normally, why do we use differential BPSK spread by Barker sequence as preambles? what do we need to take into account when designing preambles? thanks a lot
question on preamble
Started by ●August 1, 2006
Reply by ●August 1, 20062006-08-01
philgo@gmail.com wrote:> normally, why do we use differential BPSK spread by Barker sequence as > preambles? > what do we need to take into account when designing preambles? > thanks a lotFor the benefit of those who aren't long-distance mind readers, preamble to what? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●August 1, 20062006-08-01
philgo@gmail.com wrote:> normally, why do we use differential BPSK spread by Barker sequence as > preambles? > what do we need to take into account when designing preambles? > thanks a lothomework?
Reply by ●August 1, 20062006-08-01
Jerry Avins wrote:> philgo@gmail.com wrote: > > normally, why do we use differential BPSK spread by Barker sequence as > > preambles? > > what do we need to take into account when designing preambles? > > thanks a lot > > For the benefit of those who aren't long-distance mind readers, preamble > to what? > > 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=AFsorry for not being clear. I am referring to preamble to the data. Normally we need to use preamble to do synchronization and channel estimation job.
Reply by ●August 2, 20062006-08-02
BPSK is 'generally' used for the pre-amble as it is more tolerant to channel impairments. The preamble sequence should have good auto correlation and cross correlation properties to have higher probabity of correct detection. One good pointer on barker sequnces is : S=2E Lee and J. Ahn, "Acquisition performance improvement by Barker sequence repetition in a preamble for DS-CDMA systems with symbol length spreading codes," IEEE Transactions on Vehicular Technology, vol. 52, issue 1, pp. 127-131. January 2003. philgo wrote:> Jerry Avins wrote: > > philgo@gmail.com wrote: > > > normally, why do we use differential BPSK spread by Barker sequence as > > > preambles? > > > what do we need to take into account when designing preambles? > > > thanks a lot > > > > For the benefit of those who aren't long-distance mind readers, preamble > > to what? > > > > 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 > > sorry for not being clear. > > I am referring to preamble to the data. Normally we need to use > preamble to do synchronization and channel estimation job.
Reply by ●August 2, 20062006-08-02
philgo wrote:> Jerry Avins wrote: >> philgo@gmail.com wrote: >>> normally, why do we use differential BPSK spread by Barker sequence as >>> preambles? >>> what do we need to take into account when designing preambles? >>> thanks a lot >> For the benefit of those who aren't long-distance mind readers, preamble >> to what? >> >> Jerry >> -- >> Engineering is the art of making what you want from things you can get. >> �������������� > > sorry for not being clear. > > I am referring to preamble to the data. Normally we need to use > preamble to do synchronization and channel estimation job.Now I have a lot more information, but still not enough go guess. You don't tell what kind of channel. The optimum preamble depends on that. For example, baseband SCADA systems use preambles too. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●August 2, 20062006-08-02
I am so sorry again. This was my first post. I will learn to ask good questions. :) How about AWGN channel and fading channel respectively, Jerry? You have any comment? Thanks a lot. Jerry Avins wrote:> philgo wrote: > > Jerry Avins wrote: > >> philgo@gmail.com wrote: > >>> normally, why do we use differential BPSK spread by Barker sequence as > >>> preambles? > >>> what do we need to take into account when designing preambles? > >>> thanks a lot > >> For the benefit of those who aren't long-distance mind readers, preamb=le> >> to what? > >> > >> 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 > > > > sorry for not being clear. > > > > I am referring to preamble to the data. Normally we need to use > > preamble to do synchronization and channel estimation job. > > Now I have a lot more information, but still not enough go guess. You > don't tell what kind of channel. The optimum preamble depends on that. > For example, baseband SCADA systems use preambles too. > > 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=AF
Reply by ●August 2, 20062006-08-02
philgo wrote:> I am so sorry again. This was my first post. I will learn to ask good > questions. :) > > How about AWGN channel and fading channel respectively, Jerry? You have > any comment? Thanks a lot.I'll leave that to people here with experience with the subject. (You might add the modulation type to your description.) A "FAQ" that some people here wrote and that I host may be worth your time to read. At http://users.rcn.com/jyavins/, click on "How to ask ..." Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●August 2, 20062006-08-02
thank you for the faq. Jerry Avins wrote:> philgo wrote: > > I am so sorry again. This was my first post. I will learn to ask good > > questions. :) > > > > How about AWGN channel and fading channel respectively, Jerry? You have > > any comment? Thanks a lot. > > I'll leave that to people here with experience with the subject. (You > might add the modulation type to your description.) A "FAQ" that some > people here wrote and that I host may be worth your time to read. At > http://users.rcn.com/jyavins/, click on "How to ask ..." > > 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=AF
Reply by ●August 2, 20062006-08-02
thank you Kiran wrote:> BPSK is 'generally' used for the pre-amble as it is more tolerant to > channel impairments. > The preamble sequence should have good auto correlation and cross > correlation properties to have higher probabity of correct detection. > One good pointer on barker sequnces is : > S. Lee and J. Ahn, "Acquisition performance > improvement by Barker sequence repetition in a > preamble for DS-CDMA systems with symbol length > spreading codes," IEEE Transactions on Vehicular > Technology, vol. 52, issue 1, pp. 127-131. January > 2003. > philgo wrote: > > Jerry Avins wrote: > > > philgo@gmail.com wrote: > > > > normally, why do we use differential BPSK spread by Barker sequence=as> > > > preambles? > > > > what do we need to take into account when designing preambles? > > > > thanks a lot > > > > > > For the benefit of those who aren't long-distance mind readers, pream=ble> > > to what? > > > > > > Jerry > > > -- > > > Engineering is the art of making what you want from things you can ge=t=2E> > > =AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF > > > > sorry for not being clear. > > > > I am referring to preamble to the data. Normally we need to use > > preamble to do synchronization and channel estimation job.
