Communication devices and methods

Abstract

A first communication device that is configured to communicate with one or more second communication devices comprises circuitry configured to encode data to be transmitted to one or more second communication devices into one or more data streams; generate a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; map the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and transmit the data unit on the plurality of tones according to the mapping of the data onto the different resource units.

Description

WITTEWELLERP A T E N T A N W A L T EApplicants:Sony Group Corporation 18.09.2025 1-7-1 Konan 4727P380WO - SKMinato-KuTokyo 108-0075JAPANSONY Europe Limited The Heights, Brooklands, Weybridge, SurreyKT13 0XWUNITED KINGDOMCOMMUNICATION DEVICES AND METHODSBACKGROUNDFIELD OF THE DISCLOSURE

[0001] The present disclosure relates first and second communication devices that are configured to communicate with each other. The present disclosure relates further to corresponding first and second communication methods.DESCRIPTION OF RELATED ART

[0002] Orthogonal frequency division multiple access (OFDMA) was introduced to IEEE 802.11 standards related to WLAN. This feature allocates resource units (RUs) to different stations (STAs) in the frequency domain. The Rlls are composed of groups of subcarriers ofstandardized sizes (e.g., 26, 52, 106 tone RUs, etc.), and they remain unchanged within the transmission of a data unit, such as within a physical layer protocol data unit (PPDll) transmission.

[0003] IEEE P802.11bn aims at achieving ultra-high reliability (UHR) for WLAN. Channel diversity is an important component to increase reliability in communications over fading channels like the ones present in WLAN. The typical WLAN channels change slowly in time but can have high frequency selectivity. By spreading the encoded data streams over several subcarriers or tones, the diversity of frequency selective channels is exploited.

[0004] OFDMA transmissions can accommodate several STAs in a PPDU efficiently. However, for low RU sizes the number of subcarriers used to harvest channel diversity can be low compared to the total diversity degree over the full PPDU bandwidth.

[0005] The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.SUMMARY

[0006] It is an object to increase the frequency diversity of OFDMA and / or extended range transmissions in WLAN. It is a further object to provide corresponding communication devices and methods as well as a corresponding computer program and a non-transitory computer-readable recording medium that stores therein a computer program product for implementing said methods.

[0007] According to an aspect there is provided a first communication device configured to communicate with one or more second communication devices, the first communication device comprising circuitry configured to:encode data to be transmitted to one or more second communication devices into one or more data streams; generate a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; map the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and transmit the data unit on the plurality of tones according to the mapping of the data onto the different resource units.

[0008] According to a further aspect there is provided a second communication device configured to communicate with a first communication devices, the second communication device comprising circuitry configured to: receive a data unit including a preamble and a data field, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones; determine mapping information indicating if and how the mapping of the data of the one or more data streams onto different resource units within the data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and demap the one or more data streams addressed to the second communication device from the received data unit according to the determined mapping information.

[0009] According to still further aspects corresponding methods, a computer program comprising program means for causing a computer to carry out the steps of the method disclosed herein, when said computer program is carried out on a computer, as well as a non-transi- tory computer-readable recording medium that stores therein a computer programproduct, which, when executed by a processor, causes the methods disclosed herein to be performed are provided.

[0010] Embodiments are defined in the dependent claims. It shall be understood that the disclosed methods, the disclosed computer program and the disclosed computer-readable recording medium have similar and / or identical further embodiments as the claimed devices and as defined in the dependent claims and / or disclosed herein.

[0011] One of the aspects of the disclosure is to dynamically change / switch the allocation of data streams to RUs and to change the frequency mapping operation to assign data streams to different Rlls for different data symbols, such as OFDM symbols, within a data unit, such as a PPDll. This increases the frequency diversity of OFDMA and / or extended range transmissions in WLAN.

