CN112005590B

CN112005590B - Grouping of orthogonal subcarriers

Info

Publication number: CN112005590B
Application number: CN201880092019.XA
Authority: CN
Inventors: 幸红年; 江玮; 胡轩
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2023-11-03
Anticipated expiration: 2038-03-30
Also published as: CN112005590A; WO2019183920A1

Abstract

Embodiments of the present disclosure relate to a method, apparatus, and computer-readable storage medium for grouping orthogonal subcarriers. In an example embodiment, subcarriers of a first subset are selected from a first set of subcarriers having a first subcarrier spacing (SCS). The subcarriers of the first subset are orthogonal to the subcarriers of the second set having a second SCS that is a multiple of the first SCS. At least a first subset of subcarriers and a second set of subcarriers are grouped into a first set of subcarriers. With the first group, the network device can optimize subcarrier allocation for the terminal device, thereby improving system performance and efficiency.

Description

Grouping of orthogonal subcarriers

Technical Field

Embodiments of the present disclosure relate generally to the field of communications and, more particularly, relate to a method, apparatus, and computer-readable storage medium for grouping orthogonal subcarriers.

Background

In the third generation partnership project (3 GPP) specifications for fifth generation (5G) New Radios (NR), it is proposed to enable several digital basic configurations (numerologies) in a 5G network, which have different subcarrier spacing (SCS) for different (carrier) frequency bands. For example, larger SCSs of 120kHz and 240kHz are proposed for the millimeter wave (mmW) band, while smaller SCSs of 15kHz, 30kHz, and 60kHz are proposed for the sub-6 GHz band.

It is also proposed to use different digital basic configurations for different services in a 5G network. For example, three typical service classes have been proposed for 5G networks, including enhanced mobile broadband (eMBB) services, large-scale communication services (e.g., large-scale machine type communication (emtc) services), and mission critical communication services (e.g., ultra-reliable low-latency communication (wrlc) services). The eMBB service aims to improve spectral efficiency and peak throughput. The mctc service aims to increase the number of terminal devices served and reduce the device cost. The ul lc service requires reduced end-to-end delay and improved robustness of data transmission.

Short subframes have been proposed to reduce end-to-end delay for the ul lc service, which is a critical service in these three classes of service. For example, a short subframe may generally reduce the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols per subframe to two OFDM symbols per subframe. Delay reduction can also be achieved by using larger SCS. For example, if a larger SCS is used in the frequency domain, a smaller OFDM symbol duration may be implemented in the time domain. The subframe duration may be reduced by increasing the SCS without modifying the number of OFDM symbols per subframe. Thus, it is proposed that a digital basic configuration with a larger SCS can be used for the ul lc service, while a digital basic configuration with a smaller SCS can be used for the eMBB service.

In order to provide different delay requirements for different services, different digital basic configurations may be combined in the same frequency band. However, such a combination can potentially result in digital basic inter-configuration interference (INI) between concurrent different digital basic configurations.

Disclosure of Invention

In general, example embodiments of the present disclosure provide a method, apparatus, and computer-readable storage medium for grouping orthogonal subcarriers.

In a first aspect, a method at a network device is provided. Subcarriers of a first subset are selected from a first set of subcarriers having a first subcarrier spacing (SCS). The subcarriers of the first subset are orthogonal to the subcarriers of the second set having a second SCS that is a multiple of the first SCS. At least a first subset of subcarriers and a second set of subcarriers are grouped into a first set of subcarriers.

In a second aspect, there is provided 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 are configured to, with the at least one processor, cause the apparatus to: selecting a first subset of subcarriers from a first set of subcarriers having a first subcarrier spacing (SCS), the first subset of subcarriers being orthogonal to a second set of subcarriers having a second SCS, the second SCS being a multiple of the first SCS; and grouping at least the first subset of subcarriers and the second set of subcarriers into a first group of subcarriers.

In a third aspect, a computer-readable storage medium having a computer program stored thereon is provided. The computer program, when executed by a processor, causes the processor to perform the method according to the first aspect.

It should be understood that the summary is not intended to identify key or essential features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

Some example embodiments will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows an example INI between two digital base configurations multiplexed by an FDM scheme;

FIGS. 2 (a) and 2 (b) show example simulated Symbol Error Rates (SER) with two digital basic configurations with 15kHz and 30kHz SCSs at different GB's;

FIGS. 3 (a) and 3 (b) show example effects of power imbalance on INI at different GB's;

FIGS. 4 (a) and 4 (b) show an example effect of modulation order on INI;

FIG. 5 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

FIG. 6 illustrates a flowchart of an example method according to some embodiments of the present disclosure;

FIG. 7 illustrates an example selection of a first subset in accordance with some embodiments of the present disclosure;

Fig. 8 illustrates an example segmentation of a first PRB according to some embodiments of the present disclosure;

fig. 9 illustrates an example priority assignment of a first group to terminal devices at certain geographic locations in a cell, according to some embodiments of the present disclosure; and

fig. 10 shows a simplified block diagram of a device suitable for implementing embodiments of the present disclosure.

