Why hexagonal cell shape is perfect over square or triangular cell shapes in cellular architecture?

M.C.A. (Management faculty) (Semester-IV)

IT 42 : MOBILE COMPUTING

Time : 3 Hours Max. Marks 70

1. Instructions to the candidates:
2. Question no 1 and 8 are compulsory
3. Answer any three questions from remaining.
4. Neat diagrams must be drawn wherever necessary.
5. Figure to the right side indicate full marks.

Q.1) a) Why hexagonal cell shape is perfect over square or triangular cell shapes in cellular architecture? What is cell splitting? Why it is required. How it is done. [10]

Ans. The geographic area or cellular service area is divided into small hexagonal region called cells. It is the basic unit of a cellular system. These cells collectively provide coverage over larger geographical areas.



Hexagonal cell shape is perfect over square or triangular cell shapes in cellular architecture because it cover an entire area without overlapping i.e. they can cover the entire geographical region without any gaps.

Frequency reuse and cell splitting are two main concepts in cellular networks. Cell splitting is the process of dividing a larger congested cell into smaller cells. Each cell has its own base station with transmitter power and antenna height.



When the traffic in an area increases, larger cells are split into smaller cells so that frequency can be reused. By splitting the cell, the capacity of the system will be increased because availability of additional number of channels per unit service area is also increased. There are two types of cell splitting.

- Permanent cell splitting
- Dynamic cell splitting

In permanent cell splitting everything is planned before it is actually implemented for new split cell. The assigned frequencies, the transmitter power, traffic load etc. are considered before.

The implementation of dynamic cell splitting is difficult job. Dynamic cell splitting is done according to the utilization of dedicated spectrum and traffic load.