Enhancements in interference reporting in 5g NR systems

Abstract

A system and a method for Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI) between Layer 2 (L2) and Layer 1 (L1) cloud-based Radio Access Networks (RAN) related to enhancements in interference and noise measurement and reporting between L1 and L2 modules, which may be incorporated in SCF-FAPI improving system performance.

Description

ENHANCEMENTS IN INTERFERENCE REPORTING IN 5G NR SYSTEMSBACKGROUND1. Field of the Disclosure

[0001] The present disclosure is related to procedures and messages exchanged in Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI) between Layer 2 (L2) and Layer 1 (LI) cloud-based Radio Access Networks (RAN). More particularly, the present disclosure is related to enhancements in interference and noise measurement and reporting between LI and L2 modules, which may be incorporated in SCF-FAPI improving system performance.2. Description of Related Art

[0002] Radio Access Networks (RAN) have been in use for many years and have become an integral part of daily life for many people around the world. With millions of people utilizing RANs, the amount of information and data that is uploaded and downloaded between the RAN and User Equipment (UE) is enormous and continues to increase year by year. As data volume increases and more UE access RANs, problems relating to interference in the RAN have significantly grown.

[0003] Interference reporting is provided in reporting formats for the Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control Channel (PUCCH) channels. The current 5G Functional Application Platform Interface (FAPI) Physical Layer API Specification supports Signal to Noise Ratio (SNR) reporting in a “CRC Indication” message as explained in the call flow in FIG. 1.

[0004] Uplink Signal to Noise Ratio Metric (UL-SINR-Metric) is parameter in Cyclic Redundancy Check (CRC) Indication message to report UpLink (UL) measured Interference and Noise. The UL-SINR-Metric seen from the above report is calculated considering the DeModulation Reference Signal (DMRS) symbols present in the resource grid. DMRS reference signals occupy certain symbols. As per 3rd Generation Partnership Project (3GPP) specifications, it can be 1, 2, 3 or 4 reference symbols in a slot. The existing SCF-FAPI specification measures the interference and noise as a whole and reports to upper layers.However, there is no provision for specifying any specific DMRS symbol(s) for which the interference and noise to be measured and reported is assigned.

[0005] The location of DMRS symbols in PUSCH slot in a UL Frame is shown in FIG. 2. In the case of 4 DMRS symbol allocation, the symbol locations are in the symbol index 2, 6, 9 and 13. The current method of measuring the interference considers all the DMRS resources across all the symbols in a slot. The number of DMRS resources in a slot depends on the configurations, which will be reported to User Equipment (UE) in a Radio Resource Control (RRC) message. The minimum number of DMRS symbols in a slot is 1, and a maximum of 4 symbols can be configured, which depends on length of PUSCH allocated symbols. The density and size of DMRS symbols can be adjusted based on the configurations.

[0006] The structure of CRC Indication message carrying the parameter UL-SINR-Metric is shown in FIG. 3.

[0007] Interference reporting in PUSCH - UCI Indication message. Like the above condition of PUSCH, when Uplink Control Information (UCI) bits are multiplexed with PUSCH, PUSCH can carry Hybrid Automatic Repeat Request (HARQ) Feedback, Scheduling Request(SR) and CSI (Channel State information) reports. In such scenarios LI would report UCI Indication to L2 containing the measurement related to interference and noise along with a CRC indication message, which is illustrated in FIG. 4.

[0008] Interference reporting in PUCCH PDU - UCI indication message. Interference and Noise measurement in PUCCH resources also happens on all the symbols and resources on the PUCCH allocated Resource Element (Res). FIG. 5 illustrates UCI indication message call flow in FAPI, and the frame structure with PUCCH Packet Data Unit (PDU) with DMRS symbols is shown in FIG. 6. The proposed method is applicable to PUCCH long formats such as PUCCH Format 1 (Fl) and PUCCH Format 3 (F3). The reference symbol pattern may be different as per the configurations.

[0009] UCI indication is the report sent from LI to L2. This contains reports such as HARQ Feedback, SR, and CSI reports, that are carried in PUCCH. The layout of UCI Indication having PUCCH PDU is shown in FIG. 7.

[0010] With the current approach of interference and noise measurement done at LI, there is little clarity on how LI must compute these statistics. It is left to LI implementation to measure the interference and report it back, upon the request from L2. This is challenging in L2 implementations, particularly when L2 is integrated with different LI vendors that employ different methodologies for interference and noise measurement.

[0011] Additionally, in Ducting interference cases with remote Next Gen Node B (gNB) causing interference to the native gNB, the interference levels at L2 must be known on a per symbol or per measurement symbol basis to apply certain mitigation techniques.

