Subject : Mobile Communication

Topic : Emerging Technologies

Difficulty : Medium

Frequency Reuse: It is the process in which the same set of frequencies can be allocated to more than one cell,provide the cells are at a certain minimum distance apart referred to as frequency reuse distance.The design process of selecting and allocating channels groups for all of the cellular base station within a system is called Frequency Reuse or Frequency Planning.

Diagram:

Co-channel interference: Cell which uses the same set of frequencies are referred to as co-channel cells.In the above figure co channel cells are labelled with same name such as A,B,C - - - - F. The space between adjacent channels is filled with other cells that use different frequencies to provide frequency isolation.If the system is not properly designed co-channel interference may occurs due to the simultaneous use of the same channel.Specifically if the available channels are reused for additional traffic,it is possible to serve more number of users.Frequency channels are allocated to each cell by means of an intelligent frequency planning technique so as to minimize the co-channel and adjacent channel interference while meeting the performance requirements both in terms of received signal quality as well as traffic capacity in these cells.

Advantages of frequency reuse:

• Large coverage area
• Efficient spectrum utilization
• Enhanced system capacity