Apparatus, method and computer program

Abstract

User equipment (UE) 301 receives from a network node 303 a radio resource configuration (RRC) message 310 comprising an indication to perform Digital Post Distortion (DPoD) processing of nonlinear rec

Description

TECHNICAL FIELD Various example embodiments relate generally to processing signals to reduce distortion. BACKGROUND In telecommunications networks, processing of distorted signals may be performed. In 6G, it is expected that Digital Post Distortion (DPoD) will be used to provide efficiency improvements. The digital post distortion allows the transmission of a modulation of a spectrum content in a channel bandwidth to exceed the requirements of Error Vector Magnitude (EVM) that have been used in 5G. A UE can support a network through DPoD. Transmitting with a larger EVM allows the network to optimize power amplifier (PA) efficiency, but requires assistance from UEs to apply digital post distortion to the received signal for improving the received signal quality, that has become distorted due to nonlinear effects of the Network (NW) PA transmitter. BRIEF DESCRIPTION Some example embodiments of this disclosure will be described with respect to certain aspects. These aspects are not intended to indicate key or essential features of the embodiments of this disclosure, nor are they intended to be used to limit the scope of thereof. Other features, aspects, and elements will be readily apparent to a person skilled in the art in view of this disclosure. According to a first aspect there is provided an apparatus comprises means for: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. According to some examples, the means is further for: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the means is further for: receiving, from each of the one or more user equipments, at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the means is further for: receiving, from each of the one or more user equipments, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the means is further for: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus. According to some examples, the means is further for: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and wherein the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to a second aspect, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from each of the one or more user equipments, at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from each of the one or more user equipments, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to a third aspect there is provided a method comprising: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. According to some examples, the method comprises: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the method comprises: receiving, from each of the one or more user equipments, at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the method comprises: receiving, from each of the one or more user equipments, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the method comprises: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus. According to some examples, the method comprises: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to a fourth aspect there is provided a computer readable medium comprising instructions which, when executed by a user equipment, cause the user equipment to perform at least the following: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. According to a fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by a user equipment, cause the user equipment to perform at least the following: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. According to a sixth aspect there is provided a user equipment comprising means for: receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the means is further for: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the means is further for: sending, to the network node, an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the means is further for: sending, to the network node, at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the means is further for: sending, to the network node, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the means is further for: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the means is further for: sending, to the network node, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers the user equipment will perform the DPOD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the means is further for: processing a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold; wherein the indication of whether the user equipment is capable of performing the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude threshold, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold; DPoD processing the second set of received signals to reduce an error vector magnitude of each received signal of the second set of received signals. According to a seventh aspect, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers the user equipment will perform the DPOD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: processing a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold; wherein the indication of whether the user equipment is capable of performing the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude threshold, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold; DPoD processing the second set of received signals to reduce an error vector magnitude of each received signal of the second set of received signals. According to an eighth aspect there is provided a method comprising: receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the method comprises: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the method comprises: sending, to the network node, an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the method comprises: sending, to the network node, at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams. According to some examples, the method comprises: sending, to the network node, at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the method comprises: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the method comprises: sending, to the network node, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers the user equipment will perform the DPOD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the method comprises: processing a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold; wherein the indication of whether the user equipment is capable of performing the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude threshold, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold; DPoD processing the second set of received signals to reduce an error vector magnitude of each received signal of the second set of received signals. According to a ninth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to a tenth aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipmentreceiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to an eleventh aspect there is provided an apparatus comprising means for: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. According to some examples, the means is further for: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the means is further for: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus. According to some examples, the means is further for: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and wherein the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to some examples, the means is further for: sending a radio resource configuration setup or reconfiguration message to the group of user equipments before determining the at least one user equipment. According to some examples, the means is further for: determining that a trigger condition has been satisfied, and in response sending the medium access control message to the at least one user equipment. According to a twelfth aspect, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and wherein the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending a radio resource configuration setup or reconfiguration message to the group of user equipments before determining the at least one user equipment. