Patent ID: 7719955

Claim:
An Orthogonal Frequency Division Multiplexing, OFDM, transmitter comprising: means for generating a set of data symbols indicative of physical layer characteristics of data transmissions from the OFDM transmitter; first symbol generating means for generating a first OFDM signalling symbol by allocating the set of data symbols to subcarriers of the first OFDM signalling symbol; second symbol generating means for generating a second OFDM signalling symbol by allocating the set of data symbols to subcarriers of the second OFDM signalling symbol, the allocation of the set of data symbols to subcarriers being different for the first OFDM signalling symbol and the second OFDM signalling symbol; and transmitter means for transmitting a message comprising the first OFDM signalling symbol and the second OFDM signalling symbol; wherein the first symbol generating means are arranged to allocate a first subset of the set of data symbols to a first subset of subcarriers of the first OFDM signalling symbol and the second symbol generating means are arranged to allocate the first subset of the set of data symbols to a second subset of subcarriers; wherein the second symbol generating means are arranged to allocate the first subset of data symbols to subcarriers having a predetermined offset relative to the first subset of carriers; wherein the second symbol generating means are arranged to allocate data symbols to subcarriers such that a data symbol of the first subset of data symbols allocated to subcarrier number n by the first symbol generating means is allocated to subcarrier number n+N, where N is a predetermined non-zero integer.