The information on which Resource Blocks (RBs) are allocated (Resource Allocation) for both Uplink and Downlink needs to be signalled to the UE.
The Resource
Allocation information is carried on Downlink Control Information (DCI) by Physical
Downlink Control Channel (PDCCH). Resource Allocation field is one of the major
field in the DCI.
In the case of
Uplink, the allocated RBs have to be contiguous in order to guarantee
single-carrier property (SC-FDMA is used in the Uplink). The contiguous nature of resource allocation
requires less number of bits but the scheduler in the eNB will have less
flexibility in allocating the resources.
In the case of
Downlink, the allocated RBs doesn’t need to be contiguous which will require
more bits to signal the Resource Allocation but the eNB’s scheduler will have
more flexibility in allocating the resources.
In LTE, ResourceAllocation Type 0, Resource Allocation Type 1 and Resource Allocation Type 2
are defined.
Resource Allocation
Type 0 and Resource Allocation Type 1 are used for non-contiguous resource
allocation (only for Downlink) which uses bit-map based signaling.
For allocating contiguous resource blocks in the Uplink, Resource Allocation Type 0 is used where as same for downlink it is called as Resource Allocation Type 2.
For allocating contiguous resource blocks in the Uplink, Resource Allocation Type 0 is used where as same for downlink it is called as Resource Allocation Type 2.
The UE shall
interpret the Resource Allocation field depending on the PDCCH DCI Format
detected.
For Uplink, Resource
Allocation information is conveyed on PDCCH DCI Format 0 using Resource
Allocation Type 0.
In the Downlink, PDCCH DCI Formats 1, 2, 2A and 2B uses Resource Allocation Type 0 or Type 1 whereas PDCCH DCI Formats 1A, 1B, 1C and 1D uses Resource Allocation Type 2
Click here for Resource Allocation Type 0 in the Downlink. Check here for Downlink Resource Allocation Type 1.
Uplink Type 0 and Downlink Type 2 are explained in post 'Downlink Resource Allocation Type2 and Uplink Resource Allocation Type0'.
Click here for Resource Allocation Type 0 in the Downlink. Check here for Downlink Resource Allocation Type 1.
Uplink Type 0 and Downlink Type 2 are explained in post 'Downlink Resource Allocation Type2 and Uplink Resource Allocation Type0'.
Reference: 3GPP TS 36.213
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Very interesting! Do you have some info if receive diversity affects how many PRBs are assigned to an UE in uplink?
ReplyDeleteThank you for sharing about Resource scheduling. Keep Sharing it.
ReplyDeleteJust a question:
ReplyDeleteIn srsLTE, scheduling resources in DCI 0 (UL), it's used Allocation Type 2 (contiguous).
In this article it's mentioned: 'For allocating contiguous resource blocks in the Uplink, Resource Allocation Type 0.'
Is this a kind of a typo? Thanks!
How to see which of Resource Allocation Type is currently ussing? In my testbed I only see RAT0. How to make eNb to use RAT1, how to make UE to use RAT2? You wrote: "For allocating contiguous resource blocks in the Uplink, Resource Allocation Type 0 is used where as same for downlink it is called as Resource Allocation Type 2." is it correct when we see RAT0 in downlink it automatically means that RAT2 uses in uplink?
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