This paper presents the single-carrier block transmission interleaver-division multiple-access（SCBT-IDMA） systems

combining with the advantages of IDMA and SCBT systems

can effectively overcome the influence caused by inter-symbol interference（ISI） and inter-code interference（ICI）.Each user’s data symbol sequence is serial-to-parallel converted

then spread

interleaved and transmitted over frequency-selective fading channels.The receiver estimates and equalizes channels in single-carrier frequency domain based on zero-padding technology in SCBT system

and subsequently combines the turbo iterative detection to effectively detect data symbol sequence.Simulation results show that the capacity of SCBT-IDMA is higher than that of the conventional direct-sequence code division multiple access（DS-CDMA）

IDMA and SCBT DS-CDMA over multi-path channels.