WO2016175689A1

WO2016175689A1 - Methods for transmitting data using a combination of single-carrier and multi-carrier waveforms

Info

Publication number: WO2016175689A1
Application number: PCT/SE2015/050479
Authority: WO
Inventors: Miguel Lopez; Bo Hagerman; Dennis SUNDMAN
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2015-04-29
Filing date: 2015-04-29
Publication date: 2016-11-03

Abstract

Embodiments herein relate to a method performed by a transmitting device (12) for transmitting data payload in a protocol data unit to a receiving device (10) in a wireless communication network (1), wherein the protocol data unit comprises a preamble modulated into a multicarrier waveform and the data payload. The transmitting device (12) modulates a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform. The transmitting device (12) further transmits the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data payload of the single-carrier waveform to the receiving device (10).

Description

Methods for transmitting data using a combination of single-carrier and

multi-carrier waveforms

5 TECHNICAL FIELD

Embodiments herein relate to a transmitting device, a receiving device and methods performed therein. In particular, embodiments herein relate to transmitting data payload in a protocol data unit to the receiving device in a wireless communication network.

1 0

BACKGROUND

In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations and/or user equipments (UEs), may communicate via an Access Network to one or more core networks. The access network

1 5 covers a geographical area served by a radio access node, e.g., a Wi-Fi access point, Wi- Fi access controller, a radio base station (RBS), which in some networks may also be called, for example, a "NodeB" or "eNodeB". The wireless communication network may use a number of different technologies, such as Wireless Local Access Network (WLAN), any 802.1 1 technique, any 802.15 technique e.g. Wreless Personal Access Network

20 (WPAN), just to mention a few possible implementations. In WLANs the radio access node may also be referred to as an access point, a wireless router, access controller, wireless access node, or an Access Point Station (AP STA) and the wireless devices may be referred to as Stations (STA) or non-Access Point Stations (non-AP STA).

In WLAN, data are transmitted over an air interface, a so called 802.11 ah air

25 interface, wherein Protocol Data Units (PDU), e.g. Physical Layer Convergence Protocol (PLCP) PDUs (PPDU), are communicated between the wireless devices and the radio access node.

802. 11ah Physical Layer and PPDU Format

30 The 802.1 1 ah standard introduces a sub 1 GHz, for S1 G, Physical Layer (PHY) specification. This PHY provides support for 1 MHz, 2MHz, 4MHz, 8MHz and 16 MHz channel bandwidths, and Orthogonal Frequency-Division Multiplexing (OFDM) with a sub- carrier spacing of 31.25 kHz may be used. In addition, three types of PPDUs are defined in the 802.1 1 ah standard: S1G_1 M PPDU for 1 MHz bandwidth.

SHORT PPDU for >= 2 MHz bandwidth.

LONG PPDU, also for >= 2 MHz bandwidth.

The LONG PPDUs provide functionality necessary to support Multi User - Multiple 5 Input Multiple Output (MU-MIMO), while the S1 G_1 M PPDUs and SHORT PPDUs only support Single User (SU)-MIMO.

The S1G_1 M PPDU format is illustrated in Figure 1 . The PHY header is encapsulated in a Signal (SIG) field of 6 OFDM symbols, which in turn is comprised in a preamble further comprising a Short Training Field (STF) and a Long Training Field (LTF) o each of 4 OFMD symbols, while a Medium Access Control (MAC) header is comprised in a data field, also referred to herein as data payload, of a variable number of OFDM symbols. The data field further comprises a Frame Body of a variable number of OFDM symbols, and a Frame check sequence. The SIG field may comprise an Aggregation bit that is set to one whenever the data is encapsulated in an aggregated MAC Protocol Data 5 Unit (MPDU). The aggregated MPDU may comprise a number of MPDU delimiters and MPDUs separated by a pad field. Each MPDU may comprise a MAC header, a Frame Body of a variable number of OFDM symbols, and a Frame check sequence. The PPDU format of an S1 G_1 M Aggregated-MPDU (A-MPDU) is shown in Figure 2.The data field, in both non-aggregated and aggregated MPDU, comprises a variable number of OFDM0 symbols. When the normal guard interval is used, each OFDM symbol, including its cyclic prefix (CP), is 40 us long, as shown in Figure 3. Each OFDM symbol comprises data sub- carriers and pilot sub-carriers. The numbers of data and pilot sub-carriers are dependent on the channel bandwidth. The number of data sub-carriers N_SD is 24, 52, 108, 234 and 468 for channel bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz and 16 MHz respectively. A5 detailed description of the PHY is given in Draft Standard IEEE P802.1 1ah™/D3.0.

802.1 1 ah Transmitter chain

Figure 4 depicts a block diagram of a transmitter chain for the data field, for single layer transmission. The transmitting device appends service field, tail bits, and pad bits to0 an input data bit stream. The data bit stream is scrambled in a scrambler and then channel encoded in a channel encoder. Bits of the channel encoded data bit stream are then grouped into a number of bits per symbol and fed to an interleaver. The interleaved groups of bits are mapped to constellation symbols and mapped to subcarriers in a symbol and subcarrier mapper. Pilots are then inserted. The symbols are then processed5 in an Inverse Fast Fourier Transform (IFFT) and a cyclic prefix is appended. The symbols are then fed to a pulse shaping filter and shaped into a multicarrier waveform and an upmixing and amplification are then provided to the multicarrier waveform before the multicarrier waveform is transmitted over an antenna. Figure 5 shows in detail the pilot insertion block, using 1 MHz channel bandwidth as an example. Groups of A/_SD

Quadrature amplitude modulation/Phase Shift Keying (QAM/PSK) constellation symbols are mapped to data subcarriers -13 to -1 and 1 to 13, and provided from the symbol and subcarrier mapper. The pilots are then inserted, e.g. at subcarriers -7 and 7.

Sensor STAs

The 802.1 1 ah amendment introduced a new sensor type STA. It is a new type of non-Access Point (AP) STA, using data frames with a small data payload size and expected to have low duty cycle and low traffic volumes. These STAs are typically battery driven and power efficiency is of the utmost importance.

