where P n ∗ = max { ( 1 λ − N 0 | h ¯ n | 2 ) , 0 } {\displaystyle P_{n}^{*}=\max \left\{\left({\frac {1}{\lambda }}-{\frac {N_{0}}{|{\bar {h}}_{n}|^{2}}}\right),0\right\}} and | h ¯ n | 2 {\displaystyle |{\bar {h}}_{n}|^{2}} is the gain of subchannel n {\displaystyle n} , with λ {\displaystyle \lambda } chosen to meet the power constraint.