Electronic Communication Systems 2nd Edition by Roy Blake

Exercise 45

Suppose that a system's customers use their cell phones for an average of 5 minutes each during the busiest hour. The system has 10,000 customers, approximately evenly distributed over 100 square km. Half of the customers have dualmode digital phones. The other half have analog-only phones. We require a maximum of 2% call blocking for those with digital phones at rush hour.
(a) How many cells are required and with what radius, if we choose an analog system with a twelve-cell repeating pattern Assume hexagonal cells.
(b) Suppose we try to improve service by changing to a digital system, leaving one analog channel per cell. What happens (qualitatively) to the blocking rate for customers with each type of phone
(c) How could we improve the situation in (b), as it applies to analog-only customers