Aloha_Phy.c

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/************************************************************************************
 * Copyright (C) 2020                                                               *
 * TETCOS, Bangalore. India                                                         *
 *                                                                                  *
 * Tetcos owns the intellectual property rights in the Product and its content.     *
 * The copying, redistribution, reselling or publication of any or all of the       *
 * Product or its content without express prior written consent of Tetcos is        *
 * prohibited. Ownership and / or any other right relating to the software and all  *
 * intellectual property rights therein shall remain at all times with Tetcos.      *
 *                                                                                  *
 * Author:    Shashi Kant Suman                                                     *
 *                                                                                  *
 * ---------------------------------------------------------------------------------*/
#include "main.h"
#include "Aloha.h"
#include "Aloha_enum.h"
#include "../UWAN/UWAN.h"
 
typedef struct stru_packetList
{
    NetSim_PACKET* head;
    NetSim_PACKET* tail;
}PACKETLIST, *ptrPACKETLIST;
 
PACKETLIST txPacketList;
 
static void add_packet_to_txList(NetSim_PACKET* packet)
{
    if (txPacketList.head)
    {
        txPacketList.tail->pstruNextPacket = packet;
        txPacketList.tail = packet;
    }
    else
    {
        txPacketList.head = packet;
        txPacketList.tail = packet;
    }
}
 
static void remove_packet_from_txList(NetSim_PACKET* packet)
{
    NetSim_PACKET* t = txPacketList.head;
    NetSim_PACKET* p = NULL;
    while (t)
    {
        if (t == packet)
        {
            if (p)
            {
                p->pstruNextPacket = t->pstruNextPacket;
                if (!t->pstruNextPacket)
                    txPacketList.tail = p;
            }
            else
            {
                txPacketList.head = t->pstruNextPacket;
                if (!t->pstruNextPacket)
                    txPacketList.tail = NULL;
            }
            break;
        }
        t = t->pstruNextPacket;
    }
    packet->pstruNextPacket = NULL;
}
 
static void mark_packet_for_collision()
{
    NetSim_PACKET* p = txPacketList.head;
    while (p)
    {
        PALOHA_PHY_VAR phy = ALOHA_PHY(p->nReceiverId, 1);
        
        double power = get_received_power(p->nTransmitterId, p->nReceiverId, p->pstruPhyData->dArrivalTime);
        double interference = substract_power_in_dbm(phy->dInterferencePower, power);
 
        if ( interference > phy->rx_sensitivity)
            p->nPacketStatus = PacketStatus_Collided;
 
        p = p->pstruNextPacket;
    }
}
 
static void update_interference_power(NETSIM_ID tx,
                                      NETSIM_ID rx,
                                      double time,
                                      bool isAdd)
{
    rx;
    NETSIM_ID i;
    PALOHA_PHY_VAR phy;
    for (i = 0; i < NETWORK->nDeviceCount; i++)
    {
        if (i + 1 == tx)
            continue;
 
        phy = ALOHA_PHY(i + 1, 1);
        double p = phy->dInterferencePower;
        if (isAdd)
            phy->dInterferencePower = add_power_in_dbm(p,
                                                       get_received_power(tx, i + 1, time));
        else
            phy->dInterferencePower = substract_power_in_dbm(p,
                                                             get_received_power(tx, i + 1, time));
    }
}
 
static double calulate_transmission_time(NetSim_PACKET* packet)
{
    double size=fnGetPacketSize(packet);
    NETSIM_ID source=packet->nTransmitterId;
    PALOHA_PHY_VAR phy = ALOHA_PHY(source,1);
    double dDataRate=phy->data_rate;
    double dTxTime= size*8.0/dDataRate;
    return dTxTime;
}
 
static double calculate_propagation_delay(NetSim_PACKET* packet)
{
    NETSIM_ID source = packet->nTransmitterId;
    NETSIM_ID destination = packet->nReceiverId;
    double dPropagationDelay = UWAN_calculate_propagation_delay(source, 1,
                                                                destination, 1,
                                                                get_aloha_propagation_info(source, destination));
    return dPropagationDelay;
}
 
static void transmit_packet(NetSim_PACKET* packet, bool* flag)
{
    PALOHA_PHY_VAR phy = ALOHA_PHY(packet->nReceiverId,1);
    PALOHA_PHY_VAR phyt = ALOHA_PHY(packet->nTransmitterId,1);
    double power = get_received_power(packet->nTransmitterId, packet->nReceiverId,
                                      packet->pstruPhyData->dArrivalTime);
    
    phyt->transmitter_status = TRX_ON_BUSY;
 
    if(power < phy->rx_sensitivity)
        packet->nPacketStatus=PacketStatus_Error;
 
