5g NR pucch interference mitigation

Abstract

The present disclosure relates to interference mitigation in a gNB for 3GPP NR using Long PUCCH formats 1 and 3 where both PUCCH Common and HARQ ACK are multiplexed in the same Long PUCCH Fl resources and the gNB assigns UE in a manner to achieve uniform resource allocation across the same Long PUCCH Fl resources in each slot or across resources in each slot and across all slots in the SR periodicity. Additionally, the gNB may assign UE in a manner to achieve uniform resource allocation across the same Long PUCCH F3 resources in each slot and across all slots in the CSI periodicity, or the gNB may assign UE in a manner to achieve uniform resource allocation across the resources in each slot including Long PUCCH F3 used by HARQ ACK, and the combination of HARQ ACK and CSI and SR.

Description

5G NR PUCCH INTERFERENCE MITIGATIONBACKGROUND1. Field of the Disclosure

[0001] The present disclosure is related to Third Generation Partnership Project (3GPP) Fifth Generation New Radio (5G NR) cellular wireless communication systems that is related to Physical Uplink Control Channel (PUCCH) long formats. More particularly, the present disclosure is related to interference mitigation for 3GPP NR for long PUCCH formats.2. Description of Related Art

[0002] Third Generation Partnership Project (3GPP) Fifth Generation New Radio (5GNR) Physical Uplink Control Channel (PUCCH) is used to transfer Uplink Control Information (UCI) from the User Equipment (UE) to the next generation Node B (gNB). This includes Hybrid Automatic Repeat reQuest Acknowledgements (HARQ ACK), Scheduling Requests (SR) and periodic and semi-persistent Channel State information (CSI) reports. 3GPP TS 38.211 specifics five PUCCH formats. Formats 1 and 3 are the “long PUCCH formats” or simply the “long PUCCH” as the durations are 4 to 14 symbols.

[0003] Format 1 has low capacity occupying only a single Resource Block (RB) in the frequency domain. Format 1 allows for code multiplexing of UE within shared time / frequency resources, that is, multiple UE can transmit using the same time / frequency resources to the gNB where each signal can be separated by codes. This code multiplexing increases Format 1 capacity. Format 1 allows up to 12 cyclic shifts (CS) and up to 7 Orthogonal Cover Codes (OCC). That is the multiplexing capacity can be as many as 12 x 7 = 84. However, in practice, a smaller number ofCS and OCC are used to lower the interference between them due to RF channel condition.

[0004] The payload size of Format 1 (Fl) is 1 or 2 bits, so it is used for PUCCH Common, which includes HARQ ACK for Physical Random Access Channel (PRACH) message 4, HARQ ACK for Physical Downlink Shared Channel (PDSCH) with up to 2 component-carrier (CC) carrier aggregation (CA) and SR.

[0005] Format 3 (F3) has a high capacity occupying up to 16 RB. In practice, the number of RB depends on the payload size and desired code rate. In general, higher payload size requires a higher number of RB to maintain the desired code rate. There is no code multiplexing so only one UE can be assigned to this resource. The payload size is more than 2 bits, so it is used for HARQ ACK with more than 1 CC CA and CSI reports.

[0006] A NR operator needs to dimension the long PUCCH to determine the number of RB for each long PUCCH format for the number of UE’s to be supported by the system. One example according to the prior art is shown in FIG. 1 as option 1 .

[0007] Because Format 3 duration can be 4-14 symbols long, 7 symbols can be chosen for the Format 3 resources. This requires a smaller number of RBs with the same CSI resources as seen in FIG. 2 as option 2.

[0008] FIGS. 1 and 2 show examples when one RB of PUCCH Fl is assigned for PUCCH Common and HARQ. Frequency hopping is where half of the RB (symbol 0 to 6 and 7 to 13) are located on different ends of the carrier in RB 0 and N-l, respectively, where N is the total number of RB of the operating carrier. This is done to exploit frequency diversity to improve reliability.

[0009] An example resource table for code multiplexing and the typical sequential resource assignment by the gNB is shown in FIG. 3 according to the prior art. This example provides a Format 1 resource table for PUCCH Common and HARQ in each slot. Resource Indices 0 - 3 are all using OCC 0 (and at the 2nd half-slot of RB 0) and they are using different CS 0, 3, 6 and 9, respectively. Similarly, Resource Indices 4 - 7 are all using OCC 1 (and at the 1st half-slot of RB N-l) and they are using different CS 0, 3, 6 and 9, respectively. Typical resource assignments are sequential, that is, they start from resource index 0, then 1 and so on. The order of UE is determined by UE priority at the scheduler. In this example, UE 1 is assigned with resource index 0, UE 2 is using resource index 1 and so on in slot 0. The same allocation method is applied in subsequent slots.

