Is the power delay profile dependent on the carrier frequency? I have read in many books that the delay spread for outdoor environment is in the order of 1 us. But that is for carrier frequency of around 900 Mhz. (cellular communication). I need the power delay profile for FM transmission (88 – 108 Mhz. range). Is the delay spread the same ? Thanks.
Power delay profile doubt
Started by ●June 28, 2009
Reply by ●June 28, 20092009-06-28
>Is the power delay profile dependent on the carrier frequency? > >I have read in many books that the delay spread for outdoor environmentis>in the order of 1 us. But that is for carrier frequency of around 900Mhz.>(cellular communication). I need the power delay profile for FM >transmission (88 – 108 Mhz. range). Is the delay spread the same ? > >Thanks. > > > >no it does not depend on carrier freq. u should check some standards like WiMax and all...they generally give PDP
Reply by ●June 28, 20092009-06-28
shekar1989 wrote:> Is the power delay profile dependent on the carrier frequency?The power delay profile depends on the propagation conditions. The conditions depend on the frequency band (in the large scale), the antennae position, the distance and the typical obstacles and reflectors.> I have read in many books that the delay spread for outdoor environment is > in the order of 1 us. But that is for carrier frequency of around 900 Mhz. > (cellular communication).That's about right for the quazi optical propagation, near zone and the hand held terminals.> I need the power delay profile for FM > transmission (88 ��� 108 Mhz. range).You need the delay profile to do what?> Is the delay spread the same ?It is quite different from 900MHz cellular. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●June 28, 20092009-06-28
On 6/28/2009 8:57 AM, shekar1989 wrote:> Is the power delay profile dependent on the carrier frequency? > > I have read in many books that the delay spread for outdoor environment is > in the order of 1 us. But that is for carrier frequency of around 900 Mhz. > (cellular communication). I need the power delay profile for FM > transmission (88 – 108 Mhz. range). Is the delay spread the same ? > > Thanks.The power delay profile typically depends more on the transmit power, types of antennas used, and terrain type than on the carrier frequency, although that does matter, too.
Reply by ●June 29, 20092009-06-29
> > >shekar1989 wrote: > >> Is the power delay profile dependent on the carrier frequency? > >The power delay profile depends on the propagation conditions. The=20 >conditions depend on the frequency band (in the large scale), the=20 >antennae position, the distance and the typical obstacles andreflectors.=> > >> I have read in many books that the delay spread for outdoorenvironment=> is >> in the order of 1 us. But that is for carrier frequency of around 900M=>hz. >> (cellular communication).=20 > >That's about right for the quazi optical propagation, near zone andthe=20>hand held terminals. > >> I need the power delay profile for FM >> transmission (88 =F2=C0=D3 108 Mhz. range). > >You need the delay profile to do what? > >> Is the delay spread the same ? > >It is quite different from 900MHz cellular. > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >Thanks for the reply,Now I understand what the power delay profile depends on. It is independent of carrier frequency, since it is only the measure of the channel characteristics and the surrounding environment. I wanted to study the effect of fading for FM transmission (whether it is flat and slow fading ... and so on ). Nearly all websites mention for 802.11 or cellular but not for FM, (digital). Can anyone provide a link/paper which deals with fading for Digital FM transmission (88-108 Mhz range) ? Thanks.
