In the broadband supply chain, local access
networks are those that directly connect end users to broadband services, the so-called
“last mile.” Several wireline and wireless broadband technologies are used today
to support local access networks. Having multiple broadband access options in a
country increases consumer choice, stimulates intermodal competition, enhances quality
and innovation, and is generally associated with lower retail prices. However, countries
may not be able to use all possible technological choices for historical, technical,
regulatory, or financial reasons. As governments seek ways to promote broadband
development, they will need to recognize the strengths and limitations of their
existing level of infrastructure development—both for its upgrade possibilities
as well as for developing appropriate incentive and competition policies.
5.7.1 Wireline Access Technologies
This section examines wireline broadband
access technologies, including digital subscriber line (DSL), cable modem, fiber
to the premises (FTTP), and other options. The first three account for almost all
wireline local access technologies worldwide (Figure 5.8).
220.127.116.11 Digital Subscriber Line
The public switched telephone network (PSTN)
line running to the subscriber’s premise has traditionally been copper wire, with
a bandwidth of 3 to 4 kilohertz (kHz). This narrowband channel offers an analog
carrier originally configured to provide a single telephone call. Two “twisted-pair”
copper wires are used to support duplex communications (that is, the ability to
send and receive at the same time). The PSTN has also supported the capability for
narrowband Internet access, with subscribers using a modem to dial up an ISP.
DSL technologies use
special conditioning techniques to enable broadband Internet access over that same
PSTN copper wire. Transmission speeds vary as a function of the subscriber’s distance
from the telephone company switching facilities, the DSL version, the extent of
fiber in the network, and other factors. DSL requires that the bandwidth over the
copper line be separated between voice and data. A quartz crystal splitter is used
to filter the data channel when using the shared copper local loop for telephone
service. Similarly the voice channel must be filtered when the line is used for
broadband Internet access. Nonetheless, users can continue to make and receive PSTN
telephone calls when using DSL data services. As is the case with dial-up access
to the Internet, subscribers must have a modem installed between their computer
and the copper wire. A DSL modem modulates upstream signals to the Internet and
demodulates downstream traffic to the subscriber.
Figure 5.8 Number of Broadband Subscribers Worldwide,
2007–09, by Type of Wireline Technology
In addition to retrofitting
their copper lines, telephone companies also have to upgrade their switching facilities
in order split traffic into voice and data streams and to route data traffic between
subscribers and the Internet. Traffic exchanged with the Internet is routed through
a digital subscriber line access multiplexer (DSLAM). This device aggregates (multiplexes)
upstream traffic from DSL subscribers onto high-speed trunk lines to be delivered
to the Internet. Similarly, the DSLAM disaggregates (demultiplexes) traffic arriving
from the Internet and routes it to the intended subscriber.
DSL has gone through
several evolutions supporting increasing speeds and distances (Table 5.2). The technology
is standardized within the International Telecommunication Union (ITU) under Study
Group 15 and the G series of ITU-T recommendations.* An asymmetric digital subscriber
line (ADSL) maintains the frequency bandwidth of voice (that is, below 4 kHz) for
telephony service. Broadband is transmitted on two other frequency bands; one is
allocated to a low-speed upstream channel (25 to 138 kHz), and the other is allocated
to a high-speed downstream channel (139 kHz to 1.1 MHz). The theoretical maximum
downstream bit rate of 6 Mbit/s and maximum upstream rate of 640 kbit/s are defined
by the standard.
Table 5.2 DSL Connection Speeds, by Type of Line
Source: Adapted from ITU 2008.
Note: The speeds shown are those specified
in the standard, not necessarily those experienced by end users.
Type of line
Asymmetric DSL (ADSL)
Very high-speed DSL (VDSL)
In the ADSL2 standard,
more efficient modulation and coding are implemented to improve the bit rate, quality,
and, to a lesser degree, coverage. The standard defines maximum bit rates of about
8 Mbit/s downstream and 800 kbit/s upstream. The data rate is increased with ADSL2+
through doubling the frequency bandwidth by including the frequency band between
1.1 and 2.2 MHz. This results in a standard of 16 Mbit/s downstream and 800 kbit/s
Very high-speed digital
subscriber line (VDSL) allows for much greater symmetrical data rates accomplished
by using improved modulation techniques and adding more frequency bandwidth to the
copper wire. However, the distances from the switch to the end user must be short
or fiber must be installed to the curb. The VDSL2 standard overcomes some of these
challenges by extending distances and reducing interference, while increasing bit
rates up to 100 Mbit/s for distances less than 300 meters.