One of the goals of 802.1 1 ah is to provide enhanced coverage compared to previous standards. This is achieved by a combination of reducing the carrier frequency to below 1 GHz, and by robust modulation and coding. However, the more robust

Modulation and Coding Schemes (MCS) result in longer packets because the code rate is low, e.g. as low as 1/4, the modulation order is low, e.g. Binary Phase Shift Keying (BPSK), and the overhead is significant. However, long packets are undesirable for sensor STAs because transmitting or receiving long packets drains the battery. Hence, extending the range is partly achieved at the expense of power efficiency, i.e. reduced battery lifetime.

The MCSs that stationary STAs, e.g. wireless temperature sensors, may successfully decode are, to a large extent, determined by a path loss from the Access Point (AP). The most robust MCS for S1G_1 M PPDU is MCS10, which is built from MCSO by adding a repetition code. Thus, MCS10 modulated packets are roughly twice as long as MCSO modulated packets, assuming both type of packets are carrying the same payload. Hence, STAs with large path loss will often use MCS10, and will have a battery life that is roughly ½ of the battery life of STAs that often use MCSO as long packets drain the battery. More generally, the least robust MCS that a wireless device, such as a sensor STA, can effectively use is directly coupled to the battery life and this leads to a reduced experienced performance of the wireless device. SUMMARY

An object of embodiments herein is to provide a mechanism to efficiently communicate within a wireless communication network to improve the performance of transmitting/receiving devices in the wireless communication network.

5

The object is achieved by providing a method performed by a transmitting device for transmitting data payload in a protocol data unit to a receiving device in a wireless communication network. The protocol data unit comprises a preamble modulated into a multicarrier waveform and the data payload. The transmitting device modulates a part or o all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform. The transmitting device transmits the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data payload of the single- carrier waveform to the receiving device.

The object is achieved by providing a method performed by a receiving device for 5 demodulating a waveform carrying data payload from a transmitting device in a wireless communication network. The receiving device receives a protocol data unit, from the transmitting device, which protocol data unit comprises a multicarrier modulated preamble with a multicarrier waveform and the data payload. A part or all of the data payload is single-carrier modulated with a single-carrier waveform. The receiving device determines0 whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit. The receiving device demodulates the multicarrier modulated preamble; and when being determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, demodulates the part or all of the data payload in the protocol data unit that is single-carrier modulated.

5 The object is achieved by providing a receiving device for demodulating a

waveform carrying data payload from a transmitting device in a wireless communication network. The receiving device being configured to receive a protocol data unit, from the transmitting device, which protocol data unit comprises a multicarrier modulated preamble with a multicarrier waveform and the data payload. A part or all of the data payload is0 single-carrier modulated with a single-carrier waveform. The receiving device is further configured to determine whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit. In addition, the receiving device is further configured to demodulate the multicarrier modulated preamble, and, when being determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, to demodulate the part or all of the data payload in the protocol data unit that is single-carrier modulated.

The object is achieved by providing a transmitting device for transmitting data payload in a protocol data unit to a receiving device in a wireless communication network. 5 The protocol data unit comprises a preamble modulated into a multicarrier waveform and the data payload. The transmitting device is configured to modulate a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single- carrier waveform. The transmitting device is further configured to transmit the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data o payload of the single-carrier waveform to the receiving device.

By performing single-carrier modulation on a part or all of the data payload the length of the data payload is shortened and as the preamble is multicarrier modulated legacy receiving devices are still able to read the preamble. The single-carrier modulation 5 requires no cyclic prefix and thus provides for transmissions with 75% the length of multi- carrier modulated transmissions, thus, embodiments reduce packet lengths, such that extended range of the communication does not lead to large reduction in battery life drained during transmitting/receiving the data payload. Using single-carrier modulation also increases transmitting (TX) power efficiency compared to multicarrier modulation,0 and single-carrier modulation also increases the link performance. Hence, using single- carrier modulation for a part or all of the data payload improves the performance of the transmitting device as well as the receiving device when communicating in the wireless communication network. 5 BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail in relation to the enclosed drawings, in which:

Figure 1 shows a protocol data unit;

Figure 2 shows a protocol data unit;

0 Figure 3 shows symbols with cyclic prefixes;

Figure 4 shows a flowchart depicting a process for OFDM modulating a data bit stream;

Figure 5 shows a process of inserting pilots into a group of data symbols; Figure 6a shows an overview depicting a wireless communication network5 according to embodiments herein; Figure 6b shows a flowchart of a transmitting device according to

embodiments herein;

Figure 7 shows a schematic overview of inserting one or more training

signals into a single-carrier waveform according to embodiments herein;

Figure 8 shows a schematic overview of inserting one or more training

signals into a single-carrier waveform according to embodiments herein;

Figure 9 shows a schematic overview of periods comprising data and

training signals according to embodiments herein;

Figure 10 shows a protocol data unit (PDU) modulated according to

embodiments herein;

Figure 11 shows a block diagram of a process for transmitting data payload according to embodiments herein;

Figure 12 shows a modulation PPDU format according to embodiments

herein;

Figure 13 shows a shows an embodiment depicting a process taking different conditions into account when determining whether to single-carrier modulate a part of all of the data payload;

Figure 14 shows a flowchart depicting a method at the receiving device

according to embodiments herein;

Figure 15 shows a flowchart depicting a method performed by a transmitting device according to embodiments herein;

Figure 16 shows a flowchart depicting a method performed by a receiving device according to embodiments herein;

Figure 17 shows a block diagram depicting a transmitting device according to embodiments herein; and

Figure 18 shows a block diagram depicting a receiving device according to embodiments herein.

DETAILED DESCRIPTION

Embodiments herein relate to wireless communication networks in general. Fig. 6a is a schematic overview depicting a wireless communication network 1 . The wireless communication network 1 comprises one or more access networks and one or more CNs. The wireless communication network 1 may use a number of different technologies, such as WiFi e.g. 802.11 or 802.15, Long Term Evolution (LTE), LTE- Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide

5 Interoperability for Microwave Access (WMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. The wireless communication network 1 is exemplified herein as a W-Fi network, also referred to as WLAN.

