CN116614887A

CN116614887A - Power spectral density aware uplink scheduling

Info

Publication number: CN116614887A
Application number: CN202211621171.7A
Authority: CN
Inventors: S·卡尔亚纳森达拉姆; S·萨哈; S·古拉蒂
Original assignee: Nokia Solutions and Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2022-02-15
Filing date: 2022-12-05
Publication date: 2023-08-18

Abstract

According to one aspect, an apparatus for performing the following is provided. The apparatus is configured to: first, one or more of the plurality of available physical resource blocks are allocated to the plurality of terminal devices, wherein the allocation is performed such that the power spectral density of the plurality of terminal devices matches or exceeds a predefined limit of the power spectral density or a plurality of respective predefined limits. In response to the one or more physical resource blocks remaining available after the allocation, the apparatus is configured to further allocate at least one of the one or more physical resource blocks remaining available to at least one of the plurality of terminal devices, wherein the further allocation is performed such that at least a predefined value of the modulation and coding scheme index is sustainable for the at least one of the plurality of terminal devices.

Description

Power spectral density aware uplink scheduling

Technical Field

Various example embodiments relate to wireless communications.

Background

Efficient use of the air interface bandwidth enables operators to utilize the available Radio Frequency (RF) spectrum to serve more users (i.e., more terminal devices). In the uplink direction, the terminal device can only provide a limited transmission power (e.g., about 23dBm or 200 mW). This may limit the maximum number of PRBs that may be allocated to a given user. Furthermore, such a limitation on the maximum transmission power of the terminal device plus a limitation on the maximum number of users that can be scheduled in a given time slot or mini-slot may result in some PRBs not being used in the scheduling, which in turn results in an under-utilization of the available RF spectrum.

Thus, there is a need for a solution that can more efficiently utilize the full bandwidth available.

Disclosure of Invention

According to one aspect, the subject matter of the independent claims is provided. Embodiments are defined in the dependent claims. The scope of protection sought for the various embodiments is as set forth in the independent claims.

Embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims may be construed as examples useful for understanding the various embodiments.

Drawings

In the following, some example embodiments will be described with reference to the accompanying drawings, in which

Fig. 1 illustrates an example of a communication system to which the embodiments may be applied;

FIGS. 2-4 illustrate examples of processes according to embodiments;

5A, 5B, 5C, 5D, and 5E illustrate simulation results of the benefits of the embodiments compared to the reference solution; and

fig. 6 illustrates an exemplary apparatus according to an embodiment.

Detailed Description

Hereinafter, different exemplary embodiments will be described using a radio access architecture based on long term evolution advanced (LTE-a) or new radio (NR, 5G) as an example of an access architecture to which the embodiments can be applied, without limiting the embodiments to such an architecture. To those skilled in the art It will be clear to the person that by suitably adjusting the parameters and the procedure, the embodiments can also be applied to other kinds of communication networks with suitable components. Some examples of other options applicable to the system are Universal Mobile Telecommunications System (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide Interoperability for Microwave Access (WiMAX),Personal Communication Services (PCS),)>Wideband Code Division Multiple Access (WCDMA), systems using Ultra Wideband (UWB) technology, sensor networks, mobile ad hoc networks (MANET), and internet protocol multimedia subsystem (IMS), or any combination thereof.

Fig. 1 depicts an example of a simplified system architecture showing only some elements and functional entities, all of which are logical units, the implementation of which may vary from that shown. The connections shown in fig. 1 are logical connections; the actual physical connections may vary. It will be apparent to those skilled in the art that the system will typically include other functions and structures in addition to those shown in fig. 1.

However, the embodiments are not limited to the system given as an example, but a person skilled in the art may apply the solution to other communication systems with the necessary characteristics.

The example of fig. 1 shows a part of an exemplary radio access network.

Fig. 1 shows user equipment 100 and 102 (also referred to as terminal equipment) configured to be in a wireless connection with an access node (such as an (e/g) NodeB) 104 providing a cell on one or more communication channels in the cell. The physical link from the user equipment to the (e/g) NodeB is referred to as the uplink or reverse link, while the physical link from the (e/g) NodeB to the user equipment is referred to as the downlink or forward link. It should be appreciated that the (e/g) NodeB or its functionality may be implemented by using any node, host, server or access point entity suitable for such use.

A communication system typically comprises more than one (e/g) NodeB, in which case the (e/g) nodebs may also be configured to communicate with each other via a wired or wireless link designed for this purpose. These links may be used for signaling purposes. The (e/g) NodeB is a computing device configured to control the radio resources of the communication system to which it is coupled. A NodeB may also be referred to as a base station, access point, or any other type of interface device including a relay station capable of operating in a wireless environment. The (e/g) NodeB comprises or is coupled to a transceiver. From the transceiver of the (e/g) NodeB, a connection is provided to the antenna unit, which connection establishes a bi-directional radio link to the user equipment. The antenna unit may comprise a plurality of antennas or antenna elements. The (e/g) NodeB is further connected to a core network 110 (CN or next generation core NGC). Depending on the system, the corresponding part on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW, for providing a connection of User Equipment (UE) to an external packet data network), or a Mobility Management Entity (MME), etc.

A user device (also referred to as UE, user Equipment (UE), user terminal or terminal device) illustrates one type of device to which resources on the air interface are allocated and assigned, and thus any feature of the user device described herein may be implemented with a corresponding apparatus, such as a relay node. One example of such a relay node is a layer 3 relay towards a base station (self-backhaul relay).

User equipment generally refers to portable computing devices including wireless mobile communications devices operating with or without a Subscriber Identity Module (SIM), including, but not limited to, the following types of devices: mobile stations (mobile phones), smart phones, personal Digital Assistants (PDAs), handsets, devices using wireless modems (alarm or measurement devices, etc.), portable and/or touch screen computers, tablet computers, gaming machines, notebooks and multimedia devices. It should be understood that the user equipment may also be an almost exclusive uplink only device, an example of which is a camera or video camera that loads images or video clips into the network. The user device may also be a device with the capability to operate in an internet of things (IoT) network, in which scenario the object is provided with the capability to transmit data over the network without requiring person-to-person or person-to-computer interaction. The user equipment (or in some embodiments, the layer 3 relay node) is configured to perform one or more of the user equipment functions. A user equipment may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal, or User Equipment (UE), to mention just a few names or means.

The various techniques described herein may also be applied to a network physical system (CPS) (a system of computing elements that cooperatively control physical entities). CPS can implement and utilize a multitude of interconnected ICT devices (sensors, actuators, processor microcontrollers, etc.) embedded in different locations in a physical object. The mobile network physical systems in which the physical system in question has inherent mobility are sub-categories of network physical systems. Examples of mobile physical systems include mobile robots and electronics transported by humans or animals.

It should be understood that in fig. 1, the user equipment is depicted as comprising 2 antennas for clarity only. The number of receive and/or transmit antennas may naturally vary depending on the current implementation.

In addition, although the apparatus is depicted as a single entity, different units, processors, and/or memory units (not all shown in FIG. 1) may be implemented.

