This paper proposes a dynamic spectrum access system for underground wireless communication——a
dynamic spectrum sharing system under interference temperature constrains. It can make the best of spectrum resources
and improve the utilization efficiency. Then, a multi-dimensional Markov chain is used to model the system. On the basis,
the secondary users’ performance under interference temperature constrains is obtained. As two important performance
indexes to measure secondary users’ performance, cognitive users’ interrupting probability and blocking probability are
calculated. Finally, cognitive users’ performance under different users’ access is analyzed, and the performances in
dynamic spectrum access system and overlay access system are compared. Simulation results indicate that the dynamic
spectrum sharing access system under interference temperature constrains is superior to the overlay access system and
helpful to improve the spectrum sharing system in coal mines.