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修改wlan_propdel��道�E�序调整无线通信半径

�q�风 — Fri, 28 May 2010 03:07:00 GMT

在做拓扑控制协议仿真�Ӟ��需要��用wlan_tx和wlan_rx�q�一�Ҏ��发机�Q��ƈ对节炚w��信半径�q�行动态调��_��但如果��用较低版本的OPNET�Q�源�E�序中可能没有对通信半径做明��限制。此时我们可以修�Ҏ��U�收发机的pipeline -> wlan_propdel��道�E�序�Q�达到动态调整通信半径的目的�?br>
�W�一步，在wlan_mac�q�程模型中，��d��Simulation Attributes -> Wireless LAN Range (meters) 属性，�c�d��为integer�Q�缺省��gؓ300�?br>
�W�二步，改动wlan_propdel��道�E�序。以某一版本的该�E�序��Z��Q?br>之前的：

#include <opnet.h>

/***** constants *****/

/* propagation velocity of radio signal (m/s) */
#define    PROP_VELOCITY    3.0E+08

/* The variable defining a maximum range across which the station can communicate (meters)    */
static double wlan_max_distance = OPC_DBL_INFINITY;

/***** pipeline procedure *****/
#if defined (__cplusplus)
extern "C"
#endif
void
Zhou_wlan_propdel (pkptr)
    Packet*        pkptr;
    {
    double        start_prop_delay, end_prop_delay;
    double        start_prop_distance, end_prop_distance;

    // Compute the propagation delay separating the
    // radio transmitter from the radio receiver.
    FIN (wlan_propdel (pkptr));

    // Get the start distance between transmitter and receiver.
    start_prop_distance = op_td_get_dbl (pkptr, OPC_TDA_RA_START_DIST);

    // Get the end distance between transmitter and receiver.
    end_prop_distance = op_td_get_dbl (pkptr, OPC_TDA_RA_END_DIST);

    // Compute propagation delay to start of reception.
    start_prop_delay = start_prop_distance / PROP_VELOCITY;

    // Compute propagation delay to end of reception.
    end_prop_delay = end_prop_distance / PROP_VELOCITY;

    // If the maximum transmission range of the station is not already set
    // then extract it from the user defined simulation attribute.
    if (wlan_max_distance == OPC_DBL_INFINITY)
        {
        if (op_ima_sim_attr_exists ("Wireless LAN Range (meters)") == OPC_TRUE)
            {
            op_ima_sim_attr_get (OPC_IMA_DOUBLE, "Wireless LAN Range (meters)", &wlan_max_distance);
            }

        //printf ("wlan_max_distance is %f \n", wlan_max_distance);
        }

        // If the starting and ending propagation distance is more than the maximum transmission
    // range then discard the packet in the pipeline stage. This will model the physical
    // transmission boundary of a wireless station.
    if (end_prop_distance > wlan_max_distance || start_prop_distance > wlan_max_distance)
        {
        // Discard the packet if the destination is more than the specified range
        op_td_set_int (pkptr, OPC_TDA_RA_MATCH_STATUS, OPC_TDA_RA_MATCH_IGNORE);
        }

        // Place both propagation delays in packet transmission data attributes.
    op_td_set_dbl (pkptr, OPC_TDA_RA_START_PROPDEL, start_prop_delay);
    op_td_set_dbl (pkptr, OPC_TDA_RA_END_PROPDEL, end_prop_delay);
    FOUT;
    }

修改之后的，注意 "if (wlan_max_distance == OPC_DBL_INFINITY)"那部分�ؓ��d��语句�Q?br>

#include <opnet.h>

/***** constants *****/

/* propagation velocity of radio signal (m/s) */
#define    PROP_VELOCITY    3.0E+08

/* The variable defining a maximum range across which the station can communicate (meters)    */
static double wlan_max_distance = OPC_DBL_INFINITY;

/***** pipeline procedure *****/
#if defined (__cplusplus)
extern "C"
#endif
void
wlan_propdel (pkptr)
    Packet*        pkptr;
    {
    double        start_prop_delay, end_prop_delay;
    double        start_prop_distance, end_prop_distance;

    // Compute the propagation delay separating the
    // radio transmitter from the radio receiver.
    FIN (wlan_propdel (pkptr));

    // Get the start distance between transmitter and receiver.
    start_prop_distance = op_td_get_dbl (pkptr, OPC_TDA_RA_START_DIST);

    // Get the end distance between transmitter and receiver.
    end_prop_distance = op_td_get_dbl (pkptr, OPC_TDA_RA_END_DIST);