5G supports the use of multiple-input multiple-output (MIMO) antennas, many more base stations or nodes than LTE (so-called small cell concept), including macro sites that cooperate with smaller base stations and employ multiple radio technologies, depending on the service requirements, use cases, and/or available spectrum. 5G mobile communications support various use cases and related applications including video streaming, augmented reality, different data sharing modes, and various forms of machine type applications including vehicle security, different sensors, and real-time control. 5G is expected to have multiple radio interfaces, i.e., below 6GHz, cmWave and mmWave, and is integrable with existing legacy radio access technologies such as LTE. Integration with LTE may be implemented at least at an early stage as a system in which macro coverage is provided by LTE and 5G radio interface access comes from small cells by aggregation to LTE. In other words, plan 5G supports both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability such as below 6 GHz-cmWave, above 6 GHz-mmWave). One of the concepts considered for use in 5G networks is network slicing, where multiple independent and dedicated virtual subnets (network instances) can be created in the same infrastructure to run services with different requirements on latency, reliability, throughput and mobility.

The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. Low latency applications and services in 5G require content to be brought close to the radio, resulting in local bursts and multiple access edge computation (MEC). 5G allows analysis and knowledge generation to take place at the data source. This approach requires the use of resources such as notebook computers, smart phones, tablet computers and sensors that may not be continuously connected to the network. MECs provide a distributed computing environment for applications and service hosting. It also has the ability to store and process content in the vicinity of cellular subscribers to speed up response time. Edge computing encompasses a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer ad hoc networks and processes (also classified as local cloud/fog computing and grid/mesh computing), dew computing, mobile edge computing, cloudelets, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, internet of things (mass connectivity and/or delay critical), critical communications (automated driving of automobiles, traffic safety, real-time analysis, time critical control, healthcare applications).

The communication system is also capable of communicating with other networks, such as a public switched telephone network or the internet 112, or utilizing services provided by them. The communication network may also be capable of supporting the use of cloud services, for example, at least a portion of the core network operations may be performed as cloud services (which is depicted in fig. 1 by the "cloud" 114). The communication system may also comprise a central control entity or the like providing facilities for networks of different operators, e.g. for cooperation in spectrum sharing.

The edge cloud may be introduced into a Radio Access Network (RAN) by utilizing network function virtualization (NVF) and Software Defined Networks (SDN). Using the edge cloud may mean that access node operations are to be performed at least in part in a server, host, or node operatively coupled to a remote radio head or base station comprising the radio section. Node operations may also be distributed among multiple servers, nodes, or hosts. Application of the cloudRAN architecture enables RAN real-time functions to be performed on the RAN side (in the distributed unit DU 104) and non-real-time functions to be performed in a centralized manner (in the centralized unit CU 108).

It should also be appreciated that the allocation of labor between core network operation and base station operation may be different from the allocation of work of LTE, or even absent. Some other technological advances that may be used are big data and all IP, which may change the way the network is built and managed. The 5G (or new radio NR) network is designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC may also be applied to 4G networks.

The 5G may also utilize satellite communications to enhance or supplement coverage for 5G services, such as by providing backhaul. Possible use cases are to provide service continuity for machine-to-machine (M2M) or internet of things (IoT) devices or for on-board passengers, or to ensure service availability for critical communications as well as future rail/maritime/aviation communications. Satellite communications may utilize Geostationary Earth Orbit (GEO) satellite systems, as well as Low Earth Orbit (LEO) satellite systems, particularly giant constellations (systems in which hundreds of (nano) satellites are deployed). Each satellite 106 in the jumbo constellation may cover several satellite-enabled network entities creating a ground cell. A terrestrial cell may be created by a terrestrial relay node 104 or a gNB located in the ground or satellite.

Similar to WLAN or multewire, 5G may also use unlicensed spectrum. The 5G operating in unlicensed spectrum is also referred to as NR-U.

It will be clear to a person skilled in the art that the system depicted is only an example of a part of a radio access system, and in practice the system may comprise a plurality of (e/g) nodebs, a user equipment may access a plurality of radio cells, and the system may also comprise other means, such as physical layer relay nodes or other network elements, etc. At least one (e/g) of the (e/g) nodebs may be a home (e/g) NodeB. Additionally, in a geographical area of the radio communication system, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. The radio cells may be macro cells (or umbrella cells), which are large cells, typically up to tens of kilometers in diameter, or smaller cells, such as micro, femto or pico cells. The (e/g) NodeB of fig. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multi-layer network comprising several cells. Typically, in a multi-layer network, one access node provides one or more cells, and thus a plurality (e/g) of nodebs are required to provide such a network structure.

To meet the need for improved deployment and performance of communication systems, the concept of "plug and play" (e/g) nodebs has been introduced. In general, networks capable of using "plug and play" (e/g) nodebs include home NodeB gateways or HNB-GWs (not shown in fig. 1) in addition to home (e/g) nodebs (H (e/g) nodebs). An HNB gateway (HNB-GW) within a network, typically installed within an operator network, may aggregate traffic from a large number of HNBs back to the core network.

The efficient use of the air interface bandwidth enables operators to utilize the available RF spectrum to serve more users (i.e., more terminal devices) and/or to generate additional throughput. Good scheduling algorithms and efficient PRB allocation schemes can improve spectral efficiency by scheduling users at the appropriate times and better utilizing the available PRBs. In the uplink direction, the terminal device can only provide a limited transmission power (e.g., about 23dBm or 200mW, depending on several factors such as terminal device capability and power reduction). This may limit the maximum number of PRBs that may be allocated to a given user. The number of allocated PRBs for a given terminal device may depend on several different factors, such as the location of the terminal device within the cell, the power control parameters used by the terminal device, the Modulation and Coding Scheme (MCS) allocated for the terminal device. Furthermore, such a limitation on the maximum transmission power of the terminal device plus a limitation on the maximum number of users that can be scheduled in a given time slot or mini-slot may result in some PRBs not being used in the scheduling, which in turn results in an under-utilization of the available RF spectrum. In addition to being able to utilize the full bandwidth, the resource assignment method may also ensure improved bandwidth allocation between scheduled terminal devices, so that better spectral efficiency and throughput may be achieved, or more data may be carried on the same amount of air interface resources.

Some current PRB allocation algorithms attempt to equally allocate PRBs among eligible terminal devices with similar quality of service (QoS) requirements and buffered data. However, due to the uplink transmission power limitations of the terminal devices, a lower number of PRBs than its fair share may be assigned to eligible terminal devices on the uplink in order to be able to maintain MCS index 0 (or other lowest allowed MCS index value). Thus, if in a scheduling opportunity, all eligible terminal devices can be provided with equal shares of N available PRBs, and if one of these eligible terminal devices is a power limited terminal device capable of utilizing only M out of the N available PRBs (< N), the N-M PRBs can potentially be further distributed among other scheduled terminal devices. In fact, assigning many PRBs to power-limited terminal devices at the cost of MCS reduction may even compromise system performance in a number of ways. On the one hand, by assigning terminal devices under poor RF conditions, a larger number of PRBs results in assigning lower MCS and lower bps/Hz for these terminal devices. On the other hand, resources are acquired from terminal devices under good RF conditions that can use higher MCS and better spectral efficiency or bit/s/hz values.

