An apparatus and a method for resource allocation in a wireless communication network

Abstract

The embodiments disclose a method comprising: selecting a group of user equipment (UEs), among a plurality of UEs; obtaining for each UE in the selected group, a scheduling metric; determining a set of resource blocks (PRBs) for the selected group, based on the scheduling metric; and allocating, in SU-MIMO mode, PRBs from the determined set to at least one UE in the selected group, such that the number of allocated PRBs to each UE is restricted to a number at which the uplink transmit power of the UE does not exceed its maximum uplink transmit power limit; and in MU-MIMO mode in a second round, remaining PRBs from the determined set, to at least two UEs if each of the at least two UEs is allocated with PRBs that is lesser than the PRBs at which the UE achieves its maximum uplink transmit power limit.

Description

[0001] AN APPARATUS AND A METHOD FOR RESOURCE ALLOCATION IN A

[0002] WIRELESS COMMUNICATION NETWORK

[0003] Technical Field:

[0004] Various example embodiments of the present disclosure relate to the field of telecommunication, and more particularly relate to an apparatus and a method for resource allocation in a wireless communication network.

[0005] Background:

[0006] Certain abbreviations that may be found in the description and / or in the figures are herewith defined as follows.

[0007] 5G NR 5thGeneration New Radio

[0008] CN Core Network eNB Evolved Node B

[0009] FD Frequency Division gNB Next Generation Node B

[0010] LTE Long Term Evolution

[0011] LTE-A Long Term Evolution Advanced

[0012] MCS Modulation and Coding Scheme

[0013] MU-MIMO Multi-U ser Multiple-Input-Multiple-Output

[0014] OFDM Orthogonal Frequency Division Multiplexing

[0015] PF Proportional Fair

[0016] PRB Physical Resource Block

[0017] QoS Quality of Service

[0018] SC-FDMA Single Carrier Frequency-Division Multiple Access

[0019] SD Spatial Division

[0020] SDM Spatial Division Multiplexing

[0021] SE Spectral Efficiency SU-MIMO Single-User Multiple-Input-Multiple-Output

[0022] TBS Transport Block Size

[0023] UE User Equipment

[0024] UEG User Equipment Group

[0025] In a wireless communication network, a UE transmits signals / data towards the base station with the help of physical resource blocks (PRBs) that are allocated to it by a base station. PRBs include time and frequency resources. There is a maximum limit to the uplink transmit power of the UE for performing uplink transmissions with the help of the allocated PRBs. There may be certain situations where the UE may be allocated with an excess number of PRBs, which can result in sub- optimal PRB utilization by the UE. An example of such a situation is the following. When a UE is located at the edge of a cell, the UE is likely to have reached its maximum uplink transmit power limit (such a UE may also be referred to as power- limited UE). At this point, allocating further PRBs to the power-limited UE would reduce the power per PRB or power spectral density (the measure of a signal’s power vs frequency). This in turn may reduce the modulation and coding scheme (MCS), and thus affect the overall spectral efficiency (SE). In other words, because each UE has its own maximum uplink transmit power limit, an allocation of resources to a UE without considering its uplink transmit power limitation can hurt system performance. Additionally, excessive PRB allocation to a power-limited UE, can mean that non-power-limited UEs (UEs that have not reached their maximum uplink transmit power limit) may be deprived of those same PRBs, which could have resulted in assignment of higher MCS and SE.

[0026] Summary:

[0027] According to some aspects, there is provided the subject matter of independent claims. Some embodiments are defined in the dependent claims.

[0028] In a first aspect of the present disclosure, there is provided a method for resource allocation for a plurality of user equipment devices (UEs) in a wireless communication network. The method comprises: selecting a group of UEs (N) within the plurality of UEs; obtaining, for each UE in the selected group, a scheduling metric; determining a set of resource blocks (PRBs) for the selected group of UEs based on the obtained scheduling metric; and allocating, in SU-MIMO mode in a first round, resource blocks from the determined set of resource blocks to at least one UE in the selected group, such that the number of allocated resource blocks to each UE in the selected group is restricted to a number at which the uplink transmit power of the UE is lesser than or equal to its maximum uplink transmit power limit such that PSD limit is not reduced; and allocating in MU- MIMO mode in a second round, remaining resource blocks from the determined set of resource blocks, to at least two UEs (NSDM), within the selected group, on a determination that each of the at least two UEs is allocated with resource blocks that is lesser than the number at which the UE achieves its maximum uplink transmit power limit such that the PSD limit is not reduced.

[0029] In a second aspect of the present disclosure, there is provided an apparatus comprising at least one memory; at least one processor operatively coupled to the at least one memory, wherein the at least one processor is configured to cause the apparatus to: select a group of user equipment devices (UEs) within a plurality of UEs; obtain, for each UE in the selected group (N), a scheduling metric; determine a set of resource blocks (PRBs) for the selected group of UEs based on the obtained scheduling metric; and allocate, in SU-MIMO mode in a first round, resource blocks from the determined set of resource blocks to at least one UE in the selected group, such that the number of allocated resource blocks to each UE in the selected group is restricted to a number at which the uplink transmit power of the UE is lesser than or equal to its maximum uplink transmit power limit such that PSD limit is not reduced; and allocate in MU-MIMO mode in a second round, remaining resource blocks from the determined set of resource blocks, to at least two UEs (NSDM), within the selected group, on a determination that each of the at least two UEs is allocated with resource blocks that is lesser than the number at which the UE achieves its maximum uplink transmit power limit such that the PSD limit is not reduced.

[0030] In a third aspect of the present disclosure, there is provided a computer program product comprising instructions stored on a computer readable storage medium, wherein at least one processor of an apparatus is configured to execute the instructions to cause the apparatus to perform a process including the method of the first aspect. Brief Description of Drawings:

[0031] In the following, various exemplary embodiments will be described in greater detail with reference to the accompanying drawings, in which:

[0032] FIG. 1 illustrates a wireless communication system, according to an example embodiment of the disclosure herein;

[0033] FIG. 2 illustrates a sequence of physical resource block allocation, according to an example embodiment of the disclosure herein;

[0034] FIGS. 3 A to 3C illustrate a flowchart of three rounds of physical resource block allocation, according to an example embodiment of the disclosure herein;

[0035] FIG. 4 illustrates a process for Round 2 scheduling, according to an example embodiment of the disclosure herein;

[0036] FIG. 5 illustrates a flowchart for implementing spatial division multiplexing and physical resource block allocation, according to an example embodiment of the disclosure herein;

[0037] FIGS. 6A and 6B show a contrast between the physical resource block allocation methods, according to an example embodiment of the disclosure herein;

[0038] FIG. 7 illustrates a method for allocation of partially overlapping physical resource blocks, according to an example embodiment of the disclosure herein;

[0039] FIG. 8 illustrates a method for allocation of completely overlapping physical resource blocks, according to an example embodiment of the disclosure herein;

[0040] FIG. 9 illustrates a device that is suitable for implementing example embodiments of the disclosure herein; and FIG. 10 illustrates a method performed by a base station, according to an example embodiment of the disclosure herein.

[0041] Detailed Description

[0042] Example embodiments now will be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of the example embodiments illustrated in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements.

[0043] The specification may refer to “an”, “one” or “some” embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, whenever the phrase “at least one of the following” precedes a list of elements, wherein the elements are joined by “and” or “or”, it means that at least any one of the elements or at least all the elements are present. As used herein, the term “and / or” includes any and all combinations and arrangements of one or more of the associated listed items.