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: determining that a trigger condition has been satisfied, and in response sending the medium access control message to the at least one user equipment. According to a thirteenth aspect there is provided a method comprising: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. According to some examples, the method comprises: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for; an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the respective user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the respective user equipment can perform the DPoD processing for. According to some examples, the method comprises: receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing. According to some examples, the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus performing the method. According to some examples, the method comprises: receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to some examples, the distortion metric comprises an error vector magnitude. According to some examples, the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and wherein the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold. According to some examples, the method comprises: sending a radio resource configuration setup or reconfiguration message to the group of user equipments before determining the at least one user equipment. According to some examples, the method comprises: determining that a trigger condition has been satisfied, and in response sending the medium access control message to the at least one user equipment. According to a fourteenth aspect there is provided a computer readable medium comprising instructions which, when executed by a user equipment, cause the user equipment to perform at least the following: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. According to a fifteenth aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by a user equipment, cause the user equipment to perform at least the following: determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment; sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. According to a sixteenth aspect there is provided a user equipment comprising means for: receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the means is further for: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the means is further for: sending, to the network node, a medium access control message comprising an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user can equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the means is further for: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the means is further for: sending, to the network node, a medium access control message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the medium access control message comprises an indication of which carriers the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to a seventeenth aspect, there is provided a user equipment comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of nonlinear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, a medium access control message comprising an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user can equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the instructions, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the network node, a medium access control message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the medium access control message comprises an indication of which carriers the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to an eighteenth aspect there is provided a method comprising: receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to some examples, the method comprises: determining processing resources of the user equipment to perform the DPoD processing. According to some examples, the method comprises: sending, to the network node, a medium access control message comprising an indication of whether the user equipment is capable of performing the DPoD processing. According to some examples, the indication comprises at least one of: an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction; an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction; an indication of a maximum number of streams that the user equipment can perform the DPoD processing for; an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams; an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams; an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams; an indication of a Multiple Input Multiple Output rank that the user can equipment can perform the DPoD processing for. According to some examples, the indication comprises at least one of: an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for; an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for. According to some examples, the method comprises: sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing. According to some examples, the method comprises: sending, to the network node, a medium access control message confirming that resources have been assigned by the user equipment for the DPoD processing. According to some examples, the medium access control message comprises an indication of which carriers the user equipment will perform the DPoD processing for. According to some examples, the DPoD processing reduces a distortion metric of the received signals. According to a nineteenth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of non-linear received signals at the user equipment,; performing the DPoD processing of the non-linear signal. According to a twentieth aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of non-linear received signals at the user equipment; receiving a non-linear signal; performing the DPoD processing of the non-linear signal. According to an aspect, there is provided a computer readable medium comprising program instructions stored thereon for performing at least one of the above methods. According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least one of the above methods. According to an aspect, there is provided a non-volatile tangible memory medium comprising program instructions stored thereon for performing at least one of the above methods. According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method according to any of the preceding aspects. In the above, many different embodiments have been described. It should be appreciated that further embodiments may be provided by the combination of any two or more of the embodiments described above. LIST OF THE DRAWINGS In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which Fig. 1 shows an example