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Unformatted text preview: ipment that are equipped
with a modem can transfer data over analog cellular telephone networks. Although
the data rates supported by this technology are low (of the order of few Kbps), it is
one of the most popular methods for wireless data communications due to the
wide availability of modems and analog cellular services.
By using this communication technology, computing equipment can transfer
digital data over digital cellular telephone networks without the need for a modem.
The various standards available for digital cellular c transmission are
1. Time Division Multiple Access (TDMA),
2. Code Division Multiple Access (CDMA), and
3. Global System for Mobile Communication (GSM). The effective data transfer rate of digital cellular technology is less than that of
analog cellular technology.
Cellular Digital Packet Data (CDPD)
In this method, digital data to be transferred is broken into small packets and
inserted into analog cellular telephone networks. The technology employs unused
analog channels available in the analog telephone cellular infrastructure. That is,
transmitters use a channel for a short transmission burst and release the channel
for analog voice links. The effective data rate that can be achieved using this
technique is 19.2 Kbps.
Mobile Radio Networks
The Specialized Mobile Radio (SMR) and Extended Specialized Mobile Radio
(ESMR) technologies employ narrow bands for creating mobile radio network
infrastructure. Such an infrastructure is primarily used for utility, dispatch, and
other service-oriented metropolitan area users. Due to the use of narrow bands,
mobile radio networks have limited data rates (of the order of 20 Kbps).
Personal Communications Services (PCS)
PCS technology is used to offer greater network complexity and lower end-to-end
latency in wireless networks. It has two variations. The low-tier PCS is used for
microcell coverage for frequency reuse and low-power benefits. On the other
hand, the high-tier PCS is used for early digital cellular systems such as GSM,
TDMA, and CDMA. It is used for large macrocells of the order of 0.5 and 3.0
kilometers. PCS technology may be use...
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- Spring '14