The wireless communication network 1 comprises a transmitting device 12. The transmitting device 12 may be a radio communication node such as an access point or o access controller, e.g. an AP STA, a NodeB, an evolved Node B (eNB, eNode B), a base transceiver station, Access Point Base Station, base station router, Wi-Fi access point, or any other network unit capable of communicating with a receiving device depending e.g. on the radio access technology and terminology used. The transmitting device 12 may also be a non-AP STA i.e. a wireless device or similar transmitting data payload to the 5 access point.

In the wireless communication network 1 , a receiving device 10 such as a radio communication device e.g. a non-AP STA, a mobile station, user equipment, STA, and/or wireless device, communicate via the access network. It should be understood by the skilled in the art that "wireless device" is a non-limiting term which means any terminal,0 wireless terminal, user equipment, Machine Type Communication (MTC) device, Sensor STA, Device to Device (D2D) terminal, or node e.g. Personal Digital Assistant (PDA), laptop, mobile phone, sensor, relay, mobile tablets or even a small base station receiving communication from the transmitting device 12. The receiving device 10 may further be an access point also called an AP-STA, an access controller, or similar.

5 According to embodiments herein the transmitting device 12 modulates a part or all of a data payload in a protocol data unit using a single-carrier modulation into a single- carrier waveform. The protocol data unit comprises a preamble modulated into a multicarrier waveform, and the transmitting device 12 transmits the protocol data unit with the preamble and the data payload to the receiving device 10. Single-carrier waveform0 and multicarrier waveform may also be referred to as single-carrier symbols and

multicarrier symbols.

Thus, the preamble is kept multicarrier modulated, but the data payload, or at least a part of the data payload, is modulated using a single-carrier modulation instead of a multicarrier modulation. Channel coding, symbol mapping and other physical layer

5 characteristics may be kept, but the IFFT and cyclic prefix are omitted at the transmitter side of the data payload or part of the payload, thus simplifying the complexity at the transmitting device 12.

The preamble and some of the data payload may be OFDM modulated, while the rest of the data payload is single-carrier modulated. By keeping the preamble modulated 5 with e.g. OFDM, a degree of compatibility with both the current 802.11 ah standard and receiver algorithms is achieved. One well known drawback of multicarrier modulation such as OFDM modulation is its large Peak to Average Power Ratio (PAPR). A large PAPR typically results in Transmitting (TX) power backoffs and mediocre TX power efficiency. These are undesirable traits, especially in transmitters aimed at providing extended o coverage. Hence, using single-carrier modulation results in an improved TX power efficiency in e.g. 802.11 ah transmitters. Furthermore, multicarrier modulation, together with non-capacity achieving convolutional codes, provides a suboptimal PHY link performance because it does not exploit the full multipath diversity present in some outdoor propagation environments. Hence, embodiments herein using the single carrier 5 modulation reduce packet lengths, increase TX power efficiency, and also increase the link performance in e.g. 802.11 ah sensor networks, such that extended range of the communication does not lead to large reduction in battery life drained during

transmitting/receiving the data payload. 0 Embodiments herein introduce a hybrid modulation packet format, also referred to as a mixed PPDU format or just PPDU format according to embodiments herein, comprising a multicarrier modulated preamble, e.g. an OFDM modulated preamble, followed by a single-carrier modulated, e.g. linearly single-carrier modulated, data payload or part of the data payload. PHY signaling may be used to indicate the single-carrier

5 modulated packet transmissions, making the hybrid modulation packet format backward compatible with existing systems. Some embodiments herein may be implemented in an 802.1 1 ah system.

Embodiments herein are especially useful for the narrower channel bandwidths, such as 1 MHz and 2 MHz, because at lower baud rates there is less inter-symbol

0 interference and near optimum single-carrier demodulators have lower complexity than for wider channels.

For example, in the case of the protocol data unit is a basic PPDU when an Aggregation field in the SIG field is set to 0, then the aggregation may be set to 'OFF'. The transmitting device 12 may utilize a transmitter chain for the preamble that is identical5 to a transmitter chain specified in the Draft Standard IEEE P802.11 ah™/D3.0. The transmitter chain of the transmitting device 12 for the data payload field or part of the data payload field is illustrated in Figure 6b.

Action 601. The transmitting device 12 may append service field, tail bits, and pad bits to a data bit stream or a data payload.

Action 602. The transmitting device 12 may scramble the bits of the data payload in a scrambler.

Action 603. The transmitting device 12 may channel encode the scrambled bits with a channel encoder.

Action 604. The transmitting device 12 may group the channel encoded bits into a number of bits per symbol.

Action 605. The transmitting device 12 may then interleave the groups of bits in an interleaver.

Action 606. The transmitting device 12 maps the interleaved groups of bits into symbols belonging to a symbol constellation in a symbol mapper. The symbol constellation, e.g. BPSK, is a set of symbols comprising constellation symbols.

Action 607. The transmitting device 12 may append a training sequence or signal to the data payload or part of data payload of the protocol data unit, wherein said training signal is known at both the transmitting device 12 and the receiving device 10.

Action 608. The transmitting device 12 may comprise a linear modulator. The single-carrier waveform may be obtained by means of the linear modulator. The linear modulator may comprise a constellation rotation unit, rotating one or more constellation symbols. Rotation of the constellation symbols, such as QAM/PSK constellation symbols, reduces the number of zero crossings and a PAPR reduction is a direct consequence of this.

Action 609. The transmitting device 12 may further pulse shape the rotated constellation symbols in a pulse shape filter into the single-carrier waveform.

Action 610. The transmitting device 12 may then perform upmixing and amplification the single-carrier waveform before transmitting the single-carrier modulated data over an antenna.

The prior art transmitter chain shown in Figure 4 differs in several ways from the proposed transmitter chain shown in Figure 6b:

Notice that a pilot insertion block, present in Figure 4, is removed in Figure 6b. In its place there is a new block, action 607, that appends one or more training signals to the data payload of the protocol data unit. The IFFT block, present in Figure 4, is excluded in Figure 6b. This means that the frequency domain modulation used in Figure 4 is replaced in Figure 6b by time domain modulation for the part or all of the data payload of the protocol data unit.

5 - The cyclic prefix insertion block, present in Figure 4, is removed in Figure

6b. The cyclic prefix is not necessary when single-carrier modulation is applied, and therefore the data payload in the single-carrier part of the protocol data unit introduces less overhead compared to the data payload in the prior art. - A new constellation symbol rotation block 608, not present in Figure 4, has 1 o been added in Figure 6b. The purpose of this block is to reduce the PAPR of the transmitted signal.