[0012] The existing methods in FAPI are not suitable for such scenarios and need enhancements in interference reporting. There is no mechanism in the existing FAPI interface for per symbol level reporting of interference on the allocated PRBs.

[0013] Accordingly, there is a need for methodology that overcomes, alleviates, and / or mitigates one or more of the aforementioned and other deleterious effects of prior art relating to interference measurement and reporting.SUMMARY

[0014] The present disclosure provides a system and a method to enhance the interference measurement and reporting procedures between L2-L1 modules that can be used in SCF-FAPI standards.

[0015] It is further desired to provide a system and a method to enhance the interference measurement and reporting procedures in cloud-based RANs where L2 and LI processing is performed in a Distributed Unit (DU).

[0016] It is also desired to provide a system and a method to enhance the interference measurement and reporting procedures in cloud-based RANs where L2 processing is performed in a DU and LI processing is performed in a Radio Unit (RU).

[0017] The proposed changes will be helpful for better handling of interference scenarios in thereby overall system performance can be improved.

[0018] In one configuration, a system is provided in the field of cloud-based Radio Access Networks (RANs) where L2 and LI processing is performed in a DU, or alternatively, where L2is hosted in a DU and LI is hosted in an RU where SCF-FAPT is the standardized interface between L2 and LI.

[0019] Additionally, in another configuration for interference measurement and reporting, L2 accurately conveys the methodology for LI in measuring the interference and reporting to upper layers. This is done based on capability of LI module by considering different averaging techniques

[0020] Still further, in yet another configuration for interference measurement and reporting, per symbol-wise interference reporting is accomplished on the allocated Physical Resource Blocks (PRBs). In scenarios like Remote or Ducting interference due to a remote gNB, the severity of interference must be measured on a per Symbol basis on the UL slots. This will enable adjustment of the Start and Length Indicator Value (SLIV) of Physical Data Shared Channel (PDSCH) scheduling to minimize interference.

[0021] For this application the following terms and definitions shall apply:

[0022] The term “data” as used herein means any indicia, signals, marks, symbols, domains, symbol sets, representations, and any other physical form or forms representing information, whether permanent or temporary, whether visible, audible, acoustic, electric, magnetic, electromagnetic or otherwise manifested. The term “data” as used to represent predetermined information in one physical form shall be deemed to encompass any and all representations of the same predetermined information in a different physical form or forms.

[0023] The term “network” as used herein includes both networks and internetworks of all kinds, including the Internet, and is not limited to any particular type of network or inter-network.

[0024] The terms “coupled”, “coupled to”, “coupled with”, “connected”, “connected to”, and “connected with” as used herein each mean a relationship between or among two or more devices, apparatus, fdes, programs, applications, media, components, networks, systems, subsystems, and / or means, constituting any one or more of (a) a connection, whether direct or through one or more other devices, apparatus, files, programs, applications, media, components, networks, systems, subsystems, or means, (b) a communications relationship, whether direct or through one or more other devices, apparatus, files, programs, applications, media, components, networks, systems, subsystems, or means, and / or (c) a functional relationship in which the operation of any one or more devices, apparatus, files, programs, applications, media, components, networks, systems, subsystems, or means depends, in whole or in part, on the operation of any one or more others thereof.

[0025] As used herein, the phrases "at least one" ,"one or more" ,"or" and "and / or" are open- ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B and C" ,"at least one of A, B, or C", "one or more of A, B, and C", "one or more of A, B, or C," "A, B, and / or C" and "A, B, or C" means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

[0026] In one configuration, a cloud-based Radio Access Network (RAN) utilizing Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI) is provided, the RAN comprising: a Centralized Unit (CU), a Distributed Unit (DU) coupled to the CU, and a plurality of Radio Units (RU) having one or more sectors, the plurality of Rus coupled to the DU where each RU is adapted to have a plurality of User Equipment (UE) coupled to each RU. The RAN is provided such that Layer 1 (LI) and Layer 2 (L2) processing is performed in the DU, or a LI module is hosted in a respective RU and a L2 module is hosted in the DU. The RAN is furtherprovided so that remote gNodeB (gNB) interference is measured, and the measured interference is reported using SCF-FAPI from LI to L2 to improve system performance, and LI is used to report a measurement methodology of LI to upper layers.

