January 25, 2008
COMMUNICATION – Information Technology and Libraries
WiMAX – Accessing Academic Content Wherever Learners
and Researchers Locate
Bradley D. Faust, M. L. S.
Assistant Dean for Library Information Technology Services
Ball State University
Muncie, IN 47306
Arthur W. Häfner, Ph.D., M.B.A.
Dean of University Libraries
Ball State University
Muncie, IN 47306
Questions concerning this manuscript should be directed to Bradley D. Faust, 765-2858032, BFaust@bsu.edu
WiMAX – Accessing Academic Content Wherever Learners
and Researchers Locate
Abstract
This research report summarizes the test results and potential application of WiMAX
in a higher education environment including links to the academic library. The authors
illustrate how WiMAX connectivity will expand access to online academic content beyond
traditional Ethernet and Wi-Fi network solutions.
The results of two WiMAX technology tests involving content and facilities provided
by the Ball State University Libraries are reported. Test one included streaming digital
library content to measure WiMAX throughput and sustainability. Test two measured
WiMAX signal penetration using the Alexander M. Bracken Library facility as the test center.
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WiMAX – Accessing Academic Content Wherever Learners
and Researchers Locate
Introduction
In 2007 the University Libraries at Ball State University partnered with the
University’s Office of Information Technology (OIT) and the Office of Wireless Research and
Mapping (OWRM) to test WiMAX technology. Credited with bringing Ball State to the top of
Intel’s list of the most unwired campuses in 2005, OIT is expanding research in the wireless
network arena through the efforts of the Office of Wireless Research and Mapping
(Cameron 2005). When OWRM was searching for online content providers and locations to
conduct WiMAX testing, the University Libraries was an obvious choice with its rich digital
content online and the spacious Bracken Library facility.
WiMAX Overview
WiMAX is the acronym for “Worldwide Interoperability for Microwave Access”
(Curran 2007). WiMAX is a set of standards-based wireless network services for providing
high-speed, broadband connectivity to educational institutions, residents, and businesses
(Clearwire Successfully Completes First Phase of Mobile WiMAX Field Trial 2007). It has
been described as “Wi-Fi on steroids” (UK "Wi-Fi on Steroids" 2006). Its promise and
potential is a coverage area measured in miles or kilometers rather than yards or meters.
Just a few WiMAX transmitters, for example, can blanket entire campuses, small towns,
nature research areas, and other “last mile” locations with quality high bandwidth
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networking. In areas that are difficult, costly, or challenging to reach with wired
telecommunications infrastructure, WiMAX is a great technology option for Internet-based
connectivity services.
Development of WiMAX is monitored and directed by the WiMAX Forum, an
industry-based consortium established to promote and certify the compatibility and
interoperability of broadband wireless network access equipment between and among
manufacturers. The WiMAX Forum is concerned with conformance to the IEEE 802.16 set of
standards (Curran 2007). The 802.16e standard, describing Mobile WiMAX, extends WiMAX
solutions to provide broadband network opportunities for users on the move (Curran 2007).
With the ability to operate on many different frequencies, WiMAX can accommodate
existing frequency assignments in both licensed and unlicensed spectrums. At the lower
operating frequencies, WiMAX provides consistent performance in non-line-of-sight (NLOS)
environments. Examples of NLOS environments are heavily populated and green urban
environments where building and plant density can be a factor in signal strength. Green
areas impacting WiMAX performance will have heavy foliage and high tree density.
During the months of January and February 2007, Ball State’s OWRM research team
conducted several WiMAX equipment tests divided into two phases. Phase I work tested
network performance using various system configurations. Librarians in the University
Libraries identified several rich media assets including both digital audio and video formats
for use by the WiMAX test team. This academic content, resources available to and used by
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Ball State students and faculty, provided a real-world scenario as well as a controlled
baseline for WiMAX signal performance testing. The content was consolidated and
published on a web page, www.bsu.edu/libraries/wimax, to provide easy access for the
testing team. WiMAX signal testing involved licensed frequencies in the 3.5GHz range. The
University received special permission from the Federal Communications Commission (FCC)
to work with licensed frequencies (Romano 2006).
