Description
An Implementation Conformance Statement (ICS) is a detailed, structured document that specifies the extent to which a particular implementation (e.g., a piece of User Equipment, a base station, or a network node) conforms to a given 3GPP technical specification. It is a critical component of the conformance testing process, providing a clear declaration of implemented protocol features, functions, and options. The ICS is typically presented in a proforma format defined by 3GPP, which lists all mandatory and optional requirements from the base specification. For each requirement, the implementer indicates whether it is supported, not supported, or conditionally supported, along with any limitations or observations. The ICS serves as a reference for test laboratories when designing and executing conformance test cases, ensuring that testing focuses on the claimed capabilities. In 3GPP, ICS documents are specified across various technical areas, including radio access (e.g., LTE, NR), core network protocols, and security features. The process involves referencing multiple test specifications (e.g., 36.523 for LTE radio protocol) to verify that the implementation behaves correctly under defined conditions. By providing transparency, the ICS facilitates interoperability in multi-vendor environments, as network operators can verify that equipment from different suppliers adheres to the same standards.
Purpose & Motivation
The ICS concept was adopted to address the challenge of ensuring interoperability in complex, multi-vendor telecommunications systems. As 3GPP specifications grew in scope and optional features proliferated, it became impractical to test every possible implementation detail. The ICS provides a standardized way for vendors to declare their implementation's capabilities, streamlining the conformance testing process. It helps test laboratories target relevant test cases, reduces testing time and cost, and increases confidence that products will work together in live networks. Historically, without such declarations, interoperability issues often arose post-deployment, leading to service disruptions and increased integration efforts. The ICS, introduced from early 3GPP releases like R99, formalizes the conformance assessment framework, supporting global certification programs (e.g., GCF, PTCRB) and ensuring that mobile devices and infrastructure meet minimum performance and compatibility standards.
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (241 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the ICS (Implementation Conformance Statement) function saw the introduction of specific conformance test procedures for new physical layer features, including PUSCH and PUCCH formats for NR, as well as tests for 1024QAM and sTTI in E-UTRA. Furthermore, the release added ICS proforma tables for declaring FR2 multiband relaxation and integrated Physical Layer Baseline Implementation Capabilities for NR Carrier Aggregation, NR Dual Connectivity, and EN-DC. These updates ensured that the conformance testing framework kept pace with the new radio capabilities and configurations defined in the release.
- CR to TS 36.104: Implementation of UL PRB to DL PRB center offset for TDD NB-IoT TS 36.104CR4816
- CR for PUSCH conformance test in TS 36.141 for BS IC TS 36.141CR1080
- CR: SPUSCH conformance test for 36.141 TS 36.141CR1157
- CR: SPUCCH conformance test for 36.141 TS 36.141CR1158
- CR to TS 36.141: Implementation of UL PRB to DL PRB center offset for TDD NB-IoT TS 36.141CR1189
- Cleanup for BS IC conformance requirements TS 36.141CR1089
+ 9 more changes
In Release 16, the ICS function was expanded to include new implementation capabilities for EN-DC and NR standalone operation, such as support for inter-band EN-DC configurations, specific bands like n26 and n78A, and new UE capabilities like PUSCH Pi2 BPSK. It also introduced ICS proforma updates for handling inter-system changes between S1 and N1 interfaces and for flexible PDU-PDN handling. Furthermore, the release added conformance test details for procedures like iRAT RS-SINR measurements and corrected baseline capabilities for various multi-carrier and beam correspondence features.
- CR: Cleanup for NPUSCH format 1 conformance testing for multi-TB interleaved transmission in TS 36.141 TS 36.141CR1284
- Correction to n66 intra-band CA Physical Layer Baseline Implementation Capabilities TS 38.508CR0058
- EN-DC bands Implementation Conformance Statement (ICS) proforma Updates TS 38.508CR0054
- Physical Layer Baseline Implementation Capabilities for Beam Correspondence TS 38.508CR0053
- Addition of TDD-TDD PC2 inter-band EN-DC UE RF Baseline implementation Capabilities declaration TS 38.508CR0075
- Update NR intra-band contiguous CA implementation capabilities in 38.508-2 TS 38.508CR0079
+ 32 more changes
In Release 17, the ICS function was updated to introduce new common implementation conformance statements for NR-U (NR in Unlicensed Spectrum) and for Multi configured uplink grants in NR Industrial IoT. The release also expanded ICS coverage for carrier aggregation, with updates to implementation capabilities for various NR intra-band and inter-band CA configurations within FR1 and FR2. Furthermore, specific ICS additions were made for features like 1024QAM for NR FR1 base stations and PUSCH 256QAM for FR1, alongside updates to baseline capabilities and corrections to existing conformance requirements.
