2. SRM Institute of Science and Technology
Co-channel Interference
•All the cells using the same channel are physically located
apart by at least reuse distance.
•Even though the power level is controlled carefully so that
such “co-channels” do not create a problem for each other,
there is still some degree of interference due to nonzero signal
strength of such cells.
•In a cellular system, with a cluster of seven cells, there will
be six cells using co-channels at the reuse distance; this is
illustrated in fig below.
•The second-tier co-channels, shown in the figure, are at two
times the reuse distance apart, and their effect on the serving
BS is negligible.
3. SRM Institute of Science and Technology
Co-channel Interference
Fig .Cells with co-channels and their forward channel interference on transmitted signal
4. SRM Institute of Science and Technology
Co-channel Interference
•The co-channel interference ratio (CCIR) is given by
where Ik is the co-channel interference from BSk and M is the
maximum number of co-channel interfering cells. For cluster
size of 7, M = 6, CCIR is given by
5. SRM Institute of Science and Technology
Co-channel Interference
Fig. The worst case for forward channel interference (omnidirectional antenna).
