Development of a database-assisted spectrum access scheme for cognitive radio (CR) utilizing radar bands (2-4 GHZ) /
Wireless communication systems have developed very rapidly in the past few decades. This expansive development has diminished the spectrum availability and caused spectrum scarcity. Cognitive radio idea was introduced to utilize the spectrum efficiently. However, occupancy of spectrum bands varies...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2017
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| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
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| LEADER | 050730000a22002890004500 | ||
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| 008 | 170428s2017 my a f m 000 0 eng d | ||
| 040 | |a UIAM |b eng |e rda | ||
| 041 | |a eng | ||
| 043 | |a a-my--- | ||
| 050 | 0 | 0 | |a TK5103.4815 |
| 100 | 1 | |a Mohamoud, Mohamoud Ali, |e author | |
| 245 | 1 | |a Development of a database-assisted spectrum access scheme for cognitive radio (CR) utilizing radar bands (2-4 GHZ) / |c by Mohamoud Ali Mohamoud | |
| 264 | 1 | |a Kuala Lumpur : |b Kulliyyah of Engineering, International Islamic University Malaysia, |c 2017 | |
| 300 | |a xii, 90 leaves : |b illustrations ; |c 30cm. | ||
| 336 | |2 rdacontent |a text | ||
| 502 | |a Thesis (MSCE)--International Islamic University Malaysia, 2017. | ||
| 504 | |a Includes bibliographical references (leaves 87-89). | ||
| 520 | |a Wireless communication systems have developed very rapidly in the past few decades. This expansive development has diminished the spectrum availability and caused spectrum scarcity. Cognitive radio idea was introduced to utilize the spectrum efficiently. However, occupancy of spectrum bands varies from one band to another. Radio frequency measurements pointed that radar bands (2- 6GHZ) occupancy is very low, usually under 5%, and static throughout a day period. This dissertation develops a spectrum access technique which utilizes both spatial and temporal spectrum opportunities. This technique combines energy detector based sensing scheme and dynamic frequency selection with database scheme. The proposed method's performance is then analyzed and compared with each technique separately. The proposed schemes have been mathematically modeled and their simulation is implemented using MATLAB. Energy detection technique is based on detecting signals received from primary systems and comparing it with a threshold to decide the availability of the target spectrum band while dynamic frequency selection determines the spectrum holes by gathering aggregate interference from secondary systems and evaluating whether that aggregate interference degrades the performance of the primary system or not. In the analysis of energy detector performance, it was found that, better detection performance is achieved with higher SNR values. Energy detection performance was investigated under the influence of AWGN, Rayleigh and Nakagami fading. A 10 dB SNR level was taken to show the difference in detection performance under these three channels. To attain a target detection probability of 0.90 for AWGN, Rayleigh and Nakagami fading, false alarm probability is estimated at 0.008, 0.004 and 0.034 respectively. Thus, the detection performance is higher in Nakagami channel in comparison with Rayleigh channel as the fading severity is higher in Rayleigh channel. Furthermore, in examining the protection region with and without database information. It was discovered that, the protection region significantly decreases when the secondary user has information about the radar rotation as well as radar antenna pattern. For example, in Figure 4.11, when the information about radar rotation and antenna pattern is not provided by the database, the protection regions are 1403 km, 437 km and 239 km for radar blind user, main/side lobe interferer and optimal distance cases respectively. In comparison, when the information from the database about radar rotation and antenna pattern is used the protection region reduces quite significantly, it goes down to 50 km,18 Km and 10 Km for radar blind user, main/side lobe interferer and optimal distance cases respectively. This is because, when secondary user has no information about radar rotation, it has to assume a constant maximum gain; therefore, the separation distance will be constant. On the other hand, when information about radar rotation is utilized, the radar gain will vary accordingly. Similarly, the throughput improves with the information about radar rotation and its antenna pattern. Though the objectives of this dissertation has been achieved there were some limitations. First, the accuracy of information provided by database has not been discussed, also the cases where the connection to data base is lost has not been considered. Moreover, a comprehensive study on Wi-Fi performances has not been done. | ||
| 596 | |a 1 | ||
| 655 | 7 | |a Theses, IIUM local | |
| 690 | |a Dissertations, Academic |x Department of Electrical and Computer Engineering |z IIUM | ||
| 710 | 2 | |a International Islamic University Malaysia. |b Department of Electrical and Computer Engineering | |
| 856 | 4 | |u http://studentrepo.iium.edu.my/handle/123456789/4546 |z Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. | |
| 900 | |a sbh-aaz-ls-naw | ||
| 999 | |c 436089 |d 470017 | ||
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