CN101854327B

CN101854327B - Self-adaptive demodulating method for multi-carrier system

Info

Publication number: CN101854327B
Application number: CN2010101978634A
Authority: CN
Inventors: 袁东风; 孙健; 刘朝娜
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2010-06-11
Filing date: 2010-06-11
Publication date: 2012-08-22
Anticipated expiration: 2030-06-11
Also published as: CN101854327A

Abstract

The invention discloses a self-adaptive demodulating method for a multi-carrier system. The method comprises the following steps that: for four modulation modes of QPSK, 16QAM, 64QAM and 256QAM, control signals C 2, 4, 6 and 8 are used respectively; the control signal C is saved in a random access memorizer RAM, and a control module outputs a signal mod and a signal index under the control of an address signal output by an IFFT; 8-bit source data processed in the RAM is converted into the 16-bit data under the control of the mod and the index, wherein when the conversion is performed, a front byte is at lower 8 bits, and a rear byte is at higher 8 bits; the 16-bit data is circularly intercepted into the 8-bit data under the control of the signal index according to the principle that every 8 bits is taken as a group; the 8-bit data is mapped into I/Q two paths of data under the control of the signal mod; and the mapped data is added with auxiliary information and then is subjected to IFFT to finish the modulation. The method has the advantage of realizing different modulation modes by updating a hardware configuration structure.

Description

A kind of method that is applicable to the multicarrier system Adaptive Modulation

Technical field

The present invention relates to the method for multicarrier system Adaptive Modulation, belong to digital signal transmission technique field.

Background technology

Typical multicarrier system digital transmission system comprises transmitter and receiver.Orthogonal frequency division multiplex OFDM (Orthogonal Frequency Division Multiplexing) is a kind of typical multi-carrier modulation; The OFDM digital modulation technique is often modulated encoding digital signals; Add necessary supplementary again, like training sequence, pilot signal, synchronizing signal etc.Data behind the coding are accomplished spatial transform frequently through inverse fast fourier transform IFFT (Inverse Fast Fourier Transform).Accomplish time-frequency domain conversation, equilibrium, rectification at receiving terminal through synchronous, frequency deviation recovery, fast Fourier transform FFT (Fast Fourier Transform), recover the data consistent with transmitting terminal.

The modulation demodulation system of digital signal transmission field employing is at present fixed, and wants to realize that new modulation system must change hardware configuration, and research different modulating mode is caused difficulty.

Summary of the invention

The present invention is directed to the immutable problem of digital transmission system modulation system, provide a kind of under the situation that does not change hardware configuration through changing the method that is applicable to the multicarrier system Adaptive Modulation that parameter changes modulation system.

The method of multicarrier system Adaptive Modulation that is applicable to of the present invention is:

For QPSK, 16QAM, 64QAM, four kinds of modulation systems of 256QAM, control signal C gets 2,4,6,8 respectively; Control signal C is stored in the random access memory ram (Random Access Memory), under the control of the address signal that IFFT exports, and control module output signal mod and index; (data length is the data length in the frame among the OFDM to handled 8bit length source data in the random access memory ram; When designing new frame structure; The data of the storage among the conversion RAM) under the control of mod and index, convert the 16bit length data to; Last byte is at least-significant byte during conversion, and back one byte is at most-significant byte; The 16bit length data under the control of signal index according to one group of 8bit, the data of circulation intercepting 8bit length; The 8bit length data is mapped as the I/Q two paths of data under the control of signal mod, so just accomplished 8bit-＞16bit-＞8bit; Data after the mapping add supplementary (like training sequence, pilot signal, synchronizing signal etc.), pass through inverse fast fourier transform (IFFT) again and accomplish modulation.

For the QPSK modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 2bit data were effective, and preceding 1bit is I, and back 1bit is Q; Control signal C value is 2.

For the data interlacing of 16QAM modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 4bit data were effective, and preceding 2bit is I, and back 2bit is Q; The C value is 4.

For the 64QAM modulation system data interlacing, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 6bit data were effective, preceding 3bit is I, back 3bit is Q; The C value is 6.

For the 256QAM modulation system data interlacing, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 8bit data were effective, preceding 4bit is I, back 4bit is Q; The C value is 8.