The rotated constellation symbol stream in the data payload part of the protocol data unit is filtered through a pulse shaping filter into the single-carrier waveform, shown in Figure 6b action 609, and then up-converted to the carrier 1 5 frequency, and amplified prior to transmission. Although it is convenient to use the same filter in the pulse shaping filters blocks in Figure 4 and in Figure 6b, it is not strictly necessary and different filters could be used.

The following is a detailed description of the transmit processing according to the

20 embodiments herein.

In action 607 above, to each group of A/_SD QAM/PSK constellation symbols there is a training sequence, also referred to herein as training signals, appended consisting of N_TR arbitrary PSK or QAM constellation symbols, as exemplified in Figure 7 for the case of 1 MHz channel bandwidth. A/_SD QAM/PSK constellation symbols may be symbols 1 to

25 24, and N_TR QAM/PSK constellation symbols may be symbols 1 to 8.

In general, the training sequence, N_TR training signals or symbols, may be inserted at the end of the data payload, A/_SD data symbols, as shown in Figure 8. Although it is feasible to insert the training signals at the beginning or interspersed in a comb pattern, it is recommended to insert them at the end for trellis termination. The value of N_TR is a

30 design parameter. Large values of N_TR allow improved channel tracking, but also result in large overhead. The following table lists recommended values that yield the same amount of overhead, excluding the cyclic prefix, as OFDM modulated packets. With these recommended values the duration of each group of A/_SD+A/_m symbols is 32 με, which is the duration of one Inverse Discrete Fourier Transform (IDFT) period in 802.11 ah, as

35 shown in Figure 9. Channel bandwidth (MHz) Number of training symbols N_XR

1 8

2 12

4 20

8 22

16 44

In action 608, a rotation is applied to the constellation symbols. The rotation angle is a design parameter, and it may depend on the symbol constellation. It is intended to reduce the PAPR of the signal. The following table lists some recommended values of a rotation angle that typically yield low PAPR.

The IFFT, or similar conversion from frequency domain to time domain, and cyclic prefix insertion actions present in the prior art transmitter, see Figure 4, are omitted.

The baud rate is equal to the sampling rate, as shown in the table below. The baud rate is the symbol rate or modulation rate in symbols per second or pulses per second. It is the number of distinct symbol changes or signaling events made to the transmission medium per second in a digitally modulated signal or a line code.

Channel bandwidth baud rate Symbol period (MHz) (Megabaud) (μ<

1 1 1

2 2 0.5 4 4 0.25

8 8 0.125

16 16 0.0625

In action 609, the pulse shaping filter may be chosen by the designers. The pulse shaping filter is not specified in 802.11 ah. In one example of pulse shaping filter, the common root raised cosine pulse is chosen, suitably windowed, e.g. Hann window, to 5 ensure that the transmission mask in Section 24.3.16 of 802.1 1 ah D3.0 is fulfilled. Note that the pulse shaping filter does not need to be the same in the different parts of the PDU, although using the same pulse shaping filter throughout the whole PDU is preferred.

Figure 10 discloses a protocol data unit according to embodiments herein. The o protocol data unit comprises a part with multicarrier modulation, e.g. STF of 4 OFDM symbols, LTF of 4 OFDM symbols and SIG of 6 OFDM symbols. The protocol data unit further comprises a second part of time domain modulation comprising data or data payload that is single-carrier modulated.

Embodiments herein have different embodiments depending on whether the

5 Aggregation bit in the SIG field is set to 0 or 1. The description above corresponds to the case of Aggregation OFF, i.e. aggregation bit = 0. The difference between the two cases is that when no aggregation is used, all the data payload is single-carrier modulated, while in the case where aggregation is used, some or all of the data payload is single-carrier modulated. A block diagram of the transmitting device 12 process for transmitting data0 payload taking also aggregation into account is depicted in Figure 11. The multicarrier modulation is exemplified in Figure 11 using the OFDM modulation.

Action 1101. The transmitting device 12 may append service field, tail bits, and pad bits to a data bit stream or a data payload.

Action 1102. The transmitting device 12 may scramble the bits in a scrambler.5 Action 1103. The transmitting device 12 may channel encode the scrambled bits in a channel encoder.

Action 1104. The transmitting device 12 may group the channel encoded bits into a number of bits per symbol.

Action 1105. The transmitting device 12 may interleave the groups of bits in an0 interleaver. Action 1106. The transmitting device 12 maps the interleaved groups of bits into symbols belonging to a symbol constellation in a symbol mapper or a symbol and subcarrier mapper depending whether single-carrier modulation or multicarrier modulation is performed.

Action 1107. The transmitting device 12 may determine whether a part of the data payload is to be OFDM modulated or not, see conditions in e.g. Figure 13. For example, a part of an aggregated MPDU may be determined to be OFDM modulated.

Action 1108. When the part of the data payload is to be OFDM modulated the transmitting device 12 may insert pilot/pilots to the part of data payload.

Action 1109. The transmitting device 12 may then process constellation symbols together with the pilot/pilots via an IFFT process or similar to produce OFDM symbols.

Action 1110. The transmitting device 12 may further append a cyclic prefix to the OFDM symbols.

Action 1111 . When a part or all of the data payload is not to be OFDM modulated, i.e. the part or all data payload is to be single-carrier modulated, the transmitting device 12 may append a training sequence or one or more training signals into the part or all data payload.

Action 1112. The transmitting device 12 may rotate the constellation symbols of the data payload.

Action 1113. The transmitting device 12 may further pulse shape the rotated constellation symbols into the single-carrier waveform, and/or the multicarrier OFDM symbols into the multicarrier waveform of the data payload in a respective pulse shaping filter or a same pulse shaping filter.

Action 1114. The transmitting device 12 may then perform upmixing and amplification of the single-carrier waveform or the multicarrier waveform before

transmitting the single-carrier modulated data payload and/or the multicarrier modulated data payload over an antenna.

A modulation PPDU format according to embodiments herein is exemplified in Figure 12. The preamble may be OFDM modulated and the data payload e.g. aggregated MPDU, may be both OFDM modulated and single-carrier modulated, also called time domain modulated.

