Broadband Access for All A Brief Technology Guide

Transcription

1 Broadband Access for All A Brief Technology Guide

2 02/22 Broadband Access for all A brief technology guide Executive Summary Contents 02 Executive Summary Always Best-Connected The End-User s Perspective Look at Access Networks Nokia Siemens Networks Expertise in Wireless and Wireline Access Technologies Choosing Your Broadband Strategy Abbreviations A historic opportunity awaits the communication industry in the years ahead a chance to connect most of the world using wireless and wireline technologies. We envisage that five billion people will be connected by 2015, the majority always on and enjoying broadband access. Broadband connections will be available just about anywhere in the world, across developed and growth markets. Today s wireline service already reaches some one billion households, and mobile networks connect close to three billion subscribers, with varied capabilities offering true broadband connectivity. But it will take more extensive use of wireless access and new wireline installations with improved performance to offer true broadband connectivity to five billion customers. Wireline delivers far higher data rates than wireless. The wireline user data rate is some 30 times that of wireless, with both evolving in much the same way. Applications such as IP TV have a healthy appetite for high data rates, so great in fact that only wireline solutions can satisfy it. But wireless access can deliver most other services, including small-screen mobile TV. Incumbent wireline operators traditionally leverage their legacy copper installations to offer broadband services with DSL to consumers. Growing end-user bandwidth demand dictates that fiber must be brought closer to the subscriber. The choices are fiber to the curb and fiber to the building, with the next step up being fiber to the home, or FTTC, FTTB, and FTTH for short. In any case, bandwidth-hungry applications like high-definition TV and corporate connectivity are sure to prompt operators to improve and renew wireline networks. Wireless technologies, in contrast, have a huge advantage they offer personal broadband access regardless of the user s location. That spells total mobility for nomadic and fully mobile use cases. What s more, if a region lacks wireline infrastructure, wireless can provide low-cost broadband coverage at far lower cost than new wireline installations. Especially in emerging markets, this makes wireless broadband access an attractive alternative for densely populated urban and sparsely populated rural areas. This white paper discusses today s wireless and wireline technologies and how they are likely to evolve. Wireless technologies will soon catapult data rates from one Mbps beyond 100 Mbps and boost efficiency in data delivery. This paper describes broadband wireless technologies positioning in terms of spectrum assets, and introduces current and coming wireline technologies. And it explains how to extend the capabilities of copper-based DSL access and how to deploy optical networks to boost user data rates beyond one Gbps.

3 03/22 Broadband Access for all A brief technology guide 1. Always Best-Connected The End-User s Perspective Wireline voice communication began changing the world in the early 20 th century, with wireless following suit in the century s closing decade. A concurrent revolution, the Internet, continues to refashion the working methods and lifestyles of a growing share of the world s population. Now for the first time in history the arrival of broadband access technologies in wireline and wireless networks promises seamless, all-over access to unlimited information and entertainment to consumers and business users. Users combine these technologies to stay connected at work, at play, everywhere, all the time. Always connected has become the mantra for many. Technologies and services have grown exceedingly complex, posing even more questions for end-users as well as for providers and operators. A myriad of services and gadgets confront the end-user. Which service can I use on which device? Do I need yet another account and password? Where and when can I use it? At home, on the move, abroad? And finally, how much does it cost? From end-users perspective, the use case is an intricate issue compelling them to weigh many considerations what, when, where, how, and how much: The user s view of factors affecting broadband access Considerations Options Wishes...which service... Voice, data, entertainment services; Freedom of choice, Delivery: Machine-to-user, peer-to-peer; Flexibility Type: Personalized, off-the-shelf; bundles, triple/quadruple play...at home... Devices: Mobile phone, POTS/ISDN phone, Full range of services laptop/desktop, cameras, TV set, and the like available on best-suited devices with fewest subscriptions...at the office... Mobile phone, desktop phone, High reliability, security, laptop/desktop PC, and performance of basic corporate IT connectivity IT tools...on the move... Using personal devices Seamless access to key (such as phone, PDA, notebook); services with fewest At hotspots, in cars, trains, aircraft, walking, devices remote location, indoor and outdoor environments...with which Data rate, delay, user friendliness, reliability, security Speed, ease of use user experience (performance)......at which price... Base price, minute prices, bundle packages, Inexpensive, transparent flat rate, price transparency and controllable pricing