[0027] In another configuration, a method for measuring interference in cloud-based Radio Access Network (RAN) utilizing Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI) having a Centralized Unit (CU) coupled to a Distributed Unit (DU) and a plurality of Radio Units (RUs) each having one or more sectors, the plurality of RUs coupled to the DU where each RU is adapted to have a plurality of User Equipment (UE) coupled to each RU is provided, the method comprising the steps of performing Layer 1 (LI) and Layer 2 (L2) processing in the DU, or hosting a LI module in a respective RU and hosting a L2 module in the DU. The method further comprises the steps of measuring remote gNodeB (gNB) interference and reporting the measured interference using SCF-FAPI from LI to L2 to improve system performance, where LI is used to report a measurement methodology of LI to upper layers.

[0028] The above-described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is a functional flow diagram illustrating Interference reporting through CRC Indication message according to the prior art.

[0030] FIG. 2 is a diagram illustrating PUSCH DMRS locations in a slot according to the prior art.

[0031] FIG. 3 is a functional flow diagram illustrating CRC Indication Layout according to the prior art.

[0032] FIG. 4 is a functional flow diagram illustrating UCI Indication in PUSCH according to the prior art.

[0033] FIG. 5 is a functional flow diagram illustrating UCI INDICATION for PUCCH PDU according to the prior art.

[0034] FIG. 6 is a diagram illustrating PUCCH Long format - Format 1 and Format 3 DMRS Pattern according to the prior art.

[0035] FIG. 7 is a functional flow diagram illustrating UCI indication in PUCCH PDU according to the prior art.

[0036] FIG. 8 is a functional flow diagram illustrating Capability Inquiry and Configuration call flow according to one configuration of the invention.

[0037] FIG. 9 is a functional flow diagram illustrating UL.TTI Request, Interference and Noise measurement and reporting according to the configuration of FIG. 8.

[0038] FIG. 10 is a table including descriptions for parameters newly added in PUSCH PDU of UL TTI Request according to the configuration of FIG. 9.

[0039] FIG. 11 is a table including descriptions for parameters newly added in PUCCH PDU of UL TTI Request.

[0040] FIG. 12 is a table including descriptions for parameters newly added in CRC Indication.

[0041] FIG. 13 is a table including descriptions for parameters newly added in PUCCH format 0 / 1 in UCI Indication.

[0042] FIG. 14 is a table including descriptions for parameters newly added in PUCCH format 2 / 3 / 4 in UCI Indication.DETAILED DESCRIPTION

[0043] Referring to the drawings and in particular to FIG. 8, a methodology for interference measurement and reporting is provided. The new methodology for interference and measurement reporting is described in two steps with the additional parameters in the FAPI interfaces.

[0044] Capability Enquiry Phase: L2 understands the LI capability about one of the predefined Interference measurements methodologies. It is about averaging method for interference measurement and reporting. This happens using Param. Request and Param. Response messages in P5 interface. This is explained in FIG. 6. There is an option to configure the no averaging as well.

[0045] Configuration Phase: Depending on the LI capability, L2 would configure the methodology for interference and noise measurement and reporting in message. The additional parameters for averaging are also configured in this phase. This is explained in the below figures.

[0046] In the existing call flow as explained in FIG. 8 the new additions are:1) Methodology reporting by LI to L2 in Param response.2) Methodology to report instructed by L2 to LI in config. request.

[0047] The additional parameters or call flows are highlighted below. The details of the message structure are further described.

[0048] Param.Request - There is no change in this message.

[0049] Param.Response - The below table explains the Tag Length Values (TLV) sent from LI to L2 as part of the Param.Response message. Measurement Param TLV would be added with the new parameters to reflect the capability of LI in employing the methodology of interference and noise measurement.

[0050] Note: For simplicity and ease of reading, only the modified / added fields are explained in all the messages / parameters below.Measurement ParamTable 1

[0051] Note: The TAG ids would be decided during the SCF FAPI forum discussions.Config Request (From L2 to LI)Measurement configTable 2

[0052] Referring now to FIG. 9, per symbol-wise interference reporting on the allocated PRBs is illustrated. This call-flow explains how UL TTI Request can be used by L2 to indicate which specific DMRS symbol(s) are of interest to measure the interference and noise from LI perspective. It further explains how LI reports such Interference and Noise specific to a set of DMRS symbols.

[0053] Two new fields are added to PUSCH PDU inside UL.TTI Request. Additionalparameters for PUSCH PDU are given in FIG. 9.

[0054] The following steps are proposed to obtain per DMRS symbol Interference and Noise estimation in L2 module.

[0055] PUSCH PDU L2 requests a specific set of DMRS symbols for interference measurement. This is sent in “PUSCH PDU” contained in UL-TTI.Request. This is explained in FIG. 10.

