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Research On Key Technology Of Sensor Selection And Energy Harvesting Based On WBAN

Posted on:2018-09-27Degree:MasterType:Thesis
Country:ChinaCandidate:X L LiuFull Text:PDF
GTID:2348330515978320Subject:Communication and Information System
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Wireless body area network(WBAN)contains many low-power sensors around the human body,which can achieve a variety of applications,such as heath monitoring,entertainment,and medical application,etc..WBAN is required to monitor different physiological parameters with many kinds of sensors in our daily life.And sometimes the physiological parameter needs more than one sensor to monitor the same data for ensuring the accuracy of the sensing data.But the large number of sensors will cause influences on body health and makes people feel uncomfortable,and also some of these sensors are redundant which is a waste of resources.Therefore,sensor selection provides an attractive solution to improve energy efficiency.Recently,some methods are performed to obtain optimal sparse sensor array,such as stochastic control framework,Target tracking channel gain and genetic algorithm,but these algorithms are unavailable for low-power WBAN due to high complexity and computation.So it is necessary and important to perform researches on efficient algorithm which can solve the problem of sparse sensor array synthesis effectively.Those sensors are in small size and have energy-limited batteries,so it is necessary and useful to introduce energy harvesting technology in WBAN.Recently,some researches on energy harvesting circuits,energy harvesting method,and wireless energy and information transfer in wireless networks have been performed,and certainly obtain some achievements.However,there are hardly researches on WBAN under energy harvesting,it is very challengeable because of the characteristics of WBAN,such as the heterogeneity and dynamics of network,low transmission power,etc..So performing further researches on efficient communication algorithm in WBAN based on energy harvesting technology is important and has practical significances.Energy efficiency problem has always restricted the practical applications in WBAN.In this thesis,in order to solve the energy efficiency problem,an optimal sparse sensor array synthesis algorithm and an optimal transmission power allocation algorithm are proposed through performing sensor selection and introduce energy harvesting technology in WBAN.And the wireless energy and information transfer application model in WBAN is proposed,which provides basis for researches on energy harvesting in WBAN.The research approaches are as follows:Firstly,the regular sensor array model is built for those sensors distributed around the human body,and then performing sparse sensor array synthesis via convex optimization to achieve maximizing array sparsity and minimizing the peak of side lobe simultaneously.Then,energy harvesting technology is introduced to WBAN.We propose wireless energy and information transfer application models and indicate the research challenges and opportunities in WBAN under energy harvesting.Finally,an optimal transmission power allocation scheme is proposed to minimize outage probability for point-to-point model in WBAN with energy harvesting.The main contents are as follows:1.Based on sparse linear and planar sensor array synthesis,we indicate the advantages of sparse sensor array synthesis via convex optimization.And then the sensor array models are proposed for sensors distributed around the human body,the head is presented by spherical sensor array,the core body and legs are indicated by different cuboid sensor arrays.2.The sparse spherical and cuboid sensor array is optimized via convex optimization,respectively.And the objective function includes two terms: the weights of array and the peak of side lobe,and the main lobe is restricted in a range of angle.Then we remove the weights of sensors are equal to zero or approximately to zero,so the sparse sensor arrays and their beam patterns are obtained.Finally,the sensor selection problem in WBAN is solved.3.The energy harvesting is introduced to WBAN,and three wireless energy and information transfer application models in WBAN is proposed.We discuss the coexistence problem of wireless energy transfer and information transmission in different application models,and also the research challenges and opportunities are indicated in WBAN with energy harvesting.4.An optimal transmission power allocation scheme is proposed to minimize outage probability for point-to-point model in WBAN with energy harvesting.Then simulations demonstrate that the outage probability is decreasing with the increasing of the harvested energy.In a word,sparse sensor array synthesis has solved the sensor selection problem in WBAN on theory,which provides a potential sensor arranging scheme for building the network framework of WBAN.And researches on wireless energy and information transfer models provide a basis for researches on energy harvesting in WBAN.
Keywords/Search Tags:Wireless body area network, Sparse sensor array synthesis, Wireless energy and information transfer, Convex optimization, Energy harvesting
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