Forming and using non-uniform reference signals with FDSS-based waveforms

Abstract

The node determines a non-uniform reference signal configuration within the allocated frequency band or within a different frequency band segment of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectral shaping. A node transmits or receives reference signals using a non-uniform reference signal configuration.

Description

Technical Field

[0001] The exemplary embodiments herein relate generally to wireless communications, and more particularly, to reference signal transmission and reception in wireless systems. Background Art

[0002] In wireless communication systems, reference signals (RS) are used for various reasons. In cellular systems, these reference signals are sent in specific resource elements, which are elements in the time-frequency space used for transmission or reception. The pattern of resource elements in the time-frequency space is usually fixed in advance, so both the transmitter and receiver know where the RS will be.

[0003] Certain techniques can be used to improve the characteristics of the signal being transmitted. For example, spectrum shaping is used to improve the characteristics of the transmitted signal, and this shaping will also affect the reference signal. One spectrum shaping technique used is frequency domain spectrum shaping (FDSS), which applies a specific shape to the transmitted signal. The reference signal is affected by FDSS. Summary of the Invention

[0004] This section is intended to include examples and is not intended to be limiting.

[0005] In an exemplary embodiment, a method is disclosed that includes determining, by a node, a non-uniform reference signal configuration within an allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power profile for frequency-domain spectral shaping. The method also includes transmitting or receiving, by the node, a reference signal using the non-uniform reference signal configuration.

[0006] Another exemplary embodiment includes a computer program comprising instructions for performing the method of the previous paragraph when the computer program is executed on a device. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer-readable medium carrying instructions implemented therein for use with the device. Another example is a computer program according to this paragraph, wherein the program can be directly loaded into the internal memory of the device.

[0007] An exemplary apparatus includes one or more processors and one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus to at least perform: determining, by a node, a non-uniform reference signal configuration within an allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectral shaping; and transmitting or receiving, by the node, a reference signal using the non-uniform reference signal configuration.

[0008] An exemplary computer program product includes a computer-readable storage medium carrying instructions that, when executed by an apparatus, cause the apparatus to at least perform the following operations: determine, by a node, a non-uniform reference signal configuration within an allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency-domain spectral shaping; and transmit or receive a reference signal by the node using the non-uniform reference signal configuration.

[0009] In another exemplary embodiment, an apparatus includes means for determining, by a node, a non-uniform reference signal configuration within an allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency-domain spectral shaping; and transmitting or receiving, by the node, a reference signal using the non-uniform reference signal configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the attached figure:

[0011] Figure 1A is a block diagram of one possible and non-limiting exemplary system in which exemplary embodiments may be practiced;

[0012] Figure 1B is suitable for implementing Figure 1A An example of a block diagram of an apparatus of any node in;

[0013] Figure 2 is a block diagram of a DFT-s-OFDM transmitter with FDSS and spectrum spreading;

[0014] Figure 3A is a graph of the PSD of different FDSS filters that meet the requirements in the current specification;

[0015] Figure 3B Curves for conventional and FDSS with 25% expansion are shown for 192 and 256 PRBs;

[0016] Figure 4 is a flow chart for forming and using a non-uniform reference signal having an FDSS-based waveform;

[0017] Figure 5 is a flow chart of a first alternative scheme for forming and using a non-uniform reference signal having an FDSS-based waveform;

[0018] Figure 6 Shown for Figure 5 An example of a DMRS pattern allocation of a portion of

[0019] Figure 7is an illustration of sparse and dense DMRS patterns, such as a simple implementation using a symmetric extension of FDSS-SE;

[0020] Figure 8A is a flowchart illustrating signaling details for a first alternative using an FDSS-based waveform in the UL;

[0021] Figure 8B is a flowchart illustrating signaling-related details for using an FDSS-based waveform in the DL for the first alternative.

[0022] Figure 9A and Figure 9B Uniform and non-uniform examples for DMRS mapping are shown respectively;

[0023] Figure 10A and 10B The CMCDDF and PAPR CDDF of an example non-uniform DMRS pattern compared to uniform NR DMRS are shown, respectively;

[0024] Figure 11 is a flow chart of a second alternative for forming and using a non-uniform reference signal having an FDSS-based waveform;

[0025] Figure 12 is a flow chart of a third alternative for forming and using a non-uniform reference signal with an FDSS-based waveform. DETAILED DESCRIPTION

[0026] Abbreviations that may be found in the specification and / or drawings are defined below at the end of the detailed description section.

[0027] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this detailed description are exemplary embodiments provided to enable those skilled in the art to make or use the invention and are not intended to limit the scope of the invention, which is defined by the claims.

[0028] When more than one reference numeral, word, or acronym is used with " / " in this specification, and as generally used in this specification, " / " may be interpreted as "or," "and," or "both."

[0029] 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. It will be further understood that the terms "comprises," "including," "having," "includes," and / or "comprising" when used herein specify the presence of stated features, elements, and / or components, etc., but do not preclude the presence or addition of one or more other features, elements, elements, and / or combinations thereof.

[0030] Any flow chart herein (such as Figure 5 Figure 8 Figure 11 and Figure 12 Flowcharts in the drawings) or signaling diagrams are considered to be logical flow diagrams and illustrate the operation of exemplary methods, the results of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and / or interconnected components for performing functions according to exemplary embodiments. Block diagrams (such as Figure 1A 、 Figure 1B and Figure 2 ) may also illustrate the operation of an exemplary method, the result of execution of computer program instructions embodied on a computer readable memory, functions performed by logic implemented in hardware, and / or interconnected components for performing functions according to exemplary embodiments.

[0031] The exemplary embodiments herein describe techniques for forming and using a non-uniform reference signal having an FDSS-based waveform. Additional description of these techniques is presented after describing a system in which the exemplary embodiments may be used.

[0032] Go to Figure 1A , which shows a block diagram of one possible and non-limiting exemplary system in which exemplary embodiments may be practiced. A number of nodes are shown: User Equipment (UE) 110; Base Station 170; and Network Element(s) 190.

[0033] exist Figure 1A In the figure, user equipment (UE) 110, as one of the nodes, wirelessly communicates with wireless network 100 via wireless link 111. UE 110 is wireless and is typically a mobile device that can access a wireless network. UE 110 is shown having one or more antennas 128. Ellipses 101 indicate that there may be multiple UEs 110.

[0034] Base station 170, another node, provides wireless devices (such as UE 110) with access to wireless network 100. Base station 170 is shown with one or more antennas 158. There are many options for base station 170. Generally, base station 170 is a RAN node, and specifically can be a gNB, which is the primary term used herein. That is, base station 170 will be referred to as gNB 170. However, there are many options, including eNBs for base stations or options other than cellular systems. Base station 170 is not limited to a gNB and can be any device that provides wireless devices with access to a wireless network.

[0035] There are a number of configurations for base station 170. One such configuration is a "standalone" configuration, which includes all circuitry as part of a single unit and access to antenna 158. More commonly, the circuitry is split between one or more remote nodes 150 (with access to antenna 158) and a central node 160. For example, for 5G (also known as NR), a gNB may include a distributed unit (DU) or a DU and a radio unit (RU) as the remote node(s), and a central unit (CU) as the central node 160. For LTE, a base station 170 may include an eNB with a remote radio head as the remote node 150 and a baseband unit (BBU) as the central node 160. The remote node(s) 150 are coupled to the central node 160 via one or more links 171. Multiple remote nodes 150 may exist for a single central node 160, as indicated by ellipses 102 indicating multiple remote nodes and ellipses 103 indicating additional links 171. Remote node 150 is remote in the sense that it is contained in a physical housing that is different from the physical housing containing the corresponding central node 160. Link(s) 171 may be implemented using optical fiber, wireless technology, or any other technology for data communication.

[0036] Two or more base stations 170 communicate using, for example, link(s) 176. Link(s) 176 may be wired or wireless or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interfaces for other standards.

[0037] The wireless network 100 may include one or more network elements 190, as a third illustrated node, which may include core network functions and provide connectivity to a data network 191, such as a telephone network and / or a data communications network (e.g., the Internet), via one or more links 181. Such core network functions for 5G may include access and mobility management function(s) (AMFs) and / or user plane function(s) (UPFs) and / or session management function(s) (SMFs). Such core network functions for LTE may include MME (Mobility Management Entity) functions and / or SGW (Serving Gateway) functions. These are merely exemplary functions that may be supported by the network element(s) 190, and it is noted that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via a link 131. Link 131 may be implemented, for example, as an NG interface for 5G, an S1 interface for LTE, or other suitable interfaces for other standards.