[0056] LI measures the interference only on those symbols and reports the interference measurement on those symbols (refer to FIG. 12). The PUSCH PDU mentioned in connection with FIG. 12, is specific to a UE, notified by a Radio Network Temporary Identifier (RNTI) field, which is an existing field.

[0057] PUCCH PDU: L2 requests a specific set of DMRS symbols for interference measurement. This is sent in “PUCCH PDU” contained in UL-TTI.Request. This is explained in FIG. 11. Note: The PUCCH PDU mentioned in connection with FIG. 11, is specific to a UE, notified by an RNTI field, which is an existing field.

[0058] LI measures the interference only on those symbols and reports the interference measurement (refer to FIGS. 13 & 14). FIG. 13 is PUCCH Format 0 / 1 of UCI Indication. FIG. 14 is PUCCH Format 2 / 3 / 4 of UCI Indication.

[0059] While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications can be made to adapt a particular situationor material to the teachings of the disclosure without departing from the scope thereof.Therefore, it is intended that the present disclosure not be limited to the particular embodiment s) disclosed as the best mode contemplated, but that the disclosure will include all embodiments falling within the scope of the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A cloud-based Radio Access Network (RAN) utilizing Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI), the RAN comprising: a Centralized Unit (CU); a Distributed Unit (DU) coupled to the CU; and a plurality of Radio Units (RU) having one or more sectors, the plurality of Rus coupled to the DU where each RU is adapted to have a plurality of User Equipment (UE) coupled to each RU; wherein Layer 1 (LI) and Layer 2 (L2) processing is performed in the DU, or a LI module is hosted in a respective RU and a L2 module is hosted in the DU; wherein remote gNodeB (gNB) interference is measured; and wherein the measured interference is reported using SCF-FAPI from LI to L2 to improve system performance, and LI is used to report a measurement methodology of LI to upper layers.

2. The RAN of claim 1, wherein L2 can receive information relating to LI averaging techniques via a Param. response message in an initial phase.

3. The RAN of claim 1, wherein L2 can configure: one of the interference averaging techniques to LI; or parameters for one of the interference averaging techniques to LI; or one of the interference averaging techniques and parameters associated with theinterference technique separately for Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH).

4. The RAN of claim 1, wherein the system can use per De-Modulation Reference Signal (DMRS) symbol wise interference reporting to optimize scheduling in L2.

5. The RAN of claim 4, wherein L2 can request a DMRS symbol -wise interference report through a bitmap-based parameter configured in an Uplink Transmission Time Interval (UL.TTI) request message.

6. The RAN of claim 4, wherein LI can report back the per DMRS symbol interference on a per symbols basis from LI through parameters in a Cyclic Redundancy Check (CRC) indication message.

7. The RAN of claim 4, wherein L2 can request per DMRS symbol wise interference reporting separately for Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH).

8. A method for measuring interference in cloud-based Radio Access Network (RAN) utilizing Small Cell Forum 5G-Functional Application Platform Interface (SCF-FAPI) having a Centralized Unit (CU) coupled to a Distributed Unit (DU) and a plurality of Radio Units (RUs) each having one or more sectors, the plurality of RUs coupled to the DU where each RU is adapted to have a plurality of User Equipment (UE) coupled to each RU, the method comprisingthe steps of: performing Layer 1 (LI) and Layer 2 (L2) processing in the DU, or hosting a LI module in a respective RU and hosting a L2 module in the DU; measuring remote gNodeB (gNB) interference; and reporting the measured interference using SCF-FAPI from LI to L2 to improve system performance, where LI is used to report a measurement methodology of LI to upper layers.

9. The method of claim 8, further comprising the step of:L2 receives information relating to LI averaging techniques via a Param. response message in an initial phase.

10. The method of claim 8, further comprising the step of:L2 configures one of the interference averaging techniques to LI; orL2 configures parameters for one of the interference averaging techniques to LI; orL2 configures one of the interference averaging techniques and parameters associated with the interference technique separately for Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH).

11. The method of claim 8, further comprising the step of using per De-Modulation Reference Signal (DMRS) symbol wise interference reporting to optimize scheduling in L2.

12. The method of claim 11, further comprising the step of L2 requests a DMRS symbolwise interference report through a bitmap-based parameter configured in an Uplink TransmissionTime Interval (UL.TTI) request message.

13. The method of claim 11, further comprising the step of LI reports back the per DMRS symbol interference on a per symbols basis from LI through parameters in a Cyclic Redundancy Check (CRC) indication message.

14. The method of claim 11, further comprising the step of L2 requests per DMRS symbol wise interference reporting separately for Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH).

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