Differential space-time coding and orthogonal frequency division multiplexing encoding method for LEO system based on double sampling

A technology of orthogonal frequency division and encoding method, which is applied in the field of differential space-time orthogonal frequency division multiplexing based on double sampling, and can solve problems such as large complexity, inaccurate sampling value, and intersymbol interference

Active Publication Date: 2017-11-07
HANGZHOU DIANZI UNIV
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Problems solved by technology

In the traditional method, the receiving end samples at the symbol rate after receiving the coded signal. However, when the time delay difference is an integer multiple of the non-symbol period, the sampling point will be inaccurate due to the deviation from the peak position of the symbol, and the sampling value will also be superimposed. Into the sampling value of the side lobe, causing inter-symbol interference
In addition, when decoding, the receiving end needs to obtain the instantaneous channel state information (CSI) through channel estimation, so as to realize the coherent detection of the signal, which has great complexity

Method used

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  • Differential space-time coding and orthogonal frequency division multiplexing encoding method for LEO system based on double sampling
  • Differential space-time coding and orthogonal frequency division multiplexing encoding method for LEO system based on double sampling
  • Differential space-time coding and orthogonal frequency division multiplexing encoding method for LEO system based on double sampling

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Embodiment Construction

[0083] Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and attached tables.

[0084] figure 1 It is the system model diagram in the case of double LEO satellite relay. The system in the figure consists of a transmitter S, two relay satellites R 1 , R 2 and a receiving end D, the nodes in the system are all single-antenna structures, and the transmission mode is half-duplex. S first encodes the signal and broadcasts it to R 1 , R 2 , each relay performs space-time coding processing on the received signal and forwards the signal to D using the Amplify and Forward protocol (AF). There is no direct signal at the two ends of the ground during the whole process.

[0085] figure 2 A diagram of the improved double-sampling receiver model. The sampler has two sampling points to sample the signal in one symbol period, and the receiving end is at the symbol rate 0,±T s ,±2T s ,…while timing sampling at ±T s / ...

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Abstract

The invention discloses a differential space-time coding and orthogonal frequency division multiplexing encoding method for an LEO system based on double sampling. The method comprises the following steps of firstly, constructing an asynchronous double relay network model under an LEO satellite channel; secondly, carrying out differential DTSC-OFDM encoding; thirdly, constructing a double sampling receiver; and lastly, carrying out differential decoding through a receiving end. The double sampling method based on a differential DSTC-OFDM encoding condition can overcome intersymbol interference caused by frequency selective fading, and meanwhile, complicated channel estimation is removed from transmitting and receiving ends; the transmitting end adopts a double sampling way to improve an average received signal to noise ratio of the receiving end, so that the system performance reduction caused by delay inequality of decimal parts is avoided. Compared with the prior art, when the system has the delay inequality of the decimal parts, the bit error rate performance can be well improved.

Description

technical field [0001] The invention belongs to the technical field of information and communication engineering, and relates to space-time coding and detection technology in LEO satellite cooperative communication, in particular to a differential space-time orthogonal frequency division multiplexing method based on double sampling. Background technique [0002] In recent years, with the gradual implementation of the air-ground integration system, the demand for using LEO artificial satellites to provide communications for radio communication stations in water, land, and air space has increased dramatically. Using distributed space-time coding (DSTC) to use multiple LEO satellites as relays to form a virtual multiple-input multiple-output (MIMO) system that resists channel fading has gradually become one of the hot topics in satellite communication technology research in recent years. However, due to the different positions of the satellites in the relay system, there is a d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B7/185H04L1/06H04L12/24H04L27/26
CPCH04B7/1851H04B7/18526H04L1/0618H04L27/2614H04L27/2697H04L41/145
Inventor 章坚武屠贺嘉琦
Owner HANGZHOU DIANZI UNIV
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