[0038] In general, various embodiments of the user equipment 110 may include, but are not limited to, a cellular phone (such as a smartphone, a mobile phone, a cellular phone, a voice over Internet Protocol (IP) (VoIP) phone, and / or a wireless local ring phone, a tablet, a portable computer, a vehicle or an onboard device for, for example, wireless V2X (vehicle-to-everything) communication, an image capture device (such as a digital camera, a gaming device, a music storage and playback device), an Internet device (including an Internet of Things, IoT device), an IoT device with sensors and / or actuators for, for example, automation applications, and a portable unit or terminal incorporating a combination of these functions, a laptop embedded device (LEE), a laptop mounted device (LME), a universal serial bus (USB) dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of an industrial and / or automation process chain), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. That is, the UE 110 may be any terminal device capable of wireless communication. By way of example and not limitation, a UE may also be referred to as a communication device, a terminal device (MT), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT).

[0039] Go to Figure 1B , the diagram is suitable for implementing Figure 1A180 includes circuits interconnected by one or more buses 127, including one or more processors 120, one or more memories 125, one or more transceivers 130, one or more network (N / W) interfaces (I / F) 155, and user interface (UI) circuits and elements 157. Figure 1A This is an example of all nodes in the example, so some nodes may not have all circuits. For example, base station 170 may not have UI circuitry and element 157. All nodes may have additional circuitry not described here. Figure 1B Presented as an example only.

[0040] Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 can be address, data, and / or control buses and can include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical fiber or other optical communication devices, etc. The one or more transceivers 130 are connected to one or more antennas 105, which can be one of antenna 128 (from UE 110) or antenna 158 (from base station 170), and can communicate using wireless link 111.

[0041] The one or more memories 125 include computer program code 123. The device 180 includes a control module 140, which includes one or both of the parts 140-1 and / or 140-2, which can be implemented in a variety of ways. The control module 140 can be implemented in hardware as the control module 140-1, such as as part of the one or more processors 120. The control module 140-1 can also be implemented as an integrated circuit or through other hardware implementations such as a programmable gate array. In another example, the control module 140 can be implemented as a control module 140-2, which is implemented as computer program code (with corresponding instructions) 123 and executed by the one or more processors 120. For example, the one or more memories 125 store instructions that, when executed by the one or more processors 120, cause the device 180 to perform one or more operations as described herein. In addition, the one or more processors 120, the one or more memories 125, and the example algorithms (e.g., as flow charts and / or signaling diagrams) encoded as instructions, programs, or code are components for causing the operations described herein to be performed.

[0042] Network interface(s) (N / WI / F) 155 is a wired interface that communicates using link(s) 156, which may be fiber optic or other wired interfaces. Link(s) 156 may be from Figure 1A Link(s) 131 and / or 176. Figure 1AThe link(s) 131 and / or 176 may also be implemented using the transceiver(s) 130 and the corresponding wireless link(s) 111. The apparatus may include only the wireless transceiver(s) 130, only the network interfaces 155, or both the wireless transceiver(s) 130 and the network interfaces 155.

[0043] The device 180 may or may not include UI circuits and elements 157. These may include a display such as a touch screen, a speaker, or an interface element such as a headset. For example, a UE 110 that is a smartphone will typically include at least a touch screen and a speaker. The UI circuits and elements 157 may also include circuits for communicating with external UI elements (not shown) such as a display, keyboard, mouse, headset, etc.

[0044] The computer-readable memory 125 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, firmware, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The computer-readable memory 125 may be a device for performing a storage function. As non-limiting examples, the processor 120 may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The processor 120 may be a unit for performing functions such as controlling the device 180 and other functions described herein.

[0045] Having thus introduced a suitable but non-limiting technical context for practicing exemplary embodiments, exemplary embodiments will now be described in more detail.

[0046] Good coverage is crucial for cellular networks, and coverage enhancement is also being considered in NR Rel-18. This paper considers coverage enhancement by enabling higher UE transmit power, for example, by reducing the signal's peak-to-average power ratio (PAPR). In particular, spectrum spreading (SE) can be considered for frequency-domain spectrum shaping (FDSS). An example in this paper focuses on improving the gNB's ability to control FDSS with spectrum spreading.

[0047] For 5G NR waveforms, consider the following background. The modulated symbols and / or reference signals will be converted into a waveform, which is a baseband signal, before it is mixed into RF and transmitted over the air interface. In 5G NR, two waveforms have been specified, including:

[0048] 1) Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM), which is applicable to both uplink and downlink, and

[0049] 2) Discrete Fourier transform-spread orthogonal frequency division multiplexing (DFT-s-OFDM), which is applicable to uplink only in the current NR rel-18 and may be introduced later for DL.

[0050] DFT-s-OFDM only supports a single transmission layer (rank = 1) per user in the current NR rel-18 and may be increased in future releases, while CP-OFDM can support more than one layer (rank ≥ 1). This means that CP-OFDM can provide higher throughput and capacity than DFT-s-OFDM. In contrast, DFT-s-OFDM has a lower peak-to-average power ratio (PAPR) than its counterpart, which allows DFT-s-OFDM to be used with higher transmission power and therefore provide better coverage.

[0051] DFT-s-OFDM is generated by adding a transform precoding block before the processing block used to generate CP-OFDM. In fact, the transform precoding block is a fast Fourier transform (FFT) block that converts the time domain signal into the frequency domain signal.

[0052] Frequency Domain Spectral Shaping (FDSS) with and without spectrum spreading is now described. Although DFT-s-OFDM already provides lower PAPR than its counterpart CP-OFDM, 5G NR Release 15 (Rel-15) also introduced frequency domain spectral shaping for pi / 2 BPSK, and it may be introduced in Rel-18 for other modulations, where it is used to further reduce PAPR and / or reduce cubic metric (CM). This results in even lower maximum power reduction (MPR) and, therefore, higher maximum transmit power for coverage enhancement.

[0053] Spectrum shaping and spectrum spreading are two independent techniques; therefore, in general, shaping can be applied with or without spectrum spreading. For example, the current NR specification does not include spectrum spreading, which is being studied in Rel-18 as part of CovEnh WI (more details on this are given below). In this context, Figure 2 A block diagram of an NR UL transmitter applying both frequency domain spectrum shaping and spectrum spreading is shown in FIG. Figure 21 is a block diagram of a DFT-s-OFDM transmitter 133-1 with FDSS and spectrum spreading. Transmitter 133-1 receives modulated symbols 205 as input and forms a Tx signal 275 as output. Modulated symbols 205 pass through a serial-to-parallel (S / P) converter 210, then an M-point DFT 330, after which symmetric spreading 230 is applied. An FDSS function 240 is performed, followed by an N-point IFFT 250, followed by a parallel-to-serial (P / S) operation 280, and a CP is added by an add CP function 270 to form the output of Tx signal 275. Blocks 221, 231, and 241 of REs are shown for corresponding elements 220, 230, and 240. The ends 1 and 2 of the REs in block 230 are switched in block 231. The 1 and 2 for block 231 indicate the spreading that occurs by the symmetric spreading block 230.

[0054] In spectrum shaping, the transition band frequencies (e.g., 1 and 2, and frequencies closer to these frequencies in block 241) are weighted by FDSS function 240 before being mapped to the IFFT input. FDSS with spectrum spreading has additional cyclic extension blocks (see 1 and 2 of blocks 241), which results in excess frequency band. See R1-050702, "DFT-Spread OFDM with PulseShaping Filter in Frequency Domain in Evolved UTRA Uplink," NTT DoCoMo, NEC, Sharp, 3GPP TSG RAN WG1 #42 on LTE, London, UK, August 29–September 2, 2005.

[0055] exist Figure 2 , use the following parameters and definitions:

[0056] 1) In-band size: RE occupied after the DFT block, i.e. Figure 2 The M in.

[0057] 2) Excess Band Size: The amount of REs used for spectrum expansion, i.e., Figure 2 (QM) in.