of a communication network to which examples disclosed herein may be applied; Fig. 2 show an example of a signaling flow diagram; Fig. 3 shows an example of a method flow; Fig. 4 shows, an example of a method flow; Fig. 5 show an example of a signaling flow diagram; Fig. 6 shows an example method; Fig. 7 shows an example method; Fig. 8 shows an example method; Fig. 9 shows an example method; and Fig. 10 shows an example of an apparatus. DESCRIPTION OF EMBODIMENTS The following embodiments are exemplary. Although the specification may refer to “an" "one", or “some" embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment's), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Further, when a particular feature, structure, or characteristic is described in connection of an embodiment, it is within the knowledge of one skilled in the art to apply such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. It shall be understood that although the terms "first," "second" and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Examples described herein relate to processing of signals. The signals maybe received as distorted or "non-Linear". The processing may make the signals more linear, i.e., less distorted. The processing may comprise DPoD. Downlink DPoD (where DPoD is applied by a UE to signals received from a network node such as a base station (BTS)) allows for higher BTS transmission (Tx) EVM, which allows for increased power efficiency with minimal effect on Block Error Rate (BLER) and / or throughput, but at the cost of higher UE implementation complexity. This is because the DPoD is applied at the UE. DPoD can be used to process non-linear signals at the receiver side to mitigate transmitter PA nonlinearity (e.g., distortion). DPoD is discussed in Rl-2212129, in particular in Figure 13. Some examples described herein provide a method for indicating capability of UE to support DPoD. Some examples provide a method for the activation of the DPoD procedure. Some examples provide methods for application of DPoD towards a UE with 6G architecture. Carrier Aggregation (GA), Dual Carrier (DC) and / or 4-to-8-layer DL Multiple Input Multiple Output (MIMO). In some of these examples, 6G UEs will exceed 28 parallel downlink streams that is found in some of the most advanced 5G designs. For the purposes of the present disclosure, the phrases "at least one of A or B”, “at least one of A and B”, and "A and / or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and / or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Embodiments described may be implemented in a communication network, such as any of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, and enhanced LTE (eLTE), 5G (also called NR), or any future RAT such as 6G. Moreover, communication within the communication network may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple-Input Multiple-Output (MIMO), Orthogonal Frequency Division Multiple (OFDM), and / or Discrete Fourier Transform spread OFDM (DFT-s-OFDM). As used herein, the term "network device" or "network node" refers to a node in a communication network via which user equipment may access the network and / or which is capable of controlling radio communication and managing radio resources within a cell. The network node or network device may be referred to as a base station (BS), an access point (AP) or an access node. The network device may be, depending on the applied technology, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also referred to as a gNB), a Remote Radio Unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, an Integrated Access and Backhaul (LAB) node, a low power node, a non-terrestrial network (NTN) or non-ground network device such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous earth orbit (GEO) satellite, or an aircraft network device. Moreover, in connection of split radio access network (RAN), the network device may refer to a centralised unit (CU) of a base station and / or a distributed unit (DU) of a base station. An interface between CU and DU may be referred to as an Fl interface in NR. In the split RAN architecture, node operations may be carried out, at least partly, in the central / centralized unit, CU, (e.g. server, host or node) operationally coupled to the DU, (e.g. a radio head / node). One CU may control one or more DUs, acting at least as transmit / receive (Tx / Rx) nodes. In some embodiments, the DUs may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the CU may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. In practice, any processing task may be performed in either the CU or the DU and the boundaiy where the responsibility is shifted between the CU and the DU may depend on the applied implementation. The term "terminal device" refers to any end device that may be capable of wireless communication. By way of example, a terminal device may be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), or a Mobile Station (MS). The terminal device may include a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, USB dongles, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts], a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. A term "resource”, as used herein, may refer to radio resources in time domain, in frequency domain, in space domain, and / or in code domain. Some examples of resources include e.g. a physical resource block (PRE), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term "transmission” and / or "reception” may refer to wirelessly transmitting and / or receiving via a wireless propagation channel on radio resources. Fig. 1 illustrates an example of a communication network to which examples disclosed herein may be applied. The communication network or a cellular communication network may comprise a network node 110 providing one or more cells, such as cell 100, and a network node 112 providing one or more other cells, such as cell 102. Each cell may be, e.g., a macro cell, a micro cell, femto, or a pico cell, for example. The cell may define a coverage area or a service area of the corresponding access node. The network node 110 may provide a user equipment (UE) 120 (one or more UEs) with wireless access to the communication network. The wireless access may comprise downlink (DL) communication from the network node to the UE 120 and uplink (UL) communication from the UE 120 to the network node. Examples of uplink channels comprise physical uplink control channel (PUCCH) for transmitting control information and physical uplink shared channel (PUSCH) for transmitting data towards the network. Examples of downlink channels comprise physical downlink control channel (PDCCH) for transmitting control information and physical downlink shared channel (PDSCH) for transmitting data towards the user equipment. There may be a plurality of UEs 120, 122 in the system. Each of them may be served by the same or by different network nodes 110, 112. UE may be configured with dual connectivity (DC), wherein the UE, e.g. UE 120, may be connected to multiple network nodes 110, 112. The UEs 120, 122 may communicate with each other, in case device-to-device (D2D) communication interface is established between them via a so-called sidelink (SL). Such D2D communications may be referred to as machine-to-machine, peer-to-peer (P2P) communications, or ve-hicle-to-vehicle (V2V), for example. In the case of multiple network nodes in the communication network, the network nodes may be connected to each other via an interface. LTE specifications call such an interface as X2 interface. An interface between an LTE node and a 5G node, or between two 5G nodes may be called Xn interface. The network nodes 110 and 112 may be further connected via another interface to a core network 116 of the communication network. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise e.g. a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to / from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC). The 5G core may comprise e.g. an access and mobility management function (AMF) and a user plane function / gateway (UPF) and other functions. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering &integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing and forwarding, packet inspection and quality of service (QoS) handling, for example. A UE may assist the NW with energy efficiency improvements achieved through DPoD feature support at the UE in the downlink. This requires additional baseband receiver processing, for example Fast Fourier Transform Hardware (FFT HW) processing of each downlink stream the UE receives. There is a limit to how many additional parallel signal streams the UE can manage for DL power efficiency improvement methods. As such, neither the NW nor the UE has the information or a protocol for exchanging the information of UE DPoD parallel streams. The problem is illustrated in Figure 2. Figure 2 shows a network 203 comprising a base station 207 (e.g., gNB) and a UE 201. UE 201 may receive multiple data streams from base station 207 on DL frequency bands. UE 201 may receive data streams over DL bands that are MIMO, CA and / or DC. UE 201 maybe limited in capability as to how many streams it can apply DPoD to. In some examples below, UE capability limitations are indicated to a network node. According to the capability exchange: The NW is informed of each UE capability to support a finite number of DPoD parallel processes. - The UE can trade off supported downlink streams (CA / DC, MIMO) with parallel DPoD processes. The NW and UE can further the activation procedure to consider UE limitation and select only the most critical streams for DPoD. The NW can use the information of each UE to plan DPoD relative to multi-rx, so that it can distribute DPoD streams between UEs. - The NW can decide between supported bands, band-combinations, MIMO streams (using Rank Indicator (RI)) to apply optimization and energy efficiency at the most critical streams. Figure 3 shows an example method flow for setting up DPoD between UE 301 and network 303. Network 303 may comprise a network node, such as a base station (e.g., gNB, eNB) for example. At 302, UE 301 sends capability information including an indication that UE 301 supports DPoD to network 303. In 304 and 306, additional information relevant to DPoD is also exchanged to provide information on parameters for the DPoD. This allows higher granularity of application of the DPoD scheme, with dependency on the UE processing capabilities. At 304, UE 301 indicates capability information to network 303. The capability information may comprise a maximum number of Downlink and / or Uplink DPoD streams. The capability information may comprise an indication of support for at least one of CA, DC or MIMO. Processing at UE 301 can be used to reduce EVM of received signals. The processing may include DPoD. Examples of information that may be included in the capability information sent from user equipment 301 to network 301 include at least one of: • an indication of whether the user equipment 301 can perform the processing for signals received in a downlink direction; • an indication of whether user equipment 301 can perform the processing for signals received in an uplink direction; • an indication of a maximum number of streams that user equipment 301 can perform the processing for; • an indication of whether user equipment 301 can perform the processing for CA data streams; • an indication of whether user equipment 301 can perform the processing for DC data streams; • an indication of whether user equipment 301 can perform the processing for MIMO data streams; • an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that user equipment 301 can perform the processing for; • an indication of a maximum total number MIMO data streams that user equipment 301 can perform the processing for; • an indication of a MIMO rank that user equipment 301 can perform the processing for. At 306, a support data field may optionally he added and sent to network 303. The support data field may indicate which band combination is supported by UE 301 for DPoD. Downlink carriers and DPoD assistance may consume similar FFT processing power at the UE, hence granularity of the DPoD support feature can be mapped into UE 301's band combination lists. It is understood that a higher amount of simultaneous DPoD processes lowers the number of simultaneous carriers a UE may have in downlink CA, DC or MIMO. At 308, network 303 makes a combined evaluation between active UEs within the cell or within locations where the network 303 needs energy efficiency enhancements. Network 303 may then schedule DPoD usage between the active UEs on a per stream (carrier) basis. The scheduling may take into account the capability information received at 302, 304 and 306. The scheduling may also take into account the information to be sent to each active UE. Network 303 may determine, at 308, at least one user equipment to perform processing of non-linear received signals at each of the at least one user equipment. The processing may reduce an EVM of the received signals. The processing comprises Digital Post Distortion, DPoD, processing. The at least one user equipment may be determined from a group of user equipments. At 310, a radio resource configuration (RRC) message is sent from network 303 to UE 301 to setup or reconfigure UE 301. The message may optionally comprise an indication carrying the assignment of DPoD, which can be in a per carrier resolution. The indication may comprise an indication to perform processing to reduce EVM of received signal(s) for one or more data streams. In some examples, the indication may indicate to perform processing to reduce EVM for received signals having an EVM value below a threshold value. At 312, UE 301 evaluates the DPoD assignmentsentat 310. UE 301 may then dedicate processing for receivers, which may include processing for DPoD. At 314, UE 301 acknowledges the DPoD assignment, which may optionally be in a per carrier resolution. The acknowledgment may be sent in a RRC message from UE 301 to network 303. The RRC message may indicate which of the carriers UE 301 will perform the processing for. In some examples, more than one UE may perform the method performed by UE 301 in Figure 3. Figure 4 shows second example method flow for setting up DPoD between UE 401 and network 403. Network 403 may comprise a network node, such as a base station (e.g., gNB, eNB) for example. 