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Adaptive modulation method for index modulation OFDM

An adaptive modulation and index modulation technology, applied in the field of index modulation OFDM, adaptive modulation technology, and adaptive modulation, can solve the problems of orthogonal inter-carrier interference, peak-to-average ratio, OFDM is not suitable for high-speed scenarios, etc. The effect of complexity, reducing search space, and improving BER performance

Active Publication Date: 2017-11-03
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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Problems solved by technology

However, in high-speed scenarios, the orthogonality between sub-channels will be damaged by Doppler frequency shift, causing inter-carrier interference, and the superposition of OFDM multiple sub-channel signals will also lead to a higher peak-to-average ratio. These shortcomings are OFDM Not suitable for high-speed scenes

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  • Adaptive modulation method for index modulation OFDM
  • Adaptive modulation method for index modulation OFDM
  • Adaptive modulation method for index modulation OFDM

Examples

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Embodiment Construction

[0039] Below in conjunction with accompanying drawing and embodiment, describe technical solution of the present invention in detail:

[0040] In this example, the EVA channel model is adopted, the vehicle speed is 60km / h, the carrier spacing is 15kHz, the ideal channel is estimated, and the total number of system carriers is 1024. The three alternative combinations used in the simulation to achieve 1.5bps / Hz are: The energy distribution vector is E=[1.75,1,0.25]. In this example, multi-block joint adaptive modulation is adopted, and the specific steps are as follows:

[0041] Step 1: Divide 1024 subcarriers into 512 subcarrier blocks, each subcarrier block consists of 2 subcarriers, 1 subcarrier is activated and 1 is silent. and combine 2 subcarrier blocks into a subcarrier group;

[0042] Step 2: For any subcarrier group, calculate the minimum Euclidean distance of all subcarrier blocks under a certain candidate modulation combination, and select the minimum value of the...

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Abstract

The invention belongs to the technical field of wireless communication, and relates to the index modulation orthogonal frequency division multiplexing (OFDM-IM) technology, interleaving technology and the adaptive technology, and specifically relates to an adaptive modulation method based on index information. The invention provides a single-carrier adaptive modulation method based on index information and an adaptive modulation method joining a plurality of subcarrier blocks. Compared with the traditional ISIM-OFDM system, the adaptive technology can enable each subcarrier group to adjust the modulation mode according to the quality of the channel condition, and the influence of the channel on the system error rate can be greatly reduced. The complexity of the single-carrier adaptive modulation method is low, the adaptive modulation method joining a plurality of subcarrier blocks can be used for avoiding the locally optimal solution of the single-carrier adaptive modulation method, thereby greatly improving the minimum Euclidean distance between symbols and improving the system performance.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, in particular to an adaptive modulation method for index modulation OFDM. The present invention relates to Orthogonal Frequency Division Multiplexing (OFDM-IM) technology based on index modulation, sub-carrier interleaving technology and adaptive modulation technology. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology plays an important role in the fourth generation mobile communication system. The orthogonality between its sub-carriers makes the fading experienced by each sub-channel relatively flat, and then reduces the inter-symbol interference by introducing a cyclic prefix, which has the characteristics of high spectrum utilization and good anti-multipath effect, and fast Fourier Transforms provide a simple, low-cost implementation of this. However, in high-speed scenarios, the orthogonality between sub-channels will be damaged by Dop...

Claims

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Application Information

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IPC IPC(8): H04L27/34
Inventor 王鹏飞欧阳昊苑杰刘晓波但黎琳肖悦
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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