According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probabi...According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probability,by means of theoretical analysis and computation.The result shows that the probability of wireless collision increases linearly with an increase in the number of tags.The probability of collision and leak reading can be reduced by extending the working period of the duty cycle and using a backoff algorithm.In a practical application,a working schedule for available labels has been designed according to the requirement of the project.展开更多
In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wy...In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.展开更多
基金Supported by the National Natural Science Foundation of China(71401061)the Education Department of Shandong Province Science and Technology Plan Project(J07WH03)
基金supported by the Fund of Coal Gas Sensing Technology and Early Warning Systems-Based Theory and Key Technology Research (No.50534050)
文摘According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probability,by means of theoretical analysis and computation.The result shows that the probability of wireless collision increases linearly with an increase in the number of tags.The probability of collision and leak reading can be reduced by extending the working period of the duty cycle and using a backoff algorithm.In a practical application,a working schedule for available labels has been designed according to the requirement of the project.
基金supported in part by the National Natural Science Foundation of China under Grant No. 61072059
文摘In this letter, the physical layer security of hybrid automatic repeat request with chase combining(HARQ-CC) scheme is investigated from the viewpoint of information theory. Different from the literature which used Wyner code, our analysis focuses on the general scenario without specific code. We firstly obtain the outage probability of both main channel and wiretap channel. Since retransmissions are completely determined by main channel, we then prove that its achievable diversity order equals to maximum transmission number() while this order of wiretap channel is only one. Furthermore, we evaluate the metric of secure gap which demonstrates the difference between main channel and wiretap channel with reliable and secure constraints. As increases, the secure gap decreases monotonously. When is large enough, the security can be guaranteed even if wiretap channel is better than main channel.