In Israel incumbent operator
Bezeq has been rolling out VDSL2 as part of its NGN deployment, with coverage to
around half the households by the end of 2010 (Bezeq Group 2011). It was advertising
bandwidth of 100 Mbit/s for DSL connections on its website in March 2011. Bezeq
plans to offer up to 200 Mbit/s through VDSL bonding, which uses two copper pairs
While DSL technology
has evolved with ever-increasing data rates and remains the most popular wireline
broadband technology in terms of subscriptions, its biggest constraint is bandwidth
deterioration as the distance from the exchange increases, as shown in Figure 5.9.
Figure 5.9 Speed of DSL and Distance
Note: Theoretical maximum speed at 2 kilometers
is about 14 Mbit/s.
18.104.22.168 Cable Modem
Cable modems provide subscribers with access
to broadband services over cable television (CATV) networks. CableLabs developed
standards for cable modem technology in the late 1990s.* The technical guidelines
are called Data over Cable Service Interface Specification (DOCSIS). The DOCSIS
guidelines have been progressively enhanced in terms of functionality (for example,
support for IPv6) and speed (Figure 5.10). The latest version is 3.0, with a slightly
different European implementation (EuroDOCSIS). DOCSIS has been approved as an ITU
Figure 5.10 Cable Modem Connection Speeds, by Specification :
unit indicator = Mbit/
Source: Adapted from Motorola, “Planning an
Effective Migration to DOCSIS® 3.0,” www.motorola.com/staticfiles/Video-Solutions/ultrabroadbandsolutions/pdf/Migration_to_DOCSIS30.pdf.
The first DOCSIS specification
was version 1.0, issued in March 1997, which uses the subscriber’s copper wire telephone
line for upstream traffic. Beginning in April 1999 with the DOCSIS 1.1 revision,
cable operators added quality of service capabilities and began installing fiber
optic cables originating at the cable operator’s switching facility (that is, the
head end) and terminating at a junction box near the subscriber. This combination
of coaxial cable and fiber optic is referred to as a hybrid fiber coaxial (HFC)
network. Due to increased demand for symmetric services such as IP telephony, DOCSIS
2.0 was released in December 2001 to enhance upstream transmission speeds. Most
recently, the specification was revised to increase transmission speeds significantly
(DOCSIS 3 and EuroDOCSIS 3).
Older CATV networks cannot
sustain higher bandwidths without significant upgrades. CATV operators that have
recently built out their networks generally have a high-capacity bandwidth network
from which they can partition a portion for broadband data service. Internet access
via CATV networks uses a modem, and broadband access is typically called cable modem
service. Television content is separated from Internet traffic at the head end.
A cable modem termination system (CMTS) exchanges digital signals with cable modems
and converts upstream traffic into digital packets that are routed to the Internet.
The CMTS receives traffic from the Internet and routes it to the appropriate cable
modem of the subscriber. Because CATV networks use a cascade of amplifiers to deliver
video programming, cable modem service has fewer limitations than DSL with regard
to how far subscribers can be located from the head end.
frequency has enabled bandwidth increases for cable modem broadband. For example,
adding a 6 MHz channel for Internet access provides download speeds typically between
1.5 and 15 Mbit/s and upload speeds of 384 kbit/s to 3 Mbit/s. Channel bonding adds
an additional 6 MHz channel to increase speed. However, unlike DSL where subscribers
are provided a dedicated connection between their home and the provider’s switch,
cable modem broadband capacity is shared among nearby users, which can cause a marked
deterioration in service at peak times.
Until recently, the world’s
fastest cable broadband network was in Japan, where J:Com offers speeds of 160 Mbit/s
based on DOCSIS 3 (Hansell 2009). It achieved this rate through a US$20 per subscriber
upgrade, considerably cheaper than building out a new fiber to the home (FTTH) network.
In 2011, however, several companies began rolling out EuroDOCSIS services at speeds
up to 200 Mbit/s (Nastic 2011).
Although some countries
have a significant number of CATV subscribers, cable broadband penetration on a
worldwide basis remains relatively low, particularly in developing countries. A
main reason is that cable operators have not made the necessary investment in HFC
networks. Another factor is that regulatory restrictions in some countries forbid
cable operators from providing Internet or voice services. In many countries, however,
cable has never achieved significant market penetration, and satellite TV or digital
terrestrial TV offers a substitute for multichannel television distribution.