The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements.

Detailed Description

Principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and practicing the present disclosure without placing any limitation on the scope of the disclosure. The disclosure described herein may be implemented in various ways other than those described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard or protocol, such as Long Term Evolution (LTE), LTE-advanced (LTE-a), and 5G NR, and employs any suitable communication technology, including, for example, multiple Input Multiple Output (MIMO), OFDM, time Division Multiplexing (TDM), frequency Division Multiplexing (FDM), code Division Multiplexing (CDM), bluetooth, zigBee, machine Type Communication (MTC), eMBB, mctc, and ul lc technologies. For discussion purposes, in some embodiments, an LTE network, an LTE-a network, a 5G NR network, or any combination thereof is taken as an example of a communication network.

As used herein, the term "network device" refers to any suitable device on the network side of a communication network. The network devices may include any suitable devices in an access network of a communication network, including, for example, base Stations (BSs), relays, access Points (APs), node BS (nodebs or NB), evolved nodebs (eNodeB or eNB), gigabit nodebs (gNB), remote radio modules (RRU), radio Headers (RH), remote Radio Heads (RRH), low power nodes (such as femto, pico nodes, etc.). For discussion purposes, in some embodiments, an eNB is taken as an example of a network device.

The network devices may also include any suitable devices in the core network, including, for example, multi-standard radio (MSR) radio devices such as MSR BS, network controllers such as Radio Network Controllers (RNC) or Base Station Controllers (BSC), multi-cell/Multicast Coordination Entities (MCEs), mobile Switching Centers (MSC) and MMEs, operation and management (O & M) nodes, operation Support System (OSS) nodes, self-organizing network (SON) nodes, positioning nodes such as enhanced services mobile positioning centers (E-SMLCs), and/or Mobile Data Terminals (MDT).

As used herein, the term "terminal device" refers to a device that is capable of, configured, arranged and/or operable to communicate with a network device or another terminal device in a communication network. The communication may involve the transmission and/or reception of wireless signals using electromagnetic signals, radio waves, infrared signals, and/or other types of signals suitable for conveying information over the air. In some embodiments, the terminal device may be configured to send and/or receive information without direct human interaction. For example, the terminal device may send information to the network device on a predetermined schedule when triggered by an internal or external event, or in response to a request from the network side.

Examples of terminal devices include, but are not limited to, user Equipment (UE) such as smart phones, wireless-enabled tablet computers, laptop-embedded devices (LEEs), laptop-installed devices (LMEs), and/or wireless Customer Premises Equipment (CPE). For purposes of discussion, some embodiments will be described hereinafter with reference to a UE as an example of a terminal device, and the terms "terminal device" and "user equipment" (UE) may be used interchangeably in the context of the present disclosure.

As used herein, the term "cell" refers to the area covered by radio signals transmitted by a network device. Terminal devices within a cell may be served by a network device and access a communication network via the network device.

As used herein, 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 circuits only) and (b) a combination of hardware circuitry and software, such as (as applicable): (i) The combination of analog and/or digital hardware circuit(s) and software/firmware, and (ii) any portion of the hardware processor(s) with software (including digital signal processor (s)), software and memory(s) that work together to cause a device such as a mobile phone or server to perform various functions, and (c) the hardware circuit(s) and/or processor(s) (such as microprocessor(s) or a portion of microprocessor (s)) that require software for operation, but may not be present when software is not required for operation.

This definition of circuit 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 covers an implementation of only a hardware circuit or processor (or multiple processors) or a 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 a server, a cellular network device, or other computing or network device.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "comprising" and variants thereof should be understood as open-ended terms, which mean "including, but not limited to. The term "based on" should be understood as "based at least in part on". The terms "one embodiment" and "an embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". Other definitions (explicit and implicit) may be included below.

As discussed above, several digital basic configurations have been proposed for 5G NR networks, as shown in table 1.

TABLE 1

μ	Δf＝2 ^μ ·15[kHz]	Cyclic prefix
			0	15	Normal state
1	30	Normal state
			2	60	Normal, extended
3	120	Normal state
			4	240	Normal state

These digital basic configurations have five SCS, including 15kHz, 30kHz, 60kHz, 120kHz and 240kHz, and corresponding Cyclic Prefix (CP) configurations. These five SCS can be used in different carrier bands and for different services in the 5G NR network, such as eMBB, emtc service and ul lc service.

Different digital basic configurations may be combined in the same carrier frequency band to achieve different services with different delay requirements. For example, different digital basic configurations may be mixed by means of multiplexing schemes such as FDM, TDM and CDM schemes. However, such a mix of different digital basic configurations may result in INI. In the case where FDM is used as a multiplexing scheme, for example, subcarrier energy leakage outside the subcarrier bandwidth corresponding to one digital basic configuration may interfere with other subcarriers corresponding to other digital basic configurations.