[0012] The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWING

[0013] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:Fig. 1 shows the different regular resource units of WLAN for 20 MHz, 40 MHz and 80 MHz.Fig. 2 shows a diagram illustrating a conventional OFDMA operation.Fig. 3 shows a diagram illustrating the proposed dynamic frequency mapping (DFM) method.Fig. 4 shows a schematic diagram of an exemplary embodiment of a communication device according to the present disclosure.Fig. 5 shows a schematic diagram of another exemplary embodiment of a communication device according to the present disclosure.Fig. 6A shows a first embodiment of a DFM tone set according to the present disclosure.Fig. 6B shows a second embodiment of a DFM tone set according to the present disclosure.Fig. 7 shows an exemplary Rll allocation of five 26-tone Rlls and two 52-tone Rlls for a 20 MHz PPDU.Fig. 8 shows the location of pilot tones and data tones of different Rlls A-D shown in Fig. 7.Fig. 9 shows a diagram of a scenario in which the present disclosure may be applied.Fig. 10 shows a flow chart of an embodiment of a first communication method according to the present disclosure.Fig. 11 shows a flow chart of an embodiment of a second communication method according to the present disclosure.Fig. 12 shows a schematic diagram of some blocks of an AP according to an embodiment of the present disclosure to illustrate the DFM operation with two 106- tone Rlls.Fig. 13A shows a diagram illustrating the DFM operation with nine 26-tone Rlls showing circular shifts according to an embodiment of the present disclosure.Fig. 13B shows a diagram illustrating the DFM operation with nine 26-tone Rlls showing other circular shifts according to an embodiment of the present disclosure.Fig. 14A shows a diagram illustrating the DFM operation with an unallocated 26-tone Rll with dynamic allocation according to an embodiment of the present disclosure.Fig. 14B shows a diagram illustrating the DFM operation with an unallocated 26-tone Rll without dynamic allocation according to an embodiment of the present disclosure.Fig. 15 shows a diagram illustrating mixed Rll allocation with and without DFM according to an embodiment of the present disclosure.Fig. 16 shows a diagram illustrating DMF joint operation for 26-tone and 52-tone Rlls according to an embodiment of the present disclosure.Fig. 17A shows a diagram illustrating DFM operation with replicated data streams according to an embodiment of the present disclosure.Fig. 17B shows a diagram illustrating DFM operation with replicated data streams according to another embodiment of the present disclosure.Fig. 18 shows a diagram of DFM signaling within a ll-SIG according to an embodiment of the present disclosure.Fig. 19 shows a diagram of DFM signaling within a UHR-SIG according to an embodiment of the present disclosure.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, Fig. 1 shows the different regular resource units (rRUs) of WLAN for 20 MHz (Fig. 1A), 40 MHz (Fig. 1 B) and 80 MHz (Fig. 1C). There are guard subcarriers, null subcarriers, and data subcarriers. It shall be noted in this context that the terms “subcarriers”, “carriers” and “tones” are equivalently used herein and shall be understood as meaning the same.

[0015] In a downlink transmission, i.e. , a transmission from an AP to one or more STAs, the data for each STA may be contained in an RU. For example, different data to two STAs can be multiplexed in downlink in two 106 tone RUs. Similarly, in uplink transmission, i.e., transmission from one or more STAs to an AP, each STA puts its data to be transmitted on a distinct RU. Since the transmit data is contained in different RUs the data is multiplexed in frequency and can be retrieved without mutual interference.

[0016] Fig. 2 shows a diagram illustrating a conventional OFDMA operation, according to which RUs are allocated to different STAs in the frequency domain. The RUs are composed of groups of subcarriers of standardized sizes (e.g., 26, 52, 106 tone RUs, etc.), and they remain unchanged within a PPDU transmission from an access point (AP), which may represent a first communication device according to an embodiment of the present disclosure, to the STAs, which may represent second communication devices according to an embodiment of the present disclosure. The PPDU 10 shown in Fig. 2 comprises a preamble 11 and a data field 12. The data field 12 comprises a plurality of data symbols (e.g. OFDM symbols) to be carried on a plurality of tones / subcarriers, each data symbol including data from one or more data streams. The data is generally encoded data into one or more data streams to be transmitted to one or more STAs, wherein generally to each STA a different data stream is to be transmitted. As shown in Fig. 2, a first data stream is transmitted to STA 1 and a second data stream is transmitted to STA 2.

[0017] The data of the one or more data streams included in a data symbol are mapped onto different resource units (RUs) to which the plurality of tones is allocated, each Rll having a predetermined number of the plurality of tones. In example shown in Fig. 2, two Rlls 13, 14 are included in the data field 12. The first Rll 13 covers a first number of tones / subcarriers and is allocated to STA 1. The second Rll 14 covers a second number of tones / subcarriers and is allocated to STA 2. The two data streams for the two STAs 1, 2 are included in the data field 12 of the PPDll 10 and are transmitted via several OFDM symbols of the PPDll 10, i.e., the data of the first data stream for STA 1 are carried by Rll 13 and the data of the second data stream for STA 2 are carried by Rll 14.

[0018] IEEE P802.11bn aims at achieving ultra-high reliability (UHR) for WLAN. Channel diversity is an important component to increase reliability in communications over fading channels like the ones present in WLAN. The typical WLAN channels change slowly in time but can have high frequency selectivity. By spreading the encoded data streams over several subcarriers or tones, the diversity of frequency selective channels is exploited.

[0019] OFDMA transmissions can accommodate several STAs in a PPDU efficiently. However, for low RU sizes the number of subcarriers used to harvest channel diversity can be low compared to the total diversity degree over the full PPDU bandwidth.

[0020] According to the present disclosure, a dynamic frequency mapping (DFM) method is proposed to increase the frequency diversity within PPDU transmissions with multiple RUs. Fig. 3 shows a diagram illustrating the proposed DFM method. The main idea is to switch the allocation of data streams between RUs for multiple OFDM symbols. In Fig. 3, RUs in data symbols 21-25 are allocated to a first data stream to be transmitted to STA 1 and RUs in data symbols 26-30 are allocated to a second data stream to be transmitted to STA 2. This allows for data streams to experience channel variations in more subcarriers than the ones limited by the RU size.

[0021] Fig. 4 shows a schematic diagram of an exemplary embodiment of a communication device 40, in particular a transmitter, such as an AP, which implements the disclosed DFM operation. According to this embodiment the frequency mapping operation for OFDMmodulation (carried out in block 47) is modified compared to the conventional operation. Generally, the OFDM modulation takes complex modulated symbols corresponding to a data stream assigned to a specific number of tones and performs an inverse Fourier transform or inverse fast Fourier transform resulting in OFDM data symbols. According to embodiments of the present disclosure, data symbols carried on a plurality of tones refer to OFDM modulated symbols.

[0022] Embodiments of the present disclosure focus on changes to the frequency mapping, thus without loss of generality, it may be considered that one data stream corresponds to parsed data to be allocated to a specific Rll containing a PHY service data unit (PSDll) intended for a specific STA. This data stream can be composed of one or more spatial streams that are mapped to transmit antennas by the spatial mapping operation.

[0023] After forward error correction (FEC) encoding by a FEC encoder 41 and stream parser operation by a stream parser 42, data streams are obtained, where the encoded data bits are processed in groups that fit into a predetermined number of data tones, fitting within an Rll, for each OFDM symbol. The data streams are then mapped into constellation points by the constellation mapper 43 and are later mapped into data tones by a spatial and frequency mapper 47, after the operations of an LDPC tone mapper 43 and a cyclic shift diversity unit 44 and the optional operation of a data stream replication unit 46. After the spatial and frequency mapper 47, conventional operations of an inverse discrete Fourier transform (IDFT) unit 48, and insertion unit 49 (for insertion of guard intervals (Gl) and windowing operation) and an analog RF unit 50. Thus, Fig. 4 shows a transmitter block diagram for encoded bits from a PSDll being mapped to data streams and further mapped to a specific Rll.

[0024] Fig. 5 shows a schematic diagram of another exemplary embodiment of a communication device 40’, in particular a transmitter for transmitting data to two STAs. PSDlls intended to different STAs are encoded and parsed into data streams being mapped to different Rlls. The general processing is identical to the processing illustrated in and explained with reference to Fig. 4.

[0025] An optional stream replication unit 46 can be added before the frequency mapper 47. This means that the same data stream is mapped to two or more Rlls and the DFM allows replicated data streams to experience more channel variations. The combination of data stream replication and DFM increases the reliability of transmissions further compared to simple replication. The data stream replication can be implemented at any point after the stream parser 42 and before the frequency mapper 47. Details of the stream replication will be explained below.

[0026] A DFM Rll set or tone set (i.e. a set of subcarriers) can be defined to identify the Rlls that are subject to DFM as shown in Fig. 6. The set of Rlls may be identified by specific Rll indices. For example, the 26-tone Rll 1 to 4 as shown in Fig. 6A or the 26-tone Rll 1 to 9 as shown in Fig. 6B may be part of DFM. Alternatively, the set of Rlls can be identified by a tone / subcarrier interval. For example, all Rlls inside tone interval -121 to -17 as shown in Fig. 6A or all Rlls inside tone interval-121 to 121 as shown in Fig. 6B may be part of DFM.

[0027] Fig. 7 shows an exemplary Rll allocation of five 26-tone Rlls and two 52-tone Rlls for a 20 MHz PPDll. Fig. 8 shows the location of pilot tones and data tones of different Rlls A- D shown in Fig. 7. Generally, each Rll has a predetermined number of data tones and pilot tones. The location of the pilot tones within each Rll can be different depending on the frequency mapping that each Rll has, as illustrated in Fig. 8 for 26-tone Rlls A and B as well as 52-tone Rlls C and D. The pilot tones are used by the receiver for phase tracking operation, and it is important that they remain fixed for the entire duration of the PPDll. Thus, the implementation of DFM is applied only to the data tones of each Rll. In addition, the receiver STA should perform phase tracking operation based on the received pilots of all Rlls locations that are part of the DFM operation. Furthermore, the training fields are also left unchanged when DFM is implemented.

[0028] Fig. 9 shows a diagram of a scenario in which the present disclosure may be applied. It shows particularly a communication system including a first communication device 100 (which in an embodiment may be access point (AP) and one or more second communication devices 110, 120 (which in an embodiment may be stations (STA)). The first communication device 100 is generally able to communicate with the one or more secondcommunication devices 110, 120, e.g. to exchange (receive and / or transmit) data with the second communication devices 110, 120. Each of the communication device 100, 110, 120 comprises circuitry 101 , 111 , 121 that is configured to perform particular operations. The circuitries may be implemented by a respective processor or computer, i.e., as hardware and / or software, or by dedicated units or components. For instance, respectively programmed processors may represent the respective circuitries 101 , 111 , 121.

[0029] Fig. 10 shows a flow chart of an embodiment of a first communication method 200 of the first communication device 100 according to the present disclosure, which may be performed by the circuitry 101. In a first step 201 , the first communication device 100 encodes data to be transmitted to one or more second communication devices into one or more data streams. In a second step 202, a data unit is generated from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams. In a third step 203, the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit. In a fourth step 204, the data unit is transmitted on the plurality of tones according to the mapping of the data onto the different resource units.

[0030] Fig. 11 shows a flow chart of an embodiment of a second communication method 210 of the second communication device 110 according to the present disclosure, which may be performed by the circuitry 111. The same method 210 may be carried out by the second communication device 120 as well. In a first step 211 , the second communication device 110, a data unit including a preamble and a data field is received, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones. In a second step 212, mapping information is determined indicating if and how the mapping of the data of the one or more data streams onto different resource units withinthe data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit. In a third step 213, the one or more data streams addressed to the second communication device are demapped from the received data unit according to the determined mapping information.

[0031] In the following, different embodiments of DFM operation according to the present disclosure will be explained. Generally, the mapping of the data to the Rlls and the changes of the mapping from one OFDM symbol to the next OFDM symbol may generally be made according to a rule, algorithm, standard, or even randomly.

[0032] Fig. 12 shows a schematic diagram of some blocks of an AP 50 according to an embodiment of the present disclosure to illustrate the DFM operation with two 106-tone Rlls. For two data streams intended for STA 1 and STA 2, respectively, a respective constellation or LDPC tone mapper 51 , 52 and a common dynamic frequency mapper 53 are shown in Fig. 12. The conventional operation (shown at the bottom) includes that data to each STA is encoded and parsed into data streams, which are fed to the constellation mapper 51, 52 (and LDPC tone mapper if applicable). The data at the output of the constellation mapper is organized in blocks of data tones and OFDM symbols (one OFDM symbol is indicated as 60).

[0033] According to the present disclosure, the data tones allocated to each Rll for each OFDM symbol are switched in an alternating fashion by the dynamic frequency mapper 53, as indicated on the right-hand side. As indicated by the different patterns the 106-tone Rll 1 thus alternately (from OFDM symbol to OFDM symbol) carries data of the first data stream and the second data stream. The same holds for the 106-tone Rll 2. For instance, in the OFDM symbol 61, the 106-tone Rll 1 carries data of the first data stream directed to STA 1 and the 106-tone Rll 2 carries data of the second data stream directed to STA 2. In the next OFDM symbol 62, the 106-tone Rll 1 carries data of the second data stream directed to STA 2 and the 106-tone Rll 2 carries data of the first data stream directed to STA 1. The middle 26-tone Rll is left unchanged; it can have data to another STA or can be left empty.

[0034] Figs. 13A and 13B show diagrams illustrating the DFM operation with nine 26-tone RUs showing different circular shifts according to embodiments of the present disclosure. In this embodiment all Rlls are allocated to STAs. The alternation between Rlls and OFDM symbols should be in a predictable manner, e.g., including a cyclic alternating pattern, which requires the least amount of signaling. In the examples shown in Fig. 13, the Rlls are shifted circularly in frequency from symbol to symbol by a factor of 1 (Fig. 13A) and 4 (Fig. 13B). In particular, fixed circular shifts (e.g., 1, 2, 4, and 8) can be an efficient implementation. In addition, the shifts can be larger for PPDlls with larger bandwidth (e.g., 40MHz, 80 MHz, 160 MHz, and 320 MHz).

[0035] Figs. 14A and 14B show diagrams illustrating the DFM operation with an unallocated 26- tone Rll with and without dynamic allocation according to embodiments of the present disclosure. Generally, some Rlls may be unallocated. The alternation pattern can include empty Rlls (as shown in Fig. 14A) in which case the pilot symbols should still be transmitted in the empty Rll to simplify phase tracking at the receiver. Alternatively, the empty Rlls are not part of the alternation pattern and remain fixed for all OFDM symbols. In this case they do not require pilot transmission (as shown in Fig. 14B).

[0036] If some Rlls are unallocated, training fields should always be present in Rlls where there is allocated data on at least one OFDM symbol. If some Rlls are unallocated for all OFDM symbols, the training field tones corresponding to the unallocated Rll may be left empty.

[0037] Fig. 15 shows a diagram illustrating mixed Rll allocation with and without DFM according to an embodiment of the present disclosure. To enable DFM operation for devices with and without DFM capabilities in the same PPDll, it is possible to perform DFM for a subset of Rlls within the PPDll bandwidth (the upper part of the Rlls of the PPDll shown in Fig. 15) and leave the rest with a fixed Rll allocation (the lower part of the Rlls of the PPDll shown in Fig. 15).

[0038] According to further embodiments of the present disclosure, switching may be made between RUs of different sizes. In this operation the mapping of data streams corresponding to two small RUs may be switched with the frequency location of a larger size RU, e.g.,the 2x24 data tones of two 26-tone Rlls are switched with the 48 data tones of a 52-tone Rll. To apply DFM for different sizes, smaller size Rlls may be grouped such that the added number of data tones corresponds to the same number of data tones that are found in a larger Rll size. The following Rll sizes are compatible examples: i) 2x26-tone Rlls (with 24 data tones each) with one 52-tone Rll (having 48 data tones); and ii) 2x242- tone Rlls (with 234 data tones each) with one 484-tone Rll (having 468 data tones).

[0039] Fig. 16 shows a diagram illustrating DMF joint operation for 26-tone and 52-tone Rlls according to an embodiment of the present disclosure. According to this embodiment two 26-tone Rlls can be switched with a 52-tone Rll. The circular frequency shift is done in steps of two Rlls neglecting the middle Rll position. The middle Rll can be left empty of data tones that are not switched within the PPDll. An optional switch can be done for adjacent 26 tone Rlls pairs every fourth symbol to extend the symbol distance between small Rll repeated allocations.

[0040] Figs. 17A and 17B show diagrams illustrating DFM operation with replicated data streams according to embodiments of the present disclosure. In particular, an example of DFM operation and replication of the data streams allocated to a 26-tone Rll two times resulting in three Rlls containing the same data streams is illustrated. In case the DFM pattern involves a fixed circular frequency shift (in Fig. 17A with x1 circular shift; in Fig. 17B with x4 circular shift) it can happen that replicated Rlls do not change for different circular Rll shifts as shown in Figs. 17A and 17B. This simplifies the required signaling for DFM operation since the replicated assignment can be made implicit. For simplified operation, the same constellation mapping and tone mapping operation before DFM may be applied for all replicated streams. At the receiver STA, the combination of replicated data streams can be done by adding the demodulated complex symbols after channel equalization corresponding to the same data tones within each replicated Rll. Alternatively, the log likelihood values after constellation demapping can be combined.

[0041] To enable the receiver to correctly decode a PPDll using DFM, it needs to know the following basic information:Indication of DFM usage and type;Rll allocation of Rlls with and without DFM; andDFM pattern information.This information can be sent by the transmitter via certain indications, herein also called mapping information. Several signaling examples, based on preamble definitions of IEEE 802.11, will be described in the following. It should be noted, however, that other ways of signaling are possible as well.

[0042] Fig. 18 shows a diagram of DFM signaling within a universal signaling field (ll-SIG) according to an embodiment of the present disclosure. The ll-SIG is a forward compatible signaling field that contains version independent and dependent fields. For UHR the version dependent fields could be modified to include a DFM indication corresponding to the usage and / or type of DFM operation.

[0043] Fig. 19 shows a diagram of DFM signaling within an ultra-high reliability signaling field (UHR-SIG) according to an embodiment of the present disclosure. The UHR-SIG contains additional information to interpret the PPDll with multiple Rlls (e.g., MU-PPDU). In this field the basic Rll allocation can be conveyed in addition to a DFM field indicating one or more of: DFM pattern, DFM RU / tone set, number of replicated Rlls and identifier of Rlls carrying replicated data streams. The UHR-SIG contains a common info field with information common to all STAs and user info filed with specific information to STAs decoding specific RUs. A particular DFM pattern indication can be made by adding information in each user info field regarding the next RU in the DFM pattern. This can be done by modifying the interpretation of specific subfield for not supported configurations (e.g., MCS, NSS, coding), for example MCS and NSS values above certain threshold in combination with an indication in the common info field should be interpreted as the next RU in the DFM pattern. Alternatively, an additional subfield or user info field can be added.

[0044] According to a further embodiment implicit signaling may be used. It is not always necessary to explicitly indicate all items as indicated above in the mapping information, but it is also possible to define fixed standardized configurations for the DFM pattern in combination with RU allocation and / or replicated streams that can be signaled more efficiently.

[0045] In summary, according to an embodiment of the present disclosure, in the transmitter data is encoded to one or more STAs and parsed into one or more data streams. The data to each STA corresponds to a PSDll. Each data streams carries data from a different PSDll. A PPDll including at least a data field carried by OFDM symbols spanning a plurality of tones is created, wherein the tones of the data field are divided into two or more Rlls. One or more data streams are mapped to the Rlls. The frequency mapping of data streams to Rlls is changed for at least two Rlls between different OFDM symbols. The mapped data streams are modulated into OFDM symbols. Finally, the PPDll is transmitted.

[0046] Preferably, in the transmitter the frequency mapping may be switched according to different types of DFM operation. The data streams assigned to different Rlls may correspond to different receiver STAs unless stream replication is used. For instance, the data to two different receiver STAs may multiplexed in different Rlls. A data stream can be composed of one or more spatial streams. A data stream may be replicated into one or more replicated data streams, and each replicated data stream may be assigned to a different Rll. One or more of the following pieces of mapping information may be signaled: Usage of DFM operation;RU allocation for any OFDM symbol, in particular RU allocation of first OFDM symbol in data field;Set of RUs involved in DFM operation, wherein the definition of a DFM RU set includes the RUs to be subject to DFM;DFM pattern;Number of replicated data streams;Identifier of RUs carrying replicated data streams;Unallocated RUs; and- Type of DFM (equal size RUs, different size RUs, mixed fixed and dynamic RU DFM, replicated RUs with DFM).

[0047] Further, according to an embodiment of the present disclosure, in the receiver a PPDU is received including at least a data field carried by OFDM symbols spanning a plurality of tones wherein the tones of the data field are divided into two or more RUs. The OFDM symbols are demodulated. Data streams from at least two RUs are demapped with switched frequency mapping between different OFDM symbols.

[0048] Preferably, in the receiver one or more indications (mapping information) transmitted by the transmitter STA are received and the frequency demapping operation is configured based on the received one or more indications. Demapped data streams corresponding to replicated data streams may be combined. A phase tracking operation may be performed based on pilots received from all Rlls included in the switched frequency mapping that contained a data stream addressed to the receiver STA.

[0049] The device may be implemented by respective units or circuitry, e.g. a processor, processing circuitry, a computer, dedicated hardware, etc., that carries out the functions of the device. Alternatively, a common unit or circuitry, e.g. a common processor or computer, may implement the various functions of the device, or separate units or elements may be used that together represent the circuitry.

[0050] Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present disclosure. As will be understood by those skilled in the art, the present disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present disclosure is intended to be illustrative, but not limiting of the scope of the disclosure, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, defines, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.

[0051] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0052] In so far as embodiments of the disclosure have been described as being implemented, at least in part, by software-controlled data processing apparatus, it will be appreciated that a non-transitory machine-readable medium carrying such software, such as an optical disk, a magnetic disk, semiconductor memory or the like, is also considered to representan embodiment of the present disclosure. Further, such a software may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0053] The elements of the disclosed devices, apparatus and systems may be implemented by corresponding hardware and / or software elements, for instance appropriate circuits or circuitry. A circuit is a structural assemblage of electronic components including conventional circuit elements, integrated circuits including application specific integrated circuits, standard integrated circuits, application specific standard products, and field programmable gate arrays. Further, a circuit includes central processing units, graphics processing units, and microprocessors which are programmed or configured according to software code. A circuit does not include pure software, although a circuit includes the above-described hardware executing software. A circuit or circuitry may be implemented by a single device or unit or multiple devices or units, or chipset(s), or processor(s).

[0054] It follows a list of further embodiments of the disclosed subject matter:1. First communication device configured to communicate with one or more second communication devices, the first communication device comprising circuitry configured to: encode data to be transmitted to one or more second communication devices into one or more data streams; generate a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; map the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; transmit the data unit on the plurality of tones according to the mapping of the data onto the different resource units.2. First communication device according to any preceding embodiment,wherein the circuitry is configured to change the mapping of the data of the one or more data streams onto different resource units within the data unit for multiple data symbols of the data unit or from one data symbol to another data symbol for all data symbols of the data unit.3. First communication device according to any preceding embodiment, wherein the circuitry is configured to replicate one or more data streams and to map the one or more replicated data streams onto one or more other resource units than the data streams that have been replicated.4. First communication device according to any preceding embodiment, wherein the circuitry is configured to change the mapping of the data of the one or more data streams onto different resource units within the data unit only for a first tone set covering a first number of tones of the plurality of tones and use a fixed mapping of the data of the one or more data streams onto different resource units within the data unit for a second tone set covering the remaining number of tones of the plurality of tones.5. First communication device according to embodiment 4, wherein the circuitry is configured to indicate the first tone set by resource unit indices indicating the resource units to which the first number of tones of the first tone set are allocated or by tone indices and / or tone intervals indicating the first number of tones of the first tone set.6. First communication device according to any preceding embodiment, wherein the circuitry is configured to apply predetermined, random- or rule-based changes of the mapping.7. First communication device according to any preceding embodiment, wherein the circuitry is configured to generate mapping information indicating if and how changes of the mapping have been applied.8. First communication device according to any preceding embodiment,wherein the circuitry is configured to generate mapping information including an indication of one or more of: the usage of changes of the mapping; resource unit allocation for one or more of the data symbols of the data unit, in particular of the resource unit allocation of the first data symbol of the data unit; a first tone set and / or resource unit set, for which changes of the mapping are applied; the way of changing the mapping, in particular if predetermined, random- or rulebased changes of the mapping are applied; one or more replicated data streams; one or more resource units carrying one or more replicated data streams; unallocated resource units; the application of changes of the mapping, in particular if the resource units all have equal size or different sizes, if there are resource units that are used for changing the mapping and which are not used for changing the mapping, and / or if there are replicated resource units.9. First communication device according to embodiment 7 or 8, wherein the circuitry is configured to include the mapping information into the preamble of the data unit, in particular into a signaling field of the preamble.10. First communication device according to any preceding embodiment, wherein the circuitry is configured to change the mapping of the data onto different resource units without modifying the location of the pilot tones of the resource units.11 . First communication device according to any preceding embodiment, wherein the circuitry is configured to encode the data to be transmitted to the one or more second communication devices into one or more data streams, each data stream carrying data from a different physical layer service data unit, PSDll, directed to a particular second communication device; andgenerate the data unit as physical layer protocol data unit, PPDll, including a data field carrying the data streams in the form of orthogonal frequency division multiplexing, OFDM, data symbols.12. First communication device according to any preceding embodiment, wherein the circuitry is configured to fix the mapping of a first data symbol and change the mapping of subsequent data symbols by applying a circular shift to the resource unit allocation of a previous data symbol.13. First communication device according to any preceding embodiment, wherein the circuitry is configured to transmit pilot tones for unallocated resources units that are subject to mapping changes, and / or to change the mapping between resource units having the same number of tones or between two resource units with a resource unit having double number of tones.14. Second communication device configured to communicate with a first communication devices, the second communication device comprising circuitry configured to: receive a data unit including a preamble and a data field, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones; determine mapping information indicating if and how the mapping of the data of the one or more data streams onto different resource units within the data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and demap the one or more data streams addressed to the second communication device from the received data unit according to the determined mapping information.15. Second communication device according to embodiment 14,wherein the circuitry is configured to determine the mapping information from a standard or a previous agreement with the first communication device or from signaling information included in the received data unit.16. Second communication device according to embodiment 14 or 15, wherein the circuitry is configured to determine which different resource units contain data streams corresponding to replicated data streams and to combine the replicated data streams mapped onto said different resource units.17. Second communication device according to one of the embodiments 14 to 16, wherein the circuitry is configured to perform phase tracking based on pilot tones received from the resource units containing a data stream addressed to the second communication device and to include pilot tones from other resource units for which changes of the mapping have been applied.18. First communication method of a first communication device configured to communicate with one or more second communication devices, the first communication method comprising: encoding data to be transmitted to one or more second communication devices into one or more data streams; generating a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; mapping the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and transmitting the data unit on the plurality of tones according to the mapping of the data onto the different resource units.19. Second communication method of a second communication device configured to communicate with a first communication devices, the second communication method comprising: receiving a data unit including a preamble and a data field, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones; determining mapping information indicating if and how the mapping of the data of the one or more data streams onto different resource units within the data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and demapping the one or more data streams addressed to the second communication device from the received data unit according to the determined mapping information.20. A non-transitory computer-readable recording medium that stores therein a computer program product, which, when executed by a processor, causes the method according to embodiment 18 or 19 to be performed.21. A computer program comprising program code means for causing a computer to perform the steps of said method according to embodiment 18 or 19 when said computer pro-gram is carried out on a computer.

Claims

CLAIMS1. First communication device configured to communicate with one or more second communication devices, the first communication device comprising circuitry configured to: encode data to be transmitted to one or more second communication devices into one or more data streams; generate a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; map the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; transmit the data unit on the plurality of tones according to the mapping of the data onto the different resource units.

2. First communication device according to claim 1, wherein the circuitry is configured to change the mapping of the data of the one or more data streams onto different resource units within the data unit for multiple data symbols of the data unit or from one data symbol to another data symbol for all data symbols of the data unit.

3. First communication device according to claim 1, wherein the circuitry is configured to replicate one or more data streams and to map the one or more replicated data streams onto one or more other resource units than the data streams that have been replicated.

4. First communication device according to claim 1, wherein the circuitry is configured to change the mapping of the data of the one or more data streams onto different resource units within the data unit only for a first tone set covering a first number of tones of the plurality of tones and use a fixed mapping of the dataof the one or more data streams onto different resource units within the data unit for a second tone set covering the remaining number of tones of the plurality of tones.

5. First communication device according to claim 4, wherein the circuitry is configured to indicate the first tone set by resource unit indices indicating the resource units to which the first number of tones of the first tone set are allocated or by tone indices and / or tone intervals indicating the first number of tones of the first tone set.

6. First communication device according to claim 1 , wherein the circuitry is configured to apply predetermined, random- or rule-based changes of the mapping.

7. First communication device according to claim 1 , wherein the circuitry is configured to generate mapping information indicating if and how changes of the mapping have been applied.

8. First communication device according to claim 1 , wherein the circuitry is configured to generate mapping information including an indication of one or more of: the usage of changes of the mapping; resource unit allocation for one or more of the data symbols of the data unit, in particular of the resource unit allocation of the first data symbol of the data unit; a first tone set and / or resource unit set, for which changes of the mapping are applied; the way of changing the mapping, in particular if predetermined, random- or rulebased changes of the mapping are applied; one or more replicated data streams; one or more resource units carrying one or more replicated data streams; unallocated resource units; the application of changes of the mapping, in particular if the resource units all have equal size or different sizes, if there are resource units that are used for changingthe mapping and which are not used for changing the mapping, and / or if there are replicated resource units.

9. First communication device according to claim 7 or 8, wherein the circuitry is configured to include the mapping information into the preamble of the data unit, in particular into a signaling field of the preamble.

10. First communication device according to claim 1, wherein the circuitry is configured to change the mapping of the data onto different resource units without modifying the location of the pilot tones of the resource units.

11. First communication device according to claim 1 , wherein the circuitry is configured to encode the data to be transmitted to the one or more second communication devices into one or more data streams, each data stream carrying data from a different physical layer service data unit, PSDll, directed to a particular second communication device; and generate the data unit as physical layer protocol data unit, PPDll, including a data field carrying the data streams in the form of orthogonal frequency division multiplexing, OFDM, data symbols.

12. First communication device according to claim 1, wherein the circuitry is configured to fix the mapping of a first data symbol and change the mapping of subsequent data symbols by applying a circular shift to the resource unit allocation of a previous data symbol.

13. First communication device according to claim 1, wherein the circuitry is configured to transmit pilot tones for unallocated resources units that are subject to mapping changes, and / or to change the mapping between resource units having the same number of tones or between two resource units with a resource unit having double number of tones.

14. Second communication device configured to communicate with a first communication devices, the second communication device comprising circuitry configured to: receive a data unit including a preamble and a data field, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones; determine mapping information indicating if and how the mapping of the data of the one or more data streams onto different resource units within the data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and demap the one or more data streams addressed to the second communication device from the received data unit according to the determined mapping information.

15. Second communication device according to claim 14, wherein the circuitry is configured to determine the mapping information from a standard or a previous agreement with the first communication device or from signaling information included in the received data unit.

16. Second communication device according to claim 14, wherein the circuitry is configured to determine which different resource units contain data streams corresponding to replicated data streams and to combine the replicated data streams mapped onto said different resource units.

17. Second communication device according to claim 14, wherein the circuitry is configured to perform phase tracking based on pilot tones received from the resource units containing a data stream addressed to the second communication device and to include pilot tones from other resource units for which changes of the mapping have been applied.

18. First communication method of a first communication device configured to communicate with one or more second communication devices, the first communication method comprising: encoding data to be transmitted to one or more second communication devices into one or more data streams; generating a data unit from the data streams, the data unit including a preamble and a data field, the data field comprising a plurality of data symbols to be carried on a plurality of tones, each data symbol including data from the one or more data streams; mapping the data of the one or more data streams included in a data symbol onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones, wherein the mapping is changed within the data unit for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and transmitting the data unit on the plurality of tones according to the mapping of the data onto the different resource units.

19. Second communication method of a second communication device configured to communicate with a first communication devices, the second communication method comprising: receiving a data unit including a preamble and a data field, the data field comprising a plurality of data symbols carried on a plurality of tones, each data symbol including data from one or more data streams, wherein the data of the one or more data streams included in a data symbol are mapped onto different resource units to which the plurality of tones is allocated, each resource unit having a predetermined number of the plurality of tones; determining mapping information indicating if and how the mapping of the data of the one or more data streams onto different resource units within the data unit is changing for at least two data streams from at least one data symbol of the data unit to another data symbol of the data unit; and demapping the one or more data streams addressed to the second communication device from the received data unit according to the determined mapping information.

20. A non-transitory computer-readable recording medium that stores therein a computer program product, which, when executed by a processor, causes the method according to claim 18 or 19 to be performed.

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