Assignment : WiMAX VoIP Solution– A Cost-Efficient Way of Communication
Dr. Mashiur Rahman
North South University, Dhaka.
WiMAX VoIP Solution– A Cost-Efficient Way of Communication
Riaz Rahman , North South University, Dhaka, Bangladesh.
Abstract— With the fast development of the global WiMAX market, how to provide the
same service experience to the traditional telecom domain on WiMAX network becomes
a principal problem.Voice over IP is an important application drive for WiMAX
adoption, as voice has become a powerful tool when it is enabled across a wireless
platform. Voice over WiMAX has requirements on a high degree of mobility, wireless
access, and quality service. What is really interesting about WiMAX VoIP is that it offers
a cost structure potentially. VoIP and WiMAX are converging toward a powerful
wireless voice solution for the individual, family, or enterprise applications.
In most networks, voice traffic travels over a public switched telephone network (PSTN),
while workstation and application data travels over an IP-based wide area network
(WAN). However, converged network carries both traditional data such as e-mail, FTP,
and business applications, as well as voice traffic such as telephone calls, teleconferences,
and voice mail. Most data networks use the Internet Protocol (IP) as the networking
standard for connecting their LANs and WANs. Voice traffic carried by an IP-based
network is referred to as Voice over IP (VoIP).
WiMAX, or Worldwide Interoperability of Microwave Access, is a wireless Internet
service designed to cover wide geographical areas serving large numbers of users at low
cost. WiMAX is the synonym given to the IEEE 802.16 standard defining wide area
wireless data networking. WiMAX is the standard being adopted worldwide by
manufacturers to insure inter-operability of equipment. WiMAX is considered one of the
best solutions for “last mile” distribution. Wimax is an emerging wireless networking
technology that offers the potential for higher data rates than wireless LAN technologies
such as Wi-Fi -- and over much greater distances: tens of kilometers, instead of tens of
meters. Wimax standards are still under discussion, however. The standard for fixed
terminals is the most advanced, but other standards for portable and mobile terminals are
also in development.
A WiMAX infrastructure will let service providers deliver VoIP to rural areas without a
backhoe. WiMAX technology to provide VoIP and data services to rural areas to avoid
local access charges.VoIP over WiMAX is attractive for both enterprises and carriers, but
challenges remain. The initial WiMAX equipment will be certified in the 2.5- and 3.5-
GHz spectrum ranges. The 2.5-GHz spectrum is owned largely by Sprint and Nextel,
while the 3.5-GHz spectrum is not available for use in the United States. This means that
any near-term WiMAX equipment deployment will likely use unlicensed spectrum,
which carries the risk of interference from other wireless devices. VoIP over WiMAX
can be made reliable and cost-effective.
II. Benefit of WiMAX VoIP
WiMAX delivers a cost-effective alternative to broadband access. Since many
businesses, organizations and communities are not zoned for cable, the local telecom
company provides the only option for broadband service. The ease of deployment for
WiMAX systems can benefit customers by bringing new competition into the
marketplace and lowering prices, or by enabling enterprises and higher-educational
institutions to set up their own private networks. The added benefit that remote WiMAX
VoIP users need less or no on-site installation significantly reduces the cost and set-up
time of delivering the service, allowing it to favorably compete with existing cable or
other wired solutions.
III. WiMAX VoIP INFRASTRUCTURE
A new, more complex and fully developed standard would be required to address both
the physical layer environment (outdoor versus indoor RF transmissions) and the Quality
of Service (QoS) needs demanded by VoIP over WiMAX.The IEEE conducted a multi-
year effort to develop this new standard, culminating in final approval of the 802.16a Air-
Interface Specification in January 2003. This standard has since received broad industry
support from leading equipment makers. Many WiMAX company members are active in
both the IEEE 802.16 standards development and the IEEE 802.11 efforts for VoIP over
WiMAX, and envision the combination of 802.16a and 802.11 creating a complete
wireless solution for delivering high speed Internet access to businesses, homes, and
WiFi hot spots.
Fig.1. WiMAX VoIP infrastructure
Acronyms and Abbreviations
AAA: Authentication, Authorization and Accounting PSTN: Public Switched Telephone Network
ASN: Access Service Network QoS: Quality of Service
ASN-GW: Access Service Network Gateway RRM: Radio Resource Management
BS: Base Station VLAN: Virtual Local Area Network
CSN: Connectivity Service Network VoIP: Voice over IP
FA: Frequent Assignment VPN: Virtual Private Network
IP: Internet Protocol Wi-Fi: Wireless Fidelity
IPSec: IP Security Protocol LAN: Local Area Network
WiMAX: Worldwide Interoperability for Microwave Access Forum
The 802.16a standard delivers carrierclass performance in terms of robustness and QoS
and has been designed from the ground up to deliver a suite of services over a scalable,
long range, high capacity "last mile" wireless communications for carriers and service
providers around the world.
