LTE Questions & Answer

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  • 7/17/2019 LTE Questions & Answer

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    Mohamed Khalil commented on a group discussionJoin group3GPP LTE/LTE-A Standards3GPP LTE/LTE-A StandardsWhy HARQ ( PHICH) information in MIB?What is necessary of adding PHICH information in MIB, why cant in SIB1 or SIB2?LikeComment11 person likes this.55 comments.Osama Bazan2dOsama Bazan:SIB1 and SIB2 are sent on DL-SCH that required scheduling information to be sent on PDCCH. In order for the UE to understand PDCCH resource mapping, it needs first to know PHICH resource mapping from BW, Ng and PHICH duration which are all sent in MIB show lessMohamed Khalil1dMohamed KhalilSalam Osama Question please: Why PHICH info is important to read PDCCH?Melwyn Lobo23hMelwyn Lobo:Its needed in case of Non-adaptive transmission cases.In this case, UE/terminal figures out it is using "Non adaptive" HARQ if it gets NACK on PHICH but does not get DCI0 over PDCCH, so UE choses to use some knownvalues for RV and MCS. show lessOsama Bazan5hOsama Bazan@Mohamed: The REs in first few symbols of each subframeare shared among RS, PCFICH, PHICH and PDCCH. After UE gets the PCI and BW, it can recognize the REs used by the RS and PCFICH. In order to know the REs used byPDCCH, the UE must first know the REs used by PHICH using the PHICH info in MIBshow lessMohamed Khalil3hMohamed Khalil@ossama :Thanks for very clear answer