LTE Security, Second Edition

Chapter 14

Relay Node Security

Since the first edition of this book was published in 2010, a major architectural enhancement of Long Term Evolution (LTE) has been introduced: relay nodes (RNs). RNs are base stations that are connected to the core network via a wireless link.

In Section 14.1, we briefly introduce the basic architecture selected by the 3rd Generation Partnership Project (3GPP) for the deployment of RNs in LTE. In Section 14.2, we discuss the security solution for RNs in detail. For possible future work on mobile and multi-hop RNs, we refer to Section 16.1.1.

14.1 Overview of Relay Node Architecture

14.1.1 Basic Relay Node Architecture

[TS23.401], the 3GPP specification for the Evolved Packet System (EPS) architecture, describes relaying as follows:

The relaying function enables an operator to improve and extend the coverage area by having a Relay Node (RN) wirelessly connected to an eNB serving the RN, called Donor eNB (DeNB), via a modified version of the E-UTRA radio interface called the Un interface …

The relaying function and use of RN/DeNB entities in a network is transparent to the operations of the UEs connected to it and associated core network entities¹…

The relaying function was first proposed in the study on ‘LTE-advanced’ features in [TR36.912]. Figure 14.1, which has been adapted from Figure 9.1-1 in [TR36.912], shows the position of an RN in relation to the User Equipment (UE), the Donor Evolved NodeB (DeNB) and the Evolved Packet Core (EPC). UE, evolved ...