402, 402, 406 and 408 may correspond to 302, 304, 306 and 308 respectively. At 416, an RRC setup or reconfiguration message may be sent from network 404 to UE 401. At 418, network 404 determines that a trigger for improving efficiency has been activated. At 420, a Medium Access Control (MAC) Control Element (CE) is sent from network 403 to UE 401 to activate DPoD. The MAC CE may optionally comprise an indication carrying the assignment of DPoD, which can be in a per carrier resolution. In some examples, the DPoD assignment may be per MIMO layer. The indication may comprise an indication to perform processing to reduce EVM of received signal(s) for one or more data streams. In some examples, the indication may indicate to perform processing to reduce EVM for received signals having an EVM value below a threshold value. At 422, UE 401 evaluates the DPoD assignment sent at 310. UE 301 may then dedicate processing for receivers, which may include processing for DPoD. At 424, UE 401 sends a MAC CE to confirm the DPoD assignment received at 420. The MAC CE may indicate which of the carriers and / or MIMO layers that UE 401 will perform the processing for. In some examples, more than one UE may perform the method performed by UE 401 in Figure 4. Figure 5 shows an example where a network 503 can use base station 507 to assign DPoD processing for certain DL bands to UEs 501a and 501b. The DPoD processing may be applied per carrier and / or per MIMO stream using the methods of Figures 3 and 4. Figure 6 shows a method flow diagram. The method may be performed by a network node, such as network node 303, for example. At 600, the method comprises determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment. At 602, the method comprises sending, the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing. Figure 7 shows a method flow diagram. The method may be performed by a user equipment, such as user equipment 301 for example. At 700, the method comprises receiving, from a network node, a radio resource configuration message comprising an indication to perform DPoD processing of non-linear received signals at the user equipment. At 702, the method comprises receiving a non-linear signal. At 704, the method comprises performing the DPoD processing of the non-linear signal. Figure 8 shows a method flow diagram. The method may be performed by a network node, such as network node 403 for example. At 800, the method comprises determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment. At 802, the method comprises sending, to the at least one user equipment, a medium access control message comprising an indication to perform the DPoD processing. Figure 9 shows a method flow diagram. The method may be performed by a user equipment, such as user equipment 401, for example. At 900, the method comprises receiving, from a network node, a medium access control message comprising an indication to perform Digital Post Distortion, DPoD, processing of non-linear received signals at the user equipment, wherein the processing reduces an error vector magnitude of the received signals. At 902, the method comprises receiving a non-linear signal. At 904, the method comprises performing the DPoD processing of the non-linear signal. Fig. 10 shows, by way of example, a block diagram of an apparatus 10. The apparatus 10 comprises, for example, at least one processor 12 and at least one memory 14 storing instructions 15 that, when executed by the at least one processor, cause the apparatus 10 at least to perform the method or methods as disclosed herein, and any of the embodiments thereof. In an example, the at least one memory and the instructions (e.g. a computer program code, software), are configured, with the at least one processor, to cause the apparatus 10 to perform the method or methods as disclosed herein, and any of the embodiments thereof. A processor 12 may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware cir-cuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessors) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitiy applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. The memory 14 may be implemented using any suitable data storage technology. The memory may comprise a database for storing data. The memory 14 may be at least in part external to apparatus 10 but accessible to apparatus 10. The instructions 15 may be comprised in a computer readable medium or a non-transitory computer readable medium. A term non-transitory, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. random access memory, RAM, vs. read only memory, ROM). For example, the apparatus 10 is a terminal device, such as the UE of Fig. 1 to 4. As another example, the apparatus is comprised in such a terminal device, e.g. as a chipset configured to control the terminal device. The apparatus 10 may be caused or configured to perform at least the method of Fig. 7 or 9 and / or any one or more of the embodiments described. As another example, the apparatus 10 is a network node, e.g. the network node of Fig. 1 to 4. In another embodiment, the apparatus is comprised in such a network node, e.g. as a chipset configured to control the network node. The apparatus 10 may be caused or configured to perform at least the method of Fig. 6 or 8 and / or any one or more of the embodiments described. The apparatus may comprise one or more entities of any of protocol layers, such as a MAC entity, an RRC entity, an RLC entity, a PDCP entity or a PHY entity. In some embodiments, the entity is configured to perform at least the method of Fig. 6 or Fig. 8, and / or any one or more of the embodiments described. The apparatus 10 comprises a radio interface 16. The radio interface 16 may provide the apparatus 10 with communication capabilities. The radio interface 16 may comprise a receiver configured to receive information in accordance with at least one cellular or non-cellular standard. The radio interface 16 may comprise a transmitter configured to transmit information in accordance with at least one cellular or non-cellular standard. The receiver may comprise more than one receiver. The transmitter may comprise more than one transmitter. The radio interface 16 may comprise a transceiver configured to receive and transmit information in accordance with at least one cellular or non-cellular standard. The transceiver may comprise more than one transceiver. The apparatus 10 may comprise a user interface 18 comprising, for example, at least one of a keypad, a microphone, a touch display, a display, a speaker, etc. The user interface 18 may be used to control the apparatus by the user. The user interface 18 may be external to the apparatus 10. For example, the apparatus 10 may be connected to another device, such as a computer, either via wireless or wired connection, and the apparatus 10 is controlled by the user via the computer. In an embodiment, at least some of the processes described herein may be carried outby an apparatus comprising means for carrying out at least some of the described processes. Means for performing method steps as disclosed herein may include software and / or hardware components of the apparatus 10. For example, the at least one processor 12, the memory 14, and the computer program code form means for carrying out the method or methods as disclosed herein, and any of the embodiments thereof. As used herein the term “means” is to be construed in singular form, i.e. referring to a single element, or in plural form, i.e. referring to a combination of single elements. Therefore, terminology “means for [performing A, B, C]", is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology “means for performing A, means for performing B, means for performing C" is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

