Statistical characteristics of bit error occurrence on digital radio channels

Some statistical characteristics of transmission errors associated with a digital radio channel in the absence of protection switching are examined. It is demonstrated that the occurrence or nonoccurrence of bit errors in an unprotected digital radio channel is a dependent stochastic process. Additionally, it is shown that the distribution of the number of errored seconds in a given time interval depends upon the cause of the errors. Multipath fading, for example, will cause equal numbers of severely errored seconds and nonseverely errored seconds. On the other hand, equipment failures and maintenance activity cause more severely errored seconds than nonseverely errored seconds. These signature characteristics are related to the lack of independence in the occurrence of bit errors in adjacent seconds. The results discussed have important implications in the development of performance models for digital radio. In particular, they demonstrate the need for a controlled experiment dedicated to the study of the correlation structure that governs the occurrence of bit errors