In some embodiments the transmitting node 12 signals the use of the modulation according to embodiments herein to the protocol data unit to the receiving node 10. The PHY header in the S1G_1 M, SHORT and LONG PPDUs may comprise a 4 bit MCS field which is used to signal the MCS to the receiver. Currently there are 10 MCSs defined in the 802.11 ah specification. Therefore, 6 new MCSs can be defined. Thus, up to 6 new MCSs using the modulation PPDU format according to embodiments herein can be

5 defined and be signaled. For example a modulation PPDU format using the same channel coding as MCSO but the PPDU modulation format described herein may be named MCS11 and signaled using an unused value of the MCS field.

In another embodiment, the modulation PPDU format according to embodiments may be signaled using a spare reserved bit in the PHY header. For example bit 0 in the o SHORT PPDU SIG field may be reserved, and bit 6 in the S1 G_1 M field may be reserved.

If the reserved bit, e.g. bit 6 in S1 G_1 M, indicates modulation PPDU format according to embodiments herein, while the MCS field is used to indicate the channel code and modulation order, e.g. MCS1 indicates Binary convolutional coding (BCC) rate ½ and Quadrature Phase Shift Keying (QPSK) modulation.

5 In another embodiment, the modulation PPDU format is used only if BCC is used in the channel code. If BCC is used then there is an unused bit in the SIG field, for all PPDU formats. For example in the S1 G_1 M PPDU SIG, bit 4 is unused whenever convolutional codes are used, while bit 18 is unused in the SHORT PPDU SIG. This unused bit may be employed to signal the modulation PPDU format according to

0 embodiments herein. The MCS field in the SIG field is used to indicate the channel code and modulation order.

In some embodiments the use of the modulation PPDU format according to embodiments herein is conditioned upon e.g.

5 - Type of STA. In particular whether the STA is a traditional non-AP STA or a

sensor STA.

- An order of the symbol constellation.

- Capabilities of the receiver.

- Channel bandwidth.

0 One or any combination of conditions mentioned above may be used. Figure 13 shows an embodiment depicting a process taking different conditions into account when determining whether to single-carrier modulate a part of all of the data payload. In one embodiment shown in Fig. 13, the modulation PPDU format according to embodiments herein is used only if the transmitting device 12 is a sensor STA, with a channel

5 bandwidth of not more than 1 MHz, the receiving device 10 is capable of decoding the modulation PPDU format according to embodiments herein, and BPSK modulation is used. In another embodiment, not shown, the PPDU format modulation according to embodiments herein may be used provided the transmitting device 12 is a non-AP STA, the channel bandwidth is 2 MHz or less, and the modulation order is 2 or less, i.e. BPSK or QPSK.

Figure 14 discloses some embodiments of the receiving device 10 for demodulating the PDU from the transmitting device 12. Figure 14 shows a block diagram of the receiving device 10 and the multicarrier modulation is exemplified using OFDM modulation.

Action 1401 . The receiving device 10 may perform packet detection, Automatic Gain Control (AGC), and/or coarse frequency correction using the STF in the preamble of the protocol data unit from the transmitting node 12.

Action 1402. The receiving device 10 may perform channel estimation and/or frequency correction using the LTF of the preamble of the protocol data unit from the transmitting device 12 as conventional 802.11 ah OFDM receivers. As stated above the preamble was modulated using a multicarrier modulation.

Action 1403. The receiving device 10 may acquire the information regarding the MCS, aggregation and packet format i.e. whether the PPDU format is the modulation PPDU format according to embodiments herein or not the modulation

PPDU format according to embodiments herein. This information may be carried in the SIG field in the preamble of the protocol data unit from the transmitting device 12.

Action 1404. From the previous action, the receiving device 10 determines whether the current data waveform is multicarrier modulated e.g. OFDM modulated or single-carrier modulated. E.g. the receiving device 10 may determine whether IFFT has been applied to a current constellation symbol or waveform.

Action 1405. If the data payload is multicarrier modulated then e.g. an

802.1 1ah demodulation chain is applied

Action 1406. If the data payload in single-carrier modulated, one or more constellation symbols of the waveform may be de-rotated.

Action 1407. The receiving device 10 may further apply an energy

compression prefilter on the single-carrier modulated part of the data payload.

Action 1408. The receiving device 10 may further then apply a trellis detector e.g. using a decision feedback sequence estimator and perform channel tracking in decision directed mode. This single-carrier demodulation receiver technology has been used in other wireless systems such as GSM/EDGE. Reference [2] explains efficient designs for energy compaction filters and reduced complexity demodulators.

Action 1409. The receiving device 10 may then channel decode the data

5 payload of the single-carrier waveforms and the multicarrier waveforms e.g. the

demodulated bits are fed to a channel decoder.

Fig. 15 is a schematic flowchart depicting a method performed by the transmitting device 12 for for transmitting data payload in a protocol data unit to the

1 o receiving device 10 in the wireless communication network 1 according to

embodiments herein. The protocol data unit comprises a preamble modulated into a multicarrier waveform and the data payload. The protocol data unit may be a PPDU. The wireless communications network may be a WLAN. A carrier frequency of the wireless communications network may be below 1 GHz. The preamble may comprise

1 5 information for receiving devices e.g. information of modulation format or training fields for channel estimation etc, see action 1401-1403, and as the preamble is multicarrier modulated legacy receiving devices are still able to read the information for receiving devices. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with

20 dashed boxes.

Action 1501 . The transmitting device 12 may determine whether to perform modulation of the part or all of the data payload in the protocol data unit using a single- carrier modulation based on one or more conditions. The one or more conditions are any or a combination of type of transmitting device; capability of the receiving device

25 10; modulation order of the protocol data unit; and channel bandwidth.

Action 1502. The transmitting device 12 may transmit an indication to the receiving device 10, which indication indicates that the transmitting device 12 modulates the part or all of the data payload in the protocol data unit into the single- carrier waveform. E.g. an indication in the SIG field of the preamble of the protocol data

30 unit.

