SYSTEM AND METHOD FOR LINK ADAPTATION AND SCHEDULER ENHANCEMENTS FOR UL SLOT AGGREGATION
Systems and methods for link adaptation and to allocate and schedule transport blocks for UE slot aggregation.
1 . A system comprising:
a New Radio (NR) base station comprising a link adaptation and resource allocation module configured to allocate resources in both time (K slots) and frequency domain (M Physical Resource Block (PRB)s) for a UE doing slot aggregation, the allocation comprising;
in the frequency domain, the allocation is M PRBs in a slot, with the total number of PRBs given as K×M; and
a total number of PRBs available across the K slots is same as a single grant with the K×M PRB allocation;
so that a transport block can be transmitted with multi-slot allocation the K slots x the M PRBs with a modulation and coding scheme (MCI i ) decided by a link adaptation algorithm of the a link adaptation and resource allocation module, the link adaptation algorithm deciding a same allocation as a single allocation of the K×M PRBs with the MCI i , and which is greater than K times a size of the transport block of an M PRB allocation with MCI i .
2 . The system of claim 1 , comprising:
the link adaptation and resource allocation module of the base station being configured to, when executed by the processor, convey a higher TB size to a UE so that the UE can send a Voice over New Radio (VoNR) packet without segmentation in a multi slot transmission, the UE being configured to send the same encoded packet to each slot with different redundancy versions;
wherein the system is configured so that some of the initial transmission of the multi-slot bundle transmission results in cyclic redundancy check (CRC) failures at a receiver of the base station, however once more receptions of the transmission happen, and a code rate is reduced to a level a channel supports, the VoNR packet is successfully decoded in the base station; and
at a last slot of the multi-slot transmission, the base station decodes the VoNR packet successfully with more than 99% probability.
3 . The system of claim 1 , wherein a modulation and coding scheme (MCS) downlink control information (MCS dci ) is configured to be signaled to the UE; and
the UE is configured to send:
X bits in an uplink (UL), where X corresponds to size of one or two VoNR packets as a payload; and
the MCS dci when meeting an MCS dci condition.
4 . The system of claim 3 , wherein the MCS dci . condition comprises:
condition 1) X being less than or equal to computed transport block size with a signaled MCS dci , signalled number PRB dci (TBsize(MCS dci , PRB dci )); and
condition 2) the computed transport block size being less than or equal to a max supported transport block size computed with the MCS calculated by the link adaption module for UE MCI i and allocation size of N times signaled PRBs, where
N
×
PRB
dci
(
TBsize
(
MCI
i
,
K
×
PRB
dci
)
)
X
≤
TBsize
(
MCS
dci
,
PRB
dci
)
≤
TBsize
(
MCI
i
,
K
×
PRB
dci
)
where TBsize(R, P) is a function to determine a predefined transport block size for MCS ‘R’ and ‘P’ PRBs;
PRB dci is decided by the link adaptation and resource allocation module based on UE transmit parameters; and
K is the number of repetitions in a multi-slot transmission.
5 . The system of claim 4 , wherein the system is configured to execute a method for finding MCS dci comprising:
the base station configured to increment the MCS from MCS i to MCS max by at least:
a) for the MCS, determine the transport block size with signaling PRBs TBsize(MCS, PRB dci );
b) if the transport block size satisfies both condition 1) and condition 2) for MCS dci , set the MCS as MCS dci . and signal the grant to the UE through a DCI, with MCS set to MCS dci , and #PRBs as PRB dci .;
if condition 1) satisfied but condition 2) fails, where the transport block size with a MCS is greater than the max supported transport block size, then the base station allocates a smaller MCS to the UE than required for X bits by setting MCS dci =MCS−1 and signals the grant to the UE through DCI, with MCS set to MCS dci , and #PRBs as PRB dci ;
if condition 1) fails and the computed transport block is less than required X bits and a supported transport block size, increment the MCS and go to a);
if both condition 1) and condition 2) fail, the base station is configured to give a smaller allocation to the UE than required for X bits by setting MCS dci =MCS−1, and the grant through downlink control information (DCI) is signaled to the UE, with MCS set to MCS dci , and #PRBs as PRB dci .
