3GPP TSG RAN WG1 #121 R1-2504895
St Julian’s, Malta, May 19th – 23th, 2025
Agenda Item: 9.7
Source: Ad-Hoc Chair (Huawei)
Title: Session notes for 9.7 Study on channel modelling for Integrated Sensing And Communication (ISAC) for NR
Document for: Discussion, Decision
Study on channel modelling for Integrated Sensing And Communication (ISAC) for NR
Please refer to RP-242348 for detailed scope of the SI.
[121-R19-ISAC] Email discussion on Rel-19 ISAC channel model – Yingyang (xiaomi)
To be used for sharing updates on online/offline schedule, details on what is to be discussed in online/offline sessions, tdoc number of the moderator summary for online session, etc
R1-2504160 Draft CR for TR 38.901 to introduce channel model for ISAC Xiaomi, AT&T
[Post-121-ISAC-01] – Yingyang (Xiaomi)
Email discussion for endorsement of CR for TR38.901 update to introduce ISAC channel model, for submission to RAN plenary, from May 26 to May 30.
[Post-121-ISAC-02] – Jerome (AT&T)
Email discussion for collection of calibration results for the ISAC channel model, in 3 phases:
For updating results for large scale calibration: Until August 1
For full calibration results: Until August 21
For additional feature calibration: Until August 21
Companies can decide which option(s) to calibrate for those additional features with multiple options
Rapporteur will provide separate excel templates for different options
ISAC deployment scenarios
Please provide your inputs on calibrations is to this sub-agenda item.
R1-2503247 Deployment scenarios for ISAC channel model Huawei, HiSilicon
R1-2503372 Views on Rel-19 ISAC deployment scenarios vivo
R1-2503445 Discussion on ISAC deployment scenarios and requirements EURECOM
R1-2503576 Discussion on ISAC deployment scenarios Samsung
R1-2503697 Discussion on ISAC deployment scenarios ZTE Corporation, Sanechips, CAICT
R1-2503752 Discussion on ISAC deployment scenarios InterDigital, Inc.
R1-2503760 Discussion on ISAC Deployment Scenarios SK Telecom
R1-2503803 Discussion on ISAC deployment scenarios CATT, CICTCI
R1-2503841 Discussion on full calibration of ISAC channel model CMCC
R1-2503858 Discussion on ISAC channel calibration BUPT, CMCC, X-Net
R1-2503892 Scenario and calibration discussion for ISAC CM Xiaomi
R1-2503954 Discussion on ISAC Deployment Scenarios Nokia, Nokia Shanghai Bell
R1-2503967 Discussion on ISAC deployment scenarios Tiami Networks
R1-2503992 Deployment scenarios for integrated sensing and communication with NR NVIDIA
R1-2504012 Discussion on ISAC Deployment Scenarios NIST
R1-2504053 Discussion on ISAC deployment scenarios China Telecom
R1-2504068 Remaining issues on ISAC deployment scenarios Sony
R1-2504126 Discussion on ISAC deployment scenarios CALTTA
R1-2504146 Discussion on calibration results ETRI
Late submission
R1-2504220 Discussion on ISAC channel model calibration OPPO
R1-2504239 Discussion on ISAC deployment scenarios Lenovo
R1-2504268 Discussion on ISAC deployment scenario MediaTek Inc.
R1-2504336 Discussion on ISAC deployment scenarios and Calibration Apple
R1-2504367 ISAC scenarios and 7-24GHz alignment AT&T, FirstNet
R1-2504404 Discussion on ISAC deployment scenarios Qualcomm Incorporated
R1-2504454 Discussion on ISAC Deployment Scenarios Ericsson
R1-2504539 Discussion of calibration for UAV sensing targets ITRI, Tron Future Tech Inc.
R1-2504566 Discussion on ISAC deployment scenarios LG Electronics
R1-2504363 FL Summary #1 on ISAC Scenarios and Calibrations Moderator (AT&T)
Agreement
Updates to Table 7.9.1-1: Evaluation parameters for UAV sensing scenarios are as follows:
NOTE: A percentage of TRPs/UEs that have sensing capabilities may be considered for future evaluations.