Action 1503. The transmitting device 12 may modulate the preamble of the packet data unit into the multicarrier waveform using e.g. an OFDM modulation. The transmitting device may also multicarrier modulate a part of the data payload that is not single-carrier modulated into a multicarrier waveform. In some embodiments a cyclic 35 prefix insertion is used only in the multicarrier waveform of the preamble and/or the part of the data payload that is not single carrier modulated. The preamble may already be multicarrier modulated e.g. pre-configured.

Action 1504. The transmitting device 12 modulates a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier 5 waveform.

Action 1505. The transmitting device 12 may insert one or more training signals into the data payload, wherein said one or more training signals are known at both the transmitting device 12 and the receiving device 10.

Action 1506. The single-carrier waveform may be obtained by means of a o linear modulator, said linear modulator comprising a constellation rotation unit rotating one or more constellation symbols in the single-carrier modulation.

Action 1507. The transmitting device 12 transmits the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data payload of the single-carrier waveform to the receiving device 10.

5

The method actions performed the receiving device 10 for demodulating a waveform carrying data payload from the transmitting device 12 in the wireless communication network 1 according to some embodiments will now be described with reference to a flowchart depicted in Fig. 16. The actions do not have to be taken in the0 order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

Action 1601 . The receiving device 10 may receive an indication from the transmitting device 12, which indication indicates that the transmitting device 12 has applied single-carrier modulation to the part or all of the data payload in the protocol5 data unit.

Action 1602. The receiving device 10 receives the protocol data unit, from the transmitting device 12, which protocol data unit comprises the multicarrier modulated preamble with a multicarrier waveform and the data payload, wherein a part or all of the data payload is single-carrier modulated with a single-carrier waveform.

0 Action 1603. The receiving device 10 may use the multicarrier modulated

preamble for packet detection, frequency correction, Automatic Gain Control, and channel estimation.

Action 1604. The receiving device 10 determines whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit. The receiving device 10 may e.g. determine whether the single-carrier modulation has been applied based on the received indication.

Action 1605. The receiving device 10 demodulates the multicarrier modulated preamble.

5 Action 1606. The receiving device 10 when being determined that the single- carrier modulation has been applied to the part or all of the data payload in the protocol data unit, demodulates the part or all of the data payload in the protocol data unit that is single-carrier modulated. E.g. the receiving device may demodulate the part or all of the data payload by de-rotating one or more constellation symbols of the single-carrier o waveform or waveforms, apply an energy compaction filter to the single-carrier waveform and/or apply a trellis based bit estimator to the single-carrier waveform.

Figure 17 is a block diagram depicting the transmitting device 12 for transmitting data payload in a protocol data unit to the receiving device 10 in the5 wireless communication network 1. The protocol data unit comprises a preamble

modulated into a multicarrier waveform and the data payload. The transmitting device 12 is configured to modulate a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform. The transmitting device 12 is further configured to transmit the protocol data unit with the preamble of0 the multicarrier waveform and the part or all of the data payload of the single-carrier waveform to the receiving device 10.

The transmitting device 12 may further be configured to modulate the preamble of the packet data unit into the multicarrier waveform using an OFDM modulation. The transmitting device 12 may be configured to use a cyclic prefix insertion only in the5 multicarrier waveform. The preamble may comprise information for receiving devices.

The transmitting device 12 may be configured to insert one or more training signals into the data payload, wherein said one or more training signals are known at both the transmitting device 12 and the receiving device 10. Transmitting device 12 may comprise a linear modulator for obtaining the single-carrier waveform, said linear0 modulator comprising a constellation rotation unit configured to rotate one or more constellation symbols in the single-carrier modulation.

The transmitting device may be configured to determine whether to perform modulation of the part or all of the data payload in the protocol data unit using a single- carrier modulation based on one or more conditions. The one or more conditions may be any or a combination of: type of transmitting device; capability of the receiving device 10; modulation order of the protocol data unit; and channel bandwidth.

The transmitting device 12 may be configured to transmit an indication to the receiving device 10, which indication indicates that the transmitting device 12

5 modulates the part or all of the data payload in the protocol data unit into the single- carrier waveform.

The transmitting device 12 may comprise processing circuitry 1701 configured to perform the embodiments herein with one or more processors.

The transmitting device 12 may comprise a modulating module 1702. The o modulating module 1702 and/or the processing circuitry 1701 may be configured to modulate a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform. The modulating module 1702 and/or the processing circuitry 1701 may be configured to modulate the preamble of the packet data unit into the multicarrier waveform using an OFDM modulation. The preamble may 5 comprise information for receiving devices. The modulating module 1702 and/or the processing circuitry 1701 may be configured to use a cyclic prefix insertion only in the multicarrier waveform. The modulating module 1702 and/or the processing circuitry 1701 may be configured to insert one or more training signals into the data payload, wherein said one or more training signals are known at both the transmitting device 120 and the receiving device 10. The modulating module 1702 and/or the processing circuitry 1701 may comprise a linear modulator for obtaining the single-carrier waveform, said linear modulator further comprising a constellation rotation unit configured to rotate one or more constellation symbols of the single-carrier waveform.

The transmitting device 12 may comprise a transmitting module 1703. The5 transmitting module 1703 and/or the processing circuitry 1701 may be configured to transmit the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data payload of the single-carrier waveform to the receiving device 10. The transmitting module 1703 and/or the processing circuitry 1701 may be configured to transmit an indication to the receiving device 10, which indication indicates that the0 transmitting device 12 modulates the part or all of the data payload in the protocol data unit into the single-carrier waveform.

The transmitting device 12 may comprise a determining module 1704. The determining module 1704 and/or the processing circuitry 1701 may be configured to determine whether to perform modulation of the part or all of the data payload in the5 protocol data unit using a single-carrier modulation based on one or more conditions. The one or more conditions may be any or a combination of: type of transmitting device; capability of the receiving device 10; modulation order of the protocol data unit; and channel bandwidth.

The transmitting device 12 further comprises a memory 1705. The memory 5 comprises one or more units to be used to store data on, such as constellation symbols, symbol constellation used, receiving devices capability, type of transmitting device, modulation data, training signal/s, rotating angles, applications to perform the methods disclosed herein when being executed, and similar.

