A method for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device, a related network node, a related first wireless device, and a related second wireless device

Abstract

A method is disclosed, performed by a network node, for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device, based on joint precoding of the first symbol and a second symbol of the second wireless device in at least one second resource element of a second transmission from the second wireless device; the method comprising transmitting, to a first wireless device, first control information defining how first side information, to be sent to the second wireless device over a direct link between the first wireless device and the second wireless device for transmission in the second transmission is to be obtained from the first symbol; transmitting, to a second wireless device, second control information defining how to process the first side information with the second symbol for provision of second data to be sent in the second transmission.

Description

A METHOD FOR ENABLING A SECOND WIRELESS DEVICE TO ASSIST A FIRST TRANSMISSION OF A FIRST SYMBOL FROM A FIRST WIRELESS DEVICE, A RELATED NETWORK NODE, A RELATED FIRST WIRELESS DEVICE, AND A RELATED SECOND WIRELESS DEVICEThe present disclosure pertains to the field of wireless communications. The present disclosure relates to a method for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device, a related network node, a related first wireless device, and a related second wireless device.BACKGROUNDTelecommunication systems have evolved over the years to accommodate the growing demand for high-speed and reliable connectivity. One of the challenges faced in modern telecommunication systems is the efficient utilization of network resources to meet increasing demands of data-heavy transmissions and services. Conventional approaches have shown limitations in achieving the required levels of performance, especially in scenarios with high user density or in environments with complex radio conditions.Collaboration and aggregation between wireless devices, such as user equipment, UE, have been proposed as a way to enhance system throughput. However, several challenges remain in achieving its implementation and optimal performance given practical constraints.SUMMARYOne of the practical constraints for collaboration and aggregation is that UEs have limited capacity between each other, such as a limited direct link between each other.Accordingly, there is a need for devices and methods for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device, which may mitigate, alleviate or address the shortcomings existing and may provide for implementation of collaboration and / or aggregation between wireless devices.It may be appreciated that in order to determine a best precoder between two wireless devices, at least one of the two wireless devices may need to possess full channel state information, CSI. This is, however, typically not available in frequency division duplexing, FDD bands.Furthermore, even in the face of time division duplexing, TDD, bands and full channel reciprocity it may be challenging since the number of network node (such as gNB) antennas may be large and there may be no feasible method for facilitating full CSI to the wireless device (such as UE). Thus, there are no existing 3GPP protocols for it, and introducing one solely for the purpose of wireless device collaboration / aggregation (UE-C / A) may appear excessive.Disclosed is a method, performed by a network node, for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device, based on joint precoding of the first symbol and a second symbol of the second wireless device in at least one second resource element of a second transmission from the second wireless device. The method comprises transmitting, to a first wireless device, first control information defining how first side information, to be sent to the second wireless device over a direct link between the first wireless device and the second wireless device for transmission in the second transmission is to be obtained from the first symbol. The method comprises transmitting, to a second wireless device, second control information defining how to process the first side information with the second symbol for provision of second data to be sent in the second transmission.Further, a network node comprising memory circuitry, processor circuitry, and a wireless interface is provided. The network node is configured to perform any of the methods performed in a network node as disclosed herein.It is an advantage of the present disclosure that the disclosed method and network node enables transmission assistance between wireless devices. The disclosed method and network node enables an improved implementation of collaboration and aggregation between wireless devices, e.g., by coordinating the collaboration and aggregation between wireless devices. For example, the present disclosure enables the system to exploit the collaboration and / or aggregation to its fullest extent. In other words, the present disclosure maximizes the benefit of collaboration and / or aggregation. For example, the disclosed method and network node enables joint precoding by wireless devices.The present disclosure enables enhanced throughput, such as transmission throughput, in wireless telecommunication systems. In other words, the present disclosure enables gains by enabling joint precoding.Disclosed is a method, performed by a second wireless device, for assisting a first transmission of a first symbol from a first wireless device, based on joint precoding of the first symbol and a second symbol of the second wireless device in at least one second resource element of a second transmission from the second wireless device. The method comprises receiving, from the first wireless device over a direct link between the first wireless device and the second wireless device, first side information. The method comprises receiving, from a network node, second control information defining how to process the first side information with the second symbol for provision of second data to be sent in the second transmission. The method comprises transmitting, in the second transmission to the network node, the second data.Further, a second wireless device comprising memory circuitry, processor circuitry, and a wireless interface is provided. The second wireless device is configured to perform any of the methods performed in a second wireless device as disclosed herein.It is an advantage of the present disclosure that the disclosed method and second wireless device enable transmission assistance of a first wireless device, such as assistance of the first wireless device in transmitting a first symbol. The disclosed method and second wireless device enable the implementation of collaboration and aggregation between the second wireless device and the first wireless device. For example, the disclosed method and second wireless device enables joint precoding by the second wireless device and the first wireless device.The present disclosure enables enhanced throughput, such as transmission throughput, in wireless telecommunication systems.Disclosed is a method, performed by a first wireless device, for assisting a first transmission of a first symbol from the first wireless device, based on joint precoding of the first symbol and a second symbol of the second wireless device in at least one second resource element of a second transmission from the second wireless device. The method comprises transmitting, to the second wireless device over a direct link between the first wireless device and the second wireless device, first side information.Further, a first wireless device comprising memory circuitry, processor circuitry, and a wireless interface is provided. The first wireless device is configured to perform any of the methods performed in a first wireless device as disclosed herein.It is an advantage of the present disclosure that the disclosed method and first wireless device enables the first wireless device to be assisted in a transmission, e.g., assisted in a transmission of a first symbol. The disclosed method and first wireless device enable the implementation of collaboration and aggregation between the second wireless device and the first wireless device. For example, the disclosed method and first wireless device enables joint precoding by the second wireless device and the first wireless device. The present disclosure enables enhanced throughput, such as transmission throughput, in wireless telecommunication systems.BRIEF DESCRIPTION OF THE DRAWINGSThe above and other features and advantages of the present disclosure will become readily apparent to those skilled in the art by the following detailed description of examples thereof with reference to the attached drawings, in which:Fig. 1 is a diagram illustrating an example wireless communication system comprising an example network node, an example first wireless device, and an example second wireless device according to this disclosure,Figs. 2A-2B is a flow-chart illustrating an example method, performed in a network node of a wireless communication system, for enabling a second wireless device to assist a first transmission of a first symbol from a first wireless device according to this disclosure,Figs. 3A-3B is a flow-chart illustrating an example method, performed in a second wireless device of a wireless communication system, for assisting a first transmission of a first symbol from a first wireless device according to this disclosure,Figs. 4A-4B is a flow-chart illustrating an example method, performed in a first wireless device of a wireless communication system, for assisting a first transmission of a first symbol from a first wireless device according to this disclosure,Fig. 5 is a block diagram illustrating an example network node according to this disclosure,Fig. 6 is a block diagram illustrating an example second wireless device according to this disclosure,Fig. 7 is a block diagram illustrating an example first wireless device according to this disclosure,Fig. 8 illustrates an example scenario where an example technique as disclosed herein is applied, andFig. 9A shows a signaling diagram where a technique as disclosed herein is applied. Fig. 9A shows an example scenario where one-sided assistance is performed; andFig. 9B shows a signaling diagram where a technique as disclosed herein is applied. Fig. 9B shows an example scenario where two-sided assistance is performed (such as mutual assistance).DETAILED DESCRIPTIONVarious examples and details are described hereinafter, with reference to the figures when relevant. It should be noted that the figures may or may not be drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the examples. They are not intended as an exhaustive description of the disclosure or as a limitation on the scope of the disclosure. In addition, an illustrated example needs not have all the aspects or advantages shown. An aspect or an advantage described in conjunction with a particular example is not necessarily limited to that example and can be practiced in any other examples even if not so illustrated, or if not so explicitly described.As discussed in detail herein, the present disclosure relates to a wireless communication system 1 comprising a cellular system, for example, a 3GPP wireless communication system.The wireless communication system 1 comprises a first wireless device 300, a second wireless device 300A, a network node 400, and / or a core network (CN) node 600.A network node disclosed herein refers to a radio access network node operating in the radio access network, such as a base station, an evolved Node B, eNBs, a global Node B, gNBs.The wireless communication system 1 described herein may comprise one or more wireless devices 300, 300A, and / or one or more network nodes 400, such as one or more of: a base station, an eNB, a global Node B and / or an access point.A wireless device may refer to a mobile device and / or a user equipment, UE.The wireless device 300, 300A may be configured to communication with the network node 400 via a wireless link (or radio access link) 10, 10A. The first wireless device 300 may be configured to communicate with the second wireless device 300A and vice-versa, via a direct link 10B, such as a wireless link (or radio access link).The figures are schematic and simplified for clarity, and they merely show details which aid understanding the disclosure, while other details have been left out. Throughout, the same reference numerals are used for identical or corresponding parts.Fig. 1 is a diagram illustrating an example wireless communication system 1 comprising an example network node 400, an example first wireless device 300, and an example second wireless device 300A according to this disclosure.As discussed in detail herein, the present disclosure relates to a wireless communication system 1 comprising a cellular system, for example, a 3GPP wireless communication system.The wireless communication system 1 comprises a first wireless device 300, a second wireless device 300A, and / or a network node 400.A network node disclosed herein refers to a radio access network node operating in the radio access network, such as a base station, an evolved Node B, eNB, gNB in NR. In one or more examples, the RAN node is a functional unit which may be distributed in several physical units.A core network, CN, node disclosed herein refers to a network node operating in the core network, such as in the Evolved Packet Core Network, EPC, and / or a 5G Core Network, 5GC.Examples of CN nodes in EPC include a Mobility Management Entity, MME.In one or more examples, RAN node is a functional unit which may be distributed in several physical units.The wireless communication system 1 described herein may comprise one or more wireless devices 300, 300A, and / or one or more network nodes 400, such as one or more of: a base station, an eNB, a gNB and / or an access point.A wireless device may refer to a mobile device and / or a user equipment, UE.The wireless devices 300, 300A may be configured to communicate with the network node 400 via a wireless link (or radio access link) 10, 10A.The first wireless device 300 may be configured to communicate with the second wireless device 300A and vice-versa, via a direct link 10B, such as a wireless link (or radio access link).The first wireless device 300 and the second wireless device 300A, such as the first UE and the second UE, transmit in the uplink, UL, to the network node 400, such as gNB 400. The network