**3. Femtocell bandwidth requirement**

As been discussed in the previous section, femtocell utilizes the existing broadband IP access available in the customer home. As ADSL2/ADSL2+ has highest penetration rate compared to other fixed wireline access technologies, logically the initial femtocell deployment would have used this type of access. HSDPA Femtocell, for instance, has radio capacity about 7.2 Mbps downlink and 1.4 Mbps uplink. Low speed backhaul, as in Table 1, 146 Mobile Networks

The medium bandwidth category (3 – 10 Mbps in downstream direction) is usually used to accommodate IPTV, internet and hosted home video surveillance services. In the upstream direction, 1 Mbps line speed can be considered when the copper length can be maintained less than 600 meter from MSAN location. By this medium speed backhaul, we assumed more than 50% DSL subscribers in most European region can have this line speed. While in Jakarta, IPTV service is still emerging, however in term of the attainable rate, it will potentially cover 30% DSL penetration and it will further increase as the deployment of

Figure 7 illustrates the femtocell backhaul model based on the Table 1. In distance 4 km, backhaul quality will be limited. Theoritically ADSL2+ in 4 km can deliver 9 Mbps, however according to the real implementation it can only deliver 4-5 Mbps. By shortening the copper length using FTTC configuration where now copper length is maximum 1 km, the backhaul

High speed backhaul (up to 24 Mbps) is offered to the customer who requires more bandwidth in both downstream and upstream direction. Currently this type of backhaul addresses more than 23% of all fixed broadband in most European Region. Even though VDSL2+ can offer more than 30 Mbps data rate, the upstream data rate limits the overall performance. We limit the range of this backhaul type up to 800 meter distance in order to

**4 km**

**1 km**

**800m**

As been discussed in the previous section, femtocell utilizes the existing broadband IP access available in the customer home. As ADSL2/ADSL2+ has highest penetration rate compared to other fixed wireline access technologies, logically the initial femtocell deployment would have used this type of access. HSDPA Femtocell, for instance, has radio capacity about 7.2 Mbps downlink and 1.4 Mbps uplink. Low speed backhaul, as in Table 1,

**Backhaul Quality**

**Low : ADSL2/2+, DL 2 Mbps, UL 512 kbps**

**Med : ADSL2+, DL 10 Mbps, UL 1 Mbps**

**High: VDSL2, DL 24 Mbps, UL 2-5 Mbps**

**FTTH, 100 Mbps**

**CO Cabinet MDU Homes**

FTTC is progressing.

quality is much better.

**FTTC**

**PON**

Fig. 7. Backhaul Quality Model

**3. Femtocell bandwidth requirement** 

**FTTE**

**FTTC**

achieve 2-5 Mbps speed in the upstream.

cannot completely accommodate the HDSPA full buffer in the air interface, so there may be bottleneck in the xDSL link. However if operator carefully analyze the individual bandwidth and QoS requirement for the basic communication services such as voice, http, ftp and video streaming, one can still hope that even low speed backhaul is able to support femtocell.

During connected mode, the bandwidth required by a FAP depends on service or application. Each service has its own traffic behavior. The aggregate traffic from different users will determine the total traffic occupied by the femtocell. However, in case Indonesian mobile operators, where the market is very competitive, 3G packet data offerings are based on unlimited data schemes. The offering may vary from 64kbps, 128kbps, 384kbps, 1.8Mbps, 3.6 Mbps and 7.2 Mbps. The average bandwidth required by a FAP to support these offerings can be seen in Table 2. The bandwidth is determined in the backhaul interface both for xDSL and Ethernet. As it can be seen from the table, that unlimited data packages of 64kbps, 128kbps from four different UEs can be supported by low speed backhaul category (below 2 Mbps downlink, 512 kbps uplink, according to xDSL case as in Table 1). Offers providing up to 384kbps, 1.8 Mbps, 3.6 Mbps and 7.2 Mbps should consider medium to high bandwidth quality. The constraint will be in uplink streams if the offering is symmetrical between uplink and downlink.


Table 2. Femtocell bandwidth estimation over xDSL and Ethernet

Those connectivity data offerings are indeed valid for macrocell. The MBS has been designed to anticipate peak data rate by utilizing carrier class backhaul. In case of femtocell, the backhaul is depending on broadband connectivity subscription in the customer side. The worse case situation is that, the backhaul bandwidth may be far below supported peak data rate of associate radio technology (HSPA, WiMAX, LTE, etc). Therefore we propose more realistic bandwidth requirement for a FAP by observing the individual bandwidth consumption of selected services. For this purpose, we measured the bandwidth for 4-unitcalls FAP (FAP which supports 4 simultaneous calls) which is commonly used for residential femtocell deployment.

Femtocell Performance Over Non-SLA xDSL Access Network 149

xDSL Provider A xDSL Provider B

Fig. 9. Top 10 most visited internet content by subscriber of two ISPs in Indonesia

Real m.detik.com 4shared.com

facebook.com

detik.com & facebook.com

**HTTP File transfer Video** 

Real - - - AMR scenario 1

(5 MB)

4shared.com (13 MB)

4shared.com (13 MB)

Table 3. Summary of traffic mix for femtocell performance using xDSL as the backhaul

The applications are accessed through various UE types including, smartphone and tablet PC. It is assumed that each user accesses only one service type. The traffic traversing through a FAP is recorded by Femto NMS. For this purpose, xDSL profile is set to maximum (20 Mbps), so that the original bandwidth required to send traffic will go smoothly without any congestion or queuing in the access network. Since we use commercial GGSN, the traffic will be affected by the GGSN load, however we anticipated by using 3G SIM Card with the highest priority QoS profile defined in HLR/GGSN. Furthermore the individual test is

Real Detik.com FTP up to 40 MB youtube - Scenario 2

**streaming**

youtube 240x360p

youtube 240x360p

Video conference **Voice Notes** 

AMR scenario 1


AMR scenario 1, 2

**Traffic Mix Traffic** 

Mix Traffic Generated and Real

Smartphone mix 4 CS Call

Smartphone mix all traffic

Tablet PC mix all traffic

Background

PC

**Source** 

Real detik.com &
