在运行期间更改一组特定车辆的传输信号强度 [英] Change the transmission signal strength for a specific set of vehicles during the run-time
问题描述
我开始(大约一周后)在 omnet++ (5.0) 下使用静脉 (4.4).
我目前的任务是让车辆根据特定环境调整其传输范围.我确实阅读了很多这样的问题(以及其他主题/论坛):
I started (since about one week) using veins (4.4) under omnet++ (5.0).
My current task is to let vehicles adjust their transmission range according to a specific context. I did read a lot of asked questions like these ones (and in other topics/forums):
我的问题:
如何-真正-改变一些节点的传输范围?
从上面的链接中，我知道术语传输范围"在技术上与定义接收概率的接收功率、噪声、灵敏度阈值等有关.
How to -really- change the transmission range of just some nodes?
From the links above, I knew that the term "transmission range", technically, is related to the received power, noise,sensitivity threshold, etc. which defines the probability of reception.
由于我对静脉(以及 omnet++ 也是如此)不熟悉，所以我做了很少的测试并得出以下结论:
Since I am new to veins (and omnet++ as well), I did few tests and I concluded the following:
TraCIMobility"模块可以调整节点的ID、速度等参数(每辆车都有一个实例)
"TraCIMobility" module can adjust the nodes' parameters (for each vehicle, there is an instance) such as the ID, speed, etc.
我也可以实例化Mac1609_4"(对于每辆车)并更改其一些参数，例如txPower"在模拟运行时但它对实际通信范围没有影响.
I could, also, instantiate the "Mac1609_4" (for each vehicle) and changed some of its parameters like the "txPower" during simulation run-time but it had no effect on the real communication range.
我无法实例化(因为它是全局的)连接管理器"唯一负责(并覆盖)有效通信范围的模块.这个模块可以在.ini"文件中配置.文件，但我想要不同的传输功率，最重要的是可以在运行时更改".
I could not instantiate (because it was global) the "connection manager" module which was the only responsible of (and does override) the effective communication range. this module can be configured in the ".ini" file but I want different transmission powers and most importantly "can be changed during run-time".
计算传输范围的公式在附上的链接里，我知道了，但它必须是一种在其中一个层中定义或更改这些参数的方法(即使它在phy层中，即，类似于附加的信号强度...)
The formula to calculate the transmission range is in the attached links, I got it, but it must be a way to define or change these parameters in one of the layers (even if it is in the phy layer, i.e., something like the attached signal strength...)
再说一次，也许我说的有一些错误的想法，我只是想知道什么/如何改变这个传输范围.
Again, maybe there is some wrong ideas in what I have said, I just want to know what/how to change this transmission range.
最好的问候，
推荐答案
增加mac1609_4.txPower 参数，让节点以更大的功率发送(因此，信号可以在更远的地方解码).但是请注意，(对于 Veins 4.4)您还需要增加 connectionManager.pMax 然后，因为该值用于确定接收模拟模块将被告知的最大距离(远离发送模拟模块)持续传输.任何较远的接收模拟模块都不会受到传输的影响(从它是解码候选的意义上说，但也从它有助于干扰的意义上说).
You were right to increase the mac1609_4.txPower parameter to have a node send with more power (hence, the signal being decodable further away). Note, however, that (for Veins 4.4) you will also need to increase connectionManager.pMax then, as this value is used to determine the maximum distance (away from a transmitting simulation module) that a receiving simulation module will be informed about an ongoing transmission. Any receiving simulation module further away will not be influenced by the transmission (in the sense of it being a candidate for decoding, but also in the sense of it contributing to interference).
还要注意，在(否则)完全空闲的信道上的传输将比在典型负载的信道上传输的距离要远得多.如果您想获得传输到达多远的良好测量，让一些节点产生干扰(通过传输自己的广播)，然后查看帧传输率 (FDR) 如何随着发送方和接收方之间的距离增加而下降.
Also note that transmissions on an (otherwise) perfectly idle channel will reach much further than transmissions on a typically-loaded channel. If you want to obtain a good measurement of how far a transmission reaches, have some nodes create interference (by transmitting broadcasts of their own), then look at how the Frame Delivery Rate (FDR) drops as distance between sender and receiver increases.
最后，请注意 1) 本底噪声和 2) 接收器的模拟模块尝试解码帧所需的最小功率电平都需要针对您要模拟的 WLAN 卡进行校准.Veins 4.4 教程示例中选择的值对于演示 Veins 的概念非常有用，而 Veins 最新版本的值 更接近您对一些最近的现场测试中使用的典型"WLAN 卡的期望.请参阅论文 Bastian Bloessl 和 Aisling O'Driscoll，A Case for Good Defaults: Pitfalls inVANET 物理层模拟"，2019 年 IFIP 无线日会议论文集，英国曼彻斯特，2019 年 4 月，对这些参数进行了更详细的讨论.
Finally, note that both 1) the noise floor and 2) the minimum power level necessary for the simulation module of a receiver to attempt decoding a frame need to be calibrated to the WLAN card you want to simulate. The values chosen in the Veins 4.4 tutorial example are very useful for demonstrating the concepts of Veins, whereas the values of more recent versions of Veins come closer to what you would expect from a "typical" WLAN card used in some of the more recent field tests. See the paper Bastian Bloessl and Aisling O'Driscoll, "A Case for Good Defaults: Pitfalls in VANET Physical Layer Simulations," Proceedings of IFIP Wireless Days Conference 2019, Manchester, UK, April 2019 for a more detailed discussion of these parameters.
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