With increasing demands for varied wireless services, the ease with which radio devices can be modified has become highly important. One solution to this is the use of SDR. Wireless Innovation Forum, which was founded in 1996, works in collaboration with IEEE to develop and promote streamlined work in the field of SDR. Software Defined Radio (SDR), in the simplest of terms, may be understood as a communication system where processing functions like modulation, filtering, amplifying and so on is performed by means of software either completely or partially. Some of the most influential projects which have contributed in giving the current shape to SDR technology are tabulated in Table B.1.

Advantages provided by SDR:

• • SDR can easily upgrade to support any future technique. This permits new technologies to be easily implemented and introduced in the market.

• • SDR allows remote re-programming and remote software downloads, which in turn reduces the cost and time of maintenance while significantly increasing the capacity.

• • As processing is implemented using software, SDR can help in establishing an advanced testing environment without the need of building any physical circuit.

• • SDR can offer capabilities of multi-band, multi-standard and multi-service system just by modifying the software package.

• • SDR enables addition of new features to the already existing infrastructure, thus, reducing the cost of new infrastructure establishment.

Types of SDR:

SDR can be one of the following types depending upon the area in which SDR is implemented:

• 1. Multi-channel systems: Systems that can support the processing of more than one transmit or receive channels simultaneously are multi-channel systems