pdm_ecc.ps.c

用OPNET实现802.11MAC协议DCF协议

/* dra_ecc.ps.c */
/* Default error correction model for radio link Transceiver Pipeline */

/****************************************/
/*		  Copyright (c) 1993-2002		*/
/*		by OPNET Technologies, Inc.		*/
/*		(A Delaware Corporation)		*/
/*	7255 Woodmont Av., Suite 250  		*/
/*     Bethesda, MD 20814, U.S.A.       */
/*			All Rights Reserved.		*/
/****************************************/

#include "opnet.h"


#if defined (__cplusplus)
extern "C"
#endif
void
pdm_ecc (Packet * pkptr)
    {
	int				num_colls, accept;
	OpT_Packet_Size	pklen;
	Objid			rx_ch_obid; 
	double			ecc_thresh;

	/** Determine acceptability of given packet at receiver. **/
	FIN (dra_ecc (pkptr));

	/* Do not accept packets that were received	*/
	/* when the node was disabled.				*/
	if (op_td_is_set (pkptr, OPC_TDA_RA_ND_FAIL))
		accept = OPC_FALSE;
	else
		{
	     	/* Obtain the number of collisions a packet has experienced */
    		num_colls = op_td_get_int (pkptr, OPC_TDA_RA_NUM_COLLS);
	
			/*Accept the packet if it hasn't suffered any collisions*/
		    if (num_colls == 0)
	    		accept = OPC_TRUE;
    	  	else
		    	accept = OPC_FALSE;
		}

	/* Place flag indicating accept/reject in transmission data block. */
	op_td_set_int (pkptr, OPC_TDA_RA_PK_ACCEPT, accept);

	/* In either case the receiver channel is no longer locked. */
	rx_ch_obid = op_td_get_int (pkptr, OPC_TDA_RA_RX_CH_OBJID);
	op_ima_obj_attr_set (rx_ch_obid, "signal lock", OPC_BOOLINT_DISABLED);

	FOUT
	}