node 400 may have M antennas. The first wireless device 300 may have data symbol x₁, such as the first symbol x1 as disclosed herein, and the second wireless device 300A may have data symbol x2, such as the second symbol x2 as disclosed herein, to transmit. The first symbol x1 may be seen as a symbol to be transmitted by the first wireless device 300 to the NN 400. In other words, the first symbol x₁ may be seen as a symbol intended to be transmitted by the first wireless device 300 in the first transmission to the NN 400. The second symbol x2 may be seen as a symbol to be transmitted by the second wireless device 300A to the NN 400. The second symbol x2 may be seen as a symbol intended to be transmitted by the second wireless device 300A in the second transmission to the NN 400. The said two symbols may be drawn, e.g., from alphabets with cardinalities 2k1 and 2k2, respectively. It may be appreciated that other cardinalities that are not of the power of 2 are not precluded.It may be appreciated that the limitation (or assumption) to scalar data values may be for simplifying notation, and shall not be seen as limiting. The skilled person would understand how to extend the scalar data to vector-valued data instead. The fact that data symbol may be a scalar may be seen as the wireless devices (such as UEs) having single ports. Therefore, the examples presented herein where the data symbols are presented as scalar values may also be true for symbols being vectors. For example, K1 and K2 may be seen as total numbers of bits associated to said vectors.The first wireless device 300 and the second wireless device 300A may be capable of communicating side information via the direct link 10B, exchanging respectively side information via the signals 21 and 22 to each other. The first side information z₁ may be seen as side information to be transmitted by the first wireless device 300 to the second wireless device 300A. The second side information z2 may be seen as side information to be transmitted by the second wireless device 300A to the first wireless device 300. The exchanging between the wireless devices may be seen as error-and-delay-free side information through the signals Z1 and 22. However, this assumption of delay-free side information (such as side information transmitted via direct link between the WDs) may not be very restrictive. This is so since it may be assumed later that the side information may be generated from the intended transmit data Xk. As the intended transmit data xx may be known in advance, the first wireless device 300 can send its side information generated from future data symbols to the second wireless device, thereby rendering any delay on the direct link channels irrelevant. The signals 21 and 22 may be assumed to be rate-limited to R₁ and R2 bits / channel use, respectively. In other words, the direct link between the first wireless device and the second wireless device may be seen as rate-limited. In the present disclosure, the practical restriction that the direct link (such as backhaul between the UEs) is rate-limited to rates less than the intended rates of the UL itself may be considered. The transmitted signal sk from wireless device k may be determined by a function fk(,) with the intended data xx and the side information Z≠k as arguments, i.e., s₁ = f1(x1, Z2) and S2 = f2(x2, 21). Finally, the received signal at the network node readsy = H [1] + n,where it may be assumed that n is white complex Gaussian noise with sample variance No.H[h2] may be seen as a radio channel between the NN 400 and the wireless devices, where the length of the vectors h1 and h2 may be the number of the NN's receiving antennas.For example, the rates R₁ and R₂ may apply at a specific subcarrier used for the following example. It may be appreciated that at other subcarriers the rates could be zero. For example, if it is assumed that 1024 subcarriers are used and that K₁=K2=6 bits at all subcarriers. This implies that, save for the loss due to coding and overhead, that the sum-rate in the UL is ≈12000 bits / OFDM symbol interval. At 15 kHz subcarrier spacing, this gives a total rate of ≈180Mbit / s. The direct link 10B (such as backhaul) between the wireless devices, WDs, could be synthesized through a low-rate protocol, such as Bluetooth, and have rates that are orders of magnitude lower than the 180Mbit / s. For example, if it is assumed that the rates in the direct link 10B are limited to a mere 750 kbit / s per direction. It may be appreciated that per symbol interval, a rate of ≈750000 / 15000=50 bits may be obtained. These bits may now be spread across the 1024 subcarriers. Spreading them equally, would yield rates R₁=R2=50 / 1024=0.05 bits / channel use. This may, however, be too little to have any noticeable impact, wherefore it may be more suitable to concentrate the 50 bits of side-information to a set of particularly weak subcarriers. For example, the 25 weakest subcarriers with a uniform allocation. At those 25 subcarriers, rates of R₁=R2=50 / 25=2 bits / channel use may be obtained. In one or more examples or embodiments, the technique disclosed herein may be applied to a selected set of subcarriers, such as a set of weakest subcarriers.In one or more examples or embodiments, the first wireless device and the second wireless device (such as UEs) may exchange side-information, form their transmitted signals, and transmit the combination of signals according to what the network scheduled, thereby enabling the reception point to recreate the combined original message.Figs. 2A-2B show a flow diagram of an example method 100, performed by a network node according to the disclosure, for enabling a second wireless device (UE2, WD2) to assist a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1, WD1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device. The network node is the network node disclosed herein, such as network node 400 of Fig. 1, Fig. 5. And Fig. 9. The first wireless device is the first wireless device as disclosed herein, such as first wireless device 300 of Fig. 1, Fig. 7, and Fig. 9. The second wireless device is the second wireless device as disclosed herein, such as second wireless device 300A of Fig. 1, Fig. 6, and Fig. 9.The first transmission may be seen as a transmission from the first wireless device to the network node, NN, such as an uplink transmission from the first wireless device to the NN. The first symbol may be seen as a symbol to be transmitted by the first wireless device to the NN. In other words, the first symbol may be seen as a symbol intended to be transmitted by the first wireless device in the first transmission to the NN. The second symbol may be seen as a symbol intended to be transmitted by the second wireless device in the second transmission to the NN. The first symbol may be seen as a first data symbol and / or the second symbol may be seen as a second data symbol. In one or more examples or embodiments, it may only be the second wireless device assisting the first wireless device and not mutual assistance. In other words, the assistance may be one-sided assistance. In one or more examples or embodiments, the second wireless device may assist the first wireless device and vice-versa. The wireless devices may therefore provide mutual assistance to each other. In other words, the assistance may be two-sided assistance.Joint precoding of the first symbol and the second symbol may be seen as the first wireless device and the second wireless device collaborating in the precoding of respective data symbols intended to be sent from the first wireless device and the second wireless device respectively. Joint precoding may comprise jointly precoding the first symbol (such as a portion of the first symbol, e.g., the first side information) and the second symbol in the at least one second resource element of the second transmission. For example, joint precoding of the first symbol and the second symbol may comprise mapping the first symbol (such as a portion of the first symbol, e.g., the first side information) and the second symbol to the at least second resource element. The second wireless device and / or the first wireless device may for example be preconfigured to perform the mapping. The at least one second resource element may be seen as a resource of the second wireless device (such as allocated resource), for performing the second transmission.The second transmission may be seen as a second, assisting transmission, e.g., for assisting the first wireless device, such as for assisting the first wireless device in the transmission of the first symbol. In one or more example network nodes, the at least first resource element and the at least second resource element are the same resource. In other words, the first transmission and the second transmission may be seen as taking place in the same time-frequency resource.The method 100 comprises transmitting S102, to the first wireless device, first control information defining how first side information (z1), to be sent to the second wireless device over a direct link between the first wireless device and the second wireless device for transmission in the second transmission, is to be obtained from the first symbol. In other words, the first control information is defining how the first wireless device shall obtain the first side information from the first symbol, e.g., how to generate and / or derive the first side information from the first symbol. In one or more examples or embodiments, the first control information is defining how to send the first side information to second wireless device over the direct link. In one or more examples or embodiments, the direct link may be seen as or comprise one or more of: a PC5 interface and / or a non-3GPP link, such as provided by WLAN, Bluetooth, UWB, and / or other sidelinks between the first wireless device and the second wireless device.In other words, the network node may indicate to the first wireless device, such as the first UE (UE1), how the first side-information z₁ should be determined from the first data symbol x₁. For example, the network node may indicate how z₁, which should be used in function fix(,) at a given time-frequency resource (such as the at least one second resource element), should be derived from the first data symbol to be sent at that resource. It may be appreciated that the first wireless device and the second wireless device may operate their direct link to perform this.The method 100 comprises transmitting S110, to the second wireless device, second control information defining how to process the first side information with the second symbol for provision of second data to be sent in the second transmission. The second wireless device may be configured to process the first side information with the second symbol for provision of second data to be sent in the second transmission.In other words, the second control information may define how to map the first symbol (such as a portion of the first symbol, e.g., the first side information) and the second symbol to the at least second resource element.For example, the second control information may define how to combine the first side information with the second symbol in the second resource element for transmission in the second transmission. In one or more examples or embodiments, the second control information may be transmitted to the second wireless device via the first wireless device, e.g., relayed by the first wireless device to the second wireless device via the direct link.The second data may be seen as a processed version of the first side information and the second symbol, such as result of the processing of the first side information and the second symbol.In one or more examples or embodiments, the method for enabling a second wireless device (UE2) to assist a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device may be implemented in various ways but may affect several parts of the 3GPP layers. For example, the present method may affect the MAC layer for creating PDUs for multiple links (e.g., when the direct link is based on sidelink 3GPP backhaul). Further, the present method may affect the RRC level for the connection establishment and configurations of settings for both links when the direct link is based on sidelink 3GPP backhaul.It may be appreciated that the collaboration may take place as a 3GPP-sidelink and / or could be a non-3GPP collaboration.In one or more example methods, the first control information indicates how to extract (such as generate) bits from the first symbol to be transmitted to the second wireless device, for provision of the first side information over the direct link between the first wireless device and the second wireless device, such as over sidelink. It may be appreciated that to generate bits from the first symbol may comprise to extract the weakest bits from the first symbol. In other words, the first control information may indicate to extract the weakest bits from the first symbol. The first control information may indicate which bits to extract from the first symbol and / or criteria or conditions to be satisfied by the bits for being extracted. An example of a linear extraction of bits may be as follows:the first symbol x1 may consist of the 4 bits x1[0], x1[1], x1[2], x1[3], and the first side information z1 may consist of the 2 bits z1[0] and z1[1]. Then, z1[0] may be formed from {x1[0], x1[1], x1[2], x1[3]} by the mapping z1[0] = a0_0*x1[0] + a0_1*x1[1] + a0_2*x1[2]+ a0_3*x1[3].Similarly, it may obtained that z1[1] = a1_0*x1[0] + a1_1*x1[1] + a1_2*x1[2]+ a1_3*x1[3]. The above may be seen as a linear mapping from the first symbol x1 to the first side information z1.However, non-linear mapping may also be possible.It may be appreciated that the extraction of bits (or generation of bits) from the first symbol may not be linear. For example, the generation of the first side information z1 from the first symbol x1 may not be linear. The extraction of bits or generation of bits may be seen as forming new bits based on the first symbol x1. It may be appreciated that bits may be generated and not extracted when the process is non-linear. For example, the extracted first side information z1 may be specified or described with fewer bits than the number of necessary bits to specify or describe the first symbol x1. For example, if the first symbol is specified by 4 bits, but only 2 bits can be sent in the first side information. These 2 bits may be generated based on the first symbol's 4 bits, such as based on a set of linear combinations of the 4 bits. Formulated differently, the