A communication apparatus comprising: a trigger signal generator configured to generate a trigger frame that solicits an uplink signal transmission, wherein the trigger frame comprises: - a first User Information field that comprises a first terminal identifier, ID, subfield and a first Resource Unit, RU, Allocation subfield; - a second User Information field that comprises a second terminal ID subfield and a second RU Allocation subfield; and - a third User Information field that comprises a third terminal ID subfield and a third RU Allocation subfield; and a transmitter configured to transmit the generated trigger frame, wherein a first unused value which is not to be used for a terminal ID is set to the first terminal ID subfield for Random Access, and the first RU Allocation subfield indicates a first starting RU of first one or more contiguous Random Access RUs, RA-RUs, and the first User Information field further comprises a first RA-RU Information subfield indicating a first number of RUs in the first one or more contiguous RA-RUs; and a value which is to be used for a terminal ID is set to the second terminal ID subfield for Scheduled Access; and the second RU Allocation subfield indicates a Scheduled Access RU; and a second unused value is set to the third terminal ID subfield for Random Access; and the third RU Allocation subfield indicates a second starting RU of second one or more contiguous RA-RUs, and the third User Information field further comprises a second RA-RU Information subfield indicating a second number of RUs in the second one or more contiguous RA-RUs; and the trigger frame generator is configured to set the first unused value to the terminal ID subfield for a terminal that is associated with the communication apparatus, and to set the second unused value to the terminal ID subfield for another terminal that is not associated with the communication apparatus, the second unused value being different from the first unused value. a trigger signal generator configured to generate a trigger frame that solicits an uplink signal transmission, wherein the trigger frame comprises: - a first User Information field that comprises a first terminal identifier, ID, subfield and a first Resource Unit, RU, Allocation subfield; - a second User Information field that comprises a second terminal ID subfield and a second RU Allocation subfield; and - a third User Information field that comprises a third terminal ID subfield and a third RU Allocation subfield; and - a first User Information field that comprises a first terminal identifier, ID, subfield and a first Resource Unit, RU, Allocation subfield; - a second User Information field that comprises a second terminal ID subfield and a second RU Allocation subfield; and - a third User Information field that comprises a third terminal ID subfield and a third RU Allocation subfield; and a transmitter configured to transmit the generated trigger frame, wherein a first unused value which is not to be used for a terminal ID is set to the first terminal ID subfield for Random Access, and the first RU Allocation subfield indicates a first starting RU of first one or more contiguous Random Access RUs, RA-RUs, and the first User Information field further comprises a first RA-RU Information subfield indicating a first number of RUs in the first one or more contiguous RA-RUs; and a value which is to be used for a terminal ID is set to the second terminal ID subfield for Scheduled Access; and the second RU Allocation subfield indicates a Scheduled Access RU; and a second unused value is set to the third terminal ID subfield for Random Access; and the third RU Allocation subfield indicates a second starting RU of second one or more contiguous RA-RUs, and the third User Information field further comprises a second RA-RU Information subfield indicating a second number of RUs in the second one or more contiguous RA-RUs; and the trigger frame generator is configured to set the first unused value to the terminal ID subfield for a terminal that is associated with the communication apparatus, and to set the second unused value to the terminal ID subfield for another terminal that is not associated with the communication apparatus, the second unused value being different from the first unused value.