The present invention adopts the control structure of transmitting terminal 8bit-＞16bit-＞8 (2/4/6/8) bit-＞I/Q data to carry out the transmitting terminal data interlacing; The change software parameter that passes through of success changes modulation system under the situation that does not change hardware configuration; Stress the programmability of data interlacing mapping; Through the software upgrading hardware configuration structure, realize different modulation modes, be beneficial to the continuous upgrading and the expansion of hardware module.

Description of drawings:

Fig. 1 is the block diagram of transmission system of the present invention;

Fig. 2 is the control module schematic diagram;

Fig. 3 is an interleaving block A schematic diagram;

Fig. 4 is an interleaving block B schematic diagram;

Fig. 5 is the mapping block schematic diagram;

The 16bit data became 8bit and data interlacing mapping graph when Fig. 6 was the QPSK modulation;

The 16bit data became 8bit and data interlacing mapping graph when Fig. 7 was the 16QAM modulation;

The 16bit data became 8bit and data interlacing mapping graph when Fig. 8 was the 64QAM modulation;

The 16bit data became 8bit and data interlacing mapping graph when Fig. 9 was the 256QAM modulation;

Embodiment

As shown in Figure 1, the data of input interweave, shine upon under the control of control module, and then insert pilot tone, training sequence, carry out the IFFT modulation.Interweave and the mapping block of data all is work under the control of control module.Control module is as shown in Figure 2, and interleaving block is like Fig. 3, shown in 4, and mapping block is as shown in Figure 5.The control module operation principle is: control data embeds RAM among Fig. 2 through software; RAM exports the modulation control data of being stored successively under the control of address signal; The modulation control data is respectively continuous 2 (QPSK), 4 (16QAM), 6 (64QAM), 8 (256QAM), and the modulation control data is exported modulator control signal mod under the control of enable signal, modulator control signal is connected add; Again to the data of Lian Jiahou remove 16 get surplus; Promptly get control signal index, index=(∑ mod) % (16), acting on lower module of mod and index will be introduced in detail.Address signal comes from the IFFT module of back, and this module can be controlled the length of IFFT.

As shown in Figure 3, the 8bit length data is stored among the RAM-D, dateout data_in8 under the jointly controlling of mod+index, these data control signal mod and index enable control under be combined into the 16bit length data.When mod+index=0, data_in8 data and last byte data_in8 data are formed the high 8bit and the low 8bit of data_out16 data respectively; When mod+index=8, data_in8 data and last byte data_in8 data are formed the low 8bit and the high 8bit of data_out16 data respectively.When mod+index=0 or 8, counter counter promptly adds 1, the data of for RAMD, promptly getting next address next time.

As shown in Figure 4; The 16bit length data of input is circulation intercepting 8bit length data under the selection control of control signal index, and the 8bit data are respectively [0-7] bit, [2-9] bit, [4-11] bit, [6-13] bit, [8-15] bit, [10-16:0-1] bit, [12-16:0-3] bit, [14-16:0-5] bit among the 0-16bit.The input 8bit length data as shown in Figure 5 low 2bit of intercepting is respectively carried out QPSK, low 4bit and is carried out that 16QAM, low 6bit carry out 64QAM, low 8bit carries out 256QAM, be output as Q two paths of data.Under the control of mod signal, optionally export Q two paths of data.

Shown in Fig. 6-9, in the process of 8bit-＞16bit-＞2/4/6/8bit-＞I/Q data conversion, 2/4/6/8bit is the valid data that are stored in the 8bit length data, the shared a kind of hardware configuration of promptly various interleaving modes.Promptly by position and the mapping mode thereof of control unit control valid data in 8bit length data unit.

As shown in Figure 6, during mod=2 the QPSK modulation, index=(∑ mod) % (16), index get (0,2,4,6,8,10,12,14) successively, and circulation according to this.Gained 16bit data are divided into the data of 2bit length, and these data are at the low 2bit that constitutes the 8bit length data, and the low 2bit of this 8bit length data is divided into each 1bit of I/Q two-way again and carries out the QPSK mapping.The preceding 1bit of 2bit data is I, and back 1bit is Q.Data_out8 is [0-7] bit, [2-9] bit, [4-11] bit, [6-13] bit, [8-15] bit, [10-16:0-1] bit, [12-16:0-3] bit, [14-16:0-5] bit of the intercepting data_in16 that circulates successively among Fig. 4.