Conclusion
Channel model for ISAC for SMa scenario will not be fully studied in Rel-19.
Agreement
Updates to Table 7.9.1-2: Evaluation parameters for Automotive sensing scenarios are as follows:
NOTE1: calibration for UMi, , RMa can be considered for future evaluations of the automotive sensing target scenarios.
NOTE2: A percentage of TRPs/UEs that have sensing capabilities may be considered for future evaluations.
Agreement
Updates to Table 7.9.1-3: Evaluation parameters for Human (indoor and outdoor) sensing scenarios as follows:
Agreement
Updates to Table 7.9.1-4: Evaluation parameters for Automated Guided Vehicles sensing scenarios as follows:
Agreement
Updates to Table 7.9.1-5: Evaluation parameters for objects creating hazards sensing scenarios as follows:
Agreement
Updates to Table 7.9.7.1-3. Simulation assumptions for large scale calibration for Automotive sensing targets as follows:
Agreement
Clarification for metrics for Simulation assumptions for full calibration sensing targets as follows:
Agreement
Updates to Table 7.9.7.2-2: Simulation assumptions for full calibration for Human sensing targets as follows:
Agreement
The following introductory text is added before each of the ISAC deployment scenarios;
ISAC-UAV
In the ISAC-UAV scenario, the sensing targets are outdoor UAVs below or above the buildings in urban or rural areas. Monostatic or bistatic sensing can be performed using TRPs and/or UEs, including UEs on other UAVs.
ISAC-Automotive
In the ISAC-Automotive scenario, the sensing targets are passenger vehicles or trucks and buses traveling on roads and streets in urban and rural areas. Monostatic or bistatic sensing can be performed using TRPs and/or UEs, including UEs on other vehicles and roadside UEs (RSU-type UEs).
ISAC-Human
In the ISAC-Human scenario, the sensing targets are children and adult persons in indoor (room, office, factory) and outdoor (urban, rural) locations. Monostatic or bistatic sensing can be performed using TRPs and/or UEs in the corresponding communication scenarios.
ISAC-AGV
In the ISAC-AGV scenario, the sensing targets are automated guided vehicles (AGVs) inside a factory. Monostatic or bistatic sensing can be performed using TRPs and/or UEs in the corresponding communication scenario.
ISAC-Objects creating hazards
In the ISAC-Objects creating hazards scenario, the sensing targets are adult humans and children and animals in communication scenarios involving vehicles or high-speed trains. Monostatic or bistatic sensing can be performed using TRPs and/or UEs, including UEs on other vehicles and roadside UEs (RSU-type UEs).
Agreement
Updates to 7.9.7.1-4: Simulation assumptions for large scale calibration for AGV sensing targets as follows:
Agreement
Updates to 7.9.7.2-4: Simulation assumptions for full calibration for AGV sensing targets as follows:
R1-2504364 FL Summary #2 on ISAC Scenarios and Calibrations Moderator (AT&T)
Agreement
Resolve square brackets for Table 7.9.1-4: Evaluation parameters for Automated Guided Vehicles sensing scenarios:
R1-2504365 FL Summary #3 on ISAC Scenarios and Calibrations Moderator (AT&T)
R1-2504366 FL Summary #4 on ISAC Scenarios and Calibrations Moderator (AT&T)
ISAC channel modelling
R1-2503248 Channel modelling for ISAC Huawei, HiSilicon
R1-2503373 Views on Rel-19 ISAC channel modelling vivo, BUPT
R1-2503446 Discussion on ISAC channel modeling EURECOM
R1-2503525 Discussion on ISAC channel modeling Spreadtrum, UNISOC
R1-2503577 Discussion on ISAC channel modelling Samsung
R1-2503646 Discussion on ISAC channel modelling Pengcheng Laboratory
R1-2503698 Discussion on channel modelling for ISAC ZTE Corporation, Sanechips, CAICT
R1-2503720 Discussion on ISAC channel modelling Tejas Network Limited
R1-2503726 Discussion on ISAC channel modelling TOYOTA InfoTechnology Center
R1-2503753 Discussion on ISAC channel modeling InterDigital, Inc.
