WIRELESS SYSTEMS

CELLULAR PHONES:
There are two types of technology available in mobile phones. They are
1.GSM
2.CDMA
GSM:
It stands for Guided Subscriber Module which consists of SIM card. SIM stands for Subscriber Identifier Module. It requires Base station to be erected between particular distances to receive and transmit signals.

CDMA:
It stands for Coded division Multiple access. It does not require SIM to operate. Each mobile is inbuild with subscriber identification within itself. The frequency range for CDMA is high and therefore Base station required is lesser when compared to GSM.

WIRELESS LANs:
Infrared or radio links.

ADVANTAGES:

1.Very flexible within the reception area.
2.Ad-hoc networks possible.
3.(almost) no wiring difficulties.

DISADVANTAGES:

1.Low bandwidth compared to wired networks.
2.Many proprietary solutions.



BLUETOOTH:

CONSORTIUM:
Ericsson, Intel, IBM, Nokia, Toshiba - many members.

SCENARIOS:

Connection of peripheral devices like
loudspeaker, joystick, headset

Support of ad-hoc networking
Small devices, low-cost.

Bridging of networks
e.g., GSM via mobile phone - Bluetooth - laptop