The methods according to the embodiments described herein for the transmitting o device 12 may be implemented by means of e.g. a computer program 1706 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the transmitting device 12. The computer program 1706 may be stored on a computer-readable storage medium 1707, e.g. a5 disc or similar. The computer-readable storage medium 1707, having stored thereon the computer program, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the transmitting device 12. In some embodiments, the computer-readable storage medium may be a non-transitory computer-readable storage medium.

0

Figure 18 is a block diagram depicting the receiving device 10 for demodulating a waveform carrying data payload from the transmitting device 12 in the wireless communication network 1. The receiving device 10 being configured to receive a protocol data unit, from the transmitting device 12, which protocol data unit comprises a5 multicarrier modulated preamble with a multicarrier waveform and the data payload. A part or all of the data payload is single-carrier modulated with a single-carrier waveform. The receiving device is further configured to determine whether a single- carrier modulation has been applied to the part or all of the data payload in the protocol data unit. In addition, the receiving device 10 is further configured to demodulate the0 multicarrier modulated preamble, and, when being determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, to demodulate the part or all of the data payload in the protocol data unit that is single-carrier modulated. The receiving device 12 may be configured to demodulate the part or all of the data payload by de-rotating one or more constellation symbols of the5 single-carrier waveform. The receiving device 10 may be configured to demodulate the part or all of the data payload by applying an energy compaction filter to the single- carrier waveform. The receiving device 10 may further be configured to demodulate the part or all of the data payload by applying a trellis based bit estimator to the single- carrier waveform.

5 The receiving device 10 may be configured to receive an indication from the transmitting device 12, which indication indicates that the transmitting device 12 has applied single-carrier modulation to the part or all of the data payload in the protocol data unit. The receiving device 10 may then be configured to determine whether the single-carrier modulation has been applied based on the received indication.

1 o The receiving device 10 may be configured to use the multicarrier modulated preamble for packet detection, frequency correction, Automatic Gain Control, and channel estimation.

The receiving device 10 may comprise processing circuitry 1801 configured to perform the methods herein with one or more processors.

1 5 The receiving device 10 may comprise a receiving module 1802. The

receiving module 1802 and/or the processing circuitry 1801 may be configured to receive a protocol data unit, from the transmitting device 12. The protocol data unit comprises a multicarrier modulated preamble with a multicarrier waveform and the data payload, wherein a part or all of the data payload is single-carrier modulated with a

20 single-carrier waveform.

The receiving device 10 may comprise a determining module 1803. The determining module 1803 and/or the processing circuitry 1801 may be configured to determine whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit.

25 The receiving device 10 may comprise a demodulating module 1804. The demodulating module 1804 and/or the processing circuitry 1801 may be configured to demodulate the multicarrier modulated preamble. Furthermore, when the determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, the demodulating module 1804 and/or the processing circuitry

30 1801 may be configured to demodulate the part or all of the data payload in the

protocol data unit that is single-carrier modulated. The demodulating module 1804 and/or the processing circuitry 1801 may be configured to demodulate the part or all of the data payload by de-rotating one or more constellation symbols of the single-carrier waveform. The demodulating module 1804 and/or the processing circuitry 1801 may

35 further be configured to demodulate the part or all of the data payload by applying an energy compaction filter to the single-carrier waveform. The demodulating module 1804 and/or the processing circuitry 1801 may be configured to demodulate the part or all of the data payload by applying a trellis based bit estimator to the single-carrier waveform.

5 The receiving module 1802 and/or the processing circuitry 1801 may be

configured to receive an indication from the transmitting device 12, which indication indicates that the transmitting device 12 has applied single-carrier modulation to the part or all of the data payload in the protocol data unit. The determining module 1803 and/or the processing circuitry 1801 may then be configured to determine whether the single- o carrier modulation has been applied based on the received indication.

The receiving device 10 may further comprise a using module 1805. The using module 1805 and/or the processing circuitry 1801 may be configured to use the multicarrier modulated preamble for packet detection, frequency correction, Automatic Gain Control, and channel estimation.

5 The transmitting device 12 further comprises a memory 1806. The memory comprises one or more units to be used to store data on, such as constellation symbols, symbol constellation used, receiving devices capability, AGCs, channel estimation data, demodulation data, training signal/s, de-rotating angles, applications to perform the methods disclosed herein when being executed, and similar.

0 The methods according to the embodiments described herein for the receiving device 10 may be implemented by means of e.g. a computer program 1807 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the receiving device 10. The computer5 program 1807 may be stored on a computer-readable storage medium 1808, e.g. a disc or similar. The computer-readable storage medium 1808, having stored thereon the computer program, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the receiving device 10. In some embodiments, the computer-readable0 storage medium may be a non-transitory computer-readable storage medium.

As will be readily understood by those familiar with communications design, that functions means or modules may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware. In some

embodiments, several or all of the various functions may be implemented together,5 such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a communication node, for example.

Alternatively, several of the functional elements of the processing means

5 discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term "processor" or "controller" as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory o (ROM) for storing software, random-access memory for storing software and/or

program or application data, and non-volatile memory. Other hardware, conventional and/or custom, may also be included. Designers of communications receivers will appreciate the cost, performance, and maintenance tradeoffs inherent in these design choices.

5 It will be appreciated that the foregoing description and the accompanying

drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the inventive apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

0

Claims

1. A method performed by a transmitting device (12) for transmitting data payload in a protocol data unit to a receiving device (10) in a wireless communication network (1), wherein the protocol data unit comprises a preamble modulated into a 5 multicarrier waveform and a data payload; the method comprising:

- modulating (1504) a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform; and

- transmitting (1507) the protocol data unit with the preamble of the multicarrier waveform and the part or all of the data payload of the single-carrier o waveform to the receiving device (10).

A method according to claim 1 , further comprising

- modulating (1503) the preamble of the packet data unit into the multicarrier waveform using an, Orthogonal Frequency-Division Multiplexing, OFDM, modulation.

3. A method according to any of the claim 1-2, wherein a cyclic prefix insertion is used only in the multicarrier waveform.

A method according to any of the claims 1-3, further comprising inserting (1505) one or more training signals into the data payload, wherein said one or more training signals are known at both the transmitting device (12) and the receiving device (10).

A method according to any of the claims 1-4, where the single-carrier waveform is obtained by means of a linear modulator, said linear modulator further comprising a constellation rotation unit, rotating (1506) one or more constellation symbols in the single-carrier modulation.