4 04/22 Broadband Access for all A brief technology guide The ideal solution is an environment enabling the end-user to enjoy always best-connected service with minimum, easy-to-use equipment. Though the demand for services hinges on the given market, there are three major classes. First is voice communication, the traditional revenue source. Second come data services such as high-speed Internet access. Finally, mature markets are seeing growing demand for applications and entertainment services delivered across the net, for instance, video on demand and time-shifting-enabled, interactive TV. As services grow richer and more varied, bandwidth consumption and user expectations for quality rise accordingly. Broadcasts over multiple high-definition TV channels, highquality video delivery, and video communication are just a few cases in point. New entertainment services like virtual-world gaming, where players assume a virtual persona in the reality represented in the games, are in the pipeline. And business subscribers need VPNs with differentiated service level agreements, video conferencing, and backup to the company s server. Besides, users want to go mobile with all the services delivered today over their wireline connection. Aiming to stay always connected, they want access to diversified content wherever they go. And though expectations for bandwidth and quality are on the rise, revenue per user is on the decline. Subscribers are unwilling to pay more for higher bandwidth and higher quality services, but operators must invest in new networks to prevent churn. This is a balancing act. Operators must minimize operational costs and choose the right technologies to build converged networks that provide the bandwidth pipes and mobility to deliver content and applications. The key to striking this balance is the interface between the subscriber and core network the access network. 2. Look at Access Networks Access networks connect end-user s devices to the network core and content and application servers. They cover the first mile to the subscriber and the second mile, where traffic is handled and the various services are aggregated and distributed. The first mile connects the subscriber s fixed or mobile terminal to the first access node, say a DSLAM, base station, or the like, and provides the bandwidth pipe to the subscriber. The transport medium for mobile access is the radio interface, better known as air. For wireline access, it is copper or fiber. Maximum bandwidth per subscriber varies according to several determinants the number of subscribers connected to the access point, the distance between the subscriber terminal and the access point, and the actual transport medium and its transmission frequencies. First-mile access technologies provision bandwidth and distribute services and applications individually to each subscriber. The second mile aggregates several first-mile access nodes and connects to the network core, which is called backhauling. Several technologies serve to aggregate access nodes. In modern networks, most base on the Ethernet protocol and use fiber as the transport medium. Legacy aggregation technologies such as ATM and TDM-based SDH and

5 05/22 Broadband Access for all A brief technology guide multi-service provisioning platforms as well as wireless microwave radio technologies are also widespread. Aggregation networks must meet carrier-grade standards, meaning that they are highly reliable and available, and support different quality of service classes. They must shuttle traffic to and from the access node effectively and cost-efficiently. And they must support various tariff schemes such as volume tariffs and flat rates. Today the state-of-the-art solution for the last meters within a building is a mix of wireline first-mile and wireless last meters, say, to connect wireline DSL and wireless terminals and home devices. Local access point solutions thus extend wireline access lines to wireless end-user equipment. Figure 1 shows the main network elements mobile or fixed end-user terminals, wireless base stations, wireline first-mile access nodes, aggregation networks, and the packet core network. The picture at the top shows where wireless solutions fit best; below it is the scenario where wireline solutions are a better match. The area between the two shows end-user service scenarios that may be served by wireline and wireless solutions. The following chapters examine the various access technologies in detail. Wireless Broadband Access Network Small, personal user device A Packet core network Internet B B Operator services A First mile access node Aggregation network C Corporate network Stationary, shared devices Wireline Broadband Access Network A B C High data rate capacity to the end user High capacity and low opex transport Second mile aggregation and scalability Challenges Figure 1: A look at broadband access

6 06/22 Broadband Access for all A brief technology guide 3. Nokia Siemens Networks Expertise in Wireless and Wireline Access Technologies Nokia Siemens Networks offers a complete and comprehensive portfolio for wireline and wireless access geared to satisfy the diverse end-user and market demands. The following section describes these requirements. 3.1 Wireless Technology Portfolio Licensed spectrum is the mobile operator s valuable asset the lower the frequency band (cell size) and the larger the band (cell capacity), the higher its value. Paired spectrum served by Frequency Division Duplex (FDD) technology makes up the lion s share of licensed spectrum today. Time Division Duplex transmission (TDD) serves the 2.5 GHz and 3.5 GHz range, where the uplink and downlink share the same spectrum. Making the most of available spectrum requires radio technologies for FDD and TDD bands. Mobile operators with UMTS and/or GSM bands need a broadband technology for the FDD spectrum. In Nokia Siemens Networks view, the primary global solution is HSPA and its evolution to LTE, and Mobile WiMAX e is destined to become the TDD technology for 2.5 GHz and 3.5 GHz bands. A wireless solution s coverage area is significant because it determines the number of base stations, the investment they entail, and the quality of indoor coverage. Figure 2 shows base station coverage area as a function of deployment frequency in a suburban application. The chart features two cases outdoor only, and with 15 db indoor penetration loss. Note that it takes nearly four times as many sites to deploy at two GHz than at one GHz, and ten times as many for 3.5 GHz. With capital expenditure in mind, deploying radio technologies at low frequency bands is preferable. On the downside, lower frequencies have less bandwidth capacity. So, the best deployment strategy combines low band for greater coverage and high band for greater capacity. Fixed outdoor antennas at the subscriber s end can increase network coverage considerably. BTS coverage area [km 2 ] Larger cell at lower frequency Larger cell if only outdoor coverage Outdoor only coverage Indoor coverage with 15 db penetration [GHz] Figure 2: Base station coverage area as a function of deployment frequency Note: The actual coverage area also depends on the environment and bit rate requirements