Thus, higher spectral efficiency may be achieved if terminal devices under poor RF conditions are assigned PRBs such that their Power Spectral Density (PSD) is not reduced and additional available PRBs are assigned to terminal devices under better RF conditions. Furthermore, in order to improve the performance of power limited and/or cell edge terminal devices, these terminal devices may be scheduled more frequently in the time domain, at least under load conditions where the terminal device in question has not been scheduled in each time slot. The embodiments discussed in detail below provide an uplink PRB allocation scheme for implementing the above concept(s) and thereby overcoming or at least alleviating the above problems.

Fig. 2 illustrates a process according to an embodiment. The illustrated process may be performed by an access node, such as access node 104 of fig. 1, or a particular portion included in the access node (e.g., a computing device or other means for scheduling). In some embodiments, the illustrated process may be performed by a distributed unit of an access node (e.g., DU 104 of fig. 1) or a centralized unit of an access node. Hereinafter, an entity performing the process is simply referred to as an apparatus without loss of generality.

Initially, it may be assumed that the apparatus knows a plurality of terminal devices for which uplink PRB allocation should be performed. The plurality of terminal devices may correspond to terminal devices selected for a current Transmission Time Interval (TTI) schedule. In some embodiments, the apparatus or another apparatus communicatively connected to the apparatus may have performed time domain scheduling for a plurality of terminal devices.

In block 201, the apparatus allocates one or more of a plurality of available PRBs to a plurality of terminal devices. The allocation in block 201 is performed such that predefined limits (or thresholds) of the power spectral densities of the plurality of terminal devices match (i.e. are equal) or are exceeded (i.e. predefined limits of the power spectral densities are unaffected). In other words, the allocation of a given terminal device is limited to a maximum number of PRBs, which still corresponds to a value of the power spectral density (i.e. power per PRB) calculated for the terminal device, which is equal to or higher than a predefined limit. The allocation of block 201 is hereinafter referred to as a first round PRB allocation.

In some embodiments, in block 201, rather than defining a single predefined limit for all of the plurality of terminal devices, a plurality of predefined limits for power spectral density may be defined for the plurality of terminal devices, respectively. At least some of the plurality of predefined limits may be different from each other. Thus, in summary, the allocation in block 201 is performed such that the power spectral densities of the plurality of terminal devices match or exceed a predefined limit or a plurality of respective predefined limits of the power spectral densities (i.e. such that the predefined limit or the plurality of respective predefined limits of the power spectral densities are not affected).

In some embodiments, the predefined limit or limits (respectively) of the power spectral density may correspond to the power spectral density associated with a previous or current allocation of the plurality of terminal devices. Thus, the allocation in block 201 may be performed such that it does not result in performance degradation in terms of power spectral density of any one of the plurality of terminal devices.

In some embodiments, in block 201, for each (or at least one) of the plurality of terminal devices, the apparatus may calculate a maximum number of PRBs that the terminal device may transmit if the power spectral density is not below a predefined limit of the power spectral density (of the terminal device described above) from one or more transmission parameters of the terminal device. The allocation in block 201 may then be performed based on the above-described maximum number of PRBs transmissible by the plurality of terminal devices. That is, in the allocation in block 201, the apparatus may prioritize a terminal device having a lower maximum number of PRBs transmissible by the terminal device over a terminal device having a higher maximum number of PRBs transmissible by the terminal device.

To enable the allocation in block 201, the apparatus may initially calculate values of power spectral densities (i.e., power per PRB) for the plurality of terminal devices based on the transmission parameters of the plurality of terminal devices. The one or more transmission parameters for a given terminal device may include at least the target received power (assuming full path loss compensation) P of the terminal device at the access node ₀ A fractional power control factor alpha for the terminal device and a current path loss PL of the radio channel between the terminal device and the access node. The fractional power control factor a may have a value between 0 and 1, where a=0 indicates no path loss compensation (i.e. all terminal devices transmit at the same power, typically due to different radio channels)Resulting in different received powers) a = 1 represents a full path loss compensation for achieving the same received power for all terminal devices. Predefined limits for the power spectral density (or transmission power per PRB) may also be included in the one or more transmission parameters described above.

Using the above three parameters P ₀ Alpha and PL, the transmission power per PRB P of the terminal device _RPB (using absolute values instead of dB) can be written as

P _PRB ＝min(P _PowerClass ，p ₀ *PL ^α )， (1)

Wherein P is _PowerClass Is the maximum output power per PRB (i.e. the highest transmission power of the terminal device for the PRBs) of the (predefined) power class of the terminal device. The power level may be specifically a 5G NR power level. Transmission power per PRB P of terminal device _TX Maximum output power per PRB P, which may correspond to the above power spectral density, but of the power class of the terminal device _PowerClass May correspond to a predefined limit (of the terminal device described above) for the power spectral density.

In order to perform the allocation in block 201, the apparatus may further calculate, for each (or at least one) of the plurality of terminal devices, a maximum number of PRBs "nPRB" that the terminal device may transmit if the power spectral density is not below a predefined limit of the power spectral density (of the terminal device) according to the following formula _MCS ”

Wherein P is _UL Is the uplink transmission power of the terminal equipment, P _PRB Is the transmission power of the terminal device per PRB.

In some embodiments, after the first round of PRB allocation in block 201 is completed, the apparatus may store a Transport Block Size (TBS), information about the allocated PRBs, and/or an MCS for a plurality of terminal devices (or at least the terminal devices for which PRBs are allocated) to a terminal device context maintained in a memory of the apparatus.

In block 202, the apparatus determines whether there are any PRBs available for allocation after the first round of allocation in block 201. In response to one or more PRBs still being available in block 202, the apparatus further allocates at least one of the one or more PRBs still being available to at least one of the plurality of terminal devices in block 203. The further allocation in block 203 is performed such that the predefined value (or one of the predefined values) of the MCS index is sustainable for the above-mentioned at least one (or all) of the plurality of terminal devices. In one embodiment, the predefined value for the MCS index is 0. According to a general definition, the value of the MCS index defines an achievable value of the number of spatial streams, a modulation type, and an achievable value of a coding rate. For example, for an MCS index of 0, the number of spatial streams is 1, the modulation type is Binary Phase Shift Keying (BPSK), and the coding rate is 1/2. The allocation in block 203 is hereinafter referred to as a second round allocation.

In response to no PRBs being available in block 202, the PRB allocation procedure ends in block 204.

In some embodiments, the further allocation in block 203 (i.e., the second round of allocation) includes allocating all PRBs of the one or more PRBs that remain available after the initial allocation in block 201.