22.214.171.124 Fiber to the Premises
Fiber to the premises refers to a complete
fiber path linking the operator’s switching equipment to a subscriber’s home (FTTH)
or business (FTTB). This distinguishes FTTP from fiber to the node (FTTN) and fiber
to the curb (FTTC), which bring fiber optic cable part of the way to a subscriber’s
premises (Figure 5.11). FTTN and FTTC are therefore not subscriber access technologies
like FTTP, but are used to extend the capabilities of DSL and cable modem networks
by expanding fiber optic cable deeper into the network. Again, the exact technology
a company or government chooses to deploy or promote will depend on the unique circumstances
in each country. FTTP offers the highest speeds of any commercialized broadband
technology. However, it is not widely available around the world, with the FTTH
Council reporting that only 26 economies had at least 1 percent of their households
Figure 5.11 Diagram of Various FTTx Systems
Source: Wikipedia, http://upload.wikimedia.org/wikipedia/commons/3/32/FTTX.png.
Note: The building on the left represents
the central office; the building on the right represents one of the buildings served
by the central office. The dotted rectangles represent separate living or office
spaces within the same building.
FTTP sometimes replaces
existing copper wire or coaxial cable connections but is also increasingly popular
for greenfield building projects (where a new housing or commercial development
is being built and no telecommunications infrastructure presently exists). FTTP
can be designed with various topologies: point-to-point, where the optical fiber
link is dedicated to traffic from a single subscriber; point-to-multipoint, where
fiber optic cables branch to more than one premise and thus share traffic; and a
ring, where the fiber optic cable is designed in a closed loop that connects various
premises. The information flowing over the fiber optic cable is guided by protocols
that have been standardized by the IEEE or the ITU (Table 5.3).
Most FTTP implementations
are based on passive optical network using point-to-multipoint topology serving
multiple premises with unpowered optical splitters. Traffic is handled using an
optical line terminal at the service provider’s central office and optical network
terminals, also called optical network units, at the subscriber’s premises.
Although speeds on FTTP
networks can be symmetrical and offer up to 1 Gbit/s, many service providers provide
substantially lower asymmetrical speeds (often because the national backbone cannot
handle high speeds). City Telecom, a broadband operator in Hong Kong SAR, China,
for example, has over half a million homes connected to a fiber network. It offers
1 Gbit/s fiber service for about US$25 per month.*
Table 5.3 FTTP Access Protocols
Source: Fiber to the Home Council, “Definition
of Terms,” January 9, 2009, www.ftthcouncil.eu/documents/studies/FTTH-Definitions-Revision_January_2009.pdf.
Ethernet in the first mile
Ethernet over point-to-point
Ethernet passive optical network
Broadband passive optical network
Gigabit passive optical network
126.96.36.199 Other Wireline Broadband
Although DSL, cable modem, and FTTP account
for nearly all subscriptions worldwide, other technologies include Ethernet-based
local area networks (LANs) and broadband over powerline (BPL). Wireline LANs are
used to connect many subscribers in a large building such as apartments or offices.
Subscribers are typically connected directly to a fiber or Ethernet backbone where
broadband access is distributed through the LAN. Some countries report LAN subscriptions
as a separate wireline broadband access category. LANs can be wireline (using coaxial
cable or twisted pair [Cat3 or 10Base-T]) or wireless, based on the IEEE 802.3 or
802.11 standards. They are typically used within a home or a public access facility.
BPL uses the electricity
distribution network to provide high-speed Internet access. BPL operates by differentiating
data traffic from the flow of electricity. This separation occurs by using a much
higher frequency to carry data through the copper wires, coupled with encoding techniques
that subdivide data traffic into many low-power signals or that spread the bitstream
over a wide bandwidth. The former encoding scheme is known as Orthogonal Frequency
Division Multiplexing (OFDM), and the latter is a type of spread spectrum technology.
In both technologies, digital signal processing integrated circuits help to keep
data traffic intact, identifiable, and manageable.
BPL has so far failed
to achieve wide-scale commercial success, partly because of interference issues
and partly because of uncertainty over whether and how data transmission can take
place at significant volumes over an entire electricity distribution grid. The problem
stems from when transformers are used to reduce the voltage of electricity to that
used by residential and business users. Because a BPL distribution grid requires
repeaters that amplify data signals, such networks can be costly to build. In addition,
BPL reportedly can interfere with some radio transmissions, and there is no international
standard for BPL. Finally, a big barrier in many low-income nations is the lack
of a reliable electrical grid to carry the data signals.