[0010] FIGS. 1 and 2 also show one RB of PUCCH Fl is assigned for SR. SR periodicity can encompass more than 1 slot, e.g., 10 slots or 10 ms for 15 MHz SCS (see TS38.331 for other choices). That is, there are 8 x 10 = 80 resources that gNB can assign different UEs in this example. When the UE attaches hand-ins (handover into the cell) or re-establishes (after UE has experienced Radio Link Failure), the gNB assigns one of 80 resources to the UE.

[0011] FIG. 4 shows typical SR resource allocations to UEs as is commonly known in the art. The gNB assigns SR to the UE sequentially.

[0012] FIGS. 1 and 2 also assign 4 RB (4 resources) for CSI report. CSI periodicity can be more than 1 slot, e.g., 80 slots or 80 mS for 15 MHz SCS (see TS38.331 for other choices). That is, there are 4 x 80 = 320 resources that gNB can assign different UEs in this example. When the UE arrives (attaches, hands-ins or re-establishes), the gNB assigns one of these resources to the UE for its PCell and for every SCell addition the gNB configures by sending RRCreconfiguration message to the UE afterwards. For example, if the UE has 4 CCs (1 PCell and 3 SCells) then the gNB assigns 4 CSI resources to the UE so it can report CSI from all 4 CCs.

[0013] FIG. 5 shows a typical example of CSI report resource allocation where the allocation is sequential per UE and per CC for both options 1 and 2 as illustrated in FIGS. 1 and 2.

[0014] Further, FIGS. 1 and 2 assign 2 RB (2 resources) of Format 3 for UE to report HARQ ACK when PCell and more than 2 SCells are used in the same slot. This resource can also be used for UE to send HARQ ACK + CSI + SR CSI report and / or SR are available in the same slot because this also requires more than 2 bits, which can be seen with reference to FIG. 6.However, the sequential allocation previously described can create interference problems among neighboring cells.

[0015] FIG. 7 is an example of a typical cellular network. UE 101 is served by Cell 1 for a 3- sector site. UE 201 is served by Cell 2. When UE 101 transmits long PUCCH Format 1 or 3, Signal 101,1 is detected by Cell 1 . This transmission can also be received by Cell 2 as Interference 101,2 and by Cell 3 as Interference 101,3, respectively. The received interference is stronger if UE 101 is at the edge of Cell 1 as it is closer to Cell 2 and Cell 3. Similarly, when UE 201 transmits long PUCCH Format 1 or 3, Signal 201,2 is detected by Cell 2. This also creates interference to Cell 1 as Interference 201,1 and interference to Cell 3 as Interference 201,3.

[0016] In typical sequential Long PUCCH allocations as per the examples shown in connection with FIGS. 3 - 5, the allocation from all cells starts from resource index 0 as previously discussed. This creates high interference in the lower resource indices while low or no interference in higher resource indices when there is a low number of UE in the cells. This interference could be mitigated if each cell avoids using the same resources.

[0017] FIG. 8 shows an example of sequential allocation of PUCCH Common / HARQ Format 1 for Cell 1, 2 and 3 in one of the slots. UE 101, 201 and 301 are using the same resource location, hence, they can interfere with each other once they transmit the PUCCH Common or HARQ.

[0018] A similar example can be shown for SR Format 1 in FIG. 9. FIG. 9 shows an example of the sequential allocation of SR Format 1 in Cell 1, 2 and 3, assuming for simplicity there are 20 UEs in each cell.

[0019] FIG. 10 shows an example of sequential allocation for CSI report resource PUCCH Format 3. The value 101-1 is the allocation of UE 101 for its carrier 1 (PCell). The gNB assigns each UE the CSI report resource of each carrier in a different slot so UE has enough transmission power even at cell edge. The allocations of all 3 cells are clustered in lower resources indices and slot numbers. This, however, unfortunately creates interference with each other.

[0020] Accordingly, there is a need for method that overcomes, alleviates, and / or mitigates one or more of the aforementioned and other deleterious effects of prior art relating to resource allocations that increase interference for 3 GPP NR for long PUCCH formats.SUMMARY

[0021] What is needed then is a system and a method that minimizes or mitigates interference for long PUCCH formats.

[0022] It is also desired to provide a system and a method that allocates resources in such a way as to limit interference for 3GPP NR for long PUCCH formats

[0023] It is further desired to provide a system and a method that mitigates interference for UCIfrom UE to gNB.

[0024] It is still further desired to provide a system and a method that mitigates interference in the transfer of HARQ ACK, SR and CSI reports sent from UE across multiple cells.

[0025] In one configuration a method is provided to mitigate interference due to long PUCCH Format 1 and Format 3 transmission among multiple cells. This is variously achieved by:1) Using Long PUCCH Format 1 used by PUCCH Common, HARQ ACK (up to 2 bits).2) Using Long PUCCH Format 1 used by SR.3) Using Long PUCCH Format 3 used by CSI report (more than 2 bits).4) Using Long PUCCH Format 3 used by HARQ ACK (more than 2 bits) and HARQ ACK+CSI+SR (total number of bits is more than 2 bits).