In some embodiments, in block 203, the apparatus may calculate, for each (or at least one) of the at least one of the plurality of terminal devices, a maximum number of PRBs for maintaining a predefined value of MCS index while maximizing throughput. The maximum number of PRBs for maintaining a predefined value of the MCS index for a given terminal device may be calculated by: the power spectral density (i.e., power per PRB) for the terminal device at a given path loss is first calculated, and then the maximum number of PRBs used to maintain the predefined value of the MCS index (i.e., the maximum number of PRBs of power spectral density required by determining that the power spectral density is still equal to or greater than the predefined value of the MCS index) is calculated based on the power spectral density and the parameter(s) associated with the predefined value of the MCS index. The further allocation in block 203 may then be performed based on the above-described maximum number of PRBs calculated for the plurality of terminal devices to maintain a predefined value of MCS index (e.g., MCS index of 0).

In some embodiments, in a further allocation in block 203, the apparatus may prioritize terminal devices having a high value of the second predefined scheduling metric (e.g., proportional fair scheduling metric) over terminal devices having a low value of the second predefined scheduling metric. As discussed below in connection with block 408 of fig. 4, a second predefined scheduling metric may be defined herein.

In some embodiments, after the second round of PRB allocation in block 203 is completed, the apparatus may store or update a Transport Block Size (TBS), information about the allocated PRBs, and/or an MCS of the plurality of terminal devices (or at least the terminal devices for which PRBs are allocated in block 203) to a terminal device context maintained in a memory of the apparatus.

In response to no PRBs remaining available in block 202, the apparatus may simply terminate the allocation procedure.

In some embodiments, PRB allocation in the first round in block 201 and/or the second round in block 203 may be performed using a round robin scheduling algorithm or a weighted round robin scheduling algorithm. In cyclic scheduling for PRB allocation, PRBs are assigned to each terminal device in equal parts and cyclic order to handle all terminal devices without priority. In weighted round robin scheduling for PRB allocation, PRBs are assigned to each terminal device in weighted (i.e. at least partially unequal) parts and round robin order to handle all terminal devices without priority. In other embodiments, another scheduling algorithm (e.g., a red-word round robin scheduling algorithm, a weighted fair queuing scheduling algorithm, a proportional fair scheduling algorithm, or a delay aware scheduling algorithm) may be employed. The scheduling algorithms used in the first wheel 201 and the second wheel 203 may be the same (or the same type of) algorithm or different (or different types of) algorithms.

By performing uplink PRB allocation in two rounds as defined in connection with blocks 201, 203, any cell-centric terminal device (typically with high quality RF channels) will be allocated more PRBs than the reference algorithm that tries to allocate PRBs equally between terminal devices with similar QoS and data buffers. Furthermore, cell edge terminal devices (typically with low quality RF channels) will be allocated a smaller number of PRBs so that a higher MCS index can be applied for the above cell edge terminal devices. Thus, higher spectral efficiency and thus higher system throughput may be achieved. Furthermore, the cell-edge terminal device may be scheduled more frequently in the time domain, so that a reduction in the number of PRBs in the grant may be compensated for. The uplink PRB allocation scheme according to embodiments will yield very good results, especially for higher uplink system bandwidths, e.g. 5G uplink system bandwidth (e.g. 100 MHz).

One possible use case of an embodiment relates to a system comprising one or more power limited terminal devices and one or more non-power limited terminal devices. In such a system, one or more power limited terminal devices may be limited to fewer PRBs than non-power limited terminal devices (i.e., predefined limits for power spectral density may be defined differently for power limited and non-power limited terminal devices). Furthermore, the one or more power limited terminal devices may be configured to have a higher predefined value of MCS index than the one or more non-power limited terminal devices. This will help to achieve higher spectral efficiency. Furthermore, one or more power limited terminal devices may be scheduled more frequently in the time domain such that they acquire their fair share within a given time period.

Fig. 3 illustrates another process according to an embodiment. The illustrated process may be performed by an access node, such as access node 104 of fig. 1, or a particular portion included in the access node (e.g., a computing device or other means for scheduling). In some embodiments, the illustrated process may be performed by a distributed unit of an access node (e.g., DU 104 of fig. 1) or a centralized unit of an access node. The process of fig. 3 may correspond to a more detailed implementation of the process of fig. 2. Hereinafter, an entity performing a process is simply referred to as an apparatus without loss of generality.

Initially, in block 301, the apparatus determines a plurality of terminal devices for uplink PRB allocation. The determination in block 301 may comprise selecting, from the M eligible terminal devices, the N terminal devices with the N highest values of the first predefined scheduling metric as the plurality of terminal devices for uplink PRB allocation. Here, M and N are integers greater than 1 (or greater than 0), where m≡n, and a high value of the first predefined scheduling metric for a terminal device indicates that the terminal device will be prioritized for scheduling. The first predefined scheduling metric (or likewise the first predefined priority metric) may be, for example, a proportional fair scheduling metric or a QoS metric.

In some embodiments, the first predefined scheduling metric for a given terminal device may be defined as a metric that depends on (or is defined based on) one or more of the following parameters: signal to interference plus noise ratio (SINR) measured at an access node serving the terminal device, qoS requirements of the terminal device, and subscription of the terminal device in the network. In some embodiments, the first predefined scheduling metric may be defined as one of the listed parameters.

The parameter N may be defined as being equal to a maximum number of terminal devices schedulable in the uplink (in a cell served by the access node) while satisfying Physical Downlink Control Channel (PDCCH) limits and/or one or more predefined hardware constraints (e.g., predefined processing limits). The PDCCH limit is a limit limiting the number of terminal devices that can be scheduled per scheduling opportunity. For example, in a 100MHz deployment with a 2 symbol PDCCH configuration, if aggregation level 4 is used, a maximum of 22 terminal devices may be scheduled in a scheduling opportunity. With respect to predefined hardware constraints (or specifically, predefined processing limits), it may be assumed that the access node software is running on a given hardware specification such that M machine instructions (M being a positive integer) can be executed per second. As the number of terminal devices scheduled per TTI increases, so does the number of machine instructions that need to be executed by the access node. Thus, the predefined processing limit also limits the number of terminal devices that can be scheduled per TTI. As an example, in case of the above capacity, 30 terminal devices may be scheduled per TTI. In other words, the number of terminal devices schedulable per scheduling opportunity with a given hardware capacity is 30. It should be noted that the actual capacity of the terminal device may be defined as the minimum of PDCCH and hardware capacity (i.e., the minimum of 22 and 30 in the above example).

Above, it is assumed that the N highest values of the first predefined scheduling metric indicate that the associated N terminal devices are optimal for scheduling. In other embodiments, the first predefined scheduling metric may be defined in the opposite manner, such that a low value indicates a preference for scheduling or a high scheduling priority. In this case, in block 301, N terminal devices having N lowest values of the first predefined scheduling metric may be selected.

In some embodiments, the apparatus may also perform time domain scheduling in or before block 301.

Then, in blocks 302 to 304, the apparatus may perform allocating available PRBs (or at least some of the available PRBs) to a plurality of terminal devices (i.e., N terminal devices) in a similar manner as described with respect to blocks 201 to 203 of fig. 2.

