This paper proposes efficient schemes for wireless cellular base stations to utilize TV white spectrum (such base stations referred to as white base stations - WBS), so that WBSes can provide good services to their end terminals without violating the incumbent TV services. In particular, we consider two complementary problems. On the one hand, given a set of TV stations and white base stations, maximum permitted transmit power levels on all channels for each base stations needs to be determined. By use of convex programming, we propose here an improved, centralized mechanism. On the other hand, once the maximum transmit powers are determined, each white base station needs to choose a channel with the maximal permitted power on that channel such that the resulting cell performance is improved. Allocating channels with nonidentical transmission power and asymmetric interference is formulated into congestion game for the first time, and an algorithm is derived thereafter which converges after a small number of iterations in simulation. However, the scheme requires geo information coupled with a radio map to decide at each WBS in a decentralized manner about the channel usage. We find that in comparison to several other decentralized schemes, our proposed approach first of all converges after a small number of iterations while on the other hand it is able to achieve the same network performance spending significantly lower transmit power. ; QC 20131213