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Re: Beamforming and MRC basics

Started by Zeph80 March 23, 2007
I have a very basic question with regards to beam-forming or MRC. When I
apply complex weigths for example while doing co-phasing for MRC, does
this phase rotate my constellation. Everywhere I read , I never see a
beamforming effect on the demodulation. Given Im using a PSK kind of
modulation,don't these complex weights affect my constellations.After all
isnt pSk modulation some form of Sin(wct + Theta(t)).
Or should I look at MRC co-phasing, as just aligining multipath
componenets, i.e complex weigth just results in aligining modulated
symbol1 of path1 to modulated symbol1 of path2, which would otherwise be
not aligned.
And how would I explain beamforming, not changing the constellation.

Zeph80 wrote:
> I have a very basic question with regards to beam-forming or MRC. When I > apply complex weigths for example while doing co-phasing for MRC, does > this phase rotate my constellation. Everywhere I read , I never see a > beamforming effect on the demodulation. Given Im using a PSK kind of > modulation,don't these complex weights affect my constellations.After all > isnt pSk modulation some form of Sin(wct + Theta(t)). > Or should I look at MRC co-phasing, as just aligining multipath > componenets, i.e complex weigth just results in aligining modulated > symbol1 of path1 to modulated symbol1 of path2, which would otherwise be > not aligned. > And how would I explain beamforming, not changing the constellation.
The constellation is a phenomenon of modulation rate. Beamforming is done by adjusting the phase of the several carriers. They are unrelated phenomena. Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
>Zeph80 wrote: >> I have a very basic question with regards to beam-forming or MRC. When
I
>> apply complex weigths for example while doing co-phasing for MRC, does >> this phase rotate my constellation. Everywhere I read , I never see a >> beamforming effect on the demodulation. Given Im using a PSK kind of >> modulation,don't these complex weights affect my constellations.After
all
>> isnt pSk modulation some form of Sin(wct + Theta(t)). >> Or should I look at MRC co-phasing, as just aligining multipath >> componenets, i.e complex weigth just results in aligining modulated >> symbol1 of path1 to modulated symbol1 of path2, which would otherwise
be
>> not aligned. >> And how would I explain beamforming, not changing the constellation. > >The constellation is a phenomenon of modulation rate. Beamforming is >done by adjusting the phase of the several carriers. They are unrelated >phenomena. > >Jerry >-- >Engineering is the art of making what you want from things you can get. >¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Im not sure I understand that well. The implementation of the constellation is still done by phase varying of the carrier.
If it properly done and you convert back to the time-domain after the 
beamforming operation then you shouldn't dee any effect from the beamforming.

In article <vO2dnS98G4RegJnbnZ2dnUVZ_sudnZ2d@giganews.com>, "Zeph80" 
<surabhi_talwar@hotmail.com> wrote:
>>Zeph80 wrote: >>> I have a very basic question with regards to beam-forming or MRC. When >I >>> apply complex weigths for example while doing co-phasing for MRC, does >>> this phase rotate my constellation. Everywhere I read , I never see a >>> beamforming effect on the demodulation. Given Im using a PSK kind of >>> modulation,don't these complex weights affect my constellations.After >all >>> isnt pSk modulation some form of Sin(wct + Theta(t)). >>> Or should I look at MRC co-phasing, as just aligining multipath >>> componenets, i.e complex weigth just results in aligining modulated >>> symbol1 of path1 to modulated symbol1 of path2, which would otherwise >be >>> not aligned. >>> And how would I explain beamforming, not changing the constellation. >> >>The constellation is a phenomenon of modulation rate. Beamforming is >>done by adjusting the phase of the several carriers. They are unrelated >>phenomena. >> >>Jerry >>-- >>Engineering is the art of making what you want from things you can get. >>&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr; >&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr; > >Im not sure I understand that well. The implementation of the >constellation is still done by phase varying of the carrier.
                                      Person
                                            ...
                                             . ..
                                              .  ..
                                               .  . .
                                                .  .  .
                                                 .  .   .
                                                 |_ |__|_ Antennas

based on phase signature of person's location.. diferent phase
weights..applied..to modulated signals..make signal converge..at same
point at same time..allowing..for..coherent combining..this is what i
read in one of the paper.
expertsin this group..please confirm and correct if i am wrong..