[0044] Conditional language — such as “can” or “may” — among others, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore, “connected” or “coupled” as used herein may include wirelessly connected or coupled.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0046] The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown. The connections shown are logical connections; the actual physical connections may be different. In addition, all logical units described and depicted in the figures include the software and / or hardware components required for the unit to function. Further, each unit may comprise within itself one or more components, which are implicitly understood. These components may be operatively coupled to each other and be configured to communicate with each other to perform the function of the said unit.

[0047] As used herein, the term “circuitry” may refer to at least one of the following: a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); or c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0048] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0049] Before explaining the example embodiments of the present disclosure in detail, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to FIG. 1 to assist in understanding the technology underlying the described examples.

[0050] FIG. 1 illustrates a wireless communication system 100 in an environment in which an example embodiment of the present disclosure can be implemented. The system 100 may comprise a base station 110 and three mobile communication devices or user equipment (UE) 120 A, 120B, and 120C (collectively “UEs 120A / B / C”). The base station 110 may provide wireless connections for the three UEs 120 A / B / C that can enable the three UEs 120A / B / C to wirelessly communicate with each other.

[0051] The base station 110 may be responsible for allocating (e.g., dynamic allocation) resources to the UEs 120A / B / C in both the uplink and downlink. By way of example rather than limitation, the base station 110 may be an evolved Node B (eNB in Long Term Evolution (LTE)) or a next generation Node B (gNB in 5G NR (Fifth Generation New Radio)). The base station 110 may typically be controlled by at least one appropriate controller apparatus (not shown), so as to enable operation thereof and management of UEs 120 A / B / C in communication with the base station 110. The controller apparatus may be located in a radio access network (e.g. the wireless communication system 100) or in a core network (CN) (not shown) and may be implemented as one central apparatus or its functionality may be distributed over several apparatus. The controller apparatus may be part of the base station and / or provided by a separate entity such as a Radio Network Controller. Instead of a base station, the system 100 may employ a suitable device such as a relay, an access point, a remote radio module, radio header, a remote radio head, a low power node such as a femto, pico, and the like.

[0052] The base station 110 may have a plurality of antenna to deploy or implement SU-MIMO (single- user MIMO) and MU-MIMO modes, and can schedule resources for the UE 120 using the various modes. In the SU-MIMO mode, multiple data streams are directed towards individual wireless devices. In the MU-MIMO mode, the multiple data streams can be directed towards plural wireless devices (e.g., UE 120) that are selected to participate in the MU-MIMO mode based on the orthogonality of transmission. MU-MIMO technology may allow spatially distributed users to share the same network resources — simultaneously — using MU pairing. When MU-MIMO is used, the same physical resource block (PRB) resource can be assigned or reused to multiple user equipment (e.g., UE 120A and UE 120B).

[0053] The base station 110 can comprise a processor and associated circuitry to execute or direct the execution of computer-readable instructions to perform operations such as those further described herein. Briefly, the base station 110 can retrieve and execute software from storage, which can include a disk drive, a flash drive, memory circuitry, or some other memory device, and which can be local or remotely accessible. The software may comprise computer programs, firmware, or some other form of machine-readable instructions, and may include an operating system, utilities, drivers, network interfaces, applications, or some other type of software, including combinations thereof. Further, the base station 110 can receive instructions and other input at a user interface. For the purpose of discussion and in some example embodiments, the system 100 includes the base station 110.

[0054] The UE 120 can be any device that is capable of sending and receiving radio signals. Non-limiting examples of the UE 120 comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, machine type devices or any combinations of these or the like.

[0055] As previously disclosed herein, the base station 110 may dynamically allocate PRBs for each UE that it is serving. A basic description of the PRB structure of an LTE (Long Term Evolution), LTE- A (Long Term Evolution-Advanced), and 5G NR (Fifth Generation New Radio) system will be provided herein. The PRB may represent a basic structure of a time-frequency resource region representing a radio resource region for transmitting data or control channel in an LTE, LTE-A, and NR system employing a cyclic prefix (CP) OFDM (orthogonal frequency division multiplexing) (CP-OFDM) or SC-FDMA (single carrier frequency division multiplexing) waveform. The PRB structure may have a time domain and frequency domain. The time domain may be represented by symbols (e.g., SC-FDMA symbols) and the frequency domain may be represented by subcarriers. In LTE and LTE-A, two slots (each having 7 symbols) form a subframe. In 5G, the length of a slot or a mini-slot may vary with subcarrier spacing, unlike in LTE and LTE-A where a slot has a fixed length of 0.5 ms and a subframe has a fixed length of 1.0 ms. In LTE and LTE-A, a subcarrier may have a spacing of 15 kHz in the frequency domain.

[0056] The communications in the system 100 may conform to any suitable standards, including, but not limited to, Global System for Mobile Communications (GSM), Extended Coverage Global System for Mobile Internet of Things (EC-GSM-IoT), Long Term Evolution (LTE), LTE-Evolution, LTE- Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), and the like.

[0057] Furthermore, the communications in the system 100 may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but are not limited to, the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G) communication protocols. The base station 110 may comprise a scheduler that is responsible for PRB allocation. The uplink scheduler may determine the amount of data in buffer for each UE 120, and then determine the number of physical resource blocks (PRBs) required to be assigned to the UEs 120A / B / C to drain the buffer.

[0058] It is to be understood that FIG. 1 depicts only one base station 110 and three UEs 120 for the purpose of illustration / sake of simplicity, without suggesting any limitations. The base station 110 and the UEs 120A / B / C may be located within a boundary 130, wherein the inside of the boundary represents the cell coverage area. This boundary may also be referred to as “cell edge.” As used herein, the term “cell” refers to an area covered by radio signals transmitted by the base station 110. The user equipment 120 within the cell may be served by the base station 110 and access the communication network via the base station 110.

[0059] Based on FIG. 1, it can be seen that the UEs 120 A / B are located near the base station 110, whereas the UE 120C is located at the cell edge (and is further away from the base station compared to the UEs 120A / B). UE 120C can be considered as a power-limited UE as it would have reached its maximum transmit power limit owing to its location. On the other hand, the UEs 120A / B, are closer to the base station. Therefore, the UEs 120A / B can be considered as non -power-limited UEs.

[0060] Assuming similar QoS (Quality of Service) requirements, scheduling weights and buffered data among the UEs 120A / B / C, a drawback with the uplink scheduler (in the base station 110) assigning an equal distribution of PRBs to UEs 120 A / B / C without considering the transmit power limitations of each UE is that it can to sub-optimal PRB utilization. In other words, assigning a power-limited UE (e.g., UE 120C) with the same number of PRBs that are assigned to a non- power-limited UE (e.g., UE 120A / UE 120B) can hurt system performance, as it can result in lower modulation and coding scheme (MCS) and lower spectral efficiency (SE).

[0061] Similarly, PRB allocation to UEs 120 A / B / C in MU-MIMO has its own problems. In MU-MIMO, the scheduler attempts to explore MU-MIMO pairing between UEs 120A / B / C. The UE (e.g., UE 120A / 120B) having the highest PRB requirements may be selected as the first UE in a pair. However, the second UE (e.g., 120C) in the pair may be a power limited UE, which may lead to power spectral density (PSD) reduction. Any further pairing to the power limited UE can result in higher interference and reduced performance.