Finally, in response to the end of the allocation in block 303 (no) or block 304, in block 305 the apparatus causes scheduling of uplink transmissions for the plurality of terminal devices using the determined allocation of the plurality of available PRBs. For example, in block 305, the apparatus may at least cause information about the allocated PRBs to be transmitted to the plurality of terminal devices (or to a portion thereof if not allocated for all of the plurality of terminal devices). This information may be transmitted, for example, as Downlink Control Information (DCI).

Fig. 4 illustrates another process according to an embodiment. The illustrated process may be performed by an access node, such as access node 104 of fig. 1, or a particular portion included in the access node (e.g., a computing device or other means for scheduling). In some embodiments, the illustrated process may be performed by a distributed unit of an access node (e.g., DU 104 of fig. 1) or a centralized unit of an access node. The process of fig. 4 may correspond to a more detailed implementation of the process of fig. 2 and/or 3. Fig. 4 corresponds to an example of cyclic scheduling performed in consecutive first and second round PRB allocation. Hereinafter, an entity performing the process is simply referred to as an apparatus without loss of generality.

Referring to fig. 4, initially, in block 401, the apparatus determines (or selects) a plurality of terminal devices for uplink PRB allocation. Block 401 may correspond entirely to block 301 of fig. 3. The plurality of terminal devices may correspond to terminal devices selected for a current Transmission Time Interval (TTI) schedule.

Then, in block 402, for each (or at least one) of the plurality of terminal devices, the apparatus calculates, from one or more transmission parameters of the terminal device, a predefined limit (i.e. the power limit P per PRB) at which the power spectral density (of the terminal device described above) is not impaired _PowerClass ) Physical resource blocks "nPRB" that can be transmitted by a terminal device _MCS "maximum number. The one or more transmission parameters for a given terminal device may include at least the target received power (assuming full path loss compensation) P of the terminal device at the access node ₀ A fractional power control factor alpha of the terminal device and a current path loss PL of the radio channel between the terminal device and the access node (and optionally also a maximum output power P of the power class of the terminal device) _PowerClass ). The calculation may be performed using (1) and (2), for example.

Further, in block 402, for each (or at least one) of the above-mentioned at least one of the plurality of terminal devices, the apparatus calculates a maximum number of physical resource blocks "nPRB" for maintaining a predefined value (e.g., 0) of MCS index while maximizing throughput _TBS ”。

As described above, allocation of PRBs may be performed in two consecutive rounds of allocation. In fig. 4, the first round of PRB allocation involves blocks 403 to 406, 414, while the second round of PRB allocation involves blocks 407 to 412, 415.

In a first round of PRB allocation, the apparatus initially selects an and "nPRB" of a plurality of terminal devices in block 403 _MCS The "lowest value (calculated in" nPRB for a plurality of terminal devices) _MCS "in a plurality of values of" in the list of the terminal devices). For example, in block 403,the apparatus may be based on "nPRB _MCS The values of "order the plurality of terminal devices in ascending order, and a first (i.e., initial) terminal device in the above-described ordered set comprising the plurality of terminal devices is selected. Obviously, a plurality of terminal devices can be based on "nPRB _MCS The values of "are equally ordered in descending order and the last terminal device in the ordered set described above may be selected first. In other embodiments, the terminal devices may be ordered in another order (based on other metrics).

In block 404, the apparatus calculates an initial maximum number of PRBs to be allocated to the (selected) terminal device "Round1UEShare" as follows "

Where "remainingPRBs" is the number of current remaining PRBs to be allocated, w _UE，i Is per "nPRB _MCS "the weight or weighting factor of the i-th terminal device (i.e., the selected terminal device) among the plurality of terminal devices arranged in the ascending order described above, j is the summation index, and N is the number of the plurality of terminal devices. For the initial terminal device, the index i has a value of 1.w (w) _UE，i The index i in (a) corresponds to the above-mentioned ordering order of the plurality of terminal devices in the first round of PRB allocation, i.e. the i-th terminal device corresponds to having "nPRB _MCS "the i-th lowest value terminal device. Weighting factor w for a given terminal device _UE，i May depend on, for example, qoS metrics and one or more radio channel metrics. "RemainingPRBs1" is specifically associated with the first round of PRB allocation. At this point in the process (i.e., when an allocation is performed for the first terminal device), the "remaining PRBs" correspond to all available PRBs for uplink allocation.

In (3), a general case is considered in which a plurality of terminal devices are assigned with a corresponding plurality of weighting factors. In some embodiments, these weighting factors may be defined as one weighting factor for all of the plurality of terminal devices. In such an embodiment, equation (3) may be written in simplified form as

Where "remainings ues1" is the number of currently remaining terminal devices (here also including the selected terminal device) among the plurality of terminal devices waiting for (first round) allocation. At this point in the process (i.e., when an allocation is performed for the first terminal device), the "remaining ues1" corresponds to all of the plurality of terminal devices determined for uplink PRB allocation in block 401.

In block 405, the apparatus allocates an initial number of PRBs to the terminal device, the initial number being equal to

AllocatedPRBs1＝min(Round1UEShare1，nPRB _MCS )， (5)

Wherein "nPRB _MCS "is the maximum number of PRBs that can be transmitted by a terminal device (without affecting the power per PRB). (5) The "Round1UEShare" in (2) is provided by (3) or (4).

In block 406, the apparatus determines whether all PRBs that were originally available for allocation have been allocated.

If it is determined in block 406 that all PRBs have been allocated, in block 413 the apparatus schedules uplink transmissions for a plurality of terminal devices using the allocation of the plurality of available PRBs determined in blocks 401 to 406, 414. The causing scheduling in block 413 may be performed similar to that described in connection with block 305 of fig. 3.

If it is determined in block 406 that not all PRBs have been allocated, then in block 407 the apparatus determines whether all of the plurality of terminal devices have undergone a first round of allocation (i.e., whether at least one PRB has been allocated for each of the plurality of terminal devices). If this is not the case, the apparatus selects the terminal device of the plurality of terminal devices having the next lowest "nPRB in block 414 _MCS The "next terminal device (i.e., the lowest" nPRB among the one or more terminal devices for which the first round of PRB allocation has not been performed yet) _MCS "). Using the notation of (3), in block 414, the apparatus increments index i by 1. Then, the above bonding is repeated for the next terminal device Blocks 405 through 406 describe the process.

This procedure for the first round of PRB allocation is in terms of "nPRB _MCS The "ascending order of values is repeated until it is determined in block 406 that all available PRBs have been allocated, or it is determined in block 407 that one or more PRBs have been allocated to each of the plurality of terminal devices. The values of the parameters "RemainingPRBs" and "remaininues 1" are updated periodically during the above procedure (e.g., in block 414) when PRBs are allocated to the terminal device. The update may be performed, for example, according to the following equation:

RemainingPRBs＝RemainingPRBs-AllocatedPRBs

(6)

RemainingUEs1＝RemainingUEs1-1。

(7)

as described in connection with fig. 2, after the first round of PRB allocation is completed, the apparatus may store a Transport Block Size (TBS), information about the allocated PRBs, and/or an MCS of the plurality of terminal devices (or at least the terminal devices for which the PRBs are allocated) to a terminal device context maintained in a memory of the apparatus.