Fig. 1 shows an example INI between two digital basic configurations multiplexed by an FDM scheme. As shown, a digital basic configuration has Δf ₁ While another digital basic configuration has Δf ₂ Is included in the SCS 510 of (c). The Guard Band (GB) 115 between the two digital base configurations is 3.DELTA.f ₁ . In this example, subcarrier energy leakage outside of the subcarrier bandwidths corresponding to the two digital basic configurations interfere with each other.

Some conventional approaches for eliminating INI involve reducing out-of-band (OOB) leakage power, for example, by modifying/adjusting waveforms to improve signal characteristics in the frequency domain. Several multicarrier modulation schemes are provided to generate new/modified OFDM-based multicarrier waveforms that may include Universal Filtered Multicarrier (UFMC), filter Bank Multicarrier (FBMC), generalized Frequency Division Multiplexing (GFDM), and conventional CP-OFDM with weighted overlap and add (WOLA) schemes.

The UFMC scheme aims to filter the subcarrier sets to reduce OOB emissions. Both FBMC-OQAM and GFDM schemes are directed to filtering a single subcarrier to achieve frequency positioning in the subcarrier. CP-OFDM (or CP-OFDM + WOLA) schemes with WOLA focus on time domain signal processing, including, for example, spreading, truncation, inversion, and overlapping. All schemes achieve better OOB leakage suppression compared to the CP-OFDM scheme.

Table 2 shows an example performance comparison of UFMC, FBMC-OQAM, GFDM and CP-OFDM+WOLA schemes to suppress OOB leakage.

TABLE 2

As shown, the FBMC scheme has the best spectral shape, and the other three schemes have similar spectral performance. Since no CP is required for UFMC, FBMC and GFDM schemes, these schemes may suffer from inter-symbol interference (ISI) between OFDM symbols. Furthermore, FBMC and GFDM schemes have high complexity and it is difficult to efficiently integrate MIMO technology. The CP-OFDM + WOLA scheme is much less complex to implement due to the efficient implementation of Fast Fourier Transforms (FFTs). Thus, the CP-ofdm+wola scheme provides a compromise solution that gives acceptable performance from different aspects.

The inventors found that INI can be significantly reduced if the appropriate GB is set between subcarriers with different SCS proposed for 5G NR networks. Fig. 2 (a) and 2 (b) show example simulated Symbol Error Rates (SER) with two digital basic configurations with 15kHz and 30kHz SCS at different GB's. Fig. 2 (a) shows the interference of a 30kHz subcarrier with a 15kHz subcarrier. Fig. 2 (b) shows the interference of a 15kHz subcarrier with a 30kHz subcarrier.

In this example, the Transmit (TX) power for each subcarrier is normalized by a corresponding subcarrier spacing. Thus, a greater bandwidth or more total power (per subcarrier) corresponds to a subcarrier with a 30kHz SCS (or 30kHz subcarrier) than a subcarrier with a 15kHz SCS (or 15kHz subcarrier). Curves 205, 210, 215, 220, 225, 230 and 235 as shown in fig. 2 (a) represent SER with 15kHz subcarriers of gb=0, 15kHz, 30kHz, 45kHz, 60kHz, 75kHz and 90kHz, respectively. Curves 240, 245, 250, 255, 260, 265 and 270 as shown in fig. 2 (b) represent SER with 30kHz subcarriers of gb=0, 15kHz, 30kHz, 45kHz, 60kHz, 75kHz and 90kHz, respectively.

As shown, with normalized power (balanced between the two digital base configurations), the digital base configuration with 30kHz SCS has more interference to the digital base configuration with 15kHz SCS. In addition, as GB increases, INI may decrease. If GB is large enough, the INI may be significantly reduced. However, for a subcarrier with 15kHz SCS, a GB of 45kHz or 75kHz will not bring a SER lower than a GB of 30 kHz. For a subcarrier with 30kHz SCS, SER is acceptable even in case the last subcarrier with 30kHz SCS overlaps with the first subcarrier with 15kHz SCS (gb=0).

The inventors have also found that power imbalance due to, for example, near-far effects may exacerbate power leakage. Fig. 3 (a) and 3 (b) show example effects of power imbalance on INI with different GB, where fig. 3 (a) shows example SER for a 15kHz subcarrier in the presence of interference from a 30kHz subcarrier, and fig. 3 (b) shows SER for a 30kHz subcarrier in the presence of interference from a 15kHz subcarrier.

In this example, no filtering is employed in the frequency domain (and the time domain). Curves 305, 310, 315, 320, 325, 330 and 335 as shown in fig. 3 (a) represent SER for 15kHz subcarriers with gb=0, 15kHz, 30kHz, 45kHz, 60kHz, 75kHz and 90kHz, respectively, with a linear boost in TX power for 15kHz subcarriers. Curves 340, 345, 350, 355, 360, 365 and 370 as shown in fig. 3 (b) represent SER for 30kHz subcarriers with linear boosting of TX power for 30kHz subcarriers with gb=0, 15kHz, 30kHz, 45kHz, 60kHz, 75kHz and 90kHz, respectively.

As shown, as the interference power increases, the power leakage generally becomes more. The required GB is proportional to the power imbalance of the combined system. However, due to spectral inefficiency, very large BGs may be unacceptable.