[0062] Accordingly, example embodiments in the present disclosure take into consideration the UE’s maximum transmit power limit to improve the throughput and over-the-air performance of UEs. Some example embodiments disclosed herein take into account the number of PRBs at which the UE’s 120 maximum transmit power limit is reached. In other words, by determining the number of PRBs at which the UE’s 120 maximum transmit power limit is reached, any excessive PRB allocation to the UE 120 can be avoided. This can result in improvement in the uplink spectral efficiency and capacity of the cell.

[0063] In example embodiments disclosed herein, SU-MIMO (single -user-multiple-in-multiple-out) mode and MU-MIMO (multi-user-multiple-in-multiple-out) mode are implemented.

[0064] The PRB allocation methods utilized by some of the example embodiments, restrict the PRB allocation of power-limited UEs (e.g., UE 120C) to a smaller number of PRBs such that a larger power spectral density (PSD) value or higher power per PRB can be achieved. The remaining PRBs can be allocated for the non-power-limited UEs (e.g., UEs 120A / B) that can use a higher MCS, thereby achieving a better system level spectral efficiency and throughput performance.

[0065] FIG. 2 illustrates the sequence of PRB allocation to at least one UE 120, according to an example embodiment of the present disclosure. In FIG. 2, it is shown that there can be three rounds (Round 1, 2, and 3) of scheduling that can involve PRB allocation. Prior to the three rounds, time division scheduling may occur so that the number of UEs 120, for which PRBs have to be allocated to, can be determined. The following is a brief description of the various rounds of scheduling (which include PRB allocation).

[0066] In Round 1 scheduling, with SU-MIMO, the UEs 120 may be allocated with the PRBs without PSD reduction. In other words, in Round 1, the UEs may be allocated with PRBs based on their maximum transmit power limit. Here, the PRBs may be distributed in a round robin fashion to individual UEs such that the PSD limit is not compromised for any UE. In some example embodiments, there can be a weighted round-robin allocation of PRBs, where the weights could be a function of the QoS (Quality of Service) needs of the UE. At the end of Round 1 scheduling, if the number of PRBs that are required by the UEs 120 are not met, then Round 2 of PRB allocation may begin. In other words, if the UEs 120 can be allocated with additional PRBs (i.e., utilizable PRBs) before their maximum transmit power limit is reached, then they may be allocated with the utilizable PRBs in Round 2.

[0067] In Round 2 scheduling, uplink MU-MIMO may be implemented to achieve spatial division multiplexing (SDM), which can allow for PRB allocation to UEs on the same time -frequency resources (i.e., UE pairing). In other words, the paired UEs may reuse the PUSCH (physical uplink shared channel) resources. The spatial division (SD) scheduler — which may be present in the base station 110 — may decide dynamically which UEs 120 can share resources in a given slot. The maximum supported spatial layers by the SD scheduler may be denoted by Lmax. This limit may be reached by various scenarios including pairing different number of UEs and different number of layers or rank per UE such that the sum of layers across the paired UEs is capped at Lmax. For the sake of simplicity, it may be assumed that each UE has only one layer, which can mean that for each additional spatial layer, the SD scheduler may explore adding another UE to the existing paired UEs. In Round 2, the SDM may be carried out in multiple iterations, and the number of UEs paired in each iteration may be denoted by the UE pair index I. Starting from 1 = 2, the UE pair index I may be incremented for each iteration up to I = Lmax.

[0068] Round 3 scheduling occurs if there are remaining PRBs (i.e., not all the PRBs in a system are exhausted) after Round 1 and Round 2 of scheduling. In Round 3, the PRBs may be allocated to the UEs 120 in a manner where PSD reduction can occur. In other words, in Round 3, the PRB allocation to the UEs 120 may occur irrespective of the UE’s maximum transmit power limit. In Round 3, the PRBs may be distributed in round robin fashion to the eligible UEs, such that the TBS (Transport Block Size) for the UEs 120 increase as a result of the additional PRBs allocated in this round. It is to be noted that although some example embodiments allocate PRBs for Round 1 (with SU- MIMO) and Round 2 (with MU-MIMO) in a spectrally efficient and fair manner amongst all types of UEs (power-limited and non-power- limited), the PRB allocation for Round 3 may be done in a manner that results in a lower PSD for the UE 120. One rationale for this may be that if — after Round 1 and Round 2 of scheduling — there are eligible UEs that are unable to utilize the available bandwidth (i.e., remaining PRBs after Round 1 and 2 scheduling), then it may be better to distribute the remaining PRBs to the eligible UEs (despite resulting in lower PSD) because the loss due to leaving PRBs may be larger compared to the loss from using a lower PSD.

[0069] FIG. 3 illustrates a flowchart for the various rounds of scheduling, according to some example embodiments disclosed herein. At step 302, TD scheduling may be performed to select ‘N’ UEs based on their control channel capacity. The value of N can represent the maximum number of UEs that can be scheduled in uplink. This value may be a consequence of PDCCH (physical downlink control channel) limits or hardware constraints.

[0070] At step 304, the number of PRBs (Remaining PRBs) can initialized, with the value being calculated as follows:

[0071] RemainingPRBs = Function (System BW, SCS), (eq. 1) where

[0072] “System BW” represents the system bandwidth, and “SCS” represents the subcarrier spacing.

[0073] In one embodiment, the RemainingPRBs can be determined based on Table 5.3.2- 1 of 3GPP (Third Generation Partnership Project) TS (Technical Specification) 38.101-1 V17.10.0.

[0074] Also at step 304, the number of UEs (RemainingUEs) can be initialized, with the value being equal to N (determined at step 302). At step 306, for UEi where z=l ...N, the following metrics may be calculated: a) For the configured Po(pre-configured power) and a (path loss correction factor), the scheduler may compute for UEi, for its current estimated pathloss PathLossi, the maximum transmit power (in uplink) it can achieve per PRB. This is denoted as and the maximum number of PRBs it can transmit with that transmit power is denoted as represents the maximum transmit power for the UE power class. Assuming the other terms such as closed-loop power control, and Sare zero, PSD_PRBi may be computed as:

[0075] The uplink transmit power and the power per PRB may be in dB scale. b) For each UEi, the scheduler (in the base station 110) may compute the number of PRBs at which the TBS is maximized. This may typically occur when transmission with MCS 0 is still sustainable. This is denoted as PRB_nTBSi.

[0076] Round 1 scheduling:

[0077] At step 308, the N UEs may be sorted in the ascending order of their PRB_nMCSi (maximum number of PRBs without compromising the PSD). As a result, UE1may have the lowest whereas UENmay have the highest PRBjiMCS.

[0078] At step 310, based on the sorted list of UEs, the number of PRBs to be assigned to each UE in Round 1 scheduling may be calculated. In Round 1, the PRBs may be allocated to the UEs without compromising on the PSD. The number of PRBs to be assigned may be calculated as follows:

[0079] At step 312, the number of PRBs actually distributed to the UEs may be calculated as follows: CurrentAllocationJJEi = min fRoundlAllocation_UEi, PRB_nMCSf) (eq. 5)

[0080] At step 314, after allocation to UEj, RemainingPRBs and RemainingUEs are updated as: RemainingPRBs = RemainingPRBs — CurrentAllocationJJEi (eq. 6)

[0081] The following is an example of Round 1 scheduling. Assume that there is UE±and UE2with 20 PRBs. Assume that PRB_nMCS1is 4 and PRB_nMCS2is 5.