A building’s internal
electrical wiring can also be used as a type of LAN. Devices with Ethernet ports
can be interconnected using plug-in adapters over electrical wiring to create home
and office networks. The HomePlug Powerline Alliance has created an adapter standard
and reports that it had sold over 45 million such devices by March 2010, accounting
for 75 percent of the market.*
The ITU covers the use of electrical wiring for home networking in its G.hn Recommendation.*
5.7.2 Wireless Access Technologies
The immense success of cellular telephone
service attests to the attractiveness of wireless technologies as a local access
solution. Factors in their success include being generally easier and cheaper to
deploy than wireline solutions and consumers’ fondness for mobility. Technological
innovations offer the near-term opportunity for widespread mobile access to the
Internet, as next-generation wireless networks have the technological capability
to offer bit rates at near parity with current wired options, though not yet at
the same price points. The ability of carriers to offer such services will depend
on whether sufficient radio spectrum can be allocated for mobile broadband services
and whether innovations in spectrum conservation techniques can help operators to
meet consumer demand.
188.8.131.52 Early Wireless Broadband Standards
Although an International Mobile Telecommunications-2000
(IMT-2000) standard, EDGE initially offered less than broadband speeds (120 kbit/s,
according to the GSMA).*
A newer version of EDGE (Evolution) can achieve top speeds of up to 1 Mbit/s, with
average throughput of around 400 kbit/s (Ericsson 2007), but EDGE is not considered
a true mobile broadband solution. It can be attractive since it provides an upgrade
path for global system for mobile (GSM) communications networks, allowing higher
speeds than GPRS,*
particularly where investment is constrained, regulators have not released mobile
broadband spectrum, or gaps in coverage need to be filled.
CDMA2000 refers to the CDMA2000 1x and CDMA2000
Evolution Data Optimized (EV-DO) technologies that are part of the IMT-2000 standards.
CDMA2000 builds on second-generation (2G) CDMA technologies, known as ANSI-95 or
cdmaOne, and uses a 1.25 MHz channel size. CDMA2000 attractions include backward
compatibility with earlier standards, use for either wireline or mobile wireless,
and spectrum flexibility due to small channel size and availability in a range of
frequencies including 450 MHz, the only IMT-2000 standard commercially available
in that band (Figure 5.12; CDMA Development Group 2000).
Figure 5.12 Frequency Bands Used by CDMA2000
Table 5.4 EV-DO Peak and Average Speeds
Source: CDMA Development Group, www.cdg.org/technology/cdma2000/spectrum.asp.
a. Identified at the 2007 World Radiocommunication
b. Includes 698–862 MHz band in region 2 (Americas),
790–862 MHz band in region 1 (Europe, Middle East, Africa, the Russian Federation,
and the Commonwealth of Independent States), and 790–960 MHz identified for IMT
in region 3 (Asia-Pacific).
c. Future availability.
Source: CDMA Development Group 2011.
Number of countries
CDMA2000 1X supports
circuit-switched voice up to and beyond 35 simultaneous calls per sector and high-speed
data of up to 153 kbit/s in both directions. Although it was the first IMT-2000
technology to be commercially adopted, it is not considered mobile broadband due
to the low speed. However, CDMA2000 1xEV-DO uses packet-switched transmission specifically
designed and optimized for mobile broadband networks. There have been three revisions
to the EV-DO standard (Rel. 0, Rev. A, and Rev. b), each offering higher speeds
than its predecessor (Table 5.4). In September 2010 there were 66 countries with
Rel. 0 networks, 57 countries with Rev. A networks, and three countries with Rev.
B networks, together serving 156 million subscribers around the world.* One of the fastest EV-DO
networks is in Indonesia, where operator Smart Telecom is using Rev. B to achieve
an average download speed of 8.6 Mbit/s and a peak download speed of 9.3 Mbit/s.*
Box 5.2 describes the experience of Mexico and Sweden with CDMA 450 MHz.
Box 5.2 CDMA 450 MHz for High-Speed Rural Internet Access
Sources: CDMA Development Group 2009, 2011; Swedish Post and Telecom
Agency 2011; Swedish Post and Telecom Agency, “Broadband Survey, PTS Statistics
Portal,” www.statistik.pts.se/broadband; Net1, “Teknik,” www.net1.se/omnet1/teknik.aspx;
Net 1, “Mobilt Bredband,” www.net1.se/privat/bredband.aspx.
Swedish kroner converted to U.S. dollars using 2010 annual average exchange rate.
