Waveform switching in data transmissions

Abstract

Embodiments of the invention relate to first communication device (100) and a second communication device (300) for waveform switching for data transmissions. Therefore, the first communication device (100) transmits a first control message (510) to the second communication device (300). The first control message (510) indicates at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission (540). The first communication device (100) thereafter receives a second control message (520) from the second communication device (300), and the second control message (520) indicates at least one of a first modulation order and a first number of resources for the data transmission (540). The first communication device (100) uses a first waveform associated with at least one of the first modulation order and the first number of resources for performing the data transmission (540) to the second communication device (300). Furthermore, embodiments of the invention also relate to corresponding methods and a computer program.

Description

[0001] WAVEFORM SWITCHING IN DATA TRANSMISSIONS

[0002] TECHNICAL FIELD

[0003] Embodiments of the invention relate to a first communication device and a second communication device for waveform switching in data transmissions. Furthermore, embodiments of the invention also relate to corresponding methods and a computer program.

[0004] BACKGROUND

[0005] Cyclic prefix (CP)-Orthogonal Frequency Division Multiplexing (OFDM) waveform suffers from high peak-to-average power ratio (PAPR). Because of high PAPR, the power amplifier (PA) needs to be operated with a back-off such that the peak signal of the transmitted OFDM signal also falls in the linear region of the PA. By reducing the PAPR, the efficiency of the PA is increased since the PA can be operated with a smaller back-off value.

[0006] Various methods such as clipping and filtering, tone reservation, active constellation extension, selective mapping etc. have been studied for OFDM PAPR reduction. Each of these methods have their own drawbacks, as some of them result in increased error vector magnitude of the modulated symbols, increased out-of-band (OOB) emissions, loss of spectral efficiency and need for transmitting additional side information to the receiver. Discrete Fourier Transform -Spread (DFT-S) OFDM is sometimes used in wireless systems owing to the assumption that it has low PAPR compared to CP-OFDM.

[0007] SUMMARY

[0008] An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.

[0009] Another objective of embodiments of the invention is to provide a waveform switching solution in data transmissions for reduced energy consumption.

[0010] The above and further objectives are solved by the subject matter of the independent claims.

[0011] Further embodiments of the invention can be found in the dependent claims.

[0012] According to a first aspect of the invention, the above mentioned and other objectives are achieved with a first communication device configured to: transmit a first control message to a second communication device, the first control message indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission; receive a second control message from the second communication device, the second control message indicating at least one of a first modulation order and a first number of resources for the data transmission; and perform the data transmission to the second communication device using a first waveform associated with at least one of the first modulation order and the first number of resources.

[0013] The at least one association between the waveform and at least one of the modulation order and the number of resources implies that there is one or more associations between the waveform and the modulation order and / or the number of resources for the data transmission.

[0014] The at least one of the modulation order and the number of resources are modulation order and number of resources to be scheduled by the second communication device for the coming data transmission. An advantage of the first communication device according to the first aspect is that by informing about the association between the waveform and the at least one of the modulation order and / or the number of resources, the first communication device can use a power efficient waveform for data transmission to the second communication device. This can result in energy saving at the first communication device. A further advantage is that the first communication device can itself determine the waveform for data transmission to the second communication device, without explicit indication from the second communication device.

[0015] In an implementation form of a first communication device according to the first aspect, the first communication device is configured to: transmit the first control message during a connection setup procedure, or as a response to a capability enquiry request received from the second communication device.

[0016] An advantage with this implementation form is that the first control message is transmitted once to the second communication device thereby avoiding the need for dynamic signaling resulting in saving of channel resources.

[0017] In an implementation form of a first communication device according to the first aspect, the first control message is a physical layer message, or a medium access control, MAC, control element, CE, message, or a radio resource control, RRC, message.

[0018] An advantage with this implementation form is that the first control message can be transmitted to the second communication device with different latency options and flexibility due to the different message types.

[0019] In an implementation form of a first communication device according to the first aspect, the first communication device is configured to: transmit the first control message to the second communication device upon reception of a third control message from the second communication device, the third control message indicating a request for the first control message.

[0020] An advantage with this implementation form is that the first communication device knows when to transmit the first control message rather than transmitting the first control message blindly without request. Also, the second communication device can trigger the transmission of the first control message thereby controlling the signaling procedure.

[0021] In an implementation form of a first communication device according to the first aspect, the third control message is a physical layer message, or a MAC CE message, or an RRC message.

[0022] In an implementation form of a first communication device according to the first aspect, the first communication device is configured to: determine the first waveform based on at least one of the first modulation order and the first number of resources.

[0023] The first waveform is associated with at least one of the first modulation order and the first number of resources.

[0024] An advantage with this implementation form is that the first communication device can determine the waveform for the data transmission to the second communication device, without explicit indication from the second communication device. This can result in reducing control information signaling.