[0082] In some of the example embodiments, it may be assumed that all the UEs have the same QoS requirements, and hence scheduler weight class. For embodiments where there are different QoS requirements, normalized scheduler weights (own UE’s weight to sum of all UEs’ weights) may be used for PRB allocation. The total PRB resources that can be allocated to all N UEs without PSD reduction may be computed as

[0083] At step 316, after Round 1 scheduling, the scheduler may check evaluate the necessity for spatial division multiplexing (SDM) (i.e., Round 2 scheduling). This evaluation may be performed by checking if In other words, the scheduler may check if the required number of PRBs (i.e., maximum number of PRBs that can be allocated to a UE without compromising on PSD) is greater than the number of allocated PRBs. If the required number of PRBs is greater than the number of allocated PRBs, then it may mean that there is at least one utilizable PRB, and that SDM can be performed.

[0084] If yes, then at step 318, the current PRB allocation can be expanded further with MU-MIMO without sacrificing the PSD, and the scheduler may proceed to Round 2 to explore UE pairing from SDM and combined PRB allocation to paired UEs.

[0085] If no, then at step 320, it is checked if RemainingPRBs > 0. If the value is greater than zero (i.e., there still are unused PRBs in the system), then at step 322, the scheduler may proceed directly to Round 3 to distribute the RemainingPRBs to all the UEs by PRB allocation with PSD reduction. If RemainingPRBs is zero, then that would mean that the available system bandwidth is now completely utilized by the UEs (i.e., all the PRBs have been exhausted).

[0086] Round 2 Scheduling:

[0087] Round 2 of scheduling will now be explained in greater detail. As previously stated herein, in Round 2, SDM may be explored by pairing those UEs which would benefit from mutual sharing of their respective PRB allocation in Round 1. In some example embodiments, a UEi may be eligible for SDM and additional PRB allocation (i.e., utilizable PRB allocation) in Round 2, if its PRBjiMCSi > Current AllocationJJ Ei. Stated differently, for a UE) to be eligible for SDM, the number of PRBs allocated to it (in Round 1) may need to be lower than its required number of PRBs (i.e., the maximum number PRBs that can be allocated to it without compromising on PSD). Alternatively, in other example embodiments, Roundl_Uni formAllocation or a pre-configured threshold can be used for determining the eligibility for SDM.

[0088] Among N UEs from Round 1, there may be UES eligible for Round 2. The eligible UEs may be present in a list (referred to as “MUlistRound2”). For each UE in the MUlistRound2 list, the additional PRBs required (i.e., utilizable PRBs) to meet each UE’s PRB requirement may be estimated by computing the difference between its PRB_nMCSi and its allocation in Round 1, given by: where,

[0089] PRBrequiredi represents the number of remaining PRBs required by the UEi,

[0090] PRB_nMCSi represents the maximum number of PRBs that can be allocated to the UEi without compromising on its PSD, and

[0091] Current AllocationJJ ELrepresents the number of PRBs that were allocated to UEi (inRound 1).

[0092] Then, the UEs in the MUlistRound2 list may be sorted in the descending order of the PRBrequiredi. Stated differently, the first UE in the list will be the UE having the highest value of PRBrequiredi, whereas the last UE in the list will be UE having the lowest value of PRBrequiredi.

[0093] Round 2 Scheduling: SDM UE Pairing

[0094] In Round 2, UE groups (UEG) may be introduced to enable UE pairing and PRB allocation. As the scheduler may explore SDM incrementally for every higher UE pair index I, the UEG may facilitate PRB allocation of paired UEs in a unified manner. The UEG is an entity that can have one UE or multiple paired UEs. The UEG may be given a combined PRB allocation over one set of PRBs. The set of all UEGs may be represented as SUEG, where SUEG= {Sk}. Skcan be represented as: Sk= {U Ey], which may correspond to a UEG. The entries of Skmay be a single UE or paired UEs.

[0095] After SDM at UE pair index I, a UEG can be of size varying between 1 (i.e., UEG containing single UE without pairing) and size I (i.e., UEG containing I paired UEs each served by different spatial beams), i.e., 1 < |Sk| < I. PRB_nMCSSkmay correspond to the maximum PRB_nMCS among the paired UEs in the UEG Skand PRB_budget_UEGSkmay represent the current PRB allocation for the UEG Sk.

[0096] Initializing UE pair index to I = 1 and SUEG={}, there may be / Vs DM UEGS that are created, wherein each UEG has a single UE from the MUlistRound2 list. Each of the 1VSDMUEGs may be added to the set SUEGin the same sorted order. For UEG Sk, PRBjiMCSSk= PRBjiMCSi and PRB_budget_UEGSk= Current Allocation^ ELwhere I 6 Sk. At the start of Round 2 (i.e., when UE pair index I = 1), the number of UEGs in the set SUEGis 1VSDM.

[0097] In Round 2, the SDM may begin by incrementing the UE pair index to I = 2. For two UEGs, Smand Sn, that are paired, a new UEG Skis created, wherein its entries are the UEs from Smand Sn. In other words, Sk= SmU Sn. The UEGs Smand Snmay then be removed from the set SUEGand the new UEG Skis added to SUEGand this would result in the number of UEGs in the set SUEGreduced by one. For UEG Sk, PRB_nMCSSk= max PRBjiMCSi i-e., the maximum of PRBjiMCS among all the paired UEs, and PRB_budget_UEGSk= PRB_budget_UEGSm+ PRB_budget_UEGSnmay be the current PRB allocation.

[0098] For example, assume that there is UEG1(having UE^ and UEG2(having UE2). Also assume the following values:

[0099] For UE1,

[0100]

[0101] The previous number of total UEGs was 2 fUEG1and UEG2) and after pairing, the total number of UEGs has reduced by one (i.e., only UEG12remains).

[0102] For UE pair index Z = 2 , all the UEGs may contain only a single UE; hence up to two UEGs can be paired. Starting with the first UEG in SUEG, spatial multiplexing may be explored by finding another UEG such that the spatial correlation between the UEs in both the UEGs are below the configured correlation threshold (an example of an orthogonality criteria). In other words, upon computing the spatial correlation between the UEs, if it is higher than the correlation threshold, then those UEs may not be paired. However, if the spatial correlation is lesser than the correlation threshold, then pairing between the UEs is possible. The value for the correlation threshold may be obtained by numerical simulations.

[0103] If pairing is possible, then those two UEGs with one UE each may be merged to form a single UEG containing two paired UEs. This pairing procedure may be repeated with the remaining UEGs in SUEGfor further two pairing opportunities. Hence, after exploring SDM, the number of UEGs may be given by |SUEG| < ZVSDM. After exploring SDM for Z = 2, if |SUEG| < 1VSDM, then the scheduler may proceed to PRB allocation for those. If |SUEG| = 1VSDM, then that could mean that no SDM was possible among the ZVSDMUEGs, and the scheduler stops Round 2 and concludes the PRB allocation. For UE pair index I > 2 , if required, the scheduler may explore for SDM with one higher UE pair index (i.e., one more UE added to the UEGs). At every higher UE pair index, the scheduler may explore the possibility of SDM of any existing UEG with another UEG by checking if the spatial correlation between all the UEs within both the UEGs are below the correlation threshold and the total number of UEs in both the UEGs is equal to I. If yes, the UEs are paired and the two UEGs are merged to form a single UEG with I constituting UEs from both the UEGs. Hence the number of entries in the set SUEGis reduced by one and the two UEGs are replaced with one merged UEG. A similar process is carried out for every UE pair index I up to the maximum allowed Lmaxspatial layers as shown in FIG. 4

[0104] FIG. 5 illustrates a flowchart for implementing SDM UE pairing, according to example embodiments disclosed herein. The method 500 may be implemented by the base station 110.

