Method and device for detecting symbols of OFDMA multiaerial system

A detection method and symbol technology, applied in diversity/multi-antenna systems, space transmit diversity and other directions, can solve problems such as difficulty in interference suppression, and achieve the effects of interference suppression and time-frequency diversity

Inactive Publication Date: 2012-12-05
BEIJING XINWEI TELECOM TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, suppressing interference while combating multipath fading is a difficult problem

Method used

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  • Method and device for detecting symbols of OFDMA multiaerial system
  • Method and device for detecting symbols of OFDMA multiaerial system
  • Method and device for detecting symbols of OFDMA multiaerial system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Embodiment 1: as figure 1 As shown, the signal is transmitted on a set of time-frequency grids, and the set of time-frequency grids is divided into 4 groups, each group is a subset containing adjacent time-frequency grids, and a null symbol is assigned to each group. The allocation method can be as figure 1 As shown in (a), the empty symbols allocated by each group are different; the allocation method can also be as follows figure 1 As shown in (b), group 1 and group 2 share a null symbol, and group 3 and group 4 share a null symbol.

[0037] For receivers with multiple antennas, such as figure 2 As shown, the message signal vector x of the received i-th group s i (k, t), pilot vector x p i (k, t) and an empty signed vector x n i (k, t) is as follows:

[0038] x s i ( k , t ) = h s i ...

Embodiment 2

[0052] Embodiment 2: The information symbols transmitted in this embodiment are CS-OFDMA signals. The L message symbols s to be transmitted are multiplied to the left by s by the code spreading matrix w to generate a CS-OFDMA signal.

[0053] x=w·s

[0054] X=[x 1 , x 2 ,...,x N ] T

[0055] image 3 is a block diagram of the transmission process of the transmitter of this embodiment, the CS-OFDMA signal {x n} After subcarrier mapping, IFFT transformation and D / A conversion, it is transmitted through the radio frequency antenna.

[0056] Figure 4 is a block diagram of the reception processing of the receiver of this embodiment. First, the beamforming weight is calculated according to the spatial characteristics of each group and the user interference matrix; then, according to the beamforming weight of each group, each group is spatially merged; a spatially merged message signal {y i} form a set, and extract a space-combined pilot symbol from each group {y p i} fo...

Embodiment 3

[0064] Embodiment 3: as Figure 5 As shown, after detecting the initial signal symbols s, they can be modulated again to generate Will The beamforming weights can be further refined as a training signal. In this example, The remodulation of is as follows: x ~ = W · s ~

[0065] Then construct the user data matrix R for each group y i and user correlation vector R y i , calculate the improved beamforming weights of the i-th group according to the minimum mean square error criterion, as follows:

[0066] R y i = Σ n = 1 L x s i ( k n , t n )...

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Abstract

The invention proposes method for detecting symbols of an OFDMA multiaerial system with multiple information source signals transmitted on the same wireless resource. The method comprises the following steps: a. grouping received information signal vectors and pilot frequency symbolic vectors, the information signal vectors and pilot frequency symbolic vectors in each group are adjacent on subcarriers and symbol periods and are allocated with at least one empty symbol vector; b. estimating user interference matrixes according to empty symbol vectors in each group; c. estimating space characteristics according to the pilot frequency symbol vectors and / or information signal vectors in each group; d. generating a beam forming weight according to the space characteristics and user interference matrixes in each group; e. space combining the information signal vectors and the pilot frequency symbol vectors in each group; f. extracting at least one space-combined information signal and pilotfrequency symbol from each group and detecting the information symbols. The invention also proposes a device for detecting symbols and can suppress interference in interference and multi-path fading channels and realize time-frequency diversity.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to a symbol detection method and device for an OFDMA multi-antenna system. Background technique [0002] Interference and multipath fading are two important factors affecting system performance. In OFDMA wireless systems, the multipath problem is solved by introducing a cyclic prefix to each symbol. To combat fading, time-frequency diversity is achieved by transmitting signals on different subcarriers and time slots. After the symbols are channel coded, when some signals encounter fading, the remaining high-quality symbols can still be used to recover useful signals. However, it is a difficult problem to suppress interference while fighting against multipath fading. What makes this problem even more serious is that the available signals that can be used to learn the signal and interference characteristics are limited, so it is necessary to propose an effective scheme that ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B7/06H04B7/08
Inventor 李航徐广涵
Owner BEIJING XINWEI TELECOM TECH
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