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.
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific 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.
In Release 15, the ICS (Implementation Conformance Statement) function was newly introduced with its proforma tables defined as a "For further study" item within the normative annex of the specification. This established the framework for how ICS content, when included in figures, must be prepared in accordance with the standard's formatting rules. The release also specifically added the ICS for FR2 Multiband Relaxation declaration as a new capability to be documented.
- CR to TS 38.104 Combined updates from RAN4 #90bis and RAN4#91 From RAN4 #90bis: - R4-1903105, "Draft CR to TS 38.104: Corrections on terminologies and editorial errors" - R4-1903319, "Draft CR to TS 38.104: removal of unused definition: "minimum EIRP level under extreme condition"" - R4-1903320, "Draft CR to TS 38.104: OSDD information correction" - R4-1903457, "Draft CR to TS 38.104: Removal of FFS for FR2 TDD OFF power level requirement in clause 9.5" - R4-1903499, "Draft CR to 38.104: Correction to unwanted emissions mask for bands n7 and n38" - R4-1903836, "Draft CR to TS 38.104: Correction on description on multi-band operation in section 4.8" - R4-1904024, "Draft CR to TS 38.104 Applicability rules for BS demodulation" - R4-1904234, "draftCR: Correlation matrix for 8Rx in TS 38.104" - R4-1904723, "Draft CR to TS 38.104: Update of performance requirements for DFT-s-OFDM based PUSCH" - R4-1904726, "draftCR for 38.104 on PUSCH requirements with CP-OFDM and FR1" - R4-1904729, "Draft CR on PRACH performance requirements in TS38.104" - R4-1904734, "Draft CR on TS 38.104 Performance requirement for PUCCH format 1" - R4-1904735, "Draft CR on NR PUCCH format2 performance requirements for TS 38.104" - R4-1904739, "Draft CR to TS 38.104 BS demodulation PUCCH format 0 requirements" - R4-1904745, "draftCR: Updates to PUCCH formats 3 and 4 performance requirements in TS 38.104" - R4-1904799, "Draft CR to TS 38.104: FRC update for PUSCH FR1 mapping type B and FR2 DMRS 1+1" - R4-1904816, "Draft CR : Clarification on step 5 and step 6 for delay profiles calculation (38.104)" - R4-1904842, "Draft CR to TS 38.104 BS demodulation CP-OFDM PUSCH FR2 requirements" - R4-1905126, "draft CR to 38.104 for TAE requirements" - R4-1905139, "draft CR to TS 38.104 on EVM measurement (Annex B and C)" - R4-1905140, "Draft CR: editorial correction on FR1 spurious emission requirement in TS38.104" - R4-1905143, "Draft CR for TS 38.104: Addition of NOTE for transmitter intermodulation requirements in certain regions" - R4-1905144, "Draft CR to TS 38.104: FRC reference corrections for the Rx requirements" - R4-1905145, "Draft CR to TS 38.104: Clarification on application of interfering signal offsets for ACS, blocking and intermodulation requirements" - R4-1905148, "Draft CR to TS 38.104: Corrections on out-of-band blocking requirement" From RAN4 #91: - R4-1906002, "Draft CR to 38.104: Subclause 6.7 and 9.8 transmitter intermodulation – correction of interfering signal type" - R4-1906096, "Draft CR to 38.104: Correction of frequency range for OTA spurious emissions" - R4-1906311, "Draft CR to 38.104: Correction on FRC (Annex A)" - R4-1906346, "Removal of n65 in Rel-15 38.104" - R4-1906915, "Draft CR to TS 38.104: Clarification on application of interfering signal offsets for OTA ACS, blocking and intermodulation requirements" - R4-1906918, "Draft CR to TS 38.104: Clarification on type of interfering signal for ACS, in-band blocking and ICS requirements" - R4-1907110, "Draft CR to TS 38.104: correction of the fundamental frequency limit of 2.55GHz for the spurious emissions" - R4-1907246, "Draft CR to TS 38.104: Update of performance requirements for DFT-s-OFDM based PUSCH" - R4-1907249, "Draft CR to TS 38.104: Correction on the terminology in PUSCH FRC tables" - R4-1907252, "Draft CR to TS38.104: Updates of PRACH performance requirements" - R4-1907255, "Draft CR on NR PUCCH format2 performance requirements for TS 38.104" - R4-1907258, "Draft CR on NR UCI on PUSCH performance requirements for TS 38.104" - R4-1907261, "draftCR: Updates to PUCCH formats 3 and 4 performance requirements in TS 38.104" - R4-1907266, "Draft CR on TS 38.104 Performance requirement for PUCCH format 1" - R4-1907267, "Draft CR on TS 38.104 Performance requirement for multi-slot PUCCH format 1" - R4-1907272, "Draft CR to TS 38.104 BS demodulation PUCCH format 0 requirements" - R4-1907275, "Draft CR to TS 38.104 BS demodulation CP-OFDM PUSCH FR2 requirements" - R4-1907277, "draftCR for 38.104 on PUSCH requirements with CP-OFDM and FR1" - R4-1907629, "Draft CR to 38.104: Term “reference signal” replacing by term “ideal signal” in EVM context" - R4-1907634, "Draft CR to 38.104: corrections to the EVM annex" - R4-1907659, "Draft CR to TS 38.104 on Spurious emission Category B in FR2" - R4-1907661, "Draft CR to 38.104 Definition of contiguous transmission bandwidth" - R4-1907662, "Draft CR to 38.104: BS TAE requirements" - R4-1907664, "Draft CR to 38.104: Clarification of interferer RB frequency for narrowband blocking" - R4-1907672, "Draft CR for TS 38.104: Correction on EVM" - R4-1907689, "Correction to CA carrier spacing" TS 38.104CR0029
- Addition of ICS for FR2 Multiband Relaxation declaration TS 38.508CR0036
In Release 16, the ICS function was expanded with new proforma tables and capabilities to address evolving network features. Key additions included ICS for EN-DC bands, inter-system change handling between S1 and N1 interfaces, and UE support for PUSCH Pi2 BPSK. The release also introduced ICS for iRAT RS-SINR and SFTD measurements, updated tables for specific NR bands, and refined definitions for Flexible PDU-PDN handling.
