frequency spectrum within any stream there are data packets that contain both payload data and a preamble simultaneous multiple stream transmission leads to higher bandwidth to achieve simultaneity each data stream is spatially pre coded and then transmitted through a different transmit antenna this spatial pre coding and processing is done by block 210 this results in a sequence of code symbols which are mapped to a signal group to produce a sequence of modulation symbols the mimo system may support a number of modulation schemes including orthogonal frequency division multiplexing ofdm is a spread spectrum technique it distributes data over a number of sub carriers spaced apart at precise frequencies the spacing is orthogonal and enables a receiver to recover data this modulation technique may be employed using any wireless standard including 802 11ac vht the ofdm modulator 205 splits the modulation symbols into a number of parallel streams an inverse fft is performed on each set of sub carrier to produce time domain ofdm symbols the ofdm symbols are distributed in the payloads of multiple data packet a preamble is carried along with the payload in each data packet the preamble comprises several symbols which are split into parallel streams similar to data the preamble is appended to the data payload prior to spatial processing different spatial streams are transmitted through a plurality of antennas using rf transceivers 225 the transmitted information is received on a plurality of.