R1-2503761 Discussion on ISAC Channel Modeling SK Telecom
R1-2503804 Discussion on ISAC channel modelling CATT, CICTCI
R1-2503842 Discussion on ISAC channel modeling CMCC
R1-2503859 ISAC Channel Modeling and Measurement Validation BUPT, CMCC, VIVO, X-Net
R1-2503893 Discussion on ISAC channel model Xiaomi, BJTU, BUPT
R1-2503955 Discussion on ISAC channel modeling Nokia, Nokia Shanghai Bell
R1-2503969 Discussion on ISAC Channel Modeling Tiami Networks
R1-2503991 Channel modelling for integrated sensing and communication with NR NVIDIA
R1-2504013 Discussion on ISAC Channel Modeling NIST
R1-2504054 Discussion on ISAC channel modelling China Telecom
R1-2504069 Remaining issues on ISAC Channel Modeling Sony
R1-2504110 Discussion on ISAC Channel Modelling Panasonic
R1-2504119 Discussion on channel modelling for ISAC CALTTA
R1-2504159 Discussion on ISAC channel modelling Pengcheng Laboratory
R1-2504221 Study on ISAC channel modelling OPPO
R1-2504240 Discussion on Channel Modelling for ISAC Lenovo
R1-2504269 Discussion on ISAC channel modelling MediaTek Inc.
R1-2504337 Discussion on ISAC channel modelling Apple
R1-2504405 Discussion on ISAC channel modelling Qualcomm Incorporated
R1-2504455 Discussion on ISAC Channel Modelling Ericsson
R1-2504511 Discussion on ISAC Channel Modelling NTT DOCOMO, INC.
R1-2504567 Discussion on ISAC channel modelling LG Electronics
R1-2504161 Summary #1 on ISAC channel modelling Moderator (Xiaomi)
R1-2504162 Summary #2 on ISAC channel modelling Moderator (Xiaomi)
Agreement
Confirm the following working assumption with updates in red.
Working assumption
For vehicle with single/multiple scattering points, the bistatic RCS is generated by
The values/pattern of A*B1 of bistatic RCS is given by:
where
is applied to the within 0~180 degrees. k1= 6 and k2=1.65. is the bistatic angle between the incident ray and scattering ray within the plane of incident direction () and scattering direction ().
The angles of () are the projections of the bisector angle on the vertical plane and the horizontal plane, respectively.
FFS: RCS value when is 180 degrees
The effect of forward scattering is -Inf in Rel-19
5 sets of parameters Applicable Range of and Applicable Range of are applicable as defined for the monostatic RCS of vehicle with single/multiple SPSTs
Continue study on a new formula for to resolve the issue of angular discontinuity.
The new formula should retain following property: the linear bistatic RCS for a vehicle with single scattering point is the sum of the bistatic RCS of the multiple scattering points of the vehicle
the following formula can be a reference for the study
Agreement
The agreement on bistatic RCS for vehicle is reused for large size UAV and AGV.
For large size UAV, k₁=6.05 and k₂=1.33
For AGV, k₁=12 and k₂=1.45
Agreement
AGV can be modelled with multiple scattering points.
The values/pattern of component A*B1 are generated by the following parameters
Note: For the scattering point associated with roof of the AGV, .
Note: the measurements from companies are done by AGV option 1.
