Using low Earth orbit satellite system and DS-CDMA scheme for mobile voice and data communication

Abstract

In this paper we propose a low earth orbiting (LEO) satellite system that implements a direct sequence code division multiple access (DS-CDMA) scheme to provide increased coverage and greater system capacity. All system design aspects are described, including system antennas, modulation, frequency allocation, satellite network altitude, and datdvoice transmission speeds. This is then followed by capacity calculations and link budget analysis. The capacity and performance analysis of the proposed system shows that it is capable of providing high quality links with BER of 1'0-4 at a maximum capacity that exceeds three times the processing gain achievable by the spreading codes. The budget links analysis shows that a transmitted signal power of -3.936 dB is required by the mobile transmitter to maintain an uplink energy to interference ratio EdIo = 25.34 dB while a required satellite EIRP of only 10.75 dB is needed to maintain a downlink energy to interference ratio E& = 16.34 dB.