As shown in Figure 7, during mod=4 the 16QAM modulation, index gets (0,4,8,12) successively, and circulation according to this.Gained 16bit data are divided into the data of 4bit length, and these data are at the low 4bit that constitutes the 8bit length data.The low 4bit of this 8bit length data is divided into each 2bit of I/Q two-way again and carries out the 16QAM mapping.The preceding 2bit of 4bit data is I, and back 2bit is Q.Data_out8 is [0-7] bit, [4-11] bit, [8-15] bit, [12-16:0-3] bit of the intercepting data_in16 that circulates successively among Fig. 4.

As shown in Figure 8, during mod=6 the 64QAM modulation, index gets (0,6,12,2,8,14,4,10) successively, and circulation according to this.Gained 16bit*3 data are divided into the data of 6bit length, and these data are at the low 6bit that constitutes the 8bit length data, and the low 6bit of this 8bit length data is divided into each 3bit of I/Q two-way again and carries out the 64QAM mapping.The preceding 3bit of 6bit data is I, and back 3bit is Q.Data_out8 is [0-7] bit, [6-13] bit, [12-16:0-3] bit of the intercepting data_in16 that circulates successively among Fig. 4; [2-9] bit, [8-15] bit, [14-16:0-5] bit; [4-11] bit, [10-16:0-1] bit.

As shown in Figure 9, during mod=8 the 256QAM modulation, index gets (0,8) successively, and circulation according to this.Gained 16bit data are divided into the data of 8bit length, and this 8bit length data is divided into each 4bit of I/Q two-way again and carries out the 256QAM mapping.The preceding 4bit of 8bit data is I, and back 4bit is Q.Data_out8 is [0-7] bit, [8-15] bit of the intercepting data_in16 that circulates successively among Fig. 4.

The present invention's successful passing through under the situation that does not change hardware configuration changes the modulation system that software parameter changes data; Can be applicable to the Adaptive Modulation of the ofdm system of any wireless transmission transmitter, also can be applicable to other needs data adaptive modulated digital communication system.

Claims

1. the method for a multicarrier system Adaptive Modulation, it is characterized in that: for QPSK, 16QAM, 64QAM, four kinds of modulation systems of 256QAM, control signal C gets 2,4,6,8 respectively; Control signal C is stored in the random access memory ram, under the control of the address signal that IFFT exports, and control module output signal mod and index; Handled 8bit length source data converts the 16bit length data in the random access memory ram under the control of mod and index, and last byte is at least-significant byte during conversion, and back one byte is at most-significant byte; The 16bit length data under the control of signal index according to one group of 8bit, the data of circulation intercepting 8bit length; The 8bit length data is mapped as the I/Q two paths of data under the control of signal mod, so just accomplished 8bit-＞16bit-＞8bit; Data after the mapping add supplementary, accomplish modulation through inverse fast fourier transform again;

The modulation control data is respectively continuous 2,4,6,8; The modulation control data is exported modulator control signal mod under the control of enable signal, modulator control signal connected add, again to the data of Lian Jiahou except that 16 get surplus; Promptly get control signal index, index=(∑ mod) % (16);

The 8bit length data is stored among the RAM-D; Dateout data_in8 under the jointly controlling of mod+index; These data control signal mod and index enable control under be combined into the 16bit length data; When mod+index=0, data_in8 data and last byte data_in8 data are formed the high 8bit and the low 8bit of data_out16 data respectively; When mod+index=8; Data_in8 data and last byte data_in8 data are formed the low 8bit and the high 8bit of data_out16 data respectively; When mod+index=0 or 8, counter counter promptly adds 1, the data of for RAMD, promptly getting next address next time;

For the QPSK modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 2bit data were effective, and preceding 1bit is I, and back 1bit is Q; The C value is 2;

For the 16QAM modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 4bit data were effective, and preceding 2bit is I, and back 2bit is Q; The C value is 4;

For the 64QAM modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 6bit data were effective, and preceding 3bit is I, and back 3bit is Q; The C value is 6;

For the 256QAM modulation system, wherein in the data interlacing of 8bit-＞16bit-＞8bit, when gained 16bit data were divided into the 8bit length data, its low 8bit data were effective, and preceding 4bit is I, and back 4bit is Q; The C value is 8.