The simulation of advanced network protocols for wide area diversity Ka-band VSATs

This paper presents the results of a comprehensive simulation study in which the use of spatial diversity techniques is investigated as a means of overcoming the propagation impairments that affect radio communication via satellite - particularly at Ka band. Such impairments are typically due to rainfall which is usually quite limited in geographical extent. By distributing a small array of Ka band VSAT terminals around a city centre and interconnecting them via Metropolitan Area Network it has been shown that significant improvements in the performance, reliability and availability of the service can be achieved. Each VSAT is connected to the MAN via a conventional network router. When a particular VSAT is adversely affected by propagation impairments it is able to offload some or all of its traffic to another VSAT. A central Wide Area Diversity Controller is used to assess VSAT link performance and allocate an appropriate VSAT to carry the traffic. Such link reallocation can be handled transparently to the end users