Realization method of Gray code M-QAM modulating parallel soft bit information computation

Abstract

The invention relates to a realization method of Gray code M-QAM modulating parallel soft bit information computation, belonging to the field of wireless communication technology; the method comprises the following steps: signals at a transmitting end are processed as follows: the signal at the transmitting end is coded to obtain the coded signal, and Gray code M-QAM modulation is carried out to the signal; the signal which carries out Gray code M-QAM modulation carries out power normalization, so as to obtain the modulating signal with normalized power; the modulating signal with normalized power is transmitted. The signals at a receiving end are processed as follows: channel estimation is carried out to the signal which passes through an information channel and is received by the receiving end, so as to obtain channel impulse response; parallel soft bit information computation is carried out to the received signal according to the channel impulse response, so as to realize M-QAM soft modulation and obtain the soft modulation signal; a demodulation symbol is output and is transmitted to a coding module; in the realization method, a system modeling tool Ayatem Generator for DSP in XILIN company, which is applied to XILINX Virtex-4 FPGA is adopted.

Description

technical field [0001] The invention relates to a method for realizing parallel soft bit information calculation of Gray coded M-QAM modulation, and belongs to the technical field of wireless communication. Background technique [0002] Realizing high-speed and large-capacity wireless communication on limited spectrum resources is a research hotspot in the field of wireless communication today. In order to achieve the above objectives, technologies with extremely high spectral efficiency are required. Multi-ary Quadrature Amplitude Modulation (M-QAM) based on Gray coding is a high-order modulation method combining amplitude and phase. It has high spectrum efficiency and is widely used in modern wireless communication systems. The gray coded constellation map mapping method makes only one bit different between every two adjacent symbols. When the signal-to-noise ratio is large, most errors are caused by adjacent points. At this time, the error A symbol is basically a bit wr...

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Problems solved by technology

[0003] In the traditional M-QAM modulation, when demodulating at the receiving end, the signal needs to be equalized, and the method of searching the minimum Euclidean distance of constellation points is used, which requires a large amount of calculation and is complicated to implement in the hardware system.

The existing wireless modulation and demodulation method in which the transmitting end adopts Gray coded M-QAM modulation and the receiving end adopts soft-decision demodulation involves division and equalization, and the calculation is complicated, which is not conducive to hardware implementation.

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