[0058] 3) Total allocation size (in-band size + excess band size): REs occupied after the "symmetric extension block", i.e., Figure 2 Q in.

[0059] The amount of expansion can be represented by an expansion factor α: α = (QM) / Q (ie, excess bandwidth size / total allocation size). It should also be noted that the examples herein are not limited to Figure 2 For example, other extension methods are possible, and in addition to symmetric extension there may be cyclic extension or any cyclic shift plus symmetric extension.

[0060] Spread spectrum offers several advantages. First, it can reduce PAPR because the effective pulses have a larger time interval. Second, it can reduce intersymbol interference caused by the introduction of FDSS. Finally, because the excess band also carries in-band duplicate data or other redundant data for Rx, spread spectrum may or may not be used by the gNB receiver. However, when spread spectrum is used, it can further improve frequency diversity when the excess band contains copies of in-band data. The lack of the shaping function of spread spectrum means a trade-off between demodulation performance and Tx power gain. See the following: (1) R1-1709002, “On spectrum shaping for uplink Pi / 2BPSK with DFT-S-OFDM,” Nokia, Alcatel-Lucent Shanghai Bell, 3GPP TSG-RAN WG1#89 Meeting, Hangzhou, China, May 15-19, 2017; (2) R4-1714191, “Further Link Results for p / 2BPSK DFT-S-OFDM Waveform with Spectrum Shaping and MMSE Receiver,” IITH, 3GPP TSG RAN WG4#85 Meeting, Reno, USA, November 27-December 1, 2017; (3) R1-1705060, “Performance evaluation for pi / 2BPSKwith FDSS”; and R4-1710213, “On the detection performance of pi / 2-BPSK DFT-s-OFDM with transparent shaping,” Huawei, HiSilicon, 3GPP TSG-RAN WG4#84bis meeting, Dubrovnik, Croatia, October 9–13, 2017. At the same time, shaping with spectrum spreading also presents a trade-off between spectral efficiency and transmit power gain. See R1-050702, “DFT-Spread OFDM with Pulse Shaping Filter in Frequency Domain in Evolved UTRA Uplink,” NTT DoCoMo, NEC, Sharp, 3GPP TSG RAN WG1#42 on LTE, London, UK, August 29–September 2, 2005.

[0061] In Rel-15, FDSS without spectrum spreading for DFT-s-OFDM was used only for pi / 2-BPSK modulation. In the Rel-17 study item on coverage enhancement, it was pointed out that the gain by applying FDSS to higher-order modulation techniques (e.g., QPSK) is lower than the gain when FDSS is applied to pi / 2-BPSK. See R1-2008703, Discussion on approaches and solutions for NR PUSCH coverage enhancement, Nokia, Nokia Shanghai Bell, 3GPP TSG RAN WG1. #103, online meeting, October 26-November 13, 2020. Given that Rel-18 aims to improve UL coverage, enhancements to other higher-order modulation techniques should also be considered. FDSS with spectrum spreading is a candidate solution to achieve this goal and can be stated as an enabler for coverage improvement in Rel-18.

[0062] Although FDSS is beneficial, it also has problems. One observation that led to the identification of the following problem is that when using FDSS with or without SE, the power distribution on different REs is not uniform, as shown in Figure 3A As shown, it shows the PSD for different filters that meet the RF requirements and spectrum flatness requirements (depending on whether SE is considered, which has been defined or is to be defined in RAN4). Figure 3A Different filters that can be used with FDSS are shown to indicate that the power of REs can change significantly between in-band and edge-band after applying FDSS, and this power change is transparent to the gNB because the filters are UE confidential. Figure 3A Different filters are shown, as well as the possible steepness in the transition between the center / middle band and the edge bands.

[0063] As an illustration, DFT-s-OFDM without FDSS can be represented as applying a filter with uniform constant power across all subcarriers (REs) (imagine Figure 3A There are similar Figure 3B ), and so by comparing these filters to the horizontal line of the same total power, one can notice the aggressivity of the filter mainly at the edge REs, where there is always some power reduction depending on the filter shape. The middle REs or center (around subcarrier index 48 of the 96 REs or 8 PRBs in this case) will always benefit from a power boost, see Figure 3B, where the PSD of FDSS-SE is compared to the PSD of a conventional signal without FDSS-SE at the same power. The square curve is the conventional curve, while the curve with a lower edge near the end of the band and a peak near 28 GHz is the FDSS with an expanded curve. Furthermore, the wider curve is for 256 PRBs, while the narrower curve is for 192 PRBs.

[0064] exist Figure 3A In Figure 1, more and less aggressive filters are also shown. These are in terms of shape. In the absence of shaping, the filter shape can be considered to be all ones (i.e., Figure 3A The 0dB straight line in FIG. 1 is shown in FIG. 1 . A more aggressive filter is one with tdFilt = [-0.335, 1.000, -0.335], and a less aggressive filter is one with tdFilt = [-0.200, 1.000, -0.200]. The more aggressive the filter, the higher the average attenuation of the frequency domain signal as it moves from the center to the edge, and the less aggressive the filter, the lower the average attenuation of the frequency domain signal as it moves from the center to the edge. As another example, an indication of the steepness of the transition from the center of the band to the edge of the band can be used to determine whether the filter is more aggressive or less aggressive.

[0065] It should also be noted that current 5G NR signaling allows one DMRS density and pattern for all PRBs allocated to a UE and does not provide means for configuring / adjusting the DMRS pattern of (multiple) band segments within the total band allocation.

[0066] It can be observed that the current 5G NR uniform DMRS pattern is not optimal for FDSS-based waveforms. This is mainly due to the lower average power (e.g., lower EPRE or SNR) of the 5G NR DMRS after FDSS filtering, which affects the channel estimation accuracy and thus affects the detection performance at the receiver due to inaccurate channel estimation using noisier DMRS. However, simply considering the different densities between the in-band and excess bands is not the optimal DMRS configuration for best performance.

[0067] Therefore, one issue is how to optimize frequency domain reference signal allocation with FDSS-based waveforms, for example, to enhance channel estimation accuracy and improve coverage, and potentially save UE power in some cases.

[0068] The following are further observations relevant to the issues considered in this paper.

[0069] 1) For FDSS with / without spectrum spreading (SE), the power distribution varies significantly with different filters.

[0070] 2) The filters for FDSS are transparent to the gNB and are not defined in the specification. The gNB is unaware of the filter power profile applied at the UE.

[0071] 3) Filter the reference signal (eg, DMRS) using the same FDSS filter used for the data to perform joint channel and filter estimation at the receiver side.

[0072] 4) The UE may use different filters with different configurations (eg, spectrum spreading factors, etc.).

[0073] 5) The gNB receiver may partially or fully use the excess band containing a partial copy (i.e., a portion) of the in-band data. That is, the gNB makes an Rx decision on how much of the excess band the gNB will use, e.g., because edge subcarriers have very low power due to shaping, and the gNB may decide not to use them for demodulation / estimation.

[0074] a) When using aggressive filters resulting in excess band power being too low, the gNB receiver performance gain is negligible.

[0075] b) The gNB can choose the best trade-off between performance gain and additional computational complexity of the advanced receiver by partially or completely dropping the excess frequency band.

[0076] c) If the excess band is dropped, the transmitted RS (eg, DMRS) is not used.

[0077] The examples herein may address some or all of these issues. As an overview, the examples herein provide alternatives applicable to FDSS with or without SE. The example techniques herein are applicable whenever filtering affects the transmit power on the allocated frequency band (or REs), regardless of whether the filtering is:

[0078] 1) In Figure 2 In the frequency shown or in the time domain;

[0079] 2) With Figure 2 Spectrum spreading (SE) or without SE;

[0080] 3) With Figure 2 Symmetric expansion or other possible expansion methods in (if any);

[0081] 4) With Figure 2 DFT-s-OFDM in , or with other variants of DFT-s-OFDM (e.g., KT, known tail, alternative CP, or with UW, unique word), or with any other waveform (e.g. Figure 2In , CP-OFDM of DFT is deactivated by transform precoding).

