Description
Time Domain Channel Properties (TDCP) are parameters that describe the behavior of a wireless communication channel over time, critical for designing robust physical layer algorithms. These properties include key metrics like delay spread, which characterizes the time dispersion of multipath components, and Doppler spread, which indicates the rate of channel variation due to mobility. In 3GPP New Radio (NR), TDCP is leveraged in channel state information (CSI) reporting frameworks defined in specifications such as 38.214 and 38.331, enabling the gNB and UE to adapt transmission parameters dynamically.
The estimation of TDCP involves processing reference signals, such as Channel State Information Reference Signals (CSI-RS) or Synchronization Signal Blocks (SSBs). The UE measures the channel impulse response and power delay profile to extract delay spread, which influences choices like cyclic prefix length and equalizer design. Similarly, Doppler spread is derived from channel correlation over time, affecting mobility handling and tracking loop bandwidths. These properties are quantized and reported to the network via uplink control channels, facilitating informed scheduling and beamforming decisions.
TDCP plays a vital role in advanced NR features like beam management and massive MIMO. For instance, knowledge of delay spread helps in selecting appropriate precoding matrices and rank adaptation, while Doppler spread informs handover triggers and beam switching rates. The integration of TDCP into radio resource control (RRC) signaling allows for network-configured reporting periodicities and thresholds, balancing overhead and performance. By accurately characterizing time-domain channel variations, TDCP enhances spectral efficiency, reliability, and user experience in diverse deployment scenarios.
Purpose & Motivation
TDCP exists to provide a standardized method for quantifying time-varying channel conditions, addressing the need for adaptive physical layer techniques in modern wireless systems. It solves problems related to signal degradation in multipath and high-mobility environments, where static channel models are insufficient. The motivation stems from the increasing complexity of NR deployments, which require precise channel knowledge for features like beamforming and ultra-reliable low-latency communication (URLLC).
Historically, earlier systems like LTE included channel quality indicators but lacked detailed time-domain property reporting. TDCP in NR fills this gap by offering granular metrics that enable more sophisticated link adaptation. It addresses limitations of frequency-domain-only reporting, which may not capture temporal variations critical for mobility management. The creation of TDCP was driven by the demand for higher data rates and reliability in 5G, particularly for use cases involving fast-moving vehicles or dynamic scatterers.
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (43 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the specification introduced the 'tdmSchemeA' procedure for the Time Domain Channel Properties (TDCP) function, where a UE receives two PDSCH transmission occasions of the same transport block within a single slot. This scheme mandates that each transmission occasion is associated with a different TCI state and has a non-overlapping time domain resource allocation.
- Change Request for alignment of frequency domain resource allocation with 38.213 for a PUSCH transmission scheduled by a RAR UL grant TS 38.214CR0013
- QCL properties of Msg4 in CONNECTED Mode TS 38.214CR0020
- UE specific channel bandwidth signaling TS 38.331CR0791
- Clarification to channel bandwidth signalling TS 38.331CR0812
- Channel Bandwidth validation upon SIB1 acquisition TS 38.331CR1220
- CR to 38.331 on support of 70MHz channel bandwidth TS 38.331CR1410
In Release 16, the TDCP function was enhanced with specific procedures for handling multiple PDSCH transmission occasions within a slot, introducing distinct schemes for frequency-domain ('fdmSchemeA' and 'fdmSchemeB') and time-domain ('tdmSchemeA') multiplexing. It also defined new UE behavior for receiving PDSCH with mapping type B when scheduled by two PDCCH candidates and introduced rules for resource allocation when configured with SBFD symbols. Furthermore, corrections and clarifications were made to RSSI and channel occupancy measurements, alongside the introduction of support for BCS (Bandwidth Combination Sets) to asymmetric channel bandwidths.
- Correction on procedure for transmitting the physical sidelink shared channel TS 38.214CR0206
- Corrections on default BH RLC channel TS 38.331CR1954
- Corrections on BH RLC channel TS 38.331CR2124
- Transmission suspension on BH RLC channel upon IAB-MT failure TS 38.331CR2265
- Correction on RSSI and channel occupancy measurements TS 38.331CR2306
- Miscellaenous corrections on BH RLC channel management for IAB-MT TS 38.331CR2557
+ 1 more changes
In Release 17, the TDCP function saw specific corrections and enhancements primarily focused on time domain resource allocation procedures for operation in shared spectrum, particularly in FR2-2. These included corrections to the UE's PDSCH and PUSCH preparation procedure times for shared spectrum channel access, as well as fixes to the time domain resource allocation for PUSCH scheduled by an RAR UL grant. Furthermore, support was extended for repetition schemes on PDSCH time domain resource allocation when scheduled by DCI format 1_2.
- Simultaneous transmission of SRS and other channels for intra-band non-contiguous carrier aggregation TS 38.214CR0279
- Correction on UE PDSCH processing procedure time for operation with shared spectrum channel access in FR2-2 in TS 38.214 TS 38.214CR0299
- Correction on spatial domain filter for sensing for SRS transmission in FR2-2 TS 38.214CR0347
- Correction on UE PUSCH preparation procedure time for operation with shared spectrum channel access in FR2-2 in TS 38.214 TS 38.214CR0352
- Correction on channel measurement and interference measurement in FR2-2 in TS 38.214 TS 38.214CR0400
- Corrections to spatial domain filter determination for directional LBT in TS38.214 TS 38.214CR0420
+ 9 more changes
In Release 18, specific procedures for the TDCP function were introduced to handle collisions with other scheduled transmissions. The release included a Change Request focusing on resolving conflicts specifically between a TDCP report and a scheduled Sounding Reference Signal (SRS), ensuring reliable concurrent operation. This provides a mechanism to prevent the TDCP reporting procedure from being interrupted by or interfering with critical SRS transmissions.
- UE capability for Enhanced channel raster TS 38.331CR4445
- Introduction of new capability for intra-band EN-DC channel spacing [Intra-Band_EN-DC_Channelspacing] TS 38.331CR5013
- Corrections on RRC parameters for R18 NES spatial/power domain adaptation TS 38.214CR0544
- Correction on the highest sub-channel of PSSCH TS 38.214CR0562
- Correction of physical channels and signals during cell DTX/DRX operation TS 38.214CR0566
- Correction on IUC in co-channel coexistence case in TS 38.214 TS 38.214CR0606
+ 4 more changes
In Release 19, the new work for the Time Domain Channel Properties (TDCP) function specifically introduced a new "TDCP Report Configuration" to enhance channel state feedback. This configuration provides a framework for the UE to report detailed time-domain characteristics of the channel, which builds upon the existing physical layer procedures for PDSCH reception and resource allocation in time and frequency domains as specified in the grounding context.
- Introduction of 7MHz channel bandwidth TS 38.331CR5308
- CR on time restriction for channel measurement of UEIBM in TS 38.214 TS 38.214CR0739
- Correction on PC5 Relay RLC channel configuration TS 38.331CR5510
- CR on TDCP Report Configuration – Rel-19 TS 38.214CR0703
- Correction on QCL properties from default beam TS 38.214CR0743
Explore further
Broader topics and technologies where TDCP plays a role.
Defining Specifications
3GPP specifications that define or reference TDCP, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 38.214 vj10 | NR Physical Layer Procedures for Data | Rel-19 |
| TS 38.331 vj00 | NR Radio Resource Control (RRC) Protocol Specification | Rel-19 |