Agreement
The bistatic RCS of UAV with small size is modelled as
The values/pattern of A*B1 is given by
Component A, i.e., : same as component A of mono-static RCS for UAV of small size
dB, where is the bi-static angle between incident ray and scattered ray, is within 0 and 180 degree
The effect of forward scattering is -Inf in Rel-19
Component B2: same as component B2 of mono-static RCS for UAV of small size
The bistatic RCS of Human with RCS model 1 is modelled as
The values/pattern of A*B1 is given by
Component A, i.e., : same as component A of mono-static RCS for Human with RCS model 1
dB, where is the bi-static angle between incident ray and scattered ray, is within 0 and 180 degree
The effect of forward scattering is -Inf in Rel-19
Component B2: same as component B2 of mono-static RCS for Human with RCS model 1
Agreement
On the monostatic RCS of human with RCS model 2,
The values/pattern of component A*B1 are generated by the following parameters
The standard deviation of component B2 is 3.94 dB
Agreement
The agreement on bistatic RCS for vehicle with single scattering point is reused to model bistatic RCS of human with RCS model 2
k1=0.5714 and k2=0.1
Agreement
The following values of the RCS component A are applied to both monostatic and bistatic RCS of the target.
UAV with large size: -5.85 dBsm
Human with RCS model 2: -1.37 dBsm
Note: measurement is based on adult
Vehicle: 11.25 dBsm
Note: measurement is based on vehicle type 1 and 2
AGV: -4.25 dBsm
Note: measurement is based on AGV option 1
Note: component A on its own may not fully reflect the RCS in the target channel. This note will not be captured in the TR.
Agreement
The mean and standard deviation values of XPR of sensing target AGV for monostatic sensing and bistatic sensing are (9.60, 6.85) dB.
Conclusion
The component B2 of two different targets are generated independently.
Conclusion
The component XPR/initial random phase of two different targets are generated independently.
Agreement
In order to generate Tx-target link, target-Rx link and the background channel between a RSU-type UE and another node (TRP, pedestrian UE, vehicle UE, RSU-type UE), the following reference TRs are adopted
Agreement
The initial random phase (generated in Step 10, section 7.5, TR38.901) is the same for the same ray in Tx-target link and target-Rx link of a target for monostatic sensing.
Agreement
For UMi-AV and RMa-AV with aerial UE as sensing transmitter or receiver, the values of parameters to generate background channel for UT monostatic sensing are provided in the following table
Note 1: Distributions of height and distance of reference point are not subject to geographical constraints on TRP for the corresponding deployment scenario.
Note 2: The reference points for generating the UT monostatic background channel have the same velocity as UT.
Note 3: In the UT monostatic sensing in UMa and UMi scenario, the ZOD offset in the background channel should be set as 0
Agreement
To generate the background channel for TRP monostatic sensing and UT monostatic sensing, ‘ +’ is used to model the absolute delay between the Tx and each reference point.
Agreement
Power threshold for path dropping after concatenation is up to -40dB for target channel for option 3. Up to company to choose a value in the implementation.
Power threshold for path dropping after concatenation is up to -25dB for target channel for option 0. Up to company to choose a value in the implementation.
For calibrations for both option 0 and option 3, power threshold for path dropping after concatenation is -40dB for target channel.
Agreement
To generate the absolute delay model for sensing scenarios Urban grid, highway and HST, for both target channel and background channel
For Urban grid, the values of parameters for of scenarios UMa are reused.
For Highway, the values of parameters for of scenarios RMa and UMa are reused for FR1 and FR2 respectively.
For HST, the values of parameters for of scenarios RMa and UMa are reused for FR1 and FR2 respectively.
Note: no measurements on of the 3 scenarios are submitted in Rel-19.
Agreement
Spatial consistency is not modelled for
the links that are generated referring to channel models with parameter values of different communication scenarios
E.g., between TRP-target/UT link in one scenario and target/UT-UT link in another scenario
the background channels for TRP monostatic sensing of different TRPs
Agreement
Spatial consistency is not modelled between TRP-target/UT link and target/UT-UT link for sensing scenario UMi, InH and InF.
Agreement
Spatial consistency is not modelled between TRP-TRP link and any other links for ISAC channel.
Agreement
Spatial consistency can be enabled for multiple scattering points of a target.
Spatial consistency, if enabled, for the links between BS/UT and multiple scattering points of a target are modelled as if multiple scattering points are multiple targets.