7 07/22 Broadband Access for all A brief technology guide GPP Broadband Access (HSPA, I-HSPA, LTE, EDGE) The High-Speed Downlink Packet Access (HSDPA) air interface enables true broadband access with more than one Mbps per subscriber and one Gbyte per subscriber per month. Most of the over 150 commercial UMTS networks have been upgraded to support HSDPA with peak data rates of 3.6 to 7.2 Mbps. The uplink counterpart providing peak data rates up to 2.0 Mbps, High-Speed Uplink Packet Access (HSUPA), is destined for rollout within HSDPA data use has already topped voice traffic in some instances, signaling that customers value ubiquitous broadband data. Nokia Siemens Networks offers full HSDPA 14.4 Mbps downlink capability and full HSUPA 5.76 Mbps uplink capability. HSPA networks up and running today feature 3GPP Release 5 HSDPA and Release 6 HSUPA. Figure 3 tracks the further evolution of the 3GPP standard. Release 7 HSPA Evolution leverages major radio improvements to reduce setup time, boost data rates, and deliver better performance to the user. It also improves spectral efficiency and mobile power consumption. These enhancements are collectively called HSPA+. Applying MIMO, release 7 boosts the peak data rate to 28.8 Mbps. By additional application of 64QAM, release 8 provides for an upward potential to 43.2 Mbps, while reducing latency to less than 30 ms. 3GPP Release 7 solutions are another step forward in bringing HSPA capabilities up to the objectives of 3GPP s Long Term Evolution (LTE), paving a smooth evolutionary path towards LTE end-user performance. 3GPP wrapped up the work on Release 7 in the first half Nokia Siemens Networks is committed to bringing the benefits of Release 7 to HSPA networks with a remarkably cost-efficient software upgrade. 3GPP R5 3GPP R6 3GPP R7 3GPP R8 HSDPA HSUPA HSDPA Further HSPA 14.4 Mbps 5.76 Mbps 28.8 Mbps and evolution up to HSUPA 43 Mbps 11.5 Mbps IP transport Multimedia I-HSPA flat LTE scalable broadcast architecture bandwidth multicast (MBMS) MHz EDGE evolution up to 1.4 Mbps Most featurerich 3GPP release since R99 Figure 3: The development of 3GPP wireless broadband technologies Specified as part of 3GPP Release 8, LTE will extend radio capabilities even further. With a peak downlink data rate up to 173 Mbps and less than 10 ms latency, it will deliver the best wide-area radio performance for the decade ahead. With its high data rates, low latency, high capacity, and large-area coverage, LTE will allow operators to use spectrum flexibly with various bandwidths and frequency variants, and terminals power to be managed efficiently. 3GPP intends to complete the first set of specifications in the first half of These peak data rates are available in parts of large macro cells coverage area. Cell interference and network planning impacts the actual average cell capacity. Broadband technologies spectral efficiency typically amounts to one to two bps per Hz per sector. If an operator has 20 MHz allocated for the downlink, average downlink throughput comes to 20 to 40 Mbps per sector. Beam-forming solutions and small cell deployments can improve wireless technologies spectral efficiency. Long term evolution (LTE): New radio with peak rate of 173 Mbps

8 08/22 Broadband Access for all A brief technology guide Although new high bit-rate technologies are driving data traffic in mobile networks, operators must cut data delivery costs to offer competitive flat-rate charging. New broadband HSPA, WiMAX, and LTE radio technologies slash the high cost of data delivery associated with earlier radio networks. Leveraging streamlined network elements in radio and core networks, their high radio performance, effective transport, and flat network architecture up efficiency. And that makes operators more competitive. 3GPP Release 7 HSPA architecture, I-HSPA, uses the same flat architecture as LTE and WiMAX. This cuts the cost of building network capacity today and paves the most future-proof path to tomorrow s LTE for HSPA operators. This flat architecture is compatible with legacy Release 5 HSDPA terminals. EDGE (Enhanced Data Rates for GSM Evolution) delivers real-world data rates ranging from 120 to 160 kbps, covering large areas and providing extensive terminal support. With 718 GSM networks up and running in more than 200 countries worldwide (GSA April 2007), GSM technology is on firm footing, providing the underpinning for the EDGE data solution. EDGE features in 258 networks in 136 countries (GSA January 2007). It can extend HSPA/ WiMAX networks coverage to encompass areas where HSPA/ WiMAX has yet to be built. EDGE is also an enabler for an extensive global roaming network. Evolution to operators running EDGEenabled networks, leveraging software upgrades to add its new features to existing GSM BSS IEEE WiMAX Broadband Access Fixed WiMAX d is certified and commercial products are available from Nokia Siemens Networks today. It offers an alternative to wireline ADSL for areas in which ADSL is unavailable and carriers are unable to deliver wireline broadband costefficiently. WiMAX d provides Frequency Division Duplex (FDD) support for the 3.5 GHz band. Mobile WiMAX e is looking to be the best-positioned Time Division Duplex (TDD) technology for fixed, nomadic, and mobile access aimed for the 2.3, 2.5, and 3.5 GHz bands. WiMAX carrier bandwidth ranges from five to ten MHz, and may later be extended to 20 MHz. Mobile WiMAX offers 40 Mbps peak bit rate with ten MHz bandwidth, and up to 80 Mbps with 20 MHz. A standardized broadband access technology, it is backed by many network and terminal vendors, creating a global ecosystem and a future-proof way of offering mobile broadband. Driven by economics of scale and interoperability between vendors, the WiMAX market is also evolving from fixed WiMAX d to mobile WiMAX e for fixed applications. Nokia Siemens Networks offers certified WiMAX e products. 3GPP Release 7 encompasses EDGE Evolution, which pushes the peak data rate up to 1.4 Mbps. Legacy EDGE networks operating in GSM frequency bands may be upgraded with these evolutionary features. EDGE Evolution plays an important role in complementing HSPA networks and boosting global wireless data capabilities. Nokia Siemens Networks is committed to bringing the benefits of EDGE

