question: What is the general framework for precoding with reciprocity? option 1: Reverse link training, forward link training, convergence, data transmission option 2: Forward link training, data transmission, reverse link training, convergence option 3: Forward link training, reverse link training, convergence, data transmission option 4: Reverse link training, data transmission, forward link training, convergence option 5: Convergence, forward link training, reverse link training, data transmission 