Emission diversity method for time-domain orthogonal frequency dividing duplexing system

An orthogonal frequency division and time domain synchronization technology, applied in the field of digital information transmission, can solve the problems of frequency selective fading channel inapplicability, channel assumption error, etc.

Inactive Publication Date: 2007-01-10
TSINGHUA UNIV
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Problems solved by technology

Although SFC-OFDM can be applied to fast fading channels, it is not applicable to frequency selective fading channels due to the error caused by channel assumptions
Howe

Method used

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  • Emission diversity method for time-domain orthogonal frequency dividing duplexing system
  • Emission diversity method for time-domain orthogonal frequency dividing duplexing system
  • Emission diversity method for time-domain orthogonal frequency dividing duplexing system

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Embodiment Construction

[0132] See Figure 4 . The frequency-domain input sequence in this system is a complex signal after modulation mapping (constellation map mapping), which can be a non-coded signal or a coded signal. The input sequence in the frequency domain is first divided into odd subsequences and even subsequences according to subcarrier numbers, and their lengths are both N / 2. Then, a total of four N / 2 long subsequences of two consecutive frames of input data are respectively subjected to N / 2 point inverse discrete Fourier transform, and the result x 1 to (n, l), x 1 te (n, l), x 1 to (n, l+1) and x 1 te (n, l+1) is stored in the cache and stored in the cache. Using the operational properties of the inverse discrete Fourier transform, simple complex multiplication and addition calculations are performed on the data in the cache in the following four cases to obtain the time domain signals of the four transmission links:

[0133] 1) For antenna Tx1:

[0134] ...

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Abstract

The invention includes steps: (1) dividing input sequence in frequency domain into odd and even sub sequences in length N/2 according to sequence number of sub carrier wave; (2) carrying out inversed discrete Fourier transform for continuous two frames of the said sub sequence, storing result to buffer; (3) calculating buffered data so as to obtain four signals in time domain in transmitting chain; (4) inserting different PN sequences as frame head into TDS-OFDM guard gaps of four transmitting chain respectively, building up integrated signal frame of each transmitting chain from the frame head and frame body obtained from previous step; (5) after forming filtering, D/A conversion, and process at front end, signal frames are transmitted out through four antennae at prearranged channel bandwidth. Advantages are: simple, quick, accuracy, holding transmission efficiency, more suitable to channel of dual selections of time and frequency, supporting 'soft failure'etc.

Description

technical field [0001] The invention belongs to the technical field of digital information transmission, and more specifically relates to a time-frequency signal based on a space-time block code (Space-Time Block Code) in a time-domain synchronous orthogonal frequency division multiplexing (TimeDomain Synchronous OFDM, TDS-OFDM) system. domain joint transmit diversity method. Background technique [0002] In a complex wireless environment, surrounding objects (such as houses, buildings or trees, etc.) will reflect radio waves. These obstacles produce reflected waves with different amplitude attenuation and phase delay. If a modulated signal is transmitted, multiple reflections of the transmitted signal arrive at the receiving antenna from different directions with different propagation delays. After these reflected signals are received by receiver antennas located at various places, they will strengthen or weaken the received signal according to the difference of their ran...

Claims

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Application Information

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IPC IPC(8): H04L1/06H04L27/26
Inventor 杨知行王劲涛潘长勇宋健王军
Owner TSINGHUA UNIV
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