A method according to any of the claims 1-5, further comprising

- determining (1501) whether to perform the modulating (1504) of the part or all of the data payload in the protocol data unit using a single-carrier modulation based on one or more conditions.

7. A method according to claim 6, wherein the one or more conditions are any or a combination of: type of transmitting device; capability of the receiving device (10); modulation order of the protocol data unit; and channel bandwidth.

8. A method according to any of the claims 1-7, wherein the protocol data unit is a Physical Layer Convergence Protocol - Protocol Data Unit.

9. A method according to any of the claims 1-8, wherein the wireless

communications network is a Wireless Local Area Network, WLAN.

10. A method according to any of the claims 1-9, wherein a carrier frequency of the wireless communications network is below 1 GHz.

1 1. A method according to any of the claims 1-10, wherein the preamble comprises information for receiving devices.

12. A method according to any of the claims 1-11 , further comprising

- transmitting (1502) an indication to the receiving device (10), which indication indicates that the transmitting device (12) modulates the part or all of the data payload in the protocol data unit into the single-carrier waveform.

13. A method performed by a receiving device (10) for demodulating a waveform

carrying data payload from a transmitting device (12) in a wireless communication network (1); comprising

- receiving (1602) a protocol data unit, from the transmitting device (12), which protocol data unit comprises a multicarrier modulated preamble with a multicarrier waveform and the data payload, wherein a part or all of the data payload is single-carrier modulated with a single-carrier waveform;

- determining (1604) whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit;

- demodulating (1605) the multicarrier modulated preamble; and

- when being determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, demodulating (1606) the part or all of the data payload in the protocol data unit that is single- carrier modulated.

14. A method according to claim 13, wherein the demodulating (1606) the part or all of the data payload comprises de-rotating one or more constellation symbols of the single-carrier waveform.

5 15. A method according to any of the claims 13-14, wherein the demodulating (1606) the part or all of the data payload comprises applying an energy compaction filter to the single-carrier waveform.

16. A method according to any of the claims 12-14, wherein the demodulating (1606) o the part or all of the data payload comprises applying a trellis based bit estimator to the single-carrier waveform.

17. A method according to any of the claims 12-15, further comprising

- receiving (1601) an indication from the transmitting device (12), which 5 indication indicates that the transmitting device (12) has applied single-carrier modulation to the part or all of the data payload in the protocol data unit; and the determining (1604) whether the single-carrier modulation has been applied is based on the received indication.

18. A method according to any of the claims 12-16, further comprising

- using (1603) the multicarrier modulated preamble for packet detection, frequency correction, Automatic Gain Control, and channel estimation.

19. A transmitting device (12) for transmitting data payload in a protocol data unit to a5 receiving device (10) in a wireless communication network (1), wherein the

protocol data unit comprises a preamble modulated into a multicarrier waveform and the data payload; wherein the transmitting device is configured to:

modulate a part or all of the data payload in the protocol data unit using a single-carrier modulation into a single-carrier waveform; and

0 transmit the protocol data unit with the preamble of the multicarrier

waveform and the part or all of the data payload of the single-carrier waveform to the receiving device (10).

20. A transmitting device (12) according to claim 19, further being configured to modulate the preamble of the packet data unit into the multicarrier waveform using an Orthogonal Frequency-Division Multiplexing, OFDM, modulation.

21. A transmitting device (12) according to any of the claim 19-20, being configured to use a cyclic prefix insertion only in the multicarrier waveform.

22. A transmitting device (12) according to any of the claims 19-21 , further being

configured to insert one or more training signals into the data payload, wherein said one or more training signals are known at both the transmitting device (12) and the receiving device (10).

23. A transmitting device (12) according to any of the claims 19-22, comprising a

linear modulator for obtaining the single-carrier waveform, said linear modulator further comprising a constellation rotation unit configured to rotate one or more constellation symbols of the single-carrier waveform.

24. A transmitting device (12) according to any of the claims 19-23, further configured to determine whether to perform modulation of the part or all of the data payload in the protocol data unit using a single-carrier modulation based on one or more conditions.

25. A transmitting device (12) according to claim 24, wherein the one or more

conditions are any or a combination of: type of transmitting device; capability of the receiving device (10); modulation order of the protocol data unit; and channel bandwidth.

26. A transmitting device (12) according to any of the claims 19-25, wherein the

preamble comprises information for receiving devices.

27. A transmitting device (12) according to any of the claims 19-26, further being

configured to transmit an indication to the receiving device (10), which indication indicates that the transmitting device (12) modulates the part or all of the data payload in the protocol data unit into the single-carrier waveform.

28. A receiving device (10) for demodulating a waveform carrying data payload from a transmitting device (12) in a wireless communication network (1); being configured to:

receive a protocol data unit, from the transmitting device (12), which protocol data unit comprises a multicarrier modulated preamble with a multicarrier waveform and the data payload, wherein a part or all of the data payload is single- carrier modulated with a single-carrier waveform;

determine whether a single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit;

demodulate the multicarrier modulated preamble; and

when being determined that the single-carrier modulation has been applied to the part or all of the data payload in the protocol data unit, being configured to demodulate the part or all of the data payload in the protocol data unit that is single-carrier modulated.

29. A receiving device (10) according to claim 28, being configured to demodulate the part or all of the data payload by de-rotating one or more constellation symbols of the single-carrier waveform.

30. A receiving device (10) according to any of the claims 28-29, being configured to demodulate the part or all of the data payload by applying an energy compaction filter to the single-carrier waveform.

31. A receiving device (10) according to any of the claims 28-30, being configured to demodulate the part or all of the data payload by applying a trellis based bit estimator to the single-carrier waveform.

32. A receiving device (10) according to any of the claims 28-31 , further being

configured to receive an indication from the transmitting device (12), which indication indicates that the transmitting device (12) has applied single-carrier modulation to the part or all of the data payload in the protocol data unit; and being configured to determine whether the single-carrier modulation has been applied based on the received indication.

33. A receiving device (10) according to any of the claims 28-32, further being configured to use the multicarrier modulated preamble for packet detection, frequency correction, Automatic Gain Control, and channel estimation.