Patent ID: 7411935

Claim:
An apparatus for inclusion in a node of a wireless network, the apparatus comprising: an OFDM receiver arranged to receive packets of data from a remote node, including an analog-to-digital converter producing samples of signals received at the node from the remote node, said received signals in the form of packets of data, a packet of data including a part modulated in a pre-defined way and containing information indicative of the data rate used for at least some of the packet; an OFDM demodulator coupled to the receiver arranged to demodulate samples of the signals received at the OFDM receiver to produce demodulated signals, the samples at decision points; and an error vector magnitude calculator coupled to the receiver and to the OFDM demodulator, arranged to accept an indication of the rate as a result of the demodulator demodulating the part modulated in a pre-defined way, the error vector magnitude calculator further arranged to determine a measure of the signal quality of the decision point samples of the received signal, such that the measure of the signal quality determined by the error vector magnitude calculator is used to select a data rate for communicating between the node and the remote node, wherein the wireless network is configured to use OFDM.