UTRAN

Universal Terrestrial Radio Access Network

Radio Access Network →
Introduced in R99 Also in: Radio Access Network, Core Network, Services

UTRAN is the Universal Terrestrial Radio Access Network for 3G UMTS, comprising Node Bs and RNCs to handle all radio-related functions and connect user equipment to the core network.

Category
Radio Access Network
Introduced
R99
Where
Management
Also touches
3 segments
Specifications
190 specs
UTRAN Description Purpose Related Classification Detected Changes Specifications

Description

The Universal Terrestrial Radio Access Network (UTRAN) is the collective term for the network infrastructure that provides the radio access capabilities for User Equipment (UE) in a 3G UMTS network. It is one of the key subsystems defined by 3GPP, alongside the Core Network (CN) and the UE. UTRAN's primary components are the Node B (the base station) and the Radio Network Controller (RNC). These elements work together to manage the radio interface (UTRA) and facilitate the connection of mobile users to core network services.

Architecturally, UTRAN is structured around the concept of control points. The RNC is the controlling network element for one or more Node Bs. It hosts the critical Radio Resource Control (RRC) protocol layer and is responsible for centralized radio resource management (RRM) decisions, including admission control, packet scheduling, handover control, and power control settings. The Node B is responsible for the physical layer processing of the UTRA interface: modulation/demodulation, coding/decoding, spreading/despreading, and the transmission/reception of radio signals via its cells. The interface between the RNC and Node B is called the Iub interface, which is open and standardized to allow multi-vendor interoperability. For communication between RNCs (e.g., during inter-RNC handover), the Iur interface is used. The entire UTRAN connects to the Core Network via the Iu interface, which is logically separated into Iu-CS for circuit-switched domains (MSC) and Iu-PS for packet-switched domains (SGSN).

UTRAN operates by establishing and maintaining Radio Access Bearers (RABs) between the UE and the CN. When a UE wishes to communicate, the RNC, upon request from the CN, sets up the necessary radio resources across the involved Node B(s) and configures the UE's RRC connection. It manages mobility through procedures like cell selection/reselection, soft handover (a hallmark of WCDMA where a UE is connected to multiple cells simultaneously), and hard handover. UTRAN also handles security functions like ciphering and integrity protection over the radio interface. Its role is to abstract the complexities of the radio link from the core network, providing it with a reliable transport service for user data and signaling, while efficiently utilizing the scarce radio spectrum through advanced RRM techniques.

Purpose & Motivation

UTRAN was created to provide the network architecture necessary to realize the capabilities of the new UTRA radio interface for 3G UMTS. Its purpose was to move beyond the simpler Base Station Subsystem (BSS) of 2G GSM, which consisted of Base Transceiver Stations (BTS) and Base Station Controllers (BSC). The new architecture was needed to support the more complex radio resource management required by WCDMA, such as soft handover and fast power control, and to enable higher data rates and new packet-switched services.

It solved several key problems of previous architectures. The separation of the control intelligence (RNC) from the radio transmission/reception unit (Node B) allowed for more centralized and efficient resource management across multiple cells. The introduction of the open Iub and Iur interfaces promoted vendor competition and flexibility in network deployment. Most importantly, UTRAN was designed to simultaneously support both traditional circuit-switched voice and emerging packet-switched data services with appropriate Quality of Service (QoS) handling, a fundamental requirement for the 3G vision of multimedia communications.

The historical context is the evolution from GSM. While GSM's BSS was optimized for voice, UTRAN was conceived in the late 1990s as part of the IMT-2000 initiative to create a network capable of broadband data. It provided the essential framework that allowed operators to deploy UMTS networks globally. UTRAN's architecture proved robust and extensible, supporting major evolutionary upgrades like High-Speed Packet Access (HSPA) without fundamental changes. It served as the dominant 3G RAN for over a decade, forming a critical bridge between 2G and the flatter, all-IP architecture of 4G LTE (E-UTRAN).

Classification

Part ofUTRA
Specific typesATMDBSSDRNSDRTEUTRANGERANHOWMNBRNCSABPSHCCHSRNSU-LSADFU-PRCFUMTSURAN
Related approachesRNC

Detected Changes Across Releases

from 3GPP Change Requests

Specific changes extracted from the „Change history“ tables of 3GPP specifications (58 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.

