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I am making a simulation using 5G-toolbox in Matlab. IN 5Gtoolbox we have two kind of channels, CDLChannel and TDLChannel. Now, CDL means Clusteresd Delay Line, and TDL means Tapped Delay Lines. But what does it actually mean?

Also, I want to simulate an indoor environment with high shadowing and penetration losses, plus an outdoor environment? Which model suits best in either case?

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    $\begingroup$ Read the 3GPP specification. Rule 1: the TDL models are the simpler; use them if you don't need to simulate MIMO. Rule 2: the parameters are relative and can be scaled to match your desired setup. For an indoor environment, use the NLoS models. You can try TDL-A, TDL-B, and TDL-C. $\endgroup$
    – AlexTP
    Commented Oct 15, 2021 at 21:08
  • $\begingroup$ Thanks, if you can put it in answer, I can mark it as a solution. $\endgroup$
    – SJa
    Commented Oct 18, 2021 at 14:49
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    $\begingroup$ They are all well defined in the specification. In short, TDL is the model of taps with different delays (therefore the name Tapped Delay Line); each tap is modeled as a random variable. CDL is a generalization that taps are replaced by clusters for the interest of spatial characteristics. Everything else can be found in the specification. My answer, if any, would be just the copy paste of the spec. $\endgroup$
    – AlexTP
    Commented Oct 18, 2021 at 18:09
  • $\begingroup$ I'm wondering how to generate a wireless channel also. As I could see in the TDL, CDL table, they have fixed Average powers (which are the mean from which we can generate our random power). But what I'm wondering is that, do these tables already include the path loss? how could I modify it for nearer users and further users? how could I apply the path loss to that? If you know the details about it, please let me know ^^ thank you $\endgroup$
    – Hiếu Hoàng
    Commented Jun 28 at 18:23

1 Answer 1

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I want to share my understanding here for my future self as well as for any other user who happens to have the same question.

  1. TDL Model is preferred usually for simplified evaluations (e.g. non-MIMO scenarios). (See Section 7.7.2 in T38.900)

1a. According to specs, three TDL models, namely TDL-A, TDL-B and TDL-C, are constructed to represent three different channel profiles for NLOS while TDL-D and TDL-E are constructed for LOS, the parameters of which can be found respectively in Table 7.7.2-1, Table 7.7.2-2 , Table 7.7.2-3, Table 7.7.2-4 and Table 7.7.2-5.

  1. Given point 1, I believe CDL is more appropriate for MIMO type scenarios (which are the more prevalent scenarios in modern cellular link-level simulations).

I will keep on editing it as I better my understanding.

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