Interference reduction efficiency of a turbo coded CDMA multilayer system equipped with a pilot canceler

We considered a turbo coded DS-CDMA multilayer system equipped with a pilot canceler in a mobile communications environment. The proposed system multiplexes data at different speeds using orthogonal codes. Besides, assigning 30% of the total transmission power to a pilot channel, stable synchronization and coherent demodulation can be performed under a low Eb/No. However, asynchronous transmission assigning too much power to the pilot channel causes an increase of interference for the other code channels. We estimate the interference reduction efficiency of the proposed system using computer simulation for two kinds of power allocation and two kinds of interleave size. The result indicates that if the data channel power is assigned 2.5% or 5% of the total transmission power and the number of interleave size is 6000, the proposed system is improved more than 4.5 dB larger than the coding gain at a BER=10^-4 than a DS-CDMA multilayer system with ordinary Viterbi (1995) decoder in a fading environment