Phase II testing involved equipment designed to use WiMAX as a backhaul Internet
link to existing Wi-Fi access points for end-user Hotspot access. According to the Academic
Press Dictionary of Science and Technology, back-haul networks connect or bridge a remote
site to a central site or office. Phase II testing was conducted using the Alexander M.
Bracken Library facility to measure signal strength and overall network performance.
Bracken Library proved to be an excellent test location because it contains a combination of
open and densely-filled spaces on 5 levels, offering space equivalent to seven football fields.
WiMAX Value to the University Libraries’ Community of Users
A major focus for the University Libraries is to provide broad access to the print and
online academic resources demanded by students and faculty for research, learning,
teaching, and classroom enhancement. This fundamental focus supports the stated
objective to strengthen the role of the Libraries in the academic life of the University. In
today’s Google age, students and faculty expect immediate access to online information
resources from the desktop, a wireless laptop, or even a Smartphone device. High-speed
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Ethernet networks on campuses, broadband connections in the home, and Wi-Fi hot spots
in local coffee shops and eateries fuel student and faculty desire and expectation for
anytime, anywhere Internet access.
Internet access and, consequently, access to online academic resources is viewed as
ubiquitous, yet there are important links missing from the chain. Traditional wired data and
voice networks do not provide online access everywhere it is needed. Wi-Fi and cellular
network services stretch the boundaries for wired online connectivity, often with separate
subscription fees and high usage costs. And these wireless networks have boundaries
leaving users under- or un-served, often in the so-called last mile areas. WiMAX technology
brings the promise of reliable broadband connectivity as a cost-effective solution to all user
populations for education, research, and entertainment.
WiMAX and Academic Content Delivery
What impact does WiMAX have on the academic library anyway? A college or
university library dedicates considerable time, effort, and fiscal resources to providing
access to credible online academic content for student learning, faculty research, and
classroom instruction. Much of this rich academic content is licensed for campus
community members to access anywhere. WiMAX holds the promise to connect those
community members to these resources even if they are located in remote or
nontraditional research locations.
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Library services like OpenURL link servers, implemented in the Ball State University
Libraries as FindIt@BSU, connect users with the large, full-text PDF editions of journal
articles and e-book content. These large files require broadband level speeds for fast
download by students and faculty from off-campus Internet connections. WiMAX addresses
this requirement.
Digital library collections contain valuable digital assets representing physical
artifacts in geographically diverse, hard-to-access collections. These digital assets can be
searched, displayed, played, or reviewed from any computer on a wired or wireless
network. As digital library collections grow and expand, WiMAX will serve as one of the
conduits that connect these online assets to the classroom, office, home, or the laptop on
the road. At the Ball State University Libraries, the Digital Media Repository
(http://libx.bsu.edu) and the Cardinal Scholar Institutional Repository system
(www.bsu.edu/cardinalscholar) are digital library systems holding valuable digital content
today.
The primary user groups for the University Libraries’ digital collections are students,
faculty, and staff. Included in this group are teacher education majors and students in the
Burris Laboratory School and Indiana Academy for Science, Mathematics, and Humanities,
primary and secondary schools operated by the University. Many new digital resources
coming online naturally support primary and secondary curriculum for K-12 teachers,
national and international researchers, and community members in important new ways.
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Often the locally produced material in digital collections is of great value to those studying a
region for historical, educational, or planning purposes. Connecting both the primary user
group and other constituents to the digital materials provided by a University and its
libraries is enhanced by WiMAX. WiMAX provides another connectivity option for distance
education students, commuters, and campus network engineers who are seeking reliable,
robust, cost-effective alternatives to network services.
WiMAX Use Scenarios
With a signal range up to 30 square miles, WiMAX extends network connectivity and
Internet access opportunities. WiMAX connects the high speed Internet access we depend
on at work and school to any location in a coverage area. Throughout the day, we all
experience moments where we could do one more e-mail, complete one more task, or
respond to one more colleague if we only had easy Internet access to our home or work
computer. With a laptop in hand, imagine being online instantly wherever you are. Easy
Internet access wherever you are is the reality of WiMAX.
