A Software Defined Radio Platform for Decode and Forward Relay Nodes Implementation

Relay Nodes (RNs) are being currently studied as a solution for mobile communications in scenarios where the propagation conditions are challenging. This could include high-mobility scenarios, low coverage areas or outdoor to indoor situations. Several types of Relay Nodes are proposed in the literature and by standardization organizations such as 3GPP. The use of commercial low-cost Software Defined Radio (SDR) can contribute to a reduction of the development time and allow the testing of new algorithms and specification solutions for LTE/LTE-A and 5G scenarios. In this paper, a proof of concept of an LTE Decode-and-Forward (D&F) Relay Node using SDR is presented. The developed SDR platform implements LTE Physical Layer (PHY), Medium Access Control Layer (MAC) and some Radio Link Control (RLC) features, using two NI-USRP-2901. The objective is to evaluate the viability of implementing Decode-and-Forward RNs using SDR, their performance according to 3GPP standards and the resulting improvement on the user’s throughput.