rake.h

这是一个c＋＋编写的WCDMA链路采用RAKE接收的方针源代码

/*
 |
 | Copyright disclaimer:
 |   This software was developed at the National Institute of Standards
 |   and Technology by employees of the Federal Government in the course
 |   of their official duties. Pursuant to title 17 Section 105 of the
 |   United States Code this software is not subject to copyright
 |   protection and is in the public domain.
 |
 |   We would appreciate acknowledgement if the software is used.
 |
*/

/*
 | Project:     WCDMA simulation environment
 | Module:	WCDMA rake receiver
 | Author: 	Maarit Melvasalo/NIST and
 |              Tommi Makelainen /Nokia Research Center
 | Date:        February 12, 1999
 |
 | History:
 |              February 20, 1999 
 |                      Initial version.
 |
 |              April 7, 1999 
 |		Modified finger processing and restructured 
 |		algorithm.
 |
 |              May 7, 1999 Tommi Makelainen
 |                      Corrected indexing error in finger combining.
 |
 |              May 20, 1999 Tommi Makelainen
 |                      Corrected indexing error in spreading of
 |                      delayed chips.
 |                      If channel changes, finger allocation 
 |                      now changes allocation after FAST_FADE_TIME
 |                      slots.
 |
 */

#ifndef RAKE_H
#define RAKE_H

/* ------------ D E F I N E S ---------------------------------------- */

/*
 * Maximum number of slots that allocated channel tap can
 * be non-existing before the finger is released.
 */
#define FAST_FADE_TIME 2

/*
 * Maximum change in tap location (in chip/10).
 */
#define CHANNEL_TAP_DRIFT 0

/*
 * Threshold to for tap amplitude level to select finger.
 */
#define FINGER_ALLOC_THRESHOLD 0.001

#if 0
/*
 * Max spreading factor.
 */
#define MAX_SPREADING_FACTOR 256
#endif

/*
 * Maximum number of channel taps.
 */
#define MAX_CHANNEL_LEN MAX_CHANNEL_TAPS

/*
 * Maximum number of fingers.
 */
#define MAX_FINGERS MAX_CHANNEL_LEN

/*
 * Maximum number of receiver output symbols (soft bits).
 */
#define MAX_OUTPUT_SYMBOLS 6000
#define FINGER_OUT_BUFFER 2*MAX_OUTPUT_SYMBOLS

/*
 * Maximum number of rake receivers in simulation.
 */
#ifndef MAX_RAKES
#define MAX_RAKES 4
#endif /* MAX_RAKES */


/* ------------ D A T A   T Y P E S ---------------------------------- */

/*
 * Data type for each finger.
 */
struct rake_finger_type {
    int delay;			/* finger delay in chips */
    double amplitude;		/* relative tap amplitude (0-1) */
    double weight;		/* weight of finger output */ /* optional */
    int status;			/* -1 = not allocated, 0 = active,
                                   >0 = N block times not on its place
                                   in channel estimate. */
    int old_chips;  	        /* old chips affecting the current output */
    double output[FINGER_OUT_BUFFER]; /* finger output symbols */
    int nOutputs;               /* number of available output */
    int fill_index;             /* index to put next output symbols */
    int combine_index;          /* index to put next output symbols */
};
typedef struct rake_finger_type finger_type;

/*
 * Data type to store unused chips from previous function call.
 */
struct old_chips_type {
    int len;				/* Number of old samples saved */
    double chips[MAX_SPREADING_FACTOR];	/* old chips */
};
typedef struct old_chips_type mem_chips_t;

/*
 * Misc. data related to rake receiver.
 */
struct rake_misc_data_t {
    int min_delay;	/* delay of shortest path in fingers */
    int max_delay;	/* delay of longest path in fingers */
    int output_symbols;	/* number of soft bits we on this round */
};
typedef struct rake_misc_data_t rake_data_type;

/*
 * Misc. debug related data.
 */
#define DEBUG_DATA_LEN 10
int debug_data[DEBUG_DATA_LEN];

/* ------------------------------------------------------------------- */

int wcdma_rake_init(
        int pilot_len,          /* IN: length of pilot in a slot, in chips */
        double finger_inc_level,/* IN: finger selection threshold */
        int nFingers);          /* IN: amount of fingers to use */

int wcdma_rake_finger_alloc(		
	int instance,		/* IN: rake instance number */
        int init_flag,	        /* IN: TRUE = first call, FALSE otherwise */
        int tap_delays[],	/* IN: vector of tap delays (in chips) */
        double tap_amplitudes[],  /* IN: vector of tap amplitudes (0-1) */
        int ch_len,		/* IN: number of taps in channel estimate */
        int code_len,           /* IN: length of spreading code */
        int data_len,           /* IN: length of input data vector */
        int nFingers,		/* IN: number of rake fingers to use */
        finger_type *fingers,	/* IN/OUT: vector of finger data structures */
        mem_chips_t *prev_rake_chips,  /* IN: data for old chips in memory */
        rake_data_type *misc_data);  /* OUT: rake data */

int wcdma_rake_symbol_direct(
	int finger_id,		/* IN: id number of current finger */
        double input[],		/* IN: input received samples */
        int in_len,		/* IN: length of input vector */
        int code[],		/* IN: spreading code */
        int code_len,		/* IN: length of spreading code */
        finger_type *fingers,	/* IN/OUT: vector of finger data structures */
        mem_chips_t *prev_samples);  /* IN: old saved samples */

int wcdma_rake_symbol_delayed(
	int finger_id,		/* IN: id number of current finger */
        double input[],		/* IN: input received samples */
        int in_len,		/* IN: length of input vector */
        int code[],		/* IN: spreading code */
        int code_len,		/* IN: length of spreading code */
        finger_type *fingers,	/* IN/OUT: vector of finger data structures */
        mem_chips_t *prev_samples);  /* IN: old saved samples */

int wcdma_rake_finger_memory_save(
        double *input,		/* IN: input received samples */
        int in_len,             /* IN: input length */
        int code_len,           /* IN: spreading code length */
        mem_chips_t *prev_samples);  /* IN/OUT: old saved samples */

int wcdma_rake_fingers_combine(
        finger_type *fingers,	/* IN: vector of finger data structures */
        int nFingers,		/* IN: number of fingers to combine */
        double output[],	/* OUT: output symbols */
        int *nOutputs);         /* OUT: length of output vector */

int wcdma_rake_receiver(
        int instance,		/* IN: instance number */
        double data[], 		/* IN: input data symbol vector */
        int data_len,  		/* IN: length of input data vector */
        int code[],    		/* IN: spreading code vector */
        int code_len,  		/* IN: length of spreading code */
        int sf,        		/* IN: Chip/data rate, i.e. spreading factor */
        int ch_delays[], 	/* IN: Channel estimate */
        double ch_amplitudes[], /* IN: Channel estimate */
        int ch_len,    		/* IN: Channel estimate */
        int *out_len, 		/* OUT: Number of of output symbols */
        int *out_delay,		/* OUT: Tx to Rx delay in chips */
        double out[]); 		/* OUT: desreaded output symbol vector */
	
#endif /* RAKE_H */