Logic may implement an orthogonal frequency division multiplexing (OFDM) system operating in the one gigahertz and lower frequency bands. Logic may detect new long training sequences that are differentially orthogonal to each other for a first bandwidth mode of operation such as a one megahertz mode as well as differentially orthogonal to half of the long training sequence for a second bandwidth mode of operation such as a two megahertz or greater mode. Logic may implement two or more long training sequences for the first bandwidth mode of operation to transmit information based upon the selection of the particular long training sequence for the transmission. Logic may implement a new acknowledgement packet comprising a short training sequence and a long training sequence without a signal field and without a payload. And logic may implement bandwidth detection logic to classify a transmission based upon orthogonal properties of the long training sequences.