CDMA_Channel.c

/************************************************************************************
 * Copyright (C) 2023                                                               *
 * 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 "CDMA.h"
#include "Cellular.h"
 
/**
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    This function is used to form the CDMA channel based on the following
    assumption.
        1. One call class : All MS requires same target SNR
        2. Co-located MS: MS are uniformly distributed on area covered by BTS.
        3. Hard handover
    max number of call handle is given by formula below 
    
    dProcessingGain = (BSMac->CDMAVar.dChipRate)/dCDMA_DATARATE*1.0
    dTau = BSMac->CDMAVar.dChipRate/dProcessingGain*1.0
    dMaxNoOfCallHandled = 1.0/(1+dNeu)
    dMaxNoOfCallHandled *= (1+dTau)/dTau
    dMaxNoOfCallHandled = dMaxNoOfCallHandled/BSMac->CDMAVar.dVoiceActivityFactor
 
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
_declspec(dllexport) int fn_NetSim_FormCDMAChannel(NETSIM_ID nBTSId,Cellular_BS_MAC* BSMac,int nCDMA_ETA,int nCDMA_SIGMA,double dCDMA_DATARATE)
{
    static int nChannelId=1;
    Cellular_CHANNEL *tempChannel1,*tempChannel2; //Temp channel used for assignment
    int nLoop1; //Loop counter
    int nMaxNoOfCallHandled; //Max number of call handled by the CDMA system
    double dMaxNoOfCallHandled;
    double dNeu; //Path loss exponent
    double dTau; //desired lower bound of SNR
    double dTemp; // Temp for calculation channel number
    double dPower; // Power used to calculate other cell interference
    double dProcessingGain; //Processing gain of CDMA system
    double dCDMA_TARGETSNR=BSMac->CDMAVar.dTargetSNR;
 
 
    if(nCDMA_SIGMA==0)
        nCDMA_SIGMA=12;
    /* Calculate the other cell interface factor based on
     * the path loss exponent. The value are taken from the
     * book "CDMA: Principles of spread spectrum" by Andy Viterbe.
     */
    switch(nCDMA_ETA)
    {
    default:
    case 3:
        dTemp = 0.77;
        break;
    case 4:
        dTemp = 0.44;
        break;
    case 5:
        dTemp = 0.30;
        break;
    }
 
    dPower = nCDMA_SIGMA* nCDMA_SIGMA/2.0;
    dPower = dPower*log(10)*log(10)/100.0;
    dNeu = pow(2.71828,dPower);
    dNeu *= dTemp;
    dCDMA_TARGETSNR = pow(10,dCDMA_TARGETSNR/10.0);
 
    //Calculate the processing gain = Chip rate/Data rate
    dProcessingGain = (BSMac->CDMAVar.dChipRate)/dCDMA_DATARATE*1.0;
    dTau = BSMac->CDMAVar.dChipRate/dProcessingGain*1.0;
    dMaxNoOfCallHandled = 1.0/(1+dNeu);
    dMaxNoOfCallHandled *= (1+dTau)/dTau;
    dMaxNoOfCallHandled = dMaxNoOfCallHandled/BSMac->CDMAVar.dVoiceActivityFactor;
    nMaxNoOfCallHandled = (int)ceil(dMaxNoOfCallHandled);
    for(nLoop1=0;nLoop1<nMaxNoOfCallHandled;nLoop1++)
    {
        //Assigning memory for temporary channel
        tempChannel1 = calloc(1,sizeof* tempChannel1);
        tempChannel1->nAllocationFlag=0; // Initially all channel is free
        tempChannel1->nChannelId = nChannelId++;
        tempChannel1->nBTSId=nBTSId;
        if(nLoop1 == 0) // First Channel (Pilot channel)
        {
            // Setting first channel of BTS (Pilot channel) = Temporary channel
            BSMac->pstruChannelList = tempChannel1;
            tempChannel1->nChannelType = ChannelType_Pilot; // First channel is pilot channel
            tempChannel2=tempChannel1;
        }
        else // All channel except first (Traffic channel).
        {
            // Appending temporary channel to BTS channel list for Traffic channel
            tempChannel1 ->nChannelType = ChannelType_TRAFFICCHANNEL;
            tempChannel2->pstru_NextChannel = tempChannel1;
            tempChannel2 = tempChannel1;
        }
    }
    BSMac->nAllocatedChannel = 0; // Initially no channel is busy
    BSMac->nRACHChannel=1;
    BSMac->nFreeChannel=nMaxNoOfCallHandled;    // Initially all channel is free
    BSMac->nTrafficChannel=nMaxNoOfCallHandled-1;
    BSMac->nChannelCount = nMaxNoOfCallHandled; // Total number of channel
    return 1;
}