如何用.cc源文件修改Omnet++/INET模块行为实现定向天线扇区搜索

核心修改思路 #

无需修改adhocHost核心代码，通过扩展移动性模块和添加自定义天线检测模块实现需求，避免破坏INET原有模型的兼容性。

1. 自定义扇区扫描移动性模块 #

替换LinearMobility，编写SectorScanMobility.cc/.h实现定时切换航向角的逻辑：

• 头文件定义核心参数：扇区数M、单扇区停留时间scanDuration、初始航向角initialHeading、扇区角度间隔sectorAngle = 360/M
• initialize()中启动定时器，首次触发延迟设为0
• 定时器触发时，顺时针计算下一扇区航向角（超过360取模），直接修改heading变量后重置定时器
• 保持速度为0，确保主机位置固定，仅切换天线指向

示例代码片段（.cc）：

#include "inet/mobility/base/MovingMobilityBase.h"

using namespace inet;

class SectorScanMobility : public MovingMobilityBase {
  protected:
    int numSectors;
    simtime_t scanTime;
    double sectorAngle;
    int currentSector = 0;
    cMessage *scanTimer = nullptr;

    virtual void initialize(int stage) override {
        MovingMobilityBase::initialize(stage);
        if (stage == INITSTAGE_LOCAL) {
            numSectors = par("numSectors");
            scanTime = par("scanTime");
            sectorAngle = 360.0 / numSectors;
            scanTimer = new cMessage("scanTimer");
            scheduleAt(simTime(), scanTimer);
        }
    }

    virtual void handleSelfMessage(cMessage *msg) override {
        if (msg == scanTimer) {
            currentSector = (currentSector + 1) % numSectors;
            heading = initialHeading + currentSector * sectorAngle;
            emit(headingChangedSignal, heading);
            scheduleAt(simTime() + scanTime, scanTimer);
        }
        else
            MovingMobilityBase::handleSelfMessage(msg);
    }

    virtual void finish() override {
        cancelAndDelete(scanTimer);
        MovingMobilityBase::finish();
    }
};

Define_Module(SectorScanMobility);

在NED文件注册模块并替换原移动性组件：

module SectorScanMobility extends inet.mobility.base.MovingMobilityBase {
    parameters:
        int numSectors = default(8);
        simtime_t scanTime = default(1s);
        @class(SectorScanMobility);
}

2. 天线检测与信息存储 #

在主机内添加AntennaScanner.cc/.h模块，绑定定向天线信号监听邻居：

• 依赖INET的IRadioListener接口，订阅receptionStarted信号
• 检测到其他天线信号时，获取发送方主机名、自身当前航向角，存储到本地std::map结构
• 检测信息可通过EV输出，或传递给上层MAC模块为后续扩展做准备

示例代码片段：

#include "inet/physicallayer/wireless/common/contract/packetlevel/IRadio.h"
#include "inet/physicallayer/wireless/common/radio/Radio.h"

using namespace inet;

class AntennaScanner : public cSimpleModule, public IRadioListener {
  protected:
    Radio *radio = nullptr;
    std::map<std::string, double> detectedAntennas;

    virtual void initialize(int stage) override {
        cSimpleModule::initialize(stage);
        if (stage == INITSTAGE_LOCAL) {
            radio = getModuleFromPar<Radio>(par("radioModule"), this);
            radio->addListener(this);
        }
    }

    virtual void receiveSignal(cComponent *source, simsignal_t signalID, cObject *obj, cObject *details) override {
        if (signalID == IRadio::receptionStartedSignal) {
            auto radioSignal = check_and_cast<RadioSignal *>(obj);
            auto senderHost = findContainingNode(radioSignal->getTransmitter()->getOwner());
            std::string hostName = senderHost->getName();
            auto mobility = getModuleFromPar<IMobility>(par("mobilityModule"), this);
            double currentHeading = mobility->getHeading();
            detectedAntennas[hostName] = currentHeading;
            EV_INFO << "Detected antenna from " << hostName << " at heading " << currentHeading << endl;
        }
    }
};

Define_Module(AntennaScanner);

在adhocHost的NED定义中添加该模块：

module ExtendedAdhocHost extends inet.node.adhoc.AdhocHost {
    submodules:
        antennaScanner: AntennaScanner {
            parameters:
                radioModule = "^.wlan[0].radio";
                mobilityModule = "^.mobility";
        }
}

3. .ini文件配置 #

• 使用自定义ExtendedAdhocHost替代原生adhocHost
• 配置扇区扫描参数：

*.host*.mobility.type = "SectorScanMobility"
*.host*.mobility.numSectors = 6
*.host*.mobility.scanTime = 2s
*.host*.mobility.initialHeading = 0deg
*.host*.mobility.speed = 0m/s

4. 状态机集成 #

将现有状态机逻辑整合到AntennaScanner或单独模块中：

• 用cFSM类管理扫描、检测、握手等状态切换
• 检测到目标天线后，触发自定义控制报文实现握手逻辑

注意事项 #

• 确保定向天线beamWidth参数设置为360/M，使单扇区匹配波束范围
• 测试阶段可关闭MAC层自动连接，先验证扫描与检测逻辑
• 后续扩展MAC层时，直接读取AntennaScanner存储的天线信息即可

内容的提问来源于stack exchange，提问作者Drew.Lam