wlan_ecc.ps.c

在OPNET中实现AODV路由协议

/* wlan_ecc.ps.c */
/* Modified for IEEE802.11										*/		 
/* Error correction model for radio link Transceiver Pipeline 	*/

/****************************************/
/*		  Copyright (c) 1993			*/
/*			by MIL 3, Inc.				*/
/*		(A Delaware Corporation)		*/
/*	3400 International Drive,  N.W.		*/
/*		Washington, D.C., U.S.A.		*/
/*			All Rights Reserved.		*/
/****************************************/

#include <opnet.h>

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

	/** Determine acceptability of given packet at receiver. **/
	FIN (wlan_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 error correction threshold of the receiver. */
		ecc_thresh = op_td_get_dbl (pkptr, OPC_TDA_RA_ECC_THRESH);

		/* Obtain length of packet. */
		pklen = op_pk_total_size_get (pkptr);

		/* Obtain number of errors in packet. */
		num_errs = op_td_get_int (pkptr, OPC_TDA_RA_NUM_ERRORS);
	
		/* Test if bit errors exceed threshold. */
		if (pklen == 0)
			accept = OPC_TRUE;
		else
			accept = ((((double) num_errs) / pklen) <= ecc_thresh) ? OPC_TRUE : OPC_FALSE;
		}

	/* Place flag indicating accept/reject in the data packet control field. */
	op_pk_nfd_set (pkptr, "Accept", accept);
    
	/* Force the simulation kernel to always accpet the packet. The 			*/
	/* actual discarding of the packet will take place at the MAC layer of the  */
	/* receiving node receiving this packet.                                  	*/
	op_td_set_int (pkptr, OPC_TDA_RA_PK_ACCEPT, OPC_TRUE);

	/* 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;
	}