    // Compute propagation delay to start of reception.
    start_prop_delay = start_prop_distance / PROP_VELOCITY;

    // Compute propagation delay to end of reception.
    end_prop_delay = end_prop_distance / PROP_VELOCITY;

    // If the maximum transmission range of the station is not already set
    // then extract it from the user defined simulation attribute.
    if (wlan_max_distance == OPC_DBL_INFINITY)
        {
        if (op_ima_sim_attr_exists ("Wireless LAN Range (meters)") == OPC_TRUE)
            {
            op_ima_sim_attr_get (OPC_IMA_DOUBLE, "Wireless LAN Range (meters)", &wlan_max_distance);
            }

        //printf ("wlan_max_distance is %f \n", wlan_max_distance);
        }

        // If the starting and ending propagation distance is more than the maximum transmission
    // range then discard the packet in the pipeline stage. This will model the physical
    // transmission boundary of a wireless station.
    if (end_prop_distance > wlan_max_distance || start_prop_distance > wlan_max_distance)
        {
        // Discard the packet if the destination is more than the specified range
        op_td_set_int (pkptr, OPC_TDA_RA_MATCH_STATUS, OPC_TDA_RA_MATCH_IGNORE);
        }

        // Place both propagation delays in packet transmission data attributes.
    op_td_set_dbl (pkptr, OPC_TDA_RA_START_PROPDEL, start_prop_delay);
    op_td_set_dbl (pkptr, OPC_TDA_RA_END_PROPDEL, end_prop_delay);
    FOUT;
    }

�W�三步，选择file -> Compile�Q�编译该�E�序。需要注意的是，如果��wlan_propdel改名为其他名字，�?**_wlan_propdel�Q�那么需要将函数名也修改为相应的***_wlan_propdel�?br>

�q�风 2010-05-28 11:07 发表评论

自动配置节点ID��L��Ҏ��

�q�风 — Wed, 27 Jan 2010 02:40:00 GMT

无线传感器或者无�U�局域网仿真需要��用wlan_mac模块作�ؓ链�\层协议，在定义大量节点的时候如果手工设�|�每个节点的wlan_mac.Address属性（mac地址�Q�是一件很�ȝ��的事情，而wlan_mac模块对该属性提供了一个Auto Assigned��|��Auto Assigned=-2�Q�，但在实际的仿真中发现�Q�设�|��ؓAuto Assigned的节点�ƈ没有自行讄��有效的mac地址�Q�而是仍�ؓ-2�Q�此时源节点只能讄��目的地址为Broadcast�Q?1�Q�或者Random�Q?2�Q��?br>�l�g��所�q�ͼ�本�h惛_��了一个方法，��wlan_mac.Address属性与name属性取值相�{�，�Q�而在��d��节点的时候，节点的name属性是自动递增的，例如��d��节点”1”后，下一个添加的节点名�ؓ”2”。这样就避免了手工设�|�的�ȝ��Q�具体如下：

在wlan_mac模块中的init函数中添加如下命令：

/* Determine the assigned MAC address.        */
op_ima_obj_attr_get (my_objid, "Address", &my_address);

//*************************************************************************
if (my_address == AUTO_ASSIGNED)
    {
    op_ima_obj_attr_get (my_node_objid, "name", my_node_name);
    my_address = name_aoti (my_node_name);
    op_ima_obj_attr_set (my_node_objid, "Wireless LAN MAC Address", my_address);
    }
//*************************************************************************

/* Obtain an address handle for resolving WLAN MAC addresses.    */
oms_aa_handle = oms_aa_address_handle_get ("MAC Addresses", "Address");

其中�Q�在SV中定义my_node_name为int型变量，在HB中定义AUTO_ASSIGNED�?2。该代码定义�Q�如果读出的my_address�?2�Q�说明mac层地址仍未讄��Q�则在此��其讄��点name��|��否则不做��M��动作�?br>
同理�Q�在其他需要��用mac层地址的协议层中的初始化部分，��d��如下代码�Q?br>

if (my_node_addr == AUTO_ASSIGNED)
    {
    op_ima_obj_attr_get (op_topo_parent (op_id_self ()), "name", my_node_name);
    my_node_addr = name_aoti (my_node_name);
    op_ima_obj_attr_set (op_topo_parent (op_id_self ()), "Wireless LAN MAC Address", my_node_addr);
    }

