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CONTENTS
• INTRODUCTION • SOFTWARE-DEFINED RADIO
• Introduction• Evolution of Software-defined Radio
• COGNITIVE RADIO• Introduction• Required Capabilities • Applications
• CONCLUSIONS• REFERENCES
INTRODUCTION
Data communication networks are a vital component of any modern society - extensively used in applications like financial transactions, social interactions, education, national security and commerce.Growing number of data applications and users – Diverse services, different performance requirements.
SOFTWARE-DEFINED RADIOINTRODUCTION :
Since its introduction in 1991, SDR (Software-defined Radio) has been defined as a radio platform of which the functionality is at least partially controlled or implemented in software.
A Digital Radio
Antenna – Receives data
RF front end – Converting into the Intermediate Frequencies
ADC/DAC – Analog to digital conversions
DDC/DUC – Digital-up conversion and Digital-down conversion for modulation and demodulation
Baseband Processing – implements the link layer protocol and performs other operations
-> Joseph Mitola – 1993 – Published an article-> Mid 1990s – military radio – SPEAKeasy (I , II)-> Late 1990s – Started to spread to the commercial sector – most obvious target – cellular networks-> 2005 – A US based company Vanu Inc., came up with a GSM based station AnywaveTM
Evolution:
Definition:
In his , “Cognitive Radio: Brain-Empowered Wireless Communications”, IEEE J-SAC, Feb. 2005, S. Haykin defines a cognitive radio “Capable of being aware of its surroundings, learning and adaptively changing its operation parameters in real time with the objective of providing reliable, anytime, anywhere and spectrally efficient communication.”
COGNITIVE RADIO
An intelligent wireless communication systemBased on SDR technology
ReconfigurableIntelligent adaptive behavior
Aware of its environmentRF spectrum occupancyNetwork trafficTransmission quality
Learns from its environment and adapts to new scenarios based on previous experiences
Key Applications
Allow radios operating on different protocols and standards to communicate with each other – interoperabilityThey are capable of transmitting in unoccupied wireless spectrum while minimizing interference with other signals in spectral vicinity – Dynamic Spectrum Access
CONCLUSIONS
Cognitive radios employ latest advances in microprocessor technology to enable highly flexible wireless devices. They possess the ability of decision-making and their agility allows for a wide range of communications and networking operations.
REFERENCES
Cognitive radio communications and networks: principles and practice By Alexander M. Wyglinski, Maziar Nekovee, Y. Thomas Houhttp://en.wikipedia.org/wiki/Software-defined_radio