[0025] In an implementation form of a first communication device according to the first aspect, the second control message further indicates the first waveform to be used for the data transmission. An advantage with this implementation form is that a power efficient waveform can be scheduled by the second communication device for the data transmission from the first communication device and thus resulting in energy savings at the first communication device.

[0026] In an implementation form of a first communication device according to the first aspect, the second control message is a downlink control information, DCI, message, or a MAC-CE message, or an RRC message.

[0027] In an implementation form of a first communication device according to the first aspect, the first waveform is any of: a CP- OFDM, a DFTS-OFDM, a UFMC, a FBMC, an OTFS, or a f-OFDM waveform.

[0028] An advantage with this implementation form is that the first communication device can support multiple waveforms and chose the best waveform at any given time from energy efficiency perspective, resulting in energy savings at the first communication device.

[0029] In an implementation form of a first communication device according to the first aspect, the number of resources is a number of resource blocks.

[0030] An advantage with this implementation form is that this reduces the amount of signaling needed for the first control message saving the control channel resources.

[0031] According to a second aspect of the invention, the above mentioned and other objectives are achieved with a second communication device configured to: receive a first control message from a first communication device, the first control message indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission; transmit a second control message to the first communication device, the second control message indicating at least one of a first modulation order and a first number of resources for the data transmission; and receive the data transmission from the first communication device in a first waveform determined based on the first control message and at least one of the first modulation order and the first number of resources.

[0032] An advantage of the second communication device according to the second aspect is that by informing about the association between the waveform and the at least one of the modulation order and / or the number of resources, the first communication device can use a power efficient waveform for data transmission to the second communication device. This can result in energy saving at the first communication device. A further advantage is that the first communication device can itself determine the waveform for data transmission to the second communication device, without explicit indication from the second communication device.

[0033] In an implementation form of a second communication device according to the second aspect, the second control message further indicates the first waveform.

[0034] An advantage with this implementation form is that a power efficient waveform can be scheduled by the second communication device for the data transmission from the first communication device and thus resulting in energy savings at the first communication device. In an implementation form of a second communication device according to the second aspect, the first control message is a physical layer message, or a MAC CE message, or an RRC message.

[0035] An advantage with this implementation form is that the first control message can be transmitted to the second communication device with different latency options and flexibility due to the different message types.

[0036] In an implementation form of a second communication device according to the second aspect, the second control message is a DCI message, or a MAC-CE message, or an RRC message.

[0037] In an implementation form of a second communication device according to the second aspect, the second communication device is configured to: transmit a third control message to the first communication device prior to receiving the first control message, the third control message indicating a request for the first control message.

[0038] An advantage with this implementation form is that the first communication device knows when to transmit the first control message rather than transmitting the first control message blindly without request. Also, the second communication device can trigger the transmission of the first control message thereby controlling the signaling procedure.

[0039] In an implementation form of a second communication device according to the second aspect, the third control message is a physical layer message, or a MAC CE message, or an RRC message.

[0040] In an implementation form of a second communication device according to the second aspect, the first waveform is any of: a CP-OFDM, a DFTS-OFDM, a UFMC, a FBMC, an OTFS, or a f-OFDM waveform.

[0041] An advantage with this implementation form is that the first communication device can support multiple waveforms and chose the best waveform at any given time from energy efficiency perspective, resulting in energy savings at the first communication device.

[0042] In an implementation form of a second communication device according to the second aspect, the number of resources is a number of resource blocks.

[0043] An advantage with this implementation form is that this reduces the amount of signaling needed for the first control message saving the control channel resources.

[0044] According to a third aspect of the invention, the above mentioned and other objectives are achieved with a method for a first communication device, the method comprises: transmitting a first control message to a second communication device, the first control message indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission; receiving a second control message from the second communication device, the second control message indicating at least one of a first modulation order and a first number of resources for the data transmission; and performing the data transmission to the second communication device using a first waveform associated with at least one of the first modulation order and the first number of resources. The method according to the third aspect can be extended into implementation forms corresponding to the implementation forms of the first communication device according to the first aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the first communication device.

[0045] The advantages of the methods according to the third aspect are the same as those for the corresponding implementation forms of the first communication device according to the first aspect.

[0046] According to a fourth aspect of the invention, the above mentioned and other objectives are achieved with a method for a second communication device, the method comprises: receiving a first control message from a first communication device, the first control message indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission; transmitting a second control message to the first communication device, the second control message indicating at least one of a first modulation order and a first number of resources for the data transmission; and receiving the data transmission from the first communication device in a first waveform determined based on the first control message and at least one of the first modulation order and the first number of resources.

[0047] The method according to the fourth aspect can be extended into implementation forms corresponding to the implementation forms of the second communication device according to the second aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the second communication device.

[0048] The advantages of the methods according to the fourth aspect are the same as those for the corresponding implementation forms of the second communication device according to the second aspect.