extraction or determination of side information may be generated or based on only a part of the first symbol.It may be appreciated that the description relating to the second control information may also apply to the description of the first control information.In one or more example methods, wherein the second control information comprises one or more of: a constellation mapping, a phase shift, and a power level to apply to the first side information when performing the second transmission.A constellation mapping may be seen as a technique used to represent complex signals in a simplified, e.g., two-dimensional way. The second control information may comprise information indicative of a set of parameters for using constellation mapping at the second wireless device, e.g., to pre-code the first side information and the second symbol using constellation mapping.The second control information comprising a phase shift may be seen as the second control information comprising a phase shift value to be applied by a wireless device, e.g., to create a positive interference between the first wireless device and the second wireless device. In other words, the network node may be configured to control a phase of the signals from the first wireless device and the second wireless device.The second control information comprising a power level may be seen as the second control information comprising power level information and / or settings to be applied by the wireless device. For example, the network node may be configured to control a transmission power of the first wireless device and / or the second wireless device, e.g., to align the transmission power of the wireless devices. The relative amplitudes between the first signals sent from the first wireless device and the second signals sent from the second wireless device may have to be kept intact.In one or more example methods, the second control information comprises information defining how to combine the first side information with the second symbol, to be transmitted by the second wireless device, in the second transmission. In other words, the second control information may define how to combine the first side information with the second symbol in the at least one second resource element for transmission in the second transmission.In one or more examples or embodiments, the second control information comprises information indicative of a frequency resource and / or time resource of the at least one second resource element.In one or more examples or embodiments, the first control information comprises information indicative of a frequency resource and / or time resource of the at least one first resource element as disclosed herein.In one or more example methods, the first control information comprises a first precoding function and / or a first precoding function form to apply when performing the first transmission and / or the second control information comprises a second precoding function and / or a second precoding function form to apply when performing the second transmission.For example, the network node may indicate how the first symbol and the second symbol, such as the first side information z₁ and / or the second side information 22, are pre-coded using the first precoding function and / or the second precoding function at a given time-frequency resource (such as the at least one first resource element and / or the at least one second resource element). A precoding function form, such as the first precoding function form and / or the second precoding function form, may be seen as functional forms of the precoding functions. A precoding function form may for example be a linear combination form.In one or more example methods, the method 100 comprises receiving S116, from the second wireless device, the second data transmitted in the second transmission. The second data may comprise or be indicative of the first side information (such as a part of the first side information) and the second symbol (such as part of the second symbol or the entire second symbol). It may be appreciated that when the first wireless device assists the second transmission of the second symbol, the second data may comprise or be indicative of the second symbol (x2) minus the second side information (z2). For example, when the second wireless device is assisted by the first wireless device, the second wireless device may not need to transmit the full second symbol x2. In other words, when the second wireless device is assisted by the first wireless device, the second wireless device may not need to transmit the part of the second symbol x2 that the first wireless device assists with (e.g., the second side information z2). In one or more examples or embodiments, the second wireless device may still transmit the full second symbol x2 even when being assisted by the first wireless device.In one or more example methods, the method 100 comprises receiving S104, from the first wireless device and / or the second wireless device, information indicative of a collaboration capability of the first wireless device and / or the second wireless device. Receiving S104 information may comprise receiving a first primary message indicative of a collaboration capability of the first wireless device from the first wireless device and / or receiving a second primary message indicative of a collaboration capability of the second wireless device from the second wireless device. In other words, the information may indicate whether the first wireless device and / or the second wireless device are capable of assisting a transmission of another wireless device, e.g., using joint precoding.In one or more example methods, the method 100 comprises receiving S106, from the first wireless device and / or the second wireless device, information indicative of a first data rate of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more examples or embodiments, the method 100 comprises receiving S106, from the first wireless device and / or the second wireless device, information indicative of a second data rate of transmission from the second wireless device to the first wireless device via the communication link between the first wireless device and the second wireless device.In other words, the information may indicate a data-rate of the direct link between the WDs (such as backhaul links). It may be appreciated that the data rate(s) may be different from the values Rk as disclosed in here, as those are specific for given subcarrier spacing. For example, the data-rate could be persistently configured or adapted with the link capacity. In the latter case, signaling by capability may not possible and instead RRC level and / or control channels level signaling may be used, such as RRC / MAC physical layer signaling.In one or more example methods, the method 100 comprises indicating S112, based on the first data rate to the first wireless device and / or the second wireless device, which set of subcarriers to be used in the first transmission and / or the second transmission. In other words, indicating S112 which set of subcarriers to be used in the second transmission may comprise determining the number of subcarriers to be used in the second transmission based on the first data rate and indicating the number of subcarriers to the second wireless device. In one or more examples or embodiments, indicating S112 which set of subcarriers to be used in the second transmission may comprise identifying the weakest subcarriers and indicating to the second wireless device which set of subcarriers to be used in the second transmission based on the weakest subcarriers.In one or more example methods, the method 100 comprises receiving S108, from the first wireless device and / or the second wireless device, a first reference signal and / or a second reference signal respectively. A reference signal, RS, such as the first reference signal and the second reference signal, may be seen as a sounding reference signal, SRS. The SRS is a RS that can be used by the network node to estimate a timing advance in relation to a WD. By receiving reference signals from the first wireless device and / or the second wireless device the channel state information, CSI, may be facilitated at the network node.In one or more example methods, the method 100 comprises indicating S114, to the first wireless device, a first modulation scheme and / or a first coding scheme to be used in the first transmission and / or indicating, to the second wireless device, a second modulation scheme and / or a second coding scheme to be used in the second transmission. A first example for the second transmission may be as follows: the NN (such as gNB) may indicate an MCS for the second symbol x2 and another MCS for the first symbol x1, for example when the first side information z1 consists of unmodulated bits. A second example for the second transmission may be as follows: the NN may indicate an MCS for the second symbol x2 and let the first side information z1 consist of modulated symbols (such as the second MCS for the first side information z1 being implicit in the first control information). A third example for the second transmission may be as follow: the second symbol x2 and the first side information z1 bits could be jointly modulated according to a single MCS indicated by the NN.In one or more examples or embodiments, the method 100 comprises determining, based on the first reference signal, a first modulation scheme and / or a first coding scheme to be used in the first transmission. In one or more examples or embodiments, the method 100 comprises determining, based on the second reference signal, a second modulation scheme and / or a second coding scheme to be used in the second transmission. In other words, the network node may indicate, based on the CSI and to the first wireless device and / or the second wireless device, which modulation and / or coding scheme, MCS, to use. Since the first symbol x1 and the second symbol x2 may be coded separately, the first side information z1 may only need a modulation scheme. It may be appreciated that a modulation scheme and / or coding scheme may indicate the format of a symbol of a wireless device, e.g., whether the format of a symbol should be 64QAM or 16QAM.In one or more example methods, the method is for enabling the first wireless device to assist the second transmission of the second symbol, based on joint precoding of the first symbol and the second symbol in at least one first resource element of the first transmission. The wireless devices may therefore provide mutual assistance to each other. In other words, the assistance may be two-sided assistance.The second transmission may be seen as a transmission from the second wireless device to the network node, NN, such as an uplink transmission from the second wireless device to the NN.The second symbol may be seen as a symbol to be transmitted by the second wireless device to the NN. The second symbol may be seen as a symbol intended to be transmitted by the second wireless device in the second transmission to the NN.In one or more example methods, the second control information defines how second side information (z2), to be sent to the first wireless device over the direct link for transmission in the first transmission, is to be obtained from the second symbol. In other words, the second control information is defining how the second wireless device shall obtain the second side information from the second symbol, e.g., how to generate and / or derive the second side information from the second symbol. In one or more examples or embodiments, the second control information is defining how to send the second side information to first wireless device over the direct link.In one or more example methods, the first control information defines how to process the second side information with the first symbol for provision of first data to be sent in the first transmission. In other words, the first control information may define how to map the second symbol (such as a portion of the second symbol, e.g., the second side information) and the first symbol to the at least first resource element. The first wireless device may be configured to process the second side information with the first symbol for provision of first data to be sent in the first transmission.For example, the first control information may define how to combine the second side information with the first symbol in the first resource element for transmission in the first transmission. In one or more examples or embodiments, the first control information may be transmitted to the first wireless device via the second wireless device, e.g., relayed by the second wireless device to the first wireless device via the direct link.The first data may be seen as a processed version of the second side information and the first symbol, such as result of the processing of the second side information and the first symbol.In one or more example methods, the first control information comprises information indicative of the at least one first resource element and / or the second control information comprises information indicative of the at least one second resource element. For example, the first control information comprises information indicative of a first frequency resource and / or a first time resource of the at least one first resource element. For example, the second control information comprises information indicative of a second frequency resource and / or a second time resource of the at least one second resource element.In one or more example methods, the second control information indicates how to extract (such as generate) bits from the second symbol to be transmitted to the first wireless device, for provision of the second side information over the direct link between the first wireless device and the second wireless device, such as over sidelink. The description relating to the second control information may also apply to the description of the first control information.In one or more example methods, the at least first resource element and the at least second resource element are the same resource. In other words, the first wireless device and the second wireless device are configured to transmit / send in the same resource element.In one or more example methods, the method 100 comprises receiving S118, from the first wireless device, the first data transmitted in the first transmission.The first data may comprise or be indicative of the second side information (such as a part of the second side information) and the first symbol (such as part of