Software Defined Radio implementation of DS-CDMA in inter-satellite communications for small satellites

In this paper, we study the problem of multi-user inter-satellite communications in a network of small satellites and design and implement of an optimum CDMA-based multiple access communication using Software Defined Radios. Inter-satellite links (ISL) enable small satellites to exchange information and share resources while reducing the traffic load to the ground. The ISL assist in performing advanced functions including distributed processing and autonomous applications. By utilizing the ISL in maintaining the relative distance between the satellites, navigation, and positioning accuracy is improved greatly. The ideology proposed here is to implement remote modifications in inter-satellite communication after launch using Software Defined Radios (SDRs), while accommodating an adaptive autonomous small satellite network. Remote upgrades from the ground as well as the potential to accommodate new applications and future services without hardware changes is very promising. Software defined radio-based implementation of an ISL can assist in enabling an adaptive and reconfigurable communication system, which can achieve higher data rates and modification of frequencies. In this paper, we designed and implemented a multi-user inter-satellite communication network using SDRs, where Code Division Multiple Access (CDMA) technique is utilized to manage the multiple access to shared communication channel among the satellites. This research is the first work to study and implement the utilization of SDRs for inter-satellite communications in small satellite systems.