Hello My name is Dania, I am new in WiMAX, I am trying to simulate wireless channel for subscriber station (SS), I am using the formula received signal power (RSP): Pr=Pt P0 xR(do/d)α Or in dB Pr(d)[dB] = Pt [dB]+P0 [dB] + 10 α log(d0 /d )+X[dB] + R[dB] Where Pr(d)[dB] is the received power at SS, Pt [dB] transmitted power from BS, P0 [dB] pathloss at reference distance, α pathloss exponent, d distance from BS to SS, d0 is the reference distance, X[dB] shadowing , R[dB] Rayleigh fading received signal envelope. I have questions about shadowing: 1- I generate random numbers for shadowing lognormal numbers with mean 0 and sigma, at each frame I generate the numbers, should these numbers be correlated, I mean at frame 2 for instance, does it should be correlated to the previous value at frame 1, or every frame value should be independent on the pervious ones, even if the SS didn’t move much from its position. 2- I have only one cell consists of many SS and one BS (base station), does the value of shadowing of SS should be correlated to the shadowing values of the neighbor SSs, and how to implement that?. And other questions about Rayleigh fading: 1- I generate Rayleigh distributed signal envelope values along each frame, for instance I generate 10 vales at each frame for Rayleigh signal, and then average all these values to take only one value for that frame and use it in the above formula as R , are my steps correct? 2- In addition to the above formula, I compute the received signal power between SSs, I assumed that the SS are moving or very very slow moving, and I need to compute the Rayleigh signal between them, so, should I compute it in the same way as the signal between BS and SS ????? Please answer me it’s so important. I appreciate your help My regards

# WIRELESS CHANNEL ..........

Started by ●June 13, 2009

Reply by ●June 15, 20092009-06-15

On Jun 13, 12:04 pm, "dania" <dede...@yahoo.com> wrote:> Hello > > My name is Dania, I am new in WiMAX, I am trying to simulate wireless > channel for subscriber station (SS), I am using the formula received signal > power (RSP):Dania, A few general tips that might help you: 1. Please use plain text for your messages. When you want to use letters like alpha, you may use LaTeX notation such as \alpha or just use the text representation "alpha". Both those work better than using any special characters which can't be read by text-based newsgroup readers. 2. Please have a look at Usenet posting guidelines such as: http://www.faqs.org/faqs/usenet/primer/part1/ especially guidelines on repeat posting.> > Pr=Pt P0 xR(do/d)α > Or in dB > > Pr(d)[dB] = Pt [dB]+P0 [dB] + 10 α log(d0 /d )+X[dB] + R[dB] > > Where Pr(d)[dB] is the received power at SS, Pt [dB] transmitted power > from BS, P0 [dB] pathloss at reference distance, α pathloss exponent, d > distance from BS to SS, d0 is the reference distance, X[dB] shadowing , > R[dB] Rayleigh fading received signal envelope. > I have questions about shadowing: > > 1- I generate random numbers for shadowing lognormal numbers with mean 0 > and sigma, at each frame I generate the numbers, should these numbers be > correlated, I mean at frame 2 for instance, does it should be correlated to > the previous value at frame 1, or every frame value should be independent > on the pervious ones, even if the SS didn’t move much from its position.All your questions relate to what model to use for the lognormal fading and the Rayleigh fading. The general answer is, it depends. You need to either make assumptions or gather from the specifications data on various traffic models for WiMAX, specifically what speeds the SSs are moving at, what the relative distances are and what kind of fading models to use. I would recommend first reading a text on WiMax physical layer modeling which should help with many of your questions.> 2- I have only one cell consists of many SS and one BS (base station), > does the value of shadowing of SS should be correlated to the shadowing > values of the neighbor SSs, and how to implement that? > > And other questions about Rayleigh fading: > > 1- I generate Rayleigh distributed signal envelope values along each > frame, for instance I generate 10 vales at each frame for Rayleigh signal, > and then average all these values to take only one value for that frame and > use it in the above formula as R , are my steps correct? > 2- In addition to the above formula, I compute the received signal power > between SSs, I assumed that the SS are moving or very very slow moving, and > I need to compute the Rayleigh signal between them, so, should I compute it > in the same way as the signal between BS and SS ????? > Please answer me it’s so important. > I appreciate your help > My regards