注意�Q?br>1.在wlan_mac_intf层，同样需要��用到mac_address�Q�但只在wait阶段需要对该属性进行读写，所以�ƈ不会��d��错误的��|��可以不管�?br>2.name_aoti函数�Q?br>

static int name_aoti (char *name)
    {
    int num = 0;
    char *tmp = name;

    FIN (name_aoti);

    while (*tmp != '\0')
        {
        num = num * 10 + *tmp - '0';
        tmp++;
        }

    FRET (num);
    }

�q�风 2010-01-27 10:40 发表评论

�q�风 — Tue, 26 Jan 2010 05:41:00 GMT

参考他��Z��码，发现在wlan_mac�q�程模型中的Simulation Attributes中定义了Wireless LAN Range (meters)属性，不知从何而来�Q�如图所�C�。经查证该属性不存在于wlan_mac�q�程代码中，疑来自底层的��道阶段代码�?br>

后来发现�Q�在wlan_port_tx.propdel model��道阶段�?span style="COLOR: red">wlan_propdel�E�序中有�q�么一�D�代码：

/* If the maximum transmission range of the station is not already set then extract    */
/* it from the user defined simulation attribute.                    */
if (wlan_max_distance == OPC_DBL_INFINITY)
    {
    if (op_ima_sim_attr_exists ("Wireless LAN Range (meters)") == OPC_TRUE)
        {
        op_ima_sim_attr_get (OPC_IMA_DOUBLE, "Wireless LAN Range (meters)", &wlan_max_distance);
        }
    }
/* If the starting and ending propagation distance is more than the maximum transmission    */
/* range then discard the packet in the pipeline stage. This will model the physical        */
/* transmission boundary of a wireless station.                            */
if (end_prop_distance > wlan_max_distance || start_prop_distance > wlan_max_distance)
    {
    op_td_set_int (pkptr, OPC_TDA_RA_MATCH_STATUS, OPC_TDA_RA_MATCH_IGNORE);
    }

该段代码的作用在于：当wlan_max_distance变量未具体定义时�Q�如果Wireless LAN Range (meters)属性在仿真属性中定义了，那么��该属性的��g��为最大的无线传输半径�Q�超�q�该传输半径的数据包通通丢弃�?br>

�q�风 2010-01-26 13:41 发表评论

�q�风 — Tue, 26 Jan 2010 02:47:00 GMT

�|�络模型�Q�无�U�传感器�|�络�Q�所有节点初始化时广播hello包�?br>节点模型�Q�在OPNET自带的wlan_station_adv节点模型基础上进行改�q�，��d��route模块。属性设�|�如下，wlan_mac_intf.destination_address <- broadcast�Q�wlan_mac.Address <- Auto Assigned�?br>仿真�l�果�Q�执行仿真运行无错误�Q�想观察�l�计�l�果时发现没有结果可昄��Q�这说明目的端接收不到数据包�Q�当把destination_address改�ؓRandom或者固定地址后，仿真�q�行无错�Q�也有统计结果显�C�，但是仍有一定量的数据包丢失�?br>
调试�U�错�Q?br>初步认定错误发生在在wlan_mac模块中，�q�一步跟�t�调试发玎ͼ�丢失数据报的原因在于执行wlan_physical_layer_data_arrival函数�Ӟ��在if ((wlan_flags->rcvd_bad_packet == OPC_BOOLINT_ENABLED) || (accept == OPC_FALSE) ||(wlan_flags->collided_packet == OPC_BOOLINT_ENABLED))判断处进入内部代码段�q�最�l�执行了op_pk_destroy函数�Q?span style="COLOR: red">说明�?/span>数据包因为在目的端与其他数据包冲�H�而导致丢�?/span>。仔�l�分析上�q�原因后�Q�猛然发玎ͼ�之所以broadcast模式下全部数据包均丢失，是因为source模块中的Packet Interarrival Time讄��为constant�c�d��Q�所有节点均在同一旉��发包�Q�导致所有数据包冲突�Q�而random模式下冲�H�较��的原因是因为数据包不是�q�播形式发送，同一目的端同时接受多个数据包的概率减��了�Q�故只有一定几率下才会冲突�?br>
修正�Ҏ��Q?br>��Packet Interarrival Time讄��为exponenetial�c�d��卛_��Q�错开各节点的发包旉��?br>

�q�风 2010-01-26 10:47 发表评论

OPNET中某些有用的preference讄��

�q�风 — Wed, 24 Jun 2009 08:34:00 GMT

1.��L��q�行仿真时的响声�Q?br>preference -> 搜烦beep的参�?-> ��两��参数值均设成0�?br>
2.ODB调试时窗口不自动关闭�Q?br>preference -> console_exit_pause属性设定�ؓtrue�Q�这样需要输入两�ơEnter后才会关闭�?br>注意�Q�取消debug模式而直接运行时�Q�如果没有将console_exit_pause配置重新改�ؓfalse�Q�可能会出现�q�行完毕后close按钮为灰色的情况�Q�必��L��意�?/span>