[0026] The method further includes using one of the following resource assignment methods: 1) uniform resource allocation; and 2) multi-level load balancing.

[0027] For this application the following terms and definitions shall apply:

[0028] 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.

[0029] 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.

[0030] The terms “first” and “second” are used to distinguish one element, set, data, object or thing from another, and are not used to designate relative position or arrangement in time.

[0031] 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, files, 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.

[0032] 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.

[0033] In one configuration a method for interference mitigation in a next generation Node B (gNB) for Third Generation Partnership Project New Radio (3 GPP NR) using Long PhysicalUplink Control Channel (PUCCH) formats 1 and 3 is provided comprising the steps of for a first configuration comprising Long PUCCH Format 1 (Fl) used by PUCCH Common, Hybrid Automatic Repeat reQuest Acknowledgements (HARQ ACK), where both PUCCH Common and HARQ ACK are multiplexed in the same Long PUCCH Fl resources, the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH Fl resources in each slot. The method further comprises the step of a second configuration comprising Long PUCCH Fl used by Scheduling Requests (SR), the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH Fl resources in each slot and across all slots in the SR periodicity. The method still further comprises the step of a third configuration comprising Long PUCCH Format 3 (F3) used by Channel State information (CSI) reports, the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH F3 resources in each slot and across all slots in the CSI periodicity. Finally, the method further comprises the step of a fourth configuration comprising Long PUCCH F3 used by HARQ ACK, and the combination of HARQ ACK and CSI and SR, the gNB assigns UE in a manner to achieve uniform resource allocation across the resources in each slot.

[0034] In another configuration, for the first, second, third and fourth configurations as described above, upon UE connection to a gNB among a plurality of gNBs, multi-level load balancing is used in connection with a gNB assigned a time resource slot (s) that has the least number of assignments, and a frequency resource (r) that has the least number of assignments so as to minimize interference across the plurality of gNBs.

[0035] In still another configuration, a system for interference mitigation in a next generation Node B (gNB) for Third Generation Partnership Project New Radio (3 GPP NR) usingLong Physical Uplink Control Channel (PUCCH) formats 1 and 3 is provided comprising: a gNB adapted to assign user equipment (UE) in a manner to achieve uniform resource allocation. The system is provided so that for a first configuration comprising Long PUCCH Format 1 (Fl) used by PUCCH Common, Hybrid Automatic Repeat reQuest Acknowledgements (HARQ ACK), where both PUCCH Common and HARQ ACK are multiplexed in the same Long PUCCH Fl resources, the gNB assigns user equipment (UE) across the same Long PUCCH Fl resources in each slot. The system is further provided so that for a second configuration comprising Long PUCCH Fl used by Scheduling Requests (SR), the gNB assigns user equipment (UE) across the same Long PUCCH Fl resources in each slot and across all slots in the SR periodicity. The system is still further provided so that for a third configuration comprising Long PUCCH Format 3 (F3) used by Channel State information (CSI) reports, the gNB assigns user equipment (UE) across the same Long PUCCH F3 resources in each slot and across all slots in the CSI periodicity. Finally, the system is provided so that for a fourth configuration comprising Long PUCCH F3 used by HARQ ACK, and the combination of HARQ ACK and CSI and SR, the gNB assigns UE across the resources in each slot.

[0036] 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

[0037] FIG. 1 illustrates a first example of Resource Block (RB) assignment of PUCCH format 1 and format 3 to PUCCH Common, HARQ, SR and CSI (14 symbol duration), separately and combination of these according to the prior art.

[0038] FIG. 2 illustrates a second example of RB assignment of PUCCH format 1 and format 3 to PUCCH Common, HARQ, SR and CSI (7 symbol duration), separately and combination of these according to the prior art.

[0039] FIG. 3 illustrates a Format 1 resource table for PUCCH Common and HARQ according to the prior art.

[0040] FIG. 4 illustrates a typical SR resource allocation to UE according to the prior art.

[0041] FIG. 5 illustrates CSI report resource allocation for both the first and second examples according to FIGS. 1 and 2.

[0042] FIG. 6 illustrates HARQ ACK Format 3 and typical sequential allocation according to the prior art.

[0043] FIG. 7 illustrates a typical cellular network with UE creating interference to other cells according to the prior art.

[0044] FIG. 8 illustrates the sequential allocation of PUCCH Common / HARQ Format 1 according to the prior art.

[0045] FIG. 9 illustrates sequential allocation of SR Format 1 in Cell 1, 2 and 3 according to the prior art.