[0082] This summary is partially incorporated by reference Figure 4 To describe, Figure 4 This is a flow chart for forming and using a non-uniform reference signal with an FDSS-based waveform. An example proposes non-uniform frequency-domain RS across the entire allocated BW (e.g., FDRA) according to the UE filter power distribution. To this end, due to the increased improvement in the average SNR of the RS with the FDSS filter with non-uniform power, better channel estimation accuracy is achieved, thereby enhancing coverage (recall that FDSS with or without SE is used in low coverage scenarios). Example features include the following.

[0083] 1) The UE (or gNB, if the UE FDSS filter power variation details are available) determines a non-uniform RS configuration pattern over the entire allocated band or within different segments of the total allocation based on the FDSS filter power. See block 405. Note that this may be generalized: the UE may be the transmitter (Tx) and the gNB may be the receiver (Rx); alternatively, the gNB may be the Tx and the UE may be the Rx. Note that this generalization may be implemented in this flowchart or other flowcharts (e.g., in block 440, the UE may be the Tx), but the gNB is the master node controlling some operations, such as performing configuration or confirmation in block 450. The FDSS filter power may be understood to mean at least the FDSS filter shape (e.g., Figure 3A ). Therefore, the RS configuration may depend on the filter shape applied by the UE (where the filter shape defines the power distribution of the subcarriers). In summary, non-uniform RS configurations include non-uniform RS pattern (hereinafter referred to as Alternative 1), non-uniform RS power adaptation (Alternative 2), and non-uniform RS pattern and power adaptation (Alternative 3).

[0084] As shown in block 410, the non-uniform RS configuration may consider at least one of the following:

[0085] a) A denser RS ​​(e.g., block DMRS) in the middle of the inner-band and a sparser RS ​​distribution at the outer-band. The inner-band and excess-band can be divided into smaller band segments to adjust RS with smaller band granularity. This will also be referred to below as Figure 5 、 Figure 6 、 Figure 7 Figure 8 Figure 9B 、 Figure 10A and Figure 10B See block 410.

[0086] b) The RS density gradually decreases as the frequency segments move from the center of the band to the edge of the frequency allocation. This is also part of Alternative 1, see e.g. Figure 6 and variant A1 as an example with gradual RS density reduction (alternative 1). See block 420.

[0087] c) Non-uniform power adaptation of RS to partially offset the power of FDSS filter, as in alternative 2 and Figure 11 See block 423. In more detail, this may include performing non-uniform power adaptation on the REs carrying RSs on the allocated frequency band or segments of the frequency band to at least partially balance the FDSS filters (e.g., the power adaptation may be power ramping up / down on some segments within the allocated frequency band).

[0088] This is also described below as Figure 11 See block 420 as part of Alternative 2.

[0089] d) A combination of (a) (Alternative 1) and (b) (Alternative 2). This includes non-uniform RS pattern and power adaptation. See box 425 and Figure 12 .

[0090] e) Implicit indication of RS pattern for band segments within the inner band according to the outer band pattern and the spreading method with FDSS-SE.

[0091] f) In one embodiment, a time-varying DMRS pattern over consecutive transmissions / repetitions within the channel coherence time to allow estimation of all bins of the filter, especially if the filter is too aggressive (this can be performed by alternating between RS patterns covering different REs). See block 435.

[0092] 2) In block 440, the UE implicitly or explicitly indicates to the gNB its preference for non-uniform frequency-domain RS configurations (e.g., DMRS) for its allocation over the entire allocated BW or over different segments within the allocated BW, based on its confidentiality filter (e.g., and possibly its extended implementation with FDSS-SE, which may include symmetric extensions, etc.). The FDSS filter used for the Tx (in this example, which may be the UE) is transparent to the Rx (here, the gNB) and is neither specified nor reported in the standard: the filter is therefore confidential for the transmitter (here, the UE) to implement FDSS-SE.

[0093] 3) The gNB may also indicate, for example, a shaping limit at which the pattern should be changed. See block 445. The shaping limit may be, for example, in the frequency domain at which the non-uniform pattern should be changed (e.g., reduce / increase density and / or reduce / increase power). However, the shaping limit is not limited to the frequency domain and may include the time domain, where the pattern needs to be changed (e.g., after some symbols or slots, e.g., with a time-varying DMRS pattern), or when the UE's switching FDSS filter meets some constraints / conditions (e.g., edge band attenuation > X dB or in-band boost > Y dB, or any condition defining a power range for at least one band segment). Furthermore, the shaping limit may be determined by, for example Figure 3A A simple example is as follows: if filter shape > threshold, apply pattern 1; and if filter shape <= threshold, apply pattern 2. As also explained above, restrictions can be defined separately for a portion of a frequency band.

[0094] 4) gNB signaling may be performed to configure / confirm the appropriate non-uniform RS configuration across several PRBs. For example, the gNB may define and indicate one or more additional parameters beyond existing 5G NR parameters to enable non-uniform RS configuration. See block 450.

[0095] In block 460 , the node transmits or receives a reference signal across the entire allocated frequency band using a non-uniform reference signal configuration.

[0096] Note that RS is usually pre-configured between Tx and Rx, and Rx will need to perform configured power adaptation of RS symbols to scale them accordingly. That is, Rx( Figure 4 The UE in the example of can adjust the power of the reference signal learned from the non-uniform RS configuration. This can be combined with Figure 4 424 to execute.

[0097] Now that an overview has been provided, more details are provided below. We propose to improve and optimize frequency-domain RS (e.g., DMRS) allocation across the FDRA to exploit the non-uniform power distribution on REs with FDSS-based waveforms. A proposed scheme allows for a 1+dB improvement in the average SNR of the DMRS by leveraging the higher power-boosted spectrum segments of the FDSS, thereby enhancing the channel estimation accuracy and coverage of FDSS with or without (w / o)SE.

[0098] The solution is divided into three examples, called alternatives. While these are not the only alternatives, they help provide guidance on possible implementations.

[0099] Alternative 1: Non-uniform pattern of frequency-domain RS and related signaling for FDSS with or without SE.

[0100] The alternative is a frequency domain non-uniform RS proposal using FDSS with or without SE. The main concepts include the following. Also refer to Figure 5 , Figure 5 is a flow chart of a first alternative approach for forming and using a non-uniform reference signal with an FDSS-based waveform.

[0101] In block 505, a non-uniform RS pattern is allocated based on the filter power distribution. For example, a non-uniform RS pattern (e.g., DMRS) can be allocated in the middle RE (e.g., block DMRS), and a sparser RS ​​(e.g., DMRS) may be allocated at the edge of the (e.g., total) bandwidth allocation. Using these techniques, the average SNR of the RS is higher due to the additional power boost of the FDSS, and the overall channel estimation accuracy is improved. This can be performed by maintaining the same RS overhead (variant A) or not maintaining the same RS overhead (variant B). It should also be noted that the non-uniform RS pattern can be across the entire allocated frequency band or within different frequency band segments of the total allocation.

[0102] A number of examples are now described.

[0103] In Example 1, see block 510: dense DMRS or block DMRS in the middle band, and distributed / sparse RS used at the edge. Edge RS can be sparser than NR to maintain the same total RS overhead and avoid power reduction per RS. A combination of block and distributed RS can also exist (i.e., multiple blocks and blocks can also have different sizes).

[0104] Example 1A, see block 515: progressively increasing span at the edge, e.g., the span between RSs can increase as the edge is approached (e.g., spanRS_InnerMiddle=0, spanRS_OuterMiddleRS=2, spanRS_edge=3, ...). The increasing RS span option may be beneficial in situations where the allocated bandwidth is larger, allowing for denser signal distribution in the middle and / or reduced density at the low-power edge. This is variant A1.

[0105] Example 1B, see box 520: Constant span / gap at edge band segments: With block DMRS in the middle, the span or gap between RSs at the edge can be constant (eg, span=2 or higher). This is variant A2.