[0049] Embodiments of the invention also relate to a computer program, characterized in program code, which when run by at least one processor causes the at least one processor to execute any method according to embodiments of the invention. Further, embodiments of the invention also relate to a computer program product comprising a computer readable medium and the mentioned computer program, wherein the computer program is included in the computer readable medium, and may comprises one or more from the group of: read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), flash memory, electrically erasable PROM (EEPROM), hard disk drive, etc.

[0050] Further applications and advantages of embodiments of the invention will be apparent from the following detailed description.

[0051] BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The appended drawings are intended to clarify and explain different embodiments of the invention, in which:

[0053] - Fig. 1 shows a first communication device according to an embodiment of the invention;

[0054] - Fig. 2 shows a flow chart of a method for a first communication device according to an embodiment of the invention;

[0055] - Fig. 3 shows a second communication device according to an embodiment of the invention;

[0056] - Fig. 4 shows a flow chart of a method for a second communication device according to an embodiment of the invention;

[0057] - Fig. 5 shows a communication system according to an embodiment of the invention;

[0058] - Fig. 6 and 7 show simulation results; and

[0059] - Fig. 8 shows a signaling diagram according to further embodiments of the invention. DETAILED DESCRIPTION

[0060] In 3GPP 5G NR, a new waveform called DFTS-OFDM, also known as transform precoding, is used to overcome the PAPR problem of the CP-OFDM waveform. The typical assumption is that DFTS-OFDM waveform is beneficial for uplink (UL) coverage limited scenario because of its lower PAPR and cubic metric (CM) compared to CP-OFDM.

[0061] In 5G NR, the waveform to be used by the user equipment (UE) for UL transmission is configured by the gNB. Prior to release- 18, the waveform selection choice is configured by radio resource control (RRC) configuration for both dynamic and configured grant transmissions from the UE in the UL . In release- 18, for dynamic grant-based transmission, waveform choice is indicated to the UE using a field in the downlink control information (DCI) in a dynamic manner.

[0062] In the current 3GPP systems, the gNB determines which waveform to be scheduled for a certain UE e.g., depending on scheduling algorithm, complexity to dynamically switch the receiver operation to handle multiple waveforms, number of UEs to be scheduled in a slot, whether any UE needs to be scheduled with rank greater than 1, whether a UE needs to scheduled using multi-user MIMO, etc. However, this might not always be beneficial from the UE energy efficiency perspective. Sometimes, it is favorable for the UE to use a waveform with low PAPR in the UL as it is more power efficient and results in lower power consumption. The waveform switching is typically based on the assumption that DFTS-OFDM waveform has better PAPR compared to CP-OFDM. As is shown in the following disclosure, this is not always the case.

[0063] Traditionally, it is assumed that CP-OFDM waveform has worse PAPR and cubic metric performance compared to DFTS- OFDM waveform. However, when PAPR reduction techniques are applied to the CP-OFDM waveform, its PAPR and CM can be reduced. PAPR reduction methods like active constellation extension (ACE) do not require reserved subcarriers as in tone reservation methods and also does not require any side information exchange with the receiver. Methods based on ACE do not impact the bit-error-rate (BER) or out-of-band (OOB) emissions as well. It has been observed that when applying ACE-based PAPR reduction methods to both CP-OFDM and DFTS-OFDM, CP-OFDM PAPR and CM is sometimes better than the corresponding metrics of the DFTS-OFDM waveform.

[0064] Therefore, it is herein presented a first communication device and a second communication device for waveform switching in a data transmission in which an association between a waveform and modulation order and / or number of resources for the data transmission is employed for improved PA efficiency.

[0065] Fig. 1 shows a first communication device 100 according to an embodiment of the invention. In the embodiment shown in Fig. 1, the first communication device 100 comprises a processor 102, a transceiver 104 and a memory 106. The processor 102 is coupled to the transceiver 104 and the memory 106 by communication means 108 known in the art. The first communication device 100 may be configured for wireless and / or wired communications in a communication system. The wireless communication capability may be provided with an antenna or antenna array 110 coupled to the transceiver 104, while the wired communication capability may be provided with a wired communication interface 112 e.g., coupled to the transceiver 104.

[0066] The processor 102 may be referred to as one or more general-purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application-specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, or one or more chipsets. The memory 106 may be a read-only memory, a random access memory (RAM), or a non-volatile RAM (NVRAM). The transceiver 104 may be a transceiver circuit, a power controller, or an interface providing capability to communicate with other communication modules or communication devices, such as network nodes and network servers. The transceiver 104, memory 106 and / or processor 102 may be implemented in separate chipsets or may be implemented in a common chipset. That the first communication device 100 is configured to perform certain actions can in this disclosure be understood to mean that the first communication device 100 comprises suitable means, such as e.g., the processor 102 and the transceiver 104, configured to perform the actions.

[0067] According to embodiments of the invention the first communication device 100 is configured to: transmit a first control message 510 to a second communication device 300, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: receive a second control message 520 from the second communication device 300, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and perform the data transmission 540 to the second communication device 300 using a first waveform associated with at least one of the first modulation order and the first number of resources.

