Transmit diversity from orthogonal design for fbmc/oqam

Patent metadata

Field	Value
Publication number	US-2018367353-A1
Application number	US-201615562989-A
Country	US
Kind code	A1
Filing date	Apr 1, 2016
Priority date	Apr 1, 2015
Publication date	Dec 20, 2018
Grant date	—

Abstract

How to apply an Alamouti like space-time coding (or transmit diversity) to a Filter Bank Multicarrier (FBMC) transmission using Offset QAM (OQAM). In FBMC, due to the orthogonality in the real domain only, an intrinsic interference results thereof for the imaginary component. Simply adapting the Alamouti scheme to FBMC OQAM is not obvious since the intrinsic interference terms are not equivalent at each antenna since it depends on the surrounding symbols. The application proposes to choose contiguous precoding symbols such that a virtual PAM Alamouti scheme is achieved. Code rates of 1/2 or 2/3 are achieved depending on the number of precoding symbols needed per antenna.

First claim

1 . A method for transmitting a multicarrier signal using a transmit diversity technique with a plurality of transmit antennas (Tx1, Tx2),
wherein said signal is of the offset quadrature amplitude modulation, OQAM, type comprising symbols in the time-frequency space, wherein the symbols include a data containing symbol (a) and a precoding symbol (x), and wherein the precoding symbol (x) is selected such that intrinsic interference (I) at the data containing symbol (a), when received by a receiver, is forced to a value which ensures an applied orthogonal space-time or space-frequency code.

2 . The method for transmitting of claim 1 , wherein said symbols are formed by modulating a real-valued symbol and the intrinsic interference corresponds to the imaginary part of the demodulated signal at said receiver, or
said symbols are formed by modulating an imaginary valued symbol and the intrinsic interference corresponds to the real-valued part of the demodulated signal at said receiver.

3 . The method for transmitting of claim 1 , wherein the selecting of the precoding symbol is performed by forcing the intrinsic interference, when received by the receiver, to be zero.

4 . The method for transmitting according to claim 1 , wherein one precoding symbol is used for each transmitted symbol to cancel out the composite intrinsic interference through transmission of the same PAM symbol by the two antennas, when received by a receiver, to be zero.

5 . The method for transmitting of claim 1 , wherein there are transmitted real-valued PAM symbols a 1 and a 2 are transmitted using the two resources (m 0 ,n 0 ) and (m 0 +1,n 0 ) from the transmit antenna Tx1, wherein from transmit antenna Tx2, these PAM symbols a 1 and a 2 are transmitted with and respectively without taking its minus by using the same two resources but now the used resources for a 1 and a 2 are exchanged so that the receive signals for the subcarriers m 0 and m 0 +1 read as

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Assignees

• Ntt Docomo Inc

Inventors

• Weitkemper Petra
• Kusume Katsutoshi
• Bazzi Jamal
• Iwamura Mikio

Classifications

• H04L27/264 Primary

  Pulse-shaped multi-carrier, i.e. not using rectangular window · CPC title

• H04L27/2698

  double density OFDM/OQAM system, e.g. OFDM/OQAM-IOTA system · CPC title

• H04L1/0668 Primary

  Orthogonal systems, e.g. using Alamouti codes · CPC title

• H04L27/26416

  Filtering per subcarrier, e.g. filterbank multicarrier [FBMC] · CPC title