  This paper proposes a data-unit-size distribution model to represent the
retransmitted packet size preservation (RPSP) property in a scenario where
independently lost packets are retransmitted by a stop-and-wait protocol. RPSP
means that retransmitted packets with the same sequence number are equal in
size to the packet of the original transmission, which is identical to the
packet generated from a message through the segmentation function, namely,
generated packet. Furthermore, we derive goodput formula using an approach to
derive the data-unit-size distribution. We investigate the effect of RPSP on
frame size distributions and goodput in a simple case when no collision happens
over the bit-error prone wireless network equipped with IEEE 802.11 Distributed
Coordination Function, which is a typical example of the stop-and-wait
protocol. Numerical results show that the effect gets stronger as bit error
rate increases and the maximum size of the generated packets is larger than the
mean size for large enough packet retry limits because longer packets will be
repeatedly corrupted and retransmitted more times as a result of RPSP.