[0106] See also Figure 6 , which shows the Figure 5 part (i.e., the already described Figure 5Line 650 represents an example of DMRS pattern allocation. Figure 3A A rough plot of the power distribution of the example filter across the entire allocated frequency band 660 is shown. Reference numeral 610 indicates the current DMRS allocation in REs. Reference numeral 620 indicates variant A1, in which the same RS overhead exists while increasing the span or gap. This corresponds to block 515. Variant A1 has a block of continuous RSs (DMRSs in this example) in REs in the middle 662 of the entire allocated frequency band 660, but then increases the span / gaps in REs from there toward the edges 661, 663 of the entire allocated frequency band 660 (the span / gaps between REs are marked with "1"). Reference numeral 630 is variant A2, in which the span or spacing between RSs remains constant while maintaining the same RS overhead. This corresponds to block 520. Variant A2 has a block of continuous RS (DMRS in this example) in REs in the middle 662 of the entire allocated frequency band 660, and then a constant span / gap (the span / gap between REs marked with "1") from there towards the edges 661, 663 of the entire allocated frequency band 660. Note that Figure 6 The example in shows a symmetrical pattern around the middle 662, but symmetry is just an example and the pattern may not be symmetrical on the two sides.

[0107] Example 1C, see Figure 5 Box 525: Consider a simple implementation of the symmetric extension of FDSS-SE. Figure 7 , which shows the entire allocated frequency band 660, with sparse DMRS in two symmetrical extensions and dense DMRS in the middle. The in-band portion is also shown. This option can allocate sparse reference signals at both the inner and outer edges of the band (smaller than the in-band center and possibly different between the left and right edges).

[0108] Example 2: Keep RS allocation same as NR at the edges and allocate more RS in the middle: RS overhead is higher and hence a good trade-off can be chosen to benefit from the power boost per RS ​​and the number of RSs to get good estimation accuracy. See block 530. This is also Figure 6 640, in which lower RS ​​power is achieved by creating a block DMRS in the middle of the span, using additional RS overhead. Variant B has a block of continuous RS (DMRS in this example) in REs in the middle 662 of the entire allocated frequency band 660, and then maintains a constant span / gap of the individual reference signals from there towards the edges 661, 663 of the entire allocated frequency band 660 (the span / gap between REs marked with "1").

[0109] Using either example of non-uniform frequency domain RS covering the entire FDRA, the following are additional examples.

[0110] In block 535 , the RSs may be distributed asymmetrically between the left and right edges, eg, to allow the filter to obtain more estimates at different frequencies (assuming the FDSS filter is symmetrical).

[0111] In block 540 , RSs may be distributed symmetrically on the left / right edges.

[0112] In block 545 , the RS pattern may be determined based on the SE factor α, channel profile, selectivity, and the like.

[0113] In block 550, alternating or time-varying RS patterns between different RS patterns may be used in successive transmissions within the channel coherence time (e.g., to estimate all frequencies). Group-based DMRS bundling may be performed between symbols using the same RS pattern, and joint filtering and channel estimation over multiple slots may use all groups of bundled DMRS. This option may be used with or without dense / sparse RSs in the middle / edge REs.

[0114] These schemes are directly applicable to any frequency-domain RS of FDSS with or without SE and are not limited to DMRS. That is, whenever filtering affects the transmit power on the allocated frequency band (or RE), the example techniques herein are applicable, regardless of whether the filtering is in the following cases: in the frequency domain or in the time domain; with spectrum spreading (SE) or without SE; with symmetric spreading or other possible spreading methods (if any); or with DFT-s-OFDM or other variants of DFT-s-OFDM or with any other waveform.

[0115] Below and Figure 8A The signaling related details for using Alternative 1 with FDSS based waveform in UL are shown in FIG.

[0116] In block 805, the UE reports its capability to use non-uniform RS, such as:

[0117] a) by possibly indicating a preferred DMRS pattern or other implicit indication, see block 810, or

[0118] b) Explicitly, in particular when the gNB determines the best DMRS pattern based on known UE filter details (e.g., estimated from previous transmissions, or based on any filter details reported by the UE during previous exchanges). See block 815.

[0119] In block 820, the UE determines and then implicitly or explicitly indicates the referenced DMRS pattern. Another possibility is that, referring to block 825, the gNB determines a non-uniform RS pattern based on received details related to the UE filters or estimated channel and filter responses.

[0120] In block 830, the gNB confirms the preferred UE DMRS pattern, or configures a non-uniform RS configuration across all allocated bands (e.g., different patterns / densities / powers for different band segments), where the configuration may include one or more of the following.

[0121] 1) Additional DMRS pattern / density / power parameters for different frequency band segments within the total allocated bandwidth or at least only within the frequency band, see block 835;

[0122] 2) density parameters (e.g., deltaDMRSDensity) between consecutive PRBs or band segments, where primary (inner) and secondary (outer) in-band / excess bands may be defined (e.g., primary as middle in-band, secondary as in-band outer equal to excess band size, left / right excess band, etc.), see block 840;

[0123] 3) Parameters for selecting a predefined non-uniform RS pattern across the entire allocated frequency band, see block 845;

[0124] 4) A single DCI bit used to enable / disable in-band or intra-block DMRS, or to confirm / reject the preferred DMRS pattern reported by the UE, see block 850;

[0125] 5) A single bit or a small number of bits indicating to the gNB receiver if the gNB partially / completely drops the excess band, see block 855 (“completely” means removing all RSs in the excess band, thereby saving UE power or increasing RS power within the band while keeping the per-symbol power the same; using 50% of the excess band means the UE drops RSs in the outer 50% of the excess band and adjusts accordingly). This can be achieved via higher layer signaling;

[0126] 6) If and only if sufficient filter details are known from a previous UE-gNB exchange, all parameters may be transmitted via higher layer signaling, see block 860. Otherwise, it may be more appropriate to use some bits in DCI format 0_0 or 1_1, or possibly reuse DCI format 2_4 only for RS transmission cancellation, rather than general UL transmission cancellation (e.g., format 2_4 is used to inform the UE of the PRBs and OFDM symbols in which the corresponding UL transmission from the UE is cancelled (UL reused for RS UL)).

[0127] Below and Figure 8BThe signaling details of using alternative 1 with FDSS-based waveforms in the DL are shown in FIG. This process is similar to the process in FIG. 8 , so only the changes are described here. Figure 8A In , the UE is the transmitter and the gNB (e.g., master node) is the receiver. Figure 8B In these examples, the UE is the receiver and the gNB (e.g., master node) is the transmitter. In these examples, the term "master node" refers to the gNB, regardless of whether the gNB is a transmitter or a receiver.

[0128] Claims 805, 810 and 815 are similar to Figure 8A Those in Figure 8B In block 815-1, it is assumed that the gNB determines the optimal DMRS pattern based on its transmit FDSS filters. In block 820, the UE may still determine and then indicate the DMRS pattern. For clarity, the UE's determination and indication of possible DMRS patterns may be based on its implementation (e.g., supported RS configurations in its estimator) or previously received DL signals from the gNB with FDSS-based waveforms (e.g., based on Rx power estimates for REs at different locations). In this DL example, block 820 is not based on the UE's Rx filters. Instead, the relevant filters that determine the reference signal configuration in the UL and DL are primarily the filters on the transmitter side (here, the base station in the DL), so the Tx device needs to indicate such information, and the gNB will confirm it or configure other relevant RS patterns. Therefore, in block 825-1, the gNB determines a non-uniform RS pattern based on its filters and / or received UE preferences (if any). If the UE executes block 820, the gNB may confirm the preferred UE DMRS pattern in block 830. Otherwise (or if the gNB wants to use another RS ​​pattern), the gNB configures a non-uniform RS configuration across all allocated bands in block 830. The configuration may include any of blocks 835 to 860, except that in block 860-1, it is assumed that the gNB and UE do not exchange the UE's filter details.

[0129] An example of using DMRS mapping is shown in Figure 9A and 9B As shown in Figure 9A and 9B Uniform and non-uniform examples for DMRS mapping are shown, respectively. Figure 9A The NR DMRS power of the FDSS filter is shown (e.g., 1 DMRS every other RE). Figure 9BThe following example shows a non-uniform DMRS pattern, Example 1, which is denser in the center and sparser at the edges, with the same DMRS overhead. PAPR and CM are reduced by only approximately 0.08 dB, while the average DMRS SNR is improved by 1.4 dB at the same RS overhead. This is because more DMRS symbols are allocated to the center of the band, which increases the average power of the DMRS REs compared to the conventional pattern.