Reply by ●June 29, 20092009-06-29
On Jun 29, 11:23�am, "shekar1989" <yogicyog...@gmail.com> wrote:> >shekar1989 wrote: > > >> Is the power delay profile dependent on the carrier frequency? > > >The power delay profile depends on the propagation conditions. The=20 > >conditions depend on the frequency band (in the large scale), the=20 > >antennae position, the distance and the typical obstacles and > reflectors.= > > >> I have read in many books that the delay spread for outdoor > environment= > > is > >> in the order of 1 us. But that is for carrier frequency of around 900 > M= > >hz. > >> (cellular communication).=20 > > >That's about right for the quazi optical propagation, near zone and > the=20 > >hand held terminals. > > >> I need the power delay profile for FM > >> transmission (88 =F2=C0=D3 108 Mhz. range). > > >You need the delay profile to do what? > > >> Is the delay spread the same ? > > >It is quite different from 900MHz cellular. > > >Vladimir Vassilevsky > >DSP and Mixed Signal Design Consultant > >http://www.abvolt.com > > >Thanks for the reply, > > �Now I understand what the power delay profile depends on. > �It is independent of carrier frequency, since it is only the measure of � > the channel characteristics and the surrounding environment. I wanted to > study the effect of fading for FM transmission (whether it is flat and slow > fading ... and so on ). Nearly all websites mention for 802.11 or cellular > but not for FM, (digital). Can anyone provide a link/paper which deals with > fading for Digital FM transmission (88-108 Mhz range) ? � > Thanks.You are too quick to dismiss carrier frequency, see title={A propagation measurement-based analysis of frequency hopping systems on VHF mobile fading channels}, author={Pugh, J.A. and Vigneron, P.J. and Bultitude, R.J.C. }, booktitle={IEEE Canadian Conference on Electrical and Computer Engineering}, year={2005}, month={May.}, title={Propagation models for mobile terrestrial VHF communications}, author={Vigneron, P.J. and Pugh, J.A.}, booktitle={Military Communications Conference, 2008. MILCOM 2008. IEEE}, year={2008}, month={Nov.},
Reply by ●June 29, 20092009-06-29
shekar1989 wrote:>> >> shekar1989 wrote: >> >>> Is the power delay profile dependent on the carrier frequency? >> The power delay profile depends on the propagation conditions. The=20 >> conditions depend on the frequency band (in the large scale), the=20 >> antennae position, the distance and the typical obstacles and > reflectors.= >> >>> I have read in many books that the delay spread for outdoor > environment= >> is >>> in the order of 1 us. But that is for carrier frequency of around 900 > M= >> hz. >>> (cellular communication).=20 >> That's about right for the quazi optical propagation, near zone and > the=20 >> hand held terminals. >> >>> I need the power delay profile for FM >>> transmission (88 =F2=C0=D3 108 Mhz. range). >> You need the delay profile to do what? >> >>> Is the delay spread the same ? >> It is quite different from 900MHz cellular. >> >> >> Vladimir Vassilevsky >> DSP and Mixed Signal Design Consultant >> http://www.abvolt.com >> >> Thanks for the reply, > Now I understand what the power delay profile depends on. > It is independent of carrier frequency, since it is only the measure of > the channel characteristics and the surrounding environment.Do you suppose that the channel characteristics are independent of carrier frequency? The world is rarely that simple.> I wanted to > study the effect of fading for FM transmission (whether it is flat and slow > fading ... and so on ). Nearly all websites mention for 802.11 or cellular > but not for FM, (digital). Can anyone provide a link/paper which deals with > fading for Digital FM transmission (88-108 Mhz range) ? > Thanks.Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 30, 20092009-06-30
>On Jun 29, 11:23=A0am, "shekar1989" <yogicyog...@gmail.com> wrote: >> >shekar1989 wrote: >> >> >> Is the power delay profile dependent on the carrier frequency? >> >> >The power delay profile depends on the propagation conditions.The=3D20>> >conditions depend on the frequency band (in the large scale),the=3D20>> >antennae position, the distance and the typical obstacles and >> reflectors.=3D >> >> >> I have read in many books that the delay spread for outdoor >> environment=3D >> > is >> >> in the order of 1 us. But that is for carrier frequency of around900>> M=3D >> >hz. >> >> (cellular communication).=3D20 >> >> >That's about right for the quazi optical propagation, near zone and >> the=3D20 >> >hand held terminals. >> >> >> I need the power delay profile for FM >> >> transmission (88 =3DF2=3DC0=3DD3 108 Mhz. range). >> >> >You need the delay profile to do what? >> >> >> Is the delay spread the same ? >> >> >It is quite different from 900MHz cellular. >> >> >Vladimir Vassilevsky >> >DSP and Mixed Signal Design Consultant >> >http://www.abvolt.com >> >> >Thanks for the reply, >> >> =A0Now I understand what the power delay profile depends on. >> =A0It is independent of carrier frequency, since it is only the measureo=>f =A0 >> the channel characteristics and the surrounding environment. I wantedto>> study the effect of fading for FM transmission (whether it is flat andsl=>ow >> fading ... and so on ). Nearly all websites mention for 802.11 orcellula=>r >> but not for FM, (digital). Can anyone provide a link/paper which dealswi=>th >> fading for Digital FM transmission (88-108 Mhz range) ? =A0 >> Thanks. > >You are too quick to dismiss carrier frequency, see > >title=3D{A propagation measurement-based analysis of frequency hopping >systems on VHF mobile fading channels}, >author=3D{Pugh, J.A. and Vigneron, P.J. and Bultitude, R.J.C. }, >booktitle=3D{IEEE Canadian Conference on Electrical and Computer >Engineering}, >year=3D{2005}, >month=3D{May.