Implementation of a relay aided D2D communication using software defined radios (SDRS) for cellular networks

Abstract

Device-to-device (D2D) communication is a promising technology that enables direct communication between nearby devices, without the need for intermediate base stations or infrastructure. This technology has the potential to improve the efficiency, reliability, and security of wireless communication networks, and to enable new applications and services. D2D communication can be used in a variety of scenarios, such as in public safety, social networking, mobile gaming, and content distribution. However, in scenarios where direct communication is hindered due to obstacles or long distances, relay-aided D2D communication becomes a crucial solution. This project proposes an innovative relay-aided D2D communication framework designed to overcome these challenges and maximize the potential of D2D technology. The relay nodes act as intermediate devices that assist in forwarding data between D2D pairs, enabling communication over longer distances. By leveraging the relay nodes strategically placed within the network, the proposed system aims to overcome the limitations of direct D2D links and enhance overall system throughput. In this project, we prototyped the 4G LTE wireless communication standard over the software defined radio (SDR) technology in particular bladeRF x40 as the radio frequency (RF) hardware frontend, SRSRAN as the open-source LTE software complaint with Linux based application particularly Ubuntu version 20.04 for our case running on core i5 laptops. The srsRAN offers an open-source implementation of all LTE components such as the user equipment (UE), evolved base station (eNB) and evolved packet core (EPC). We used two laptops to setup the 4G network with one laptop serving as the user equipment (srsue) and on the second laptop was running both the srsepc and srsenb at the same time. We were in position to setup the 4G network and it was running but due to various environment factors that hinder signal transmission, interference from other networks using the same spectrum with our setup couldn’t enable stable communication between our UE and the core network. This hindered us from achieving the main objective of our project. For future implementation of this work, I recommend setting up this network testbed in an enclosed environment with minimal external network interference in case of wireless communication as a mode of signal transmission, collaborating with existing network companies in the country to be able to use shared spectrum and also opting for cabled connection between the core network and UE to bypass the interferences from the environmental factors like noise as well as other external cellular networks. Using writable Sim cards that can be configured with our network parameters to be able to have a complete network setup.