One of the attractions of 450 MHz spectrum
is its use for rural communications. Because of the lower frequency range, coverage
is wider, and fewer base stations are required so that investment costs are significantly
lowered. CDMA2000 1X and EV-DO operate in 450 MHz, and their use is helping to extend
high-speed connectivity to rural areas. Although the number of subscriptions may
not be high, they are often the only high-speed networks available in small rural
communities, where they can have an important socioeconomic impact.
In Mexico the incumbent
Telmex won the government’s Fund for Telecommunications Social Coverage with its
bid to provide services in some 8,500 rural communities with around 7 million low-income
inhabitants. It is using CDMA450 where each base station covers more than 80 kilometers,
providing 150 kbit/s Internet connections. In addition to regular post- and prepaid
subscriptions (around 180,000 by late 2009), Telmex also set up some 500 “digital
agencies,” which offer personal computers, printers, and Internet access to the
In Sweden CDMA2000 1xEV-DO
in the 450 MHz band is attributed with reducing by half the number of people with
no access to broadband between 2009 and 2010. Over 99 percent of Swedes living in
sparsely populated regions have access to the CDMA 450 MHz network. Service is provided
by Net 1, which has built a nationwide CDMA network in the 450 MHz frequency band,
providing up to 25 times more coverage per transmitter than Universal Mobile Telecommunications
System (UMTS) networks using the 900 MHz, 1,800 MHz, and 2,100 MHz bands. As a result,
the 450 MHz network is available in places where it is not economically viable for
competitors to provide coverage. Net 1 is using EV-DO Rev. A, offering download
speeds of 3.1 Mbit/s for SKr 229 (US$32) per month.
According to the CDMA
Development Group, CDMA450 can be profitable at average revenue per user of less
than US$8 per month, and handsets are available for less than US$25.
The first two generations of mobile networks
were characterized by analog and then digital technology. There were no global standards,
and a variety of technologies evolved. In an effort to standardize third-generation
(3G) mobile systems expected to be commercialized around the year 2000, the ITU
developed the International Mobile Telecommunications (IMT) family of standards.
Despite the goal of standardization, five significantly different radio interfaces
for IMT-2000 were approved in ITU-R Recommendation M.1457 in 1999. WiMAX was added
to M.1457 in 2007 (Table 5.5).*
Table 5.5 IMT-2000 Radio Interfaces
Source: ITU, Radio Communication Sector, Recommendation
Radio interface technology
CDMA direct spread
Original frequencies in standard: 1,920–1,980
MHz as uplink and 2,110–2,170 MHz as downlink
Later added: 2.6 GHz, 1,900 MHz, 1,800 MHz,
1,700 MHz, 1,500 MHz, 900 MHz, 850 MHz, and 800 MHz bands as well as a pairing of
parts, or whole, of 1,710–1,770 MHz as uplink with whole, or parts, of 2,110–2,170
MHz as downlink
Including 1X and EV-DO. As the 3G-evolution path for 2G TIA/EIA-95-B standards,
assumption is that 3G would use the same 2G frequencies
Original frequencies in standard: 1,900–1,920 MHz and 2,010–2,025 MHz for both uplink
and downlink operation. Added later: 1,850–1,910 MHz, 1,910–1,930 MHz, and 1,930–1,990
Provides an evolution path for GSM/GPRS so assumption is that implementation would
use the same 2G frequencies
Not widely used as a mobile cellular technology
OFDMA TDD WMAN
WiMAX (IEEE 802.16)
Frequencies not mentioned in standard. Generally commercially implemented in the
2.3, 2.5/2.6, and 3.5 GHz bands
Wideband CDMA (W-CDMA), also referred to
as UMTS, is characterized by the use of Frequency Division Duplexing (FDD). It uses
paired spectrum in 5 MHz wide radio channels. W-CDMA is often marketed as an upgrade
from GSM, although it requires new base stations and initially new frequency allocation.
However, since W-CDMA handsets are generally dual-mode to support GSM, roaming between
the two networks is typically seamless. Given its ties to the dominant GSM standard,
W-CDMA has been the most successful of the IMT-2000 technologies in terms of subscriptions.
High-Speed Packet Access
refers to the various software upgrades to achieve higher speeds on W-CDMA networks
Initial speed improvements are listed below, although some operators have been able
to achieve even higher data rates through various enhancements:
High-Speed Downlink Packet Access (HSDPA) increases download data rates. Speeds
achieved top 14.4 Mbit/s, with most operators offering speeds up to 3.6 Mbit/s.
Upload speeds are 384 kbit/s.
High-Speed Uplink Packet Access (HSUPA) increases upload rates. Upload speeds are
increased to a maximum of 5.7 Mbit/s.
