/* -*- mode:c++ -*- ********************************************************
 * file:        AsyncSnrEval.h
 *
 * author:      Yupeng.hu
 *
 * copyright:   (C) 2006 HUNAN Universtiy, ChangSha China
 *
 ***************************************************************************
 * part of:     Async Simulation
 * description: - Async Description
 *
 ***************************************************************************
 * changelog:   $Revision$
 *              last modified:   $Date: 2006-7-13 12:57 $
 *              by:              $Author: Yupeng.hu $
 ***************************************************************************/
 
 
#ifndef SYNCSNR_EVAL_H
#define SYNCSNR_EVAL_H

#include <BasicSnrEval.h>

#include "RadioState.h"

/**
 * @brief Keeps track of the different snir levels when receiving a
 * packet
 *
 * This module keeps track of the noise level of the channel.
 *
 * When receiving a packet this module updates the noise level of the
 * channel. Based on the receive power of the packet it is processed
 * and handed to upper layers or just treated as noise.
 *
 * After the packet is completely received the snir information is
 * attached and it is handed to the deceider module.
 *
 * The snir information is a SnrList that lists all different snr
 * levels together with the point of time (simTime()) when they
 * started. 
 *
 * On top of that this module publishes the RadioState on the
 * Blackboard. The radio state gives information about whether this
 * module is sending a packet, receiving a packet or idle. This
 * information can be accessed via the Blackboard by other modules,
 * e.g. a CSMAMacLayer. 
 **/
class AsyncSnrEval : public BasicSnrEval
{
	Module_Class_Members( AsyncSnrEval, BasicSnrEval, 0 );

public:
	/** @brief Initialize variables and publish the radio status*/
  	virtual void initialize(int);

  	virtual void finish();

protected:
    virtual void handleUpperMsg(AirFrame*);

    virtual void handleSelfMsg(cMessage*);

    /**\brief Buffer the frame and update noise levels and snr information...*/
    virtual void handleLowerMsgStart(AirFrame*);

    /**\brief Unbuffer the frame and update noise levels and snr information*/
    virtual void handleLowerMsgEnd(AirFrame*);

    /**\brief Calculates the power with which a packet is received.*/
    double calcRcvdPower(double pSend, double distance);

    /**\brief updates the snr information of the relevant AirFrames*/
    void addNewSnr();

protected:

  	/** @brief Enum to store self message kind()s*/
  	enum
    {
    	/** @brief timer to indicate that a message is completely sent now*/
      	TRANSM_OVER
    };

  	/**
   	* @brief Struct to store a pointer to the mesage, rcvdPower AND a
   	* SnrList, needed in AsyncSnrEval::addNewSnr
  	**/
  	struct SnrStruct{
    	/** @brief Pointer to the message this information belongs to*/
    	AirFrame* ptr;
    	/** @brief Received power of the message*/
    	double rcvdPower;
    	/** @brief Snr list to store the SNR values*/
    	SnrList sList;
  	};

  	/**
   	* @brief SnrInfo stores the snrList and the the recvdPower for the
   	* message currently beeing received together with a pointer to the
	* message.
	**/
  	SnrStruct snrInfo;

  	/**
   	* @brief Typedef used to store received messages together with
   	* receive power.
   	**/
  	typedef std::map<AirFrame*,double> cRecvBuff;

  	/**
   	* @brief A buffer to store a pointer to a message and the related
   	* receive power.
   	**/
   	cRecvBuff recvBuff;

  	/** @brief Reference to the RadioState*/
  	BBItemRef bbRs;

  	/** @brief Actual RadioState of the nic*/
  	RadioState* rs;

  	/**\brief The noise level of the channel.*/
  	double noiseLevel;

  	/**
   	* @brief The carrier frequency used.Can be specified in the
   	* omnetpp.ini file. If not it is read from the ChannelControl
   	* module.
   	**/
  	double carrierFrequency;
  	
  	int colliscount;
  
  	/** 
   	* @brief Thermal noise on the channel. Can be specified in
   	* omnetpp.ini. Default: -100 dBm
   	**/
  	double thermalNoise;

  	/**
   	* @brief Defines up to what Power level (in dBm) a message can be
   	* understood. If the level of a received packet is lower, it is
   	* only treated as noise. Can be specified in omnetpp.ini. Default:
   	* -85 dBm
   	**/
  	double sensitivity;

  	/**
   	* @brief Path loss coefficient. Can be specified in omnetpp.ini. If
   	* not it is read from the ChannelControl module. This value CANNOT
   	* be smaller than the one specified in the ChannelControl
   	* module. The simulation will exit with an error!
   	**/
  	double pathLossAlpha;


};

#endif