9 09/22 Broadband Access for all A brief technology guide Other Radio Technologies from Nokia Siemens Networks Many other radio technologies beyond 3GPP HSPA/LTE and WiMAX in Nokia Siemens Networks portfolio cater to specific customer needs. Defined in 3GPP Release 4, TD-SCDMA radio technology bases on TDD technology and targets the Chinese market. It is also known as low chip-rate or narrowband TDD mode. An FDD technology for operators with access to the 450 MHz spectrum, FLASH-OFDM employs large cells to deliver mobile broadband services nationwide at low capital expenditure. In commercial use today, it is an attractive alternative for deploying broadband services on narrowband niche spectrum allocations. This mobile broadband access solution has also proven its merits as a backhaul solution for WiFi hotspots in buses and high-speed trains. WiFi ships as a standard appointment on new notebooks, and the range of mobile terminals and PDAs equipped with WiFi is growing. Today s WiFi devices base on the b and.11g standards, and are expected to evolve to n, bringing peak data rates to 200 Mbps and beyond. Often used indoors, WiFi may also be deployed in public metropolitan areas in the unlicensed 2.4 GHz and 5.4 GHz spectrum. Seeing the widest use in North America, Metro Wifi has proven its merits in providing outdoor coverage in urban areas. Some issues concerning indoor coverage and transport costs have yet to be resolved. Meshed WiFi entails connecting clusters of access points to a backhaul network for fewer interconnections and significantly lower transport costs. WiFi uses unlicensed spectrum, so interference from other local equipment in the same spectrum may affect actual WiFi performance Cdma2000 Data Evolution Currently just over 10 percent, cdma2000 s share of the global mobile subscriber market has been ebbing since To enjoy the benefits of a large, open ecosystem and economies of scale for low-cost mobile devices, many major cdma operators are turning to GSM/WCDMA for future voice services. Theoretically providing peak rates up to 3.1 Mbps on dedicated data carriers, the cdma data solutions EV-DO Rev.0 and Rev.A have been deployed commercially. For future data services, many cdma operators are looking at HSPA or WiMAX for the short term and 3GPP LTE for the long term.

10 10/22 Broadband Access for all A brief technology guide Mobile Terminals What It Takes for Technology to Succeed End-users buy attractive packages of services and terminals, not radio systems. So a radio system s success hinges on the availability of a large selection of low-cost terminals. Nokia Siemens Networks provides end-to-end wireless solutions encompassing a wide range of Nokia devices. Terminals, above all, drive the success of GSM technology for the voice market. With HSPA capability destined to soon become a standard feature on all 3G terminals, widespread availability of HSPA terminals is expected to drive data use. More than 300 HSDPA-enabled devices, ranging from embedded HSDPA chips in laptops to multimedia computers and mobile terminals, have already been launched. WiMAX terminals will be available Nokia is committed to making WiMAX-enabled multimedia computers and tablets available. While mobile terminals outnumber notebooks tenfold, the latter can easily generate ten times the former s packet data traffic. This means integrated radio technologies availability in notebooks will have a major impact on data volume and network size. Integrated HSPAbased notebook radio solutions are widespread today, and integrated solutions based on WiMAX will soon become available. Notebooks and Internet tablets larger form factor may make them more suitable terminal platforms than traditional mobile phones for deploying advanced antenna systems such as MIMO, designed for HSPA Evolution, WiMAX, and LTE The Backhauling Challenge in Wireless Technology Base station transport traditionally used TDM (E1, T1) lines, each providing 1.5 to 2.0 Mbps capacity. Though acceptable for voice and low data rate applications, E1 capacity is inadequate for higher wireless data rates. Figure 4 shows the peak data rates of selected wireline and wireless technologies. On the left are downstream peak data rates; on the right, upstream peak rates. HSPA and WiMAX networks can use DSL technology for backhauling. And DSL-based transport solutions can provide higher data rates. They are also a far less costly means of data delivery than deploying multiple E1 lines. To provide peak data rates, 160-Mbps Long Term Evolution (LTE) requires highspeed broadband access such as point-to-point Ethernet or passive optical networks (PON). The wireline solutions described in Section 3.2 are also used effectively for wireless access backhauling. Microwave radio links today account for more than 50 percent of wireless access transport solutions. Their advantage is flexibility and fast rollout, coupled with significantly lower network operating expenditure. Latestgeneration microwave radios also use bandwidth more efficiently by taking a hybrid approach to backhauling Ethernet traffic alongside TDM (E1, T1) and multiplexing non-real-time packetbased traffic statistically. New technologies enable microwave links to extend transport capacity to 180 Mbps in 28 MHz RF bandwidth, which means operators can host a growing volume of data with the same RF spectrum license. Microwave remains the only alternative where geographical and economic constraints preclude the use of wireline transmission media.

11 11/22 Broadband Access for all A brief technology guide Peak data rate 10 G 1 G Downstream / Downlink Ethernet GPON Upstream / Uplink Ethernet GPON 100 M VDSL2 with DSM L3 VDSL2 LTE WiMAX VDSL2 with DSM L3 VDSL2 LTE 10 M 1 M ADSL2+ ADSL SHDSL.bis E1 HSPA EDGE evolution SHDSL.bis ADSL2+ E1 ADSL WiMAX HSPA EDGE evolution 0.1 M EDGE EDGE Very high data rate solutions beyond 100 Mbps High data rate solutions beyond 10 Mbps Voice and low data rate solutions Figure 4: The development of wireline and wireless data rates 3.2 Wireline Technology Portfolio Wireline broadband access great advantage is its ability to concurrently deliver highest data rates to many subscribers. It paves the way for several new services such as IPTV and high-definition TV (HDTV). The broadband packet network allows business customers to enjoy virtual private networks (VPNs) as well as peer-to-peer file sharing. Operators can reuse copper phone lines to easily offer high-bandwidth broadband access and enrich their service offerings without investing in new transmission media. However, although engineers are making great progress in extending DSL s per-subscriber reach and bandwidth, they will eventually arrive at copper s physical limits. Fiber can cope with constantly growing bandwidth demand, and FTTB and FTTH are sure to become the architectures of choice for future broadband access networks. Figure 5 outlines a wireline access network. Various first-mile technologies are available - digital subscriber lines, passive optical networks, point-to-point Ethernet, and multiservice access nodes that combine these technologies with classic voice service. Aggregation comes courtesy of Carrier Ethernet switches that connect many first-mile access nodes with backbone networks such as IP/MPLS networks, the PSTN, or radio network control. Though not covered in this white paper, other technologies such as SDH-based multi-service provisioning platforms, wavelength division multiplexing, and microwave radio are also options for metro aggregation.

