13 BIRTH–DEATH RANDOM PROCESSES

13.1 INTRODUCTION

Many random phenomena can be characterized in a state manner and with changes of states defining the nature of the phenomena. For the case where the states are integers, the state represents the population of a set of entities, and the population changes in integer steps according to births and deaths, a birth–death random process is defined.

The usual manner for characterizing a birth–death random process is via a sequence of differential equations that define the change in state probability with time. Results for important cases—constant birth rate and zero death rate processes, state-dependent birth rate and zero death rate processes, zero birth rate and constant death rate processes, and constant birth and constant death rate processes—are discussed. A constant birth and constant death process underpins the simplest queueing system—the M/M/1 queueing system (a first-come–first-serve queue with waiting and service times).

13.2 DEFINING AND CHARACTERIZING BIRTH–DEATH PROCESSES

13.2.1 Notation and Definitions

Fundamental to birth–death random processes are the following definitions.

Get A Signal Theoretic Introduction to Random Processes now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.