1. An apparatus comprising means for:determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment;sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing.

2. The apparatus according to claim 1, wherein the means is further for: receiving, from one or more user equipments of the group of user equipments, an indication of whether each of the one or more user equipments are capable of performing the DPoD processing.

3. The apparatus according to claim 2, wherein the means is further for: receiving, from each of the one or more user equipments, at least one of:an indication of whether the respective user equipment can perform the DPoD processing for signals received in a downlink direction;an indication of whether the respective user equipment can perform the DPoD processing for signals received in an uplink direction;an indication of a maximum number of streams that the respective user equipment can perform the DPoD processing for;an indication of whether the respective user equipment can perform the DPoD processing for Carrier Aggregation data streams;an indication of whether the respective user equipment can perform the DPoD processing for Dual Connectivity data streams;an indication of whether the respective user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams.

4. The apparatus according to claim 2 or claim 3, wherein the means is further for:receiving, from each of the one or more user equipments, at least one of:an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams thatthe respective user equipment can perform the DPoD processing for;an indication of a maximum total number of Multiple Input Multiple Output data streams thatthe respective user equipment can perform the DPoD processing for.5 The apparatus according to any of claims 2 to 4, wherein the means is further for:receiving, from each of the one or more user equipments, an indication of which band combination is supported by the respective user equipment for the DPoD processing.

6. The apparatus according to any of claims 2 to 5, wherein the determining the at least one user equipment to perform the DPoD processing of non-linear received signals at each of the at least one user equipment is based on: at least one of the indications received from the one or more user equipments; data to be sent to the at least one user equipment from a network comprising the apparatus.