Rel-15 32 changes

In Release 15, specific updates for UTRAN were limited, with the primary change being the addition of a `peeParametersList` attribute to its Network Resource Model. The release's focus was overwhelmingly on evolving E-UTRAN to support 5G, including its connection to the 5G Core Network and enabling EN-DC (E-UTRA-NR Dual Connectivity), rather than introducing new UTRAN radio capabilities.

  • Add attribute peeParametersList to UTRAN NRM SS TS 28.653CR0018
  • Update E-UTRAN SS definitions to support ng-eNB management TS 28.659CR0025
  • E-UTRA - NR Cell Resource Coordination TS 36.300CR1122
  • Introduction of New Radio Access Technology in TS 36.300 TS 36.300CR0998
  • Introduction of E-UTRA connected to 5GCN TS 36.300CR1151
  • Introduction of E-UTRA connected to 5GCN TS 36.304CR0419

+ 26 more changes

Rel-16 12 changes

In Release 16, UTRAN-related enhancements focused on mobility and interworking, specifically introducing UE UTRAN FDD measurements to enable SRVCC handovers from NR to UMTS. Furthermore, the release delivered "even further mobility enhancements in E-UTRAN" and finalized corrections to this feature. It also introduced procedures for UE Radio Capability Mapping to support EN-DC (E-UTRA-NR Dual Connectivity).

  • Add measurements related to Secondary Node Addition for E-UTRA-NR Dual Connectivity TS 32.425CR0184
  • Introduction of even further mobility enhancement in E-UTRAN TS 36.300CR1270
  • Introduction of LTE-based 5G terrestrial broadcast TS 36.331CR4190
  • Introduction of Even further Mobility enhancement in E-UTRAN TS 36.331CR4205
  • Introduction of UE UTRAN FDD measurements for SRVCC from NR to UMTS TS 38.215CR0027
  • Corrections to LTE terrestrial broadcast TS 36.214CR0056

+ 6 more changes

Rel-17 7 changes

In Release 17, UTRAN-related updates focused on enhancing security signaling by decoupling UE Security Capabilities from UE Radio Access Capabilities to avoid unintended linkages. Furthermore, the specifications introduced refined requirements to protect against active attacks on the radio interface, such as those involving signaling manipulation or a false base station. These changes aimed to strengthen the system against eavesdropping, masquerading, and unauthorized data modification.

  • Introduction of new bands and bandwidth allocation for LTE-based 5G terrestrial broadcast TS 36.300CR1360
  • Introduction of new bands and bandwidth allocation for LTE-based 5G terrestrial broadcast TS 36.331CR4750
  • Support of Non-Terrestrial Network in NB-IoT and eMTC TS 36.331CR4771
  • UE capabilities for new bands and bandwidth allocation for LTE-based 5G terrestrial broadcast TS 36.331CR4780
  • Addition of missing functionalities and corrections to support of Non-Terrestrial Network in NB-IoT and eMTC TS 36.331CR4798
  • UE Security Capabilities signaling in E-UTRAN [UE_Sec_Caps] TS 36.300CR1359

+ 1 more changes

Rel-18 3 changes

In Release 18, the primary new development for UTRAN was the introduction of enhanced security protections against improper reselection to legacy networks like GERAN and UTRAN. This specifically addressed active attack threats where an intruder could manipulate radio interface signalling or masquerade as a network element, such as a false base station, to force such reselections. These measures aimed to protect the confidentiality and integrity of user data and signalling against these sophisticated attacks on the radio access link.

  • Protection against improper reselection to GERAN/UTRAN [RESELECTION_TO GSM_AND_UTRAN] TS 36.304CR0866
  • Protection against improper reselection to GERAN/UTRAN [RESELECTION_TO GSM_AND_UTRAN] TS 36.331CR4971
  • CR on E-UTRAN measurement in IoT NTN TS 36.214CR0058
Rel-19 4 changes

In Release 19, UTRAN introduced new capabilities to support redirection and handover to Non-Terrestrial Networks (NTN) for NB-IoT devices. Specifically, the release defined mechanisms for an E-UTRAN cell to indicate its support for NB-IoT satellite (NTN) bands and to redirect devices from a terrestrial network to an NB-IoT NTN. These enhancements ensure seamless service continuity for NB-IoT devices by integrating satellite access information into the terrestrial radio access network procedures.

