3. Advantages and Applications Spread Spectrum Communication
The SS Communications are widely used today for Military, Industrial, Avionics, Scientific, and Civil uses. The applications include the following:
- Jam-resistant communication systems
- CDMA radios: It is useful in multiple access communications wherein many users communicate over a shared channel. Here the assignment of a unique spread
spectrum sequence to each user allows him to simultaneouly transmit over a common channel with minimal mutual interference. Such access technique often simplifies
the network control requirements considerably.
- High Resolution Ranging: SS Communications is often used in high resolution ranging. It is possible to locate an object with good accuracy using SS techniques. One example where it could be used is Global
Positioning System (GPS). Here an object can use signals from several satellites transmitting SS signals according to a predefined format to determine
its own position accurately on the globe.
- WLAN: Wireless LAN (Local Area Networks) widely use spread spectrum communications. IEEE 802.11 is a standard that is developed for mobile communication,
and widely implemented throughout the world. The standard defines three types of Physical Layer communications. These are:
- Infrared (IR) Communications
- Direct Sequence Spread Spectrum Communications
- Frequency Hopping Spread Spectrum Communications.
Among the three, DSSS, and FHSS are widely used.
- Cordless Phones: Several manufacturers implement Spread Spectrum in Cordless phones. The advantages of using spread spectrum in cordless phone include the
- Security: Inherently, a ss communication is coded.
- Immunity to Noise: SS modulation is immune to noise when compared with other modulation schemes such as AM and FM.
- Longer Range: Due to noise immunity, it is possible to achieve a longer range of communications, for a very small transmitted power.
- Long-range wireless phones for home and industry
- Cellular base stations interconnection.