12 12/22 Broadband Access for all A brief technology guide The following subsections summarize the technologies available for wireline access over copper and fiber Digital Subscriber Line (DSL) Although well known as the classic broadband access technology and delivered alongside phone service on twisted pairs of copper wire, DSL actually entails many technologies distinguished by data rates, reach, and application. A summary of the most significant follows. Voice over IP demanding 120 kbps can run in parallel on the ADSL link. ADSL lines span distances up to five km, enabling deployment from a central office. Copper loops in the downtown areas of many countries cities are some two km long, which translates to 16 Mbps. Continuing standardization efforts in ITU-T aim to further improve immunity against impulse noise. Nokia Siemens Networks DSLAMs offer ADSL line cards featuring ADSL2plus, ADSL2 and ADSL. ADSL/ADSL2/ADSL2plus (Asymmetric DSL, ITU-T G.992.1/3/5). The ADSL family is the most commonly deployed DSL technology, with up to 20 Mbps downstream capacity and peak upstream capacity of one to three Mbps. The downstream-to-upstream performance ratio of 10:1 is perfect for IPTV services with high downstream data rates and highspeed Internet browsing. DSL modem xdsl BTS / Node B Mobile network control RNC/BSC Mobile access DSLAM Broadcast TV PON SFU Video on demand Middleware Media content provisioning OLT High-speed Internet MDU IP Edge Ethernet IPTV, VoD BRAS Splitter Access switch Ethernet NT IP/MPLS Backbone L2 CET Backbone Aggregation switches POTS/ISDN POTS/ISDN End user customer premises PSTN MSAN First mile access Figure 5: A schematic view of the wireline access network Metro aggregation Edge / Core Voice gateway Softswitch

13 13/22 Broadband Access for all A brief technology guide SHDSL/SHDSL.bis (Single-pair High-Speed DSL, ITU-T G.991.2). SHDSL s upstream and downstream capacities are equal. Its peak capacity is 2.3 Mbps at up to five km loop length, which may be multiplied by using regenerators. Enhancing the SHDSL standard, SHDSL.bis offers up to 5.7 Mbps downstream and upstream. Bonding several lines can multiply these rates to N x 5.7 Mbps. Nokia Siemens Networks DSLAMs cover both SHDSL and SHDSL.bis. With upstream and downstream performance being equal, SHDSL/ SHDSL.bis is best suited for business applications (peer-topeer file sharing) and mobile backhauling. Data rate [Mbps] VDSL2 VDSL2 with DSM L3 ADSL2plus ADSL2 SHDSL.bis High data rate VDSL2 with DSM L3 is expected to double legacy VDSL2 data rates and thus to increase reach VDSL2 offers the largest bandwidths at shortest loop lengths in both asymmetrical and symmetrical modes of operation ADSL2plus offers high downstream bit rate up to 3 km after that, it behaves the same as ADSL2 ADSL2 can operate at up to 5 km depending on loop conditions and noise interference SHDSL.bis offers symmetrical services at long distances from the central office Long loop Achieving up to 100 Mbps in either direction, VDSL2 (Very high-speed DSL, ITU-T G.993.2) is the solution for today s bandwidth-hungry applications. Encompassing multiple high-definition TV channels, highspeed Internet access, and VoIP, it enables a true triple play experience. On the downside, it takes copper lines shorter than 500 meters, which is less than the average loop length in most of the world, to achieve data rates higher than 50 Mbps. This means VDSL2 DSLAMs must be brought closer to subscribers with FTTC architecture. FTTB, where VDSL2 runs over legacy in-house cabling, can further boost VDSL2 bandwidth up to 100 Mbps symmetrical. This ability to deliver very high, symmetrical bandwidth to subscribers is the enabler for true triple play services, peer-to-peer applications such as video sharing, and community services. And it harbors the greatest revenue potential. 1 km 2 km 3 km 4 km 5 km Figure 6: The downstream data rates of various DSL technologies Although the VDSL2 standard was approved in 2005, major efforts are still underway to further develop the technology. They aim mainly to improve VDSL2 s immunity against interference and mitigate crosstalk to boost data rates. The latter effort is referred to as Dynamic Spectrum Management Level 3 (DSM L3). Engineers expect to double the data rate and significantly extend VDSL2 s reach. Figure 6 shows how data rates depend on loop length. Line length

