DSL - Video service based on VDSL
VDSL offers operators the possibility of offering a multitude of digital video service which increases their telephony offerings and existing internet services. VDSL has the ability to support digital television broadcasting, video on demand and HDTV over standard twisted pair copper.
In addition to digital video and Internet services, VDSL also supports interactive video services, web television, e-commerce, video conferencing and video games, a set of services currently not available from cable operators or DBS.
High Speed Internet
Providing high speed Internet access is a core value for individuals, small businesses, hotels, institutions and other multi-site buildings. The internet is growing at a phenomenal rate and this growth is here.'expansion of new and varied applications to take advantage of the increased availability of equipment, software, access and users. These new applications require more resources than what can be provided with the existing infrastructure, which limits the potential for profit in providing these applications.
While other DSL technologies such as ADSL and G.lite , can meet the limited requirements of current Internet applications. These systems will soon run out of bandwidth. However, VDSL has the ability to support the applications of today with the emerging applications of tomorrow, creating new opportunities for revenue growth, while preserving investments in DSL technology. by ATM. ATM technology is the preferred FSAN Internet backbone to handle the growing load of supporting daily operations and Cree applicationsticks. The ATM architecture was chosen because it allows a single ATM network to be used to support all data, voice and video transports instead of delivering them to separate and incompatible networks. The combination of VDSL and ATM technology provides Internet services today in an architecture that supports the applications of tomorrow.
A key service for every operator is the provision of vital telephony services. One thing that has become universally expected is that no matter what, the phone will work. VDSL, like other DSL technologies, supports a lifeline POTS connection. This is a basic requirement that must be met by a telephony service provider. VDSL provides this functionality and gives the carrier the ability to provide additional voice channel derivatives over the same existing copper pair.
Voice over IP (VoIP) and voice over ATM technologies (VToA) provide standard quality telephony services over a digital network . Since ATM can also carry IP-based communications, ATM over VDSL will support both digital telephony standards. Although Voice over DSL (VoDSL) initiatives seek to develop a transport standard on the flavors of DSL, bandwidth is still the issue. Higher bandwidth VDSL provides more derived voice channels.
Cable operators are beginning to enter the voice market using these technologies, but they face a major hurdle in providing Lifeline services . The ability of the new class of full-service telecommunications operators to deliver essential POTS services alongside telephony, Internet access and digital video derivative services is a major advantage.Major age compared to cable and DBS operators.
The full service access network deployment is progressing with the deployment of fiber networks. The final architecture is fiber to the home and business, but implementation will take a number of years and significant resources.
Today 's deployment scenarios are fiber-to-commerce (FTTEx), fiber to the neighborhood ( FTTN), FTTCab and FTTB . VDSL is only suitable for FTTEx, where customers are served within easy reach of the central exchange (CO). FTTN and FTTCab are suitable for stand-alone deployments, at the VDSL switch, or as part of a new digital loop Carrier Generation (NGDLC).
FTTB would bring fiber directly into a building such as a multi site unit (MDU) or corporate enterprise and end VDSL.
Major VDSL2 activity
Here iscountries that use VDSL2.
- Currently 100 / 100M 5 band 100 / 50Mbps and 30MHz VDSL deployments are occurring in high volume at NTT , UCOM and KDDI. Field tests by Softbank of FTTN VDSL systems are also underway.
- CHT 5 Band 100/50 Mbps 480k VDSL is being deployed.
- Actively deploying QAM VDSL for over three years. Over 75% country coverage with ADSL and VDSL. VDSL2 will begin testing 30 MHz - 100/100 systems in September.
- SBC Lightspeed project will bring IPTV through the systems FTTN VDSL to over 4 million homes over the next three years.
- Verizon is deploying fiber to the premises (FTTP) and fiber to the cabinet (FTTCab) now. VDSL to multiple dwelling unitss will have some volume in 2006.
- VDSL systems field testing from BellSouth. Bell South and AT&T are now expected to merge and therefore have a common VDSL BBA strategy around VDSL2.
- Currently, Swisscom and Belgacom VDSL deployments are currently taking place in small volumes.
- Deutsche Telecom 17MHz deployments pending pending system issues.
- KPN and Telefonica deployed VDSL in 2007.
- Telecom Italia is being evaluated in the laboratory with the DSLAM VDSL at present.
- PCCW in Hong-Kong won a tender for ATM VDSL deployments.
- China conducted its second VDSL lab test session.
- Singapore Telecom VD laboratory test SL2 systems are being deployed.nt.
VDSL access deployment models
The following illustration describes the VDSL access deployment models.
Key features of VDSL2
These are the key features of VDSL2.
- Identical to ADSL
- Bandwidth increased by 30 MHz (14x ADSL2 +)
- Up to 4096 tones (8x ADSL +!)
Worldwide Versatile Standard
- 8 profiles defined for different services
- Different bandplans for different regions
- Variety of PSDs to optimize spectral compatibility
- Integrated QoS features
- ATM and Ethernet payload
- Channel bonding for a range or an extended flow
VDSL2 - DMT (Discrete Multi-Tone)
The conceptof discrete multitone is - The frequency band is
ADSL2 / 2 + / VDSL2 8a, 8b, 8c, 12a, 12b, 17a = 4.3125 kHz
VDSL2 30a = 8.625 kHz
Locker number × Tone spacing = Locker frequency
For example - Bin 64 × 4.3125k = 276 kHz
The advantage of this is that, it adapts to the characteristics of the channel / loop.
Vocabulary - sub-channel = sub-carrier = tone = bin.
Individual bands in a frequency band plan are populated with the spectrum generated by one or the other technology. Here we will show a 998 use case plan for both QAM and DMT.
Downstream transmit power -
- Tx power in VDSL1 is limited to 14.5 dBm for CO deployment and 11.5 dBm for cabinet.
- Why do we need high power?
- Improve the range of high throughput.
- Reduce the impact of FEXT from ADSL.
- PSD level increase only in DS1.
High transmit power is only with 8M profiles, as defined in the following table -
| Profiles || Tx power (dBm) |
| 8a || 17.5 |
| 8b ||20.5|
| 8d || 14.5 |