[0068] Furthermore, in an embodiment of the invention, the first communication device 100 for a communication system 500 comprises a transceiver configured to: transmit a first control message 510 to a second communication device 300, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: receive a second control message 520 from the second communication device 300, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and perform the data transmission 540 to the second communication device 300 using a first waveform associated with at least one of the first modulation order and the first number of resources.

[0069] Moreover, in yet another embodiment of the invention, the first communication device 100 for a communication system 500 comprises a processor and a memory having computer readable instructions stored thereon which, when executed by the processor, cause the processor to: transmit a first control message 510 to a second communication device 300, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: receive a second control message 520 from the second communication device 300, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and perform the data transmission 540 to the second communication device 300 using a first waveform associated with at least one of the first modulation order and the first number of resources.

[0070] Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a first communication device 100, such as the one shown in Fig . 1. The method 200 comprises: transmitting 202 a first control message 510 to a second communication device 300, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: receiving 204 a second control message 520 from the second communication device 300, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and performing 206 the data transmission 540 to the second communication device 300 using a first waveform associated with at least one of the first modulation order and the first number of resources

[0071] Fig. 3 shows a second communication device 300 according to an embodiment of the invention. In the embodiment shown in Fig. 3, the second communication device 300 comprises a processor 302, a transceiver 304 and a memory 306. The processor 302 is coupled to the transceiver 304 and the memory 306 by communication means 308 known in the art. The second communication device 300 may be configured for wireless and / or wired communications in a communication system. The wireless communication capability may be provided with an antenna or antenna array 310 coupled to the transceiver 304, while the wired communication capability may be provided with a wired communication interface 312 e.g., coupled to the transceiver 304. The processor 302 may be referred to as one or more general-purpose CPUs, one or more DSPs, one or more ASICs, one or more FPGAs, one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, one or more chipsets. The memory 306 may be a read-only memory, a RAM, or a NVRAM. The transceiver 304 may be a transceiver circuit, a power controller, or an interface providing capability to communicate with other communication modules or communication devices. The transceiver 304, the memory 306 and / or the processor 302 may be implemented in separate chipsets or may be implemented in a common chipset. That the second communication device 300 is configured to perform certain actions can in this disclosure be understood to mean that the second communication device 300 comprises suitable means, such as e.g., the processor 302 and the transceiver 304, configured to perform the actions.

[0072] According to embodiments of the invention the second communication device 300 is configured to: receive a first control message 510 from a first communication device 100, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: transmit a second control message 520 to the first communication device 100, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and receive the data transmission 540 from the first communication device 100 in a first waveform determined based on the first control message 510 and at least one of the first modulation order and the first number of resources.

[0073] Furthermore, in an embodiment of the invention, the second communication device 300 for a communication system 500 comprises a transceiver configured to: receive a first control message 510 from a first communication device 100, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: transmit a second control message 520 to the first communication device 100, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and receive the data transmission 540 from the first communication device 100 in a first waveform determined based on the first control message 510 and at least one of the first modulation order and the first number of resources.

[0074] Moreover, in yet another embodiment of the invention, the second communication device 300 for a communication system 500 comprises a processor and a memory having computer readable instructions stored thereon which, when executed by the processor, cause the processor to: receive a first control message 510 from a first communication device 100, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: transmit a second control message 520 to the first communication device 100, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and receive the data transmission 540 from the first communication device 100 in a first waveform determined based on the first control message 510 and at least one of the first modulation order and the first number of resources.

[0075] Fig. 4 shows a flow chart of a corresponding method 400 which may be executed in a second communication device 300, such as the one shown in Fig. 3. The method 400 comprises: receiving 402 a first control message 510 from a first communication device 100, the first control message 510 indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission 540: transmitting 404 a second control message 520 to the first communication device 100, the second control message 520 indicating at least one of a first modulation order and a first number of resources for the data transmission 540: and receiving 406 the data transmission 540 from the first communication device 100 in a first waveform determined based on the first control message 510 and at least one of the first modulation order and the first number of resources. Thus, the second communication device 300 receives the data transmission 540 in a first waveform which is determined based on the first control message 510 and at least one of the first modulation order and the first number of resources. This may be understood such that the second communication device 300 need not explicitly inform the first communication device 100 which waveform it should use for the data transmission 540. The first communication device 100 may chose the first waveform for the data transmission 540 based on the association between the waveform and at least one of the first modulation order and the first number of resources indicated in the second control message 520. The first communication device 100 then select the first waveform and performs the data transmission 540. The second communication device 300 needs to know which waveform the first communication device 100 uses for data transmission 540 to be able to decode the information contained the data transmission 540. For this, the second communication device 300 uses the at least one association between the waveform and at least one of the modulation order and the number of resources received in the first control message 510, and at least one of the first modulation order and the first number of resources scheduled for the data transmission 540 and indicated in the second control message 520.

