run_sender.c

完整的OFDM系统,含Matlab仿真代码和DSP源代码下载.平台Tms320C6000.含项目说明文档.绝对高质量的源代码.

//run_sender.c
//
// Project Red 2002: High Performance OFDM Modem 
// Against Channel Imperfections
// Auther: Linus Falk

#include "ofdm.h"
#include "get_data.h"
#include "mod.h"
#include "compcomp.h"
#include "cyclpref.h"

float frame1[FRAME_LENGTH];
float frame2[FRAME_LENGTH];

#pragma DATA_SECTION(BitLoadBuffer1, ".edata");
volatile bitload_struct BitLoadBuffer1;
#pragma DATA_SECTION(BitLoadBuffer2, ".edata");
volatile bitload_struct BitLoadBuffer2;
volatile bitload_struct *CurrentBitLoadBuffer;
volatile bitload_struct *NextBitLoadBuffer;

unsigned int frame_number = 0;
float *current_frame;

void build_frame(void);
void print_frame(float frame[FRAME_LENGTH]);

void run_sender(void){
	
	wait_for_host();
		
	//build the 2 initial frames
	current_frame = frame1;
	memset(current_frame, 0,FRAME_LENGTH*sizeof(float));
	build_frame();
	current_frame = frame2;
	memset(current_frame, 0,FRAME_LENGTH*sizeof(float));
	build_frame();
		
	/* Start DMA Ch2 Transfer */
    DMA_AUTO_START(DMA_CH2);
    //DMA_START(DMA_CH2);
        	    	
    //run forever	
	while(TRUE){
	}
}

void build_frame(void){
	unsigned int i,t;
	unsigned char data;
	const unsigned char training[] = {1,0,3,1,2,2,3,2,0,1,1,1,1,3,1,3};
	unsigned char modulation;
	
	//increase frame number, 1..1024
	frame_number = frame_number%1024;
	frame_number++;
	//update bitloading
	/*if(NextBitLoadBuffer->use_from_frame == frame_number){	//time to change bitload buffer
		if(CurrentBitLoadBuffer == &BitLoadBuffer1){
			NextBitLoadBuffer = CurrentBitLoadBuffer;
			CurrentBitLoadBuffer = &BitLoadBuffer2;
			//pci_message_send(FILL_BITLOADBUFFER1_MM);
									
		}else{
			NextBitLoadBuffer = CurrentBitLoadBuffer;
			CurrentBitLoadBuffer = &BitLoadBuffer1;
			//send mail to host to fill buffer2
			//pci_message_send(FILL_BITLOADBUFFER2_MM);
		}
	}*/
	//build frame
	for(i=0,t=0; i< NR_OF_CHANNELS; i++){
		if((i-3)%8 == 0){ 	
			//training data always 2bit
			data = training[t++];
			
			//modulate, always use 4QAM on training bits
			mod(data, (char)2, current_frame+(i*2+2+PREFIX_LENGTH));	//+2 Depending on the fact that the 2 first will be set to 0;
		}else if(i<3 || i>=124){ //don't send on lowest and highest channels
			
			current_frame[i*2 +2 +PREFIX_LENGTH] = 0;
			current_frame[i*2 +3 +PREFIX_LENGTH] = 0;
		}else{
			modulation = CurrentBitLoadBuffer->channel_modulation[i];				
			get_data(modulation,&data);	//get data from Host
			//modulate
			mod(data, (char)modulation, current_frame+(i*2+2+PREFIX_LENGTH));	//+2 Depending on the fact that the 2 first will be set to 0;
		}
	}
	
	//complex complete
	compcomp(current_frame+PREFIX_LENGTH);

	//do ifft
	ifft(current_frame+PREFIX_LENGTH);
	
	//Remove Im part, and add cyclic prefix
	addCyclPref(current_frame);
	
	//puts("block ready");
}


interrupt void isr_build_frame(void) 	// ISR for DMA channel 2 
{
    unsigned int sec_ctrl;
    
    // Read memory-mapped register 
    sec_ctrl = REG_READ(DMA2_SECONDARY_CTRL_ADDR);

   	// Get BLOCK COND bit 
   	if (GET_BIT(&sec_ctrl, BLOCK_COND))
    	RESET_BIT(&sec_ctrl, BLOCK_COND);	// Reset/clear bit 
 
    // Write to memory-mapped register 
    REG_WRITE(DMA2_SECONDARY_CTRL_ADDR, sec_ctrl);
     
	DMA_GADDR_B = (unsigned int) current_frame;
	
    
    // Performs signal processing on current block 
    build_frame();
        
	//switch frame
	if(current_frame == frame1){
		current_frame = frame2;
	}else{
		current_frame = frame1;
	}
} 

void init_bitload(void){
	int i;
	BitLoadBuffer1.use_from_frame = 1;
	BitLoadBuffer2.use_from_frame = 512;
	for(i=0; i< 127; i++){
		BitLoadBuffer1.channel_modulation[i] = 4;
		BitLoadBuffer2.channel_modulation[i] = 4;	
		
	}
	CurrentBitLoadBuffer = &BitLoadBuffer1;
	NextBitLoadBuffer = &BitLoadBuffer2;
}