In　this　paper,　we　take　both　the　centralized　and　distributed　architectures　into　account　in　heterogenous　cognitive　radio　networks,　and　study　the　problem　of　the　joint　transmission　time　and　power　allocation.　The　problem　is　formulated　as　a　dual　optimization　problem　with　the　optimization　objective　to　maximize　the　total　capacity　of　the　secondary　users　(SUs)　with　the　constraint　of　fairness.　We　first　optimize　the　joint　transmission　time　and　power　allocation　for　centralized　SUs　and　propose　a　corresponding　resource　allocation　scheme　in　the　time-frequency　domain.　Then　for　the　heterogeneous　case　with　both　the　centralized　and　distributed　network　architecture　considered,　we　formulate　the　resource　allocation　problem　as　a　cooperative　game　and　propose　an　iterative　power　water-filling　scheme　to　get　to　the　Nash　Equilibrium　(NE).　Based　on　the　dual　optimization,　a　dynamic　optimal　joint　transmission　time　and　power　allocation　scheme　for　heterogenous　cognitive　radio　networks　is　proposed.　Extensive　simulation　results　are　presented　to　illustrate　the　performance　of　the　proposed　scheme.　©　2011　IEEE.