In a WiMAX coverage area, personal banking information, primary research material,
or popular social networking web sites, destinations containing information that is
important and valuable to us, is always available. One of the conditions of WiFi is the
requirement to be in a relatively small hotspot area to have connectivity with a laptop or
other handheld mobile device. This is not so with WiMAX. The WiMAX coverage area is
relatively large! And while we can check e-mail and watch video from a mobile phone,
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security certificates and content rich pages from many web sites don’t work well on
handheld devices limiting the usefulness of these units. WiMAX provides full, broadband,
content-rich Internet access to notebook computers that will run these pages anywhere in
the 30 square miles of the coverage area.
WiMAX can serve as a community economic development tool in several ways.
First, community members enjoy easy Internet access throughout the area. WiMAX may
also eliminate the requirement for individual businesses to buy and build dedicated Wi-Fi
hotspots. In cities with downtown areas attempting to revitalize and attract new
businesses, WiMAX-based Internet access can be an important commodity just like street
lights and fire hydrants.
Phase I Testing – University Libraries’ Resources as a Data
Source
WiMAX Streaming Media Test Using the University Libraries’ Content
Introduction
The importance of testing the capabilities of WiMAX technology becomes apparent
when reading the many articles touting high bandwidth technologies such as Internet
Protocol Television, commonly referred to as IPTV (She 2007). These articles mention the
“triple play” of network services which are video, voice, and high-speed Internet (Francis
2006). One of these service segments, video - whether IPTV, video on demand (VOD), or a
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download video service - is of interest to libraries as they expand into online content
providers in areas other than print. Research suggests that there may be as many as 80
million IPTV subscribers by the year 2011 (IPTV News 2007). Considering this real demand,
testing video content availability and delivery via WiMAX was determined by the Ball State
University test team to be an important issue to examine.
Purpose
The purpose of this exercise was to obtain test data to provide insight into the ability
of WiMAX wireless technology to effectively deliver streaming video. The availability of
streaming video content via Ball State University Libraries’ servers provided excellent test
data since such a service requires the organization to consider several network factors. For
example, streaming media is susceptible to excessive latency, jitter, packet loss, and packets
delivered out of order. This test phase focused on measuring and recording the available
performance statistics while streaming library video over the WiMAX network. Such
statistics were then analyzed to assess the capabilities of the technology.
Test Methodology
Two tests were performed. The first utilized the outdoor test deployment of the
WiMAX equipment. Performance of the technology in this setting was susceptible to all
factors in the environment. The second test was performed with the same equipment in a
controlled lab setting. This inside setting most closely represented the ideal environment
for a wireless network implementation.
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Phase I Test Results
The outdoor tests utilized video assets encoded in 700Kb/s and 2Mb/s streams.
During this testing, snow was falling at a rate of about 1 to 1.5 inches per hour. Students
randomly walked around the subscriber unit during the testing. The subscriber unit was
positioned about eight inches off the floor near a metal framed glass door. Because the
signal to and from the base station was reflected off other buildings and structures, non-line
of site (NLOS) as a performance factor was successfully addressed.
These conditions provided an insignificant degree of difficulty delivering the library
streaming video. The results included maximum burst error rates of 0.0058% and an
average burst error rate of .0018%. Discarded data bytes on the uplink measured
0.0000114% while discarded data bytes on the downlink were at 0.00192%. In other
words, the WiMAX link did not impact the delivery or quality of the digital video playback.
The lab testing did not reveal any issues with either the 700Kb/s or 2Mb/s video
assets. Testing a 4Mb/s stream revealed only minimal issues but nothing significant. Data
discards on the downlink measured 0.000341% and no discards were noted on the uplink.
Phase I Test Conclusions
Phase I testing demonstrates the WiMAX network provides adequate throughput
and performance for delivering streaming media encoded up to 4Mb/s. At a 4Mb/s
encoding rate, the stream represents half of the total available throughput. Burst errors
and discarded data bytes by the hardware were minimal or non-existent and packet loss
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was all but non-existent. The result is that high quality digital video assets can be
successfully streamed with WiMAX without any noticeable artifacts, pauses, audio/video
synch issues, or re-buffering activity. These conclusions are made with regard to the
previously mentioned movement and weather conditions.