Agreement
The existing horizontal correlation distance in Table 7.6.3.1-2 in TR38.901 is used as the correlation distance for 3D spatial consistency for ISAC channel at least for UAV scenario, within same ‘Applicability range in terms of aerial UE height (defined in 36.777)’.
Agreement
EO type-2 can be modelled in NLOS condition.
Agreement
In sensing scenario UMi, UMa, if the height of a scattering point of target is less than 1.5m, for pathloss calculation,
use hUT 1.5 m for breakpoint distance (dBP) calculation
Note: hUT 1.5 m is only used for dBP calculation. The exact h_UT of the scattering point is still used to determine all other parameters of ISAC channel, e.g., delay, AOD/ZOD/AOA/ZOA, etc.
Agreement
On background channel modelling,
Spatial consistency is not supported for TRP monostatic sensing across different TRPs
Spatial consistency is not supported for UE monostatic sensing across different UEs
Spatial consistency is not supported across different Reference Points for same TRP for TRP monostatic sensing
Spatial consistency is not supported across different Reference Points for same UE for UE monostatic sensing
Agreement
RCS component B2 of different direct/indirect paths of a target in the target channel are generated independently.
On the RCS component B2 of a direct/indirect path of a target in the target channel, the same value of B2 applies to a path before the value of B2 is updated.
Note: whether/how/when to update B2 can be discussed in evaluation phase or up to companies’ choices
Agreement
XPR of different direct/indirect paths of a target in the target channel are generated independently.
On the XPR of a direct/indirect path of a target in the target channel, the same value of XPR applies to a path before the value of XPR is updated.
Note: whether/how/when to update XPR can be discussed in evaluation phase or up to companies’ choices
Agreement
Initial random phase of different direct/indirect paths of a target in the target channel are generated independently.
On the initial random phase of a direct/indirect path of a target in the target channel, the same value of initial random phase applies to a path before the value of initial random phase is updated.
Note: whether/how/when to update initial random phase can be discussed in evaluation phase or up to companies’ choices
R1-2504163 Summary #3 on ISAC channel modelling Moderator (Xiaomi)
Agreement
The follow TP is used generate the power (except for the impact of polarization matrix of EO type-2) of the ray specular reflected by an EO type 2 in the STX-SPST link or SPST-SRX link.
Agreement
To generate the absolute delay model for sensing scenarios UMi-AV, UMa-AV and RMa-AV, for both target channel and background channel,
For the TRP-TRP link and TRP- terrestrial UE link, the values of parameters for of scenarios UMi, UMa and RMa are respectively reused.
For the terrestrial UE- terrestrial UE link, the values of parameters for of scenarios UMi are reused.
For the TRP- aerial UE link, the values of parameters for of scenarios UMi, UMa and RMa are respectively reused.
For the terrestrial UE- aerial UE link, the values of parameters for of scenarios UMi are reused.
For the aerial UE- aerial UE link, the values of parameters for of scenarios UMi are reused.
Note: no measurements on of the scenarios UMi-AV, UMa-AV and RMa-AV are submitted in Rel-19.
Agreement
Remove the brackets for first sub-bullet under Step 4 for Clause 7.9.4.2 in the CR to TR 38.901.
On the absolute delay of the background channel for both TRP and UE monostatic sensing, three are independently generated and respectively applied to the 3 channels between the STX/SRX and the 3 RPs.
Agreement
To generate the channel between an aerial UE and a normal UE,
The LOS probability is generated by:
The pathloss and shadow fading are generated using TRP-aerial UE link of UMi-AV in Annex A and B of TR 36.777 by setting hBS =1.5m for FR1
Note:
The height ranges of low-UAV, Mid-UAV and High-UAV are defined following the applicability range in terms of aerial UE height in Table B-1: LOS probability in TR 36.777
The second height range for UMi-AV is further divided into 2 regions, i.e., [22.5, 100] and [100, 300] for mid-UAV and high-UAV, respectively.