14 14/22 Broadband Access for all A brief technology guide DSL is the technology of choice for operators who are able to reuse telephone wiring. ADSL/VDSL uses the spectrum above POTS/ISDN, leaving phone service intact. Alternatively, ADSL/VDSL may be operated without underlying POTS/ISDN by unbundling services. Competitive local exchange carriers can then tap new business opportunities by offering voice as VoIP across DSL Optical Access Using fiber in place of copper boosts data rates and extends reach many times over. Fiber may be deployed in point-to-point connections from a central access switch or an optical line termination to the subscriber s premises or to a subtended DSLAM. Also, several subscribers may share fiber in passive optical networks. Figure 7 shows these options, and the following sections outline them. Nokia Siemens Networks offers an extensive line of DSLAMs featuring a full range of DSL and Ethernet subscriber interfaces. Deeply committed to driving the development of tomorrow s VDSL2 technology, Nokia Siemens Networks leverages best-in-class performance and features ensuring outstanding quality of service to provide the best alternative available today for broadband access over copper lines. Ethernet network termination Single family optical network termination Multi dwelling optical network termination Passive optical splitters Optical line termination Subtended DSLAM Multi dwelling optical network terminations Figure 7: Optical access solutions

15 15/22 Broadband Access for all A brief technology guide PON technologies BPON GEPON GPON NG-PON DS bit rate 622 Mbps 1.2 Gbps 2.5 Gbps 10 Gbps US bit rate 155 Mbps 1.2 Gbps 1.2 Gbps 2.5 Gbps Splitting factor 32 Min 16 Max 64 Max 512 Payload ATM cells Ethernet ATM / Ethernet / TDM ATM / Ethernet / TDM 3 rd wavelength for Standardized Non-standardized Standardized Standardized cable TV overlay Passive Optical Networks (PON) Passive optical networks exploit fiber s ability to deliver highest data rates to subscribers. What makes PONs so attractive is that they use passive optical components that may be buried in cable ducts and need no dedicated power supplies. PON systems allow operators to share a single fiber access line among a cluster of buildings, using passive splitters to distribute traffic to individual homes as shown on the right of Figure 7. Able to cover up to 20 km between a central office and subscribers, today s PONs outreach DSL many times over, at the cost of investing in fiber architecture. PONs comprise optical line terminals (OLT) deployed at the central office and optical network terminals (ONT) at the customer premises. Designed for residential and business applications, ONTs offer a wide range of subscriber interfaces. PON systems vary in performance and supported bearer protocols (ATM, Ethernet, and TDM). Table 2 summarizes the various flavors of PON technology.

16 16/22 Broadband Access for all A brief technology guide Based on ATM transmission and widely used in North America, BPON (Broadband PON) supports 622 Mbps downstream and 155 Mbps upstream. The First Mile project (IEEE (2005) specifies GEPON (Gigabit Ethernet PON) as a technology for delivering Ethernet connectivity to the home. It transmits variablelength Ethernet frames to do this, and it is remarkably cost-effective because it uses widespread Ethernet technology. A new solution on the optical access market, GPON (Gigabitcapable PON) offers bit rates ranging up to unprecedented 2.5 Gbps downstream and 1.2 Gbps upstream. GPON outperforms existing PON technologies with the lowest overhead of just seven percent. With Ethernet (10/100/ 1000BASE-T), ADSL2plus/VDSL2, E1 leased lines, and POTS, it also offers the greatest flexibility in service and subscriber interfaces. Various network termination units single family and single business as well as highly flexible and scalable multi-dwelling units support these services. NG-PON (Next Generation PON) is a GPON enhancement. Nokia Siemens Networks is currently exploring its merits. NG-PON spans 100 km between the OLT and up to 512 ONTs, which means far fewer central offices and far less costs for carriers. With 10 Gbps downstream and 2.5 Gbps upstream, it is able to serve many more subscribers, and deliver higher rates to each subscriber. With GPON and GEPON, Nokia Siemens Networks today offers future-proof, high-bandwidth access solutions. GEPON capitalizes on Ethernet technology s economies of scale, and GPON solutions offer the highest efficiency and greatest flexibility.

17 17/22 Broadband Access for all A brief technology guide Point-to-point Ethernet Access Widespread and state-of-the-art, Ethernet (IEEE 802.3) offers standardized interfaces, off-theshelf components, and high market penetration, which adds up to costefficient networks. As Figure 7 shows on the left, point-to-point Ethernet access may serve as a highbandwidth pipe to a single subscriber or to connect a remote access node such as a subtended DSLAM. Nokia Siemens Networks offers point-to-point Ethernet access from its optical line terminations, which also serve passive optical networks. Operators may choose between line cards with multiple Gigabit Ethernet ports for point-to-point fiber access or those for passive optical networks. Both options deploy from the same box, so operators need not install added equipment, yet still retain total flexibility. Just one box leaves a smaller footprint and cuts operating expenditure Multi-Service Access Node (MSAN) Carriers are looking to triple play services and PSTN substitution to prevail in a fiercely competitive market. To capitalize on both, they must be able to flexibly stage greenfield deployments and extend legacy access networks. New subscriber interfaces, reliability, and QoS are essential for enabling PSTN functionality in the packet access network. A solution featuring a multi-service access node (MSAN) can rise to all these challenges. To do this, the MSAN must comprise an extensive range of subscriber interfaces such as DSL, Gigabit Ethernet (GE), legacy POTS/ISDN, and GPON, and several 10GE network interfaces. Flexibility also means freedom of choice will it be copper or active or passive fiber at the subscriber s end? The answer depends on the deployment scenario, be it the classic central office, FTTC, FTTB, or FTTH. Nokia Siemens Networks MSAN supports them all. It scales to suit demand, supports POTS interfaces with conversion to H.248 or SIP, and features state-of-the-art DSL, GE, and GPON interfaces. A future-proof MSAN solution must encompass easy migration to an H.248 or SIP-based NGN, yet support legacy POTS/ISDN interfaces to subscribers. This enables carriers to transition networks to NGN without disrupting service to POTS/ISDN phone customers. A comprehensive MSAN solution such as this helps keep customers, provide new services, win new customers, drive revenue, migrate the network to NGN, and transition it to IP/Ethernet. What s more, PSTN substitution can slash operational cost TV Cable TV cable technology plays a prominent role in the North American market. Cable operators in some European countries have begun seriously competing with incumbent carriers by delivering triple play services across cable with native TV built in. On the downside, up to 2,000 subscribers share the cable in a neighborhood. This entails lower data rates for each subscriber and a potential security risk because of weak encryption.