[0130] In more detail, Figure 9A An example of 5G NR DMRS using an example filter and uniform DMRS across the band is shown, while Figure 9B It can be noticed that the power of DMRS is much lower at the edges and much higher at the center in both sub-figures, compared to the traditional DMRS without FDSS (which can be represented by a constant power level line at 1 for all REs). Figure 9A It can be clearly seen that most of the DMRS (along Figure 9A The circle of the line in the figure is lower than the horizontal line at 1 representing the conventional RE power, which is non-optimal. However, by using an example of a non-uniform DMRS pattern according to the filter shape, more power can be collected with denser DMRS in the center, and thus the channel estimation accuracy and Rx performance (e.g., compared to the conventional RE power) can be enhanced. Figure 9A compared to, Figure 9B This results in a 1.4dB average power increase for DMRS). Figure 9B This power boost gain in (above the conventional level of 1 without FDSS-SE) is achieved by concentrating more DMRS REs near the center, as shown along Figure 9B The X marks the position of the line in the Figure 9B The non-uniform pattern (relative to Figure 9A uniform pattern) to achieve higher SNR and EPRE, and can reduce the impact of noise to achieve better channel estimation accuracy. Note that Figure 9A and 9B The numbers of X and circle marks in are the same, respectively, which means that there is the same DMRS overhead in both figures.

[0131] Another alternative to the power boost of DMRS as we approach the edge is to balance the power attenuation of the filter mainly at the edge.

[0132] Figure 10A and Figure 10BThe CM and PAPR CDDFs for an example non-uniform DMRS pattern compared to uniform NR DMRS are shown, respectively. This non-uniform DMRS pattern example has QPSK, FDSS-SE = 25%, and 2 DMRS symbols. The differences are very slight: CM is 0.0780 and PAPR is 0.08. However, increasing the average RS power by more than 1 dB will significantly enhance performance and thus achieve a positive net coverage gain.

[0133] Alternative 2: RS power adaptation from inner band center outward (e.g., ramp up / down)

[0134] refer to Figure 11 Describe the alternative. Figure 11 is a flow chart of a second alternative approach for forming and using a non-uniform reference signal with an FDSS-based waveform.

[0135] In block 1105 , incremental power adaptation (ramping / ramping) is determined for the DMRS to partially offset FDSS filter power variations, even RS power attenuation at the edges within the band, and thus minimize the difference compared to uniform power.

[0136] This will allow for quasi-similar SNRs for all RSs within the allocated bandwidth (due to reduced power non-uniformity of RSs due to FDSS) and generally at least reduce the SNR gap between RSs. Consequently, this results in similar estimation accuracy across all frequencies (higher accuracy for outer band segments) and potentially better overall accuracy while maintaining the joint filter and channel estimate based on the FDSS waveform. This approach can help, for example, in deep fading, where the channel can severely attenuate some RSs at the edges (even in the outer bands) at lower power than without the FDSS-based waveform, and thus result in significant performance loss at low SNRs.

[0137] As indicated by block 1110, such DMRS power adaptation (e.g., increasing / decreasing) across REs requires a filter power profile indication of the transmitter (Tx) to achieve the above goals, or direct DMRS power adaptation (e.g., increasing / decreasing) by the Tx, and thus corresponding Tx auxiliary signaling is used. Block 1110 also indicates that power adaptation can be applied only to RS in the RE, not to data in the RE, or to both RS in the RE and data in the RE.

[0138] Block 1115 indicates that the gNB can use the new signaling parameters to configure / confirm power adaptation for DMRS. After this configuration or confirmation 1115, the power adaptation (e.g., ramp up / down) will be known to both Tx / Rx in block 1120, and Rx can adjust the joint filter and channel estimation accordingly. As previously described, RS is typically pre-configured between Tx and Rx, and Rx will need to perform the configured power adaptation of the RS symbols to scale them accordingly. That is, Rx ( Figure 11 Tx in the example of can adjust the power of the reference signal learned from the non-uniform reference signal configuration. This can be combined with Figure 11 1115 and 1120 to execute.

[0139] Alternative 3: Combination of the above alternatives

[0140] For alternative 3, refer to Figure 12 Describe the alternative, Figure 12 1 is a flow chart of a third alternative for forming and using a non-uniform reference signal with an FDSS-based waveform. Block 1205 indicates that Alternative 3 is a combination of Alternative 1 and Alternative 2. That is, Alternative 3 combines the non-uniform RS pattern of Alternative 1 and the power adaptation of Alternative 2.

[0141] In block 1210, alternative 2 allows for similar estimation accuracy across all frequencies. Furthermore, alternative 1 can be used after alternative 2, see block 1215. This can reduce the overhead of useless RSs (e.g., in excess bands) and still achieve some power improvement relative to the residual difference caused by the granularity of the RSs with ramped power.

[0142] Without in any way limiting the scope, interpretation, or application of the claims appearing below, technical effects and advantages of one or more exemplary embodiments of the present disclosure include: UE-assisted gNB selection of the optimal RS non-uniform pattern and / or RS power control to optimize channel estimation and coverage. Another technical effect and advantage of one or more exemplary embodiments of the present disclosure is: when the gNB receiver fully / partially drops excess band, which may be reflected by the configured non-uniform DMRS pattern, the UE saves UE power by avoiding transmission of unused RS. Another technical effect and advantage of one or more exemplary embodiments of the present disclosure is: additional power boosting of existing RS usage can be performed (e.g., allocating 8 RBs, including 2 as excess bands -> completely dropping RS in the excess bands results in a 33% RS power boost within the 6 RBs within the band). Note that the gNB is aware of the used portion of the excess band reported by the UE and can scale its estimate based on this additional power boost. Another technical effect and advantage of one or more exemplary embodiments of the present disclosure is: the UE can maintain the confidentiality of its FDSS implementation. Another technical effect and advantage of one or more example embodiments of the present disclosure is that by adjusting the non-uniform RS allocation on FDRA according to the terminal-specific filter power distribution, the base station can enhance coverage by improving the average SNR of the reference signal.

[0143] The following are additional examples.

[0144] Example 1. A method comprising:

[0145] Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; and

[0146] A reference signal is transmitted or received by a node using a non-uniform reference signal configuration.

[0147] Example 2. The method of Example 1, wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band.

[0148] Example 3. The method of any of Examples 1 or 2, wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation.

[0149] Example 4. The method according to any one of Examples 1 to 3, wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

[0150] Example 5. The method of Example 4, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of an inner frequency band of the allocated frequency band, or a sparser reference signal distribution at an outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at an outer frequency band.

[0151] Example 6. The method of Example 5, wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

[0152] Example 7. The method of Example 6, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

[0153] Example 8. The method according to any one of Examples 1 to 3, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of the reference signal.

[0154] Example 9. The method of Example 8, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

[0155] Example 10. The method of any one of Examples 8 to 9, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

[0156] Example 11. The method according to Examples 4 to 10, wherein the non-uniform reference signal configuration comprises a combination of a non-uniform RS pattern according to any one of Examples 4 to 7 and a non-uniform power adaptation according to any one of Examples 8 to 10.

[0157] Example 12. The method of any one of Examples 1 to 11, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to the base station.

[0158] Example 13. The method of any one of Examples 1 to 11, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from the user equipment, the base station confirming or configuring the non-uniform reference signal configuration based in part on the received indication.

[0159] Example 14. The method of any one of Examples 1 to 11, wherein the node performs transmitting a reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by the base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

[0160] Example 15. The method of any one of Examples 1 to 11, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is used by the node to determine a reference signal position on the received signal, or adjust a power of a reference signal learned from the non-uniform reference signal configuration, or determine a reference signal position on the received signal and adjust a power of a reference signal learned from the non-uniform reference signal configuration.

[0161] Example 16. The method of any of Examples 1 to 11, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is considered in receiver estimation to derive at least a joint filter and a channel estimate.

[0162] Example 17. The method according to any one of Examples 1 to 16, wherein the node is a user equipment, wherein the determination of the non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from the network.

[0163] Example 18. A computer program comprising instructions for performing the method of any one of Examples 1 to 17 when the computer program is run on a device.

[0164] Example 19. The computer program according to example 18, wherein the computer program is a computer program product comprising a computer readable medium bearing instructions embodied therein for use with the apparatus.

[0165] Example 20. The computer program according to example 18, wherein the computer program is directly loadable into an internal memory of the device.

[0166] Example 21. An apparatus comprising means for:

[0167] Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; and

[0168] A reference signal is transmitted or received by a node using a non-uniform reference signal configuration.

