A method for transmitting within a transmission bandwidth a Very High Throughput Signal Field B, VHT-SIG-B , in accordance with an IEEE 802.11ac standard in a backwards compatible preamble followed by a DATA field, by a communication device , comprising: allocating twenty signal bits (384a-384d) and six tall bits (386a-386d) for the VHT-SIG-B in the backwards compatible preamble in each 20 MHz bandwidth portion comprised within the transmission bandwidth, wherein the transmission bandwidth can be one of 20, 40, 80 or 160 MHz, the latter three comprising two, four and eight 20 MHz bandwidth portions respectively and wherein the signal bits and tails bits are repeated in each of the bandwidth portions; using a number of subcarriers for the VHT-SIG-B that is the same as a number of subcarriers for a Very High Throughput Long Training Field, VHT-LTF , and the DATA field , wherein the power scaling of the VHT-SIG-B field Is the same as for the DATA field ; applying a pilot mapping for the VHT-SIG-B that is the same as a pilot mapping for the DATA field; copying the VHT-SIG-B onto a number of space-time streams that is the same as a number of space-time streams in the DATA field for the intended user, wherein for each space-time stream the same cyclic shift diversity value is used for the VHT-SIG-B and for the DATA field; applying a long guard interval to the VHT-SIG-B which is the same as used in the preamble, and transmitting the VHT-SIG-B, wherein the backwards compatible preamble comprises a first and a second part, the first part comprising a legacy short training field , a legacy long training field , a legacy signal field , a VHT-SIG-A field being decodable by legacy devices and the second part comprising a VHT-STF , the VHT-SIG-B and the VHT-LTF and not being decodable by said legacy devices. allocating twenty signal bits (384a-384d) and six tall bits (386a-386d) for the VHT-SIG-B in the backwards compatible preamble in each 20 MHz bandwidth portion comprised within the transmission bandwidth, wherein the transmission bandwidth can be one of 20, 40, 80 or 160 MHz, the latter three comprising two, four and eight 20 MHz bandwidth portions respectively and wherein the signal bits and tails bits are repeated in each of the bandwidth portions; using a number of subcarriers for the VHT-SIG-B that is the same as a number of subcarriers for a Very High Throughput Long Training Field, VHT-LTF , and the DATA field , wherein the power scaling of the VHT-SIG-B field Is the same as for the DATA field ; applying a pilot mapping for the VHT-SIG-B that is the same as a pilot mapping for the DATA field; copying the VHT-SIG-B onto a number of space-time streams that is the same as a number of space-time streams in the DATA field for the intended user, wherein for each space-time stream the same cyclic shift diversity value is used for the VHT-SIG-B and for the DATA field; applying a long guard interval to the VHT-SIG-B which is the same as used in the preamble, and transmitting the VHT-SIG-B, wherein the backwards compatible preamble comprises a first and a second part, the first part comprising a legacy short training field , a legacy long training field , a legacy signal field , a VHT-SIG-A field being decodable by legacy devices and the second part comprising a VHT-STF , the VHT-SIG-B and the VHT-LTF and not being decodable by said legacy devices. <EOS>