In order to handle the huge amounts of data transmitted through hot spots and to increase cell coverage in buildings, this paper proposes a sectored cellular network with small cells (SCNSC) embedded in each sector. T...In order to handle the huge amounts of data transmitted through hot spots and to increase cell coverage in buildings, this paper proposes a sectored cellular network with small cells (SCNSC) embedded in each sector. Two region types, sectors and variable-radius small cells are classified in an SCNSC macro cell. Because the system capacity is enhanced by using fractional frequency reuse (FFR), the overall channel bandwidth is divided into two or three frequency bands depending on whether the number of sectors in a macro cell is even or odd. For the purpose of topological evaluation on the proposed SCNSC, we build an analytical model using Markov chain theory. The performance measures include new-call blocking and handoff-call dropping probabilities, average waiting times, and normalized throughputs in each sector and its embedded small cell by varying mobile stations’ moving speeds, the number of sectors, and the radius size of an embedded small cell. From the evaluation results, it is demonstrated that adjusting either the number of sectors or the coverage of an embedded cell can satisfy different service demands.展开更多
Two amphibian species,Megophrys daweimontisandAmolops vitreus,are recorded for the ifrst time from Vietnam, on the basis of a new amphibian collection from Dien Bien and Son La provinces. In addition, acoustic analysi...Two amphibian species,Megophrys daweimontisandAmolops vitreus,are recorded for the ifrst time from Vietnam, on the basis of a new amphibian collection from Dien Bien and Son La provinces. In addition, acoustic analysis ofA. vitreus is also provided based on the advertisement calls recorded in Muong Nhe Nature Reserve of Dien Bien Province, Vietnam.展开更多
文摘In order to handle the huge amounts of data transmitted through hot spots and to increase cell coverage in buildings, this paper proposes a sectored cellular network with small cells (SCNSC) embedded in each sector. Two region types, sectors and variable-radius small cells are classified in an SCNSC macro cell. Because the system capacity is enhanced by using fractional frequency reuse (FFR), the overall channel bandwidth is divided into two or three frequency bands depending on whether the number of sectors in a macro cell is even or odd. For the purpose of topological evaluation on the proposed SCNSC, we build an analytical model using Markov chain theory. The performance measures include new-call blocking and handoff-call dropping probabilities, average waiting times, and normalized throughputs in each sector and its embedded small cell by varying mobile stations’ moving speeds, the number of sectors, and the radius size of an embedded small cell. From the evaluation results, it is demonstrated that adjusting either the number of sectors or the coverage of an embedded cell can satisfy different service demands.
基金supported by the Hanoi National University of Education (Small Grant No. SPHN-13-247)Field work and equipment was partially supported by the Idea Wild to D.T. LE and A.V. PHAM+1 种基金Research of T.Q. NGUYEN in northwestern Vietnam is funded by the National Geographic Society (Grant No. 9492-14)the Alexander von Humboldt Foundation (VIE 114344)
文摘Two amphibian species,Megophrys daweimontisandAmolops vitreus,are recorded for the ifrst time from Vietnam, on the basis of a new amphibian collection from Dien Bien and Son La provinces. In addition, acoustic analysis ofA. vitreus is also provided based on the advertisement calls recorded in Muong Nhe Nature Reserve of Dien Bien Province, Vietnam.
