In this paper, we present a centralized quasi-static channel assignment for multi-radio WMNs (wireless mesh networks) to provide high-throughput paths. We probe data packets at each wireless access point and estimate the traffic load for each network link using a new load estimation algorithm. So the channel assignment can intelligently assigns channels with the objective of maximizing the aggregate estimated load, which as a result improves the network throughput. Besides, the channel assignment scheme can efficiently utilize multiple channels with only 2 radios for each mesh router. The performance evaluation shows that by using the proposed channel assignment, the network performance can significantly outperform the single-radio IEEE 802.11 network as well as the 2-radio WMN with static 2 channels.