[0046] FIG. 10 illustrates sequential allocation for CSI report resource PUCCH Format 3 according to the prior art.

[0047] FIG. 11 illustrates uniform resource allocation for Format 1 PUCCH Common and HARQ ACK according to one configuration of the disclosure.

[0048] FIG. 12 illustrates uniform resource allocation of SR Format 1 according to the configuration of FIG. 11.

[0049] FIG. 13 illustrates uniform resource assignment for CSI report resource Format 3 (with 10 slots) according to the configuration of FIG. 11.

[0050] FIG. 14 illustrates uniform resource assignment for HARQ ACK Format 3 according to the configuration of FIG. 11.

[0051] FIG. 15 illustrates Multi-Level Load Balancing for PUCCH Common and HARQ ACK Format 1 according to the configuration of FIG. 14.

[0052] FIG. 16 illustrates half-slot and CS steps in the Multi-Level Load Balancing according to the configuration of FIG. 15.

[0053] FIG. 17 illustrates a graphical explanation of the Muti -Level Load Balancing according to the configuration of FIG. 15.

[0054] FIG. 18 illustrates Multi-Level Load Balancing for SR Format 1 with 10, 15 and 25 UE’s in cell 1, 2 and 3, respectively according to the configuration of FIG. 15.

[0055] FIG. 19 illustrates Multi-Level Load Balancing for CSI Report Resource for 4 CC for each UE, 5 UE per cell according to the configuration of FIG. 15.

[0056] FIG. 20 illustrates Multi-Level Load Balancing for CSI Report Resource for 4 CC for the first UE with DRX constraint according to the configuration of FIG. 15.DETAILED DESCRIPTION

[0057] Referring to the drawings and in particular to FIG. 11, the method for uniform resource allocation is depicted. Upon UE arrival (attaches, hand-ins or reestablishes) to the cell, the gNB assigns resources in a manner to achieve uniform resource allocation. For PUCCH Common and HARQ ACK Format 1, where both are multiplexed in the same Long PUCCH Format 1 resources, the allocation spreads the UE in a manner to achieve uniform resource allocation.

[0058] FIG. 11 shows an example of uniform resource allocation for Format 1 PUCCH Common and HARQ ACK. In slot 0, UE 101 needs PUCCH Common, the gNB assigns UE 101 in resource index 2 to transmit PRACH message 4. UE 102 and UE 103 are allocated uniformly to resource indices 0 and 5, respectively. This would change in every slot as PUCCH Common and HARQ ACK are allocated on a per slot basis. The allocation is also uniform in other cells, therefore, if all resources in a slot are not repeated, the chance of having the same allocation in the same resource index can be minimized, hence, mitigating the inter-cell interference.

[0059] The same method can be applied to SR Format 1. Unlike the allocation of PUCCH Common and HARQ ACK where it is performed slot by slot, the SR Format 1 can be assigned uniformly for the entire SR periodicity. In the example where there are 8 SR resources per slot and 10 slot periodicities, there are 80 resources per SR periodicity.

[0060] FIG. 12 shows an example of uniform resource allocation of SR Format 1. The allocation of all UE’s is uniformly spread out. Statistically, UE’s in a cell would be less likely to use the same resource as UE’s in other cells, thereby minimizing potential interference. However, it is still possible to see instances where they are using the same resources, such as resource index 1 in slot 6 where UE 118, 204 and 310 are assigned, so is resource index 2 in slot 6.

[0061] FIG. 13 shows an example for CSI report resource with PUCCH Format 3 in which thesame method can be used. The help with visualization, it is assumed 5 UE and only 10 slots in the example. It should be noted that CSI reporting from a UE should be within the DRX onDuration+4ms period for all the CCs. As such, it is better to have a starting slot and PRB for pCell that is shifted and then other CCs are allocated in consecutive slots (PRB resource can be shifted).

[0062] In another configuration, the CSI reports from a UE can be within its DRX On Duration because the UE may decide not to transmit the CSI report if the UE is not within the On Duration. The DRX On Duration can be as small as 1 mS, by typical value would be between 4- 10 mS. To support this additional constraint, the gNB assigns the UE the slot number and the resource index for the PCell uniformly, then assigns the slot number as the DRX start slot. Finally, the gNB assigns the rest of CSI reports to the slot numbers between the DRX start slot to DRX start slot + DRX On Duration. For example, the gNB assigns UE 101 the CSI report resource for the PCell to be slot 0 (101-1 is assigned in slot 0), and the DRX On Duration is 4 mS, then the SCells 1, 2 and 3 (101-2, 101-3, 101-4) could be in slots 1, 2 and 3, respectively. Their resource indexes can be assigned uniformly.