  • Introduction of NB-IoT satellite information in E-UTRAN [EUTRAN-to-NBIoTNTN] TS 36.300CR1427
  • Introduction of NB-IoT satellite information in E-UTRAN [EUTRAN-to-NBIoTNTN] TS 36.331CR5140
  • Correction for the redirection from E-UTRAN TN to NB-IoT NTN [IoT_TN_NTN_redir] TS 36.331CR5173
  • Indication of supported NB-IoT NTN band list in E-UTRAN [IoT_TN_NTN_redir] TS 36.331CR5183

Explore further

Broader topics and technologies where UTRAN plays a role.

Topics
RRC (Radio Resource Control)Spectrum & CoexistenceLTE / LTE-AdvancedLawful InterceptUMTS / WCDMAManagement & Operations
Technologies
LTE

Defining Specifications

3GPP specifications that define or reference UTRAN, with the latest known release. Sourced from the 3GPP document catalog — see methodology.

SpecificationTitleRelease
TS 21.133 v1400 3G Security Requirements Rel-5
TR 21.905 vj00 3GPP Technical Terms and Definitions Rel-19
TS 22.100 v1320 UMTS Service Requirements Phase 1 Rel-4
TS 22.240 vj00 3GPP Generic User Profile Requirements Rel-19
TR 22.945 v1300 Fax Services Guidance for GSM/UMTS Rel-4
TR 22.980 vj00 Network Composition Feasibility Study Rel-19
TS 23.034 vj00 HSCSD Stage 2 Service Description Rel-19
TS 23.060 vj00 GPRS Service Description Stage 2 Rel-19
TS 23.107 vj00 UMTS QoS Framework Rel-19
TS 23.110 vj00 Access Stratum Services Specification Rel-19
TS 23.171 v1300 LCS Stage 2 Specification for UMTS Rel-4
TS 23.205 vj00 Bearer Independent CS Core Network Stage 2 Rel-19
TS 23.207 vj00 End-to-End QoS Framework for GPRS Rel-19
TS 23.221 vj00 3GPP System Architectural Requirements Rel-19
TS 23.228 vj50 IMS Stage-2 Service Description Rel-19
TS 23.231 vj00 SIP-I based CS core network stage 2 Rel-19
TS 23.251 vj00 Network Sharing Stage 2 Specification Rel-19
TS 23.271 vj00 LCS Stage 2 Specification Rel-19
TS 23.851 v1600 Network Sharing Architecture for 3G Systems Rel-6
TR 23.908 v1400 Pre-paging in GSM/UMTS networks Rel-5
TR 23.923 v1300 Mobile IP+ Feasibility Study for UMTS/GPRS Rel-4
TR 23.976 vj00 Push Service Requirements Analysis Rel-19
TR 23.979 vj00 PoC over 3GPP Systems Architectural Requirements Rel-19
TS 24.161 vj00 Network-Based IP Flow Mobility (NBIFOM) Rel-19
TS 24.206 v1700 Voice Call Continuity Between CS and IMS Rel-7
TS 25.123 vj00 Radio Resource Management for TDD Rel-19
TS 25.133 vj00 UTRAN RRM Requirements for FDD Rel-19
TS 25.171 vj00 A-GPS Minimum Performance Requirements for UTRA FDD UE Rel-19
TS 25.172 vj00 A-GANSS UE Minimum Performance Requirements (FDD) Rel-19
TS 25.173 vj00 A-GANSS Performance Requirements (TDD) Rel-19
TS 25.201 vj00 UTRA Physical Layer General Description Rel-19
TS 25.211 vj00 UTRA FDD Layer 1: Transport & Physical Channels Rel-19
TS 25.214 vj00 UTRA FDD Physical Layer Procedures Rel-19
TS 25.221 vj00 UTRA TDD Physical Layer Specification Rel-19
TS 25.224 vj00 UTRA TDD Physical Layer Procedures Rel-19
TS 25.225 vj00 UTRA TDD Physical Layer Measurements Rel-19
TS 25.301 vj00 UE-UTRAN Radio Interface Protocol Architecture Rel-19
TS 25.302 vj00 UTRA Physical Layer Services Rel-19
TS 25.304 vj00 UTRA Idle Mode Procedures Specification Rel-19
