LTE pre-SI Test Suite Implementation in TTCN3: A case study 1 Pramod Shrivastava Intel Mobile Communication Nitin Bodas Larsen & Toubro Infotech Ranganath Mahapatra Larsen & Toubro Infotech

Introduction 2 LTE pre-System Integration (pre-SI) test suite for testing UE modem in a simulated environment. Specifically designed to address IOT, field testing, inter-RAT scenarios and testing of complex functional areas. Implemented on a multi-mode LTE protocol stack running on a host system and interacting with an automation framework through message queues. The main objective of this suite was to advance the testing phase, typically carried out at a later stage and thereby improve the overall testing process. The test cases were developed in TTCN3.

UE Modem Development & Validation Phases 3 Protocol Layers Physical and RF Layer Advance Features OS Porting & Peripherals Conformance Testing Field Testing Performance & Stress Testing IOT Certification Support Requirement Testing Operator Acceptance Testing Pre-SISIPost-SI  Pre-SI phase: Protocol layers such as Physical Layer, L2 and L3 consisting of MAC, RRC, RLC, NAS & PDCP layers are developed independently  SI Phase: Protocol layers (L2 &3) are integrated with physical layer, RF and other components or modules and ported to UE modem  Post-SI Phase: the UE modem undergoes development and validation with focus on customer acceptance, certification testing etc.  Pre-SI phase: Protocol layers such as Physical Layer, L2 and L3 consisting of MAC, RRC, RLC, NAS & PDCP layers are developed independently  SI Phase: Protocol layers (L2 &3) are integrated with physical layer, RF and other components or modules and ported to UE modem  Post-SI Phase: the UE modem undergoes development and validation with focus on customer acceptance, certification testing etc.

Incremental Development & Testing 4 Test Case Execution Protocol Stack Development/Enhancement  Release 8  Release 9  Release 10 Test Case Development/Enhancement  Phase-1  Phase-2  Phase-3  ……… Host Environment Development  Phase-1  Phase-2  Phase-3  ………

3GPP Releases & Features covered in the Test Suite 5 LTE/EPC Rel. 8 LTE/EPC Rel. 9LTE/EPC Rel. 10  LTE FDD & TDD Interfaces  LTE FEDD & TDD Layer 1,2,3 delimitations  Security support  Mobility Features & IRAT  EPC Definition and support  EPC charging  Advanced Antenna,: MIMO, FSS  CS Fall Back  SRVCC  SON Features  Home eNB  IMS Support  Positioning Support  LTE in 800 MHz  NW based Positioning  IMS Emergency  Public Warning System  Home eNB  eMBMS support in LTE  Enhanced DL Transmission  Vocoder rate adaptation  SON Features  Bandwidth aggregation  Relays and Repeaters  MIMO Enhancements  Multisite Cooperative  Transmission  Incremental approach to develop the stack, network emulator and test suite.  Synced up with 3GPP releases with respect to feature enhancements and addition of new features.  Test Cases categorized into complex functional, IOT, security, inter-RAT, field testing and other functional areas.  Incremental approach to develop the stack, network emulator and test suite.  Synced up with 3GPP releases with respect to feature enhancements and addition of new features.  Test Cases categorized into complex functional, IOT, security, inter-RAT, field testing and other functional areas.

Filtering of Test Cases 6  Complex Functional Test Cases  Field Test Cases  IOT Test Cases  GCF Test Cases  Pre-SI Phase 1  Pre-SI Phase 2  Pre-SI Phase 3 SI Test Cases Influenced Test Cases Non-Influenced Test Cases

Test Environment 7 System Adaptation Layer 4G LTE (PDCP/RLC/MAC) MAC Adaptation Layer System Adaptation Layer 2G/3G/ L2 Layer L1 System Adaptation Layer / NAS Layer 3 Layer 2 MAC Adaptation Layer Pre-SI Test Suite in TTCN-3 AT/MMI Commands 2G/3G/4G UE MSG Q or UDP/IP Network Side Emulator  The test cases are executed using host based tri-mode automation framework.  It supports validation of both LTE and legacy technologies.  The framework and UE protocol stack interact with each other in message queues and also preserves LTE frame timing.  The test cases are executed using host based tri-mode automation framework.  It supports validation of both LTE and legacy technologies.  The framework and UE protocol stack interact with each other in message queues and also preserves LTE frame timing.

Sample Scenario#1 8 CS-fall back FTP Download MT Voice Call Voice Call End Web Browsing LTE [Packet Call] CS-FB callUMTSAdd a bearer End CS-FB call back to LTE with both bearers.

Sample Scenario#2 UE circulates around cells of different RATs 9

Addressing Challenges  Test scenario identification is one of the key challenges in the development of the pre-SI Test suite due to limitations and evolution of protocol stack or host environment.  These challenges are addressed ensuring the following aspects:  Extensive knowledge of standard and release enhancements in multi RAT context  Extensive knowledge in SI and post-SI test areas  Test coverage to replicate field or real life scenarios including negative and concurrent scenarios etc  Test cases were converted in to message flows followed by scripting which requires excellent understanding of the interaction between UE modem and network. 10

Conclusion Pre-SI test suite was developed with test scenarios typically executed in SI and post-SI phases. The objective of this suite is to reduce multimode LTE UE development time. The test suite is designed such that it can also be used in SI and post-SI phase on commercial network simulator. The suite is continually enhanced to keep in sync with the evolution of 3GPP standard. 11

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