[0063] FIG. 14 shows an example where the uniform resource allocation method is simple and statistically mitigates the inter-cell interference. For Long PUCCH Format 3 used by HARQ ACK, the gNB assigns UE uniformly across the resources in each slot. However, in some instances, it could still allow the same resource usage among cells. In this case, multi-Level Load Balancing is another method to further mitigate potential interference. It applies slightly differently per assignment purpose, but the key idea is to ensure the same number of UE in each of time resources (slot) and frequency resources (full-slot, half-slot and Cyclic Shift separation) so that potential interference is not unduly raised among multiple cells.

[0064] For PUCCH Common and HARQ ACK Format 1, the gNB 1) selects the half-slot (OCC) that has the least number of UE assignments (break tie randomly); and 2) once the half slot is chosen, select CS that is 2 indices apart, if possible, out of CS 0, 3, 6, 9 (break tie randomly).

[0065] The half-slots are orthogonalized by the OCC and in the example, dimension OCC 0 and OCC 1, for a total of two half-slots. The CS is cyclical, for example, the difference between 0 and 9 is one index apart. This will reduce interference among UE of the same cell within the same half-slot.

[0066] FIG. 15 shows an example of Half-Slot Load Balancing for PUCCH Common and HARQ ACK Format 1 . Resource allocations are spread out across multiple cells and spread out between half-slots. This reduces both intra-cell and inter-cell interference.

[0067] FIG. 16 explains half-slot and CS steps in the Multi-Level Load Balancing done in FIG. 15 for UE’s 101-108 in Cell 1. Without loss of generality, the gNB ranks the UE priority to schedule by its ID from 101 to 108. The gNB first picks a half-slot (HS) out of two (break tie randomly) it selects HS 0. Next, the gNB may select a CS to achieve uniform resource allocation but can be chosen randomly in this instance as there is no other UE. In this example, it selects CS 6. Because the number of UE in HS 0 is 1 and in HS 1 is 0, then the gNB assigns UE 102 to HS 1. The gNB selects CS in a manner to achieve uniform resource allocation, e g., CS 3. UE 103 will be assigned to HS as the number of UE in each HS is equal. Select HS 0 for UE 103. Because UE 101 is in CS 6, the gNB selects the most distance from CS 6, which is CS 0 to the UE 103. UE 104 is assigned to HS 1 to balance the load between HS and to CS 9 to be at the most distance from CS 3 occupied by UE 102. HS is selected in a manner to achieve uniform resource allocation for UE 105 and in HS 1. HS can be selected in a manner to achieve uniformresource allocation on either CS 0 or CS 6 as 2-index distance is not possible anymore. The process continues until the gNB runs out of UE to serve or all resource indices are occupied.

[0068] For SR Format 1, a Multi-Level Load Balancing method is provided. For new UE arrival the method includes:1) List the half-slot(s) that have smallest number of UE assignment as hsCntMinldx.2) List the slot(s) that have the smallest number of UE assignment as slotCntMinldx.3) Create a list of half-slot & slot resources (hs, s) where hs is from hsCntMinldx and s is from slotCntMinldx, denoted IbCandidates.4) Remove any resource(s) from the list IbCandidates that have already been assigned.5) Select the half-slots & slot resource (hs*, s*) in a manner to achieve uniform resource allocation from the final IbCandidates list.6) If the IbCandidates list is empty from the above first pass, then select the first available resource as follows: a) Go through the half-slot hs in hsCntMinldx sequentially and select the first slot that has not been occupied; b) If the above fails, go through the slot s in slotCntMinldx list sequentially and select the first half-slot that has not been occupied.7) Assign the UE with the resource (hs*, s*).8) Assign CS resources as described previously for PUCCH Common / HARQ FL

[0069] FIG. 17 shows an illustration of the Muti -Level Load Balancing for SR Format 1 (before CS assignment). In one example, slots 3 and 5 have the lowest number of assigned UE’s, then slotCntMinldx list contains {3, 5} . Supposed also that half-slot 2 has the lowest number of assigned UEs, then the gNB selects half-slot hs* = 2. Then select slot s* from slots 3 or 5 whichever the number of assigned UE in (2, 3), resource A or (2, 5), resource B, is smaller.

[0070] FIG. 18 shows an example of Multi-Level Load Balancing (LB) for SR Format 1 with 10, 15 and 25 UEs in cell 1, 2 and 3, respectively. With slot LB, gNB assigns 1 UE in each slotequally in cell 1 and 5 equally in each half-slot. In cell 2, 5 slots have 1 UE, and the other 5 slots have 2 UEs. The distribution is in done to achieve uniform resource allocation. The half-slot 1 and 2 have 8 and 7 UEs, respectively. In cell 3, 5 slots have 2 UEs while the other 5 slots has 3 UEs. In the slot where more than one UE, the other UE takes CS 6, which is 2 CS away from CS 0. This allocation spreads the resource usage evenly over time (slot), frequency (half-slot) and code (cyclic shift). As such, this configuration minimizes the intra-cell and inter-cell interference.

