A UMTS Sector has 2 UARFCN?

[Onigece]

Why are there two UARFCN under each sector of a UMTS cell? These 2 UARFCN has the same scrambling code! Some says, one of these is for Release99 and the other one is for HSDPA, is this really the case? I am confused because unlike a GSM sector which only has a single ARFCN intended for its BCCH. I am an Optimizaton Engineer starter.

[Piojo]

Hi Ojigece,

Some operators use two carriers instead one over same sector for each umts cell. Each carrier have a different uarfcn, and may be or not have the same scrambling code.

If the operator has enough band width assigned to use, he can have more than one 5Mhz carrier for cell.

best regards,

[P.T.E.]

Dear,

in GSM you have Frequency planning so that you have different ARFCN/BCCH for each cell, while in WCDMA you have SC planning so that each cell has different SC, SC range from 0 -to-511, so for sure you will have SC reuse, and since WCDMA operate on one frequency all the time, you will fined that each UARFCN is related to one frequency (UARFCN = Freq*5).

Knowing that in one network you can deploy many frequencies (in my country we are using 4 carriers, one of them is U900), and they can be used in too many different scenarios, for example as you said, one Freq fore carrying CS, and other one for PS, can be used for load sharing, deep indoor coverage, DC-HSPA ..

BR,


Why are there two UARFCN under each sector of a UMTS cell? These 2 UARFCN has the same scrambling code! Some says, one of these is for Release99 and the other one is for HSDPA, is this really the case? I am confused because unlike a GSM sector which only has a single ARFCN intended for its BCCH. I am an Optimizaton Engineer starter.

[bino]

Why are there two UARFCN under each sector of a UMTS cell? These 2 UARFCN has the same scrambling code! Some says, one of these is for Release99 and the other one is for HSDPA, is this really the case? I am confused because unlike a GSM sector which only has a single ARFCN intended for its BCCH. I am an Optimizaton Engineer starter.

Hi,
In some cases, Operator uses 3 UARFCNs on 1 cell for enhance capacity.
May be 2 UARFCN have priority used for R99 and 1 UARFCN for HSPA.

[Andryawan]

In 3G, we use SC (Scrambling Code) to distinguish each cell in one site so no matter how much UARFCN you have in one cell (1 or 2 or 3 UARFCN), the SC is always same. If they have high traffic & enough bandwidth (UARFCN) they could implement 2nd carrier or 3rd carrier or more. It depends on operator for the strategy, they could to use one for R99 & another for HSDPA or other.

What you mean "a GSM sector which only has a single ARFCN intended for its BCCH", as far as I know, no matter how much ARFCN you have in one cell you you're still able to use 1 BCCH, cmiiw

[stiffq]

for 2 carriers it's Ok to use same PSC as the Freq are different so no interference issue and it's easy to do the PSC planning and ID the cell while testing

[Vladislav]

I am totally agree with you, it is better to assign same PSC to the collocated cells of one sector not to create a confusion for the future analysis and planning. This is just easy.
As for the several UARFCNs - adding of the 2nd or 3rd UMTS frequencies needed to increase the network capacity for serving more users and be avle to allocate more resources for them (especially power). All UARFCN can be used for all services or they can be allocated by the operator defined rules (for example: 1st carrier for R99, 2nd - HSDPA, 3rd - HSPA+).

[rabatcasa]

you add carrier in 3g to add capacity , each carrier will have 5 Mhz bandwith. the same thing is used in LTE where an operator can mix differnets bands/bandwith in the same sector for example 10 Mhz + 5 Mhz o5 10 Mhz + 3 Mhz

[dtvt2]

Hi all
- 1 UARFCN in 1 sector can support a limit speed: 14.4 (16QAM), 21 (64 QAM). All user will share this bandwith. If there are many users in the same sector their throughput will decrease. so you a UARFCN to increase end user speed. When you have 2 carrier the load will be balance between 2 carrier so Ec/No decrease -> speed increase
dtvt2

[patek1968]

F1 and F2 specifically balance the traffic load under a congested network..Same PSC even you have U900 co-located to avoid confusion and for better planning capacity.