A method comprising: transmitting, by a base station (101, 102, 103) to a User Equipment, UE, (111, 112, 113, 114, 115, 116) via higher layer signalling, information indicating a first Time Division Duplexing, TDD, UpLink-DownLink, UL-DL, configuration, wherein a TDD UL-DL configuration is defined over a time period of ten Subframes that comprise DL subframes where a communication direction is from the base station to the UE, UL subframes where a communication direction is from the UE to the base station, and special subframes where a communication direction can be both from the base station to the UE and from the UE to the base station, and wherein each subframe of the ten subframes has a unique time domain index; a control channel conveying a DL Control Information, DCI, format indicating a second TDD UL-DL configuration; and configuration information for the UE to periodically transmit a first Sounding Reference Signal, SRS, in a first UL subframe of the first TDD UL-DL configuration using a first set of SRS transmission parameters, wherein in response to receiving the information indicating the first TDD UL-DL configuration, the DCI format indicating the second TDD UL-DL configuration, and the configuration information, the UE transmits the first SRS in the first UL subframe of the first TDD UL-DL configuration when the first UL subframe is an UL subframe in the second TDD UL-DL configuration and suspending transmission by the UE of the first SRS in the first UL subframe of the first TDD UL-DL configuration when the first UL subframe is a DL subframe in the second TDD UL-DL configuration. transmitting, by a base station (101, 102, 103) to a User Equipment, UE, (111, 112, 113, 114, 115, 116) via higher layer signalling, information indicating a first Time Division Duplexing, TDD, UpLink-DownLink, UL-DL, configuration, wherein a TDD UL-DL configuration is defined over a time period of ten Subframes that comprise DL subframes where a communication direction is from the base station to the UE, UL subframes where a communication direction is from the UE to the base station, and special subframes where a communication direction can be both from the base station to the UE and from the UE to the base station, and wherein each subframe of the ten subframes has a unique time domain index; a control channel conveying a DL Control Information, DCI, format indicating a second TDD UL-DL configuration; and configuration information for the UE to periodically transmit a first Sounding Reference Signal, SRS, in a first UL subframe of the first TDD UL-DL configuration using a first set of SRS transmission parameters, a control channel conveying a DL Control Information, DCI, format indicating a second TDD UL-DL configuration; and configuration information for the UE to periodically transmit a first Sounding Reference Signal, SRS, in a first UL subframe of the first TDD UL-DL configuration using a first set of SRS transmission parameters, wherein in response to receiving the information indicating the first TDD UL-DL configuration, the DCI format indicating the second TDD UL-DL configuration, and the configuration information, the UE transmits the first SRS in the first UL subframe of the first TDD UL-DL configuration when the first UL subframe is an UL subframe in the second TDD UL-DL configuration and suspending transmission by the UE of the first SRS in the first UL subframe of the first TDD UL-DL configuration when the first UL subframe is a DL subframe in the second TDD UL-DL configuration.