What is Cognitive Radio?

A cognitive radio (CR) is an intelligent radio that can be programmed and configured dynamically. Its transceiver is designed to use the best wireless channels in its vicinity. Such a radio automatically detects available channels in wireless spectrum, then accordingly changes its transmission or reception parameters to allow more concurrent wireless communications in a given spectrum band at one location.

This process is a form of dynamic spectrum management. In response to the operator’s commands, the cognitive engine is capable of configuring radio-system parameters. These parameters include “waveform, protocol, operating frequency, and networking”. This functions as an autonomous unit in the communications environment, exchanging information about the environment with the networks it accesses and other cognitive radios (CRs). A CR “monitors its own performance continuously”, in addition to “reading the radio’s outputs”; it then uses this information to “determine the RF environment, channel conditions, link performance, etc.”, and adjusts the “radio’s settings to deliver the required quality of service subject to an appropriate combination of user requirements, operational limitations, and regulatory constraints”.

Some “smart radio” proposals combine wireless mesh network—dynamically changing the path messages take between two given nodes using cooperative diversity; cognitive radio—dynamically changing the frequency band used by messages between two consecutive nodes on the path; and software-defined radio—dynamically changing the protocol used by message between two consecutive nodes. J. H. Snider, Lawrence Lessig, David Weinberger, and others say that low power “smart” radio is inherently superior to standard broadcast radio.

Cognitive radio (CR) is a paradigm for opportunistic access of licensed (primary) parts of the electromagnetic spectrum by unlicensed (secondary) users. This emerging technology is aimed at improving the efficiency of wireless resource usage. In medical environments, CR has big potential to solve interference problems caused by the scarcity of spectrum allocated to medical applications. Hospital environments such as the operating room (OR) offer challenging scenarios to spectrum managers, in which CR is a viable solution to ensure electromagnetic compatibility (EMC). A recent trend in medical practice is the use of wearable wireless medical sensors. These devices are being introduced in unlicensed bands, where the usual concepts of primary and secondary users do not apply. This paper discusses some of the alternatives for implementing CR in such particular environments. A short survey of CR for hospital environments is also presented, highlighting the differences with the scenarios in which wireless sensors are used.