[Paper Review] LTE Standard-Compliant D2D Communication: Software-defined Radio Implementation and Evaluation

S. C. Jain, Yi Zhang+1 more|arXiv (Cornell University)|Apr 29, 2019

Advanced MIMO Systems Optimization4 references4 citations

TL;DR

This paper presents the first software-defined radio (SDR) implementation of LTE Release 12-compliant Device-to-Device (D2D) communication, including sidelink, relay, and dynamic mode selection. Built on the open-source srsLTE platform using USRP hardware, it enables real-time control of radio parameters via GUIs and demonstrates cell range extension through D2D relaying with measurable SNR, throughput, and BLER performance metrics.

ABSTRACT

In this paper, we describe the design and implementation of D2D communication functionality for LTE. To our knowledge, this is the first such implementation that is compliant with the LTE Release 12 standard. In this paper, we design and demonstrate an experiment on mode selection between infrastructure mode and D2D communication mode in LTE networks. We implement our system on a software-defined radio SDR testbed, augmenting the open-source LTE eNodeB and UE implementation provided by the srsLTE software suite. Our measurements demonstrate the cell extension capabilities of D2D and quantify the SNR and throughput obtained by a subscriber when directly served by the eNodeB and when provided connectivity through the relay UE. Our implementation of sidelink, relaying, and mode selection functionality enables experimentation and prototyping of D2D communication that can assist in standardization, research, and development.

Motivation & Objective

• To develop the first SDR-based, LTE Release 12-compliant sidelink physical layer implementation for D2D communication.
• To extend the srsLTE open-source platform with full sidelink, relay, and dynamic mode selection functionality.
• To enable real-time experimentation and parameter control via GUIs for eNodeB, relay UE, and remote UE.
• To evaluate the performance of D2D relaying in terms of SNR, throughput, and BLER for cell coverage extension.
• To support standardization, research, and development of D2D and proximity services in LTE and 5G networks.

Proposed method

• Extended the srsLTE open-source SDR platform with sidelink PHY layer implementation compliant with 3GPP LTE Release 12.
• Implemented Physical Sidelink Shared Channel (PSSCH) using SC-FDMA waveforms and integrated PSCCH for control signaling.
• Designed a relay UE capable of receiving downlink data from the eNodeB and retransmitting it via the sidelink to a remote UE.
• Developed a dynamic mode selection mechanism in the remote UE to switch between direct downlink (eNodeB) and D2D relay (relay UE) based on network conditions.
• Built GUI controllers using GTK+ 3.0 and Linux socket communication for real-time adjustment of frequency, gain, MCS index, PRBs, and RNTI.
• Utilized USRP hardware with UHD driver for real-time radio transmission and reception across all nodes in the testbed.

Experimental results

Research questions

• RQ1 Can a fully compliant LTE Release 12 sidelink be implemented on an open-source SDR platform?
• RQ2 How does D2D relaying via a relay UE affect SNR, throughput, and BLER compared to direct downlink communication?
• RQ3 What is the achievable range extension of the cell using D2D relay functionality?
• RQ4 How effective is dynamic mode selection between downlink and sidelink based on real-time channel conditions?
• RQ5 Can real-time parameter control via GUIs enable flexible experimentation for D2D and proximity services?

Key findings

• The implementation successfully achieved LTE Release 12-compliant sidelink communication using SDR, marking the first such implementation.
• D2D relaying via a relay UE extended cell coverage, enabling connectivity in low-SNR edge areas.
• Throughput and SNR performance were quantified for both direct downlink and relayed D2D links, providing performance benchmarks.
• Block Error Rate (BLER) measurements were collected and analyzed as a key metric for mode selection decisions.
• The GUI-based real-time control system enabled dynamic adjustment of radio parameters such as MCS index, frequency, gain, and PRBs across all nodes.
• The system demonstrated the feasibility of using open-source SDR platforms for prototyping and testing D2D and relaying functionalities in LTE networks.