[0076] Fig. 5 shows a communication system 500 according to an embodiment of the invention. The communication system 500 in the disclosed embodiment comprises a first communication device 100 and a second communication device 300 configured to communicate and operate in the communication system 500. For simplicity, the shown communication system 500 only comprises one first communication device 100 and one second communication device 300. However, the communication system 500 may comprise any number of first communication devices 100 and any number of second communication devices 300 without deviating from the scope of the invention.

[0077] In this particular example, the first communication device 100 is configured as a client device, such as a UE or any other suitable mobile device / terminal, while the second communication device 300 is configured as a network access node, such as a base station. The network access node may be part of a radio access network (RAN) and can include a communication interface for communication with a network (NW) such as a core network (CN). The communication between the first communication device 100 and the second communication device 300 may be performed by using channels in the DL and UL.

[0078] Further details related to embodiments of the invention will be described in a 3GPP context. Thus, 3GPP terminology, definitions, expressions and system architecture will be used. Especially, the first communication device 100 according to the invention may in these embodiments be configured to perform any of the described functions of a 3GPP UE. Correspondingly, the second communication device 300 according to the invention may in these embodiments be configured to perform any of the described functions of a 3GPP gNB. It may however be noted that embodiments of the invention are not limited thereto.

[0079] As aforementioned, the waveform switching is typically based on the assumption that DFTS-OFDM waveform has better PAPR compared to CP-OFDM. This is not always true.

[0080] Fig. 6 shows a performance comparison of CP-OFDM and DFTS-OFDM waveforms with and without ACE-based PAPR reduction methods for pi / 2-BPSK and QPSK modulations. As seen from Fig. 6, CP-OFDM with PAPR reduction has a loss compared to DFTS-OFDM with PAPR reduction for pi / 2-bpsk modulation, but for QPSK modulation CP-OFDM with PAPR reduction has a gain compared to DFTS-OFDM with PAPR reduction.

[0081] Fig. 7 shows a performance comparison of CP-OFDM and DFTS-OFDM waveforms with and without ACE-based PAPR reduction methods with 64-QAM modulation and different number of scheduled resource blocks (RBs). As seen from Fig. 7, CP-OFDM with PAPR reduction has a loss compared to DFTS-OFDM with PAPR reduction when the number of scheduled RBs is 5, whereas, for the case when the number of scheduled RBs is 12, CP-OFDM with PAPR reduction has a gain compared to DFTS-OFDM with PAPR reduction waveform.

[0082] From the above results, it is clear that when some receiver transparent PAPR reduction methods are used, it is not true that DFTS-OFDM has better PAPR than the CP-OFDM waveform. Further, PAPR and CM has a dependency on both the modulation order and the number of scheduled RBs. Based on this observation, a proposal for improving the PA efficiency is by providing association information for waveform selection of a data transmission.

[0083] Thus, it is herein disclosed a novel mechanism for waveform selection to be used in a coming data transmission which is a function of the number of scheduled resources and / or the modulation order for the data transmission. The novel mechanism involves the signaling of a first control message 510 indicating at least one association between a waveform and a modulation order and / or a number of resources for the data transmission. The information carried in the first control message 510 may be static information which is only conveyed once but is not limited thereto. Thus, the first control message 510 may also be dynamically signaled from the transmitter to the receiver.

[0084] The modulation order may be understood as the bits per symbol transmitted in a single channel use or the size of a symbol constellation from which the modulation symbols are chosen. For example, modulation order 1 may correspond to BPSK or pi / 2 BPSK constellation (i.e., 1 bit per modulated symbol) and modulation order 2 may correspond to QPSK constellation (i.e., 2 bits per modulated symbol). Alternatively, modulation order 2 may correspond to BPSK or pi / 2-BPSK constellation (i.e., 2 constellation points) and modulation order 4 may correspond to QPSK constellation (i.e., 4 constellation points). There might be other mappings of modulation order to constellations used for modulated data symbols.

[0085] The number of resources may be a number of resource blocks (RBs). A resource block in 3GPP 5G-NR specification is defined as 12 consecutive subcarriers in the frequency domain. However, other definitions of resource block may be used in the present solution of waveform switching.

[0086] An exemplary embodiment of the invention is illustrated by Table 1 below. Assume that a UE 100 supports two waveforms for UL data transmission, i.e., W1 and W2. The UE 100 has a receiver agnostic PAPR reduction method implemented which is unknown to the gNB 300. The UE 100 has knowledge about which waveform choice is better for UL data transmission depending on the modulation order and the number of scheduled RBs. The UE 100 hence indicates to the gNB 300 regarding the preferred waveform choice information for an UL data transmission. Here an UL data transmission may correspond to future data transmissions after sending the indication regarding the waveform choice from the UE 100 to the gNB 300. The indication regarding the waveform choice is a function of a modulation order and / or a number of scheduled RBs. This function or relationship is expressed as an association between a waveform and the modulation order and / or the number of scheduled RBs, and indicated in the first control message 510. The indication contains the information such that for any combination of modulation order and number resources to be scheduled by gNB 300 for UE 100, the preferred waveform choice for the UL data transmission is known.