regards
particlereddy






On Mar 25, 2:09 am, John_W_Her...@yahoo.com (John Herman) wrote:
> If it properly done and you convert back to the time-domain after the > beamforming operation then you shouldn't dee any effect from the beamform=
ing.
> > In article <vO2dnS98G4RegJnbnZ2dnUVZ_sudn...@giganews.com>, "Zeph80" > > <surabhi_tal...@hotmail.com> wrote: > >>Zeph80 wrote: > >>> I have a very basic question with regards to beam-forming or MRC. When > >I > >>> apply complex weigths for example while doing co-phasing for MRC, does > >>> this phase rotate my constellation. Everywhere I read , I never see a > >>> beamforming effect on the demodulation. Given Im using a PSK kind of > >>> modulation,don't these complex weights affect my constellations.After > >all > >>> isnt pSk modulation some form of Sin(wct + Theta(t)). > >>> Or should I look at MRC co-phasing, as just aligining multipath > >>> componenets, i.e complex weigth just results in aligining modulated > >>> symbol1 of path1 to modulated symbol1 of path2, which would otherwise > >be > >>> not aligned. > >>> And how would I explain beamforming, not changing the constellation. > > >>The constellation is a phenomenon of modulation rate. Beamforming is > >>done by adjusting the phase of the several carriers. They are unrelated > >>phenomena. > > >>Jerry > >>-- > >>Engineering is the art of making what you want from things you can get. > >>=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=
=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF
> >=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=
=AF=AF=AF=AF=AF=AF=AF
> > >Im not sure I understand that well. The implementation of the > >constellation is still done by phase varying of the carrier.
On 25 Mar, 04:43, "PARTICLEREDDY (STRAYDOG)" <particlere...@gmail.com>
wrote:
> Person > ... > . .. > . .. > . . . > . . . > . . . > |_ |__|_ Antennas > > based on phase signature of person's location.. diferent phase > weights..applied..to modulated signals..make signal converge..at same > point at same time..allowing..for..coherent combining..this is what i > read in one of the paper.
Which paper was this?
> expertsin this group..please confirm and correct if i am wrong..
This works fine in theory and in computer simulations. In real life, however, you need to account for multiple reflections from the ground, if you are using this system outdoors, or from walls, floors and ceilings if inside. Not to mention objects, like furniture, carpets; anything that affect the reflective properties of the sound. Rune
"""""""""" This works fine in theory and in computer simulations.
In real life, however, you need to account for multiple
reflections from the ground, if you are using this system
outdoors, or from walls, floors and ceilings if inside.
Not to mention objects, like furniture, carpets; anything
that affect the reflective properties of the sound.
""""""""""""""'''''''

no i dont think so,, when your ANTENNAS are focussing the beam at a
particular point in such a way that every signal from each antenna
falls in coherence (Assuming 1 antenna at the Subscriber station).and
also..you do ultra narrow beamforming at each antenna to focus in
particular direction according to phase signature..then i dont
think..multiple reflection is any affect at all particularly on
beamforming..regarding paper yes..will track and post in my next
post..

regards
particlereddy


On Mar 25, 2:29 pm, "Rune Allnor" <all...@tele.ntnu.no> wrote:
> On 25 Mar, 04:43, "PARTICLEREDDY (STRAYDOG)" <particlere...@gmail.com> > wrote: > > > Person > > ... > > . .. > > . .. > > . . . > > . . . > > . . . > > |_ |__|_ Antennas > > > based on phase signature of person's location.. diferent phase > > weights..applied..to modulated signals..make signal converge..at same > > point at same time..allowing..for..coherent combining..this is what i > > read in one of the paper. > > Which paper was this? > > > expertsin this group..please confirm and correct if i am wrong.. > > This works fine in theory and in computer simulations. > In real life, however, you need to account for multiple > reflections from the ground, if you are using this system > outdoors, or from walls, floors and ceilings if inside. > Not to mention objects, like furniture, carpets; anything > that affect the reflective properties of the sound. > > Rune