TS 25.305 vj00 UTRAN UE Positioning Stage 2 Rel-19
TS 25.306 vj00 UE Radio Access Capabilities Specification Rel-19
TS 25.321 vj00 MAC Protocol Specification for UTRAN Rel-19
TS 25.322 vj00 RLC Protocol Specification Rel-19
TS 25.323 vj00 Packet Data Convergence Protocol (PDCP) Specification Rel-19
TS 25.331 vj00 UTRAN RRC Protocol Specification Rel-19
TS 25.367 vj00 Home NodeB Mobility Procedures Rel-19
TS 25.401 vj00 UTRAN Overall Architecture Rel-19
TS 25.402 vj00 UTRAN Synchronisation Mechanisms Rel-19
TS 25.410 vj00 Iu Interface Introduction for UTRAN Rel-19
TS 25.413 vj00 Radio Access Network Application Part (RANAP) Rel-19
TS 25.420 vj00 Iur Interface Introduction for UTRAN Rel-19
TS 25.423 vj00 UTRAN RNSAP Specification Rel-19
TS 25.430 vj00 Introduction to Iub Interface Specifications Rel-19
TS 25.433 vj00 Node B Application Part (NBAP) Protocol Rel-19
TS 25.434 vj00 UTRAN Iub Interface Data Transport and Signalling Rel-19
TS 25.450 vj00 Iupc Interface Introduction for UTRAN Positioning Rel-19
TS 25.452 vj00 Iupc Interface Signalling Transport for PCAP Rel-19
TS 25.453 vj00 PCAP Protocol Specification Rel-19
TS 25.766 vd10 Network-Assisted Interference Cancellation for UMTS Rel-13
TS 25.820 v820 3G Home NodeB Study Report Rel-8
TS 25.866 v1900 1.28Mcps TDD Home NodeB Study Report Rel-9
TS 25.874 vb00 HSPA Feedback & Signalling Efficiency for LCR TDD Rel-11
TR 25.903 vj00 Continuous Connectivity for Packet Data Users Rel-19
TR 25.912 vj00 Evolved UTRA and UTRAN Technical Report Rel-19
TR 25.927 ve00 Energy Saving Solutions for UMTS Node B Rel-14
TR 25.929 vj00 Continuous Connectivity for Packet Data Users Rel-19
TR 25.931 vj00 UTRAN Signalling Procedures Examples Rel-19
TR 26.902 vj00 Video Codec Performance for 3GPP Packet Services Rel-19
TR 26.936 vj00 Audio Codec Characterization Technical Report Rel-19
TR 26.937 vj00 3GPP PSS Characterization Rel-19
TR 26.952 vj00 EVS Codec Selection, Verification & Characterization Rel-19
TR 26.976 vj00 AMR-WB Codec Characterization & Verification Rel-19
TS 28.606 vc10 CN and non-3GPP interworking NRM IRP Solution Sets Rel-12
TS 28.616 vj00 EPC and non-3GPP access NRM IRP SS definitions Rel-19
TS 28.621 vj00 Generic Network Resource Model (NRM) IRP Requirements Rel-19
TS 28.626 vj00 State Management Data Definition IRP Solution Set Rel-19
TS 28.632 vj00 Inventory Management NRM Integration Reference Point Rel-19
TS 28.651 vj00 UTRAN Network Resource Model Requirements Rel-19
TS 28.652 vj00 UTRAN Network Resource Model (NRM) IRP Information Service Rel-19
TS 28.653 vj00 UTRAN NRM IRP Solution Set Definition Rel-19
TS 28.656 vj00 GERAN NRM IRP Solution Set Definitions Rel-19
TS 28.659 vj00 E-UTRAN NRM IRP Solution Set Definitions Rel-19
TS 28.661 vj00 Generic RAN NRM IRP Requirements Rel-19
TS 28.662 vj10 Generic RAN Network Resource Model (NRM) IRP IS Rel-19
TS 28.672 vj00 HNS NRM IRP Information Service Rel-19
TS 28.702 vj00 Core Network NRM IRP Information Service Rel-19
TS 28.703 vj00 Core Network NRM IRP Solution Set Definitions Rel-19
TS 28.706 vj00 IMS NRM IRP Solution Set definitions Rel-19
TS 28.707 vj00 EPC NRM IRP Requirements Rel-19
