Flexible channel assignment as a method to provide bandwidth in emergency communication

Paper number

IAC-06-B3.P.4.01

Author

Mr. Jin Fei Tang, China Academy of Space Technology (CAST), China

Year

2006

Abstract

Due to its large area and complex topography, China is faced with many kinds of meteorological and geological disasters. On the other hand, most of China’s rural area and mountain area do not have the chance to enjoy the advances of the newest communication technology. So when floods or earthquakes strike these areas, emergency communication will be a big problem. When all other means fail, satellite communication will be the only choice.
China Academy of Space Technology is making its first attempt to develop a geostationary, broadband multimedia multi-beam communication satellite to serve mainland China and regions around. This satellite is very suitable for communication in disaster relief. 
During disaster relief communication period, the communication traffic volume in one or several beams increases very fast. To achieve high performance while keeping satellite cost low, we propose the flexible channel assignment technology in this satellite. This idea is brought from terrestrial wireless communications. In traditional fixed channel assignment (FCA), every beam has a fixed bandwidth, but the bandwidth demand in every beam varies greatly. Frequencies assigned to neighboring beams should satisfy the co-channel interference constraint. In FCA, when bandwidth demand in one beam exceeds the assigned bandwidth, this beam cannot use the bandwidth from other beams, and the call blocking ratio will rise as a result. The idea of flexible channel assignment is to allocate bandwidth in a larger, system scale. The assigned bandwidth of every beam will not be fixed and the regular 4 or 7-color reuse scheme will be rejected. The system makes the decision that best satisfies the bandwidth demand of every beam and the only constraint is the co-channel interference ratio (CIR). In this way, we will achieve higher performance without spending much money in making large bandwidth beams.
Flexible channel assignment is a technique that affects many layers of satellite communication system. Its mathematical model is found to be a complex binary integer programming (BIP) problem. To make the new technology more practical, we investigate its application aspects, such as software, hardware and network support of the flexible channel assignment technology. We employ a neural network algorithm to solve the BIP. To evaluate the performance of the algorithm, we design several scenarios with the Chinese multimedia satellite to run the algorithm and get satisfactory results. Finally we make some remarks on conclusions and future works.

Abstract document

IAC-06-B3.P.4.01.pdf

Manuscript document

IAC-06-B3.P.4.01.pdf (🔒 authorized access only).

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