Furthermore, SER with gb=30 kHz, 60kHz and 90kHz is relatively low for both 15kHz and 30kHz subcarriers, even if the power disturbance is very large. In other words, with the proper GB (integer multiple of 30 kHz), there is no INI between 15kHz and 30kHz subcarriers.

The inventors noted that there may be interference from different User Equipments (UEs) between different uplink channels, such as between a Physical Uplink Control Channel (PUCCH), a Physical Uplink Shared Channel (PUSCH), and demodulation reference symbols (DMRS), due to OFDM symbol duration differences between subcarriers with different SCS. The inventors have also found that modulation order may also affect system performance. Fig. 4 (a) and 4 (b) show an example effect of modulation order on INI, where fig. 4 (a) shows SER for 15kHz subcarrier with M-ray Quadrature Amplitude Modulation (QAM) modulation scheme and fig. 4 (b) shows SER for 30kHz subcarrier with Quadrature Phase Shift Keying (QPSK) modulation scheme. As shown, QPSK modulation is more robust than M-rayQAM modulation because of fewer constellation points.

Embodiments of the present disclosure provide new schemes for mitigating INI. The basic idea is to explore the possible orthogonality between subcarriers to reduce INI in various scenarios, especially where there is a significant power imbalance for some terminal devices.

In various embodiments of the present disclosure, when a network device enables a subcarrier (referred to as a "first set of subcarriers") having SCS (referred to as a "first SCS") and another subcarrier (referred to as a "second set of subcarriers") having a different SCS (referred to as a "second set of subcarriers"), the different SCS being a multiple of the first SCS, the network device selects a subset from the first set that includes subcarriers orthogonal to the second set. The network device then groups at least the first subset of subcarriers and the second set of subcarriers into a set of subcarriers. Through the first group, the network device may optimize subcarrier allocation for the terminal device, thereby improving system performance and efficiency.

For example, the set of subcarriers may be preferentially allocated to the terminal device over the remaining subcarriers of the first set. Since the subcarriers in the group are orthogonal, the preferential allocation to the group can effectively and efficiently reduce INI.

Fig. 5 illustrates an example communication network 500 in which embodiments of the present disclosure may be implemented. The communication network 500 may conform to any suitable protocol or standard that may already exist or will be developed in the future. In some embodiments, the communication network 500 may be an LTE (or LTE-a) network, an NR network, or a combination thereof.

The communication network 500 includes a network device 510. The network device 510 serves two terminal devices (including a first terminal device 520-1 and a second terminal device 520-1, collectively referred to as terminal devices 520) in a cell 530. It should be understood that the number of network devices and terminal devices are shown for illustrative purposes only and are not meant to imply any limitations. Network 500 may include any suitable number of network devices and terminal devices.

The first terminal device 520-1 and the second terminal device 520-2 may communicate with the network device 510 or may communicate with each other via the network device 510. The communication may utilize any suitable technology that is already present or that will be developed in the future.

In network 500, network device 510 may enable any combination of digital basic configurations, e.g., 15kHz, 30kHz, and 60kHz SCS for the sub-6 GHz band and 120kHz and 240kHz SCS for the mmW band as proposed for the 5G NR network. In various embodiments of the present disclosure, network device 510 enables at least two sets of subcarriers, referred to as a first set of subcarriers and a second set of subcarriers with a first SCS and a second SCS. The second SCS is a multiple of the first SCS. By way of example, in embodiments where the communication network 500 is a NR network or a combination of LTE (or LTE-a) and NR networks, the first SCS may be 15kHz and the second SCS may be 30kHz, which is twice as large as the first SCS.

The network device 510 needs to allocate subcarriers to the terminal device 520 for communication. Conventionally, the network device 510 may allocate a first set of subcarriers to the first terminal device 520-1 and a second set of subcarriers to the second terminal device 520-2 by an FDM scheme. Such an allocation may cause an INI between the first terminal device 520-1 and the second terminal device 520-2.

Fig. 6 illustrates a flowchart of an example method 600 according to some embodiments of the present disclosure. The method 600 may be implemented at a network device 510 as shown in fig. 5. For discussion purposes, the method 600 will be described with reference to fig. 5.

At block 605, the network device 510 selects a first subset from the subcarriers of the first set having the first SCS. The subcarriers in the first subset are orthogonal to the subcarriers of the second set having a second SCS that is a multiple of the first SCS.

The multiple may be any suitable integer multiple. For example, in embodiments where the communication network 500 is an NR network or a combination of an LTE (or LTE-a) network and an NR network, the first SCS may be 15kHz and the second SCS may be 30kHz, 60kHz, 120kHz, or 240kHz, which is a multiple of 15 kHz. Alternatively, the first SCS may be 30kHz and the second SCS may be 60kHz, 120kHz or 240kHz.