TS 28.733 vj00 TN NRM IRP Solution Set Definitions Rel-19
TS 28.736 vj00 STN Interface NRM IRP Solution Set Definitions Rel-19
TS 29.060 vj00 GPRS Tunnelling Protocol (GTP) version 1 Rel-19
TS 29.281 vj20 GTPv1-U Protocol Specification Rel-19
TS 31.121 vi50 UICC-terminal interface test specification Rel-18
TS 32.102 vj00 Telecom Management Physical Architecture Framework Rel-19
TS 32.250 vj00 Circuit Switched Offline Charging Rel-19
TS 32.251 vj00 PS Domain Charging Management Rel-19
TS 32.271 vj20 3GPP LCS Charging Management Spec Rel-19
TS 32.272 vj00 Charging for Push-to-Talk over Cellular (PoC) Rel-19
TS 32.278 vj00 Monitoring Events Offline Charging Specification Rel-19
TS 32.293 vj00 Proxy Function in Domestic Service Provider Rel-19
TS 32.401 vj00 Performance Management Concept & Requirements Rel-19
TS 32.404 vj00 Performance Management Definitions & Template Rel-19
TS 32.405 vj00 UTRAN Performance Measurements Specification Rel-19
TS 32.406 vj00 Performance Management for CN PS Domain Rel-19
TS 32.407 vj00 PM; CN CS Domain; UMTS/GSM measurements Rel-19
TS 32.408 vj00 UMTS/GSM Performance Management Measurements Rel-19
TS 32.410 vj00 3GPP TS 32.410: Key Performance Indicators (KPI) Rel-19
TS 32.425 vj00 E-UTRAN Performance Measurements Rel-19
TS 32.426 vj00 EPC Performance Measurements Specification Rel-19
TS 32.450 vj00 E-UTRAN Key Performance Indicators (KPI) Definitions Rel-19
TS 32.451 vj00 KPI Requirements for E-UTRAN Rel-19
TS 32.582 vj00 HNB Management Information Model for Type 1 Interface Rel-19
TS 32.584 vj00 HNB OAM&P XML Definitions for Type 1 Interface Rel-19
TS 32.592 vj00 HeNB OAM&P Information Model Rel-19
TS 32.594 vj00 Data definitions for HeNB to HeMS Type 1 interface Rel-19
TS 32.615 v1920 Bulk CM XML File Format Definition Rel-9
TS 32.616 vj00 Bulk CM IRP Solution Set Definitions Rel-19
TS 32.625 v1900 Bulk CM XML File Format Definition Rel-9
TS 32.626 vb20 Generic Network Resources IRP Solution Set Definitions Rel-11
TS 32.632 vb00 Core Network Resources IRP: Network Resource Model Rel-11
TS 32.635 v1910 Core Network Resources IRP XML Schema Rel-9
TS 32.636 vb00 CM Core Network Resources IRP Solution Set Rel-11
TS 32.641 vb00 UTRAN Network Resources IRP Requirements Rel-11
TS 32.642 vb50 UTRAN Network Resource Model for Configuration Management Rel-11
TS 32.645 v930 UTRAN Bulk CM XML File Format Rel-9
TS 32.646 vc00 UTRAN NRM IRP Solution Set Definitions Rel-12
TS 32.655 v920 GERAN NRM Bulk CM XML File Format Rel-9
TS 32.656 vc00 GERAN NRM IRP Solution Set Definitions Rel-12
TS 32.675 v1900 State Management IRP Bulk CM XML Format Rel-9
TS 32.676 vc00 3GPP TS 32.676: State Management IRP Solution Set Rel-12
TS 32.692 vb00 Inventory Management NRM IRP Specification Rel-11
TS 32.715 v900 TN interface NRM IRP XML file format definition Rel-9
TS 32.716 vb00 TN NRM IRP Solution Set Definitions Rel-11
TS 32.721 vb00 Repeater Network Resources IRP Requirements Rel-11
TS 32.725 v1900 Repeater Network Resources IRP Bulk CM XML Rel-9
TS 32.726 vb00 Repeater NRM IRP Solution Set Definitions Rel-11
TS 32.732 vb00 IMS Network Resource Model IRP: Information Service Rel-11
