21.16 Summary In this chapter we provided an overview of the wireless local area networks
(WLANs). We divided WLAN standards into IEEE 802.11 connectionless and
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ETSI HIPERLAN/2 connection-oriented networks. HIPERLAN/2 is useful for
variable QoS support. IEEE 802.11 WLAN uses FHSS and DSSS techniques to
offer data rates up to 11 Mbps.
Bluetooth is a digital wireless data transmission standard in the 2.4 GHz
ISM band aimed at providing a short-range, wireless link between laptops, mobile
phones, and other devices. The IEEE 802.11 WLANs also operate in this fre-
quency band. Since both systems operate in the same frequency band, interference
between them is caused. We evaluated the performance of the Bluetooth MAC
layer when Bluetooth radio operates in close proximity of other Bluetooth pico-
nets and IEEE 802.11 WLANs. A probabilistic approach was suggested to obtain
the packet error rate (PER) of a Bluetooth piconet and the aggregated throughput
of
N collocated piconets.
The chapter concluded by providing a brief description of the IEEE 802.16
standard for metropolitan area networks (MAN) and highlighting the features of
the WiMAX.
OFDM
Pilot
Subchannel 1
Subchannel 2
OFDM carrier
OFDMA
Figure 21.24 OFDM and OFDMA in 802.16e. 21.16 Summary 773 Ch21-P373580.indd 773
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774 21 Wireless Local Area Networks Problems 21.1 What are the application fi elds of a WLAN?
21.2 Discuss WLAN topologies.
21.3 What are the two network architectures for the WLAN defi ned in the
IEEE 802.11 standard? Discuss them briefl y.