HSPA+ (also known as HSPA Evolved) offers significant speed improvements. HSPA+
enables speeds up to 42 Mbit/s in the downlink and 11 Mbit/s in the uplink. In March
2011 there were 128 HSPA+ networks in 65 countries, including 95 HSPA+ networks
offering peak rates of 21 Mbit/s, 11 offering peak rates of 28 Mbit/s, and 22 offering
peak rates of 42 Mbit/s.*
Table 5.6 W-CDMA and HSPA Theoretical Data Rates
Source: GSMA, “About Mobile Broadband,” www.gsmamobilebroadband.com/about/.
Specification for upload and not download
Some of the key characteristics of Time
Division–Synchronous Code Division Multiple Access (TD-SCDMA) are that it uses Time
Division Duplexing (TDD), unlike W-CDMA, which uses FDD, and does not require paired
spectrum, increasing spectrum flexibility. The word “synchronous” refers to the
fact that the base station synchronizes upstream signals. Interference is reduced
and capacity is increased; however, there is reduced coverage compared to other
technologies. China is the only country where TD-SCDMA has been deployed on a significant
scale (Box 5.3). Launched by China Mobile on January 7, 2009, the network covered
656 cities by the end of 2010, with 20,702,000 subscribers (China Mobile 2011).
Box 5.3 Three 3G Technologies in China
China is one of the few countries in the
world with three kinds of mobile broadband networks. In early January 2009 the Ministry
of Industry and Information Technology awarded 3G licenses to three different operators
in China for three different IMT-2000 technologies. China Mobile received permission
to use the homegrown TD-SCDMA technology, becoming the world’s first implementation
of this standard. China Unicom was approved to operate 3G using W-CDMA, which has
been widely deployed in many countries. Meanwhile, China Telecom was awarded a 3G
license using CDMA2000 technology. It already operated a CDMA2000 network, and the
new license allowed it to upgrade to faster EV-DO speeds. Competition between these
three technologies has rapidly boosted the take-up of 3G: from no subscribers in
2008 to 10 million in 2009 and to 47 million by the end of 2010. Although the networks
are incompatible for now, it is hoped that they will evolve to the next-generation
mobile standard, LTE.
WiMAX consists of several products based
on IEEE 802.16 standards for wireless broadband. Originally designed as a wireline
backbone technology, the mobile version of WiMAX (802.16e) is a more recent incarnation
that was approved by the ITU as an IMT-2000 standard in 2007.* Distinguishing features
of WiMAX include IP packet switching, the use of Scalable Orthogonal Frequency Division
Multiple Access (SOFDMA), unpaired spectrum using TDD, and operation in the 2.3,
2.5/2.6, and 3.5 GHz bands. Top theoretical speeds for wireless WiMAX are 46 Mbit/s
on the uplink and 7 Mbit/s on the downlink, roughly equivalent to HSPA+ networks
(Pinola and Pentikousis 2008).
Although mobile WiMAX
is standardized as an IMT-2000 technology by the ITU, it is often used as a fixed
wireless access technology (IEEE 802.16; Marks 2010). One of the early implementations
was the Korean variation called WiBro (WiMax Forum 2008). The government issued
spectrum in the 2.3/2.4 GHz band in 2005, and WiBro was commercially launched in
April 2007. By the end of 2010, WiMAX networks were used in 149 countries covering
more than 823 million people.*
The number of WiMAX subscribers around the world was estimated at 13 million in
December 2010 (Maravedis 2011).
The ITU has been working on standards for
the next generation of wireless systems for several years. In March 2008 it issued
a circular letter specifying the provisions for International Mobile Telecommunications-Advanced
(IMT-Advanced) networks, which are generally defined as systems “that go beyond
those of IMT-2000” (Blust 2008). One of the most significant requirements is peak
data rates of 100 Mbit/s for high mobility and 1 Gbit/s for low mobility. In
October 2010 the ITU announced that two technologies met the requirements for IMT-Advanced:
LTE-Advanced and WirelessMAN-Advanced (ITU 2010).
LTE and LTE Advanced
Development of the LTE mobile network standard
started in 2004. One goal was to achieve higher data speeds to support the rising
growth of Internet access over mobile phones. Targeted speeds were initially 100
Mbit/s for downloads and 50 Mbit/s for uploads. LTE uses OFDM for downloads and
Single Carrier-Frequency Division Multiple Access (SC-FDMA) for uploads. LTE is
designed for frequency flexibility, with bandwidth requirements ranging from 1.25
and 20 MHz and support for both paired (FDD) and unpaired (TDD) bands.