the first symbol or the entire first symbol). It may be appreciated that when the second wireless device assists the first transmission of the first symbol, the first data may comprise or be indicative of the first symbol (x1) minus the first side information (z1). For example, when the first wireless device is assisted by the second wireless device, the first wireless device may not need to transmit the full first symbol x1. In other words, when the first wireless device is assisted by the second wireless device, the first wireless device may not need to transmit the part of the first symbol x1 that the second wireless device assists with (e.g., the first side information z1). In one or more examples or embodiments, the first wireless device may still transmit the full first symbol x1 even when being assisted by the second wireless device.Fig. 3A-3B shows a flow diagram of an example method 200, performed by a second wireless device according to the disclosure, for assisting a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1, WD1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device (UE2, WD2) in at least one second resource element of a second transmission (S2) from the second wireless device (UE2). The device is the second wireless device disclosed herein, such as second wireless device 300A of Fig. 1, Fig. 6, and Fig. 9. The method 200 comprises receiving S202, from the first wireless device over a direct link between the first wireless device and the second wireless device, first side information.The method 200 comprises receiving S204, from a network node, second control information defining how to process the first side information with the second symbol for provision of second data to be sent in the second transmission. The method 200 may comprise processing S204A the first side information with the second symbol for provision of second data to be sent in the second transmission.The method 200 comprises transmitting S224, in the second transmission to the network node, the second data. In one or more examples or embodiments, the method 200 comprises transmitting S224, according to or based on the second control information and in the second transmission to the network node, the second data.In one or more example methods, the method 200 comprises combining S206, based on the second control information, the first side information with the second symbol for provision of the second data.In one or more example methods, the method 200 comprises applying S208 a second precoding function and / or a second precoding function form when performing the second transmission, e.g., based on the second control information comprising the second precoding function and / or the second precoding function form.In one or more example methods, the method 200 comprises transmitting S210, to the network node, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.In one or more example methods, the method 200 comprises transmitting S212, to the network node, information indicative of a first data rate of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more example methods, the method 200 comprises receiving S214, from the network node, information indicating which set of subcarriers to be used in the second transmission.In one or more example methods, the method 200 comprises transmitting S216, to the network node, a second reference signal.In one or more example methods, the method 200 comprises receiving S218, from the network node, information indicating a second modulation scheme and / or a second coding scheme to be used in the second transmission.In one or more example methods, the method is for assisting a second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and a second symbol (x2) in at least one second resource element of a first transmission (S1) from the first wireless device (UE1). The method comprises obtaining S220, based on the second control information, second side information (z2) from the second symbolIn one or more example methods, the method 200 comprises transmitting S222, to the first wireless device over the direct link, the second side information.In one or more example methods, obtaining S220 second side information comprises generating S220A bits from the second symbol to be transmitted to the first wireless device.In one or more example methods, transmitting S222 the second side information comprises providing S222A the second side information based on the generated bits from the second symbol.It may be appreciated that any of the definitions and terms used in the description of Figs. 2A-2B may also apply to the description of Figs. 3A-3B, Figs. 4A-4B, Fig. 5, Fig. 6, Fig. 7, Fig. 8, and Fig. 9 and vice versa. For example, any definitions and terms associated with the method performed by the network node disclosed herein may also apply and / or be used to the definitions and terms relating to the method performed by the first wireless device and the second wireless device and to the first wireless device and the second wireless device themselves as disclosed herein and vice versa.Fig. 4A-4B shows a flow diagram of an example method 500, performed by a first wireless device according to the disclosure, for assisting a first transmission (S1) of a first symbol (x1) from the first wireless device (UE1, WD1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device (UE2, WD2) in at least one second resource element of a second transmission (S2) from the second wireless device (UE2). The first wireless device is the first wireless device disclosed herein, such as wireless device 300 of Fig. 1, Fig. 7, and Fig. 9. The method 500 comprises transmitting S502, to the second wireless device over a direct link between the first wireless device and the second wireless device, first side information.In one or more example methods, the method 500 comprises generating S504 bits from the first symbol to be transmitted to the second wireless device.In one or more example methods, transmitting S502 the first side information comprises providing S502A the first side information based on the generated bits from the first symbol.In one or more example methods, the method 500 comprises applying S506 a first precoding function and / or a first precoding function form when performing the first transmission.In one or more example methods, the method 500 comprises transmitting S508 information indicative of a collaboration capability of the first wireless device and / or the second wireless device.In one or more example methods, the method 500 comprises transmitting S510, to the network node, information indicative of a first data rate of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more example methods, the method 500 comprises receiving S512, from the network node, information indicating which set of subcarriers to be used in the first transmission.In one or more example methods, the method 500 comprises transmitting S514, to the network node, a first reference signal.In one or more example methods, the method 500 comprises receiving S516, from the network node, information indicating a first modulation scheme and / or a first coding scheme to be used in the first transmission.In one or more example methods, the method is for assisting the second transmission of the second symbol from the second wireless device, based on joint precoding of the first symbol and the second symbol in at least one first resource element of the first transmission from the first wireless device. The method comprises receiving S518, from the second wireless device over the direct link, second side information.In one or more example methods, the method 500 comprises receiving S520, from the network node, first control information defining how to process the second side information with the first symbol for provision of first data to be sent in the first transmission.In one or more example methods, the method 500 comprises transmitting S522, in the first transmission to the network node, the first data. In one or more examples or embodiments, the method 500 comprises transmitting S224, according to or based on the first control information and in the first transmission to the network node, the second data.Fig. 5 shows a block diagram of an example network node 400 according to the disclosure. The network node 400 comprises memory circuitry 401, processor circuitry 402, and a wireless interface 403. The network node 400 may be configured to perform any of the methods disclosed in Figs. 2A-2B. In other words, the network node 400 may be configured for enabling a second wireless device (UE2) to assist a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2).The network node 400 may be configured to communicate with a user equipment, such as the user equipment node disclosed herein, using a wireless communication system.The wireless interface 403 is configured for wireless communications via a wireless communication system, such as a 3GPP system, such as a 3GPP system supporting one or more of: New Radio, NR, Long Term Evolution, LTE, Narrow-band IoT, NB-IoT, and Long Term Evolution - enhanced Machine Type Communication, LTE-M, and 3GPP system operated in licensed bands or unlicensed bands.The network node 400 is configured to transmit (such as via the wireless interface 403), to a first wireless device (UE1), first control information defining how first side information (z1), to be sent to the second wireless device (UE2) over a direct link between the first wireless device and the second wireless device for transmission in the second transmission (S2), is to be obtained from the first symbol (x1).The network node 400 is configured to transmit (such as via the wireless interface 403), to a second wireless device (UE2), second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (S2).In one or more example network nodes, the first control information indicates how to generate bits from the first symbol (x1) to be transmitted to the second wireless device, for provision of the first side information (z1) over the direct link between the first wireless device and the second wireless device.In one or more example network nodes, the second control information comprises one or more of: a constellation mapping, a phase shift, and a power level to apply to the first side information (z1) when performing the second transmission (S2).In one or more example network nodes, the second control information comprises information defining how to combine the first side information (z1) with the second symbol (x2), to be transmitted by the second wireless device, in the second transmission (S2).In one or more example network nodes, the first control information comprises a first precoding function and / or a first precoding function form to apply when performing the first transmission (s1) and / or the second control information comprises a second precoding function and / or a second precoding function form to apply when performing the second transmission (s2).In one or more example network nodes, the network node 500 is configured to receive (such as via the wireless interface 403), from the second wireless device, the second data transmitted in the second transmission.In one or more example network nodes, the network node 500 is configured to receive (such as via the wireless interface 403), from the first wireless device and / or the second wireless device, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.In one or more example network nodes, the network node 500 is configured to receive (such as via the wireless interface 403), from the first wireless device and / or the second wireless device, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more example network nodes, the network node 500 is configured to indicate (such as using the processor circuitry 402), based on the first data rate (R1) to the second wireless device, which set of subcarriers to be used in the second transmission (s2).In one or more example network nodes, the network node 500 is configured to receive (such as via the wireless interface 403), from the first wireless device and / or the second wireless device, a first reference signal and / or a second reference signal respectively.In one or more example network nodes, the network node 500 is configured to indicate (such as using the processor circuitry 402), to the first wireless device, a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1) and / or indicating, to the second wireless device, a second modulation scheme and / or a second coding scheme to be used in the second transmission (s2).In one or more example network nodes, the network node is configured to enable the first wireless device (UE1) to assist the second transmission (S2) of the second symbol (x2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1).In one or more example network nodes, the second control information defines how second side information (z2), to be sent to the first wireless device (UE1) over the direct link for transmission in the first transmission (S1), is to be obtained from the second symbol (x2).In one or more example network nodes, the first control information defines how to process the second side information with the first symbol (x1) for provision of first data to be sent in the first transmission (s1).In one or more example network nodes, the first control information comprises information indicative of the at least one first resource element and / or the second control information comprises information indicative of the at least one second resource element.In one or more example network nodes, the at least first resource element and the at least second resource element are the same resource. In other words, the first transmission and the second transmission may be seen as taking place in the same time-frequency resource.In one or more example network nodes, the network node 500 is configured to receive (such as via the wireless interface 403), from the first wireless device, the first data transmitted in the first transmission.Furthermore, the operations of the network node 400 may be considered a method that the network node 400 is configured to carry out. Also, while the described functions and operations may be implemented in software, such functionality may also be carried out via dedicated hardware or firmware, or some combination of hardware, firmware and / or software.Memory circuitry 401 may be one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, memory circuitry 401 may include a non-volatile memory for long term data storage and a volatile memory that functions as system memory for processor circuitry 402. Memory circuitry 401 may exchange data