[ns] Help needed for ns2HCCA patch
ritwikmitra at yahoo.com
Sun Apr 16 10:14:33 PDT 2006
I am working on a project on 802.11E schedulers. I am trying to implement ARROW and SETT-EDD schedulers with some minor modifications, using the ns2HCCA patch for NS-2.27.
However, I am facing the following problems:
1. Where (in the code) does a CAP start mechanism take place. There is a startCAP(void) function in mac-802_11e.cc file, but it is called twice. Once, when we specify start-hcca in the TCL script and second time when we pass the TSPEC parameters in the TCL script.
Is this function called only when the QAP starts a CAP?
2. How does the patch ensure that the TXOP list that is created is being followed fully. Consider the offline TXOP list that is created. Suppose it contains the TXOP times for the stations 1,2,5,6. How does the patch ensure that first only station 1 will access the channel, and then stations 2, 5, 6 ... and so on. How is this being ensured?
3. How do the stations get access to the channel i.e. how does the channel access switch mechanism take place. E.g. Suppose at time t station 1 is accessing the channel. After time t+t1 , i want station 2 to access the channel. How can i do that?
I would be really grateful if anyone could explain me the working of the patch w.r.t the questions mentioned above. Also, any suggestion as to how to go about implementing the ARROW scheduler would be welcome.
Thanks in advance.
M.Sc. Computer Science
Department of Computer Science,
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