Contents

Executive Summary / Introduction

Terminology 

1. Assumptions and Scope 

2. Industry background 

2.1. Standards

2.2. GSMA

3. LTE Roaming Basics

3.1. Negotiation 

3.1.1. Roaming Agreements

3.1.2. Tariff Negotiation

3.1.3. Document Exchange

3.2. Test Prep

3.2.1. Exchange of SIM/USIM cards

3.2.2. Establish Interconnection

3.2.3. Schedule testing

3.3. Testing (Network and Device) 

3.4. Billing Testing and Prep

3.5. Launch

3.6. Ongoing

4. IPX

4.1. Diameter Signalling in LTE Roaming

4.2. The QoS Paradigm in LTE

5. LTE Roaming Architecture 

5.1. LTE Data Roaming 

5.2. VoLTE Roaming

5.2.1. RAVEL/LBO Architecture

5.2.2. S8HR Architecture

5.3. SMS over LTE Roaming and Architecture

6. LTE Devices and USIM cards – Roaming Considerations

6.1. One Multimode Multi-band Device to Enable Global Roaming 

6.1.1. Multimode Single Device

6.1.2. Multiband Consideration

6.2. Voice Service in Roaming

6.2.1. One Device, All Voice Solutions 

6.2.2. LTE Dual-SIM – Global and Regional Roaming Enabler 

7. LTE Roaming Clearing and Settlement

7.1. Data Over LTE

7.2. VoLTE and SMSoIP

7.3. Accounting Flows for Non-IMS (Data over LTE) and IMS (VoLTE and SMSoIP)

7.3.1. Non-IMS Home Routing (Data over LTE)

7.3.2. IMS Services (S8) Home Routing (VoLTE/SMSoIP) 

7.3.3. IMS Services Local Breakout (VoLTE/SMSoIP) 

8. LTE Roaming Fraud

9. GTI Observations and Conclusions