If it is determined in block 407 that all of the plurality of terminal devices have undergone the first round of PRB allocation, the apparatus proceeds to the second round of PRB allocation. In a second round of PRB allocation, the apparatus initially selects a terminal device of the plurality of terminal devices corresponding to a highest value of the predefined second scheduling metric in block 408. Here, it is assumed that a high value of the predefined second scheduling metric indicates that the associated terminal device should be prioritized in scheduling. The second predefined scheduling metric may be, for example, a proportional fair scheduling metric or a QoS metric. The second predefined scheduling metric may be the same as or different from the first predefined scheduling metric.

In some embodiments, the second predefined scheduling metric for a given terminal device may be defined as a metric that depends on (or is based on) one or more of the following parameters: signal to interference plus noise ratio (SINR) measured at an access node serving the terminal device, qoS requirements of the terminal device, and subscription of the terminal device in the network. In some embodiments, the second predefined scheduling metric may be defined as one of the listed parameters.

The selecting in block 408 may involve determining or calculating a value of a predefined second scheduling metric for the plurality of terminal devices, ordering the plurality of terminal devices in a descending (or ascending) order based on the value of the predefined second scheduling metric, and selecting the initial terminal device of round2 allocation as a first (or last) terminal device comprising the ordered set of the plurality of terminal devices.

In block 409, the apparatus calculates a second maximum number of PRBs to be allocated to the terminal device having the lowest value of the second predefined scheduling metric, "Round2UEShare"

Where "remainingPRBs" is the number of current remaining PRBs to be allocated, w' _UE，i Is the weight or weighting factor of the i-th terminal device of the plurality of terminal devices (i.e. the selected terminal device) arranged in the above-mentioned descending order value of the second predefined scheduling metric, j is the summation index and N is the number of the plurality of terminal devices. For the initial terminal device, the index i has a value of 1.w' _UE，i The index i of (a) corresponds to the above-mentioned ordering order of the plurality of terminal devices in the second round of PRB allocation, i.e. the i-th terminal device corresponds to the i-th highest value terminal device having the second predefined scheduling metric. Weighting factor w 'for a given terminal device' _UE，i May depend on, for example, qoS metrics and one or more radio channel metrics. "RemainingPRBs1" is specifically associated with the first round of PRB allocation. Weighting factor w 'used in second round PRB allocation' _UE，i The weight factor "w" that can be used in the first round of PRB allocation as a whole _UE，i "corresponding, although their order may be different (here based on a second predefined metric instead of" nPRB _MCS "sort". In other words, each terminal device may be associated with the same weighting factor during both the first and second rounds, but with different i indices. Among othersIn an embodiment, different weighting factor values may be used in the first and second rounds.

In (8), a general case is considered in which a plurality of terminal devices are assigned to correspond to a plurality of weighting factors. In some embodiments, these weighting factors may be defined as one weighting factor for all of the plurality of terminal devices. In such an embodiment, equation (8) may be written in simplified form

Where "remaining ues2" is the number of current remaining terminal devices of the plurality of terminal devices waiting for further allocation (i.e., PRB allocation in the second round). Initially, the value of "remaining ues2" is equal to the number of the plurality of terminal devices.

In block 410, the apparatus allocates a number of "allocedprbs 2" of additional PRBs to the terminal device with the lowest value of the second predefined scheduling metric, the number being equal to

AllocatedPRBs2＝min(Round2UEShare，nPRB _TBS -nPRB _MCS )，

(10)

Wherein "nPRB _TBS "is the maximum number of physical resource blocks for maintaining a predefined value of the MCS index calculated in block 402 (e.g., MCS index of 0), and" nPRB _MCS "is the maximum number of physical resources that can be transmitted by the terminal device (as described above). Here, "Round2UEShare" may be calculated according to (8) or (9).

In block 411, the apparatus determines whether all PRBs that were originally available for allocation have been allocated (in either the first round of allocation or the second round of allocation). In other words, in block 411, the apparatus determines whether there are more available PRBs to be allocated.

If it is determined in block 411 that all PRBs have been allocated, in block 413 the apparatus schedules uplink transmissions for a plurality of terminal devices using the allocation of the plurality of available PRBs determined in blocks 401 to 406, 414, 415. The causing scheduling in block 413 may be performed similar to that described in connection with block 305 of fig. 3.

In response to the number of currently remaining PRBs (i.e., available PRBs waiting for allocation) being greater than zero after allocation of the "allocatedprabs 2" PRBs in block 411, the apparatus selects the next highest value terminal device with the second predefined scheduling metric in block 415. Subsequently, the procedure described in connection with blocks 409 to 411 and possibly block 412 is repeated for the next terminal device. This process of the second round of PRB allocation is repeated until it is determined in block 411 that all available PRBs have been allocated or it is determined in block 412 that one or more PRBs have been allocated to each of the plurality of terminal devices in the second round of PRB allocation. Similar to the description for the first round, when PRBs are allocated to a terminal device, the values of the parameters "remaininprbs" and "remaininues 2" are updated periodically during the execution of the second round of PRB allocation (e.g., in block 415). The update may be performed, for example, according to the following equation:

RemainingPRBs＝RemainingPRBs-AllocatedPRBs

(11)

RemainingUEs2＝RemainingUEs2-1。

(12)

as described in connection with fig. 2, after the second round of RPB allocation is completed, the apparatus may store a Transport Block Size (TBS), information about the allocated PRBs, and/or an MCS of the plurality of terminal devices (or at least the terminal devices for which the PRBs are allocated) to a terminal device context maintained in a memory of the apparatus.

If it is determined in block 412 that all of the plurality of terminal devices have undergone a second round of PRB allocation (i.e., no next terminal device is optional in block 415), then in block 413 the apparatus schedules uplink transmissions for the plurality of terminal devices using the allocation of the plurality of available PRBs determined in blocks 401 to 412, 414, 415. The causing scheduling in block 413 may be performed similar to that described in connection with block 305 of fig. 3.

In the embodiments discussed above, it is assumed that all of the plurality of terminal devices for which uplink PRBs are performed have full buffer traffic. In other words, the buffer of the data stream of the terminal device is always assumed to have an unlimited amount of data to be transmitted, and therefore, the transmission of the data payload is never actually ended. However, with the solution according to an embodiment, the case of limited buffer traffic can be handled easily by limiting the (total) PRB allocation (i.e. the total number of allocated PRBs) of a given terminal device to be less than or equal to the number of PRBs that will fully exhaust the buffer of that terminal device. According to an embodiment, the limitation may be performed by the apparatus also performing the rest of the PRB allocation procedure.

The blocks, related functions and information exchange described above by fig. 2-4 are not in absolute time order, some of which may be performed simultaneously or in a different order than the given order.

