An Overview of Cognitive Radio Network Technology

CRN

1. An Overview of Cognitive Radio Network Technology Presented By:- Nandkishor Joshi

2. Content Introduction Some definitions Spectrum Hole or White Space Concept What is Cognitive Radio Network Issues in wireless communication Spectrum Facts Solution Properties CRN Architecture CRN Functions Cognitive Cycle CRN Applications References

3. Introduction The spectrum is underutilized- Generally, the spectrum is underutilized even in highly populated urban areas. Cognitive Radio is a Technique which is used to efficient spectrum utilization or reduce the spectrum scarcity . According to Federal Communication Commission (FCC), more than 70% of the available spectrum is not utilized optimally

4. Some definitions Primary User (Licensed User) the user which has an exclusive right to a certain spectrum band. In other words, the license holders... No need to be aware of cognitive users No additional functionalities or modifications needed Secondary User (Unlicensed User) Cognitive-radio enabled users Lower priority than PUs

5. Spectrum Hole or White Space Concept Spectrum Hole If the total assigned spectrum is not utilized completely or utilized partially by the primary users that unutilized spectrum is called a spectrum hole or a white space . The cognitive radio identifies these spectrum holes or white spaces and assigns them to the secondary users without causing any interference to the primary users.

6. What is Cognitive Radio Network Wireless communication in which the transmission or reception parameters are changed to communicate efficiently without interfering with licensed users. Parameter changes are based on the active monitoring off several factors in the radio environment (e.g. radio frequency spectrum). This approach is enabled by software‐defined radio frequency spectru m .

7. Issues in wireless communication Going wireless more and more... Lack of interoperability bw. different technologies Lack of spectrum (???)

8. Spectrum Facts Fixed Spectrum Assignment Bandwidth is expensive and good frequencies are take n Recent measurements by the FCC in the US show 70% of the allocated spectrum is not utilized More clever radio Frequency Agility----SPECTRUM SHARING SOLUTION

9. Solution Joseph Mitola 1992 Software Defined Radio(SDR) radio primarily defined in software, which supports a broad range of frequencies, and its initial configurations can be modified for user requirements. Joseph Mitola 1999 Cognitive Radio(CR) SDR + Intelligence SDR : “A radio that includes a transmitter in which the operating parameters of frequency range, modulation type or maximum output power or the circumstances under which the transmitter operates by making a change in software without making any changes to hardware components that also affects the RF emissions . SDR is currently used to build radios that support multiple interface technologies (e.g., CDMA, GSM, and WiFi ) with a single modem by reconfiguring it in software. The concept of cognitive radio was first proposed by Joseph Mitola III in a seminar at KTH (the Royal Institute of Technology in Stockholm) in 1999[1] .

10. Properties Cognitive radio properties Automatic link Establishment( i.e c hannel selection)-: on the Knowledge of primary users’ spectrum usage as a function of location and time Multiple waveform interoperability - Rules of sharing the available resources (time, frequency, space) Qos Measuring/Channel state information gathering -: Embedded intelligence to determine optimal transmission (bandwidth, latency, QoS) based on primary users’ behavior Modification of radio parameter as a function of sensor input Learning about the environment Optimizing with different settings Frequency hoping Software defined Radio properties Reconfigurable Easily Upgradeable Responds to the changes in the operating environment Lower maintenance cost

11. CRN Architecture CRN Architecture

12. CRN Architecture Cont. Architecture Components of a cognitive radio system [3]

13. CRN Functions Spectrum sensing Spectrum mana g e me n t Spectrum mobility Spectrum sharing Spectrum sensing is performed to exploit spectrum holes (opportunities) for unlicensed access. spectrum management is executed to utilize these opportunities without causing interference to the primary user . spectrum mobility allows secondary users to move to another empty frequency band after vacating the current band for the primary user. spectrum sharing allows the secondary user to share the spectrum with the primary user and other secondary users.

14. Cognitive Cycle Cognitive cycle

15. Cognitive Cycle Cont. Cognitive Cycle

16. CRN Applications

17. References [1] J. Mitola III and G. Q. Maguire, “Cognitive radio: making software radios more personal,” IEEE J. personal communications, vol. 6, pp. 13-18, Aug. 1999. [2] J. Mitola III, “Cognitive radio- An integrated agent architecture for software defined radio” Ph.D. dissertation, KTH, Stockholm, 2000. [4] Yao Liu, Peng Ning, Huaiyu Dai, Authenticating Primary Users’ Signals in Cognitive Radio Networks via Integrated Cryptographic and Wireless Link Signatures, 2005. [5]S. Haykin, “Cognitive Radio: Brain-Empowering Wireless Communications,” IEEE Journal on Selected Area in Communication, Vol.23, No.2 February 2005. [6]F.K. Jondral , Software‐defined radio‐basic and evolution to cognitive radio, EURASIP Journal on Wireless Communication and Networking 2005. [3] Bruce Fette , (2006), Cognitive Radio Technology: History and background of Cognitive Radio technologies (pp. 1-6), USA. [7] I. F. Akyildiz , W. Y. Lee, M.C. Vuran and S. Mohanty, " NeXt Generation / Dynamic Spectrum Access / Cognitive Radio Wireless Networks: A Survey,"Computer Networks Journal (Elsevier), Vol. 50, pp. 2127-2159, September 2006. [8] I. F. Akyildiz , W. Y. Lee, M.C. Vuran and S. Mohanty, "A Survey on Spectrum Management in Cognitive Radio Networks," IEEE Communications Magazine, Vol. 46, pp. 40-48, Apr. 2008. [9] M . Sherman, A. N. Mody , R. Martinez, C. Rodriguez, and R. Reddy, “IEEE standards supporting cognitive radio and networks, dynamic spectrum access, and coexistence,” IEEE Communications Magazine, vol. 46, no. 7, pp. 72–79, 2008.

18. Thank you