A method performed in a network access node of an LTE-A communications system, comprising: when in a time division duplex mode of operation with a user equipment, allocating, physical uplink control channel resources by reserving physical uplink control channel format la/lb resources for at least one acknowledge/negative acknowledge bundle, wherein a number of physical uplink control channel format la/lb resources are allocated to the user equipment for each of the at least one acknowledge/negative acknowledge bundle, sending an indication of the allocated physical uplink control channel format la/lb resources reserved to the user equipment, receiving from the user equipment in an uplink as a response to received data in a downlink, at least one acknowledge/negative acknowledge bundle comprising a set of at least one time division duplex subframe and at least one component carrier that are configured to form a subset of acknowledge/negative acknowledge feedback, wherein the subset of acknowledge/negative acknowledge feedback is received from the user equipment in the uplink as a response to data received by the user equipment in the downlink, and wherein the acknowledge/negative acknowledge bundle is received on one of the allocated physical uplink control channel format la/lb resources which depends on the value of a downlink assignment index of the physical downlink control channel last received by the user equipment, wherein a position of the allocated physical uplink control channel format la/lb resources of the user equipment is determined in accordance with one of: ƒ UE para RA index = N PUCCH + M ⋅ UE para + RA index mod C, or ƒ UE para RA index = N PUCCH + M ⋅ UE para + RA index mod C, where UE para is a user equipment specific parameter; and RA index = 1,...,M, where M is a total number of physical uplink control channel format la/lb resources allocated to the user equipment, and M corresponds to a number of ACK/NACK bundles, "·" means a "multiply" operation, "mod" is modulo, and where N PUCCH and C are values defined by a physical uplink control channel resource allocation unit of the network access node when in a time division duplex mode of operation with a user equipment, allocating, physical uplink control channel resources by reserving physical uplink control channel format la/lb resources for at least one acknowledge/negative acknowledge bundle, wherein a number of physical uplink control channel format la/lb resources are allocated to the user equipment for each of the at least one acknowledge/negative acknowledge bundle, sending an indication of the allocated physical uplink control channel format la/lb resources reserved to the user equipment, receiving from the user equipment in an uplink as a response to received data in a downlink, at least one acknowledge/negative acknowledge bundle comprising a set of at least one time division duplex subframe and at least one component carrier that are configured to form a subset of acknowledge/negative acknowledge feedback, wherein the subset of acknowledge/negative acknowledge feedback is received from the user equipment in the uplink as a response to data received by the user equipment in the downlink, and wherein the acknowledge/negative acknowledge bundle is received on one of the allocated physical uplink control channel format la/lb resources which depends on the value of a downlink assignment index of the physical downlink control channel last received by the user equipment, wherein a position of the allocated physical uplink control channel format la/lb resources of the user equipment is determined in accordance with one of: ƒ UE para RA index = N PUCCH + M ⋅ UE para + RA index mod C, or ƒ UE para RA index = N PUCCH + M ⋅ UE para + RA index mod C, where UE para is a user equipment specific parameter; and RA index = 1,...,M, where M is a total number of physical uplink control channel format la/lb resources allocated to the user equipment, and M corresponds to a number of ACK/NACK bundles, "·" means a "multiply" operation, "mod" is modulo, and where N PUCCH and C are values defined by a physical uplink control channel resource allocation unit of the network access node UE para is a user equipment specific parameter; and RA index = 1,...,M, where M is a total number of physical uplink control channel format la/lb resources allocated to the user equipment, and M corresponds to a number of ACK/NACK bundles, "·" means a "multiply" operation, "mod" is modulo, and where N PUCCH and C are values defined by a physical uplink control channel resource allocation unit of the network access node