3.OPNET与VC联调�Q?br>preference -> bind_shobj_flags的值后面加�?/DEBUG
preference -> comp_flags和comp_flags_cpp后面加上/Zi /Od
config simulation(advanced) -> Envirement files -> include两项�Q�debug和force_compile
�q�行ODB�Q�然后在VC下attach to process�Q�添加op_runsim�q�程�Q�开始联合调试�?br>
4.删除和查看source directory
preference -> mod_dir -> 选择某项删除

�q�风 2009-06-24 16:34 发表评论

"Output stream index (0) is unoccupied"错误处理

�q�风 — Sat, 13 Jun 2009 06:10:00 GMT

出现该问题的原因是：�q�程对应模块的output stream (0)没有定义�Q�可以查看一下节�Ҏ��型中该模块与其他模块之间的数据流向，通常存在两种情况�Q?br>
1.没有0可��出流�Q�此时或者修改进�E�代码中的错误，或者添加模�?可��出流卛_��?br>2.�?可��出流但是依然报错�Q�那么徏议重新布�Uѝ�?br>3.重新布线依然错误�Q�那��找上帝�?#8230;…

�q�风 2009-06-13 14:10 发表评论

"Invalid Memory Acess"错误处理

�q�风 — Sat, 13 Jun 2009 05:54:00 GMT

“无效的内存访�?#8221;——这是一个让人很头疼的问题，错误很隐蔽，调试很麻烦，新手头一�ơ遇到这个问题基本束手无�{�。出现该错误的主要原因在于读取内存越界，特别是��用指针和数组的时候。下面就曄��遇到的情况做一个简单的�ȝ��Q�以防遗忘�?br>
1.在无�U�收发机�Q�wlan_port_rx�Q�中出现"Invalid Memory Acess"错误�Q�提�C?power model"��道阶段有误。利用VC联合调试发现异常出现在power model��道阶段的某数据包指针处�Q�具体原因不明。将原模型的pipeline�E�序wlan_power换成dra_power�Q�错误消失，�E�序正常�q�行�?br>
2.子队列�ؓ�I�，但是没有做判别就使用op_subq_pk_remove��d��包，�׃��子队列�ؓ�I�，所以将��M��C�Q何数据，提示"Invalid Memory Acess"的错误�?br>
3.定义数组大小为MAX_NUM�Q�但是在写入数组时超��数组边界�Q�结果导�?Invalid Memory Acess"的错误�?br>PS�Q�不��是OPNET�~�程�q�是VC下的�~�程�Q�数�l�越界都是一个常见的问题�Q�切��C��定不能出现这�U�错误，不然会痛苦不�?#8230;…

�q�风 2009-06-13 13:54 发表评论

wlan_mac_intf�?Current event is not a stream or access interrupt"错误处理

�q�风 — Wed, 10 Jun 2009 07:40:00 GMT

在ad hoc�|�络仿真中��用src / routing / wlan_mac_intf / wlan_mac层次的节�Ҏ��型，仿真时出现如下错误：

<<< Recoverable Error >>>
* Time:      15:12:26 ÐÇÆÚÈý ÁùÔÂ 10
* Product:   modeler
* Program:   op_runsim (Version 8.1.A PL8 Build 1575)
* System:    Windows NT 5.1 Build 2600
* Package:   process (Bestsink_wlan_mac_intf_test) at module (top.Office Network.ap_1.wlan_mac_intf)
* Function: Bestsink_wlan_mac_intf_test () [idle exit execs]
* Error:     Current event is not a stream or access interrupt.
               T (0), EV (194), MOD (top.Office Network.ap_1.wlan_mac_intf)

分析�Q?br>通过debugger查看得知stream interrupt�q�不在EV(194)处，而是更靠后的事�g�Q�但在仿真到EV(194)处就要读取stream上的包，从而导�?#8220;Current event is not a stream or access interrupt”的错误�?br>
查找原因�Q?br>由T(0)可知错误出现在仿真开始时�Q�此旉��了src模块外routing / wlan_mac_intf / wlan_mac均无数据包发送的动作�Q�所以暂定错误出现的原因是src模块�?.0s时发包，此时wlan_mac_intf模块的初始化��未完毕�Q�从而导致事件序列的混�ؕ�?br>
�U�错�Ҏ��Q?br>��src模块的发包start time定�ؓ10.0s�Q�避免其他模块未初始化完毕的��尬局面。实验证明方法有效�?br>
�ȝ��Q?br>src模块的start time�~�省值就�?0.0s�Q�本人擅做主张改�?.0s�Q�结果出现错误。看来还是小心�ؓ上，不然倒霉的是自己……

