We propose a dynamic scheduler for multichannel 802.15.3 WPANs which exploits both channel reuse and interference control. A maximal-weighted-matching based scheduling scheme is designed to arrange simultaneous transmissions in each single channel and a multichannel assignment scheme is proposed to obtain the ultimate schedule in each superframe. For successful signal decoding, accumulated interference among simultaneous transmissions is taken into account to ensure that signal reception occurs with sufficient SINR. To improve the efficiency of channel reuse, the scheduler fragments each transmission request to multiple requests with the equal duration. An analysis is given of the optimal way to implement such process according to online traffic load and overhead. Simulations are used to evaluate the performance and to compare against existing schemes.