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Method for detecting Almouti code in an MIMO (multi-input multi-output)-OFDM (orthogonal frequency division multiplexing) system

A MIMO-OFDM, detection method technology, applied in transmission systems, multi-frequency code systems, error prevention/detection through diversity reception, etc., can solve detection performance degradation, receiving antenna gain imbalance, receiving antenna noise imbalance, etc. question

Inactive Publication Date: 2012-12-12
SHANGHAI RES CENT FOR WIRELESS COMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in practical systems such as LTE, each receiving antenna uses a different RF link. If the specifications of the RF modules of different RF links are different, the noise generated by the RF link will be different; and different antennas are affected by The degree of external interference may also be different, which causes the noise imbalance between the receiving antennas
In addition, each receiving antenna in the actual system uses an independent AGC module to control the signal amplitude input to the AGC module. Since the wireless channel between the receiving antenna and the transmitting antenna is independently and randomly fading, the gain between the receiving antennas is also unbalanced
In the previous literature, when studying Alamouti codes, it was assumed that the noise and gain between the receiving antennas were equal. This assumption greatly simplifies the problem and produced many meaningful results. However, if the noise and gain are not If the balance problem is not handled well, it will seriously degrade the detection performance

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  • Method for detecting Almouti code in an MIMO (multi-input multi-output)-OFDM (orthogonal frequency division multiplexing) system
  • Method for detecting Almouti code in an MIMO (multi-input multi-output)-OFDM (orthogonal frequency division multiplexing) system
  • Method for detecting Almouti code in an MIMO (multi-input multi-output)-OFDM (orthogonal frequency division multiplexing) system

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Embodiment 1

[0031] This embodiment provides a method for detecting Alamouti codes in a MIMO-OFDM system. The problem to be solved by this method is how to design the Alamouti codes in a MIMO-OFDM system when considering the imbalance of noise and gain between receiving antennas. The detection method makes the detection performance have obvious gains compared with the traditional Alamouti code detection method that does not consider this problem.

[0032] Based on this problem, the main content of the Alamouti code detection method in the MIMO-OFDM system described in this embodiment is:

[0033] Both the transmitting end and the receiving end are equipped with two antennas, and each receiving antenna uses an independent radio frequency link. At the same time, in order not to lose generality, this embodiment does not specify that the Alamouti code is coded in the time domain or the frequency domain, but that Encode on two intervals. The modulated complex signal (s 0 ,s 1 ) is transmitte...

Embodiment 2

[0045] The scenario provided in this embodiment is: both the receiving end and the transmitting end are equipped with two antennas, and Alamouti coding is used on OFDM subcarriers.

[0046] The detection method of the MIMO-OFDM system Alamouti code described in the present embodiment is: suppose two adjacent subcarrier frequencies are respectively f 0 and f 1 , the corresponding frequency response is H 0 and H 1 . Subcarrier f 0 and f 1 The received signals on are:

[0047] r 0 ( 0 ) r 0 ( 1 ) = H 0 ...

Embodiment 3

[0055] The problem to be solved by the present invention is to design an effective Alamouti code detection method under the condition of unbalanced noise and gain among diversity paths, so as to improve the detection performance.

[0056] The detection method of the Alamouti code in the MIMO-OFDM system proposed in this embodiment is to weight the received signal so that the noise energy on the final receiving antenna is equal to obtain better detection performance than the original detection method of the Alamouti code. The main idea of ​​the Alamouti code detection method in the MIMO-OFDM system proposed by the present invention is to adjust the received signal amplitude during detection, so that the noise energy in the adjusted signals of each receiving antenna is equal.

[0057] This embodiment is the promotion of Embodiment 1. The difference between it and Embodiment 1 is that the transmitting end is equipped with multiple antennas of 2, and the receiving end is equipped w...

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Abstract

The invention discloses a method for detecting an Almouti code in an MIMO (multi-input multi-output)-OFDM (orthogonal frequency division multiplexing) system. A sending end is provided with antennas in the number of a multiple of two, a receiving end is provided with Nr antenna, and receiving signals in two intervals are shown as follows, wherein G0=0, and Gj refers to the radio frequency link gain of the receiving antenna j (j=0, 1, ..., Nr-1) relative to the receiving antenna 0. Noise variances of the receiving antenna i and detection signals are shown as follows, wherein the weighting factor wi satisfies the equation of wi=(Giai)-1, and i=0, 1. The method for detecting the Almouti code in the MIMO-OFDM system gives consideration to serious influences of noises and unbalanced gain among the receiving antennas on signal detection, and obtains performance gain higher than that of a traditional Almouti code detection method, and detection performance is improved.

Description

technical field [0001] The invention belongs to the technical field of communication, and relates to a method for detecting Alamouti codes in an MIMO-OFDM system in consideration of noise and gain imbalance between receiving antennas. Background technique [0002] With the demand for high data rate communication and the scarcity of spectrum resources, multiple input multiple output (Multiple Inputs Multiple Outputs, MIMO) technology has been proposed in the field of research and engineering, which effectively improves the capacity of the communication system and the reliability of data transmission. . In the MIMO system, both the transmitting end and the receiving end are equipped with multiple antennas. Space Time Coding (Space Time Coding) is a main technology that can achieve space diversity and coding gain. The most important and practical space-time coding technique found in the research is the Alamouti code, because it is simple to encode and decode, and can achieve ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B17/00H04L1/06H04L27/26
Inventor 朱磊熊勇杨秀梅贾国庆雷舒培易正琨
Owner SHANGHAI RES CENT FOR WIRELESS COMM