[0087] In Table 1, if the number of scheduled RBs is less than an integer A (<A) and modulation order is 1 (pi / 2-BPSK or BPSK), the UE 100 prefers UL data transmission with waveform selection equal to W1.

[0088] Further, if the modulation order is 8, irrespective of the scheduled RBs, the UE 100 prefers UL transmission with waveform selection W2. These waveform selections are based on the association information that for the indicated waveform choice, better PAPR reduction and / or CM reduction can be achieved resulting in better PA efficiency of the UE 100. Further, the UE 100 prefers waveform W1 if for modulation order 1 and scheduled RBs is less than an integer A (<A) and also if the modulation order is 2 and scheduled RBs is less than an integer B (<B). So, for the same waveform choice Wl, there can be multiple associations of modulation order and number of RBs for scheduling.

[0089] The rules on how the information related to the association between a waveform and at least one of the modulation order and number of resources that is sent to the gNB 300 can be specified in a standard specification. For example, the granularity of the RBs or for which modulation orders the association information to be transmitted in the first control message 510 may be specified in a standard specification. Further, the information shown in Table 1 can be compressed and sent to the gNB 300 in a first control message 510. The compression rules maybe predefined. After transmission of the association information, the gNB 300 has complete knowledge of the preferred waveform choice for UE 100 for any combination of modulation order and number resources.

[0090] Table 1

[0091] After sending the association indication regarding the preferred waveform choice information to the gNB 300, the gNB 300 schedules an UL waveform for the UE 100 using the indicated association information. In this step, the gNB 300 may skip the explicit indication of the UL waveform to be used by the UE 100 in the DCI carrying the UL scheduling information. The UE 100, after receiving the DCI for UL scheduling can implicitly obtain the UL waveform to be used based on the modulation order and the number of scheduled RBs indicated in the DCI. The modulation order may be derived from a modulation and coding scheme (MCS) field in DCI associated with the UL scheduling. The number of scheduled RBs may be derived from frequency domain resource assignment information from the DCI associated with the UL scheduling.

[0092] Fig. 8 shows a signaling diagram illustrating further embodiments and aspects of the invention. As previously mentioned, the first control message 510 conveys the association between waveform and resources and / or modulation order. However, the transmission of the first control message 510 may be preceded by a request for such a control message by the gNB 300.

[0093] Thus, in I in Fig. 8, the gNB 300 transmits a third control message 530 to the UE. The third control message 530 indicates a request for the first control message 510. This indication of the request may be sent during a connection setup or as a part of capability enquiry request to the UE after connection is established. Alternatively, the request for first control message 510 may be sent separately in a new type of control message.

[0094] In embodiments of the invention, the third control message 530 is a physical layer message, or a MAC CE message or an RRC message. Thus, different types of signaling may be employed to send the third control message 530. If it is a part of connection setup or capability enquiry, it can be sent as an RRC message or a MAC CE message. If the third control message 530 is a new type of control message, it may be sent as a physical layer message.

[0095] In III in Fig. 8, the UE 100 in response to the reception of the third control message 530 transmits a first control message 510 to the gNB 300. The first control message 510, as previously mentioned, indicates at least one association between a waveform and at least one of a modulation order and a number of resources to be scheduled by the gNB 300 for a coming data transmission 540. Thus, the waveform may be associated with: the modulation order, the number of resources, or the modulation order and the number of resources.

[0096] The first control message 510 may be transmitted during a connection setup procedure, or as a response to a capability enquiry request received from the gNB 300. This means that the waveform association information in the first control message 510 may be sent to the gNB 300 even before any data transmission is performed from the UE 100.

[0097] In embodiments of the invention, the first control message 510 is a physical layer message, or a MAC CE message, or a RRC message.

[0098] The first control message 510 can be sent on a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH) or any other uplink channel that can carry information from the UE 100 to the gNB 300.

[0099] In IV in Fig. 8, the gNB 300 receives the first control message 510 from the UE 100. The gNB 300 demodulates and decodes the first control message 510 to derive the information conveyed therein.

[0100] The gNB 300 schedules at least one of a first modulation order and a first number of resources for the data transmission 540. This means that the gNB 300 schedules the first modulation order, the first number of resources, or the first modulation order and the first number of resources for the data transmission 540. The determination of the first modulation order and the first number resources for the data transmission 540 by the gNB 300 may depend on the amount of the data available at UE 100 and the scheduling algorithm and link adaptation algorithm implemented at the gNB 300. Based on the first control message 510 or more particularly on the indicated association and at least one of the first modulation order and the first number of resources, the gNB 300 determines a first waveform the UE 100 should use for the coming data transmission 540.

[0101] In V in Fig. 8, the gNB 300 transmits a second control message 520 to the UE 100. The second control message 520 indicates at least one of the first modulation order and the first number of resources for the data transmission 540 scheduled in step IV.

[0102] In embodiments of the invention, the second control message 520 is a DCI message, or a MAC-CE message, or an RRC message.