TS 32.735 v1910 IMS NRM IRP Bulk CM XML Format Rel-9
TS 32.736 vb00 IMS NRM IRP Solution Set Definitions Rel-11
TS 32.741 vb00 STN Interface NRM IRP Requirements Rel-11
TS 32.745 v900 STN NRM IRP XML File Format Definition Rel-9
TS 32.746 vb00 STN NRM IRP Solution Set Definitions Rel-11
TS 32.751 vb00 EPC NRM IRP Requirements Rel-11
TS 32.765 v960 E-UTRAN NRM IRP XML Definitions Rel-9
TS 32.766 vb90 E-UTRAN NRM IRP Solution Set Definitions Rel-11
TS 32.772 vb00 HNS Network Resource Model (NRM) IRP Rel-11
TS 32.791 vb00 Common RAT NRM IRP Requirements Rel-11
TS 32.792 vb10 Generic RAN Network Resource Model (NRM) IRP Rel-11
TS 32.808 v1800 Common User Profile Storage Framework Rel-8
TS 32.821 v1900 SON OAM Architecture for Home NodeB Rel-9
TS 32.826 va00 Study on Energy Savings Management in LTE/SAE Networks Rel-10
TS 33.102 vj10 3G Security Architecture Specification Rel-19
TS 33.108 vj00 LI Handover Interface Specification Rel-19
TS 33.320 vj00 H(e)NB Subsystem Security Architecture Rel-19
TS 33.401 vj10 EPS Security Architecture Rel-19
TS 33.820 v1830 Home NodeB/eNodeB Security Architecture Rel-8
TS 33.856 vg10 Security for 5G to 3G Voice Continuity Rel-16
TS 33.859 vb10 UTRAN Key Hierarchy Enhancement Study Rel-11
TS 36.101 vj30 LTE UE Radio Transmission & Reception Requirements Rel-19
TS 36.102 vj10 E-UTRA UE Satellite Access RF Requirements Rel-19
TS 36.116 vj00 E-UTRA Relay RF Requirements Rel-19
TS 36.117 vj00 E-UTRA Relay RF Test Methods & Requirements Rel-19
TS 36.133 vj20 E-UTRA RRM Requirements Rel-19
TS 36.214 vj00 E-UTRA Physical Layer Measurements Rel-19
TS 36.300 vj00 E-UTRAN Radio Interface Protocol Architecture Overview Rel-19
TS 36.302 vj00 E-UTRA Physical Layer Services Rel-19
TS 36.304 vj00 UE Idle Mode Procedures in E-UTRA Rel-19
TS 36.331 vj00 LTE RRC Protocol Specification Rel-19
TS 36.521 vj00 E-UTRA UE Conformance ICS Proforma Rel-19
TS 36.887 vc00 Energy Saving Enhancement for E-UTRAN Study Rel-12
TS 36.896 ve00 Study on Flexible eNB-ID and Cell-ID in E-UTRAN Rel-14
TR 36.927 vj00 Network Energy Saving for E-UTRAN Rel-19
TS 36.938 v900 E-UTRAN to 3GPP2/Mobile WiMAX Mobility Rel-9
TS 37.320 vj00 Minimization of Drive Tests (MDT) Overview Rel-19
TS 37.571 vj00 UE Conformance for Positioning Rel-19
TR 37.901 vf10 UE Application Layer Data Throughput Performance Rel-15
TS 38.215 vj10 NR Physical Layer Measurements Rel-19
TR 38.889 vg00 NR-based access to unlicensed spectrum study Rel-16
TS 43.051 vj00 GERAN Stage 2 Service Description Rel-19
TS 43.129 vj00 PS Handover in GERAN A/Gb and GAN Modes Rel-19
TS 43.130 vj00 Iur-g Interface Overview Rel-19
TS 43.318 vj00 Generic Access Network (GAN) Stage 2 Rel-19
TR 43.901 vj00 Generic Access to A/Gb Interface Feasibility Study Rel-19
TS 44.060 vj00 GERAN RLC/MAC Protocol Specification Rel-19
TS 44.160 vg00 GERAN Iu Mode RLC/MAC Protocol Specification Rel-16
TS 44.318 vj00 Generic Access Network (GAN) Interface Procedures Rel-19
TR 44.901 vj00 Extended NACC for External Cell Change Rel-19
TR 45.902 vj00 Flexible Layer One (FLO) for GERAN Rel-19
TS 48.008 vj00 BSS-MSC Interface Layer 3 Procedures Rel-19