Transmitting apparatus and method, and receiving apparatus and method
First Claim
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, anda 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.
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Accused Products
Abstract
A method of transmitting data symbols via Orthogonal Frequency Division Multiplexed (OFDM) symbols, that includes forming data symbols into pairs, generating a first pair of modulation symbols for each of the pairs of data symbols, forming a first version of the OFDM symbols by modulating the sub-carriers allocated for carrying the data with the first and second modulation symbols, and modulating the one or more pilot carriers of the first version of the OFDM symbol. The method also includes generating a second pair of modulation symbols for each of the pairs of data symbols, forming a second version of the OFDM symbol by modulating the sub-carriers allocated for carrying the data with the third and fourth modulation symbols, modulating the one or more pilot carriers of the second version of the OFDM symbols and transmitting the first version of the OFDM symbol, and the second version of the OFDM symbol.
23 Citations
16 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of 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 to another, in accordance with a predetermined pattern, the method comprising:
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receiving data symbols for communicating via the OFDM symbols, forming the data symbols into pairs, generating a first pair 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, forming a first version of the OFDM symbols by modulating the sub-carriers allocated for carrying the data with the first pairs of modulation symbols, modulating the one or more pilot carriers of the first version of the OFDM symbols, generating a second pair of modulation symbols for each of the pairs of data symbols, the second pair 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 symbols, forming 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, modulating the one or more pilot symbol sub-carriers of the second version of the OFDM symbols, and 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 modulating the one or more pilot symbol sub-carriers of the first version of the OFDM symbols and the modulating the one or more pilot symbol sub-carriers of the second version of the OFDM symbols includes modulating 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 pairs of modulation symbols forming the Alamouti cell, are separated within the first and second versions of the OFDM symbols by at least one other data bearing sub-carrier or one or more scattered or continuous pilot symbol sub-carriers. - View Dependent Claims (15)
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16. A system for communicating 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 system comprising an apparatus for transmitting and an apparatus for receiving,
the apparatus for transmitting 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, and the apparatus for receiving comprises a receiver for receiving a first version of the OFDM symbols transmitted from a first antenna, and a second version of the OFDM symbols transmitted from a second antenna, a demodulator operable to form an estimate of a first pair of modulation symbols for each of the pairs of data symbols from the first version of the OFDM symbols, using the one or more pilot carriers, the first pair of modulation symbols forming first and second modulation symbols of an Alamouti cell, to form an estimate of a second pair of modulation symbols for each of the pairs of data symbols from the second version of the OFDM symbol, using the one or more pilot carriers, the second pair of modulation symbols forming third and fourth modulation symbols of the Alamouti cell corresponding to the pair of data symbols in the first version of the OFDM symbols, a data detector operable to generate an estimate of each of the pairs of the data symbols from the first, second, third and fourth modulation symbols corresponding to each of the Alamouti cells recovered from the first and second versions of the OFDM symbols, wherein for at least one of the pairs of data symbols carried by the first and second versions of the OFDM symbols, the sub-carriers carrying the modulation symbols of the first and second modulation symbols and the third and the forth modulation symbols forming the Alamouti cells are separate within the first and second versions of the OFDM symbol respectively by at least one other data bearing sub-carrier or one or more of the pilot carriers, and the data detector is operable to detect the pair of data symbols carried by the sub-carriers which are separated by the at least one other data bearing sub-carrier or pilot carrier using a different estimate of a coefficient of the channel frequency response corresponding to the position of each of the sub-carriers within each of the first and second versions of the OFDM symbol.
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Specification