Sometimes we say Ec/Io and sometimes we say Ec/No, are they different?

Io = own cell interference + surrounding cell interference + noise density

No = surrounding cell interference + noise density

That is, Io is the total received power density including CPICH of its own cell, No is the total received power density excluding CPICH of its own cell.  Technically Ec/Io should be the correct measurement but, due to equipment capability, Ec/No is actually measured.  In UMTS, Ec/No and Ec/Io are often used interchangeably.

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KPI Monitoring and Improving Guide