In some embodiments, the first subset may be selected in consideration of GB between the first set of subcarriers and the second set of subcarriers. Fig. 7 illustrates example selections of a first subset according to some embodiments of the disclosure. As shown, the first SCS 705 between the first set of subcarriers 710-1,..710-N is 15kHz and the second SCS 715 between the second set of subcarriers 720-1,..720-M is 30kHz. N and M are any suitable positive integers.

An FFT may be performed to generate OFDM symbols on the first set of subcarriers and the second set of subcarriers. If a fixed sampling frequency is used for different SCSs, the product FFT of the FFT size with the corresponding SCS _SCS The SCS is identical in the communication network 500. In this example, FFT _30k 2048 is used for the second scs=30 kHz and then the corresponding FFT size for the first scs=15 kHz is FFT _15k =4096. I.e., m=2048 and n=4096.

As shown in fig. 7, in the case where gb=15 kHz is set between the subcarriers of the first set and the subcarriers of the second set, from i _{15k_4096} I of e {1,2,..4096 } _{15k_4096_1} E {2, 4..4096 } is orthogonal to i } _{30k_2048} E {1,2,., 2048}, and is thus selected as a child to be included in the first subset In the carrier wave. If gb=30 kHz, i can be selected _{15k_4096_2} E {1, 3..4095 }. In some embodiments, direct Current (DC) subcarriers in the first set and/or the second set may not be used.

In an embodiment where the first SCS 705 is 15kHz and the second SCS 715 is 60kHz, if FFT _15k =4096 is used for the first SCS 705, FFT _60k =1024 may be used for the second SCS 715. In this case, i can be selected _{15k_4096_3} E {4,8,..4096 } is included in the subcarriers of the first subset.

The set of subcarriers may comprise any suitable set of subcarriers. Based on the current 5G NR specification, the scheduled resource unit is a Physical Resource Block (PRB) consisting of 12 consecutive subcarriers. In some embodiments, the first set and the second set may each include subcarriers in a PRB. The PRBs for the first set are referred to as first PRBs and the PRBs for the second set are referred to as second PRBs.

In some embodiments, the first PRB may be partitioned into at least two Complementary PRBs (CPRBs), referred to as a first CPRB and a second CPRB, respectively. The first CPRB contains subcarriers orthogonal to subcarriers of the second PRB, and the second CPRB contains the remaining subcarriers of the first PRB. The set of at least two CPRBs constitute a complete PRB.

Such segmentation may take into account the GB between the first PRB and the second PRB. Fig. 8 illustrates an example segmentation of a first PRB according to some embodiments of the present disclosure. In this example, the first SCS 705 is 15kHz and the second SCS 715 is 30kHz ("SCS) _max "). The first PRB 805 includes 12 consecutive subcarriers with a first SCS 705=15 kHz, and the second PRB 810 includes 12 consecutive subcarriers with a second SCS 715=30 kHz. Thus, the bandwidth of the first PRB 805 ("PRB) _f,15kHz ") is 15khz×12=180 kHz. Bandwidth of second PRB 810 ("PRB) _f,30kHz ") is 30khz×12=360 kHz.

As shown, if GB 815 between the first PRB 805 and the second 810 is 15kHz, second, fourth, sixth, eighth, tenth, and twelfth subcarriers are selected from the first PRB 805 to form the first CPRB 820, and first, third, fifth, seventh, ninth, and eleventh subcarriers are selected from the first PRB 805 to form the second CPRB 825. The first and second CPRBs are orthogonal in frequency and thus may be used simultaneously. In some embodiments, the CPRB has the same structure as a normal PRB. In this case, only selected subcarriers are activated in each CPRB.

The equivalent GB between the first CPRB 820 and the second PRB 805 is 30kHz, so there is no INI between them. In practice, as long as the equivalent GB is a multiple of the second SCS 715, e.g., n SCS _max There is no INI where n is a non-negative integer. Then, the equivalent GB between the second CPRB 825 and the second PRB 805 is n×SCS _max +15kHz and thus INI is present.

The selection of the first CPRB 820 may vary with GB 815. For example, if GB 815 is 30kHz, the first, third, fifth, seventh, ninth, and eleventh subcarriers in the first PRB 805 are orthogonal to the second PRB 810 and are selected to constitute the first CPRB 820.

Still referring to fig. 6, at block 610, the network device 510 groups at least a first subset of subcarriers and a second set of subcarriers into a set of subcarriers (referred to as a "first set"). For example, as shown in fig. 7, if gb=15 kHz, i _{15k_4096_1} E {2,4,., _{30k_2048} e {1,2,..2048 } may be grouped into a first group. If gb=30 kHz, i _{15k_4096_2} E {1, 3..409 }5 and i _{30k_2048} E {1,2,..2048 } may be grouped into a first group. In an embodiment in which the first set of subcarriers and the second set of subcarriers include subcarriers in the first PRB 805 and the second PRB 810, respectively, the first CPRBs 820 and the second PRB 810 are grouped into a first group as shown in fig. 8.

All the subcarriers in the first group are orthogonal, so there is no INI between these subcarriers. The first group may be reserved for certain scenarios, e.g. scenarios where there is severe INI, ISI-intensive or worse channel conditions due to high power imbalance. In this way, system performance and efficiency may be significantly improved.

