Ec/Io

[magno22]

Dears,
How to improve Ec/Io in WCDMA network?
I think missed neighbors can affect Ec/Io. So i added all of missed neighbors and increase antenna downtilt. But still i have interference and RSCP is good. What i need to do?

[Philippe]

Have you identified any pilot pollution? from overshooting sites?
How much is your Ec/Io?

[magno22]

Have you identified any pilot pollution? from overshooting sites?
How much is your Ec/Io?

Ec/Io is lower than 14. Monitored set quantity is mostly more than 6 bus active set and first monitored set signal difference is 10dBm. How about this?

[ninjafine]

Hi, Magno! You may try few things:
1 - check if cpich power is strong enough;
2 - make measurements at busy hour and at hour without load. If it is mostly correlated with load add additional carrier;
3 - lock co-site cell and measure Ec/Io again.

[shishio]

you have good RSCP with 10dbm margin but poor EcIo and interference.......check your cell DL load and number of users it seems to me your cell has a lot of users who are raising the noise floor of the surrounding area, solution
1. add 2nd carrier
2. reduce cell coverage area (downtilt or reduce Cpich power)
3. share traffic of congested area with nearby cells through physical optimization (this might be difficult since the nearest other cell has 10dbm power difference)
4. reduce number of maxretransmit
5. reduce UE max transmit power

add rep (black star below this post to the left) if this is useful

[Alex_R]

You can check data utilization in order to add 2nd carrier if needed.
check Radio Link replacement event as it may be the cause of pilot pollution

[dtvt2]

you can check
- SC collision
- DL load
- Down tilt

[magno22]

you can check
- SC collision
- DL load
- Down tilt

Dear,
Can you explain me DL load how to affect Ec/Io?

[rnpopt]

Dear,
Can you explain me DL load how to affect Ec/Io?

Hi Magno22,
Ec/Io is the ratio of Pilot Channel Power to Total Power (Pilot Channel Power/Total Power). Here total power is : Pilot Channel Power+Other common channel power+Traffic channel Power.

Now see example below:
Case 1- No Traffic:
Pilot channel power = 2W, Other common channel Power = 2W, Traffic Channel Power = 0 ; So Ec/Io = 2/(2+2+0) = -3 dB

Case 2- With Traffic:
Pilot channel power = 2W, Other common channel Power = 2W, Traffic Channel Power = 4W (for example) ; So Ec/Io = 2/(2+2+4) = -6 dB

So, you can see, with the increase in traffic, the Ec/Io degraded.

[Philippe]

Hi Magno22,
Ec/Io is the ratio of Pilot Channel Power to Total Power (Pilot Channel Power/Total Power). Here total power is : Pilot Channel Power+Other common channel power+Traffic channel Power.

Now see example below:
Case 1- No Traffic:
Pilot channel power = 2W, Other common channel Power = 2W, Traffic Channel Power = 0 ; So Ec/Io = 2/(2+2+0) = -3 dB

Case 2- With Traffic:
Pilot channel power = 2W, Other common channel Power = 2W, Traffic Channel Power = 4W (for example) ; So Ec/Io = 2/(2+2+4) = -6 dB

So, you can see, with the increase in traffic, the Ec/Io degraded.

Taking into acccount extracell interference in your calculation, this leads to:
- Ec = 10% Pmax power / pathloss, generally Pilot power is dimensioned for 10% of max power (e.g. 33 dbm for 43dBm (20W) output power)
- Iintra = X% Pmax power / pathloss , X% is the power load, if only common channels are transmitted (no traffic) this means around 20% of max power is transmitted.
- Iextra = F Intra, where F is the ratio of extracell vs intracell interference. Close to the NodeB, F is low close to 0. At cell edge, F is close to 2 (e.g. you receive quite same power from your cell and 2 surrounding cells so F=2),
- NoW = Noise level (typically -100dBm).

Ec/Io = Ec/ (Iintra+Iextra+NoW)

Imagine noise level (NoW) is neglectible compared to Intra+Iextra, Ec/Io = Ec/ (Iintra+Iextra) = 10% / [(1+F)*X]

If F=2 at cell edge, Load X = 20% (only common channels), Ec/Io = -7.8dB
If F=2 at cell edge, Load X=100% (all power used by common channels and traffic channels in all the cells), Ec/Io = -14.8dB