Apparatus and methods for wireless communication include receiving, in a time division synchronous code division multiple access (TD-SCDMA) network, a first number of symbols before a midamble, the midamble, and a second number of symbols after the midamble; determining first forward and backward probabilities for a first subset of the first number of symbols and second forward and backward probabilities for a second subset of the second number of symbols; determining first posterior probabilities for the first subset of the first number of symbols and second posterior probabilities for the second subset of the second number of symbols; determining a first target posterior probability and a second target posterior probability; detecting a first target symbol and a second target symbol; and determining a first channel estimate corresponding to the first target symbol and a second channel estimate corresponding to the second target symbol.