[0105] At step 502, the list of UE candidates for SDM are determined for Round 2 scheduling may be determined. The list of candidates may be those UEs whose allocated number of PRBs is lesser than the number of required PRBs (i.e., PRBs at which the UE reaches its maximum transmit power limit).

[0106] At step 504, the UE candidates may be sorted in descending order of a predefined metric. This predefined metric can be the number of required PRBs for each candidate UE. Also, at step 502, the UE pair index I may be initialized to 1.

[0107] At step 506, the UE pair index may be incremented (for example, from I = 1 to I = 2) and SDM for the for the current UE pair index may be proceeded with.

[0108] At step 508, UE pairing may be explored using an orthogonality criteria.

[0109] At step 510, after the pairing of the UEs (to create at least one UE pair) at the current UE pair index, the combined PRB allocation for a UE pair may be the sum of the total number of allocated PRBs to each UE in the UE pair. At step 512, any freed PRBs (as a result of the UE pairing), may be allocated to other UE pairs that have a higher PRB requirement.

[0110] At step 514, after completing SDM and PRB allocation in the current UE pair index I, candidates for further pairing may be those UEs for whom the latest PRB allocation is less than PRB_nMCSi .

[0111] At step 516, if further SDM is not required, then, it may be the end of Round 2 scheduling.

[0112] If further SDM is required, then at step 518, it is checked if the UE pair index has reached its maximum value. If not, then the steps from step 506 onwards may be repeated. Otherwise, it may be the end of Round 2 scheduling.

[0113] In some example embodiments, this correlation threshold can be configured. It is to be noted that the term “UE pair” can mean two or more UEs that are paired with each other.

[0114] Further details about the PRB allocation in Round 2 scheduling will now be described.

[0115] Round 2 Scheduling: PRB Allocation for UEG

[0116] After SDM, combined PRB allocation may be carried out for every UEG with size more than one by allocating the sum of the Round 1 allocation of constituent UEs within the UEG.

[0117] In some of the example embodiments, two PRB allocation methods may be utilized. The allocation method that is chosen may be based on the requirement of the receiving at the base station to have either fully overlapping or partially overlapping PRB allocation among the paired UEs in a UEG, as shown in FIGS 6A and 6B.

[0118] PRB allocation-Method 1 : The first proposed PRB allocation method may allow for partially- overlapping PRB allocation among the paired UEs in a UEG. The combined PRB allocation of the UEG Skmay be restricted to: where,

[0119] PRB_budget_UEGSkis the combined PRB allocation for the UEGSk, which can be calculated as the minimum of max PRB nMCS, or the sum of Round 1 PRB allocations to each UE in UEGc, . i<ESk~ max PRB_nMCSi may represent the maximum number of PRBs that can be allocated to a UE in

[0120] UEGsk-

[0121] In other words, within the UEG, each paired UE’s allocation may be limited by mm(PRB_nMCS of that UE, PRB_budget_UEGSk). This method may only use PRB_nMCS value of each paired UE, and could result in partially-overlapping PRBs across the paired UEs within a UEG. The above allocation could result in the combined PRB allocation of the UEG limited by the largest of the PRB_nMCS. If the PRB_budget_UEGSkof a UEG Skis less than the sum of the Round 1 PRB allocations (this may imply that the largest PRBjiMCSi in the UEG Skis less than the sum of the Round 1 PRB allocations).

[0122] For example, let there be UEGSkhaving two paired UEs (U^and UE2). Assuming UE1and UE2have the following details:

[0123] PRB_nMCS1= 7 PRB_budget_UE1= 4

[0124] PRB_nMCS2= 9 PRB_budget_UE2= 6

[0125] Here, the maximum number of PRBs that can be allotted to UE1is 7, and the maximum number of PRBs that can be allotted to UE2is 9. Therefore, in UEGSkcomprising UE1and UE2, the value of maxPRB_nMCSi is 9. iesk In Round 1, UE1was allocated with 4 PRBs and UE2was allocated with 6 PRBs. The sum of Round 1 allocations for UEGSkis 10.

[0126] Therefore, on inputting the above values in equation 9, and so, 9 PRBs may be allocated for UEGSkin the PRB allocation method 1.

[0127] The extra PRBs beyond the requirement of the UEG may be computed as: additionalPRBs_UEGSk= Z ' i&skRoundlAllocation_UEi— PRB_budget_UEGSk(eq. 10)

[0128] Inputting the values of the previous example in equation 10, the extra PRBs may be computed as: additionalPRB s_U EGSk= [(4 + 6) — 9] = 1

[0129] Therefore, there is 1 additional PRB.

[0130] If there are any unutilized PRBs (i.e., if additional / 1RBs_UEGSk> 0), they may be distributed to other UEGs whose PRB allocation PRB_budget_UEGSkis limited by the sum of the Round 1 allocations of their paired UEs (i.e., those UEGs with max PRB nMCSj > iesk

[0131] £ieSfeRoundlAllocationJJEi).

[0132] FIG. 7 illustrates a method 700 for allocation of partially-overlapping PRBs to paired UEs, according to some example embodiments disclosed herein. The method 700 may be implemented by the base station 110. At step 702, a first UE pair comprising at least two UEs, may be allocated with a number of PRBs that is equal to minimum of the following parameters: a) the largest number of PRBs that can be allocated to the at least two UEs when their respective transmit power limit is reached; or b) the total number of PRBs that have been allocated to the at least two UEs.

[0133] For parameter ‘a’, the respective transmit power limit of the UE can be its maximum transmit power limit. Based on the maximum transmit power limit of the respective UE, if the largest number of PRBs that can be allotted to UE1is 7, and the largest number of PRBs that can be allotted to UE2is 9, then the value to be computed for parameter ‘a’ is 9.

[0134] For parameter ‘b’, the value computed can be the total number (i.e., sum) of resource blocks that have been allocated to the at least two UEs during PRB allocation with SU-MIMO (i.e., Round 1 of scheduling).

[0135] At step 704, it is determined that there are one or more unutilized PRBs by the first UE pair. In other words, there may be one or more unutilized PRBs that can be distributed to other UE pairs. The availability of these utilized PRBs may be based on the number of PRBs that are allocated to the first UE pair being lesser than the parameter ‘b’. In other words, the availability of the unutilized PRBs can be based on the UE pair being allocated with PRBs having a value of parameter ‘a’.

[0136] At step 706, at least one other UE pair comprising at least two UEs, is allocated with the one or more unutilized PRBs.

[0137] PRB allocation-Method2: The second PRB allocation method for a UEG may result in fully overlapped PRB allocation among the paired UEs. The combined PRB allocation of UEG Skis restricted to: In this method, the PRB allocation of all the paired UEs may be the same as the UEG’s combined PRB allocation, and could result in strict (i.e., complete) overlapping of PRBs across the paired UEs. This method can use both PRB_nMCS and PRB_nTBS (the number of PRBs at which the Transport Block Size is maximized) values of all the UEs in the paired UEG. The above PRB allocation could result in restricting the PRB allocation of the paired UEs to the above computed value, which could be less than even some of the paired UE’s PRB_nMCS. This is done so that fully overlapped allocation can be maintained, and so that it can be ensured that the PRB_nT BS — of any of the UEs in the UEG — is not exceeded.