[0169] Example 22. The apparatus of Example 21, wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band.

[0170] Example 23. The apparatus of any of Examples 21 or 22, wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation.

[0171] Example 24. The apparatus according to any one of Examples 21 to 23, wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

[0172] Example 25. The apparatus of Example 24, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of an inner frequency band of the allocated frequency band, or a sparser reference signal distribution at an outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at an outer frequency band.

[0173] Example 26. The apparatus of Example 25, wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

[0174] Example 27. The apparatus of Example 26, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

[0175] Example 28. The apparatus according to any one of Examples 21 to 23, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of the reference signal.

[0176] Example 29. The apparatus according to Example 28, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

[0177] Example 30. The apparatus according to any one of Examples 28 to 29, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

[0178] Example 31. The apparatus according to any one of Examples 24 to 30, wherein the non-uniform reference signal configuration comprises a combination of a non-uniform RS pattern according to any one of Examples 24 to 27 and a non-uniform power adaptation according to any one of Examples 28 to 30.

[0179] Example 32. The apparatus according to any one of Examples 21 to 31, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to the base station.

[0180] Example 33. The apparatus of any one of Examples 21 to 31, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from the user equipment, and the base station confirms or configures the non-uniform reference signal configuration based in part on the received indication.

[0181] Example 34. The apparatus according to any one of Examples 21 to 31, wherein the node performs transmitting a reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by the base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

[0182] Example 35. The apparatus of any one of Examples 21 to 31, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is used by the node to determine a reference signal position on a received signal, or adjust a power of a reference signal learned from the non-uniform reference signal configuration, or determine a reference signal position on a received signal and adjust a power of a reference signal learned from the non-uniform reference signal configuration.

[0183] Example 36. The apparatus according to any of Examples 21 to 31, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is considered in receiver estimation to derive at least a joint filter and channel estimate.

[0184] Example 37. The apparatus according to any one of Examples 21 to 36, wherein the node is a user equipment, wherein the determination of the non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from the network.

[0185] Example 38. The apparatus of any preceding apparatus example, wherein the component comprises:

[0186] at least one processor; and

[0187] At least one memory storing instructions that, when executed by at least one processor, cause execution of the apparatus.

[0188] Example 39. An apparatus comprising:

[0189] one or more processors; and

[0190] One or more memories storing instructions that, when executed by one or more processors, cause the apparatus to at least:

[0191] Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; and

[0192] A reference signal is transmitted or received by a node using a non-uniform reference signal configuration.

[0193] Example 40. The apparatus of Example 39, wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band.

[0194] Example 41. The apparatus of any of Examples 39 or 40, wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation.

[0195] Example 42. The apparatus according to any one of Examples 39 to 41, wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

[0196] Example 43. The apparatus of Example 42, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of an inner frequency band of the allocated frequency band, or a sparser reference signal distribution at an outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at the outer frequency band.

[0197] Example 44. The apparatus according to example 43, wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

[0198] Example 45. The apparatus of Example 44, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

[0199] Example 46. The apparatus according to any one of Examples 39 to 41, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of the reference signal.

[0200] Example 47. The apparatus according to Example 46, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

[0201] Example 48. The apparatus according to any one of Examples 46 to 47, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

[0202] Example 49. The apparatus according to Examples 42 to 48, wherein the non-uniform reference signal configuration comprises a combination of the non-uniform RS pattern from any one of Examples 4 to 7 and the non-uniform power adaptation according to any one of Examples 8 to 10.

[0203] Example 50. The apparatus according to any one of Examples 39 to 49, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to the base station.

[0204] Example 51. The apparatus of any one of Examples 39 to 49, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from a user equipment, and the base station confirms or configures the non-uniform reference signal configuration based in part on the received indication.

[0205] Example 52. The apparatus according to any one of Examples 39 to 49, wherein the node performs transmitting a reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by the base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

[0206] Example 53. The apparatus of any one of Examples 39 to 49, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is used by the node to determine a reference signal position on a received signal, or adjust a power of a reference signal learned from the non-uniform reference signal configuration, or determine a reference signal position on a received signal and adjust a power of a reference signal learned from the non-uniform reference signal configuration.

[0207] Example 54. The apparatus of any of Examples 39 to 49, wherein the node performs receiving a reference signal, wherein a non-uniform reference signal configuration is considered in receiver estimation to derive at least a joint filter and channel estimate.

[0208] Example 55. The apparatus according to any one of Examples 39 to 54, wherein the node is a user equipment, wherein the determination of the non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from the network.

[0209] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0210] (a) hardware circuit implementation only (such as analog implementation only and / or digital circuitry) and

[0211] (b) a combination of hardware circuitry and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware; and (ii) any portion of a hardware processor (including a digital signal processor), software, and memory with software that work together to enable a device (such as a mobile phone or server) to perform various functions; and

[0212] (c) A hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that requires software (eg, firmware) to operate, but which may not be present when not required for operation.

[0213] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers implementations of merely a hardware circuit or processor (or multiple processors), or portions of a hardware circuit or processor, and their accompanying software and / or firmware. For example, the term circuitry also covers a baseband integrated circuit or processor integrated circuit used in a mobile device or similar integrated circuit in a server, cellular network device, or other computing or networking device, if applicable to the particular claim element.

[0214] The embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., application specific integrated circuits), or a combination of software and hardware. In example embodiments, the software (e.g., application logic, instruction sets) is maintained on any of various conventional computer-readable media. In the context of this document, a "computer-readable medium" can be any medium or component that can contain, store, communicate, propagate, or transport instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, where an example of a computer is, for example, a computer program. Figure 1B 125 or other device), which can be any medium or component that can contain, store, and / or transmit instructions for use by or in connection with an instruction execution system, apparatus, or device (such as a computer). Computer-readable storage media do not include propagating signals and, therefore, can be considered non-transitory. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not a signal), not on the persistence of data storage (e.g., RAM, random access memory versus ROM, read-only memory).

[0215] If desired, the different functions discussed herein may be performed in different orders and / or simultaneously with one another. In addition, if desired, one or more of the above functions may be optional or may be combined.

[0216] Although various aspects of the invention are set out in the independent claims, further aspects of the invention comprise other combinations of features from the described embodiments and / or dependent claims with features of the independent claims, and not just the combinations explicitly set out in the claims.

[0217] It is also noted herein that although the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. On the contrary, several variations and modifications are possible without departing from the scope of the invention as defined in the appended claims.

[0218] The following abbreviations may be found in the specification and / or drawings and are defined as follows:

[0219] 5G fifth generation

[0220] AMF Access and Mobility Management Function

[0221] BBU Baseband Unit

[0222] BPSK Binary Phase Shift Keying

[0223] BW Bandwidth

[0224] CE Control Elements

[0225] CM cubic metric

[0226] CP Cyclic Prefix

[0227] CP-OFDM Cyclic Prefix OFDM

[0228] CU Central Unit

[0229] DCI Downlink Control Information

[0230] DCI format 0_1 ​​UL grant configurable by RRC

[0231] DFT Discrete Fourier Transform

[0232] DFT-s-OFDM Discrete Fourier Transform Extended OFDM

[0233] DMRS Demodulation Reference Signal

[0234] DU Distributed Unit

[0235] eNB (or eNodeB) Evolved Node B (e.g., LTE base station)

[0236] EPRE EPRE energy per resource element

[0237] FDRA Frequency Domain Resource Allocation

[0238] FDSS Frequency Domain Spectral Shaping

[0239] FDSS-SE FDSS with spectrum extension

[0240] FFT Fast Fourier Transform

[0241] gNB (or GNodeB) is a base station used for 5G / NR

[0242] I / F interface

[0243] IFFT inverse FFT

[0244] LTE Long Term Evolution

[0245] MAC Media Access Control

[0246] MCS modulation and coding scheme

[0247] MME Mobility Management Entity

[0248] MPR Maximum Power Reduction

[0249] ngMNG Next Generation

[0250] ng-eNBMNG-eNB Next Generation eNB

[0251] NR New Radio

[0252] N / W or NW network

[0253] OFDM Orthogonal Frequency Division Multiplexing

[0254] PAPR Peak to Average Power Ratio

[0255] PDU Protocol Data Unit

[0256] PHR Power Headroom Report

[0257] PRB Physical Resource Block

[0258] QPSK Quadrature Phase Shift Keying

[0259] RAN Radio Access Network

[0260] RB Resource Block

[0261] Rel Release

[0262] RE resource element

[0263] RLC Radio Link Control

[0264] RRH Remote Radio Head

[0265] RRC Radio Resource Control

[0266] RU Radio Unit

[0267] Rx Receiver

[0268] SE Spectrum Extension

[0269] SGW Service Gateway

[0270] SMF session management functions

[0271] Tx Transmitter

[0272] UE User Equipment (e.g., wireless, typically mobile)