[0103] In VI in Fig. 8, the UE 100 receives the second control message 520 from the gNB 300. The UE 100 demodulates and decodes the second control message 520 to derive the information enclosed therein.

[0104] The waveform to be used for the coming data transmission 540 may be determined by the gNB 300. Therefore, in examples of the invention the modulation order and / or the number of resources indicated by the first control message 510 may be the same to the first modulation order and the first number of resources indicated by the second control message 520. In further examples of the invention, the first control message 510 may indicate a set of modulation order and / or a set of resources and the first modulation order and / or the first number of resources belongs to a subset of the set of modulation order and / or the set of resources indicated by the first control message 510. Such sets and subsets may be given by information disclosed in the exemplary Table 1 above.

[0105] In a first case, the UE 100 itself determines / derives the first waveform for the data transmission 540. Thus, in such cases the UE 100 determines the first waveform based on at least one of the first modulation order and the first number of resources indicated in the second control message 520. This means that the UE 100 may derive the first waveform based the first modulation order only, the first number of resources only, or the combination of the first modulation order and the first number of resources. The association between the first waveform and the modulation order and / or the first number of resources can be given by tables.

[0106] In a second case, it is the gNB 300 that determines the first waveform and signals the first waveform in the second control message 520 to the UE 100. In this case, the second control message 520 further indicates the first waveform to be used for the data transmission 540.

[0107] In VII in Fig. 8, the UE 100 performs the data transmission 540 to the gNB 300 using the first waveform associated with at least one of the first modulation order and the first number of resources. In the first case, where the gNB 300 did not explicitly indicate the first waveform in the second control message 520, to receive the data transmission 540, the gNB 300 needs to determine the first waveform based on the first control message 510 and at least one of the first modulation order and the first number of resources. This waveform determination step at the gNB 300 in the first case may be performed prior to transmitting the second control message 520 or before receiving the data transmission 540.

[0108] The first waveform may be any suitable waveform for the data transmission 540. In embodiments of the invention, the first waveform is any of: a CP-OFDM, a DFTS-OFDM, a UFMC, a FBMC, an OTFS, and an f-OFDM waveform.

[0109] In VIII in Fig. 8, the gNB 300 receives the data transmission 540 from the UE 100. The gNB 300 demodulates and decodes the data transmission 540 so as to derive the enclosed information. The data transmission 540 may be containing PUSCH data or PUCCH data or uplink sounding reference signal (SRS) transmission or a combination thereof.

[0110] It may further be noted that enquiry of UE capability may be performed between the UE 100 and the gNB 300 in a UE capability report procedure which is not shown in Fig. 8. The UE capability report procedure may involve receiving a capability enquiry message from gNB 300 to provide UE 100 capability information. Alternatively, the UE 100 itself may transmit the capability report without a request from the gNB 300.

[0111] A network access node herein may also be denoted as a radio network access node, an access network access node, an access point (AP), or a base station (BS), e.g., a radio base station (RBS), which in some networks may be referred to as transmitter, “gNB”, “gNodeB”, “eNB”, “eNodeB”, “NodeB” or “B node”, depending on the standard, technology and terminology used. The radio network access node may be of different classes or types such as e.g., macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby the cell size. The radio network access node may further be a station, which is any device that contains an IEEE 802.11-conformant media access control (MAC) and physical layer (PHY) interface to the wireless medium (WM). The radio network access node may be configured for communication in 3GPP related long term evolution (LTE), LTE-advanced, fifth generation (5G) wireless systems, such as new radio (NR) and their evolutions, as well as in IEEE related Wi-Fi, worldwide interoperability for microwave access (WiMAX) and their evolutions.

[0112] A client device herein may be denoted as a user device, a user equipment (UE), a mobile station, an internet of things (loT) device, a sensor device, a wireless terminal and / or a mobile terminal, or any communication apparatus (e.g. chip or chipset) that is configured to and / or is enabled to communicate wirelessly in a wireless communication system, sometimes also referred to as a cellular radio system. The UEs may further be referred to as mobile telephones, cellular telephones, computer tablets or laptops with wireless capability. The UEs in this context may be, for example, portable, pocket-storable, hand-held, computer- comprised, or vehicle-mounted mobile devices, enabled to communicate voice and / or data, via a radio access network (RAN), with another communication entity, such as another receiver or a server. The UE may further be a station, which is any device that contains an IEEE 802.11 -conformant MAC and PHY interface to the WM. The UE may be configured for communication in 3GPP related LEE, LTE-advanced, 5G wireless systems, such as NR, and their evolutions, as well as in IEEE related WiFi, WiMAX and their evolutions.

[0113] Furthermore, any method according to embodiments of the invention may be implemented in a computer program, having code means, which when run by processing means causes the processing means to execute the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may comprise essentially any memory, such as previously mentioned a ROM, a PROM, an EPROM, a flash memory, an EEPROM, or a hard disk drive.