[0138] For example, let there be UEGSkhaving two paired UEs (t / ^and UE2). Assuming UE1and UE2have the following details:

[0139] PRB_nMCS1= 7

[0140] PRB_nTBS1= 6

[0141] PRB_budget_UE1= 4

[0142] PRB_nMCS2= 9

[0143] PRB_nTBS2= 7 PRB_budget_UE2= 6

[0144] Here, the maximum number of PRBs that can be allotted to UE1is 7, and the maximum number of PRBs that can be allotted to UE2is 9. Therefore, in UEGSkcomprising UE1and UE2, the value of max PRB nMCSj is 9. iesfe

[0145] For UE1, the TBS is maximized at 6 PRBs. For UE2, the TBS is maximized at 7 PRBs. Therefore, minPRBjiTBSj is 6. iesfe

[0146] In Round 1, UE1was allocated with 4 PRBs and UE2was allocated with 6 PRBs. The sum of Round 1 allocations for UEGSkis 10. On inputting the above values in equation 11 , we get

[0147] PRB_budget_UEGSk= min(9, 6, 10), and so, 6 PRBs are allocated to UEGSkin the PRB allocation method 2.

[0148] FIG. 8 illustrates a method 800 for allocation of fully overlapping PRBs to paired UEs, according to some example embodiments disclosed herein. The method 800 may be implemented by the base station 110.

[0149] At step 802, a first UE pair comprising at least two UEs, may be allocated with a number of PRBs that is equal to minimum of: a) the largest number of PRBs that can be allocated to the at least two UEs when their respective transmit power limit is reached; b) the smallest number of PRBs that can be allocated to the at least two UEs when their respective Transport Block Size has reached its maximum value; or c) the total number of PRBs that have been allocated to the at least two UEs.

[0150] For parameter ‘b’, if UE1reaches its maximum Transport Block Size (TBS) when allocated with 6 PRBs, and UE2reaches its maximum TBS when allocated with 7 PRBs, then the value that is computed for parameter ‘b’ is 6.

[0151] At step 804, it may be determined that there are one or more available PRBs. The availability of the one or more PRBs may happen if the number of PRBs being allocated to the first UE pair has a value of parameter ‘a’ or ‘b’.

[0152] At step 806, the one or more available PRBs may be allocated to at least one other UE pair comprising at least two UEs.

[0153] After combined PRB allocation for UEGs with any of the PRB allocation methods above, there could be some UEGs whose sum of the Round 1 allocations of its paired UEs is more than the maximum required PRBs PRB_nMCSSk. As a result, the number of PRBs freed by the UEGs in UE pair index I may be accumulated in RemainingPRBs. For every UE pair index I, the following may happen: i) re-initialize RemainingPRBs = 0 and ii) accumulate the number of PRBs freed by the UEGs as given by

[0154] RemainingPRB = RemainingPRB + additionalP RBs_UEGSk(eq. 12)

[0155] Similarly, after combined PRB allocation for UEGs, there could be some UEGs whose sum of the Round 1 allocations of its paired UEs is less than PRB_nMCSSk. Additional PRBs required by a UEG Skmay be given by PRB_nMCSSk— PRB_budget_UEGSk. For UE pair index I, RemainingUEG may be the number of UEGs for whom their current PRB allocation is not yet sufficient (i.e., PRB_nMCSs. — PRB_budget_UEGs. > 0).

[0156] In Round 2, if RemainingPRB > 0 and RemainingUEG > 0, then the freed RemainingPRB PRBs may be distributed among UEGs such that power spectral density or power per PRB is not compromised in the next step.

[0157] Round 2 Scheduling: PRB sharing between UEGs

[0158] In some example embodiments, two PRB resource sharing methods may be utilized for the distribution of the freed PRBs to those eligible UEGs whose PRB requirements are not yet met. In other words, PRB sharing between UEGs may occur for those UEGs that require additional PRB allocation.

[0159] PRB sharing-Method 1: In this first PRB sharing method, the PRBs freed may be distributed in a fair and equitable manner amongst all the eligible UEGs. a) Sort UEGs in the ascending order of additional PRBs required i.e., PRB_nMCSSk— PRB_budget_UEGSkb) For each UEG Skin the above sorted order: P

[0160] The following example illustrates the first PRB sharing method. Assume that for UEGS1comprising UE1and UE2, and for UEGSscomprising UE3and UE4the following values are present:

[0161] For UE1(belonging to UEGS1):

[0162] PRB_nMCS1= 7

[0163] PRB_budget_UE1= 2

[0164] For UE2(belonging to UEGS1):

[0165] PRB_nMCS2= 12

[0166] PRB_budget_UE2= 6

[0167] For UE3(belonging to UEGSs):

[0168] PRB_nMCS3= 8

[0169] PRB_budget_UE3= 2

[0170] For UE4(belonging to UEGSs):

[0171] PRB_nMCS4= 13

[0172] PRB_budget_UE4= 6 For UEGS1, the additional PRBs required can be calculated by PRB_nMCSSk—

[0173] PRB_budget_UEGSk, namely [(max (7, 12)) - (6+2)], which is equal to 4.

[0174] For UEGSs, the additional PRBs required can be calculated by PRB_nMCSSk—

[0175] PRB_budget_UEGSk, namely [(max (8, 13) - (6+2)], which is equal to 5.

[0176] The number of PRBs remaining can be calculated as 4+5, which is equal to 9.

[0177] Performing the same calculations for UEGSs, it can be seen that 5 PRBs are added to the budget of UEGS.

[0178] PRB sharing-Method2: In this second PRB sharing method, the PRBs freed may be distributed in a spectrally efficient manner, starting with the eligible UEG that has the maximum utilization from getting additional resources. Any remaining PRBs may be sequentially distributed to other UEGs in the descending order of their utilization benefit from the additional PRBs.

[0179] In the second PRB method, PRB_BenefitMetricSkcaptures the PRB utilization benefit to each of the UEG Skfrom getting an additional PRB. It may be computed as the ratio of aggregate additional PRBs required among each of the paired UEs in the UEG Skand the number of additional PRBs required to meet the overall demand of the UEG Sk, given by where 1 < PRB_BenefitMetricSk< |Sk| for the UEG Sk.

[0180] In the second PRB sharing method, a) The RemainingUEG UEGs may be sorted in the descending order of their PRB_BenefitMetricSk, and b) For each UEG Skin the above sorted order and if RemainingPRB sSDM> 0:

[0181] PRBs_used = min (PRB_nMCSSk— PRB_budget_UEGSk, RemainingPRBs_SDM>) (eq. 19) PRB_budget_UEGSk= PRB_budget_UEGSk+ PRBs_used (eq. 20)

[0182] RemainingPRB = RemainingPRB — PRBs_used (eq. 21)

[0183] For every UE pair index I, after SDM and PRB allocation are completed, the Current AllocationJJ Etof each UE i in the UE list of MUlistRound2 may be updated as: where, UE i E UEG Sk.

