Software Radio & its Implementation Issues

Software radio is not a new technology but it has gained a lot of interest over past few years. SDR is a radio that derives its flexibility through software while using a static hardware platform, this feature has apparently made it a credible option for future wireless communications thereby making software radio a wireless communication device in which all of the signal processing is implemented in software. By simply downloading a new program, a software radio is able to interoperate with different wireless protocols, incorporate new services, and upgrade to new standards. In this paper we are discussing the issues involved in practical implementation of this approach. The first issue is the ability to convert from analog to digital (A-D) signals. If A-D conversion can take place immediately at the antenna, then all functions within the radio can be done digitally (i.e. in software). Second issue is the timing and synchronization required within the radio. It is required to handle the bit rate throughout the radio system which is a key factor in determining the performance of the radio. It is critical for maintaining the integrity of information throughout the radio. Third issue is the interface to RF transmission domain. Antennas propagate signals differently based on the frequency of the signal being transmitted and optimizing RF signal propagation is therefore frequency dependent. As it turns out, it is difficult to design antennas over a wide range of frequencies. This complicates the radio design as well as the antenna design, particularly if multiple input and multiple output antennas are used for art of the transmission process.