0 3], 1, 2^12); % Generate data
dataMod = qammod(data, 4);  % Modulate data
dataMod_u = 16*upsample(dataMod,256); % Upsample
b = rcosdesign(0.25,8,256,'sqrt');
dataMod_f = filter(b, 1, dataMod_u); % Tx Filter 

channel2 = comm.AWGNChannel('EbNo',15,'BitsPerSymbol',2,'SamplesPerSymbol',256);
ch_out2 = step(channel2, dataMod_f); % Pass through channel
ch_out_f2 = filter(b,1,ch_out2);    % RX Filter
ch_out_f2 = (1/16)*downsample(ch_out_f2,256); % Downsample
scatterplot(ch_out_f2)