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Hello World by Core LTE...

Hello everyone.

Welcome to ShareTechNote.blogspot.com. This blog is dedicated to all the engineers, managers and whoever directly or indirectly working for LTE.

In this blog I will post LTE related articles. LTE is a 3GPP standard specification. I will just try to explain what 3GPP wants to say about LTE in my own words. As no one knows everything, I am also here to learn from my reader. If you find any error or conflict which seems not aligned with 3GPP standards, please inform me. I'll fix it right away.

I will try my best to explain things clearly and everything what I know or found on LTE.



About me:
I am Shekhar Prasad Shaw. I am working in LTE since last about 2.5 Years in Qualcomm as a contract employee. I am a ECE branch student, passed out in 2012 from WBUT.


I thank everyone who visited my blog, read my posts and I'll appreciate if your give your valuable feedback and comments of my posts. Thanks for reading and please share this to your LTE colleagues also. :)

Thanks you very much.

- A Short note from Author, Shekhar.

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Why does PSS & SSS synchronization need?

Before answering the exact question, let's go back little at once UE is switched on. When UE is switched on, it feels there are numerous signal around itself with different frequencies. So, it is now confused, with which signal he has to go with? Which is its right signal? So it starts scanning the radio signals which it supports. UE supports some specific bands. Bands contain a range of frequencies like band 7. Band: 7 Uplink Freq: 2500 - 2570 MHz Downlink Freq: 2620 - 2690MHz So it scans the frequencies which is supported by UE, and read PSS. To know more about how to read PSS and SSS, go to PSS signals  and SSS signals . So, Between UE is turned on and UE starts receiving and sending data it needs to synchronize with it's supported frequencies. This is done by PSS and SSS. Now, Where is PSS transmitted? PSS is transmitted in the last symbol of 0th and 10th slot in a frame. It gets repeated in each 5 msec time interval. [ Click here for the above image

PSS and SSS in LTE (Primary and secondary synchronization signals)

In most of websites I found where do PSS and SSS come and what do these are beneficial for. The thing which most of the LTE learners want to understand is that, "What is exactly those signals?". That is the reason I started this post. PSS & SSS are two synchronization symbols in LTE which help UE (User equipment) to synchronize with network. So, PSS stands for Primary synchronization signal. SSS stands for Secondary synchronization signal. PSS is nothing but a sequence known as Zadoff-Chu Sequence . It comes in last symbol of slot 1 and slot 0. For detail info on where & how does it come, go to PSS and SSS synchronization. Now, What is Zadoff-chu Sequence ? In LTE, Zadoff chu sequence is a combination of complex sequences. These sequences have a special property, known as CAZAC webform. CAZAC stands for " C onstant A mplitude Z ero A utocorrelation". It means when we use this as a synchronization code, the correlation between the ideal sequence

SSS in LTE (secondary synchronization signals)

SSS stands for secondary synchronization signals. SSS comes in the symbol just before PSS comes. If you don't know, how did we detect PSS, then goto this the previous post of  PSS and SSS in LTE (Primary and secondary synchronization signals) SSS is basically an m-sequence or Maximum length sequence. Now, What is m-sequence? M-sequence is a pseudo random binary sequence. These sequence can be generated just by cycling through every possible state of a shift register of length resulting in a sequence of length . Here, Three m-sequences, each of length 31, are used to generate the secondary synchronization signals. SSS Generation Two binary sequences, each of length 31, are used to generate the SSS. Sequences  s 0 ( m 0 )  and  s 1 ( m 1 )  are different cyclic shifts of an  m -sequence,  ˜ s . The indices  m 0  and  m 1  are derived from the cell-identity group,  N ID (2)  and determine the cyclic shift. The values can be read from table 6.11.2.1-1 in "Physical Cha