Approximate Solution of Optimal Frame Size in S-W ARQ Protocol of DLL

This paper considers the data transmission system with undulating noise and sudden noise. The quantitative relationship between the misuse frame rate and bit-error-ratio is derived. In this noisy channel, the connection-oriented protocol of data link layer is used to provide reliable delivery service for upper users. The calculation method and the approximate expression of optimal frame size in S-W ARQ protocol of data link layer are deduced in detail in the condition that the bit-error-ratio of channel is relatively small. Moreover, the physical meaning and the application area are also analyzed and discussed.