Nonlinear　distortions　generated　by　the　power　amplifier　(PA)　will　affect　the　performance　of　channel　estimation　thus　the　veracity　of　signal　detection　for　ultra-wideband　(UWB)　orthogonal　frequency-division　multiplexing　(OFDM)　systems.　The　existing　nonlinear　cancellation　techniques　for　tackling　this　problem　reduce　the　overhead　of　the　system　due　to　the　large　number　of　pilot　subcarriers　required.　As　the　UWB　channel　can　usually　be　modeled　as　sparse,　an　iterative　method　that　estimates　the　sparse　channel　and　recovers　the　original　signal,　referred　to　as　SCE-DSD,　is　proposed　in　this　letter.　Involving　the　nonlinear　distortion　in　the　measurement　matrix　construction,　SCE-DSD　estimates　the　channel　and　the　original　signal　sequentially.　The　numerical　results　show　that,　compared　to　the　state-of-the-art　method,　the　proposed　method　has　a　better　performance　using　a　smaller　number　of　pilot　subcarriers.　©　2012　IEEE.