The PRB allocation solution according to the embodiments has been simulated and its performance compared to the reference algorithm to highlight the advantages of the embodiments. The simulation algorithm according to one embodiment corresponds specifically to the process of fig. 4. In this particular example, the predefined value of the MCS index to be maintained in at least the second round of PRB allocation is zero. The reference algorithm is a frequency domain scheduling algorithm that attempts to equally allocate PRBs among users (i.e., terminal devices) with similar QoS and data buffers. Thus, depending on the availability of PRBs, a user (i.e., terminal device) may be assigned PRBs exceeding the PSD limit using a reference algorithm until its TBS limit (so that MCS 0 may be maintained). The simulation parameters used are given in the table below.

Simulation results of the proposed algorithm and the reference algorithm according to one embodiment are provided/illustrated in the two tables provided below and in fig. 5A, 5B, 5C, 5D and 5E.

The two tables provided below show the results of a comparison of simulations using the reference algorithm and the proposed algorithm according to one embodiment. As can be seen from the table above, in most scenarios the proposed algorithm according to the embodiments is superior to the reference algorithm. The proposed algorithm observes a gain of 6% to 10% for the user throughput geometric mean (Tput) and 8% to 16% for the average UE throughput compared to the reference algorithm.

Fig. 5A and 5B plot simulated user throughput CDF and simulated user throughput versus simulated path loss for the proposed algorithm and the reference algorithm, respectively. It can be observed that with the proposed algorithm most users can achieve better uplink throughput, especially higher throughput or cell-centric users, compared to the resource allocation method of the reference algorithm.

With the proposed algorithm according to one embodiment, good RF users are allocated a significantly larger number of PRBs when compared to the reference algorithm. This contributes to the performance of good RF users (i.e. users or terminal devices that are experiencing good RF conditions), which together with a large number of PRBs can also use a higher MCS, leading to better throughput for these users. This behavior can also be observed from fig. 5C, which shows a simulated Cumulative Distribution Function (CDF) of the proposed algorithm and the reference algorithm. In contrast, reference resource allocation algorithms attempt to allocate PRBs equally among all users, resulting in lower MCS values being allocated to users under less good RF conditions, which results in lower spectral efficiency for these users.

Furthermore, it can be observed from fig. 5C and 5D, which show the simulated CDF and path loss of the allocated PRBs of users, respectively, versus the allocated PRBs, that the PRB allocation for these users is not significantly changed using the proposed algorithm due to the limited power available for uplink transmission by cell edge users.

From fig. 5E, which shows the relation between the number of simulations of scheduling users in the time domain and the path loss for the proposed algorithm and the reference algorithm according to one embodiment, it can be observed that the proposed algorithm allows to schedule the middle cell users more frequently in time and users not in good RF conditions, while users in very good RF conditions are scheduled with lower frequency. More frequent scheduling of less good RF users contributes to improved performance, since these users can only use a limited number of PRBs for scheduling due to the transmission power limitation of the uplink. The increased scheduling frequency in the time domain helps to maintain fairness and thus improve user throughput. The higher scheduling frequency of these users also increases the gain with increasing maximum number of scheduled UEs, which can be observed from the two tables showing simulation results. There are 40 users per cell, although a maximum of 5, 10 or 15 users per cell may be scheduled in one time slot.

Fig. 6 illustrates an example apparatus 601, the apparatus 601 configured to perform at least some of the functions described above in connection with fig. 2-4. The apparatus 601 may be an electronic device comprising electronic circuitry. The apparatus 601 may be an access node (such as the access node 104 of fig. 1) or a portion thereof, a distributed unit of an access node (e.g., the distributed unit 104 of fig. 1) or a portion thereof, or a central unit of an access node or a portion thereof.

The apparatus 601 may comprise communication control circuitry 620, such as at least one processor, and at least one memory 630, the memory 630 comprising computer program code (software) 631, wherein the at least one memory 630 and the computer program code (software) 631 are configured to, with the at least one processor, cause the apparatus to perform any of the embodiments of the apparatus described above. The at least one memory 630 may also include at least one database 632.

The memory 630 may be implemented using any suitable data storage technology such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and devices, fixed memory and removable memory. The memory may include a learning index as described in the previous embodiments.

The apparatus 601 may also include one or more communication interfaces (Tx/Rx) 610, the Tx/Rx610 including hardware and/or software for implementing a communication connection according to one or more communication protocols. For example, one or more communication interfaces 610 may provide apparatus 601 with communication capabilities to communicate in a cellular communication system and enable communication with network nodes and terminal devices. The one or more communication interfaces 610 may include standard well-known components such as amplifiers, filters, frequency converters, (de) modulators, encoder/decoder circuitry, and one or more antennas.

Referring to fig. 6, communication control circuitry 620 may include at least uplink PRB allocation circuitry 621 configured to perform uplink PRB allocation (i.e., at least frequency domain scheduling). The uplink PRB allocation circuitry 621 may be configured to perform at least some of the processes shown in fig. 2-4.

In the present application, the term "circuitry" may refer to one or more or all of the following: (a) A pure hardware circuit implementation (such as an implementation in analog and/or digital circuitry only), and (b) a combination of hardware circuitry and software (and/or firmware), such as (as applicable): (i) Analog and/or digital hardware circuit(s) having software/firmware, and (ii) hardware processor(s) (including digital signal processor (s)) having software, any portion of software and memory that work together to cause an apparatus (such as an end device or access node) to perform various functions, and (c) hardware circuit(s) and/or processor(s) that require software (e.g., firmware) to be able to run, such as microprocessor(s) or a portion of microprocessor(s), but that software may not be present when operation is not required. The definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this disclosure, the term circuitry also encompasses hardware-only circuitry or processor (or processors) or a portion of hardware circuitry or processor and its (or their) accompanying software and/or firmware implementations. For example, if applicable to the particular claim element, the term "circuitry" also encompasses baseband integrated circuits for an access node or terminal device or other computing or network device.

In one embodiment, at least some of the processes described in connection with fig. 2-4 may be performed by an apparatus comprising respective modules for performing at least some of the described processes. Some example components for performing a process may include at least one of: detectors, processors (including dual and multi-core processors), microprocessors, digital Signal Processors (DSPs), controllers, microcontrollers, receivers, transmitters, encoders, decoders, memory, RAM, ROM, software, firmware, displays, user interfaces, display circuitry, user interface software, display software, circuits, antennas, antenna circuitry, application Specific Integrated Circuits (ASICs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), and Field Programmable Gate Arrays (FPGAs). For firmware or software, implementations in accordance with embodiments may be performed by modules (procedures, functions, and so on) of at least one chipset that perform the functions described herein. The software codes may be stored in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor. In the latter case, the memory unit may be communicatively coupled to the processor via various means as is known in the art. In an embodiment, the at least one processor, the memory and the computer program code form processing means, or comprise one or more computer program code portions for performing one or more operations according to any of the embodiments of fig. 2-4, or operations thereof.