�q�风 2009-06-10 15:40 发表评论

�q�风 — Tue, 09 Jun 2009 02:12:00 GMT

因�ؓOPNET各版本之间不能兼容，8.0版本下的�q�程模型�q�移�?.1甚至更高版本后在�~�译时可能��生错误。wlan_mac�q�程模型��是其中一个例子，该进�E�从8.0�q�移�?.1后编译会提示“error�Q�WLAN_AIR_PROPAGATION_TIME未定�?#8221;的错误，此时在进�E�Header Block中添加如下宏�Q?br>

#define WLANC_MSDU_HEADER_SIZE 272 //作用未知
#define WLAN_AIR_PROPAGATION_TIME 0.000001 //定义WLAN_AIR_PROPAGATION_TIME

��d��后重新编译，没有错误�Q�进�E�可以运行�?br>

�q�风 2009-06-09 10:12 发表评论

�q�风 — Wed, 03 Jun 2009 09:01:00 GMT

1.时�g
传播时�g�Q�依赖于传播距离�?br>发送时�Ӟ��W�一个比特发送到最后一个比特传输结束，卛_��长度与发送速率之比�?br>排队时�g�Q�数据包在队列中�{�待旉��?br>
2.�q�程监听
节点内：�l�计�U�或�q�程中断
节点外：�q�程中断

3.事�g�c�d��
自中断：可带ICI信息
��、统计线�Q�可带ICI信息
故障�Q�对节点或链路故障的异步通知�Q�貌似很��用刎ͼ�
接入�Q�access�Q�：�q�程向另一�q�程产生��h��Q�可带ICI信息
�q�程中断�Q�remote�Q�：可带ICI信息
PS�Q��用ICI�Q�在�l�定事�g调度之后应��用op_ici_install�Q�OPC_NIL�Q�进行拆除，以及op_ici_destroy�Q�）�q�行销毁。若一个ICI多次使用�Q�可不用op_ici_destroy�q�行销毁�?br>
4.一些错�?br>process中状态里避免使用return�Q�否则可能出错�?br>如果�q�程模型内部用到队列函数�Q�如op_subq_stat�{�，必须用queue模块才行�?br>避免多个邻近节点同时发包�Q�否则会��D��mac层冲�H�加剧，时�g�q�大�?br>PS�Q�mac层��用CSMA/CA协议�Q�应该有重传机制�Q�但是根据多�ơ试验分析，貌似没有重传一�?#8230;…

5.数据概率分布函数
dist_ptr = op_dist_load�Q�dist_name�Q�dist_arg0�Q�dist_arg1�Q�；
num = op_dist_outcome�Q�dist_ptr�Q�；

6.�l�计数据��?br>op_stat_reg�Q?Packet Size (bits)"�Q�OPC_STAT_INDEX_NONE�Q�OPC_STAT_GLOBAL�Q?br>其中变量1为统计量名，变量3规定全局或局部，�q�回值是句柄stat_handle�?br>op_stat_write�Q�）�Q�写入统计量
op_stat_local_read�Q�instat_index�Q�：instat_index是用数字表示的输入统计变量的索引��|��范围�?�?9
PS�Q�可以一个源对应多个目的模块�Q�可以多个模块同一�l�计量对应同一目的模块�Q�每个统计数据流定义一个信号量�Q�在��的src_stat属性�?br>

�q�风 2009-06-03 17:01 发表评论

license破解��p�|问题

�q�风 — Wed, 03 Jun 2009 08:13:00 GMT

安装OPNET8.1�Q��用license破解工具�Q�结果出现Invalid Memory Access的错误，开始故障查找过�E��?br>
1.�|�线是否断开�Q?br>2.Windows防火墙及其他防火墙��Y件是否关闭？
3.破解license时OPNET是否打开�Q?br>4.是否�W�一�ơ安装OPNET�Q�若不是上一�ơ卸载是否完全？
5.今天人品是不是很差？

以上错误均不成立的情况下�Q�没有其他办法，安安心心重装�pȝ��吧，我日……

�q�风 2009-06-03 16:13 发表评论