[0071] For CSI Report Format 1, the Multi-Level Load Balancing method involves the following steps. For CSI Report for UE u, CC c, the gNB shall:1) List the slot(s) that have the smallest number of UE assignment as slotCntMinldx.2) Select the frequency resource, f, that is, Option 1, full-slot, one resource = 1 RB x 14 symbols (full-slot) or Option 2, one resource = 1 RB x 7 symbols (half-slot), that have the smallest number of UE assignments, denoted resCntMinldx.3) Create a list of frequency resource & slot resources (r, s) where r is from resCntMinldx and s is from slotCntMinldx, denoted IbCandidates.4) Remove any resource(s) from the list IbCandidates that have already been assigned.5) Select the frequency resource & slot resource (r*, s*) in a manner to achieve uniform resource allocation from the final IbCandidates list.6) If the IbCandidates list is empty from the above first pass, then select the first available resource as follows: a) Go through the frequency resource r in resCntMinldx sequentially and selects the first slot that has not been occupied; b) If the above fails, go through the slot s in slotCntMinldx list sequentially and selects the first frequency resource that has not been occupied.7) Assign the UE with the resource (r*, s*).

[0072] FIG. 19 illustrates Multi-Level Load Balancing for CSI Report Resource for 4 CC for each UE, with 5 UE per cell. This again shows reduced total CSI Report resources to better illustrate the concept. For each UE and CC assigned, the gNB maintains the number ofassignments in both slot and frequency resource dimensions.

[0073] In another embodiment, the CSI reports from a UE can be within its DRX On Duration because the UE may decide not to transmit the CSI report if the UE is not within the On Duration. To support this additional constraint, the gNB shall:1) Assign the UE the slot resource and the frequency resource for the PCell based on the procedure above.2) Assign the PCell slot resource as the DRX start slot.3) Assign the next slot resource for the SCell between the DRX start slot and DRX start slot + DRX On Duration, in the slot resource with the least number of assignments. Break tie randomly.4) Assign the frequency resource with the least number of assignments. Break tie randomly.5) Repeat for the rest of the SCells.

[0074] This assumes that the operator has set the DRX On Duration to be equal or more than the number of slot resources required for all CC of the UE.

[0075] FIG. 20 shows an example of Multi-Level Load Balancing for CSI Report Resource for 4 CC for a UE with DRX constraint on the first UE assignment. The gNB assigns UE 101 the CSI report resource for the PCell in slot 6 (101-1 is assigned in slot 6) with frequence resource 1, and supposed the DRX On Duration is 4 mS, then the SCells 1, 2 and 3 (101-2, 101-3, 101-4) could be in slots 7, 8, and 9, respectively. The gNB selects 101-2 in slot 7 and frequency resource 3 to maintain load balancing in frequency. It continues assignments for 101-3 and 101-4 in the same way. Note that the slot assignment will be wrapped around because the slot indices repeat continuously. That is if the first slot for 101-1 is slot 7, then 101-2, 101-3 and 101-4 are in slots 8, 9 and 0, respectively.

[0076] When the UE departs from the cell, the gNB frees up its resources, then assigns them to the new arrival UEs. This is applicable for UE with different numbers of CC. A UE can configure a new SCell CC later, and the gNB processes the new CSI Report resource request the same way.

[0077] For HARQ ACK Format 3, the gNB selects the resource on a per-slot basis when one or multiple UEs need to transmit HARQ ACK for the DL transmission in previous kl slots (for example, kl = 4 slots). The number of UEs varies based on traffic demand. The gNB keeps count of the number of resource assignments over multiple slots, then in the next slot, it selects the resource that has been assigned the least. This ensures that, on each slot, all resources are likely to be used equally, hence, minimizing any potential interference to other cells. In the long-term statistics, the resource distribution is uniform and is the same as the uniform resource allocation described earlier. However, in the short term, load balancing would offer a more uniform distribution as only one dimension resource must be considered where multi-level load balancing degenerates to one-dimensional (simple) load balancing.

[0078] The Multi-Level Load Balancing method involves the following steps. For HARQ ACK for UE u, in slot s, the gNB shall:1) Select the resource, r, that have the smallest number of UE assignments. Break tie randomly.2) Assign the UE with the selected resource.3) Repeat for the remaining UE in slots.4) Update the assignment count for all resources.

[0079] The innovation can be extended to all possible BWs defined for 5G NR systems / any BW Part. It can also be extended to a greater number of SR / CSI / HARQ resources (more number ofusers) of different reporting formats such as various reporting items given in 3GPP: RSRP, CRT. Additionally, this can be extended to Long PUCCH format 4. Load balancing can be across one or more DUs / CUs or any machines where RRM for a cell is running.

