In LTE, is is possible to perform different modulation schemes on different resource elements in a resource block of a user?
It would be appreciated if you supply me with helpful articles or books.
thanks in advance
http://rfmw.em.keysight.com/wireless/helpfiles/89600b/webhelp/subsystems/lte/content/lte_overview.htm
Dear Faten,
Hope you are well,
Yes it is possible to change the order of modulation even down to the level of the subcarrier. This is due t to that the every sub carrier is M-QAM modulated. M depends on the channel sate information. If the S/N ratio is high, then one can use high order modulation. The modulation is a function of the CSI what i determined by the MAC controller. When ever CSI changed the M changes correspondingly.
So, the CSI updating depends on the channel condition that if the user is far the order will be lower. If the user moves with higher speed the M will be decreased and changed in a higher pace.
Best wishes
Dear Faten,
Yes every resource block can have different modulation order since even every subcarrier can have its own modulation order.
Best wishes
Faten,
The previous answer is correct and complete - each subcarrier's modulation is independently chosen based on the SNR there.
The resource elements are only afterwards bonded into resource blocks (12 carriers high and 1 slot (6 or 7 symbols) wide) for allocation to UEs.
Y(J)S
Dear Faten Bd
I hope you are well,
There are various modulation options available for LTE resource block allocation (BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM) depending on channel conditions. This modulation scheme is applied to all the resource blocks allocated to the user; in other words, each subcarrier in each of the allocated resource blocks are modulated using one of the above-mentioned schemes.
This means that if 16-QAM has been chosen, subcarrier 1 in resource block 1 will be modulated with 16-QAM, resource block 2 subcarrier 1 also with 16-QAM, and so on for all subcarrieres within that resource block and all other resource blocks allocated to the user.
I hope you'll find this file useful
https://www.diva-portal.org/smash/get/diva2:830399/FULLTEXT01.pdf
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