Patent ID: 8295375
Filing Date: 2012-10-23
Classification: H04H,H04L,H04N

Abstract:
1. An apparatus for transmitting data symbols via Orthogonal Frequency Division Multiplexed (OFDM) symbols, the OFDM symbols including a plurality of data bearing sub-carriers and one or more continuous pilot sub-carrier symbols, which are located in the same position for each of the OFDM symbols and scattered pilot sub-carrier symbols, which change position between one OFDM symbol and another, in accordance with a predetermined pattern, the apparatus comprising: a modulator operable to receive the data symbols for communicating via the OFDM symbols, to form the data symbols into pairs, to generate first pairs of modulation symbols for each of the pairs of data symbols, the first pair of modulation symbols forming first and second modulation symbols of an Alamouti cell, to form a first version of the OFDM symbols by modulating the sub-carriers allocated for carrying the data with the first and second modulation symbols of the Alamouti cells, to modulate the one or more pilot carriers of the first version of the OFDM symbols, to generate second pairs of modulation symbols for each of the pairs of data symbols, the second pairs of modulation symbols forming third and fourth modulation symbols of the Alamouti cell formed for the pair of data symbols in the first version of the OFDM symbol, to form a second version of the OFDM symbols by modulating the sub-carriers allocated for carrying the data with the third and fourth modulation symbols of the Alamouti cell, to modulate the one or more pilot carriers of the second version of the OFDM symbols, and a transmitter for transmitting the first version of the OFDM symbols via a first antenna, and the second version of the OFDM symbols via a second antenna, wherein the OFDM symbols are formed with the continuous pilot symbol sub-carriers and the scattered pilot symbol sub-carriers in accordance with the predetermined pattern without pre-condition on the location of the pilot sub-carrier symbols with respect to a location of the data bearing sub-carrier symbols, such that for at least one of the pairs of data symbols, the sub-carriers, on which each of the modulation symbols of the first and second modulation symbols and the third and fourth modulation symbols forming the Alamouti cell, are separated within the first and second versions of the OFDM symbol by at least one other data bearing sub-carrier or one or more of the scattered or continuous pilot symbol sub-carriers.