[0080] This configuration can cover the case when the number of RBs for each PUCCH format is unequal among cells, if the operator chooses to do so. The uniform resource allocation or multi-level load balancing spreads out the assignments for all PUCCH formats therefore it mitigates the interference the same way.

[0081] 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 situation or 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 method for interference mitigation in a next generation Node B (gNB) for Third Generation Partnership Project New Radio (3 GPP NR) using Long Physical Uplink Control Channel (PUCCH) formats 1 and 3 comprising the steps of: for a first configuration comprising Long PUCCH Format 1 (Fl) used by PUCCH Common, Hybrid Automatic Repeat reQuest Acknowledgements (HARQ ACK), where both PUCCH Common and HARQ ACK are multiplexed in the same Long PUCCH Fl resources, the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH Fl resources in each slot; for a second configuration comprising Long PUCCH Fl used by Scheduling Requests (SR), the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH Fl resources in each slot and across all slots in the SR periodicity; for a third configuration comprising Long PUCCH Format 3 (F3) used by Channel State information (CSI) reports, the gNB assigns user equipment (UE) in a manner to achieve uniform resource allocation across the same Long PUCCH F3 resources in each slot and across all slots in the CSI periodicity; and for a fourth configuration comprising Long PUCCH F3 used by HARQ ACK, and the combination of HARQ ACK and CSI and SR, the gNB assigns UE in a manner to achieve uniform resource allocation across the resources in each slot.

2. The method according to claim 1, wherein for the first, second, third and fourthconfigurations, upon UE connection to a gNB among a plurality of gNBs, multi-level load balancing is used in connection with a gNB assigned a time resource slot (s) that has the least number of assignments, and a frequency resource (r) that has the least number of assignments so as to minimize interference across the plurality of gNBs.

3. The method according to claim 2, wherein the UE connection includes: attaching, hand-ins or reestablishment; and the frequency resource includes: full-slot (fs), half-slot (hs) and Cyclic Shift (CS) separation.

4. The method according to claim 3, wherein for the first configuration the method further comprising the steps of: the gNB selects a hs Orthogonal Cover Code (OCC) that has the least number of UE assignments; and after the hs is chosen, the gNB selects a CS that is 2 indices apart, out of CS 0, 3, 6, 9.

5. The method according to claim 4, wherein for the second configuration multi-level load balancing is provided for new UE connection, and the method further comprising the steps of:1) the gNB lists a hs that has a smallest number of UE assignments as hsCntMinldx;2) the gNB lists a fs that has a smallest number of UE assignments as slotCntMinTdx;3) the gNB creates a list of hs and fs resources where the hs is from hsCntMinldx and the fs is from slotCntMinldx, denoted IbCandidates;4) the gNB removes any resource from the list IbCandidates that have already beenassigned;5) the gNB selects a hs and a fs resource (hs*, fs*) in a manner to achieve uniform resource allocation from a final IbCandidates list;6) wherein if the IbCandidates list is empty from a step 5), then a first available resource is selected as follows: a) search for hs in hsCntMinldx sequentially and select a first fs that has not been occupied; and b) if 1) fails, search for fs in slotCntMinldx list sequentially and select a first hs that has not been occupied;7) the gNB assigns the UE with the resource (hs*, fs*); and8) the gNB assigns CS resources as described for the first configuration.

6. The method according to claim 5, wherein for the third configuration multi-level load balancing is provided for CSI Report for UE component-carrier (CC), and the method further comprising the steps of1) the gNB lists a slot that has a smallest number of UE assignments as slotCntMinldx;2) the gNB selects a r, that is, a) a fs where one resource = 1 RB x 14 symbols, or b) a hs where one resource = 1 RB x 7 symbols, that have the smallest number of UE assignments, denoted resCntMinldx;3) the gNB creates a list of r and s where r is from resCntMinldx and s is from slotCntMinldx, denoted IbCandidates;4) the gNB removes any resource from the list IbCandidates that has already beenassigned;5) the gNB selects an r and an s (r*, s*) in a manner to achieve uniform resource allocation from a final IbCandidates list;6) wherein if the IbCandidates list is empty from a step 5), then a first available resource is selected as follows: : a) search for r in resCntMinldx sequentially and select a first s that is unoccupied; and b) if there is no unoccupied s, search for s in slotCntMinldx list sequentially and select the first r that has not been occupied;7) the gNB assigns the UE with the resource (r*, s*).

7. The method according to claim 6, wherein for the fourth configuration multi-level load balancing is provided for HARQ ACK for UE in a slot, and the method further comprises the steps of:1) the gNB selects r that has the smallest number of UE assignments;2) the gNB assigns the UE with the selected resource;3) the gNB repeats for a remaining UE in the slot; and4) the gNB updates the assignment count for all resources.

8. The method according to claim 7, wherein in the event of a tie in the step of the gNB selects r that has the smallest number of UE assignments, the tie is broken by random selection.

