Selman Kulaç

Effective cooperative spectrum sensing in IEEE 802.22 standard with time diversity

IEEE is developing a wireless communication standard that will take place in cognitive radio class and be valid in the world. Data communication capability supporting is aimed with this standard called IEEE 802.22 to the rural area users in TV bands. In the TV bands, not to cause harmful interference to the existing TV receivers and to communicate in unused channels, effective detection of unused channels is needed. This is succeeded with effective spectrum sensing. Sensing the presence of TV signals in the channel being tracked is more possible with using effective spectrum sensing techniques. In this paper, it is demonstrated with detailed simulations that a base station and users in an IEEE 802.22 cell sense TV signals better with setting up cooperation and it is reached to the better performance results by adding time diversity to this cooperation. Besides, it is also presented in this paper that effective cooperation is done with decrease of cost, power consumption and complexity by choosing relays who have higher SNR threshold.

Security Belt for Wireless Implantable Medical Devices

In this study, a new protective design compatible with existing non-secure systems was proposed, since it is focused on the secure communication of wireless IMD systems in all transmissions. This new protector is an external wearable device and appears to be a belt fitted around for the patients IMD implanted. However, in order to provide effective full duplex transmissions and physical layer security, some sophisticated transceiver antennas have been placed on the belt. In this approach, beam-focused multi-antennas in optimal positions on the belt are randomly switched when transmissions to the IMD are performed and multi-jammer switching with MRC combining or majority-rule based receiving techniques are applied when transmissions from the IMD are carried out. This approach can also reduce the power consumption of the IMDs and contribute to the prolongation of the IMD’s battery life.

Secure transmission of commands using multicarrier structure for wireless implantable medical devices

Wireless communication has growing interests in health care domain, especially in implantable medical devices (IMD). Because of the open nature of the wireless signals, providing a secure communication between IMD and physician device becomes a significant concern. In this study, we propose a security mechanism against eavesdroppers to protect the data sent by a physician. The importance of keeping these data in safe stems from the fact that the data consists of commands and remote control information which are vital for the patients. In the proposed method, secure transmission of command data by embedding and hiding data in multicarrier structure and less complex reception for IMD with customized frequency dehopping technique is employed. As indicated in performance evaluations, even with super computers, an eavesdropper can not decode the protected data in tremendous amount of time (years).

ID identification by using face detection and recognition systems

In recent years, significant achievements have been achieved in the field of face recognition. Face recognition are special pattern recognition which are used in banking for identity approving and the entrance of controlled areas, the places where the security control impending to airports, to control machines, to follow-up of persons. In this study, face recognition applications on the Yale face databases have been performed by using PCA (Principal Component Analysis), LDA (Linear Discriminant Analysis), LBP (Local Binary Patterns). Database consist of right-light, center-light, left-right, no glasses, glasses, normal, wink, sleepy, surprised, happy, sad images. In the face recognition pre-processing steps, HE (Histogram Equalization), HE+ Median Filter, HE+Gaussian filter, He+Laplace Filter was used. It is provided to select the appropriate method from the system depending on state of image. Thus the system recognition rate increases of up to 6% was observed. Application was developed by using Microsoft Visual Studio 2010 C #. EMGU CV library for image processing algorithms and SQL Server 2008 Express for database processing were used.

Cooperative spectrum sensing in IEEE 802.22 standard

IEEE is developing a wireless communication standard that will take place in cognitive radio class and be valid in the world. Data communication capability supporting is aimed with this standard called IEEE 802.22 to the rural area users in TV bands. In the TV bands, not to cause harmful interference to the existing TV receivers and to communicate in unused channels, effective detection of unused channels is needed. This is succeeded with effective spectrum sensing. Understanding of presence of TV signal in channel tracked is more possible with that reason. In this paper, it is demonstrated with detailed simulations that a base station and users in an IEEE 802.22 cell sense TV signals better with setting up cooperation and it is reached to the better performance result with adding time diversity to this cooperation.