Using total transmission time-the time needed to guarantee reliable data dissemination——as judgment criterion

the payload length selection problem was investigated for three multicast solutions which are based on simple feedback retransmission

Reed-Solomon codes

and LT fountain codes

respectively

with the consideration of packet overhead.A theoretical analysis method was proposed to determine the optimal payload lengths

which was verified by simulations.Analyses and simulations indicate

for variable packet overhead sizes and link bit error rates

each method considered has its optimal payload length.As link bit error rate increases

the performance gain brought by the selection of optimal pay-load lengths becomes more significant.Among the three solutions

the reliable multicast solution based on LT fountain codes has the most outstanding performance.