However, the remaining subcarriers in the first set are not orthogonal to the subcarriers of the second set in the first set. An INI will be induced if these subcarriers are used together with the subcarriers in the first group. In some embodiments, at block 615, network device 510 may preferentially allocate the first set of subcarriers to terminal device 520. For example, the terminal device 520 in the cell 530 may preferably use the first group as long as there are remaining subcarriers in the first group.

In some embodiments, network device 510 may perform prioritization based on a power imbalance associated with terminal device 520. For example, the network device may determine whether the power imbalance associated with the terminal device 520 is high (e.g., above a threshold). If so, the network device 510 may assign the first set of subcarriers to the terminal device 520 to reduce the severe INI that may be caused by the high power imbalance.

Network device 510 may consider any suitable factors to determine the power imbalance associated with terminal device 520. In some embodiments, the power imbalance may be determined based on a received power ratio associated with terminal device 520. For example, in the case where the network device 510 serves a plurality of terminal devices 510 in the cell 530, the network device 510 may collect the received power of all the served terminal devices 520. The ratio vector is formed based on the received power ratio between the target terminal device and other terminal devices in the same cell. If the variance of the ratio vector is less than a threshold value Thr, given below, the power imbalance associated with the target terminal device may be determined to be low:

Wherein RX is _{UE_target} Representing the received power of the target terminal device, and RX _{UE_i} Representing the received power of the i-th terminal device other than the target terminal device. Otherwise, the power imbalance is considered high and then the subcarriers in the first group may be used.

This scheme based on the variance of the ratio vector can be modified by GB. For example, if there are only a few elementsWith larger values (meaning high power imbalance), these elements can be excluded from the variance calculation. The terminal devices corresponding to these elements may be scheduled to use other subcarriers than the first group, with GB as large as possible.

In some embodiments, the power imbalance may be determined based on the location of the terminal device 520 within the cell 530, as near-far effects generated by movement of the terminal device 520 within the cell may result in power imbalance. In these embodiments, if the distance of the terminal device 510 from the network device 510 is less than a threshold distance (referred to as a first threshold distance) or greater than another threshold distance (referred to as a second threshold distance), it may be determined that the terminal device 510 has a high power imbalance.

Fig. 9 illustrates an example priority assignment of a first group to a terminal device 520 at certain geographic locations in a cell 530, according to some embodiments of the present disclosure. In this example, if the terminal device 520 is located in the center region 905 or the edge region 910 of the cell 530, the terminal device 520 may be scheduled to use the first group due to the potentially high power imbalance. If the terminal device 520 is located in the middle region 915 of the cell 530, the terminal device 520 may use other subcarriers.

The grouping scheme may be extended to scenarios where the network device 510 enables more than two different digital basic configurations. For example, in addition to the first set and the second set, the network device 510 may also enable another set of subcarriers (referred to as a "third set") with another SCS (referred to as a "third set"). The first SCS is a multiple of the third SCS. In this example, network device 510 may select a subset (referred to as a second subset) from the third set of subcarriers that includes subcarriers that are orthogonal to the second set of subcarriers. The network device 510 then groups the first subset of subcarriers and the second set of subcarriers into a first group.

All other subcarriers in the first set and the third set may form another group. In some embodiments, the set may be further partitioned to obtain other orthogonal subcarrier sets. For example, when the first subset is selected from the subcarriers of the first set, the network device may divide the first set into two subsets, including the first subset and another subset (referred to as a third subset). The subcarriers in the third subset are not orthogonal to the subcarriers of the second set. The network device 510 may then select from the third set of subcarriers, a subcarrier that contains another set orthogonal to the third set of subcarriers (referred to as a fourth subset). The subcarriers of the third subset and the subcarriers of the fourth subset may be grouped into another group, referred to as a second group. In this case, the first group may be assigned to the terminal device 520 in preference to the second group. In addition, all subcarriers in the second group are also orthogonal to each other. Thus, the second group may take precedence over the remaining subcarriers in the third set.

By way of example, in an embodiment where the first scs=30 kHz, the second scs=60 kHz and the third scs=15 kHz, all subcarriers with 60kHz SCS, half subcarriers with 30kHz SCS, and quarter subcarriers with 15kHz SCS belong to the first group. The other half of the subcarriers with 30kHz SCS and the remaining two thirds of the subcarriers with 15kHz SCS belong to the second group. The remaining quarter of the subcarriers with 15kHz SCS may form another group.

In addition, in embodiments where the first, second, and third sets all contain subcarriers in PRBs, additional groupings of subcarriers other than the first group may result in additional partitioning of the CPRBs, as described above. It should be understood that all operations and implementations described above for the first group are equally applicable to the second group.

Embodiments of the present disclosure provide a simple and novel solution to eliminate interference between digital basic configurations. Without modification in the time and frequency domains, groupings of subcarriers and/or PRBs are used to provide orthogonality between subcarriers. Furthermore, by prioritizing the orthogonal group(s) over the non-orthogonal group(s), the INI effect is limited. The scheme may be applied to both uplink and downlink.