with processor circuitry 402 over a data bus. Control lines and an address bus between memory circuitry 401 and processor circuitry 402 also may be present (not shown in Fig. 5). Memory circuitry 401 is considered a non-transitory computer readable medium.Memory circuitry 401 may be configured to store information, such as control information, e.g., first control information and second control information, collaboration capability information, data rate information, reference signals, modulation schemes, coding schemes, first data, and / or second data, in a part of the memory.Fig. 6 shows a block diagram of an example second wireless device 300A according to the present disclosure. The second wireless device 300A comprises memory circuitry 301A, processor circuitry 302A, and a wireless interface 303A. The second wireless device 300A may be configured to perform any of the methods disclosed in Figs. 3A-3B. In other words, the second wireless device 300A may be configured for assisting a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2).The second wireless device 300A is configured to communicate with a network node, such as the network node 400 disclosed herein, using a wireless communication system.The second wireless device 300A is configured to receive (such as via the wireless interface 303A), from the first wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1).The second wireless device 300A is configured to receive (such as via the wireless interface 303A), from a network node, second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (s2).The second wireless device 300A is configured to transmit (such as via the wireless interface 303A), in the second transmission to the network node, the second data.In one or more example wireless devices, the second wireless device 300A is configured to combine (such as using the processor circuitry 302A), based on the second control information, the first side information (z1) with the second symbol (x2) for provision of the second data.In one or more example wireless devices, the second wireless device 300A is configured to apply (such as using the processor circuitry 302A) a second precoding function and / or a second precoding function form when performing the second transmission (S2).In one or more example wireless devices, the second wireless device 300A is configured to transmit (such as via the wireless interface 303A), to the network node, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.In one or more example wireless devices, the second wireless device 300A is configured to transmit (such as via the wireless interface 303A), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more example wireless devices, the second wireless device 300A is configured to receive (such as via the wireless interface 303A), from the network node, information indicating which set of subcarriers to be used in the second transmission (S2).In one or more example wireless devices, the second wireless device 300A is configured to transmit (such as via the wireless interface 303A), to the network node, a second reference signal.In one or more example wireless devices, the second wireless device 300A is configured to receive (such as via the wireless interface 303A), from the network node, information indicating a second modulation scheme and / or a second coding scheme to be used in the second transmission (S2).In one or more example wireless devices, the second wireless device is configured to assist a second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and a second symbol (x2) in at least one second resource element of a first transmission (S1) from the first wireless device (UE1). In one or more examples or embodiments, the second wireless device 300A is configured to obtain (such as using the processor circuitry 302A), based on the second control information, second side information (z2) from the second symbol (x2).In one or more example wireless devices, the second wireless device 300A is configured to obtain (such as using the processor circuitry 302A), based on the second control information, second side information (z2) from the second symbol (x2).In one or more example wireless devices, the second wireless device 300A is configured to transmit (such as via the wireless interface 303A), to the first wireless device over the direct link, the second side information (z2).In one or more example wireless devices, to obtain second side information (z2) comprises to generate (such as using the processor circuitry 302A) bits from the second symbol (x2) to be transmitted to the first wireless device.In one or more example wireless devices, to transmit the second side information (z2) comprises to provide (such as using the processor circuitry 302A) the second side information based on the generated bits from the second symbol (x2).The wireless interface 303A is configured for wireless communications via a wireless communication system, such as a 3GPP system, such as a 3GPP system supporting one or more of: New Radio, NR, Long Term Evolution, LTE, Narrow-band IoT, NB-IoT, and Long Term Evolution - enhanced Machine Type Communication, LTE-M, and 3GPP system operated in licensed bands or unlicensed bands.The operations of the second wireless device 300A may be embodied in the form of executable logic routines (for example, lines of code, software programs, etc.) that are stored on a non-transitory computer readable medium (for example, memory circuitry 301A) and are executed by processor circuitry 302A).Furthermore, the operations of the second wireless device 300A may be considered a method that the second wireless device 300A is configured to carry out. Also, while the described functions and operations may be implemented in software, such functionality may also be carried out via dedicated hardware or firmware, or some combination of hardware, firmware and / or software.Memory circuitry 301A may be one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, memory circuitry 301A may include a non-volatile memory for long term data storage and a volatile memory that functions as system memory for processor circuitry 302A. Memory circuitry 301A may exchange data with processor circuitry 302A over a data bus. Control lines and an address bus between memory circuitry 301A and processor circuitry 302A also may be present (not shown in Fig. 6). Memory circuitry 301A is considered a non-transitory computer readable medium.Memory circuitry 301A may be configured to store information, e.g., control information, such as first control information and second control information, collaboration capability information, data rate information, reference signals, modulation schemes, coding schemes, first data, and / or second data in a part of the memory.Fig. 7 shows a block diagram of an example first wireless device 300 according to the present disclosure. The first wireless device 300 comprises memory circuitry 301, processor circuitry 302, and a wireless interface 303. The first wireless device 300 may be configured to perform any of the methods disclosed in Figs. 4A-4B. In other words, the first wireless device 300 may be configured for assisting a first transmission (S1) of a first symbol (x1) from the first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2).The first wireless device 300 is configured to communicate with a network node, such as the network node 400 disclosed herein, using a wireless communication system.The first wireless device 300 is configured to transmit (such as via the wireless interface 303), to the second wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1).In one or more example wireless devices, the first wireless devices 300 is configured to generate (such as using the processor circuitry 302) bits from the first symbol (x1) to be transmitted to the second wireless device.In one or more example wireless devices, to transmit the first side information comprises to provide (such as using the processor circuitry 302) the first side information based on the generated bits from the first symbol.In one or more example wireless devices, the first wireless devices 300 is configured to apply (such as using the processor circuitry 302) a first precoding function and / or a first precoding function form when performing the first transmission (s1).In one or more example wireless devices, the first wireless devices 300 is configured to transmit (such as via the wireless interface 303) information indicative of a collaboration capability of the first wireless device and / or the second wireless device.In one or more example wireless devices, the first wireless devices 300 is configured to transmit (such as via the wireless interface 303), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device.In one or more example wireless devices, the first wireless devices 300 is configured to receive (such as via the wireless interface 303), from the network node, information indicating which set of subcarriers to be used in the first transmission (s1).In one or more example wireless devices, the first wireless devices 300 is configured to transmit (such as via the wireless interface 303), to the network node, a first reference signal.In one or more example wireless devices, the first wireless devices 300 is configured to receive (such as via the wireless interface 303), from the network node, information indicating a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1).In one or more example wireless devices, the first wireless device is configured to assist the second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1) from the first wireless device (UE1), the first wireless devices 300 is configured to receive (such as via the wireraless interface 303), from the second wireless device over the direct link, second side information (z2).In one or more example wireless devices, the first wireless devices 300 is configured to receive (such as via the wireless interface 303), from the network node, first control information defining how to process the second side information (z2) with the first symbol (x1) for provision of first data to be sent in the first transmission (s1).In one or more example wireless devices, the first wireless devices 300 is configured to transmit (such as via the wireless interface 303), in the first transmission to the network node, the first data.The wireless interface 303 is configured for wireless communications via a wireless communication system, such as a 3GPP system, such as a 3GPP system supporting one or more of: New Radio, NR, Long Term Evolution, LTE, Narrow-band IoT, NB-IoT, and Long Term Evolution - enhanced Machine Type Communication, LTE-M, and 3GPP system operated in licensed bands or unlicensed bands.The operations of the first wireless device 300 may be embodied in the form of executable logic routines (for example, lines of code, software programs, etc.) that are stored on a non-transitory computer readable medium (for example, memory circuitry 301) and are executed by processor circuitry 302).Furthermore, the operations of the first wireless device 300 may be considered a method that the first wireless device 300 is configured to carry out. Also, while the described functions and operations may be implemented in software, such functionality may also be carried out via dedicated hardware or firmware, or some combination of hardware, firmware and / or software.Memory circuitry 301 may be one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or other suitable device. In a typical arrangement, memory circuitry 301 may include a non-volatile memory for long term data storage and a volatile memory that functions as system memory for processor circuitry 302. Memory circuitry 301 may exchange data with processor circuitry 302 over a data bus. Control lines and an address bus between memory circuitry 301 and processor circuitry 302 also may be present (not shown in Fig. 7). Memory circuitry 301 is considered a non-transitory computer readable medium.Memory circuitry 301 may be configured to store information, e.g., control information, such as first control information and second control information, collaboration capability information, data rate information, reference signals, modulation schemes, coding schemes, first data, and / or second data in a part of the memory.Fig. 8 shows an example scenario where a technique as disclosed herein is applied.The following description presents an example scenario where a technique as disclosed herein is applied.In the following example scenario both the first wireless device and the second wireless device intend to transmit 16QAM data, i.e., K₁ = K2 = 4 and where the direct link between the first wireless device and the second wireless device (such as backhaul links) are rate-limited to R₁ = R22.The following shows how to determine the side information zk. In other words, the following shows how to construct the side information (such as feedback information) zk. A 16QAM symbol xk can for example be expressed as a linear combination of two 4QAM symbols bk1 and bk2 as xk = 2bk1 + bk2. The symbol bk2 is much less noise-resilient than the symbol bk1, since less power has been devoted to it. Therefore, the need for wireless device collaboration for transferring symbols b₁₁ and b21 may be less. Instead the wireless device collaboration may focus on reliable transfer of b12 and b22. Therefore, the first side information may be defined as Z1 = b12 and the second side information may be defined as z2 = b22 since these are the components that may need to be jointly transmitted. A simple choice for the functions f1(x1, Z2) and f2(x2, 21) may be to define them as linear combinations between data (such as symbols) and side information:f1(x1, Z2) = √V1x1 + √1 - Y₁ei122 = √Y1X1 + √1 - Y₁ei1b22f2(x2, 21) = √2x2 + √1-Y2Z1 = √Y2X2ei2 + √1-Y2ei3 b12where 0 < Yk ≤ 1. The above may for example be indicted respectively in the first control information and the second control information as disclosed herein. The above functions may be seen as the precoding functions as disclosed herein, such as the first precoding function and the second precoding function. The above function forms may be seen as the precoding function forms as disclosed herein, such as the first precoding function form and the second precoding function form.In other words, a part of the weakest symbol (such as weakest bits) of the first wireless device (e.g., the first side information z1) may be transmitted from the second wireless device (and vice versa). The stronger symbols may already be well protected and need not to be transmitted from the collaborating wireless device. The parameters