- Big CR for TS 36.141 for Rel-17 NB-IoT BS conformance testing TS 36.141CR1338
- CR for 37.141 on BS RF conformance testing for 1024QAM for NR FR1 TS 37.141CR0997
- CR to TS 37.145-2: implementation of LTE_upper_700MHz_A band 103 TS 37.145CR0322
- BigCR for TS38.104: Introduction of conformance testing requirements for FR1 PUSCH 256QAM TS 38.104CR0372
- CR to 37.141: BS RF conformance requirements for 1024QAM in FR1 TS 37.141CR1005
- CR to TS 37.145-2: Corrections to conformance requirements, Rel-17 TS 37.145CR0282
+ 76 more changes
In Release 18, the ICS function was updated with new physical layer and RF baseline implementation capabilities, including the introduction of new bands n100 and n101 for railway communications and numerous new carrier aggregation (CA) and EN-DC combinations for Power Classes 1.5 and 2. The release also added conformance requirements for NR Mobile Integrated Access and Backhaul (IAB) and IoT Non-Terrestrial Networks (NTN), while clarifying UE implementation PICS and updating the status of band and CA configurations in the ICS annexes.
- BigCR to TS 38.176-2 on RF conformance requirements for NR Mobile IAB TS 38.176CR0057
- BigCR on mIAB-MT radiated conformance requirement (TS38.176-2, Rel-18) TS 38.176CR0058
- Normative statements on FQDN format TS 23.003CR0653
- (LTE_NBIoT_eMTC_NTN_req) Collection of IoT-NTN SAN demodulation conformance requirements TS 36.181CR0022
- CR to TS 38.104 CR implementation correction TS 38.104CR0599
- Addition of R18 new NR-CA PC2 configs RF Baseline Implementation Capabilities TS 38.508CR0499
+ 74 more changes
In Release 19, the ICS function was expanded to incorporate new conformance testing requirements for Non-Terrestrial Networks (IoT_NTN_TDD) and Subband Full Duplex (SBFD) base stations. It introduced baseline implementation capabilities for new bands like n110, n87, n88, n13 PC2, and n25 PC2, as well as for new carrier aggregation combinations such as DC_1A-41A_n78A and various multi-band CA combos. Additionally, the release added requirements for U6GHz EEIRP conformance testing and updated RF baseline capabilities for EN-DC configurations.
- CR on RF conformance testing for TS 36.181 - IoT_NTN_TDD TS 36.181CR0039
- CR on the performance conformance testing for TS 36.181 - IoT_NTN_TDD TS 36.181CR0040
- CR to TS 37.145-2: implementation of the preferred test method and TRP annex improvements TS 37.145CR0415
- CR to TS 38.141-2 for introduction of U6GHz EEIRP conformance testing requirement TS 38.141CR0631
- (NR_duplex_evo-Perf) Big CR to 38.141-2 for addition of SBFD BS conformance requirements TS 38.141CR0691
- Update NR band and CADC configs status in ICS Annex B TS 38.508CR0838
+ 20 more changes
Explore further
Broader topics and technologies where ICS plays a role.