The subcarrier grouping, the preferential scheduling of orthogonal groups and the CPRB construction involved in the scheme may be applied in a 5G NR network using different digital basic configurations, or in a context where LTE and 5GNR networks coexist. Although this scheme is used to avoid mutual interference in the frequency domain, it may be used in combination with other domains such as time domain, code domain and space domain to provide more effective and efficient orthogonality between terminal devices.

Furthermore, since orthogonal group(s) are sufficient for the network, the scheme may provide acceptable performance in different scenarios, especially in low and medium load situations. This scheme may provide high spectral efficiency because fewer or even no GB is needed for the orthogonal group. With 15kHz and 30kHz SCS enabled by network device 510, up to 3/4 of the resources can be used without GB. In addition, the scheme is simple and easy to implement, and does not require additional signal processing in the time and frequency domains.

In some embodiments, an apparatus (e.g., network device 510) capable of performing method 600 may include means for performing the various steps of method 600. The apparatus may be implemented in any suitable form. For example, the apparatus may be implemented in a circuit or a software module.

In some embodiments, the apparatus comprises: means for selecting a first subset of subcarriers from among a first set of subcarriers having a first subcarrier spacing (SCS), the first subset of subcarriers being orthogonal to a second set of subcarriers having a second SCS, the second SCS being a multiple of the first SCS; and means for grouping at least the first subset of subcarriers and the second set of subcarriers into a first group of subcarriers.

In some embodiments, the means for selecting comprises: means for selecting a first subset of subcarriers from the first set of subcarriers based on a guard band between the first set of subcarriers and the second set of subcarriers.

In some embodiments, the apparatus further comprises: means for determining the guard band as a multiple of the second SCS.

In some embodiments, the first set of subcarriers includes subcarriers of a first Physical Resource Block (PRB) and the second set of subcarriers includes subcarriers of a second PRB. The means for selecting comprises: means for partitioning the first PRB into at least a first Complementary PRB (CPRB) and a second CPRB, the active subcarriers of the first CPRB being orthogonal to the subcarriers of the second PRB and the active subcarriers of the second CPRB being non-orthogonal to the subcarriers of the second PRB; and means for selecting the active subcarriers of the first CPRB as subcarriers of the first subset.

In some embodiments, the apparatus further comprises means for preferentially allocating the first set of subcarriers to the terminal device.

In some embodiments, the means for prioritizing comprises: means for allocating subcarriers of the first set of subcarriers to the terminal device in response to determining that a power imbalance associated with the terminal device is above a threshold.

In some embodiments, the apparatus further comprises: means for determining a distance of the terminal device from the network device; and means for determining that the power imbalance is above a threshold in response to the distance being below a first threshold distance or above a second threshold distance.

In some embodiments, the network device serves the terminal device and at least one further terminal device in the cell. The apparatus further comprises: means for determining a received power ratio between the terminal device and at least one further terminal device; and means for determining whether the power imbalance is below a threshold based on the received power ratio.

In some embodiments, the means for grouping comprises: means for selecting a second subset of subcarriers from a third set of subcarriers having a third SCS, the first SCS being a multiple of the third SCS, and the second subset of subcarriers being orthogonal to the second set of subcarriers; and means for grouping the first subset of subcarriers and the second set of subcarriers into a first set of subcarriers.

In some embodiments, the means for selecting the subcarriers of the first subset comprises: the apparatus includes means for dividing the first set of subcarriers into a first subset of subcarriers and a third subset of subcarriers, the third subset of subcarriers being non-orthogonal to the second set of subcarriers.

In some embodiments, the means for prioritizing comprises: means for selecting a fourth subset of subcarriers from the third set of subcarriers, the fourth subset of subcarriers being orthogonal to the third subset of subcarriers; and means for grouping at least the third subset of subcarriers and the fourth subset of subcarriers into a second set of subcarriers.

In some embodiments, the apparatus further comprises means for prioritizing allocation of the first set of subcarriers to the terminal device over the second set of subcarriers.

In some embodiments, the apparatus further comprises: the method further includes prioritizing allocation of the second set of subcarriers to the terminal device over remaining subcarriers of the third set except for the second subset of subcarriers and the fourth subset of subcarriers.

Fig. 10 is a simplified block diagram of an apparatus 1000 suitable for implementing embodiments of the disclosure. The device 1000 may be implemented at least at a portion of the network device 510 shown in fig. 5 or as at least a portion of the network device 510.

As shown, the device 1000 includes a processor 1010, a memory 1020 coupled to the processor 1010, a communication module 1040 coupled to the processor 1010, and a communication interface (not shown) coupled to the communication module 1040. Memory 1020 stores at least program 1030. The communication module 1040 is for bi-directional communication. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bi-directional communication between enbs, an S1 interface for communication between a Mobility Management Entity (MME)/serving gateway (S-GW) and an eNB, a Un interface for communication between an eNB and a Relay Node (RN) or a Uu interface for communication between an eNB and a UE.

