A study on the turbo interleaver of WCDMA and CDMA2000

Abstract

The specification groups of IMT2000 accepted the turbo code for one of the channel coding scheme because of its good performance. For the constituent encoder of turbo code, 3GPP and 3GPP2 propose the RSC which has the same structure. But the structures of turbo interleaver are different between WCDMA and cdma2000. So the difference of BER performance is the result of the difference of turbo interleaver. In this thesis, in order to compare the turbo interleaver which is recommended by WCDMA and cdma2000, HW is implemented according to the specification. After the VHDL coding, the design of the WCDMA turbo interleaver was synthesized targeting the Vertex1000 and the design of the cdma2000 turbo interleaver was synthesized targeting the Spartan40. The performance of turbo code is divided into the ``waterfall region`` and ``error floor region``. The ``error floor region`` of the performance are analyzed by the difference of the free distance. For the comparison of WCDMA and cdma2000, both cases use 378 block size. In order to confirm that the free distance term in the union bound on the BER performance dominates the bound for the error floor region, some distance spectrum informations are used.