yk may represent the relative amount of power that is allocated to wireless device k's own data symbol xk and the assisted wireless device's side information Z≠k (such as the collaborating wireless device's weaker symbol).Lastly, the values or may be phase values applied to create positive interference between the wireless devices.At the receiver side (e.g., the network node side), a minimal sufficient statistic may be obtained from the output of a matched filter, i.e.,r = HHy = G[f1(x1, Z2)f2(x2, 21)+ + wwhere G = HHH_ and w = HHn. It may be invoked that the standard assumption that n is white complex Gaussian noise with covariance matrix NI, and also that w may be complex Gaussian but with covariance NoG. This may imply that the only channel quantity of interest for optimizing the parameters associated to f₁(,) and f₂(,) is G. Now, any 2 × 2 Hermitian matrix can always be parameterized asG = 81+ βΙρ* √1 – β2ρ√1-β21-βwhere & is a power normalization variable. In the present disclosure, this quantity may be absorbed into the noise density No and, thus, assume 8 = 1.Thus, for given G, the network node may (e.g., to obtain optimal UL performance) solve:max I(r; b11, b12, b21, b22 G, No)¥1,2,1,2,3where I(r; b11, B12, b21, b22|G) may be the mutual information between the matched filter output r and the data symbols bnk conditioned on optimal channel state information, CSI, (such as perfect CSI) (G and No) at the receiver side. This may, unfortunately, be a challenging optimization problem. It may be challenging to obtain closed form expressions or any analytical results.It would in principle be possible to solve the above optimization and thereby obtaining optimal performance. It may however be possible to perform a simpler optimization, which improves the performance. It may be appreciated that at high signal to noise ratio, SNR, the configuration {Y1, Y2, Φ1, Φ2, 3} that maximizes the minimum Euclidean distance may also maximize I(r; b11, b12, b21, b22|G, No). The Euclidean distance problem may be equivalent to the search for the shortest vector of a lattice, which is a non-deterministic polynomial-time, NP-hard, problem.It may be appreciated that, in general, the Euclidean distance problem may not be any simpler, except for special cases for which exact results exist. This may for example be the case for small constellations and for lattice constellations. However, it has merely been suggested to consider the case of full precoding, i.e., unlimited direct link between the wireless devices (e.g., unlimited backhaul between the UEs). The Euclidean distance problem may, however, be numerically more efficient than the mutual information problem as the objective function is available in closed form.The minimum distance may be computed as:Dmin (β. ρ. γκ}, {k})=min{bnk}, {bnk}:bnk#bnk Vn,k[f₁(2511 + 512, b b22)f2(2b21+b22,612)H[f1(2b11+b12, b22) b22)Lf2(2b21+b22, b12)」[f1(2b11+b12, b22[f2(2b21 + b22, b12)[f₁(2b11 + Б12, b22)Б22,512)where the minimum distance may be dependent on the channel parameters as well as the parameters of the functions f₁(,) and f₂(,). The network node may be configured to solve:{rept}, {pppt)opty= arg max Dmin (β, ρ, γκ}, {Φκ}){Y},{k}The network node may be configured to inform the first wireless device and / or the second wireless device about the optimal values, for example in the first control information and / or the second control information as disclosed herein. The resulting minimum distance may be denoted:dmin (β,p) = Dmin (β, p. {ppt}, {pppt})kand can be compared with the corresponding minimum distance for a scenario where no wireless device collaboration and aggregation is applied:do(β,p) = Dmin (β,ρ, {1,1}, {~, $1,1), ~}).In the last expression, "~" may indicate that this value has no impact and $1,1}optimal value to use for the setting Y₁ = Y2 1.may be theFig. 8 illustrates a graph of the gain in minimum Euclidean distance for wireless device collaboration and / or aggregation (such as UE C / A) on the z-axis (in dB). The involved optimization is challenging and carried out by coordinate ascent optimization over the parameters {k}, {k}. In this example, there are no guarantees that the found solutions are optimal, but a solver has been initiated with a large number of starting positions, and it is believed that the solutions may be close to optimal. As can be seen from Fig. 8, large gains are possible, especially when β » 0. The y-axis of the graph represents the parameter β and the x-axis represents the parameter p. As a final remark, it may be mentioned that β is not necessarily indicating a difference in strength of the underlying channels. A difference in available transmit power of the two wireless devices can also be represented through β. β may represent a power imbalance between the respective channels from the first wireless device (UE1) and the second wireless device (UE2) to the network. For example, if β is 0,3333, then the first wireless device may have an uplink power of 1,33 and the second wireless device may have an uplink power of 0,6667. Thus, the first wireless device may have a channel twice as strong as the second wireless device. p may be seen as a correlation coefficient or similarity factor between the channels, assuming they are normalized to the same power. For example, with the channel between the first wireless device and the NN being [1;0], and the number of NN antennas being M=2.I follows that with p = 1, then the channel between the second wireless device and the NN may be parallel to [1;0], but its length may be unknown. It could for example be [-1,5;0] or [0,0001;0].This may be decided by β. When p = 0, then channel between the second wireless device and the NN may be orthogonal to [1;0], i.e., [0; 0,00001] or [0;-1,5].Fig. 9A shows a signaling diagram where a technique as disclosed herein is applied. Fig. 9A shows an example scenario where one-sided assistance is performed. Fig. 9A shows a signaling diagram of an example communication 700 between a radio network node 400, a first WD 300, and a second WD 300A according to this disclosure.The first wireless device 300 may transmit, to the NN 400, information 702A indicative of a collaboration capability of the first wireless device 300 and / or the second wireless device 300A.The information 702A may correspond to the information transmitted in S508 of Fig. 4A.The second wireless device 300A may transmit, to the NN 400, information 702B indicative of a collaboration capability of the first wireless device 300 and / or the second wireless device 300A.The information 702B may correspond to the information transmitted in S210 of Fig. 3A.The first wireless device 300 may transmit, to the NN 400, information 704A indicative of a first data rate (R1) of transmission from the first wireless device 300 to the second wireless device 300A via the communication link between the first wireless device 300 and the second wireless device 300A. The information 704A may correspond to the information transmitted in S510 of Fig. 4A.The second wireless device 300A may transmit, to the NN 400, information 704B indicative of a first data rate (R1) of transmission from the first wireless device 300 to the second wireless device 300A via the communication link between the first wireless device 300 and the second wireless device 300A. The information 704B may correspond to the information transmitted in S212 of Fig. 3A.The first wireless device 300 may transmit, to the NN 400, a first reference signal 706A. The first reference signal 706A may correspond to the first reference signal transmitted in S514 of Fig. 4A.The second wireless device 300A may transmit, to the NN 400, a second reference signal 706B. The second reference signal 706B may correspond to the second reference signal transmitted in S216 of Fig. 3A.The NN 400 may indicate (such as transmit information indicative of), based on the first data rate (R1) to the first wireless device 300 and / or the second wireless device 300A, which set of subcarriers 708A, 708B, to be used in the first transmission (S1) and / or the second transmission (S2). The set of subcarriers 708A, 708B, may correspond to the set of subcarriers indicated in S112 of Fig. 2A.The NN 400 transmits, to the first wireless device (UE1) 300, first control information 712. The first control information 712 corresponds to the first control information transmitted in S102 of Fig. 2A.The NN 400 transmits, to the second wireless device (UE2) 300A, second control information 710. The second control information 710 corresponds to the second control information transmitted in S110 of Fig. 2A.The NN 400 may transmit, to the first wireless device 300, a first uplink, UL, grant 714A. In one or more examples or embodiments, the first UL grant 714A may comprise the first modulation scheme and / or the first coding scheme indicated in S114 of Fig. 2B. In one or more examples or embodiments, the first UL grant 714A may carry the subcarrier information 708A, 708B.The NN 400 may transmit, to the second wireless device 300, a second uplink, UL, grant 714B.In one or more examples or embodiments, the second UL grant 714B may comprise the second modulation scheme and / or the second coding scheme indicated in S114 of Fig. 2B. In one or more examples or embodiments, the second UL grant 714B may carry the subcarrier information 708A, 708B.The first wireless device 300 may generate bits 716 from the first symbol (x1) to be transmitted to the second wireless device 300A. The bits 716 may correspond to the bits generated in S504 of Fig. 4A.The first wireless device 300 may transmit, to the second wireless device 300A over a direct link between the first wireless device 300 and the second wireless device 300A, first side information 718. The first side information 718 corresponds to the first side information z1 of S502 of Fig. 4A.Transmitting the first side information 718 may comprise providing the first side information 718 based on the generated bits 716 from the first symbol.The second wireless device 300A may process 720 the first side information (z1) 718 with the second symbol x2 for provision of second data to be sent in the second transmission 722. The processing 720 of the first side information 718 may correspond to the processing of S204 and S204A of Fig. 2A.To process 720 the first side information 718 may comprise to combining, based on the second control information, the first side information (z1) with the second symbol (x2) for provision of the second data.The second wireless device 300A transmits, in the second transmission to the network node 400, the second data 722. The second data 722 corresponds to the second data of S224 of Fig. 3B.Fig. 9B shows a signaling diagram where a technique as disclosed herein is applied. Fig. 9B shows an example scenario where two-sided assistance is performed (such as mutual assistance). Fig. 9B shows a signaling diagram of an example communication 800 between a radio network node 400, a first WD 300, and a second WD 300A according to this disclosure.The signaling diagram of Fig. 9B is similar to the signaling diagram of Fig. 9A, but where two-sided assistance is performed.The information 802A corresponds to the information 702A of Fig. 9A. The information 802B corresponds to the information 702B of Fig. 9A.The information 804A corresponds to the information 704A of Fig. 9A. The information 804B corresponds to the information 704B of Fig. 9A.The first reference signal 806A corresponds to the first reference signal 706A of Fig. 9A. The second reference signal 806B corresponds to the second reference signal 706B of Fig. 9A.The set of subcarriers 808A, 808B corresponds to the set of subcarriers 708A, 708B of Fig. 9A.The first control information 812 corresponds to the first control information 712 of Fig. 9A.The second control information 810 corresponds to the second control information 710 of Fig. 9A.The first UL grant 814A corresponds to the first UL grant 714A of Fig. 9A and the second UL grant 814B corresponds to the second UL grant 714B of Fig. 9A.The first wireless device 300 may generate bits 816A from the first symbol (x1) to be transmitted to the second wireless device 300A. The bits 816A may correspond to the bits generated in S504 of Fig. 4A. The generation of bits 816A from the first symbol corresponds to the generation of bits 716 of Fig. 9A.The second wireless device 300A may generate bits 816B from the second symbol (x2) to be transmitted to the first wireless device 300. The of bits 816B may correspond to the bits generated in S220A of Fig. 3B.The first wireless device 300 may transmit, to the second wireless device 300A over a direct link between the first wireless device 300 and the second wireless device 300A, first side information 818A. The first side information 818A corresponds to the first side information z1 of S502 of Fig. 4A.The second wireless device 300A may transmit, to the first wireless device 300 over a direct link between the first wireless device 300 and the second wireless device 300A, second side information 818B. The second side information 818B corresponds to the second side information z2 of S222 of Fig. 3B.Transmitting the first side information 818A may comprise providing the first side information 818A based on the generated bits 816A from the first symbol.The second wireless device 300A may process 820B the first side information (z1) 818A with the second symbol x2 for provision of second data to be sent in the second transmission 822B.The processing 820B of the first side information 818A may correspond to the processing of S204 and S204A of Fig. 2A.To process 820B the first side information 818A may comprise to combining, based on the second control information, the first side information (z1) with the second symbol (x2) for provision of the second data.The first wireless device 300 may process 820A the second side information (z2) 818B with the first symbol x1 for provision of first data to be sent in the first transmission 822A. The processing 820A of the second side information 818B may correspond to the processing of S516 of Fig. 4B.To process 820A the second side information 818B may comprise to combining, based on the first control information, the second side information (z2) with the first symbol (x1) for provision of the first data.The second wireless device 300A transmits, in the second transmission to the network node 400, the second data 822B. The second data 822B corresponds to the second data of S224 of Fig. 3B.The first wireless device 300 transmits, in the first transmission to the network node 400, the first data 822A. The first data 822A corresponds to the