18 18/22 Broadband Access for all A brief technology guide Metro Aggregation A few IP routers at the edge of the backbone network can serve many access nodes and cover a large geographic area. While connecting edge routers and access nodes is easily done with an Ethernet aggregation network, ensuring QoS is not quite so easy. Many technologies can serve to set up dedicated tunnels in an Ethernet network, which is intrinsically connectionless. These include virtual LANs (VLANs, Carrier Ethernet technology), added labels to frames (Layer 2-MPLS technology), and VLANs with MAC addresses (PBB- TE technology, with standardization commencing in IEEE 802.1). QoS parameters such as bandwidth, delay, and the like may be assigned to traffic in these tunnels. Nokia Siemens Networks supports VLANs, Layer 2-MPLS, and PBB-TE on demand. Figure 8 shows applications for tunnels running through the packet switched Ethernet network. VLANs, Layer 2-MPLS, and PBB-TE serve to build these tunnels. Residential VLANs VoIP IPTV Tunnel Tunnel Tunnel PSTN TV/Video Server WWW Tunnel Business WWW VoIP WWW Tunnel VLAN#1 VLAN#2 Tunnel VLAN#N Business VLAN#1 VLAN#2 Tunnel Packet Network Tunnel VLAN#1 VLAN#2 Business VLAN#N VLAN#N Mobile Backhaul Mobile Backhaul Node B VLANs User Control Tunnel Tunnel User Control RNC O&M O&M Figure 8: Aggregation network tunnels for QoS assurance Network nodes must be tremendously flexible and scalable to meet the demands of applications such as wholesale business environments. To achieve both ends, Nokia Siemens Networks develops customerspecific traffic engineering solutions for its feature-rich product families.

19 19/22 Broadband Access for all A brief technology guide 3.3 Broadband Access and Fixed Mobile Convergence (FMC) Broadband user access provides the underpinning for delivering all manner of user services regardless of the means of access. VoIP is a typical example of a broadband access-enabled user service. Fixed broadband access availability has prompted a major shift in the way voice services are provided. From a network perspective, broadband access is the key enabler for the transition from vertical to horizontal networks. Traditional networks were vertical in the sense that carriers deployed dedicated combinations of access, aggregation, and core networks for voice and data as well as for mobile and fixed networks. take advantage of the benefits of home wireline connections and the wide availability of 3G radio in mobile terminals. All promise to bring high data rates to end-users 3G terminals at home without burdening the outdoor 3G network. 4. Choosing Your Broadband Strategy Broadband-enabled networks use IP bit pipes with enough bandwidth to deliver all kinds of services to the end-user. Now metro aggregation and backbone networks are migrating towards pure packet networks, and service control core networks towards unified IP service control. The service control and application layers are access-independent. A horizontal layered network is emerging. The IP Multimedia Subsystem (IMS) enables unified IP service control, as well as fixed-mobile convergence (FMC) towards next-generation converged networks. From an end-user perspective, convergence centers on user devices and services that is, any service on any device, in a way best fitting the device s capabilities. WLAN-enabled mobile phones can be used for VoIP over WLAN with UMA (Unlicensed Mobile Access) and Voice Call Continuity (VCC) based on IMS. Desktop computers and notebooks have been the primary broadband access devices in homes, but with adequate indoor coverage available, wireless personal broadband devices will see increasing use. Femto home base stations also Economic conditions differ markedly across the globe, so one must examine individual markets to fully understand the telecom industry s situation worldwide. Regulation continues to play a key role, as wireless spectrum is a regulated asset. Wireline connections to homes are under regulatory scrutiny because more than one line entering a building is rarely feasible. Many emerging markets lack competition because of regulatory barriers. In markets where few providers do business or monopolies still prevail, services are expensive for customers and consumers. Often there is much room for improvement in bandwidth, quality of service, and delivery costs. Re-regulation enabling fair competition is likely to extend the scope and cut the cost of services as more players go to market with various alternative (wireline and wireless) technologies. This would foster investments in access, aggregation, and transport networks, which boosts bandwidth availability and affords customers and consumers better quality at lower prices. And as network and service providers operate more efficiently, their profit margins grow. Beyond that, more available, more affordable services can bring socio-economic benefits to customers and consumers.

