Wireless communication system as well as base station and symbol sending method thereof

A wireless communication system and symbol technology, applied in the field of communication, can solve the problems of limited space diversity gain of multiple cells, and achieve the effects of enhancing frequency diversity gain, improving throughput, and reducing feedback

Inactive Publication Date: 2011-05-25
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, although the above scheme does not require coordinated signaling between multiple cells, the spatial diversity gain of multiple cells is very limited

Method used

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  • Wireless communication system as well as base station and symbol sending method thereof
  • Wireless communication system as well as base station and symbol sending method thereof
  • Wireless communication system as well as base station and symbol sending method thereof

Examples

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Effect test

no. 1 example

[0031] Cyclic delay diversity technology is a simple single-cell transmit diversity technology that is not affected by the number of transmit antennas. figure 2 It shows the OFDM modulation process on a single antenna when cyclic delay diversity technology is adopted. Such as figure 2 As shown, after the input data symbol undergoes S-point IFFT in the S-point inverse fast Fourier transform (IFFT) unit 210, it is converted into a serial symbol in the parallel / serial converter 212, and subsequently, the cyclic delay unit 214 performs serial The row symbols are cyclically shifted, and finally, the cyclic prefix generator 216 adds a cyclic prefix to the cyclically shifted data symbols to form OFDM symbols. By applying cyclic delay diversity technology among multiple antennas in a single cell, the space diversity gain of multiple antennas can be transformed into an equivalent enhanced frequency diversity gain.

[0032] In order to obtain the enhanced space diversity gain of mul...

no. 2 example

[0041] As mentioned above, in the data transmission method of the first embodiment of the present invention, the cyclic delay diversity technique and the space-frequency block coding scheme are adopted. An enhanced frequency diversity gain can be obtained by applying a cyclic delay diversity technique between corresponding transmit antennas of multiple cell base stations.

[0042] However, we know that the application of cyclic delay diversity technology between multiple cells will equivalent MISO channel to SIMO channel, and this equivalent channel has more obvious frequency selectivity, so that between adjacent subcarriers The original high correlation does not exist. A simple space-frequency block code detector implies the requirement that the channel gains on the two subcarriers used to transmit a pair of data symbols coded according to the space-frequency block code be nearly the same, that is, the channel gains on the two subcarriers The channel gain of needs to be high...

no. 3 example

[0054] In the previous embodiments, the cyclic delay values ​​in the time domain and frequency domain implementations of the cyclic delay operation step are respectively passed by and Δ i =(i-1)N / M to determine. In practice, the cyclic delay value may have some other variations. For example, the cyclic delay value can have an initial delay amount Δ 0 , that is to say, the cyclic delay value can be transformed into and

[0055] Δ i =(i-1)N / M+Δ 0 . On the other hand, the initial delay amount Δ 0 Can be time-varying in different OFDM frames, whereby the cyclic delay value can be modified as and

[0056] Δ i (t)=(i-1)N / M+Δ t , which can increase the time diversity gain.

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Abstract

The invention provides a wireless communication system and a method for sending symbols to a user terminal by base stations of a plurality of cells according to a cooperation multipoint transmission way. The method comprises the steps of: loading the symbols on an orthogonal frequency division multiplexing subcarrier according to a coding way of a space-frequency block code in the base station of each cell, wherein continuous symbols are loaded on the subcarrier with weak relativity and symbol pairs encoded according to the space-frequency block code are loaded on two subcarriers with strong relativity; carrying out cycle delay operation on the symbols loaded on the orthogonal frequency division multiplexing subcarrier among the corresponding transmitting antennas of the base station of each cell; and sending the symbols subjected to the cycle delay operation to the user terminal according to the cooperation multipoint transmission way. The method is not affected by the amount of the cells, is in step with the technology in the LTE (Long Term Evolution) standard Re 1-8 versions and can provide enhanced frequency diversity gains of the base stations of a plurality of cells.

Description

technical field [0001] The present invention generally relates to the field of communication, and in particular to a wireless communication system, a base station in the system, and a method for sending symbols to user terminals by base stations of multiple cells in the wireless communication system using coordinated multipoint transmission. Background technique [0002] At present, for modern multi-antenna wireless communication systems based on OFDM (Orthogonal Frequency Division Multiplexing), such as LTE-A (Long Term Evolution-Advanced) under design, downlink Coordinated Multi-Point transmission (Coordinated Multi-Point transmission / Reception, CoMP) has shown its technical superiority in improving the throughput of cell edge users and the average throughput of the entire cell, so it has attracted much attention. [0003] Most of the previous research work focused on closed-loop downlink CoMP transmission technology. However, closed-loop communication systems have the f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/06H04L27/26H04B7/06H04B7/12
CPCH04L1/0606H04L5/0007H04B7/0667H04J11/0053H04B7/024
Inventor 徐静徐明张治星野正幸今村大地
Owner PANASONIC CORP
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