[0184] For any UE pair index I, after SDM and PRB allocation, if the freed PRBs by the UEGs are not fully exhausted (i.e., RemainingPRB > 0), then the scheduler may conclude Round 2 and proceed to Round 3 to distribute the remaining PRBs to all the eligible UEs by PRB allocation with PSD reduction. In other words, in Round 3, the scheduler may distribute the remaining PRBs to the eligible UEs regardless of their respective PRB_nMCS value.

[0185] After exploring SDM of two UEs and PRB allocation for Z = 2, if Remaining PRB = 0, then the scheduler may evaluate the necessity for doing further SDM by checking if PRB_nMCSi >

[0186] If yes, then the scheduler may increment the UE pair index to Z = 3, and repeat the previously disclosed SDM pairing, PRB allocation, and PRB sharing methods.

[0187] As illustrated in FIG. 5, after SDM and PRB allocation for every UE pair index I, a similarly evaluation may be done to determine the need for further SDM and if required, the scheduler may increment the UE pair index I till I = Lmaxis reached. After that the scheduler stops to conclude Round 2.

[0188] Round 3 Scheduling Method:

[0189] In Round 3, the scheduler may proceed with additional PRB allocation with PSD reduction (i.e., current PRB allocation of the UEs can be expanded further by lowering the PSD such that the TBS is maximized) only if the PRBs are not exhausted after Round 1 and Round 2 (i.e., if RemainingPRB > 0). Remaining PRBs may be distributed in a round robin fashion such that all of N eligible UEs can get PRB allocation in Round 3.

[0190] After Round 1, there may be (N — NSDM) UEs that did not participate in Round 2. In other words, the UEs that did not participate in Round 2 may be the UEs that were not present in the list MUlistRound2. The (N — ZVSDM) UEs may make it to the UE List of " U El istRoundS" . Among the AZSDM UES in Round 2, those UEs with its Current AllocationJJ EL= PRB_nTBSi and all its paired UEs may not be added to UElistRound3. The other UEs from Round 2 may make it to UElistRound3.

[0191] In Round 3, a) the UEs may be sorted in ascending order of PF (proportional fairness) metric or equivalent scheduling metric, b) the RemainingUEs may be initialized to the number of entries in the UE list UElistRound3, and c) the below steps may be performed until all PRBs are exhausted.

[0192] For each UE in UE List of UElistRound3:

[0193] AllocatedPRBs = min (^Round3U EShare, PRB _nTBS — CurrentAllocationJJE} (eq. 25)

[0194] RemainingPRBs = RemainingPRBs — AllocatedPRBs (eq. 26)

[0195] RemainingUEs = RemainingUEs — 1 (eq. 27)

[0196] The Transport Block Size (TBS), allocated PRBs, and MCS may be updated in the UE context.

[0197] FIG. 9 is a simplified block diagram of a device 900 for implementing the example embodiments of the present disclosure. The device 900 is an example of a device that may be configured to implement the various methods and processes described herein. The device 900 may be a network device (e.g., the base station 110) or a terminal device (e.g., the UE 120).

[0198] The device 900 comprises a processor 904 which can control the device’s operations. The processor 904 may also be referred to as a central processing unit (CPU). The memory 902, which may include both read-only memory (ROM) and random access memory (RAM), can provide instructions and data to the processor 904. The memory 902 and the processor 904 may be operatively coupled. The memory 902 may store computer readable instructions / computer program code. The computer readable instructions / computer program code may be pre-stored to the memory 902 or, alternatively or additionally, they may be received, by the device 900, via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions by the processor 904, can cause the device 900 to carry out the example embodiments described herein. In the context of this document, a “memory” (also referred to as “computer-readable media” or “computer-readable storage medium”) may be any non-transitory media or medium or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The term “non- transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0199] The transmi tter / receiver (TX / RX) circuitry 908 may comprise a transmitter 910 and a receiver 912 that can enable the device 900 to transmit or receive data. The device 900 may comprise (not shown) multiple antennas, transmitters, and receivers that enable it to be suitable in a MU-MIMO system.

[0200] In example embodiments where the device 900 is a network device (e.g., the base station 110), it can comprise a scheduler 906 to help it with allocating resource blocks to the terminal device (e.g., the UE 120). The scheduler 906 can be operatively coupled to the processor 904. The scheduler 906 can be a TD and / or SD scheduler. In some embodiments, the scheduler 906 can be a part of the processor 904, and therefore, the various actions performed by the scheduler (as described herein) can be attributed to the processor 904 of the network device (e.g., the base station 110).

[0201] FIG. 10 illustrates a method 1000 performed by a base station 110, according to an example embodiment of the disclosure herein. The steps in method 1000 may relate to the scheduling of a plurality of UEs in a wireless communication network.

[0202] At step 1002, the base station may select a group of UEs within the plurality of UEs. In other words, only a subset of UEs present in the wireless communication network may be selected for scheduling. In one embodiment, the group of UEs may be selected based on their control channel capacity (e.g., PDCCH (physical downlink control channel) limit). At step 1004, the base station 110 may obtain a scheduling metric for each UE in the selected group. An example of the scheduling metric can be PRB_nMCS, i.e., the maximum number of PRBs at which the UE achieves its maximum transmit power limit.

[0203] At step 1006, the base station 110 may determine a set of PRBs for the selected group of UEs, based on the scheduling metric. In other words, this set of PRBs can relate to the PRBs that are to be allocated to the subset of UEs, i.e., the UEs in the selected group.

[0204] At step 1008, the base station may allocate in SU-MIMO mode in a first round, PRBs from the determined set of PRBs to at least one UE in the selected group, such that the number of allocated PRBs to each UE in the selected group is restricted to a number at which the uplink transmit power of the UE is lesser than or equal to its maximum uplink transmit power limit such that PSD limit is not reduced (i.e., not compromised). In other words, the base station 110 may allocate a number of PRBs to be distributed to each UE, such that this number does not exceed the PRB_nMCS value of the UE.

[0205] At step 1010, the base station 110 may allocate in MU-MIMO mode in a second round, remaining PRBs from the determined set of PRBs, to at least two UEs within the selected group, on a determination that each of the at least two UEs is allocated with PRBs that is lesser than the number at which the UE achieves its maximum uplink transmit power limit such that PSD limit is not reduced. In other words, at step 1010, if for two or more UEs, its PRB_nMCS value is greater than Current AllocationJJ E , then those UEs may be allocated with additional PRBs in the second round.

[0206] The methods and flowcharts depicted in FIGS. 3A to 3C, 5, 7, 8, and 10 can comprise further steps not shown and / or may omit certain steps, therefore this should not be construed as limiting the scope of the present disclosure.

[0207] In some example embodiments, the device 900 may comprise means that enable it to perform the steps / operations in FIGS. 3A to 3C, 5, 7, 8, and 10. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry (e.g., the memory 902 and processor 904) or a software module.

[0208] Technical Effect:

[0209] Some of the embodiments disclosed herein utilize PRB allocation methods with spatial domain multiplexing (SDM), which can improve system performance by efficient and fair allocation of PRBs among eligible individual or paired UEs in a manner that higher power per PRB or power spectral density (PSD) can be achieved. As disclosed in some of the embodiments herein, the improved pairing opportunities, among the scheduled UEs, can lead to higher spectral efficiency and enhanced uplink throughput.

