LTE 网络UE端测量

在LTE网络产生切换时首先需要激活UE端丈量进程，UE端用户可采取以下方法实现：

1 直接通过eNB的RRC实体实现（也是本文介绍）

2 通过已有切换算法配置丈量

3 开发新的切换算法并对其配置

首先需要研究丈量的内容是甚么，NS3通过LteRrcSap::ReportConfigEutra说明：

  struct ThresholdEutra
  {
    enum
    {
      THRESHOLD_RSRP, ///< RSRP is used for the threshold.
      THRESHOLD_RSRQ ///< RSRQ is used for the threshold.
    } choice;
    uint8_t range; ///< Value range used in RSRP/RSRQ threshold.
  };
 struct ReportConfigEutra
  {
    enum
    {
      EVENT,
      PERIODICAL
    } triggerType;

    enum
    {
      EVENT_A1, ///< Event A1: Serving becomes better than absolute threshold.
      EVENT_A2, ///< Event A2: Serving becomes worse than absolute threshold.
      EVENT_A3, ///< Event A3: Neighbour becomes amount of offset better than PCell.
      EVENT_A4, ///< Event A4: Neighbour becomes better than absolute threshold.
      EVENT_A5 ///< Event A5: PCell becomes worse than absolute `threshold1` AND Neighbour becomes better than another absolute `threshold2`.

    } eventId; ///< Choice of E-UTRA event triggered reporting criteria.

    ThresholdEutra threshold1; ///< Threshold for event A1, A2, A4, and A5.
    ThresholdEutra threshold2; ///< Threshold for event A5.

    /// Indicates whether or not the UE shall initiate the measurement reporting procedure when the leaving condition is met for a cell in `cellsTriggeredList`, as specified in 5.5.4.1 of 3GPP TS 36.331.
    bool reportOnLeave;

    /// Offset value for Event A3. An integer between ⑶0 and 30. The actual value is (value * 0.5) dB.
    int8_t a3Offset;

    /// Parameter used within the entry and leave condition of an event triggered reporting condition. The actual value is (value * 0.5) dB.
    uint8_t hysteresis;

    /// Time during which specific criteria for the event needs to be met in order to trigger a measurement report.
    uint16_t timeToTrigger;

    enum
    {
      REPORT_STRONGEST_CELLS,
      REPORT_CGI
    } purpose;

    enum
    {
      RSRP, ///< Reference Signal Received Power
      RSRQ ///< Reference Signal Received Quality
    } triggerQuantity; ///< The quantities used to evaluate the triggering condition for the event, see 3GPP TS 36.214.

    enum
    {
      SAME_AS_TRIGGER_QUANTITY,
      BOTH ///< Both the RSRP and RSRQ quantities are to be included in the measurement report.
    } reportQuantity; ///< The quantities to be included in the measurement report, always assumed to be BOTH.

    /// Maximum number of cells, excluding the serving cell, to be included in the measurement report.
    uint8_t maxReportCells;

    enum
    {
      MS120,
      MS240,
      MS480,
      MS640,
      MS1024,
      MS2048,
      MS5120,
      MS10240,
      MIN1,
      MIN6,
      MIN12,
      MIN30,
      MIN60,
      SPARE3,
      SPARE2,
      SPARE1
    } reportInterval; ///< Indicates the interval between periodical reports.

    /// Number of measurement reports applicable, always assumed to be infinite.
    uint8_t reportAmount;

    ReportConfigEutra ();

  }; // end of struct ReportConfigEutra

ReportConfigEutra结构体定义了：

1 触发丈量报告的类型   2 事件等级  3 不同等级事件下阈值  4是不是初始化丈量报告进程  5 A3事件偏移值  6 进入或离开事件触发状态时所用参数

7 触发时间 8 目的 9 用于评价触发状态的触发量 10  报告量  11 最大报告的小区数目 12 周期报告的报告间隔 13 丈量报告数目

将ReportConfigEutra结构体作为函数LteEnbRrc::AddUeMeasReportConfig的参数，见src/lte/model/lte-enb-rrc.cc便可。

举例：

LteRrcSap::ReportConfigEutra config;
config.eventid=LteRrcSap::ReportConfigEutra::EVENT_A1;
config.threshold1.choice=LteRrcSap::ReportConfigEutra::THRESHOLD_RARP;
config.threshold1.range=41;
config.triggerQuantity=LteRrcSap::ReportConfigEutra::RSRP;
config.reportInterval=LteRrcSap::ReportConfigEutra::MS480;
//配置对象初始化
std::vector<uint8_t> measIdList;
NetDeviceContainer::Iterator it;
for(it=devs.Begin();it!=devs.End();it++)
{Ptr<NetDevice> dev=*it;
Ptr<LteEnbNetDevice>endDev=dev->GetObject<LteEnbNetDevice>();
Ptr<LteEnbRrc>enbRrc=enbDev->GetRrc();
uint8_t measId=enbRrc->AddUeMeasReportConfig(config);//调用
measIdList.push_back(measId);//存储已有的measId
rnbRrc->TraceConnect("RecvMeasurementReport",
                                  "context",
                                  MakeCallback("&RecvMeasurementReportCallback"));//
 }

生活不易，码农辛苦
如果您觉得本网站对您的学习有所帮助,可以手机扫描二维码进行捐赠