The results of these tests do not by themselves guarantee the necessary
performance to deliver quality streaming media such as video on demand or IPTV over
WiMAX. However, we believe they do speak positively to the potential of serving the
network needs of large populations with WiMAX technology (McCoy 2007).
Phase II Testing – User Access and WiMAX Equipment
Performance
WiMAX Antenna Comparison Tests at Alexander M. Bracken Library
Introduction
The first Phase II test was to determine how well the Alvarion Wi2 penetrates a
building with an Omni directional antenna. This test was then repeated using a 120°
directional antenna with 14dBi of gain and 7° vertical beam width. The second Phase II test
recorded the measurements at the same locations as the first test using an Omni directional
diversity antenna. The Wi2 unit was installed at the same location and distance as in the first
test. The output was recorded on the same map as were the results from the first test. This
will provide a quick review of the signal variance between the tests using the different
devices.
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Assumption for results of second test
Testing the signal strength using the directional antenna gave readings that were
much better than with the Omni directional antenna. Using a narrow beam to cover an
area, more radio frequency (RF) is concentrated in a controlled location. As testing
continued on upper floors, the signal reading improved compared to the first test, yet not
as proportionally as on the first floor. The directional antenna provided better readings at
identical locations although it did not offer much additional “in building” coverage
compared to the Omni directional antenna. The exception was on Bracken Library’s first
floor where the coverage area was greater throughout using the directional antenna.
One
limitation of
this test was
the height and
placement of
the directional
antenna. It was
in the same
location as that
of the Omni
directional antenna to compare same location signal strength. A limitation of this particular
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installation is that, based on the vertical beam width of 7º , half of the power of the antenna
intersects the building at a height of 18 feet, and 25% of the signal is absorbed by the
ground. To have optimal coverage in the building, the directional antenna would need to be
installed 400 feet away and at a height of 20-25 feet. Unfortunately, the test team was not
equipped to perform a test with these conditions. The results indicated, in general, that the
directional antenna would be better suited to provide service to this particular building.
Conclusion
As Ball State University actively explores new technologies with the objective of
improving the delivery of electronic educational services and information resources, WiMAX
is positioned to become a cost effective, high performance broadband platform for
extending network connectivity. As populations increasingly demand to be connected while
they are on the move anywhere and anytime, wireless communication and technology
companies are investing in and testing WiMAX for content distribution. As WiMAX
technology matures and becomes more widely implemented, it will provide a significant
opportunity for libraries and their parent institutions to deliver educational services and
learning opportunities, including dynamic online information resources, to learners and
scholars.
Cameron, L. Newscenter Web Site. 2005. http://www.bsu.edu/news/article/0,1370,37100-,00.html (accessed May 11, 2007).
Clearwire Successfully Completes First Phase of Mobile WiMAX Field Trial. Kirkland, May 21,
2007.
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Curran, K, et al. "An overview of Worldwide Interoperability for Microwave Access." Journal
of Information Technology Impact, 2007: 1-14.
Francis, J. Charles, Elnegaard, Nils, Eskedal, Thor Gunnar, Venturin, Rima. "Business
Opporutnies of Open Broadband Wireless Access Networks." Proceedings of the 2006
workshop on Broadband wireless access for ubiquitous networking. Alghero: ACM, 2006.
IPTV News. January 31, 2007. http://www.iptv-news.com/content/view/1012/64/ (accessed
January 24, 2008).
McCoy, Brad, and Boyd, Trent. WiMAX Technology Evaluation. Research, Muncie: Ball State
University, 2007.
Romano, Anthony. Ball State University News Center. November 27, 2006.
http://www.bsu.edu/alumni/article/0,1384,280237-17607-48523,00.html (accessed
October 26, 2007).
She, James, Hou, Fen, Ho, Pin-Han, and Xie, Liang-Liangl. "IPTV over WiMAX: Key Success
Factors, Challenges, and Solutions." IEEE Communications Magazine, 2007: 87-93.
"UK "Wi-Fi on Steroids"." Library Journal 131, no. 8 (May 2006): 30.
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