[0210] In the drawings and specification, there have been disclosed exemplary embodiments of the invention. Although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. It will be apparent to those having ordinary skill in this art that various modifications and variations may be made to the embodiments disclosed herein, consistent with the present invention, without departing from the spirit and scope of the present invention. Other embodiments consistent with the present invention will become apparent from consideration of the specification and the practice of the description disclosed herein.

Claims

We claim:

1. A method for resource allocation for a plurality of user equipment devices (UEs) in a wireless communication network, the method comprising: selecting a group of UEs (N) within the plurality of UEs; obtaining, for each UE in the selected group, a scheduling metric; determining a set of resource blocks (PRBs) for the selected group of UEs based on the obtained scheduling metric; and allocating, in SU-MIMO mode in a first round, resource blocks from the determined set of resource blocks to at least one UE in the selected group, such that the number of allocated resource blocks to each UE in the selected group is restricted to a number at which the uplink transmit power of the UE is lesser than or equal to its maximum uplink transmit power limit such that PSD limit is not reduced; and in MU-MIMO mode in a second round, remaining resource blocks from the determined set of resource blocks, to at least two UEs (NSDM), within the selected group, on a determination that each of the at least two UEs is allocated with resource blocks that is lesser than the number at which the UE achieves its maximum uplink transmit power limit such that the PSD limit is not reduced.

2. The method as claimed in claim 1, comprising: allocating, in a third round, further remaining resource blocks of from the first and the second round to one or more UEs (N - NSDM) in the selected group of UEs.

3. The method as claimed in claim 2, wherein the allocating of resource blocks in the third round is such that the transport block size of the one or more UEs is maximized.

4. The method as claimed in claim 1, wherein allocating the remaining resource blocks in the second round, comprises: pairing the at least two UEs, within the selected group, to create at least one UE pair, occurs on a determination that the spatial correlation between the at least two UEs is lesser than a correlation threshold.

5. The method as claimed in claim 4, wherein the pairing of the at least two UEs is based on a UE pair index using orthogonality criteria.

6. The method as claimed in claim 4, wherein allocating the remaining resource blocks in the second round comprises: allocating the at least one UE pair with fully overlapping or partially overlapping resource blocks.

7. The method as claimed in claim 6, wherein allocating the at least one UE pair with partially overlapping resource blocks is given by,PRB_budget_UEPairSk= min (max PRB_nMCSi , PRB_budget_UEGSk), whereinPRB_budget_UEPairSkrepresents the number of resource blocks allocated to a specific UE pair among the at least one UE pair, max PRB_nMCSi represents the maximum number of resource blocks of a UE in the specific iesfeUE pair at which the UE achieves its maximum uplink transmit power limit, andPRB_budget_UEGSkrepresents the total number of resource blocks allocated to all the UEs in the specific UE pair.

8. The method as claimed in claim 6, wherein allocating the at least one UE pair with fully overlapping resource blocks is given by,PRB_budget_UEPairSk= min(maxwhereinPRB_budget_UEPairSkrepresents the number of resource blocks allocated to a specific UE pair among the at least one UE pair, max PRB_nMCSi represents the maximum number of resource blocks of a UE in the specific iesfeUE pair at which the UE achieves its maximum uplink transmit power limit,min PRB_nT BSi represents the maximum number of resource blocks of the UE in the specific iesfeUE pair at which the UE achieves its maximum transport block size value, andPRB_budget_UEGSkrepresents the total number of resource blocks allocated to all the UEs in the specific UE pair.

9. The method as claimed in claim 2, wherein the further remaining resource blocks from the first and the second round include the resource blocks remaining after: the allocation of resource blocks in the first and the second round; and a sharing of resource blocks between at least two UE pairs.

10. An apparatus, comprising: at least one memory; at least one processor operatively coupled to the at least one memory, wherein the at least one processor is configured to cause the apparatus to: select a group of user equipment devices (UEs) within a plurality of UEs; obtain, for each UE in the selected group (N), a scheduling metric; determine a set of resource blocks (PRBs) for the selected group of UEs based on the obtained scheduling metric; and allocate, in SU-MIMO mode in a first round, resource blocks from the determined set of resource blocks to at least one UE in the selected group, such that the number of allocated resource blocks to each UE in the selected group is restricted to a number at which the uplink transmit power of the UE is lesser than or equal to its maximum uplink transmit power limit such that PSD limit is not reduced; and in MU-MIMO mode in a second round, remaining resource blocks from the determined set of resource blocks, to at least two UEs (NSDM), within the selected group, on a determination that each of the at least two UEs is allocated with resource blocks that is lesser than the number at which the UE achieves its maximum uplink transmit power limit such that the PSD limit is not reduced.

11. The apparatus as claimed in claim 10, wherein the at least one processor is configured to cause the apparatus to: allocate, in a third round, further remaining resource blocks of from the first and the second round to one or more UEs (N - NSDM) in the selected group of UEs.

12. The apparatus as claimed in claim 11, wherein the allocating of resource blocks in the third round is such that the transport block size of the one or more UEs is maximized.

13. The apparatus as claimed in claim 10, wherein in the allocation of the remaining resource blocks in the second round, the at least one processor is configured to cause the apparatus to: pair the at least two UEs, within the selected group, to create at least one UE pair, on a determination that the spatial correlation between the at least two UEs is lesser than a correlation threshold.

14. The apparatus as claimed in claim 13, wherein the pairing of the at least two UEs is based on a UE pair index using orthogonality criteria.

15. The apparatus as claimed in claim 13, wherein in the allocation of the remaining resource blocks in the second round, the at least one processor is configured to cause the apparatus to: allocate the at least one UE pair with fully overlapping or partially overlapping resource blocks.

16. The apparatus as claimed in claim 15, wherein allocating the at least one UE pair with partially overlapping resource blocks is given by,PRB_budget_UEPairSk= min (max PRB_nMCSi , PRB_budget_UEGSk), whereinPRB_budget_UEPairSkrepresents the number of resource blocks allocated to a specific UE pair among the at least one UE pair, max PRB_nMCSi represents the maximum number of resource blocks of a UE in the specific iesfeUE pair at which the UE achieves its maximum uplink transmit power limit, andPRB_budget_UEG$krepresents the total number of resource blocks allocated to all the UEs in the specific UE pair.

17. The apparatus as claimed in claim 15, wherein allocating the at least one UE pair with fully overlapping resource blocks is given by,PRB_budget_UEPairSk= min(max PRB_nMCSi , minPRBjiTBSi , PRB_budget_UEGSk) whereinPRB_budget_UEPairSkrepresents the number of resource blocks allocated to a specific UE pair among the at least one UE pair, max PRB_nMCSi represents the maximum number of resource blocks of a UE in the specific iesfeUE pair at which the UE achieves its maximum uplink transmit power limit, min PRB_nT BSi represents the maximum number of resource blocks of the UE in the specific iesfeUE pair at which the UE achieves its maximum transport block size value, andPRB_budget_UEGSkrepresents the total number of resource blocks allocated to all the UEs in the specific UE pair.

18. The apparatus as claimed in claim 11, wherein the further remaining resource blocks from the first and the second round include the resource blocks remaining after: the allocation of resource blocks in the first and the second round; and a sharing of resource blocks between at least two UE pairs.

19. A computer program product comprising instructions stored on a computer readable storage medium, wherein at least one processor of an apparatus is configured to execute the instructions to cause the apparatus to perform a process including the method according to any of claims 1-9.

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