Assuming that program 1030 includes program instructions that, when executed by associated processor 1010, enable device 1000 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to fig. 6-9. Embodiments herein may be implemented by computer software executable by the processor 1010 of the device 1000, or by hardware, or by a combination of software and hardware. The processor 1010 may be configured to implement various embodiments of the present disclosure.

Memory 1010 may be of any type suitable to the local technology network and may be implemented using any suitable data storage technology, such as non-transitory computer readable storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed memory, and removable memory, as non-limiting examples. Although only one memory 1010 is shown in device 1000, there may be several physically distinct memory modules in device 1000. The processor 1010 may be of any type suitable to the local technology network and may include one or more general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The device 1000 may have multiple processors, such as application specific integrated circuit chips, that are temporally subject to a clock that is synchronized with the host processor.

In general, the various embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as those included in program modules, that execute in a device on a target real or virtual processor to perform the method 600 as described above with reference to fig. 6-9. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split as desired among the program modules. Machine-executable instructions for program modules may be executed within local or distributed devices. In distributed devices, program modules may be located in both local and remote memory storage media.

Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable an apparatus, device, or processor to perform the various processes and operations as described above. Examples of the carrier include a signal, a computer-readable medium.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Moreover, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Likewise, while the above discussion contains several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method for communication, comprising:

At the location of the network device(s),

selecting a first subset of subcarriers from a first set of subcarriers having a first subcarrier spacing (SCS), the first subset of subcarriers being orthogonal to a second set of subcarriers having a second SCS, the second SCS being a multiple of the first SCS; and

grouping at least the first subset of subcarriers and the second set of subcarriers into a first group of subcarriers;

wherein the method further comprises: the first set of subcarriers is preferentially allocated to the terminal device.

2. The method of claim 1, wherein the selecting comprises:

selecting subcarriers of the first subset from the subcarriers of the first set based on guard bands between the subcarriers of the first set and the subcarriers of the second set; and

the guard band is determined as a multiple of the second SCS.

3. The method of claim 2, wherein the first set of subcarriers comprises subcarriers of a first Physical Resource Block (PRB), the second set of subcarriers comprises subcarriers of a second PRB, and the selecting comprises:

dividing the first PRB into at least a first Complementary PRB (CPRB) and a second CPRB, an active subcarrier of the first CPRB being orthogonal to the subcarrier of the second PRB and an active subcarrier of the second CPRB being non-orthogonal to the subcarrier of the second PRB; and

The active subcarriers of the first CPRB are selected as subcarriers of the first subset.

4. A method according to claim 3, further comprising:

in response to determining that a power imbalance associated with the terminal device is above a threshold, subcarriers in the first set of subcarriers are allocated to the terminal device.

5. The method of claim 4, further comprising:

determining the distance between the terminal equipment and the network equipment; and

in response to the distance being below a first threshold distance or above a second threshold distance, the power imbalance is determined to be above the threshold.

6. The method of claim 4, wherein the network device serves the terminal device and at least one further terminal device in a cell, and the method further comprises:

determining a received power ratio between the terminal device and the at least one further terminal device; and

determining whether the power imbalance is above the threshold based on the received power ratio.

7. The method of any of claims 1-6, wherein the grouping comprises:

selecting a second subset of subcarriers from a third set of subcarriers having a third SCS, the first SCS being a multiple of the third SCS, and the second subset of subcarriers being orthogonal to the second set of subcarriers; and

The subcarriers of the first subset and the subcarriers of the second set are grouped into the first set of subcarriers.

8. The method of claim 7, wherein selecting subcarriers of the first subset comprises: dividing the first set of subcarriers into the first subset of subcarriers and a third subset of subcarriers, the third subset of subcarriers being non-orthogonal to the second set of subcarriers; and

wherein the method further comprises:

selecting a fourth subset of subcarriers from the third set of subcarriers, the fourth subset of subcarriers being orthogonal to the third subset of subcarriers; and

grouping at least the third subset of subcarriers and the fourth subset of subcarriers into a second set of subcarriers.

9. An apparatus for communication, comprising:

at least one processor; and

at least one memory including computer program code;

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

wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

and giving priority to the allocation of the first group of subcarriers to the terminal equipment.

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:

the guard band is determined as a multiple of the second SCS.

11. The apparatus of claim 10, wherein the first set of subcarriers comprises subcarriers of a first Physical Resource Block (PRB), the second set of subcarriers comprises subcarriers of a second PRB, and the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to:

12. 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:

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

14. The apparatus of claim 13, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to: dividing the first set of subcarriers into the first subset of subcarriers and a third subset of subcarriers, the third subset of subcarriers being non-orthogonal to the second set of subcarriers; and

Wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to: selecting a fourth subset of subcarriers from the third set of subcarriers, the fourth subset of subcarriers being orthogonal to the third subset of subcarriers; and grouping at least the third subset of subcarriers and the fourth subset of subcarriers into a second set of subcarriers.

15. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, causes the processor to perform the method according to any of claims 1 to 8.