the power margin is an adjacency parameter, isn’t it ?
in this case you could set :
power margin (railway cell, standard cell) = 12db
power margin (railway cell, railway cell) = 3db
power margin (standard cell, railway cell) = 12db
That will certainly help. You see the idea behind these values ? Maybe you can use other parameters to achieve the same effects, as I’m not sure what are the nokia’s HO ALGORITHMS.
I don’t know the nokia parameters, sorry.