  The challenge of self-optimization for orthogonal frequency-division
multiple-access (OFDMA) interference channels is that users inherently compete
harmfully and simultaneous water-filling (WF) would lead to a
Pareto-inefficient equilibrium. To overcome this, we first introduce the role
of environmental interference derivative in the WF optimization of the
interactive OFDMA game and then study the environmental interference derivative
properties of Stackelberg equilibrium (SE). Such properties provide important
insights to devise free OFDMA games for achieving various SEs, realizable by
simultaneous WF regulated by specifically chosen operational interference
derivatives. We also present a definition of all-Stackelberg-leader equilibrium
(ASE) where users are all foresighted to each other, albeit each with only
local channel state information (CSI), and can thus most effectively reconcile
their competition to maximize the user rates. We show that under certain
environmental conditions, the free games are both unique and optimal.
Simulation results reveal that our distributed ASE game achieves the
performance very close to the near-optimal centralized iterative spectrum
balancing (ISB) method in [5].