    //Add physical in event
    pstruEventDetails->dEventTime=packet->pstruPhyData->dEndTime;
    packet->pstruPhyData->dEndTime = pstruEventDetails->dEventTime;
    pstruEventDetails->dPacketSize=packet->pstruPhyData->dPacketSize;
    pstruEventDetails->nDeviceId=packet->nReceiverId;
    pstruEventDetails->nDeviceType=DEVICE_TYPE(packet->nReceiverId);
    pstruEventDetails->nEventType=PHYSICAL_IN_EVENT;
    pstruEventDetails->nInterfaceId=1;
    pstruEventDetails->pPacket=packet;
    fnpAddEvent(pstruEventDetails);
    
    add_packet_to_txList(packet);
    if (!*flag)
        update_interference_power(packet->nTransmitterId,
                                  packet->nReceiverId,
                                  packet->pstruPhyData->dArrivalTime,
                                  true);
    *flag = true;
    mark_packet_for_collision();
}
 
int fn_NetSim_Aloha_PhyOut()
{
    double dTxTime;
    double dPropagationDelay;
    NetSim_PACKET* packet= pstruEventDetails->pPacket;
    packet->pstruPhyData->dArrivalTime=pstruEventDetails->dEventTime;
    packet->pstruPhyData->dPayload=packet->pstruMacData->dPacketSize;
    packet->pstruPhyData->dOverhead=ALOHA_PHY_OVERHEAD;
    packet->pstruPhyData->dPacketSize=packet->pstruPhyData->dOverhead+packet->pstruPhyData->dPayload;
    packet->pstruPhyData->dStartTime=pstruEventDetails->dEventTime;
 
    bool flag = false;
    if(packet->nReceiverId)
    {
        dTxTime = calulate_transmission_time(packet);
        dPropagationDelay = calculate_propagation_delay(packet);
        packet->pstruPhyData->dStartTime = packet->pstruPhyData->dArrivalTime + dTxTime;
        packet->pstruPhyData->dEndTime = packet->pstruPhyData->dStartTime + dPropagationDelay;
        transmit_packet(packet, &flag);
    }
    else
    {
        //Broadcast packet
        NETSIM_ID loop;
        for(loop=0;loop<NETWORK->nDeviceCount;loop++)
        {
            if(loop+1!=packet->nTransmitterId)
            {
                NetSim_PACKET* p = fn_NetSim_Packet_CopyPacket(packet);
                //Add physical in event
                p->nReceiverId=loop+1;
                dTxTime = calulate_transmission_time(p);
                dPropagationDelay = calculate_propagation_delay(p);
                p->pstruPhyData->dEndTime = p->pstruPhyData->dArrivalTime + dTxTime;
                p->pstruPhyData->dEndTime = p->pstruPhyData->dStartTime + dPropagationDelay;
                transmit_packet(p, &flag);
            }
        }
        fn_NetSim_Packet_FreePacket(packet);
    }
    return 0;
}
 
static void notify_src(NETSIM_ID tx,
                       bool isError)
{
    double acktime = 0;
    NetSim_EVENTDETAILS pevent;
    memset(&pevent, 0, sizeof pevent);
    pevent.dEventTime = pstruEventDetails->dEventTime + acktime;
    pevent.nDeviceId = tx;
    pevent.nDeviceType = DEVICE_TYPE(tx);
    pevent.nEventType = MAC_OUT_EVENT;
    pevent.nInterfaceId = 1;
    pevent.nProtocolId = MAC_PROTOCOL_ALOHA;
    pevent.nSubEventType = isError ? ALOHA_PACKET_ERROR : ALOHA_PACKET_SUCCESS;
    fnpAddEvent(&pevent);
}
 
void fn_NetSim_Aloha_PhyIn()
{
    PALOHA_PHY_VAR phy = ALOHA_CURR_PHY;
    double ber;
    NetSim_PACKET* packet = pstruEventDetails->pPacket;
    NETSIM_ID tx = packet->nTransmitterId;
    NETSIM_ID rx = packet->nReceiverId;
 
    if (isBroadcastPacket(packet))
    {
        if ((tx == 1 && rx == 2) ||
            rx == 1)
            update_interference_power(tx, rx,
                                      packet->pstruPhyData->dArrivalTime, false);
    }
    else
    {
        update_interference_power(tx, rx,
                                  packet->pstruPhyData->dArrivalTime, false);
    }
 
    remove_packet_from_txList(packet);
 
    if(pstruEventDetails->pPacket->nPacketStatus == PacketStatus_Collided)
        goto RET_PHYIN;
 
    ber = UWAN_Calculate_ber(tx, rx,
                             get_aloha_propagation_info(tx, rx),
                             get_received_power(tx, rx, packet->pstruPhyData->dArrivalTime),
                             phy->modulation,
                             phy->data_rate * 1000,
                             phy->bandwidth * 1000);
 
    packet->nPacketStatus = fn_NetSim_Packet_DecideError(ber, packet->pstruPhyData->dPacketSize);
 
    if(packet->nPacketStatus == PacketStatus_Error)
        goto RET_PHYIN;
 
    pstruEventDetails->nEventType = MAC_IN_EVENT;
    fnpAddEvent(pstruEventDetails);
 
RET_PHYIN:
    fn_NetSim_WritePacketTrace(packet);
    fn_NetSim_Metrics_Add(packet);
 
    if (pstruEventDetails->pPacket->nPacketStatus != PacketStatus_NoError)
    {
        notify_src(tx, true);
        fn_NetSim_Packet_FreePacket(packet);
    }
    else
    {
        notify_src(tx, false);
    }
}