}, > >title=3D{Propagation models for mobile terrestrial VHF communications}, >author=3D{Vigneron, P.J. and Pugh, J.A.}, >booktitle=3D{Military Communications Conference, 2008. MILCOM 2008. >IEEE}, >year=3D{2008}, >month=3D{Nov.}, > > > >=================================================================== PDP is the distribution of the multipath power over time, so it can't depend on frequency. It must be said however, that it may include frequency only for better analysis of the channel, as suggested by Vladimir and the papers he put to support his argument, but we only consider the effect of fast fading due to doppler spread caused by doppler shift which does depend on frequency (I haven't gone through the papers but I can think of why they included frequency) Again we'd just be forcing the matter to include frequency, usually we use a worst case doppler shift is chosen along with the PDP Student from Pakistan
Reply by ●June 30, 20092009-06-30
>On Jun 29, 11:23=A0am, "shekar1989" <yogicyog...@gmail.com> wrote: >> >shekar1989 wrote: >> >> >> Is the power delay profile dependent on the carrier frequency? >> >> >The power delay profile depends on the propagation conditions.The=3D20>> >conditions depend on the frequency band (in the large scale),the=3D20>> >antennae position, the distance and the typical obstacles and >> reflectors.=3D >> >> >> I have read in many books that the delay spread for outdoor >> environment=3D >> > is >> >> in the order of 1 us. But that is for carrier frequency of around900>> M=3D >> >hz. >> >> (cellular communication).=3D20 >> >> >That's about right for the quazi optical propagation, near zone and >> the=3D20 >> >hand held terminals. >> >> >> I need the power delay profile for FM >> >> transmission (88 =3DF2=3DC0=3DD3 108 Mhz. range). >> >> >You need the delay profile to do what? >> >> >> Is the delay spread the same ? >> >> >It is quite different from 900MHz cellular. >> >> >Vladimir Vassilevsky >> >DSP and Mixed Signal Design Consultant >> >http://www.abvolt.com >> >> >Thanks for the reply, >> >> =A0Now I understand what the power delay profile depends on. >> =A0It is independent of carrier frequency, since it is only the measureo=>f =A0 >> the channel characteristics and the surrounding environment. I wantedto>> study the effect of fading for FM transmission (whether it is flat andsl=>ow >> fading ... and so on ). Nearly all websites mention for 802.11 orcellula=>r >> but not for FM, (digital). Can anyone provide a link/paper which dealswi=>th >> fading for Digital FM transmission (88-108 Mhz range) ? =A0 >> Thanks. > >You are too quick to dismiss carrier frequency, see > >title=3D{A propagation measurement-based analysis of frequency hopping >systems on VHF mobile fading channels}, >author=3D{Pugh, J.A. and Vigneron, P.J. and Bultitude, R.J.C. }, >booktitle=3D{IEEE Canadian Conference on Electrical and Computer >Engineering}, >year=3D{2005}, >month=3D{May.}, > >title=3D{Propagation models for mobile terrestrial VHF communications}, >author=3D{Vigneron, P.J. and Pugh, J.A.}, >booktitle=3D{Military Communications Conference, 2008. MILCOM 2008. >IEEE}, >year=3D{2008}, >month=3D{Nov.}, > > > >=================================================================== PDP is the distribution of the multipath power over time, so it can't depend on frequency. It must be said however, that it may include frequency only for better analysis of the channel, as suggested by Vladimir and the papers he put to support his argument, but we only consider the effect of fast fading due to doppler spread caused by doppler shift which does depend on frequency (I haven't gone through the papers but I can think of why they included frequency) Again we'd just be forcing the matter to include frequency, usually we use a worst case doppler shift is chosen along with the PDP Student from Pakistan
Reply by ●June 30, 20092009-06-30
commengr wrote:> PDP is the distribution of the multipath power over time, so it can't > depend on frequency.Multipath effect depends from the frequency in the large scale, as it is determined by the wave length/obstacle size. The propagation is different too; the 900MHz is ~3 octaves higher then FM band, so the PDP is very different. The deployment conditions of the FM broadcast are also very different from the personal communication.> It must be said however, that it may include frequency only for better > analysis of the channel, as suggested by Vladimir and the papers he put to > support his argument, but we only consider the effect of fast fading due to > doppler spread caused by doppler shift which does depend on frequency (I > haven't gone through the papers but I can think of why they included > frequency) > > Again we'd just be forcing the matter to include frequency, usually we use > a worst case doppler shift is chosen along with the PDPEh? Too many smart scientific words; understood nothing. Keep it simple. BTW, it is fun to simulate the FM quality in the presense of multipath and interferrence; the effects are very audible. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
