PROJECT PRESENTATIONON

Spectrum sensing in cognitive radio using Energy detection technique

-P.PANEENDRA BABU

-T.SAI CHARAN

-A.SAINATH

COGNITIVE RADIO

OVERVIEW OF PROJECT:•WHAT IS COGNITIVE RADIO?•WHY COGNITIVE RADIO?•TYPES OF COGNITIVE RADIO•COGNITIVE CYCLE•4 MAIN FUNCTIONS•ONE OF THE FUNCTIONS:SPECTRUM SENSING•SPECTRUM SENSING TECHNIQUES:•ONE OF THE SPECTRUM SENSING TECHNIQUES: TRANSMITTER DETECTOR:

• ENERGY DETECTOR TECHNIQUE:• MATLAB PROGRAM

•APPLICATIONS AND ADVANTAGES

WHAT IS COGNITIVE RADIO? Cognitive radio is an intelligent wireless communication system that can sense the changing environmental conditions and can change their parameter like frequency, modulation techniques, coding techniques, power etc.

WHY COGNITIVE RADIO?• Recent measurements by Federal Communications Commission (FCC) have shown that 70% of the allocated spectrum in US is not utilized.

• Based on fixed spectrum allocation methodology, in many countries, most of the available radio spectrum has been assigned for various services

•The reasons for the under utilization of the spectrum are

WHY COGNITIVE RADIO?•This motivates the concept of spectrum reuse that allows secondary users/network to utilize the radio spectrum licensed/allocated to the primary users/network when the spectrum is temporally not being utilized.

•The core technology behind spectrum reuse is Cognitive Radio•Spectrum holes are detected and used.

Types of Cognitive Radio:•BASED ON TYPE OF APPROACHES: Full cognitive radio (“Mitola Radio”):Every possible

parameter taken into account.Spectrum sensing cognitive radio: Only radio frequency

spectrum Considered.•BASED ON FREQUENCY SPECTRUM: LICENSED BAND COGNITIVE RADIO UNLICENSED BAND COGNITIVE RADIO

COGNITIVE CYCLE:

4 main steps:•SPECTRUM SENSING : To detect the unused spectrum and sharing it without harmful interference with other users.

•SPECTRUM MANAGEMENT : The task of capturing the best available spectrum to meet user communication requirements.

•SPECTRUM MOBILITY : As the process where the cognitive user exchanges its frequency of operation.

•SPECTRUM SHARING : To providing a fair spectrum scheduling method among the users.

SPECTRUM SENSING The process of determining the free (unused) spectrum of the primary user without making any interference and disturbing the rights of licensed user is called as spectrum sensing•It refers to detect the unused spectrum holes. •POTENTIALLY UNUSED BANDS. •Detecting primary users is the most efficient way to detect spectrum holes.

SPECTRUM HOLES

SPECTRUM SENSING TECHNIQUES

Transmitter detector technique It has been seen that each transmitter detection technique has a Signal to Noise Ratio (SNR) threshold, below which these techniques fail to work robustly

• MATCHED FILTER DETECTION• ENERGY DETECTION• CYCLOSTATIONARY DETECTION

GENERAL MODEL:

Two probabilities are of interest for spectrum sensing: probability of detection, which defines, under hypothesis H1, the probability of the algorithm correctly detecting the presence of primary signal; and probability of false alarm, which defines, under hypothesis H0, the probability of the algorithm falsely declaring the presence of primary signal.y(n) = s(n) + u(n)----------H1y(n) = u(n)-----------------H0

ENERGY DETECTION TECHNIQUE:•The energy detector cannot differentiate signal types but can only determine the presence of the signal. Thus, the energy detector is prone to false detection triggered by unintended signals.

•When the receiver cannot gather sufficient information about the PU signal, for instance, if the power of the random Gaussian noise is only known at the receiver, the optimal detector is the energy detector.

•Intuitively, if the signal is present, the energy of the received data increases

FLOW CHART FOR PROGRAM:

Receiver operating characteristics:

As expected, as Y’ increases, Pfa and Pd decrease; the inverse is also true. This type of performance description is called the Receiver Operating Characteristic (ROC)

SNR=-10DB

SNR=-20DB

END OF ENERGY DETECTION TECHNIQUE

ADVANTAGES:•Increases Spectrum efficiency.

•Unused Spectrum used for new business proposition.

•Increases data rate by using good channels and rejecting bad ones.

APPLICATIONS:• Cellular technology.

• Military application.

• Proper use of unused Spectrum.

•Proposed 5G technology.

•EMERGENCY NETWORK.(WHEN WEATHER CONDITIONS ARE NOT GOOD)