Software Defined Radio - Defined:
A number of definitions can be found to describe Software Defined Radio, also known as Software Radio or SDR. The SDR Forum, working in collaboration with the Institute of Electrical and Electronic Engineers (IEEE) P1900.1 group, has worked to establish a definition of SDR that provides consistency and a clear overview of the technology and its associated benefits.
Simply put Software Defined Radio is defined as:
"Radio in which some or all of the physical layer functions are software defined"
A radio is any kind of device that wirelessly transmits or receives signals in the radio frequency (RF) part of the electromagnetic spectrum to facilitate the transfer of information. In today's world, radios exist in a multitude of items such as cell phones, computers, car door openers, vehicles, and televisions.
Traditional hardware based radio devices limit cross-functionality and can only be modified through physical intervention. This results in higher production costs and minimal flexibility in supporting multiple waveform standards. By contrast, software defined radio technology provides an efficient and comparatively inexpensive solution to this problem, allowing multimode, multi-band and/or multi-functional wireless devices that can be enhanced using software upgrades.
Software Defined Radio - Related Technologies
SDR can act as a key enabling technology for a variety of other reconfigurable radio equipments commonly discussed in the advanced wireless market.
While SDR is not required to implement any of these radio types, SDR technologies can provide these types of radio with the flexibility necessary for them to achieve their full potential, the benefits of which can help to reduce cost and increase system efficiencies:
Adaptive radio is radio in which communications systems have a means of monitoring their own performance and modifying their operating parameters to improve this performance. The use of SDR technologies in an adaptive radio system enables greater degrees of freedom in adaptation, and thus higher levels of performance and better quality of service in a communications link.
Cognitive radio is radio in which communication systems are aware of their internal state and environment, such as location and utilization on RF frequency spectrum at that location. They can make decisions about their radio operating behaviour by mapping that information against predefined objectives.
Cognitive radio is further defined by many toutilize Software Defined Radio, Adaptive Radio, and other technologies to automatically adjust its behaviour or operations to achieve desired objectives. The utilization of these elements is critical in allowing end-users to make optimal use of available frequency spectrum and wireless networks with a common set of radio hardware.
As noted earlier, this will reduce cost to the end-user while allowing him or her to communicate with whomever they need whenever they need to and in whatever manner is appropriate.
Intelligent radio is cognitive radio that is capable of machine learning. This allows the cognitive radio to improve the ways in which it adapts to changes in performance and environment to better serve the needs of the end user.
These types of radio – adaptive radio, cognitive radio and intelligent radio – do not necessarily define a single piece of equipment, but may instead incorporate components that are spread across an entire network.