- EN-DC bands Implementation Conformance Statement (ICS) proforma Updates TS 38.508CR0054
- Update ICS proforma tables for UE implementation types in A.4.1 of 38.508-2 TS 38.508CR0078
- Adding new ICS for handling inter-system change S1-N1 and aligning PDN and PDU handling TS 38.508CR0108
- ICS for iRAT RS-SINR and SFTD measurements TS 38.508CR0110
- Addition of ICS for UE support PUSCH Pi2 BPSK TS 38.508CR0120
- Revise ICS Proforma Tables for Remaining n14, n29, and n30 Capabilities TS 38.508CR0121
+ 3 more changes
In Release 17, the ICS function was expanded to introduce new implementation conformance statements for several key capabilities and configurations. These additions specifically included ICS for NR-U (NR in Unlicensed spectrum), new power class definitions for bands n34, n39, and n79, and capabilities like UE type II PMI reporting and MMSE-IRC receiver. The release also updated the ICS baseline for various Carrier Aggregation configurations and added statements for features like Rel-17 High Speed Train enhancements and extended band definitions.
- Addition of common ICS in A.4.3.7 for Rel-16 NSSAA TS 38.508CR0183
- Introduction of ICS for NR-U TS 38.508CR0220
- Introduction of PC1.5 n79 ICS TS 38.508CR0256
- Introduction of PC2 n34 ICS TS 38.508CR0257
- Introduction of PC2 n39 ICS TS 38.508CR0258
- Addition of ICS for UE type II PMI repoering capability TS 38.508CR0271
+ 11 more changes
In Release 18, the ICS function was updated to introduce new capabilities and configurations, including common ICS proformas for Aeronautical Telecommunications (ATG) and for Power Class 1.5 (PC1.5) operations in bands like n34, n39, n40, and n41C. It added specific ICS tables for enhanced features such as DMRS, advanced MU-MIMO receivers, UL-MIMO in new bands (n13, n26, n81, n85, n105), and for RedCap UEs supporting Half Duplex FDD, while also deleting the NonCB ICS and incorporating updates for RF phase continuity tests and numerous NR band/CADC configuration statuses in Annex B.
- Addition of PC1.5 n34 and n40 ICS TS 38.508CR0516
- Deletion of NonCB ICS TS 38.508CR0517
- Update NR band and CADC configs status in ICS Annex B TS 38.508CR0550
- Addition of PC1.5 CA_n41C ICS TS 38.508CR0549
- Update NR band and CADC configs status in ICS Annex B TS 38.508CR0565
- Introduction of common ICS for ATG TS 38.508CR0563
+ 16 more changes
In Release 19, the ICS function was updated to include new carrier aggregation combinations such as CA_n5A-n29A and CA_n25A-n66A-n71A-n77A. It also introduced support for UL MIMO in band n100 and added ICS tables for High Power User Equipment (HPUE) in FR1 NR NTN bands. Furthermore, the release updated the status of various NR band and Carrier Aggregation Digital Configurations (CADC) in the normative ICS Annex B.
- Update NR band and CADC configs status in ICS Annex B TS 38.508CR0838
- ICS for CA_n5A-n29A and CA_n5A-n25A-n77(2A) TS 38.508CR0875
- ICS for CA_n25A-n66A-n71A-n77A TS 38.508CR0876
- ICS for Rel-16 FR1 intra-band CA and 2-band CA TS 38.508CR0885
- Update NR band and CADC configs status in ICS Annex B TS 38.508CR0890
- Introduction of UL MIMO band n100 for ICS TS 38.508CR0899
+ 2 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 |