20 20/22 Broadband Access for all A brief technology guide 4.1 Business Environment and Network Operator Models Access network operators may be classed in three general categories based on the type of access they provide mobile, wireline, and hybrid operators. Another distinction can be made between incumbents and new entrants based on their company history and business situation. Challengers may ponder entering the business of providing access for many. ISPs (Internet service providers) may seek to leverage their brand and offer a full solution including access and services. Broadcasters may also wish to offer communication services. One way for a challenger to become a network operator is to start off as a virtual network operator (VNO) and gradually invest in an infrastructure, or disrupt service and invest heavily in deploying a new access technology to reach end-users. By choosing to don the mantle of integrated communications providers, operators can create what industry pundits have dubbed quadruple play services sticky bundles of wireline voice, broadband data, TV services, and mobile access. With easy-to-use services, one-on-one customer relations, a single bill, and a strong lock-in, the benefits are certainly persuasive. The wireline backbone and international connections in many emerging markets merit improvement. A mobile operator may not be able to lease transmission lines, or there may be no Internet backbone for an operator (wireline or wireless) to connect to. Although a situation such as this may well be an opportunity for securing a strong foothold in both wireline and wireless domains, it may also entail spreading investments over a very wide range of technology. 4.2 The Best Technology for You Estimates put the world s installed copper base at one billion households, serving some two billion people. That is not enough. Nokia Siemens Networks envisages five billion users connected to the Internet by It will take extensive use of wireless access as well as new wireline installations to reach that number. User data rate [Mbps] 1, ADSL 1-3 Mbps Wireline ADSL 6-8 Mbps ADSL2plus Mbps UMTS* Mbps GPON* VDSL2 100 Mbps Mbps HSDPA* 1.8 Mbps NG-PON* DSM L3 WiMAX* HSPA MIMO* HSDPA* Mbps Wireless LTE* 0.01 GPRS* Mbps * Bandwidth of shared media (e.g. wireless, PON) are commercial offers per subscribers Year of user availability Figure 9: The development of real-world wireline and wireless user data rates

21 21/22 Broadband Access for all A brief technology guide Again, wireline can offer clearly higher data rates than wireless solutions. Figure 9 tracks the bit rate evolution. The wireline user data rate is some 30 times that of wireless, with both on a similar evolutionary trajectory. Wireless data rates have attained a level enabling satisfying performance for most services, with the notable exception of IP TV and its big appetite for high data rates. Incumbent wireline operators leverage legacy copper assets to offer broadband services with DSL. In view of constantly growing end-user bandwidth demand, fiber must be brought closer to the subscriber. FTTC and FTTB are the fiber deployments of choice. The next step up is FTTH, where fiber runs right to the subscriber s home. Bandwidth-hungry applications like high-definition TV and corporate connectivity will drive the demand for wireline network deployments. Carriers wishing to provide high-speed wireline connections beyond 8 Mbps to suburban and especially rural areas across copper lines face the formidable challenge of loop length constraints. High bit rate offerings feasibility hinges on how close the fiber connection is to the home and how much it costs to put fiber in the ground. Of course, any scenario mandating mobility or nomadic use entails wireless technology, but if a region lacks wireline infrastructure, wireless can also provide broadband coverage at far lower cost than new wireline installations. This makes wireless broadband access an appealing option for densely populated urban and sparsely populated rural areas, especially in emerging markets. What s more, prices for wireless handsets are eroding fast, and consumer pricing strategies can be geared to align demand and available capacity. Wireless broadband data requires high-capacity transport to the base station, which microwave radio is equipped to provide. Aggregate connections may demand higher capacity with fiber connections. And having fiber connections available for transport to at least some of the base station sites will be the true enabler for mass market wireless broadband data. To choose the wireless technology that suits their purposes best, operators must analyze assets such as their wireline network, frequency licenses, legacy equipment and sites, the underlying network and compatibility requirements, and the services they wish to deliver. There are a number of different broadband access technologies available today. Nokia Siemens Networks has the widest range of broadband access solutions in the industry. Nokia Siemens Networks can help the operators to select the best solution for them with respect to CAPEX, OPEX, roll-out speed and support for their planned services. Unique in the market, Nokia Siemens Networks comprehensive solution portfolio and long experience in wireline and wireless broadband access covers different operator needs on a broad front. We provide standardized, complementing, and integrated broadband access network solutions that deliver the necessary data rates at best cost per bit ratio.

22 5. Abbreviations ADSL Asymmetric DSL ATM Asynchronous Transfer Mode BRAS Broadband Remote Access Server BSS Base Station Subsystem BTS Base Transceiver Station CAT5/6/7 Category class 5/6/7 of twisted-pair copper cables for data transfer CAPEX Capital Expenditure CATV Cable TV CET Carrier Ethernet Transport CLEC Competitive Local Exchange Carrier CPE Customer Premises Equipment DSL Digital Subscriber Line DSLAM Digital Subscriber Line Access Multiplexer DSM L3 Dynamic Spectrum Management Level 3 EDGE Enhanced Data Rates for GSM Evolution EV-DO Evolution data only (of cdma2000) FDD Frequency Division Duplex FMC Fixed Mobile Convergence FTTB Fiber To The Building FTTC Fiber To The Curb FTTH Fiber To The Home GE Gigabit Ethernet GSM Global System for Mobile communication HSDPA High-Speed Downlink Packet Access HSPA High-Speed Packet Access (= HSDPA + HSUPA) HSUPA High-Speed Uplink Packet Access IEEE Institute of Electrical and Electronics Engineers I-HSPA Internet HSPA IMS IP Multimedia Subsystem IMT International Mobile Telephony IP Internet Protocol ISDN Integrated Services Digital Network