But FDM is risky for multipoint, multiport applications because of its susceptibility to adjacent-channel interference when line conditions are less than ideal.
Adjacent-channel interference results when varying individual channel strengths from multiple drops interfere with each other, inhibiting the ability of the modem to distinguish noise from data.
It combines several channels over a single, wider band to eliminate the potential for adjacent-channel interference and its consequent error-performance and throughput problems.
In today's wireless networks, where protocols such as GSM, GPRS and Edge are prone to interference, precise identification of co-channel and adjacent-channel interference
is crucial in cell and frequency planning and network optimization.