first data of S522 of Fig. 4B.Examples of methods and products (network node, first wireless device, and second wireless device) according to the disclosure are set out in the following items:Item 1. A method (100), performed by a network node, for enabling a second wireless device (UE2) to assist a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- transmitting (S102), to the first wireless device (UE1), first control information defining how first side information (z1), to be sent to the second wireless device (UE2) over a direct link between the first wireless device and the second wireless device for transmission in the second transmission (S2), is to be obtained from the first symbol (x1); and- transmitting (S110), to the second wireless device (UE2), second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (S2).Item 2. The method according to item 1, wherein the first control information indicates how to generate bits from the first symbol (x1) to be transmitted to the second wireless device, for provision of the first side information (z1) over the direct link between the first wireless device and the second wireless device.Item 3. The method according to any of the previous items, wherein the second control information comprises one or more of: a constellation mapping, a phase shift, and a power level to apply to the first side information (z1) when performing the second transmission (S2).Item 4. The method according to any of the previous items, wherein the second control information comprises information defining how to combine the first side information (z1) with the second symbol (x2), to be transmitted by the second wireless device, in the second transmission (S2).Item 5. The method according to any of the previous items, wherein the first control information comprises a first precoding function and / or a first precoding function form to apply when performing the first transmission (s1) and / or the second control information comprises a second precoding function and / or a second precoding function form to apply when performing the second transmission (s2).Item 6. The method according to any of the previous items, the method comprising:- receiving (S116), from the second wireless device, the second data transmitted in the second transmission.Item 7. The method according to any of the previous items, the method comprising:- receiving (S104), from the first wireless device and / or the second wireless device, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.Item 8. The method according to any of the previous items, the method comprising:- receiving (S106), from the first wireless device and / or the second wireless device, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- indicating (S112), based on the first data rate (R1) to the first wireless device and / or the second wireless device, which set of subcarriers to be used in the first transmission (S1) and / or the second transmission (S2).Item 9. The method according to any of the previous items, the method comprising:- receiving (S108), from the first wireless device and / or the second wireless device, a first reference signal and / or a second reference signal respectively, and- indicating (S114), to the first wireless device, a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1) and / or indicating, to the second wireless device, a second modulation scheme and / or a second coding scheme to be used in the second transmission (s2).Item 10. The method according to any of the previous items, wherein the method is for enabling the first wireless device (UE1) to assist the second transmission (S2) of the second symbol (x2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1),- wherein the second control information defines how second side information (z2), to be sent to the first wireless device (UE1) over the direct link for transmission in the first transmission (S1), is to be obtained from the second symbol (x2); and- wherein the first control information defines how to process the second side information with the first symbol (x1) for provision of first data to be sent in the first transmission (s1).Item 11. The method according to item 10, wherein the first control information comprises information indicative of the at least one first resource element and / or the second control information comprises information indicative of the at least one second resource element.Item 12. The method according to any of items 10-11, wherein the at least first resource element and the at least second resource element are the same resource.Item 13. The method according to any of items 10-12, the method comprising:- receiving (S118), from the first wireless device, the first data transmitted in the first transmission.Item 14.A method (200), performed by a second wireless device, for assisting a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- receiving (S202), from the first wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1);- receiving (S204), from a network node, second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (s2); and- transmitting (S224), in the second transmission to the network node, the second data.Item 15. The method according to any of items 14-15, the method comprising:- combining (S206), based on the second control information, the first side information (z1) with the second symbol (x2) for provision of the second data.Item 16. The method according to any of items 14-16, the method comprising:- applying (S208) a second precoding function and / or a second precoding function form when performing the second transmission (S2).Item 17. The method according to any of items 14-17, the method comprising:- transmitting (S210), to the network node, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.Item 18. The method according to any of items 14-18, the method comprising:- transmitting (S212), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- receiving (S214), from the network node, information indicating which set of subcarriers to be used in the second transmission (s2).Item 19. The method according to any of items 14-19, the method comprising:- transmitting (S216), to the network node, a second reference signal, and- receiving (S218), from the network node, information indicating a second modulation scheme and / or a second coding scheme to be used in the second transmission (s2).Item 20. The method according to any of items 14-20, wherein the method is for assisting a second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and a second symbol (x2) in at least one second resource element of a first transmission (S1) from the first wireless device (UE1), the method comprising:- obtaining (S220), based on the second control information, second side information (z2) from the second symbol (x2); and- transmitting (S222), to the first wireless device over the direct link, the second side information (z2).Item 21. The method according to item 20,:- wherein obtaining (S220) second side information (z2) comprises generating (S220A) bits from the second symbol (x2) to be transmitted to the first wireless device; and wherein- transmitting (S222) the second side information (z2) comprises providing (S222A) the second side information based on the generated bits from the second symbol (x2).Item 22.A method (500), performed by a first wireless device, for assisting a first transmission (S1) of a first symbol (x1) from the first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- transmitting (S502), to the second wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1).Item 23. The method according to item 21, the method comprising:- generating (S504) bits from the first symbol (x1) to be transmitted to the second wireless device; and wherein- transmitting (S502) the first side information comprises providing (S502A) the first side information based on the generated bits from the first symbol.Item 24. The method according to any of items 21-22, the method comprising:- applying (S506) a first precoding function and / or a first precoding function form when performing the first transmission (s1).Item 25. The method according to any of items 21-23, the method comprising:- transmitting (S508) information indicative of a collaboration capability of the first wireless device and / or the second wireless device.Item 26. The method according to any of items 21-24, the method comprising:- transmitting (S510), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- receiving (S512), from the network node, information indicating which set of subcarriers to be used in the first transmission (s1).Item 27. The method according to any of items 21-25, the method comprising:- transmitting (S514), to the network node, a first reference signal, and- receiving (S516), from the network node, information indicating a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1).Item 28. The method according to any of items 21-26, wherein the method is for assisting the second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1) from the first wireless device (UE1), the method comprising:- receiving (S518), from the second wireless device over the direct link, second side information (z2);- receiving (S520), from the network node, first control information defining how to process the second side information (z2) with the first symbol (x1) for provision of first data to be sent in the first transmission (s1); and- transmitting (S522), in the first transmission to the network node, the first data.Item 29.A network node comprising memory circuitry, processor circuitry, and a wireless interface, wherein the network node is configured to perform any of the methods according to any of items 1-13.Item 30.A second wireless device comprising memory circuitry, processor circuitry, and a wireless interface, wherein the second wireless device is configured to perform any of the methods according to any of items 14-21.Item 31.A first wireless device comprising memory circuitry, processor circuitry, and a wireless interface, wherein the first wireless device is configured to perform any of the methods according to any of items 22-28.The use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary" etc. does not imply any particular order, but are included to identify individual elements. Moreover, the use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary" etc. does not denote any order or importance, but rather the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary” etc. are used to distinguish one element from another. Note that the words "first", "second", "third" and "fourth", "primary", "secondary", "tertiary" etc. are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering. Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.It may be appreciated that the figures comprise some circuitries or operations which are illustrated with a solid line and some circuitries, components, features, or operations which are illustrated with a dashed line. Circuitries or operations which are comprised in a solid line are circuitries, components, features or operations which are comprised in the broadest example.Circuitries, components, features, or operations which are comprised in a dashed line are examples which may be comprised in, or a part of, or are further circuitries, components, features, or operations which may be taken in addition to circuitries, components, features, or operations of the solid line examples. It should be appreciated that these operations need not be performed in order presented. Furthermore, it should be appreciated that not all of the operations need to be performed. The example operations may be performed in any order and in any combination. It should be appreciated that these operations need not be performed in order presented. Circuitries, components, features, or operations which are comprised in a dashed line may be considered optional.Other operations that are not described herein can be incorporated in the example operations. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations.Certain features discussed above as separate implementations can also be implemented in combination as a single implementation. Conversely, features described as a single implementation can also be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as any sub-combination or variation of any sub-combinationIt is to be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed.It is to be noted that the words "a" or "an" preceding an element do not exclude the presence of a plurality of such elements.It is to be noted that the term "indicative of" may be seen as "associated with", "related to", "descriptive of", "characterizing", and / or "defining". The terms "indicative of", "associated with", "related to", "descriptive of", "characterizing", and "defining" can be used interchangeably. The term "indicative of" can be seen as indicating a relation. For example, weight data indicative of weight may comprise one or more weight parameters.It is to be noted that the word "based on" may be seen as "as a function of" and / or "derived from". The terms "based on" and "as a function of" can be used interchangeably. For example, a parameter determined "based on" a data set can be seen as a parameter determined "as a function of the data set. In other words, the parameter may be an output of one or more functions with the data set as an input.A function may be characterizing a relation between an input and an output, such as mathematical relation, a database relation, a hardware relation, logical relation, and / or other suitable relations.It should further be noted that any reference signs do not limit the scope of the claims, that the examples may be implemented at least in part by means of both hardware and software, and that several "means", "units" or "devices" may be represented by the same item of hardware.The various example methods, devices, nodes and systems described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Generally, program circuitries may include routines, programs, objects, components, data structures, etc. that perform specified tasks or implement specific abstract data types. Computer-executable instructions, associated data structures, and program circuitries represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.Although features have been shown and described, it will be understood that they are not intended to limit the claimed disclosure, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the scope of the claimed disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. The claimed disclosure is intended to cover all alternatives, modifications, and equivalents.