LTE standards have been
developed under the auspices of the 3G Partnership Project (3GPP). The 3GPP Release
8, issued in December 2008, forms the basis for initial LTE deployments. It has
theoretical maximum download speeds of 300 Mbit/s and upload speeds of 75 Mbit/s.
In order to meet global requirements for fourth-generation (4G) mobile networks,
3GPP developed LTE Release 10 and Beyond (LTE‐Advanced),
which was submitted to the ITU in October 2009.
Although LTE was developed
within the auspices of the 3GPP, whose work includes technical specifications for
GSM, W-CDMA, and HSPA technologies, there is no straightforward migration path.
So far, LTE deployments have required the purchase of new equipment by operators
and new devices by users.
The world’s first LTE
deployment was by TeliaSonera when it simultaneously launched networks in Stockholm,
Sweden, and Oslo, Norway, at the end of 2009 using the 2.6 GHz frequency band.*
Verizon’s LTE network launch in the United States in December 2010 is noteworthy
for using the 700 MHz frequency band.*
Verizon reported that speeds were 5–12 Mbit/s download and 2–5 Mbit/s upload. According
to 4G Americas, 19 commercial LTE networks were operating worldwide in 14 countries
in March 2011.
WirelessMAN-Advanced is standardized as
IEEE 802.16m and offers backward compatibility with IEEE 802.16e, an IMT-2000 technology.
It meets the IMT-Advanced data rate requirements with a theoretical 180 Mbit/s downlink
using a 20 MHz TDD channel (WiMax Forum 2010). Multiple channels can be aggregated
to support 1 Gbit/s speeds (Jiaxing and Guanghui 2010).
Wi-Fi refers to the IEEE 802.11 family of
standards specifying wireless local area networking over 2.4 and 5 GHz frequency
bands. Wi-Fi is not typically deployed as a commercial local access network; it
is used most often to redistribute a broadband connection to a wider group of users
in homes, offices, and “hotspots.” Wi-Fi technology has gone through several updates
that provide varying speeds depending on the frequency and version used (Table 5.7).
Table 5.7 Wi-Fi Speeds
Source: Wi-Fi Alliance, “Discover and Learn,”
Frequency band (GHz)
Maximum data rate (Mbit/s)
Reportedly one in 10
people around the world uses Wi-Fi.*
Its success is attributed to several factors, including embedding Wi-Fi chips in
portable computers and smartphones, the fact that it operates on a license-exempt
and the relative ease of installation compared to wired networks, with the majority
of the upgrade costs lying with the consumer rather than the operator.
In addition to sharing
broadband connectivity with devices in home and office networks, Wi-Fi is being
used for the following significant applications:
Subscription-based access to broadband. Many wireline ISPs around
the world offer Internet access through Wi-Fi hotspots at airports, coffee shops,
and other locations. This is seen as a complement to their traditional service.
Municipal Wi-Fi networks. Large-scale Wi-Fi networks have been deployed
in some urban areas around the world to provide free Internet access. Wireless@KL
in Kuala Lumpur, Malaysia, provides free 512 kbit/s access throughout the city;
faster speeds are enabled through payment.*
The Kuala Lumpur City Hall and the Malaysian Communications and Multimedia Commission
sponsor the KL Wireless Metropolitan project in collaboration with Packet One Networks,
an ISP. Some 1,500 hotspots have been deployed in the city.
Relief for congested mobile networks. Mobile operators were initially lukewarm
about handsets with Wi-Fi capability, since users could bypass more expensive cellular
network data offerings. That view is changing due to the rapid growth in demand
for data over mobile cellular networks and consequent capacity constraints. Today,
many mobile operators embrace Wi-Fi as a way to offload 3G-network traffic as a
complement to their regular commercial service. For example, AT&T in the United
States is automatically switching smartphone users to Wi-Fi when they are within
range of a hot spot (Fitchard 2010).
Aside from its role in the international
and backbone segments of the broadband supply chain, satellites are also used to
provide direct subscriber access to broadband services, particularly in remote areas
where wireline broadband is not available and there is no terrestrial high-speed
The subscriber uses a satellite antenna or dish that is connected to a satellite
modem. Speeds vary depending on the satellite technology, antenna, and the weather.
Latency can be an issue for some applications (for example, gaming). Although they
serve specific niches, satellites do not offer the same price to quantity ratio
as other broadband solutions. For example, in March 2011 the highest speed available
from a leading retail broadband satellite provider in the United States was 5 Mbit/s
for US$300 per month.*
184.108.40.206 Local Loop Unbundling
In many countries, an incumbent, former
monopoly wireline provider often controls the only extensive local access network.