9. A system for interference mitigation in a next generation Node B (gNB) for ThirdGeneration Partnership Project New Radio (3GPP NR) using Long Physical Uplink Control Channel (PUCCH) formats 1 and 3 comprising: a gNB adapted to assign user equipment (UE) in a manner to achieve uniform resource allocation; wherein for a first configuration comprising Long PUCCH Format 1 (Fl) used by PUCCH Common, Hybrid Automatic Repeat reQuest Acknowledgements (HARQ ACK), where both PUCCH Common and HARQ ACK are multiplexed in the same Long PUCCH Fl resources, the gNB assigns user equipment (UE) across the same Long PUCCH Fl resources in each slot; wherein for a second configuration comprising Long PUCCH Fl used by Scheduling Requests (SR), the gNB assigns user equipment (UE) across the same Long PUCCH Fl resources in each slot and across all slots in the SR periodicity; wherein for a third configuration comprising Long PUCCH Format 3 (F3) used by Channel State information (CSI) reports, the gNB assigns user equipment (UE) across the same Long PUCCH F3 resources in each slot and across all slots in the CSI periodicity; and wherein for a fourth configuration comprising Long PUCCH F3 used by HARQ ACK, and the combination of HARQ ACK and CSI and SR, the gNB assigns UE across the resources in each slot.

10. The system according to claim 9, wherein for the first, second, third and fourth configurations, upon UE connection to a gNB among a plurality of gNBs, multi-level load balancing is used in connection with a gNB assigned a time resource slot (s) that has the least number of assignments, and a frequency resource (r) that has the least number of assignments soas to minimize interference across the plurality of gNBs.

11. The system according to claim 10, wherein the UE connection includes: attaching, hand-ins or reestablishment; and the frequency resource includes: full-slot (fs), half-slot (hs) and Cyclic Shift (CS) separation.

12. The system according to claim 11, wherein for the first configuration the gNB is adapted to select a hs Orthogonal Cover Code (OCC) that has the least number of UE assignments and after the hs is chosen, the gNB is adapted to select a CS that is 2 indices apart, out of CS 0, 3, 6, 9.

13. The system according to claim 12, wherein for the second configuration multi-level load balancing is provided and for new UE connection:1) the gNB is adapted to list a hs that has a smallest number of UE assignments as hsCntMinldx;2) the gNB is adapted to list a fs that has a smallest number of UE assignments as slotCntMinldx;3) the gNB is adapted to create a list of hs and fs resources where the hs is from hsCntMinldx and the fs is from slotCntMinldx, denoted IbCandidates;4) the gNB is adapted to remove any resource from the list IbCandidates that have already been assigned;5) the gNB is adapted to select a hs and a fs resource (hs*, fs*) in a manner to achieveuniform resource allocation from a final IbCandidates list;6) wherein if the IbCandidates list is empty from a step 5), then the gNB is adapted to select a first available resource as follows: a) search for hs in hsCntMinldx sequentially and select a first fs that has not been occupied; and b) if 1) fails, search for fs in slotCntMinldx list sequentially and select a first hs that has not been occupied;7) the gNB is adapted to assign the UE with the resource (hs*, fs*); and8) the gNB is adapted to assign CS resources as described for the first configuration.

14. The system according to claim 13, wherein for the third configuration multi-level load balancing is provided for CSI Report for UE component-carrier (CC):1) the gNB is adapted to list a slot that has a smallest number of UE assignments as slotCntMinldx;2) the gNB is adapted to select a r, that is, a) a fs where one resource = 1 RB x 14 symbols, or b) a hs where one resource = 1 RB x 7 symbols, that have the smallest number of UE assignments, denoted resCntMinldx;3) the gNB is adapted to create a list of r and s where r is from resCntMinldx and s is from slotCntMinldx, denoted IbCandidates;4) the gNB is adapted to remove any resource from the list IbCandidates that has already been assigned;5) the gNB is adapted to select an r and an s (r*, s*) in a manner to achieve uniformresource allocation from a final IbCandidates list;6) wherein if the IbCandidates list is empty from a step 5), then the gNB is adapted to select a first available resource as follows: a) search for r in resCntMinldx sequentially and select a first s that is unoccupied; and b) if there is no unoccupied s, search for s in slotCntMinldx list sequentially and select the first r that has not been occupied;7) the gNB is adapted to assign the UE with the resource (r*, s*).

15. The system according to claim 14, wherein for the fourth configuration multi-level load balancing is provided for HARQ ACK for UE in a slot:1) the gNB is adapted to select r that has the smallest number of UE assignments;2) the gNB is adapted to assign the UE with the selected resource;3) the gNB is adapted to repeat for a remaining UE in the slot; and4) the gNB is adapted to update the assignment count for all resources.

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