Physical-layer Performance Evaluation of a High-performance LAN- LAN Interconnection via Satellite

Abstract

With the proliferation of computer networks comes the need for better internetworking techniques for more efficient communication. A Ka-band satellite link between two high- performance local-area networks (LANs) is described. the LANs are assumed to use the High-performance Parallel Interface (HIPPI), which is a parallel point-to-point interface affording data rate near 1 Gbit/s. In order to maintain the parallel structure, the data lines share the satellite channel by code- division multiple access (CDMA). Two CDMA coding schemes are examined, namely Gold codes and Barker codes. Since HIPPI is a synchronous system, a modification to each of the CDMA codes is described to improve performance. For each of the CDMA codes, two modulation schemes, multiple-amplitude minimum-shift-keying (MAMSK) and continuous- phase frequency-shift-keying (CPFSK) are modeled. In order to obtain acceptable bit-error-rate (BER) performance, equalization of the channel to compensate for the satellite nonlinearities is described. The satellite channel is simulated for each of the four possibilities of CDMA code and modulation scheme in order to predict BER performance. It is found that MAMSK outperforms CPFSK for a low signal-to-noise ratio, but CPFSK outperforms MAMSK for a high signal-to-noise ratio.