In WiMAX VoIP, applications include residential broadband access-- DSL-level service
for SOHO and small businesses, T1/E1 level service for enterprise, all supporting data,
voice and video as well, wireless backhaul for hotspots and cellular tower backhaul
service to name a few.
In reviewing the standard, the technical details and features that differentiate WiMAX
certified equipment from WiFi or other technologies can best be illustrated by focusing
on the two layers addressed in the standard, the physical (PHY) or RF transmissions and
the media access control (MAC) layer design.
IV. IMPLEMENTION OF WiMAX VoIP
In 2004, Ertach deployed “The First WiMAX Network in Latin America,” providing
internet access, data transmission, and Voice over Internet Protocol (VoIP) with the
standard 802.16d. Another important milestone for Ertach was the launch of the first
Portable Broadband Network in Latin America with WiMAX Technology in August
2006. The network was launched in the city of Carlos Casares, providing broadband
internet access and VoIP to one of the largest agro-business company in Argentina and to
remote communities and enterprises in rural and suburban areas.The company has
invested more than US$23 million in the development and continuous expansion of its
WiMAX network countrywide.
VoIP over Pre-WiMAX has been successfully tested in a trial in South Africa utilizing
solutions supplied by Verso Technologies and Saab Grintek Technologies. The trials
involved Wi-Fi-compatible PDAs obtaining access to the public switched telephone
network (PSTN) via customer premise gateways. Backhauling of WiMAX technology to
an existing Telkom South Africa was accomplished through customer premise gateways.
Softswitching and gateway technologies were used to deploy the test.
V. PROPOSED WiMAX VoIP PLANNING FOR
Bangladesh has a lot of opportunities to use WiMAX VoIP to provide better and cost
effective services in health care sector, telemedicine, agriculture sector, interviews for
job, audio-visual conferences in public and private organization, computer training, e-
commerce, garments sector, banks, public exams etc. These services will mostly help the
poor people living in the rural area.
Some multi purpose service centers are needed to be established in different places all
over the country. In these service center most of the above services can be provided. The
target country Bangladesh is divided into six divisions. Initially six service centers can be
established in six divisional head quarters. Later district, union and thana level can be
brought under this system. All of the service centers will be connected to each other
through a control center (Star topology). Later the network could be expanded up to thana
level to make the system more convenient and effective. Figure 2 illustrates the
infrastructure of the network system. The control center will be responsible for the task
allocation and overall management of the service centers. High speed communication is
very essential between the control center and the service centers. Existing Fiber optic
backbone throughout Bangladesh could provide a very high bandwidth communication
between the control center and the service centers. Service centers should have all the
cutting edge facilities of the modern technology. Each center will be equipped with
modern VoIP equipment. One center may contain about 100 personal computers
connected on LAN fashion, Internet, database server, audio-visual facilities etc. Fig. 3
illustrates the typical configuration of an service center. The divisional service centers
could act as the control center for all the districts under the division. The centers under
one division will form a LAN to communicate with each other. The medium of the LAN
will depend on the terrain and environmental conditions. Several alternatives, such as
ADSL, 3G wireless, LMDS exist. It is believed that WiMAX can provide an excellent
solution for last-mile distribution with speeds up to tens of Mbps. Generally, the
microwave link will be more preferable than the VSAT link because of the cost-
Fig. 2. The proposed service infrastructure showing the control center with six divisional
cities along with the districts under them
The service centers could provide a number of services to the citizens of the country. The
service centers can promote development of telemedicine network in Bangladesh,
establishment of a virtual medical library, computer literacy programs for medical
professionals and health training for mass people. These centers could be used for various
technical training and educational purposes. Young people can be trained to develop
professional software, as the global software market is open for all, these people can sell
their software globally. About 50% population of Bangladesh are women but their
contribution in national development is significantly low. The government already took
some steps to improve these conditions. service centers can also be a part of these
improvements. These centers can be used to train women and help them to become
effective human resource for the country. Service centers can be used on this purpose
also. Garment sector of the country has now become an over 2.5-billion-dollar-foreign-
exchange-earner, enjoying the status of 5th largest garment exporter and largest shirt and
T-shirt exporter to the EU and 6th largest apparel exporter to USA. Bangladesh now
exports ready-made garments to as many as 30 countries of the world with EU as the
major importer, followed by USA, the largest importing country. Most of the garment
industries are Dhaka (Capital of Bangladesh) centered. So VoIP over WiMAX is the best
solution for deployment of garment sector rural areas of the country for national
communication and international communication between importer and exporter.
Fig. 4: Service center configuration.
In this paper, a cost effective WiMAX VoIP infrastructure has been proposed.
Ultimately, the technical challenges can be addressed and the market opportunity for
WiMAX VoIP service can then begin to develop in Bangladesh.
 Text Book: VoIP for Dummies
 Text Book: Voice over IP technologies- Mark A. Miller, P.E