Constellation diagram design method for index modulation ofdm system

A technology of index modulation and design method, applied in modulated carrier systems, wavelet modulated carrier systems, transmission systems, etc., 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 large Euclidean distance, increased transmission accuracy, and improved BER performance

CN107332799BActive Publication Date: 2019-07-12UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2019-07-12

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Abstract

The invention belongs to the technical field of wireless communication, and relates to an index modulation orthogonal frequency division multiplexing (OFDM-IM) technology, a constellation diagram design technology and an adaptive technology, in particular to a constellation diagram design and adaptive modulation method for the index modulation OFDM system. The constellation diagram design method comprises the following steps: firstly, giving an alternative modulation combination, and designing a proper constellation diagram; and adaptively selecting a modulation way according to the designed constellation diagram, so that each subcarrier wave block selects an optical modulation way from the alternative modulation combination. Compared with a conventional ISIM-OFDM (Interleaved Subcarrier Index Modulation-Orthogonal Frequency Division Multiplexing) system, the constellation diagram design method has the advantages that an adaptive modulation technology is adopted at a transmitting end, so that the situation of relatively high bit error rate of a single modulation way under a poor channel condition is avoided. The constellation diagram is designed, so that the Euclidean distance between modulation symbols can be increased, and the transmission accuracy is increased.
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Description

technical field

[0001] The invention belongs to the technical field of wireless communication, and specifically relates to a constellation diagram design method for an index modulation OFDM system, and proposes an adaptive modulation method according to the designed constellation diagram. The invention relates to an index modulation-based Orthogonal Frequency Division Multiplexing (OFDM-IM) technology, an adaptive modulation technology, a constellation diagram design technology and the like. Background technique

[0002] Orthogonal Frequency Division Multiplexing (OFDM) [8] technology has become one of the core technologies of the 4G 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 transform It provide...

Examples

example 1

[0036] In this example, the EVA channel model is used, the vehicle speed is 60km / h, the carrier spacing is 15kHz, the ideal channel is estimated, the total number of system carriers is 1024, and the interleaving is divided into blocks. The 3 alternative combinations used to achieve 1.5bps / Hz are: The energy allocation vector is E=[1.75,1,0.25]. The corresponding constellation diagram is designed as figure 2 . On the detection side, this example takes the following steps:

[0037] Step 1: Divide 1024 subcarriers into 256 subcarrier blocks, each subcarrier block consists of 4 subcarriers, 2 subcarriers are activated, and 2 are silent;

[0038] Step 2: For any subcarrier block, calculate the minimum Euclidean distance under a certain candidate modulation combination;

[0039] Step 3: traverse all the candidate modulation combinations, select the maximum value of the minimum Euclidean distance \ corresponding to each candidate modulation combination, and its corresponding ...