Claims

1. A method (100), performed by a network node, for enabling a second wireless device (UE2) to assist a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- transmitting (S102), to the first wireless device (UE1), first control information defining how first side information (z1), to be sent to the second wireless device (UE2) over a direct link between the first wireless device and the second wireless device for transmission in the second transmission (S2), is to be obtained from the first symbol (x1); and- transmitting (S110), to the second wireless device (UE2), second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (S2).

2. The method according to claim 1, wherein the first control information indicates how to generate bits from the first symbol (x1) to be transmitted to the second wireless device, for provision of the first side information (z1) over the direct link between the first wireless device and the second wireless device.

3. The method according to any of the previous claims, wherein the second control information comprises one or more of: a constellation mapping, a phase shift, and a power level to apply to the first side information (z1) when performing the second transmission (S2).

4. The method according to any of the previous claims, wherein the second control information comprises information defining how to combine the first side information (z1) with the second symbol (x2), to be transmitted by the second wireless device, in the second transmission (S2).

5. The method according to any of the previous claims, wherein the first control information comprises a first precoding function and / or a first precoding function form to apply when performing the first transmission (S1) and / or the second control information comprises a second precoding function and / or a second precoding function form to apply when performing the second transmission (S2).

6. The method according to any of the previous claims, the method comprising:- receiving (S116), from the second wireless device, the second data transmitted in the second transmission.

7. The method according to any of the previous claims, the method comprising:- receiving (S104), from the first wireless device and / or the second wireless device, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.

8. The method according to any of the previous claims, the method comprising:- receiving (S106), from the first wireless device and / or the second wireless device, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- indicating (S112), based on the first data rate (R1) to the first wireless device and / or the second wireless device, which set of subcarriers to be used in the first transmission (S1) and / or the second transmission (S2).

9. The method according to any of the previous claims, the method comprising:- receiving (S108), from the first wireless device and / or the second wireless device, a first reference signal and / or a second reference signal respectively, and- indicating (S114), to the first wireless device, a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1) and / or indicating, to the second wireless device, a second modulation scheme and / or a second coding scheme to be used in the second transmission (s2).

10. The method according to any of the previous claims, wherein the method is for enabling the first wireless device (UE1) to assist the second transmission (S2) of the second symbol (x2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1),- wherein the second control information defines how second side information (z2), to be sent to the first wireless device (UE1) over the direct link for transmission in the first transmission (S1), is to be obtained from the second symbol (x2); and- wherein the first control information defines how to process the second side information with the first symbol (x1) for provision of first data to be sent in the first transmission (s1).

11. The method according to claim 10, wherein the first control information comprises information indicative of the at least one first resource element and / or the second control information comprises information indicative of the at least one second resource element.

12. The method according to any of claims 10-11, wherein the at least first resource element and the at least second resource element are the same resource.

13. The method according to any of claims 10-12, the method comprising:- receiving (S118), from the first wireless device, the first data transmitted in the first transmission.

14. A method (200), performed by a second wireless device, for assisting a first transmission (S1) of a first symbol (x1) from a first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- receiving (S202), from the first wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1);- receiving (S204), from a network node, second control information defining how to process the first side information (z1) with the second symbol (x2) for provision of second data to be sent in the second transmission (s2); and- transmitting (S224), in the second transmission to the network node, the second data.

15. The method according to any of claims 14-15, the method comprising:- combining (S206), based on the second control information, the first side information (z1) with the second symbol (x2) for provision of the second data.

16. The method according to any of claims 14-16, the method comprising:- applying (S208) a second precoding function and / or a second precoding function form when performing the second transmission (S2).

17. The method according to any of claims 14-17, the method comprising:- transmitting (S210), to the network node, information indicative of a collaboration capability of the first wireless device and / or the second wireless device.

18. The method according to any of claims 14-18, the method comprising:- transmitting (S212), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- receiving (S214), from the network node, information indicating which set of subcarriers to be used in the second transmission (s2).

19. The method according to any of claims 14-19, the method comprising:- transmitting (S216), to the network node, a second reference signal, and- receiving (S218), from the network node, information indicating a second modulation scheme and / or a second coding scheme to be used in the second transmission (s2).

20. The method according to any of claims 14-20, wherein the method is for assisting a second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and a second symbol (x2) in at least one second resource element of a first transmission (S1) from the first wireless device (UE1), the method comprising:- obtaining (S220), based on the second control information, second side information (z2) from the second symbol (x2); and- transmitting (S222), to the first wireless device over the direct link, the second side information (z2).

21. The method according to claim 20:- wherein obtaining (S220) second side information (z2) comprises generating (S220A) bits from the second symbol (x2) to be transmitted to the first wireless device; and wherein- transmitting (S222) the second side information (z2) comprises providing (S222A) the second side information based on the generated bits from the second symbol (x2).

22. A method (500), performed by a first wireless device, for assisting a first transmission (S1) of a first symbol (x1) from the first wireless device (UE1), based on joint precoding of the first symbol (x1) and a second symbol (x2) of the second wireless device in at least one second resource element of a second transmission (S2) from the second wireless device (UE2), the method comprising:- transmitting (S502), to the second wireless device over a direct link between the first wireless device and the second wireless device, first side information (z1).

23. The method according to claim 21, the method comprising:- generating (S504) bits from the first symbol (x1) to be transmitted to the second wireless device; and wherein- transmitting (S502) the first side information comprises providing (S502A) the first side information based on the generated bits from the first symbol.

24. The method according to any of claims 21-22, the method comprising:- applying (S506) a first precoding function and / or a first precoding function form when performing the first transmission (s1).

25. The method according to any of claims 21-23, the method comprising:- transmitting (S508) information indicative of a collaboration capability of the first wireless device and / or the second wireless device.

26. The method according to any of claims 21-24, the method comprising:- transmitting (S510), to the network node, information indicative of a first data rate (R1) of transmission from the first wireless device to the second wireless device via the communication link between the first wireless device and the second wireless device, and- receiving (S512), from the network node, information indicating which set of subcarriers to be used in the first transmission (s1).

27. The method according to any of claims 21-25, the method comprising:- transmitting (S514), to the network node, a first reference signal, and- receiving (S516), from the network node, information indicating a first modulation scheme and / or a first coding scheme to be used in the first transmission (s1).

28. The method according to any of claims 21-26, wherein the method is for assisting the second transmission (S2) of the second symbol (x2) from the second wireless device (UE2), based on joint precoding of the first symbol (x1) and the second symbol (x2) in at least one first resource element of the first transmission (S1) from the first wireless device (UE1), the method comprising:- receiving (S518), from the second wireless device over the direct link, second side information (z2);- receiving (S520), from the network node, first control information defining how to process the second side information (z2) with the first symbol (x1) for provision of first data to be sent in the first transmission (s1); and- transmitting (S522), in the first transmission to the network node, the first data.

29. A network node comprising memory circuitry, processor circuitry, and a wireless interface, wherein the network node is configured to perform any of the methods according to any of claims 1-13.

30. A second wireless device comprising memory circuitry, processor circuitry, and a wireless interface, wherein the second wireless device is configured to perform any of the methods according to any of claims 14-21.

31. A first wireless device comprising memory circuitry, processor circuitry, and a wireless interface, wherein the first wireless device is configured to perform any of the methods according to any of claims 22-28.

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