Network Performance Evaluation of Abis Interface over DVB-S2 in the GSM over Satellite Network

This paper deals with establishing a GSM link over Satellite. Abis interface, which is defined between Base Transceiver Station (BTS) and Base Station Controller (BSC), in a GSM network is considered here to be routed over the Satellite. The satellite link enables a quick and cost-effective GSM link in meagerly populated areas. A different scenario comparison was done to understand the impact of Satellite environment on network availability comparing to terrestrial scenario. We have implemented an Abis interface over DVB S2 in NS2 and evaluated the performance over the high delay and loss satellite channel. Network performance was evaluated with respect to Satellite channel delay and DVB S2 encapsulation efficiency under different amount of user traffic and compared with the terrestrial scenario. The results clearly showed an increased amount of SDCCH and TCH channels required in the case of satellite scenario for the same amount of traffic in comparison to conventional terrestrial scenario. We have optimized the parameters based on the simulation results. Link budget estimation considering DVB-S2 platform was done to find satellite bandwidth and cost requirements for different network setups. 1. Introduction The success story of second-generation (2G) terrestrial mobile systems (GSM) and the relative demise of 2G mobile satellite systems (MSS) such as, Iridium and Globalstar have influenced the future of MSS. These two distinct but interrelated events demonstrate the importance of proper market and business strategies for the success of the future mobile satellite industry. Global System for Mobile communications (GSM) is the most popular means for voice and data communication having more than 2 billion subscribers all over the world. Still 3/4 of the globe is not covered by GSM networks. Despite growing demand for GSM services in rural areas, it is not cost-effective for GSM service providers to cover areas with meager population density. Poor terrestrial infrastructure in remote areas leads to high capital expenditures for establishing new links by means of fiber optic cables or microwave links, leading to an alternate and cost-effective solution like Satellite interface. Proposed work considers DVB-S2 [1] as a physical interface between Earth station and Satellite due to its highly spectrum efficient Modulation and powerful FEC schemes (ModCode). DVB-S2 has two different frames, long (64800？bit) and short (16200？bit) frames. Hence encapsulation efficiency and Network bandwidth utilization should be evaluated for different scenarios. Presently there