[0114] Moreover, it should be realized that the first communication device 100 and the second communication device 300 comprise the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing or implementing embodiments of the invention. Examples of other such means, units, elements and functions are: processors, memory, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selecting units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, TCM encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the solution.

[0115] Therefore, the processors) of the first communication device 100 and the second communication device 300 may comprise, e.g., one or more instances of a CPU, a processing unit, a processing circuit, a processor, an ASIC, a microprocessor, or other processing logic that may interpret and execute instructions. The expression “processor” may thus represent a processing circuitry comprising aplurality of processing circuits, such as e.g., any, some or all of the ones mentioned above. The processing circuitry may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like.

[0116] Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

CLAIMS1. A first communication device (100) configured to: transmit a first control message (510) to a second communication device (300), the first control message (510) indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission (540); receive a second control message (520) from the second communication device (300), the second control message (520) indicating at least one of a first modulation order and a first number of resources for the data transmission (540); and perform the data transmission (540) to the second communication device (300) using a first waveform associated with at least one of the first modulation order and the first number of resources.

2. The first communication device (100) according to claim 1, configured to: transmit the first control message (510) during a connection setup procedure, or as a response to a capability enquiry request received from the second communication device (300).

3. The first communication device (100) according to claim 1 or 2, wherein the first control message (510) is a physical layer message, or a medium access control, MAC, control element, CE, message, or a radio resource control, RRC, message.

4. The first communication device (100) according to any one of the preceding claims, configured to: transmit the first control message (510) to the second communication device (300) upon reception of a third control message (530) from the second communication device (300), the third control message (530) indicating a request for the first control message (510).

5. The first communication device (100) according to claim 4, wherein the third control message (530) is a physical layer message, or a MAC CE message, or an RRC message.

6. The first communication device (100) according to any one of claims 1 to 5, configured to: determine the first waveform based on at least one of the first modulation order and the first number of resources.

7. The first communication device (100) according to any one of claims 1 to 5, wherein the second control message (520) further indicates the first waveform to be used for the data transmission (540).

8. The first communication device (100) according to claim 7, wherein the second control message (520) is a downlink control information, DCI, message, or a MAC-CE message, or an RRC message.

9. The first communication device (100) according to any one of the preceding claims, wherein the first waveform is any of: a CP-OFDM, a DFTS-OFDM, a UFMC, a FBMC, an OTFS, or an f-OFDM waveform.

10. The first communication device (100) according to any one of the preceding claims, wherein the number of resources is a number of resource blocks.

11. A second communication device (300) configured to: receive a first control message (510) from a first communication device (100), the first control message (510) indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission (540);transmit a second control message (520) to the first communication device (100), the second control message (520) indicating at least one of a first modulation order and a first number of resources for the data transmission (540); and receive the data transmission (540) from the first communication device (100) in a first waveform determined based on the first control message (510) and at least one of the first modulation order and the first number of resources.

12. The second communication device (300) according to claim 11 , wherein the second control message (520) further indicates the first waveform.

13. The second communication device (300) according to claim 11 or 12, wherein the first control message (510) is a physical layer message, or a MAC CE message, or an RRC message.

14. The second communication device (300) according to any one of claims 11 to 12, wherein the second control message (520) is a DCI message, or a MAC-CE message, or an RRC message.

15. The second communication device (300) according to any one of claims 11 to 14, configured to: transmit a third control message (530) to the first communication device (100) prior to receiving the first control message (510), the third control message (530) indicating a request for the first control message (510).

16. The second communication device (300) according to claim 15, wherein the third control message (530) is a physical layer message, or a MAC CE message, or an RRC message.

17. The second communication device (300) according to any one of claims 11 to 16, wherein the first waveform is any of: a CP-OFDM, a DFTS-OFDM, a UFMC, a FBMC, an OTFS, or an f-OFDM waveform.

18. The second communication device (300) according to any one of claims 11 to 17, wherein the number of resources is a number of resource blocks.

19. A method (200) for a first communication device (100), the method (200) comprising: transmitting (202) a first control message (510) to a second communication device (300), the first control message (510) indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission (540); receiving (204) a second control message (520) from the second communication device (300), the second control message (520) indicating at least one of a first modulation order and a first number of resources for the data transmission (540); and performing (206) the data transmission (540) to the second communication device (300) using a first waveform associated with at least one of the first modulation order and the first number of resources.

20. A method (400) for a first communication device (300), the method (400) comprising: receiving (402) a first control message (510) from a first communication device (100), the first control message (510) indicating at least one association between a waveform and at least one of a modulation order and a number of resources for a data transmission (540); transmitting (404) a second control message (520) to the first communication device (100), the second control message (520) indicating at least one of a first modulation order and a first number of resources for the data transmission (540); and receiving (406) the data transmission (540) from the first communication device (100) in a first waveform determined based on the first control message (510) and at least one of the first modulation order and the first number of resources.

21. A computer program with a program code for performing a method according to claim 19 or 20 when the computer program runs on a computer.17

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