Defining Specifications
3GPP specifications that define or reference ICS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.801 vj00 | 3GPP Specification Drafting Rules | Rel-19 |
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 22.892 v800 | IMS Centralized Services Study | Rel-8 |
| TS 23.003 vj50 | Numbering, addressing and identification in 3GPP | Rel-19 |
| TS 23.272 vj10 | CS Fallback in EPS | Rel-19 |
| TS 23.292 vj00 | IMS Centralized Services (ICS) Architecture | Rel-19 |
| TS 23.719 ve00 | Study on Service Domain Centralization (SeDoC) | Rel-14 |
| TS 23.892 v1801 | IMS Centralized Services Control | Rel-8 |
| TS 23.893 v800 | IMS Multimedia Session Continuity Study | Rel-8 |
| TS 24.229 vj50 | IMS call control protocol based on SIP and SDP | Rel-19 |
| TS 24.286 vj00 | 3GPP TS 24.286: ICS Management Object | Rel-19 |
| TS 24.292 vj00 | IMS Centralized Services (ICS) Protocol | Rel-19 |
| TS 24.294 vj00 | IMS Centralized Services (ICS) I1 Interface Protocol | Rel-19 |
| TS 24.802 vc10 | IMS II-NNI Traversal Scenario Determination Study | Rel-12 |
| TS 29.162 vj00 | IMS-IP Network Interworking | Rel-19 |
| TS 29.163 vj00 | Interworking between 3GPP IM CN and CS networks | Rel-19 |
| TS 29.165 vj10 | Inter-IMS Network to Network Interface (NNI) | Rel-19 |
| TS 29.292 vj00 | IMS Centralized Services (ICS) Interworking | Rel-19 |
| TS 31.829 vd00 | ISIM Conformance Requirements Technical Report | Rel-13 |
| TS 32.240 vj40 | Charging Management Architecture & Principles | Rel-19 |
| TS 32.250 vj00 | Circuit Switched Offline Charging | Rel-19 |
| TS 33.838 vb00 | Study on Protection against Unsolicited Communication for IMS | Rel-11 |
| TS 34.121 v1970 | UE Conformance Spec for FDD Radio | Rel-9 |
| TS 34.123 vi30 | UE Conformance Specification | Rel-18 |
| TS 34.229 vj21 | IMS SIP/SDP UE Conformance Testing for 5GS | Rel-19 |
| TS 36.104 vj10 | Base Station (BS) radio transmission and reception | Rel-19 |
| TS 36.108 vj10 | Satellite Access Node RF Requirements | Rel-19 |
| TS 36.111 vj00 | LMU Requirements for UTDOA Positioning | 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 36.141 vj00 | E-UTRA BS Conformance Testing | Rel-19 |
| TS 36.181 vj30 | E-UTRA RF Test Methods for Satellite Access Node | Rel-19 |
| TS 36.521 vj00 | E-UTRA UE Conformance ICS Proforma | Rel-19 |
| TS 36.523 vj00 | UE Conformance Test Spec for Idle Mode | Rel-19 |
| TS 36.579 | 3GPP TR 36.579 | R99 |
| TS 37.104 vj10 | MSR Base Station RF Characteristics | Rel-19 |
| TS 37.141 vj10 | RF Test Methods for Multi-Standard Radio Base Stations | Rel-19 |
| TS 37.145 vj10 | AAS Base Station Conducted Conformance Testing | Rel-19 |
| TS 37.571 vj00 | UE Conformance for Positioning | Rel-19 |
| TS 37.579 vi40 | Mission Critical services conformance testing | Rel-18 |
| TS 37.802 va10 | MSR BS RF Requirements for Non-Contiguous Spectrum | Rel-10 |
| TS 37.809 vb00 | E-UTRA & MSR BS Class Requirements | Rel-11 |
| TS 37.812 vb30 | Multi-band Multi-standard Radio BS Requirements | Rel-11 |
| TR 37.900 vj00 | Multi-Standard Radio (MSR) Base Station Requirements | Rel-19 |
| TS 38.104 vj20 | NR Base Station RF Requirements | Rel-19 |
| TS 38.108 vj20 | NTN NR Satellite Access Node RF Requirements | Rel-19 |
| TS 38.141 vj20 | NR Base Station RF Conformance Testing Part 1 | Rel-19 |
| TS 38.174 vj10 | NR Integrated Access and Backhaul Radio Spec | Rel-19 |
| TS 38.176 vj20 | IAB Conformance Testing Specification | Rel-19 |
| TS 38.181 vj10 | NR Satellite Access Node RF Testing | Rel-19 |
| TS 38.508 vj11 | 5G NR UE Radio Transmission & Reception | Rel-19 |
| TS 38.522 vj11 | UE Conformance Test Applicability Statement | Rel-19 |
| TS 38.523 vj20 | 5G NR UE Conformance Testing: Idle/Inactive | Rel-19 |
| TS 38.774 vj00 | Rel-19 LP-WUS/WUR RF Requirements TR | Rel-19 |
| TR 38.847 vh20 | NR 47.2-48.2 GHz Frequency Range | Rel-17 |
| TR 38.849 vi50 | Technical Report | Rel-18 |
| TR 38.858 vi20 | Technical Report on Evolution of NR Duplex Operation | Rel-18 |
| TR 38.869 vi00 | Study on low-power wake up signal and receiver for NR | Rel-18 |
| TS 38.887 vg00 | NR Band n259 Specification (39.5-43.5 GHz) | Rel-16 |
| TS 51.010 vj00 | SIM Application Toolkit Conformance Testing | Rel-19 |