7. The apparatus according to any preceding claim, wherein the means isfurther for:receiving, from a user equipment of the at least one user equipment, a message confirming that resources have been assigned by the user equipment for the DPoD processing.

8. The apparatus according to claim 7, wherein the message comprises an indication of which carriers of the received signals that the user equipment will perform the DPoD processing for.

9. The apparatus according to any preceding claim, wherein the DPoD processing reduces a distortion metric of the received signals.

10. The apparatus according to claim 9, wherein the distortion metric comprises an error vector magnitude.

11. The apparatus according to any preceding claim, wherein the at least one user equipment receives and processes a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold, and wherein the indication to perform the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold.

12. A method comprising:determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment;sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing.

13. A computer program comprising instructions for an apparatus stored thereon for performing at least the following:determining, from a group of user equipments, at least one user equipment to perform Digital Post Distortion, DPoD, processing of non-linear received signals at each of the at least one user equipment;sending, to the at least one user equipment, a radio resource configuration message comprising an indication to perform the DPoD processing.

14. A user equipment comprising means for:receiving, from a network node, a radio resource configuration message comprising an indication to perform Digital Post Distortion, DPoD, processing of nonlinear received signals at the user equipment;receiving a non-linear signal;performing the DPoD processing of the non-linear signal.

15. The user equipment according to claims 14, wherein the means is further for:determining processing resources of the user equipment to perform the DPoD processing.

16. The user equipment according to claim 14 or claim 15, wherein the means is further for:sending, to the network node, an indication of whether the user equipment is capable of performing the DPoD processing.

17. The user equipment according to claim 16, wherein the means is further for:sending, to the network node, at least one of:an indication of whether the user equipment can perform the DPoD processing for signals received in a downlink direction;an indication of whether the user equipment can perform the DPoD processing for signals received in an uplink direction;an indication of a maximum number of streams that the user equipment can perform the DPoD processing for;an indication of whether the user equipment can perform the DPoD processing for Carrier Aggregation data streams;an indication of whether the user equipment can perform the DPoD processing for Dual Connectivity data streams;an indication of whether the user equipment can perform the DPoD processing for Multiple Input Multiple Output data streams.

18. The user equipment according to claim 16 or claim 17, wherein the means is further for:sending, to the network node, at least one of:an indication of a maximum total number of Carrier Aggregation data streams and / or Dual Connectivity data streams that the user equipment can perform the DPoD processing for;an indication of a maximum total number of Multiple Input Multiple Output data streams that the user equipment can perform the DPoD processing for.

19. The user equipment according to claim 17 or claim 18, wherein the means is further for:sending, to the network node, an indication of which band combination is supported by the user equipment for the DPoD processing.

20. The user equipment according to any of claims 14 to 19, wherein the means is further for:sending, to the network node, a message confirming that resources have been assigned by the user equipment for the DPoD processing.

21. The user equipment according to claim 20, wherein the message comprises an indication of which carriers the user equipment will perform the DPOD processing for.

22. The user equipment according to any of claims 14 to 21, wherein the the DPoD processing reduces a distortion metric of the received signals.

23. The user equipment according to claim 22, wherein the distortion metric comprises an error vector magnitude.

24. The user equipment according to claim 14 to claim 23, wherein the means is further for:processing a first set of received signals each having an error vector magnitude that is less than a first error vector magnitude threshold;wherein the indication of whether the user equipment is capable of performing the DPoD processing comprises an indication to receive and process a second set of received signals each having an error vector magnitude that is less than a second error vector magnitude threshold, wherein the second error vector magnitude threshold is larger than the first error vector magnitude threshold;DPoD processing the second set of received signals to reduce an error vector magnitude of each received signal of the second set of received signals.

25. A method comprising:receiving, from a network node, a radio resource configuration message comprising an indication to perform Digital Post Distortion, DPoD, processing of nonlinear received signals at a user equipment;receiving a non-linear signal;performing the DPoD processing of the non-linear signal.

26. A computer program comprising instructions for a user equipment stored thereon for performing at least the following:receiving, from a network node, a radio resource configuration message comprising an indication to perform Digital Post Distortion, DPoD, processing of nonlinear received signals at the user equipment;receiving a non-linear signal;performing the DPoD processing of the non-linear signal.

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