The embodiments described above may also be implemented in the form of a computer process defined by a computer program or a part thereof. The embodiments of the method described in connection with fig. 2-4 may be performed by executing at least a portion of a computer program comprising corresponding instructions. The computer program may be provided as a computer readable medium comprising program instructions stored thereon or as a non-transitory computer readable medium comprising program instructions stored thereon. A computer program may be in source code form, object code form, or in some intermediate form and may be stored in some carrier, which may be any entity or device capable of carrying the program. For example, a computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a recording medium, a computer memory, a read-only memory, an electrical carrier signal, a telecommunication signal, and a software distribution package. For example, the computer program medium may be a non-transitory medium. The encoding of the software for executing the illustrated and described embodiments is well within the purview of one of ordinary skill in the art.

Although the embodiments have been described above with reference to examples according to the accompanying drawings, it is obvious that the embodiments are not limited thereto but may be modified in various ways within the scope of the appended claims. Thus, all words and expressions should be interpreted broadly and they are intended to illustrate, not to limit, the embodiments. It is clear to a person skilled in the art that as technology advances, the inventive concept can be implemented in various ways. Furthermore, it is clear to a person skilled in the art that the described embodiments may, but need not, be combined with other embodiments in various ways.

Claims

1. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform:

allocating one or more of a plurality of available physical resource blocks to a plurality of terminal devices, wherein the allocation is performed such that a power spectral density for the plurality of terminal devices matches or exceeds a predefined limit or a plurality of respective predefined limits for the power spectral density; and

In response to one or more physical resource blocks remaining available after the allocation, further allocating at least one of the one or more physical resource blocks remaining available to at least one of the plurality of terminal devices, wherein the further allocation is performed such that a predefined value for a modulation and coding scheme index is sustainable for the at least one of the plurality of terminal devices.

2. The device of claim 1, wherein the predefined value for the modulation coding scheme index is 0.

3. The apparatus according to claim 1 or 2, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the allocation and/or the further allocation using a round robin scheduling algorithm, or a weighted round robin scheduling algorithm.

4. The apparatus of any preceding claim, wherein the further assigning comprises: allocating as many of said one or more physical resource blocks as possible that are still available while maintaining said predefined value of said modulation and coding scheme index for said at least one of said plurality of terminal devices.

5. The apparatus of any preceding claim, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform:

causing uplink transmissions of the plurality of terminal devices to be scheduled using the allocation of the plurality of available physical resource blocks.

6. The apparatus of any preceding claim, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform:

n terminal devices having N highest values of a first predefined scheduling metric are selected from a plurality of eligible terminal devices as the plurality of terminal devices for uplink physical resource block allocation, where N is an integer greater than 1.

7. The apparatus of claim 6, wherein the first predefined scheduling metric is a metric that depends on one or more of the following parameters:

signal-to-interference-and-noise ratio measured at an access node serving a terminal device, quality of service requirements of the terminal device, and

subscription of the terminal device in the network.

8. The apparatus according to any of claims 5 to 6, wherein N is equal to a maximum number of terminal devices schedulable in the uplink while satisfying physical downlink control channel limits and/or one or more predefined hardware constraints.

9. The apparatus of any preceding claim, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform:

calculating, for at least one of the plurality of terminal devices, a maximum number of physical resource blocks transmissible by the terminal device if the power spectral density is not below an associated predefined limit of the power spectral density in accordance with one or more transmission parameters of the terminal device, wherein the allocation is performed based on at least one maximum number of the above-mentioned physical resource blocks calculated for the at least one of the plurality of terminal devices; and

for at least one of the plurality of terminal devices, calculating a maximum number of physical resource blocks for maintaining the predefined value of the modulation and coding scheme index while maximizing throughput, wherein the further allocation is performed based on at least one maximum number of the physical resource blocks for maintaining the predefined value of the modulation and coding scheme index calculated for the at least one of the plurality of terminal devices.

10. The apparatus of claim 9, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform:

in the above allocation, a terminal device having a lower maximum number of physical resource blocks transmittable by the terminal device is prioritized over a terminal device having a higher maximum number of physical resource blocks transmittable by the terminal device; and/or

In the above further allocation, terminal devices having a high value of the second predefined scheduling metric are prioritized over terminal devices having a low value of the second predefined scheduling metric.

11. The apparatus of claim 9 or 10, wherein the one or more transmission parameters include at least: the target received power at the access node, the fractional power control factor, and the current path loss assuming full path loss compensation.

12. The apparatus according to any of claims 9 to 11, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the assigning by:

for at least one of the plurality of terminal devices, per a maximum number nPRB of physical resource blocks transmittable by the terminal device _MCS The following operations are performed in ascending order:

-calculating an initial maximum number of physical resource blocks to be allocated to the terminal device "Round1ue share" as follows "

Where "remaining prbs" is the number of current remaining physical resource blocks to be allocated, w _UE，i Is according to the' nPRB _MCS "weight factor of an i-th terminal device of the plurality of terminal devices arranged in ascending order, and N is the number of the plurality of terminal devices; and

-allocating an initial number of physical resource blocks to the terminal device, the initial number being equal to

AllocatedPRBs1＝min(Round1UEShare1，nPRB _MCS ) Wherein "nPRB _MCS "is the maximum number of physical resource blocks that can be transmitted by the terminal device if the power spectral density is not below the associated predefined limit for the power spectral density.

13. The apparatus according to any of claims 9 to 12, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the further assigning by:

for at least one of the plurality of terminal devices, performing the following in descending order of the value of the second predefined scheduling metric calculated for the terminal device: the second maximum number of physical resource blocks to be allocated to the terminal device, "Round2U EShare", is calculated as follows:

Where "RemainingPRBs" is the number of current remaining physical resource blocks to be allocated, w' UE, i is a weighting factor of the i-th terminal device of the plurality of terminal devices arranged in descending order of the value of the second predefined scheduling metric, and N is the number of the plurality of terminal devices;

allocating a number of additional physical resource blocks to the terminal device, the number being equal to

AllocatedPRBs2＝min(Round2UEShare2，nPRB _TBS -nPRB _MCS ) Wherein "nPRB _TBS "is the maximum number of physical resource blocks for maintaining the predefined value for the modulation coding scheme index while maximizing throughput, and" nPRB _MCS "is the maximum number of physical resources that can be transmitted by the terminal device if the power spectral density is not below the associated predefined limit for the power spectral density.

14. The apparatus of claim 13, wherein the second predefined scheduling metric is a metric that depends on one or more of the following parameters:

subscription of the terminal device in the network.

15. The apparatus of any preceding claim, wherein the apparatus is an access node or part thereof.

16. A method, comprising:

in response to one or more physical resource blocks remaining available after the allocation, at least one of the one or more physical resource blocks remaining available is further allocated to at least one of the plurality of terminal devices, wherein the further allocation is performed such that at least a predefined value for a modulation and coding scheme index is sustainable for the at least one of the plurality of terminal devices.

17. A computer program comprising instructions for causing an apparatus to perform at least the following: