Patent Publication Number: US-2023132900-A1

Title: Puncturing Pattern Based Control of OFDM Transmissions

Description:
TECHNICAL FIELD 
     The present invention relates to methods for controlling wireless transmissions and to corresponding devices, systems, and computer programs. 
     BACKGROUND 
     In wireless communication networks, it is known to utilize frequency division multiplexing to enable efficient sharing of a wireless medium. For example in the case of WLAN (Wireless Local Area Network) systems according to the IEEE 802.11 standards family, the IEEE 802.11ax technology introduces various enhancements to the Physical Layer (PHY) and Medium Access Control (MAC), including Orthogonal Frequency Division Multiple Access (OFDMA) based sharing of a carrier. Further, the IEEE 802.11ax technology supports preamble puncturing and Dual Carrier Modulation (DCM). Details of the IEEE 802.11ax technology are for example specified in IEEE P802.11ax™/D6.0 Draft Standard for Information technology— Telecommunications and information exchange between systems Local and metropolitan area networks—Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 1: Enhancements for High Efficiency WLAN (November 2019), in the following denoted as “IEEE 802.11ax Draft”. 
     In OFDMA the available bandwidth of the shared transmission medium is divided into different parts which are allocated to different users. In the IEEE 802.11ax technology these parts are referred to as “Resource Unit” (RU). Preamble puncturing refers to the possibility to mute one or more RUs if at the time of transmission it is determined that there are ongoing transmissions overlapping in the frequency domain with some RUs. These RUs are muted, and the remaining RUs may be transmitted.  FIG.  1    schematically illustrates an example of preamble puncturing in the IEEE 802.11ax technology. In this example, it is assumed that there are four users, allocated to different RUs, denoted as RU 1  to RU 4 . Further, it is assumed that high interference levels are detected in RU 3  and RU 4 . This may result in that a transmitter mutes RU 3  and RU 4  and proceeds to transmit in RU 1  and RU 2 . Preamble puncturing may help to improve efficiency of using of the shared wireless medium. In preamble puncturing as specified in the IEEE 802.11x Draft, either all the subcarriers allocated to one user are transmitted or all subcarriers allocated to one user are muted. In this respect, it is also noted that In preamble puncturing as specified in the IEEE 802.11x Draft not only the preamble but also the data of the wireless transmission are muted. Accordingly, also the preamble puncturing could also more generically be considered as puncturing of RUs. 
     DCM is a modulation technique intended to enhance the robustness of wireless transmissions. With DCM the same user code bits are modulated onto a pairs of subcarriers in order to increase the received SNR (Signal-to-Noise Ratio) through gains in power and frequency diversity. The IEEE 802.11ax technology supports DCM in both Single User (SU) and MultiUser (MU) modes. In either case, a given user is allocated one RU comprising N subcarriers, and bit sequences are mapped to a pair of symbols (d k ,d q ( k )) where k is a subcarrier index in the range 0≤k&lt;N/2 and q(k) is in the range N/2≤q(k)&lt;N, see section 27.3.12.9 of the IEEE 8021.11ax draft.  FIG.  2    schematically illustrates a corresponding example assuming that DCM is applied for a user, using OFDM (Orthogonal Frequency Division Multiplexing) modulation in an RU, which is allocated to the user and denoted as RU M . In accordance with the IEEE 802.11ax draft, DCM involves that a symbol of user data is modulated onto subcarriers with index k and that the same symbol is modulated onto subcarriers with index q(k)=k+ N/2. 
     Further, an enhancement of the WLAN technology according to the IEEE 802.11 standards family, denoted as EHT (Extremely High Throughput), proposes to increase the channel bandwidth to 320 MHz, as well as introduce support for multi-link operation. With multi-link operation, the total aggregated bandwidth using several channels could exceed 1 GHz. Since the bandwidth allocated to a single user can be very large, and as a consequence the probability of a user experiencing interference increases. The interference can be either static or intermittent. In the static case the interference arises from external sources, such as radars or fixed microwave links, which may occupy a bandwidth portion for long time periods and have priority over WLANs. In these cases the interference may be avoided by the transmitter since it can refrain from transmitting any information in the interfered bandwidth portions. In the intermittent case, the interference arises from other WLANs, and the transmitter may detect the interference just prior to transmission. If this happens, it may not have time to reformat the transmission to avoid sending information in the interfered bandwidth portion. For example, if many stations in overlapping BSSs (BSS: basic service set) are sharing the medium, the probability of intermittent, high interference levels in some bandwidth parts is not negligible. In view of this situation, “Preamble Puncturing and RU Aggregation″, Internet document IEEE 802.11-19/1869r0 (URL:”https://mentor.ieee.org/802.11/dcn/19/11-19-1869-00-00be-preamble-puncturing-and-ru-aggregation.pptx”, November 2019) proposes to introduce the possibility to assign more than one RU to a single user. Further, “Multi-RU Support”, Internet document IEEE 802.11-19/1908r0 (URL: “https://mentor.ieee.org/802.11/dcn/19/11-19-1908-00-00be-multi-ru-support.pptx”, November 2019) proposes to allow preamble puncturing for only a subset of the RUs assigned to a single user. In particular, it is proposed to introduce a new transmitter block denoted as RU parser, which distributes encoded data bits of a user to multiple RUs. In case intermittent interference is detected, it is possible to puncture one or more RUs, and if the channel code is strong enough, it is still possible for the receiver to decode the data. 
     When preamble puncturing is applied to a SU transmission as proposed above, as much as 50% of the code bits may be punctured. Since the lowest code rate specified for the IEEE 802.11 standards family is 1/2, the EHT technology may require new codes with lower rate to support puncturing of SU transmissions, in case of intermittent interference. Further, DCM as specified in the IEEE 802.11ax Draft is not designed for multi-RU transmissions. 
     Accordingly, there is a need for techniques which allow for redundantly utilizing multiple subcarriers when performing OFDM based wireless transmissions that may be subject to puncturing in the presence of intermittent interference. 
     SUMMARY 
     According to an embodiment, a method of controlling wireless transmissions in a wireless communication system is provided. According to the method, a wireless transmitter transmits user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Based on a mapping of the user data to the RUs, the wireless transmitter modulates a symbol of the user data onto a first set of subcarriers of a first RU of the RUs and redundantly modulates the symbol onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs. 
     According to a further embodiment, a method of controlling wireless transmissions in a wireless communication system is provided. According to the method, a wireless receiver receives user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Based on a mapping of the user data to the RUs, the wireless receiver demodulates a symbol of the user data from a first set of subcarriers of a first RU of the RUs and redundantly demodulates the symbol from a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs. 
     According to a further embodiment, a wireless transmitter for a wireless communication system is provided. The wireless transmitter is configured to transmit user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, the wireless transmitter is configured to, based on a mapping of the user data to the RUs, modulate a symbol of the user data onto a first set of subcarriers of a first resource unit of the RUs and redundantly modulate the symbol onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs. 
     According to a further embodiment, a wireless transmitter for a wireless communication system is provided. The wireless transmitter comprises at least one processor and a memory. The memory contains instructions executable by said at least one processor, whereby the wireless transmitter is operative to transmit user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, the memory contains instructions executable by said at least one processor, whereby the wireless transmitter is operative to, based on a mapping of the user data to the RUs, modulate a symbol of the user data onto a first set of subcarriers of a first resource unit of the RUs and redundantly modulate the symbol onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs. 
     According to a further embodiment, a wireless receiver for a wireless communication system is provided. The wireless receiver is configured to receive user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, the wireless receiver is configured to, based on a mapping of the user data to the RUs, demodulate a symbol of the user data from a first set of subcarriers of a first RU of the RUs and redundantly demodulate the symbol from a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the resource RUs. 
     According to a further embodiment, a wireless transmitter for a wireless communication system is provided. The wireless transmitter comprises at least one processor and a memory. The memory contains instructions executable by said at least one processor, whereby the wireless transmitter is operative to receive user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, the memory contains instructions executable by said at least one processor, whereby the wireless transmitter is operative to, based on a mapping of the user data to the RUs, demodulate a symbol of the user data from a first set of subcarriers of a first RU of the RUs and redundantly demodulate the symbol from a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the resource RUs. 
     According to a further embodiment of the invention, a computer program or computer program product is provided, e.g., in the form of a non-transitory storage medium, which comprises program code to be executed by at least one processor of a wireless transmitter. Execution of the program code causes the wireless transmitter to transmit user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, execution of the program code causes the wireless transmitter to, based on a mapping of the user data to the RUs, modulate a symbol of the user data onto a first set of subcarriers of a first resource unit of the RUs and redundantly modulate the symbol onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs. 
     According to a further embodiment of the invention, a computer program or computer program product is provided, e.g., in the form of a non-transitory storage medium, which comprises program code to be executed by at least one processor of a wireless receiver. Execution of the program code causes the wireless receiver to receive user data using OFDM modulation on a shared wireless medium having a bandwidth organized in multiple RUs. Further, execution of the program code causes the wireless receiver to, based on a mapping of the user data to the RUs, demodulate a symbol of the user data from a first set of subcarriers of a first RU of the RUs and redundantly demodulate the symbol from a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the resource RUs 
     Details of such embodiments and further embodiments will be apparent from the following detailed description of embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    schematically illustrates an example of preamble puncturing. 
         FIG.  2    schematically illustrates an example of DCM. 
         FIG.  3    schematically illustrates a wireless communication system according to an embodiment. 
         FIG.  4    schematically illustrates a transmitter architecture according to an embodiment. 
         FIG.  5    schematically illustrates a receiver architecture according to an embodiment. 
         FIG.  6    schematically illustrates an example of allowed puncturing patterns. 
         FIG.  7    schematically illustrates an example of multi-RU DCM according to an embodiment. 
         FIG.  8    schematically illustrates a further example of multi-RU DCM according to an embodiment. 
         FIG.  9    schematically illustrates an example of processes according to an embodiment. 
         FIG.  10    shows a flowchart for schematically illustrating a method according to an embodiment. 
         FIG.  11    shows a block diagram for schematically illustrating functionalities of a wireless transmitter according to an embodiment. 
         FIG.  12    shows a flowchart for schematically illustrating a further method according to a further embodiment. 
         FIG.  13    shows a block diagram for schematically illustrating a wireless receiver according to an embodiment. 
         FIG.  14    schematically illustrates structures of a wireless transmitter according to an embodiment. 
         FIG.  15    schematically illustrates structures of a wireless receiver according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, concepts in accordance with exemplary embodiments of the invention will be explained in more detail and with reference to the accompanying drawings. The illustrated embodiments relate to controlling of OFDM based wireless transmissions in a wireless communication system. The wireless communication system may be a WLAN (Wireless Local Area Network) system based on a IEEE 802.11 technology, i.e., according to the IEEE 802.11 standards family. However, it is noted that the illustrated concepts could also be applied to other wireless communication technologies, e.g., to the LTE (Long Term Evolution) or NR (New Radio) technology specified by 3GPP (3 rd  Generation Partnership Project). The wireless transmissions are from a wireless transmitter to a wireless receiver. By way of example, the wireless transmitter could be an access point (AP) of the wireless communication system and the wireless receiver a station (STA) associated with the AP. Alternatively, the wireless receiver could be an AP of the wireless communication system and the wireless transmitter a STA associated with the AP. In some scenarios, the same device could act both as a wireless transmitter a wireless receiver, e.g., an AP or STA engaged in bidirectional wireless transmissions. 
       FIG.  3    illustrates an exemplary wireless communication system according to an embodiment. In the illustrated example, the wireless communication system includes multiple APs  10 , in the illustrated example referred to as AP 1 , AP 2 , AP 3 , and multiple stations (STAs)  11 , in the illustrated example referred to as STA 11 , STA 21 , STA 22 , and STA 31 . The station STA 11  is served by AP 1  (in a first BSS denoted as BSS1), the stations STA 21  and STA 22  are served by AP 2  (in a second BSS denoted as BSS2). The station STA 31  is served by AP 3  (in a third BSS denoted as BSS3). The stations  11  may correspond to various kinds of wireless devices, for example user terminals, such as mobile or stationary computing devices like smartphones, laptop computers, desktop computers, tablet computers, gaming devices, or the like. Further, the stations  11  could for example correspond to other kinds of equipment like smart home devices, printers, multimedia devices, data storage devices, or the like. Each AP  10  may operate as a wireless transmitter, in the case of downlink (DL) transmissions from the AP  10  to a station  11 , and/or as a wireless receiver, in the case of uplink (UL) transmissions from the station  11  to the AP  10 . Similarly, station  11  may operate as a wireless transmitter, in the case of UL transmissions from the station to an AP  10 , and/or as a wireless receiver, in the case of DL transmissions from an AP  10  to the station  11 . 
     In the example of  FIG.  3   , each of the stations  11  may connect through a radio link to one of the APs  10 . For example depending on location or channel conditions experienced by a given station  11 , the station  11  may select an appropriate AP  10  and BSS for establishing the radio link. The radio link may be based on one or more OFDM carriers from a frequency spectrum which is shared on the basis of a contention based mechanism, e.g., an unlicensed band like the 2.4 GHz ISM band, the 5 GHz band, the 6 GHz band, or the 60 GHz band. 
     Each AP  10  may provide data connectivity of the stations  11  connected to the AP  10 . As further illustrated, the APs  10  may be connected to a data network (DN)  110 . In this way, the APs  10  may also provide data connectivity of stations  11  connected to different APs  10 . Further, the APs  10  may also provide data connectivity of the stations  11  to other entities, e.g., to one or more servers, service providers, data sources, data sinks, user terminals, or the like. Accordingly, the radio link established between a given station  11  and its serving AP  10  may be used for providing various kinds of services to the station  11 , e.g., a voice service, a multimedia service, or other data service. Such services may be based on applications which are executed on the station  11  and/or on a device linked to the station  11 . By way of example,  FIG.  3    illustrates an application service platform  150  provided in the DN  110 . The application(s) executed on the station  11  and/or on one or more other devices linked to the station  11  may use the radio link for data communication with one or more other stations  11  and/or the application service platform  150 , thereby enabling utilization of the corresponding service(s) at the station  11 . 
     In the illustrated concepts, it is assumed that OFDM modulation is utilized for transmissions on a shared wireless medium. A bandwidth of the wireless medium, e.g., in the range of 20 MHz to 320 MHz, is organized in multiple RUs. Each of the RUs includes multiple subcarriers which can be used in the OFDM modulation. The RUs can be allocated to different users. However, in some situations the entire bandwidth, i.e., all RUs, could also be allocated to a single user. For example, the allocation of the bandwidth could be dynamically or semi-statically changed between configurations where the RUs are allocated to two or more different users, and configurations where the RUs are allocated to a single user. 
     Based on the OFDM modulation, user data is transmitted from a wireless transmitter to a wireless receiver. For transmitting the user data, the user data may first be encoded, e.g., using an LDPC (Low Density Parity Check Code), to generate a stream or sequence of bits, which is mapped to a first RU and to a second RU. For transmitting the user data, a symbol of the user data is modulated onto a first set of subcarriers of the first RU and redundantly modulated onto a second set of subcarriers of the second RU. The mapping of the user data to the RUs, i.e., the selection of the first RU and the second RU among the available RUs, is based on possible puncturing patterns applied to the RUs. The puncturing patterns may be applied by the wireless transmitter to mute certain RUs in response to detecting intermittent interference. Accordingly, the transmission of the user data may utilize DCM, with two copies of code bits generated by DCM being mapped to different RUs. The mapping of user data to the RUs is determined in such a way that, in case of puncturing the RUs, at least one of the copies will not be punctured. In this way, gains from DCM can be used to effectively support preamble puncturing. 
       FIG.  4    schematically illustrates an example architecture of a wireless transmitter, which may be used for implementing the illustrated concepts, e.g., in any of the above-mentioned APs  10  or stations  11 . In the example of  FIG.  4   , the wireless transmitter includes a PHY (Physical layer) entity  410 , and a MAC entity  420 . The MAC entity  420  provides a PSDU (PHY Service Data Unit)  430  to the PHY entity  410 . The PHY entity  410  includes an encoder  411  and a mapper  412 . The encoder  411  encodes the PSDU  430  provided by the MAC entity  430 , e.g., based on an LDPC code. The mapper  412  maps the code bits provided by the encoder  411  to RUs for modulation of symbols onto subcarriers of the RUs. The operation of the mapper  412  in particular involves mapping of a sequence of code bits to a first set of subcarriers in a first one of the RUs, and mapping a copy of the sequence of code bits to a second set of subcarriers in a second one of the RUs. The sequence of code bits is thus redundantly modulated onto the first set of subcarriers and onto the second set of subcarriers, with the first and second set of subcarriers being in different RUs. The operation of the mapper  412  thus enables DCM using multiple RUs, in the following also referred to as multi-RU DCM. The mapping of the code bits to RUs as applied by the mapper  412  is based on possible puncturing patterns  413 , which may be applied to the RUs. For example, the possible puncturing patterns  413  could be preconfigured in the wireless transmitter, e.g., by storing a set of allowed puncturing patterns or a set of forbidden puncturing patterns in a memory of the wireless transmitter. 
       FIG.  5    schematically illustrates an example architecture of a wireless receiver, which may be used for implementing the illustrated concepts, e.g., in any of the above-mentioned APs  10  or stations  11 . In the example of  FIG.  5   , the wireless receiver includes a PHY entity  510 , and a MAC entity  520 . The PHY entity  410  includes a demapper  511  and a decoder  512 . The demapper  511  demaps the code bits corresponding to symbols demodulated from subcarriers of the RUs. The operation of the demapper  511  in particular involves demapping of a sequence of code bits corresponding to a symbol demodulated from a first set of subcarriers in a first one of the RUs, and demapping a copy of the sequence of code bits corresponding to a symbol demodulated from a second set of subcarriers in a second one of the RUs. In other words, the demapper  511  indentifies that the symbol demodulated from the first set of subcarriers and the symbol demodulated from the second set of subcarriers relate to the same sequence of code bits. The sequence of code bits is thus redundantly demodulated from the first set of subcarriers and from the second set of subcarriers, with the first and second set of subcarriers being in different RUs. The decoder  512  then decodes the redundantly demodulated code bits, e.g., based on an LDPC code. Various methods may be applied for combining the redundantly demodulated symbols. The PHY entity  510  then generates a PSDU  530  from the decoded bits and provides the PSDU to the MAC entity  520 . The operation of the demapper  511  thus enables DCM using multiple RUs, i.e., multi-RU DCM, at the receiver side. The mapping of the code bits to RUs as applied by the demapper  511  is based on possible puncturing patterns  513 , which may be applied to the RUs. For example, the possible puncturing patterns  513  could be preconfigured in the wireless receiver, e.g., by storing a set of allowed puncturing patterns or a set of forbidden puncturing patterns in a memory of the wireless transmitter. 
       FIG.  6    illustrates an example of allowed puncturing patterns, which constitute a subset of possible puncturing patterns. Puncturing patterns differing from the allowed puncturing patterns may be considered as forbidden. By such limitation to a set of allowed puncturing patterns, complexity issues, arising for example from the need to signal which RUs have been punctured, may be avoided. In the example of  FIG.  6   , it is assumed that the available OFDM bandwidth is separated into four RUs having the same bandwidth, e.g., 20 MHz. The RUs are denoted by RU 1 , RU 2 , RU 3 , and RU 4 . The RUs indicated by dashed lines are allowed to be punctured. 
     When considering that at most 50% of the total bandwidth is allowed to be punctured, it is always possible to configure the mapping to the RUs in such a way that one full copy of the code bits is mapped to non-punctured RUs. This task may be further simplified if some of the possible puncturing patterns are forbidden, e.g., by specifying a set of allowed puncturing patterns like in the example of  FIG.  6    or by specifying a set of forbidden puncturing patterns. 
       FIG.  7    schematically illustrates an example of multi-RU DCM based on the illustrated concepts. The example of  FIG.  7    assumes that the available OFDM bandwidth is separated into four RUs having the same bandwidth, e.g., 20 MHz. The RUs are denoted by RU 1 , RU 2 , RU 3 , and RU 4 . The allowed puncturing patterns may correspond to those as shown in  FIG.  6   . In the illustrated example, the full set of code bits is mapped to RU 1  and RU 4  while DCM is used to repeat, i.e., redundantly modulate, the code bits in RU 2  and RU 3 . In this way, it can be ensured that the receiver will get at least one full copy of the code bits, irrespective of whether puncturing is utilized and which puncturing pattern is applied. In the example of  FIG.  7   , k denotes an index of the subcarriers in RU 1 , while m denotes an index of the subcarriers in RU 4 . As illustrated, the multi-RU DCM modulates code bits onto a set of subcarriers with index k in RU 1 , and generates one copy of the code bits which are modulated onto a set of subcarriers with q(k) in RU 2 . Here, q(k) may be equal to k. Similarly, the multi-RU DCM the multi-RU DCM modulates code bits onto a set of subcarriers with index m in RU 4 , and generates one copy of the code bits which are modulated onto a set of subcarriers with index q(m) in RU 3 . Here, q(m) may be equal to m. 
       FIG.  8    schematically illustrates a further example of multi-RU DCM based on the illustrated concepts. Similar to the example of  FIG.  7   , the example of  FIG.  8    assumes that the available OFDM bandwidth is separated into four RUs having the same bandwidth, e.g., 20 MHz. The RUs are denoted by RU 1 , RU 2 , RU 3 , and RU 4 . The allowed puncturing patterns may correspond to those as shown in  FIG.  6   . Also in the example of  FIG.  8   , the full set of code bits is mapped to RU 1  and RU 4  while DCM is used to repeat, i.e., redundantly modulate, the code bits in RU 2  and RU 3 . In the example of  FIG.  8   , k denotes an index of the subcarriers in RU 1 , while m denotes an index of the subcarriers in RU 4 . As illustrated, the multi-RU DCM modulates code bits onto a set of subcarriers with index k in RU 1 , and generates one copy of the code bits which are modulated onto a set of subcarriers with index q(k) in RU 3 . Here, q(k) may be equal to k. Similarly, the multi-RU DCM the multi-RU DCM modulates code bits onto a set of subcarriers with index m in RU 4 , and generates one copy of the code bits which are modulated onto a set of subcarriers with index q(m) in RU 2 . Here, q(m) may be equal to m. In the example of  FIG.  8   , the RUs to which the copies of the code bits are mapped are non-adjacent, i.e., there is at least one other RU between these RUs. Accordingly, the distance in the frequency domain between copies of the code bits can be increased as compared to the example of  FIG.  7   , which may yield larger diversity gains in the absence of puncturing. 
       FIG.  9    schematically illustrates an example of processes which are based on the above-described concepts. The processes of  FIG.  9    involve an AP  10 , e.g., corresponding to any of the above-mentioned Aps  10 , and a STA  11 , e.g., corresponding to any of the above-mentioned STAs  11 . 
     As illustrated, in the processes of  FIG.  9    the AP  10  may receive configuration data  901 . The configuration data  901  may dynamically or semi-statically configure the AP  10  with information indicating allowed puncturing patterns, e.g., as illustrated in  FIG.  6   . Alternatively or in addition, the configuration data  901  may dynamically or semi-statically configure the AP  10  with information indicating forbidden puncturing patterns. However, it is noted that reception of the configuration data  901  is optional and that at least a part of such information indicating allowed puncturing patterns or forbidden puncturing patterns could also be preconfigured in the AP  10 . 
     Further, the STA  11  may receive configuration data  902 . The configuration data  902  may dynamically or semi-statically configure the STA  11  with information indicating allowed puncturing patterns, e.g., as illustrated in  FIG.  6   . Alternatively or in addition, the configuration data  902  may dynamically or semi-statically configure the STA  11  with information indicating forbidden puncturing patterns. However, it is noted that reception of the configuration data  902  is optional and that at least a part of such information indicating allowed puncturing patterns or forbidden puncturing patterns could also be preconfigured in the STA  11 . 
     As further illustrated, the AP  10  transmits a wireless transmission  903  to the STA  11 . The wireless transmission  903  transmits user data using OFDM modulation on the shared wireless medium, which is organized in multiple RUs. This involves that, based on a mapping of the user data to the resource units, the AP  10  modulates symbols of the user data onto a first set of subcarriers of a first RU of the RUs and redundantly modulates the symbols onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs, such as the above-mentioned allowed or forbidden puncturing patterns. 
     Based on the mapping of the user data to the resource units, the STA  11  may then demodulate the symbols of the user data of the wireless transmission  903  from the first set of subcarriers and redundantly demodulates the symbol from the second set of subcarriers. 
     As further illustrated, the STA  10  transmits a wireless transmission  904  to the AP  10 . The wireless transmission  904  transmits user data using OFDM modulation on the shared wireless medium, which is organized in multiple RUs. This involves that, based on a mapping of the user data to the resource units, the STA  11  modulates symbols of the user data onto a first set of subcarriers of a first RU of the RUs and redundantly modulates the symbols onto a second set of subcarriers of a second RU of the RUs. The mapping of the user data to the RUs is based on possible puncturing patterns applied to the RUs, such as the above-mentioned allowed or forbidden puncturing patterns. 
     Based on the mapping of the user data to the resource units, the AP  10  demodulates the symbol of the user data of the wireless transmission  904  from the first set of subcarriers and redundantly demodulates the symbol from the second set of subcarriers. 
     As can be seen, in the example of  FIG.  9    the AP  10  acts as a wireless transmitter for the wireless transmission  903 , and the STA  11  acts as a wireless receiver for the wireless transmission  903 . For the wireless transmission  904 , the STA  11  acts as a wireless transmitter and the AP  10  acts as a wireless receiver. It is noted that in variants of the processes either the wireless transmission  903  or the wireless transmission  904  could be omitted. 
       FIG.  10    shows a flowchart for illustrating a method, which may be utilized for implementing the illustrated concepts. The method of  FIG.  10    may be used for implementing the illustrated concepts in a wireless transmitter for operation in a wireless communication system. The wireless communication system may be based on a wireless local area network, WLAN, technology, e.g., according to the IEEE 802.11 standards family. The wireless transmitter may for example correspond to or be part of any of the above APs  10 . Alternatively, the wireless transmitter could for example correspond to or be part of any of the above stations  11 . In the method of  FIG.  10   , it assumed that a shared wireless medium, e.g., a carrier from an unlicensed frequency spectrum, is utilized for wireless transmissions based on OFDM modulation. A bandwidth of the shared wireless medium is organized in multiple RUs. The multiple RUs can be allocated to different users, and OFDMA could be used for sharing the wireless medium. However, in some scenarios the RUs could also be allocated to a single user. 
     If a processor-based implementation of the wireless transmitter is used, at least some of the steps of the method of  FIG.  10    may be performed and/or controlled by one or more processors of the wireless transmitter. Such wireless transmitter may also include a memory storing program code for implementing at least some of the below described functionalities or steps of the method of  FIG.  10   . 
     At step  1010 , the wireless transmitter may determine possible puncturing patterns. The puncturing patterns may be applied by the wireless transmitter to mute certain RUs in response to detecting intermittent interference. This may for example be based on information indicating allowed puncturing patterns, e.g., as illustrated in  FIG.  6   . At least a part of the information indicating the allowed puncturing patterns can be preconfigured in the wireless transmitter. Alternatively or in addition at least a part of the information indicating the allowed puncturing patterns could be dynamically or semi-statically configured by configuration data provided to the wireless transmitter. Alternatively or in addition, the wireless transmitter may determine the possible puncturing patterns based on information indicating forbidden puncturing patterns. At least a part of the information indicating the forbidden puncturing patterns can be preconfigured in the wireless transmitter. Alternatively or in addition at least a part of the information indicating the forbidden puncturing patterns could be dynamically or semi-statically configured by configuration data provided to the wireless transmitter. 
     At step  1020 , the wireless transmitter may determine interference levels on the RUs. This may involve that the wireless transmitter performs measurements on the RUs and/or receives information on interference levels on the RUs. 
     At step  1030 , the wireless transmitter may determine a mapping of user data to the RUs. The mapping is based on possible puncturing patterns applied to the RUs, e.g., as determined at step  1010 . Further, the mapping may be based on interference levels on the RUs, e.g., as determined at step  1020 . By considering the interference levels, it can be taken into account that RUs with high interference level, e.g., with an interference level above a certain threshold have a higher likelihood of being subject to puncturing. 
     Accordingly, the method may utilize a mapping of the user data to the RUs, which is based on possible puncturing patterns applied to the RUs, in particular on allowed puncturing patterns and/or forbidden puncturing patterns. Further, the mapping may be based on interference levels on the RUs. 
     At step  1040 , the wireless transmitter transmits the user data on the wireless medium, using OFDM modulation. This involves modulating the user data onto subcarriers of the shared medium in accordance with step  1050 . 
     At step  1050 , the wireless transmitter modulates a symbol of the user data onto a first set of subcarriers of a first RU of the RUs and redundantly modulates the symbol onto a second set of subcarriers of a second RU of the RUs, e.g., based on DCM. This is accomplished based on the above mapping of the user data to the RUs. In particular, the mapping determines selection of the first RU and the second RU. The mapping of the user data to the RUs may be configured to prevent that both the first RU and the second RU are subject to puncturing. 
       FIG.  11    shows a block diagram for illustrating functionalities of an wireless transmitter  1100  which operates according to the method of  FIG.  10   . The wireless transmitter  1100  may for example correspond to one of above-mentioned APs  10  or stations  11 . As illustrated, the wireless transmitter  1100  may optionally be provided with a module  1110  configured to determine possible puncturing patterns, such as explained in connection with step  1010 . Further, the wireless transmitter  1100  may optionally be provided with a module  1120  configured to determine interference levels, such as explained in connection with step  1020 . Further, the wireless transmitter  1100  may optionally be provided with a module  1130  configured to determine a mapping of user data to RUs, such as explained in connection with step  1030 . Further, the wireless transmitter  1100  may be provided with a module  1140  configured to transmit user data, such as explained in connection with step  1040 . Further, the wireless transmitter  1100  may be provided with a module  1150  configured to modulate a symbol of the user data to a first set of subcarriers and to a second set of subcarriers, such as explained in connection with step  1050 . 
     It is noted that the wireless transmitter  1100  may include further modules for implementing other functionalities, such as known functionalities of WLAN AP or WLAN station. Further, it is noted that the modules of the wireless transmitter  1100  do not necessarily represent a hardware structure of the wireless transmitter  1100 , but may also correspond to functional elements, e.g., implemented by hardware, software, or a combination thereof. 
       FIG.  12    shows a flowchart for illustrating a method, which may be utilized for implementing the illustrated concepts. The method of  FIG.  12    may be used for implementing the illustrated concepts in a wireless receiver for operation in a wireless communication system. The wireless communication system may be based on a wireless local area network, WLAN, technology, e.g., according to the IEEE 802.11 standards family. The wireless receiver may for example correspond to or be part of any of the above APs  10 . Alternatively, the wireless receiver could for example correspond to or be part of any of the above stations  11 . In the method of  FIG.  12   , it assumed that a shared wireless medium, e.g., a carrier from an unlicensed frequency spectrum, is utilized for wireless transmissions based on OFDM modulation. A bandwidth of the shared wireless medium is organized in multiple RUs. The multiple RUs can be allocated to different users, and OFDMA could be used for sharing the wireless medium. However, in some scenarios the RUs could also be allocated to a single user. 
     If a processor-based implementation of the wireless receiver is used, at least some of the steps of the method of  FIG.  12    may be performed and/or controlled by one or more processors of the wireless receiver. Such wireless receiver may also include a memory storing program code for implementing at least some of the below described functionalities or steps of the method of  FIG.  12   . 
     At step  1210 , the wireless receiver may determine possible puncturing patterns. This may for example be based on information indicating allowed puncturing patterns, e.g., as illustrated in  FIG.  6   . At least a part of the information indicating the allowed puncturing patterns can be preconfigured in the wireless receiver. Alternatively or in addition at least a part of the information indicating the allowed puncturing patterns could be dynamically or semi-statically configured by configuration data provided to the wireless receiver. Alternatively or in addition, the wireless receiver may determine the possible puncturing patterns based on information indicating forbidden puncturing patterns. At least a part of the information indicating the forbidden puncturing patterns can be preconfigured in the wireless receiver. Alternatively or in addition at least a part of the information indicating the forbidden puncturing patterns could be dynamically or semi-statically configured by configuration data provided to the wireless receiver. 
     At step  1220 , the wireless receiver may determine interference levels on the RUs. This may involve that the wireless receiver performs measurements on the RUs and/or receives information on interference levels on the RUs. 
     At step  1230 , the wireless receiver may determine a mapping of user data to the RUs. The mapping is based on possible puncturing patterns applied to the RUs, e.g., as determined at step  1210 . Further, the mapping may be based on interference levels on the RUs, e.g., as determined at step  1220 . By considering the interference levels, it can be taken into account that RUs with high interference level, e.g., with an interference level above a certain threshold have a higher likelihood of being subject to puncturing. 
     Accordingly, the method may utilize a mapping of the user data to the RUs, which is based on possible puncturing patterns applied to the RUs, in particular on allowed puncturing patterns and/or forbidden puncturing patterns. Further, the mapping may be based on interference levels on the RUs. 
     At step  1240 , the wireless transmitter receives the user data from the wireless medium, using OFDM modulation. This involves demodulating the user data from subcarriers of the shared medium in accordance with step  1250 . 
     At step  1250 , the wireless receiver demodulates a symbol of the user data from a first set of subcarriers of a first RU of the RUs and redundantly demodulates the symbol from a second set of subcarriers of a second RU of the RUs, e.g., based on DCM. This is accomplished based on the above mapping of the user data to the RUs. In particular, the mapping determines selection of the first RU and the second RU. The mapping of the user data to the RUs may be configured to prevent that both the first RU and the second RU are subject to puncturing. 
       FIG.  13    shows a block diagram for illustrating functionalities of an wireless receiver  1300  which operates according to the method of  FIG.  12   . The wireless receiver  1300  may for example correspond to one of above-mentioned APs  10  or stations  11 . As illustrated, the wireless receiver  1300  may optionally be provided with a module  1310  configured to determine possible puncturing patterns, such as explained in connection with step  1210 . Further, the wireless receiver  1300  may optionally be provided with a module  1320  configured to determine interference levels, such as explained in connection with step  1220 . Further, the wireless receiver  1300  may optionally be provided with a module  1330  configured to determine a mapping of user data to RUs, such as explained in connection with step  1230 . Further, the wireless receiver  1300  may be provided with a module  1340  configured to receive user data, such as explained in connection with step  1240 . Further, the wireless receiver  1300  may be provided with a module  1350  configured to demodulate a symbol of the user data from a first set of subcarriers and from a second set of subcarriers, such as explained in connection with step  1250 . 
     It is noted that the wireless receiver  1300  may include further modules for implementing other functionalities, such as known functionalities of WLAN AP or WLAN station. Further, it is noted that the modules of the wireless receiver  1300  do not necessarily represent a hardware structure of the wireless receiver  1300 , but may also correspond to functional elements, e.g., implemented by hardware, software, or a combination thereof. 
     It is noted that the functionalities as described in connection with  FIGS.  10  to  13    could also be combined. For example, the same AP could operate as a wireless transmitter according to the method of  FIG.  10    and as a wireless receiver according to the method of  FIG.  12   . Similarly, the same station could operate as a wireless transmitter according to the method of  FIG.  10    and as a wireless receiver according to the method of  FIG.  12   . Further, the functionalities as described in connection with  FIGS.  10  to  13    could also be combined in a system including a wireless transmitter operating according to the method of  FIG.  10    and a wireless receiver operating according to the method of  FIG.  12   . 
       FIG.  14    illustrates a processor-based implementation of a wireless transmitter  1400  which may be used for implementing the above-described concepts. For example, the structures as illustrated in  FIG.  14    may be used for implementing the concepts in any of the above-mentioned APs  10  or stations  11 . 
     As illustrated, the wireless transmitter  1400  includes one or more radio interfaces  1410 . The radio interface(s)  1410  may for example be based on a WLAN technology, e.g., according to an IEEE 802.11 family standard. However, other wireless technologies could be supported as well, e.g., the LTE technology or the NR technology. The radio interface(s)  1410  may be based on multiple antennas of the wireless transmitter  1400 . 
     Further, the wireless transmitter  1400  may include one or more processors  1450  coupled to the radio interface(s)  1410  and a memory  1460  coupled to the processor(s)  1450 . By way of example, the radio interface(s)  1410 , the processor(s)  1450 , and the memory  1460  could be coupled by one or more internal bus systems of the access point  1400 . The memory  1460  may include a Read-Only-Memory (ROM), e.g., a flash ROM, a Random Access Memory (RAM), e.g., a Dynamic RAM (DRAM) or Static RAM (SRAM), a mass storage, e.g., a hard disk or solid state disk, or the like. As illustrated, the memory  1460  may include software  1470  and/or firmware  1480 . The memory  1460  may include suitably configured program code to be executed by the processor(s)  1450  so as to implement the above-described functionalities for controlling wireless transmissions, such as explained in connection with  FIGS.  10  and  11   . 
     It is to be understood that the structures as illustrated in  FIG.  14    are merely schematic and that the wireless transmitter  1400  may actually include further components which, for the sake of clarity, have not been illustrated, e.g., further interfaces or further processors. Also, it is to be understood that the memory  1460  may include further program code for implementing known functionalities of a WLAN AP or WLAN station. According to some embodiments, also a computer program may be provided for implementing functionalities of the wireless transmitter  1400 , e.g., in the form of a physical medium storing the program code and/or other data to be stored in the memory  1460  or by making the program code available for download or by streaming. 
       FIG.  15    illustrates a processor-based implementation of a wireless receiver  1500  which may be used for implementing the above-described concepts. For example, the structures as illustrated in  FIG.  15    may be used for implementing the concepts in any of the above-mentioned APs  10  or stations  11 . 
     As illustrated, the wireless receiver  1500  includes one or more radio interfaces  1510 . The radio interface(s)  1510  may for example be based on a WLAN technology, e.g., according to an IEEE 802.11 family standard. However, other wireless technologies could be supported as well, e.g., the LTE technology or the NR technology. The radio interface(s)  1510  may be based on multiple antennas of the wireless receiver  1500 . 
     Further, the wireless receiver  1500  may include one or more processors  1550  coupled to the radio interface(s)  1510  and a memory  1560  coupled to the processor(s)  1550 . By way of example, the radio interface(s)  1510 , the processor(s)  1550 , and the memory  1560  could be coupled by one or more internal bus systems of the access point  1500 . The memory  1560  may include a ROM, e.g., a flash ROM, a RAM, e.g., a DRAM or SRAM, a mass storage, e.g., a hard disk or solid state disk, or the like. As illustrated, the memory  1560  may include software  1570  and/or firmware  1580 . The memory  1560  may include suitably configured program code to be executed by the processor(s)  1550  so as to implement the above-described functionalities for controlling wireless transmissions, such as explained in connection with  FIGS.  12  and  13   . 
     It is to be understood that the structures as illustrated in  FIG.  15    are merely schematic and that the wireless receiver  1500  may actually include further components which, for the sake of clarity, have not been illustrated, e.g., further interfaces or further processors. Also, it is to be understood that the memory  1560  may include further program code for implementing known functionalities of a WLAN AP or WLAN station. According to some embodiments, also a computer program may be provided for implementing functionalities of the wireless receiver  1500 , e.g., in the form of a physical medium storing the program code and/or other data to be stored in the memory  1560  or by making the program code available for download or by streaming. 
     As can be seen, the concepts as described above may be used for efficiently controlling OFDM based wireless transmissions with redundant utilization of multiple carriers, in particular OFDM based transmissions utilizing DCM and preamble puncturing. More specifically, the illustrated concepts may enable efficient use of unlicensed spectrum by enabling the use of preamble puncturing for DCM. Further, since DCM duplicates the code bits, combining DCM with the channel code, e.g., an LDPC, the code rate is effectively halved. For example, the concatenation of existing channel codes, e.g., such as LDPC codes, and DCM may yield effective code rates as low as 1/4. Accordingly, the illustrated concepts may also be used to increase the robustness of a punctured transmission, without a need to design, evaluate and implement new, low-rate codes. Rather, the existing codes can be re-used. Further, the illustrated concepts can be implemented with low complexity. 
     It is to be understood that the examples and embodiments as explained above are merely illustrative and susceptible to various modifications. For example, the illustrated concepts may be applied in connection with various kinds of wireless technologies, without limitation to WLAN technologies. Further, it is noted that the concepts may be applied with respect to various configurations of separating the bandwidth of the wireless medium into RUs or bandwidth segments. Further, the concepts may be applied with respect to various types of APs and stations. Moreover, it is to be understood that the above concepts may be implemented by using correspondingly designed software to be executed by one or more processors of an existing device or apparatus, or by using dedicated device hardware. Further, it should be noted that the illustrated apparatuses or devices may each be implemented as a single device or as a system of multiple interacting devices or modules. 
     In view of the above, embodiments provided in the present disclosure include: 
     Embodiment 1 
     A method of controlling wireless transmissions in a wireless communication system, the method comprising:
     a wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) transmitting user data using Orthogonal Frequency Division Multiplexing, OFDM, modulation on a shared wireless medium having a bandwidth organized in multiple resource units;   based on a mapping of the user data to the resource units, the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) modulating a symbol of the user data onto a first set of subcarriers of a first resource unit of the resource units and redundantly modulating the symbol onto a second set of subcarriers of a second resource unit of the resource units,   wherein the mapping of the user data to the resource units is based on possible puncturing patterns applied to the resource units.   

     Embodiment 2 
     The method according to embodiment 1, 
     wherein the mapping of the user data to the resource units is configured to prevent that both the first resource unit and the second resource unit are subject to puncturing. 
     Embodiment 3 
     The method according to embodiment 1 or 2, 
     wherein the mapping of the user data to the resource units is based on information indicating allowed puncturing patterns. 
     Embodiment 4 
     The method according to embodiment 3, 
     wherein at least a part of the information indicating the allowed puncturing patterns is preconfigured in the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ). 
     Embodiment 5 
     The method according to any one of embodiments 1 to 4, 
     wherein the mapping of the user data to the resource units is based on information indicating forbidden puncturing patterns. 
     Embodiment 6 
     The method according to embodiment 5, 
     wherein at least a part of the information indicating the forbidden puncturing patterns is preconfigured in the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ). 
     Embodiment 7 
     The method according to any one of embodiments 1 to 6, 
     wherein the mapping of the user data to the resource units is based on interference levels on the resource units. 
     Embodiment 8 
     The method according to any one of embodiments 1 to 7, 
     wherein the said modulating of the symbol to the first set of subcarriers and redundantly modulating the symbol to the second set of subcarriers is based on Dual Carrier Modulation. 
     Embodiment 9 
     The method according to any one of embodiments 1 to 8, 
     wherein the multiple resource units are allocated to different users. 
     Embodiment 10 
     The method according to any one of embodiments 1 to 9, 
     wherein the wireless transmitter ( 10 ;  1100 ;  1400 ) is an access point of the wireless communication system. 
     Embodiment 11 
     The method according to any one of embodiments 1 to 9, 
     wherein the wireless transmitter ( 11 ;  1100 ;  1400 ) is a wireless device in communication with an access point of the wireless communication system. 
     Embodiment 12 
     The method according to any one of embodiments 1 to 11, 
     wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family. 
     Embodiment 13 
     A method of controlling wireless transmissions in a wireless communication system, the method comprising:
     a wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) receiving user data using Orthogonal Frequency Division Multiplexing, OFDM, modulation on a shared wireless medium having a bandwidth organized in multiple resource units;   based on a mapping of the user data to the resource units, the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) demodulating a symbol of the user data from a first set of subcarriers of a first resource unit of the resource units and redundantly demodulating the symbol from a second set of subcarriers of a second resource unit of the resource units,   wherein the mapping of the user data to the resource units is based on possible puncturing patterns applied to the resource units.   

     Embodiment 14 
     The method according to embodiment 13, 
     wherein the mapping of the user data to the resource units is configured to prevent that both the first resource unit and the second resource unit are subject to puncturing. 
     Embodiment 15 
     The method according to embodiment 13 or 14, 
     wherein the mapping of the user data to the resource units is based on information indicating allowed puncturing patterns. 
     Embodiment 16 
     The method according to embodiment 15, 
     wherein at least a part of the information indicating the allowed puncturing patterns is preconfigured in the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ). 
     Embodiment 17 
     The method according to any one of embodiments 13 to 16, 
     wherein the mapping of the user data to the resource units is based on information indicating forbidden puncturing patterns. 
     Embodiment 18 
     The method according to embodiment 17, 
     wherein at least a part of the information indicating the forbidden puncturing patterns is preconfigured in the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ). 
     Embodiment 19 
     The method according to any one of embodiments 13 to 18, 
     wherein the mapping of the user data to the resource units is based on interference levels on the resource units. 
     Embodiment 20 
     The method according to any one of embodiments 13 to 19, 
     wherein the said demodulating of the symbol from the first set of subcarriers and redundantly modulating the symbol from the second set of subcarriers is based on Dual Carrier Modulation. 
     Embodiment 21 
     The method according to any one of embodiments 13 to 20, 
     wherein the multiple resource units are allocated to different users. 
     Embodiment 22 
     The method according to any one of embodiments 13 to 21, 
     wherein the wireless receiver ( 10 ;  1300 ;  1500 ) is an access point of the wireless communication system. 
     Embodiment 23 
     The method according to any one of embodiments 13 to 21, 
     wherein the wireless receiver ( 11 ;  1300 ;  1500 ) is a wireless device in communication with an access point of the wireless communication system. 
     Embodiment 24 
     The method according to any one of embodiments 13 to 23, 
     wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family. 
     Embodiment 25 
     A wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) for a wireless communication system, the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) being configured to:
     transmit user data using Orthogonal Frequency Division Multiplexing, OFDM, modulation on a shared wireless medium having a bandwidth organized in multiple resource units;   based on a mapping of the user data to the resource units, modulate a symbol of the user data onto a first set of subcarriers of a first resource unit of the resource units and redundantly modulate the symbol onto a second set of subcarriers of a second resource unit of the resource units,   wherein the mapping of the user data to the resource units is based on possible puncturing patterns applied to the resource units.   

     Embodiment 26 
     The wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) according to embodiment 25, 
     wherein the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) is configured to perform a method according to any one of embodiments 2 to 12. 
     Embodiment 27 
     The wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) according to embodiment 25 or 26, comprising: at least one processor ( 1450 ), and 
     a memory ( 1460 ) containing program code executable by the at least one processor ( 1450 ), whereby execution of the program code by the at least one processor ( 1450 ) causes the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) to perform a method according to any one of embodiments 1 to 12. 
     Embodiment 28 
     A wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) for a wireless communication system, the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) being configured to:
     receive user data using Orthogonal Frequency Division Multiplexing, OFDM, modulation on a shared wireless medium having a bandwidth organized in multiple resource units;   based on a mapping of the user data to the resource units, demodulate a symbol of the user data from a first set of subcarriers of a first resource unit of the resource units and redundantly demodulate the symbol from a second set of subcarriers of a second resource unit of the resource units,   wherein the mapping of the user data to the resource units is based on possible puncturing patterns applied to the resource units.   

     Embodiment 29 
     The wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) according to embodiment 28, 
     wherein the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) is configured to perform a method according to any one of embodiments 14 to 24. 
     Embodiment 30 
     The wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) according to embodiment 24 or 25, comprising:
     at least one processor ( 1550 ), and   a memory ( 1560 ) containing program code executable by the at least one processor ( 1550 ), whereby execution of the program code by the at least one processor ( 1550 ) causes the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) to perform a method according to any one of embodiments 13 to 24.   

     Embodiment 31 
     A system, comprising:
     a wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) and a wireless receiver ( 10 ,  11 ;  1300 ;  1500 );   the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) being configured to:   transmit user data using Orthogonal Frequency Division Multiplexing, OFDM, modulation on a shared wireless medium having a bandwidth organized in multiple resource units, and   based on a mapping of the user data to the resource units, modulate a symbol of the user data onto a first set of subcarriers of a first resource unit of the resource units and redundantly modulate the symbol onto a second set of subcarriers of a second resource unit of the resource units,   wherein the mapping of the user data to the resource units is based on possible puncturing patterns applied to the resource units,   the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) being configured to:   based on the mapping of the user data to the resource units, demodulate the symbol of the user data from the first set of subcarriers and redundantly demodulate the symbol from the second set of subcarriers.   

     Embodiment 32 
     A computer program or computer program product comprising program code to be executed by at least one processor ( 1450 ) of a wireless transmitter ( 10 , 11 ;  1100 ;  1400 ), whereby execution of the program code causes the wireless transmitter ( 10 , 11 ;  1100 ;  1400 ) to perform a method according to any one of embodiments 1 to 12. 
     Embodiment 33 
     A computer program or computer program product comprising program code to be executed by at least one processor ( 1550 ) of a wireless receiver ( 10 ,  11 ;  1300 ;  1500 ), whereby execution of the program code causes the wireless receiver ( 10 ,  11 ;  1300 ;  1500 ) to perform a method according to any one of embodiments 13 to 24.