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RISS 인기검색어
- 검색키워드
- 저자 : Nomoto Shinichi (검색결과 4 건)
- 무료
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- 유료
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Study on Scheduling Algorithm for High-Power Short Message Delivery via Multiple Non-GSO Satellites
Nomoto, Shinichi,Shibuya, Megumi,Konishi, Satoshi 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-
Global short message delivery services via satellites are considered attractive if the service can be supported to indoor subscribers. In order to establish the communications link, it is required to concentrate high transmission power into a spotbeam even by a Non-GSO satellite system with low Earth orbits. The idea can be realized by a kind of TDMA scheme where only a single spotbeam per satellite is fired at a timeslot in an efficiently scheduled manner. The paper proposes a scheduling algorithm that enables each satellite to concentrate its power into a spotbeam illuminating an addressed area at a prescribed timeslot, while causing no interference with other spotbeams from adjacent satellites, so that a subscriber in the area can easily establish the synchronization and efficiently receive a message addressed to him or her. Some numerical evaluations are given for a 6-hour period MEO system, for example, to demonstrate the effectiveness and performances.
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Optimum Traffic Distribution Algorithm for Satellite System Taking Account of Satellite Power Limit
Nanba, Shinobu,Konishi, Satoshi,Nomoto, Shinichi 통신위성우주산업연구회 2000 Joint Conference on Satellite Communications Vol.2000 No.-
In satellite communications systems, satellite transmitting power (in short, 'satellite power') is one of the critical radio resources for satellite systems, as well as spectrum resources, due to the limited ability of onboard electric generator. Therefore, for attaining optimum satellite radio resource utilization, it is not enough to just consider the spectrum resources but also to take account of the satellite power. In multiple satellites systems, the coverage of a satellite has overlapping areas with those of adjacent satellites. In this case, the traffic demand in overlapping area can be accommodated by either of visible satellites. For these systems, this paper proposes an algorithm to provide an optimum traffic distribution among satellites. The algorithm adopts linear programming model considering satellite power limits. Numerical examples demonstrate that the proposed algorithms contribute to maximizing the system capacity.
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Nanba, Shinobu,Konishi, Satoshi,Nomoto, Shinichi 통신위성우주산업연구회 2002 Joint Conference on Satellite Communications Vol.2002 No.-
In wide-area wireless access systems with a large number of cells such as satellite systems and HAPS (High Altitude Platform Systems), a Radio channel allocation scheme based on a pre-plan, where a number of channels are allocated to each cell beforehand, is considered to be effective to reuse the radio resources. In such a channel allocation, it is a problem that the number of channels to be allocated to cells can not be determined appropriately in case of multiple services with different QoS parameters. In this paper, a radio channel allocation scheme based on a pre-plan for multiple services is proposed. The scheme attempts to allocate channels to each cell for all services while keeping fairness among services by introducing a degree of satisfaction as a common measure between services. The degree of satisfaction for each service can be defined by a satisfaction function, which is given for every service. In addition, we device an algorithm to realize the scheme. Moreover, other two algorithms are introduces to achieve fairness among services, where available resources are exclusively partitioned among services by a traffic ratio among services or keeping DoS among services constant and then a number of channels are allocated to each cell according to the traffic demands ratio between cells. In our simulation, these algorithms are compared and evaluated.
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Konishi, Satoshi,Kishi, Yoji,Nanba, Shinobu,Nomoto, Shinichi 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-
In wide-area wireless access systems such as satellite communications systems and stratospheric platform systems, electric power supply for radio communications is realized by using solar photovoltaic cells and/or fuel cells. Hence, not only frequency band but also electric power is a limited and crucial radio resources for those systems. Although radio channel allocation algorithms taking account of the frequency constraint only or the power constraint only have been proposed, radio channel allocation algorithms taking account of the both constraints simultaneously have not been studied enough so far. This paper proposes a radio channel allocation algorithm utilizing the linear programming method to address this issue. The proposed algorithm firstly allocates radio channels in proportion to the traffic demand distributed over the area and then maximizes the total radio channels allocated to systems. Some numerical results are given for a stratospheric platform system that covers a part of Japanese land, for example, in order to demonstrate the effectiveness of this algorithm.
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