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Optimal and water-Filling Algorithm approach for power Allocation in OFDM Based Cognitive Radio System
| Content Provider | Semantic Scholar |
|---|---|
| Author | Patil, Deepak Y. Bawada, Kasba |
| Copyright Year | 2017 |
| Abstract | Technology plays vital role in today’s world. Growing technology in wireless communication and demand for spectrum is growing day by day. Many applications in wireless are sharing same medium and due to strain which leads to lack of spectrum in given limited band. As per the report published by (FCC) Federal Communication Commission the spectrum band are not utilized efficiently where as some of spectrum bands are used heavily. The potential solution for this problem is to allocate the spectrum dynamically through means of cognitive radio. In this paper water-filling and optimal power allocation algorithm has been investigated in simulation environment. Present numerical result show that optimal power allocation algorithm can achieve higher transmission compare to water-filling (i.e. classical) power allocation algorithm. The above algorithm is compared to total transmission power, interference and individual peak constraints. KeywordsCognitive Radio, Primary user, secondary user Orthogonal frequency division multiplexing. Introduction With the advance development in wireless communications, frequency spectrum has becoming a valuable natural resource, and limitation of the spectrum is a serious issue. On other hand Federal Communication Commissions (FCC) has reported the underutilization of electromagnetic radio spectrum [1]. In some cases, the spectrum band is underutilized by licensed users (primary user) and unlicensed users (secondary user) are not allowed to operate in licensed spectrum bands. This leads to unbalanced spectrum utilization. Spectral efficiency can be increased significantly by giving access of the frequency bands to a group of unlicensed users (referred to as secondary or CR users). Cognitive radio(CR) system is unique softer-ware defined radio proposed to improve spectrum efficiency by exploiting unused spectrum in dynamically changing environments. The cognitive radio is an innovative system design which involves smartly sensing the holes of spectrum and then determining the transmission characteristics with respective to symbol rate, power, bandwidth, latency etc. of a group of secondary users based on the nature of the users to whom the spectrum has been licensed (referred to as primary users). A Cognitive radio (CR) network is a technology in which a frequency band used by one or multiple primary users in a primary network can be operated by a secondary user’s network which consists of one or multiple secondary users. To guaranty the quality of service (QoS) of the Primary User (PU) and to maximize the transmission rate of the secondary users is one of the most crucial roles for a Cognitive radio system [1]. Orthogonal frequency division multiplexing (OFDM) is a promising tech for cognitive radio systems. With OFDM, the SU has the ability to smoothly flexible fill the spectral gaps left unused by PUs. It also can determine its location; sense spectrums of other devices, and change in frequency, adjust output power and even alter transmission parameters and characteristics. It can fulfill the SUs communication needs without altering the FCC rules. Cognitive radio mainly works on three tasks including: Radio scene analysis in which CR can detect spectrum holes, lightly used band, interference and Channel state estimation, in which CR determine the channel capacity and the state of the channel; Spectrum management, in which CR make the spectrum sharing efficient. The CR design is an featuring new methods of radio design philosophy which involves smoothly sensing the vacant spectrum and then determining the transmission characteristics (e.g., symbol rate, power, bandwidth, latency) of a group of secondary users based on the behavior of the users to whom the spectrum has been licensed (referred to as primary users). Although opportunistic spectrum access would allow CR user to discover and access available spectrum International Journal of Engineering Research and Technology. ISSN 0974-3154 Volume 10, Number 1 (2017) © International Research Publication House http://www.irphouse.com |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.ripublication.com/irph/ijert_spl17/ijertv10n1spl_90.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