[0273] UI User Interface

[0274] UL Uplink (from UE to network)

[0275] UPF user plane function

[0276] WI Work Item

[0277] w / wo have or do not have

Claims

1. A method comprising: Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; as well as A reference signal is transmitted or received by the node using the non-uniform reference signal configuration. 2 . The method according to claim 1 , wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band. 3 . The method according to claim 1 , wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation. The method according to claim 1 , wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

5. The method according to claim 4, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of the inner frequency band of the allocated frequency band, or a sparser reference signal distribution at the outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at the outer frequency band. 6 . The method of claim 5 , wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

7. The method of claim 6, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

8. The method according to any one of claims 1 to 3, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of a reference signal.

9. The method of claim 8, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

10. The method according to any of claims 8 or 9, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

11. The method according to claims 4 to 10, wherein the non-uniform reference signal configuration comprises a combination of a non-uniform RS pattern according to any one of claims 4 to 7 and a non-uniform power adaptation according to any one of claims 8 to 10.

12. The method according to any one of claims 1 to 11, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to the base station.

13. The method of any one of claims 1 to 11, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from a user equipment, and the base station confirms or configures the non-uniform reference signal configuration based in part on the received indication.

14. The method according to any one of claims 1 to 11, wherein the node performs transmitting the reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by a base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

15. The method according to any one of claims 1 to 11, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is used by the node to determine a reference signal position on the received signal, or to adjust a power of a reference signal learned from the non-uniform reference signal configuration, or to determine a reference signal position on the received signal and to adjust a power of a reference signal learned from the non-uniform reference signal configuration.

16. The method according to any one of claims 1 to 11, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is taken into account in receiver estimation to derive at least a joint filter and channel estimate.

17. The method according to any one of claims 1 to 16, wherein the node is a user equipment, wherein the determination of a non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from a network.

18. A computer program comprising instructions for performing the method of any one of claims 1 to 17 when the computer program is run on a device.

19. The computer program of claim 18, wherein the computer program is a computer program product comprising a computer readable medium bearing instructions embodied therein for use with the apparatus.

20. The computer program according to claim 18, wherein the computer program is directly loadable into an internal memory of the device.

21. An apparatus comprising means for performing the following operations: Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; and A reference signal is transmitted or received by the node using the non-uniform reference signal configuration.

22. The apparatus of claim 21, wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band.

23. The apparatus according to any one of claims 21 or 22, wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation.

24. The apparatus according to any one of claims 21 to 23, wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

25. The apparatus according to claim 24, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of an inner frequency band of the allocated frequency band, or a sparser reference signal distribution at an outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at the outer frequency band.

26. The apparatus of claim 25, wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

27. The apparatus of claim 26, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

28. The apparatus according to any one of claims 21 to 23, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of a reference signal.

29. The apparatus of claim 28, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

30. The apparatus according to any one of claims 28 to 29, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

31. The apparatus according to any one of claims 24 to 30, wherein the non-uniform reference signal configuration comprises a combination of a non-uniform RS pattern according to any one of claims 4 to 7 and a non-uniform power adaptation according to any one of claims 8 to 10.

32. The apparatus according to any one of claims 21 to 31, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to a base station.

33. An apparatus according to any one of claims 21 to 31, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from a user equipment, and the base station confirms or configures the non-uniform reference signal configuration in part based on the received indication.

34. An apparatus according to any one of claims 21 to 31, wherein the node performs transmitting the reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by a base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

35. An apparatus according to any one of claims 21 to 31, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is used by the node to determine the reference signal position on the received signal, or adjust the power of the reference signal learned from the non-uniform reference signal configuration, or determine the reference signal position on the received signal and adjust the power of the reference signal learned from the non-uniform reference signal configuration.

36. The apparatus according to any one of claims 21 to 31, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is considered in receiver estimation to derive at least a joint filter and channel estimate.

37. The apparatus according to any one of claims 21 to 36, wherein the node is a user equipment, wherein the determination of a non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from a network.

38. The device of any preceding device claim, wherein the component comprises: at least one processor; as well as At least one memory storing instructions that, when executed by at least one processor, cause said execution of said apparatus.

39. An apparatus comprising: one or more processors; as well as one or more memories storing instructions that, when executed by the one or more processors, cause the apparatus to at least: Determining, by the node, a non-uniform reference signal configuration within the allocated frequency band or within different frequency band segments of a total allocation for the entire allocated frequency band based on a filter power distribution for frequency domain spectrum shaping; as well as A reference signal is transmitted or received by the node using the non-uniform reference signal configuration.

40. The apparatus of claim 39, wherein the non-uniform reference signal configuration covers at least a portion of the entire allocated frequency band.

41. The apparatus of any one of claims 39 or 40, wherein the entire allocated frequency band comprises one of: an in-band allocation, or an in-band allocation and an excess frequency band allocation.

42. The apparatus according to any one of claims 39 to 41, wherein the non-uniform reference signal configuration comprises one or more non-uniform reference signal patterns.

43. An apparatus according to claim 42, wherein the one or more non-uniform reference signal patterns have a denser reference signal distribution in the middle of the inner frequency band of the allocated frequency band, or a sparser reference signal distribution at the outer frequency band of the entire allocated frequency band, or a denser reference signal distribution in the middle of the inner frequency band and a sparser reference signal distribution at the outer frequency band.

44. The apparatus of claim 43, wherein the denser reference signal distribution in the middle of the inner frequency band comprises at least one contiguous demodulation reference signal block.

45. The apparatus of claim 44, wherein the sparser reference signal distribution at the outer frequency band comprises smaller reference signal blocks relative to reference signal blocks used closer to the middle of the inner frequency band.

46. ​​The apparatus according to any one of claims 39 to 41, wherein the non-uniform reference signal configuration comprises non-uniform power adaptation of a reference signal.

47. The apparatus of claim 46, wherein power adaptation is used only for reference signals in the resource elements and not for data in the resource elements, or for both reference signals in the resource elements and data in the resource elements.

48. The apparatus according to any one of claims 46 to 47, wherein power adaptation is applied for at least one frequency band segment in the total allocation.

49. The apparatus according to any one of claims 42 to 48, wherein the non-uniform reference signal configuration comprises a combination of a non-uniform RS pattern from any one of claims 4 to 7 and a non-uniform power adaptation according to any one of claims 8 to 10.

50. The apparatus according to any one of claims 39 to 49, wherein the node is a user equipment, and the user equipment sends its capabilities in signaling and indicates its preferred demodulation reference signal configuration to a base station.

51. An apparatus according to any one of claims 39 to 49, wherein the node is a base station, and the base station receives an indication of a preferred demodulation reference signal configuration from a user equipment, and the base station confirms or configures the non-uniform reference signal configuration in part based on the received indication.

52. An apparatus according to any one of claims 39 to 49, wherein the node performs transmitting the reference signal, wherein an indication of the non-uniform reference signal configuration is transmitted by a base station, and wherein the non-uniform reference signal configuration is used for transmitting at least one subsequent signal by the node.

53. An apparatus according to any one of claims 39 to 49, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is used by the node to determine the reference signal position on the received signal, or adjust the power of the reference signal learned from the non-uniform reference signal configuration, or determine the reference signal position on the received signal and adjust the power of the reference signal learned from the non-uniform reference signal configuration.

54. The apparatus of any one of claims 39 to 49, wherein the node performs receiving the reference signal, wherein the non-uniform reference signal configuration is considered in receiver estimation to derive at least a joint filter and channel estimate.

55. The apparatus according to any one of claims 39 to 54, wherein the node is a user equipment, wherein the determination of a non-uniform reference signal configuration by the user equipment is performed based on an explicit or implicit indication from a network.

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