Spectrum Sensing Based On Energy Detection In Mobile Scenario

In order to better solve the problem of shortage of spectrum resources.Cognitive radio is proposed by transmitting cognitive user data without interferingwith the primary users in the case of spectrum resource are not fully used byauthorized primary users. The spectrum sensing technology is supposed toaccurately and efficiently sense spectrum band to determine whether the primaryuser exists or not as the first and important step in cognitive radio. Traditionalcognitive Radio spectrum sensing algorithm assumes that the network structure isstatic. Since IEEE802.22makes an amendment for wireless local area network byusing mobile portable devices. Cognitive radio network topology changesdynamically, cognitive users may be out of the primary user protection range, andexperienced mobile channel conditions which is always changed. As thetraditional spectrum sensing algorithm is based on a static topology, it is notsuitable for dynamic cognitive radio networks.Firstly, the traditional spectrum sensing algorithm based on a static model istheoretically analysed and verified by MATALB simulation. By comparison ofthree single-node spectrum sensing: Cyclostationary feature detection, matchedfilter, energy detector, we have such conclusion that energy detector is best forlocal spectrum sensing algorithm in a dynamic model, because cognitive users doneed the prior knowledge of the primary user signal and complicated mathematicalcomputation and it could be widely applied. Cooperative sensing algorithm canbe a good solution for terminal hidden problem and communication channelvarying a lot to improve detection performance. For several combination criteriain cooperative sensing linear weighting method can get better performance.In cognitive dynamic network structure, the mobile user can be divided intotwo cases: mobile primary users and mobile cognitive users. The former is focusedon studying the impact of mobile primary user. Cognitive users can be out ofprimary user protection range for the mobile primary user. This can be a factor forthe primary user signal detection. We define a new expessrion for spectrumsensing in mobile scenario. It is conluded that detection ability can make adifference in primary signal spectrum sensing. Then detection ability in randomwalk model and random waypoint model for one-dimensional and two-dimensional. The analysis are verified by MATLAB simulation results.The latter is focused on the detection performance of spectrum sensing withcognitive users within the protection range. Mobile cognitive radio users are experienced different channel conditions and shadow fading, and suffered attacksby malicious users. The reliability of the user’s location and reliability of reportsare combined as trust value. If the sum of trust values in sliding window exceedsthe trust threshold, the data is excluded. It turns out that the improved cooperativespectrum sensing algorithm can increase primary signal detection performance inmobile cognive users.