In this paper, we consider the subchannel detection problem in forward link
s for the multicarrier DS-CDMA system when some different subchannel alloca
tion policies are used. An optimal subchannel decision algorithm is propose
d based on the maximum-likelihood (ML) criterion. Theoretical analysis and
simulation results are presented. Furthermore, we discuss the parameter sel
ection problem on the length of the training sequences in the subchannel al
location scheme in ,  by using the proposed ML detection algorithm.
The results show that the subchannel allocation scheme in ,  is feas
ible since only a few symbols overhead is required.