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Unit 9: The Wireless Revolution

typically for broadband Internet access. It uses multiplexing techniques including code division Notes
multiple access (CDMA) as well as time division multiple access (TDMA) to maximize both
individual user’s throughput and the overall system throughput. It is standardized by 3rd
Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and has
been adopted by many mobile phone service providers around the world – particularly those
previously employing CDMA networks. It is also used on the Globalstar satellite phone network.
EV-DO was designed as an evolution of the CDMA2000 (IS-2000) standard that would support
high data rates and could be deployed alongside a wireless carrier’s voice services. An EV-DO
channel has a bandwidth of 1.25 MHz, the same bandwidth size that IS-95A (IS-95) and IS-2000
(1xRTT) use. The channel structure, on the other hand, is very different. Additionally, the back-
end network is entirely packet-based, and thus is not constrained by the restrictions typically
present on a circuit switched network.
The EV-DO feature of CDMA2000 networks provides access to mobile devices with forward link
air interface speeds of up to 2.4 Mbit/s with Rev. 0 and up to 3.1 Mbit/s with Rev. A. The reverse
link rate for Rev. 0 can operate up to 153 kbit/s, while Rev. A can operate at up to 1.8 Mbit/s. It
was designed to be operated end-to-end as an IP based network, and so it can support any
application which can operate on such a network and bit rate constraints.
EVDO, also known as EV-DO, 1xEvDO and 1xEV-DO, is a standard for high speed wireless
broadband. The acronym is short for “Evolution, Data Only” or “Evolution, Data Optimized”.
The official name, defined by the Telecommunication Industry Association, is “CDMA2000,
High Rate Packet Data Air Interface”. It is one of two major Third Generation, or 3G, wireless
standards. The competing standard is known as W-CDMA.

3G is designed to provide voice and high-speed mobile data using the cellular approach already
proven to work in mobile phone networks. The biggest obstacle to implementing high speed
wireless networks is the lack of bandwidth, or range of usable frequencies. Just as only so many
radio stations can be squeezed onto the FM dial, only so much data can be transmitted across the
available bandwidth. EVDO is an advanced CDMA technology developed by Qualcomm to deal
with this limitation.
CDMA, Code Division Multiple Access, uses advanced mathematical techniques to allow multiple
wireless devices to transmit simultaneously on the same frequency. Every device, such as a cell
phone, is assigned a unique mathematical signature. It applies this signature to the original
signal and transmits the modified signal. A receiver applies the inverse of the mathematical
operation to recover the original signal.

Traditional wireless networks create a physical path between receiving and sending devices,
much like traditional telephone networks. EVDO instead adopts the same approach used for the
internet. IP, the Internet Protocol, breaks data into small pieces called packets. Each packet is
sent independently of all the other packets. This saves bandwidth for use by other devices; when
neither party on a phone call is speaking, the connection consumes no bandwidth because there
are no packets to send. Or, when an internet web site is accessed, no bandwidth is used until the
site starts sending the web page.
EVDO has a theoretical throughput of 2.4 megabits per second. This is as fast as many residential
DSL and cable broadband connections currently available in the United States. Qualcomm has
produced impressive demonstrations of EVDO’s capabilities; in one, a video conference was
conducted with a participant traveling in a car at 60 miles per hour (96 km/hour). In another
demonstration, a phone call was placed from a bullet train moving in excess of 150 miles per
hour (240 km/hour).

A significant advantage of EVDO over competing technologies is that it uses the same broadcasting
frequencies as existing CDMA networks. As purchasing spectrum from regulatory agencies is

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