Conclusion
No further study on power normalization of target channel and background channel of ISAC channel in Rel-19
Note: sub-section “7.9.5.3 Power normalization across target channel and background channel” in the TR remains as a placeholder with the following text.
To combine the target channel and the background channel, power normalization can be applied to keep the same/similar channel power as the background channel without sensing target.
Agreement
The polarization matrix of a direct/indirect path i of a scattering point of a target is defined in LCS.
Agreement
To generate the channel between a first aerial UE with height h1 and a second aerial UE with height h2, abs(h1-hBS) <= abs(h2-hBS),
The LOS probability between the two aerial UEs is generated by:
The pathloss and shadow fading between two aerial UEs are generated using TRP-aerial UE link of UMi-AV in Annex A and B of TR 36.777 by setting height of TRP equal to the height of the first aerial UE.
Note:
The height ranges of low-UAV, Mid-UAV and High-UAV are defined following the applicability range in terms of aerial UE height in Table B-1: LOS probability in TR 36.777
The second height range for UMi-AV is further divided into 2 regions, i.e., [22.5, 100] and [100, 300] for mid-UAV and high-UAV, respectively.
R1-2504164 Summary #4 on ISAC channel modelling Moderator (Xiaomi)
Agreement
Update the agreements on LOS probability calculation for channel between an aerial UE and a normal UE as follows.
Agreement
Update the agreements on LOS probability calculation for channel between two aerial UE as follows.
Agreement
To determine the LOS condition of any link in ISAC channel model, when EO type-2 is modelled, the following two options are agreed as solutions:
Option A: If type-2 EO is in the LOS ray of the link, the LOS probability is p, p=0, and otherwise use the LOS probability equation defined in existing TRs to determine the LOS/NLOS condition
Option C: Use the LOS probability equation to determine the LOS/NLOS condition of the link.
Note1: in which conditions/scenarios to use option A or option C can be determined in future evaluations.
Note2: as already agreed, monostatic background channel is always NLOS
Agreement
EO type-2 can be optionally modelled in background channel when EO type-2 is modelled in target channel.
Conclusion
Delete subsection 7.9.6 from the draft CR. For ISAC, no enhancement to LLS channel model is introduced in Rel-19.
Conclusion
Other than RCS for human, vehicle, AGV, UAV, no other RCS for other objects is introduced in Rel-19.
Future studies are not precluded for adding RCS of other objects/sizes for modelling target or EO type-1, based on validation results from companies.
R1-2504165 Summary #5 on ISAC channel modelling Moderator (Xiaomi)
Conclusion
Delete subsection 7.9.6 from the draft CR. For ISAC, no enhancement to existing TR38.901 LLS channel model is introduced in Rel-19.
Agreement
The existing blockage model A/B procedures can be reused to model the blocking effect due to a target as an optional feature
Applicable to the LOS/NLOS rays in the background channel of the target
Applicable to the LOS/NLOS rays in the Tx-target and target-Rx link of another target
The location, orientation and size of the target as a blocker is known before applying the blockage model A/B.
Agreement
The square brackets on formula 7.9.5-10 (copied below) in the draft CR are removed
The effective polarization matrix of the type-2 EO reflection path is given by
[ (7.9.5-10)]
Encourage companies to check and compare with the results that can be obtained with Alt2 and Alt3 below. If problem is found, RAN1 will revise TR 38.901 by new CR.
Alt2
[ (7.9.5-10)]
With reusing the legacy transformation method for deriving and .
Alt3
[ (7.9.5-10)]
Where,
- . represents the normal vector of the incident plane. , in which and . represents the spherical basis vector of incident ray in vertical direction. represents the spherical basis vector of incident ray in horizontal direction. .
- . represents the polar basis vector of scattering ray in vertical direction. represents the polar basis vector of scattering ray in horizontal direction. . .
Conclusion
There is no consensus to introduce an exact formula for micro-Doppler in Rel-19. The placeholder in the channel impulse response is kept in the draft CR.
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