In such cases, regulators have sought ways to introduce more competition and innovation
into the local access market. Local loop unbundling (LLU) has been one of the main
methods implemented in developed nations for service providers to gain access to
the incumbent’s switched telephone network in order to provide DSL service. There
are three main types of implementation:
The entire copper local loop is leased to a service provider. The service provider
installs its own broadband equipment either in, or close to, the incumbent’s site.
The copper local loop is shared between the incumbent and the other service provider.
The incumbent provides voice telephony over the lower-frequency portion of the line,
while the other provider offers DSL services over the high-frequency portion of
the same line.
Bit stream access.
DSL service is essentially sold at wholesale prices to the service provider, who
in turn resells it to customers. The incumbent operates all of the key infrastructure
components in the loop.
220.127.116.11 Quality of Service
There is often a significant difference
between advertised speeds and actual speeds achieved by users (Figure 5.13). The
problem is that the advertised speeds are usually based on the theoretical capability
of the technology or standard. In reality, however, numerous factors make such speeds
very difficult or even impossible to achieve, including network congestion or (for
wireless networks) radio interference.
Figure 5.13 Difference between Advertised and Actual Speeds in the United Kingdom, 2009 and 2010
Source: Ofcom, “The Communications Market
2010: UK,” http://www.ofcom.org.uk/static/cmr-10/UKCM-5.10.html.
Note: Headline speeds are based on data from
the operator, while actual speed are based on measurement data from SamKnows for
all panel members with connections in April 2009 and May 2010 (single-thread tests).
In an effort to manage
network quality, many providers are moving away from unlimited broadband packages
and adopting so-called “fair use policies” in order to control and regulate traffic.
One practice is to use data caps where providers establish a threshold on the amount
of data that can be downloaded per month. Once the cap is exceeded, either the subscriber
has to purchase additional download volume or the subscriber’s speed is reduced
or, in the worst-case scenario, service is terminated for that month. Some operators
establish different caps for domestic and international traffic. Another practice
is to control the use of high-bandwidth applications or access to traffic-intensive
sites by restricting or degrading service. This practice has been banned in some
countries as a violation of network neutrality. Providers have been known to “throttle”
service by limiting the subscriber’s bandwidth when they have exceeded data caps
or tried to access traffic-intensive sites.
These network management
practices have been contentious since they are often covered by the “small print”
of customer contracts and many users are not aware of them. In an effort to alleviate
consumer concerns about service quality, some governments monitor and compile reports
on service quality. The Telecommunications Regulatory Authority (TRA) in Bahrain,
for example, publishes data on wireline broadband performance (Bahrain, Telecommunications
Regulatory Authority 2011). The TRA measures upload and download speeds for different
broadband packages, domain name system (DNS) response (time taken in milliseconds
to translate a domain name to its IP address), and ping (an echo request sent to
a server to test latency). In other countries, although governments do not publish
quality of service reports, they offer sites where consumers can check their speed.*
One of the biggest constraints on wireless
broadband deployment and usage is the availability of spectrum. Some countries have
yet to allocate mobile broadband spectrum, have not allocated certain frequencies,
or have not allocated sufficient spectrum.
Although the number of
frequency bands in which mobile broadband operates has increased, not every technology
operates in every band. Therefore, by not licensing certain bands, countries prevent
the availability of some mobile broadband technologies. Another issue is that even
slight differences in frequency assignments can make a difference in equipment compatibility,
affecting prices and roaming. Growing mobile broadband demands are placing increasing
pressure on spectrum availability. Providers use several techniques to increase
capacity, including splitting cells, upgrading to more efficient technology, and
offloading some uses onto other networks like Wi-Fi. However, there may come a point
where technology cannot fix the capacity shortage and additional spectrum is required.
Some countries have already begun examining how to use the various bands identified
for broadband, including the so-called “digital dividend” spectrum that can be made
available as the result of the transition from analog to digital television. One
promising solution could be cognitive radio, where devices reconfigure themselves
according to whatever spectrum is available, while avoiding interference. The first
call in the world using cognitive radio was made in Finland in 2010 (Centre for
Wireless Communications 2010).
In looking at spectrum,
regulators need to determine the best procedure to follow in awarding spectrum,
whether to impose limits on the amount of spectrum a single operator can hold, and
whether to allow operators to engage in secondary trading. These issues are discussed
in more detail in chapter 3.