6 . The system of claim 5 , wherein the UE is configured to segment the packet when the grant through DCI, with MCS set to MCS dci , and #PRBs as PRB dci is signaled for when condition 1) satisfied but condition 2) is failed, or if the grant for both condition 1) and condition 2) fails.
7 . The system of claim 4 , wherein, to reduce the search for MCS dci , the system is configured to specify a configurable minimum MCS value based on expected VoNR packet size and minimum MCS of the UE and number of repetitions.
8 . The system of claim 5 , wherein the system is configured to find MCS dci , by at least:
changing the number of repetitions K slots in multi-slot transmission, whereby K can take values from a predefined set, and optimized values for MCI dci , K, PRB dci are found that satisfy the UE BSR requirement X which also satisfy the conditions 1) and 2):
X
≤
(
TBsize
(
MCS
dci
,
PRB
d
c
i
)
≤
TBsize
(
MCI
i
,
K
*
PRB
dci
)
.
9 . The system of claim 8 , comprising:
the base station being configured to increment the K from 1 to K max as per the predefined set, where for each value of K, increase allocated PRBs ‘P’ from 1 to PRB max , wherein MCS MCS i , max PRB allocation PRB max , maximum repetition is K max , where PRB max and K max are configurable values.
10 . The system of claim 8 , wherein the system is configured to at least:
(a1) for the MCI i , and K repetitions, and P PRBs determine the max transport block size TBsize(MCI i , K*P);
(b1) if X is less than or equal to the max supported transport size of the UE for P PRBs, search for MCS dci as given in feature 5 for MCS dci ;
(c1) if the transport block size satisfies as given in feature 5 for MCS dci , then set the MCS as MCS dci and signal the grant to UE through a DCI, with MCS set to MCS dci , and #PRBs as PRB dci ;
(d1) if condition for MCS dci is not satisfied and P is less than PRB max , increment the PRBs P by one, and go to (a); and
(e1) if for MCS dci is not satisfied, but P is equal to PRB max , and K is less than K max increment K to next value possible value from the set and go to step (a1); and
(f1) if the condition for MCS dci is not satisfied, but P is equal to PRB_max, and PRB max , and K is equal to K max , identify the maximum MCS dci so that the transport block size with P PRBs TBsize(MCS dci , P) is less than or equal to the max transport block size TBsize(MCI i , K*P) and signal to UE the grant through DCI, with MCS set to MCS dci , and #PRBs as P, number of repetitions set to K.
10 . A method for slot aggregated user equipment (UEs) executing inter slot hopping and configured to avoid allocation overlapping Physical Random Access Channel (PRACH) in a slot, the method comprising:
when PRACH is on even subframe lower Physical Resource Block (PRB), a base station multi slot scheduler schedules a new transmission on even slot upper PRBs;
when PRACH is on an even subframe Upper PRB, the multi slot scheduler schedules a new transmission on an odd slot upper PRBs;
when PRACH is on an odd subframe Lower PRB, the multi slot scheduler schedules a new transmission on odd slot upper PRBs; and
when PRACH is on odd subframe Upper PRB, multi slot scheduler schedules a new transmission on an even slot upper PRBs.
11 . A method for optimized packing for multiple user equipment (UEs) comprising:
to increase a Physical Uplink Shared Channel (PUSCH) capacity, scheduling higher aggregation UEs first such that a higher AggregationFactor UE has a high priority if a P_LC is multiplied by the AggregationFactor, wherein for UE selection the UE priority is calculated:
P_UE
=
P_LC
*
AggregationFactor
+
P_GBR
+
P_PF
,
or
P_UE
=
(
P_LC
+
P_GBR
+
P_PF
)
*
AggregationFactor
;
where:
P_LC: is Priority based on 5QI QoS;
Slot Aggregation applies when 5QI=1 (VoNR), When 5QI!=1 then AggregationFactor=1;
P_GBR is Priority calculated based on a Guaranteed Bit Rate (GBR) metric;
P_PF is Priority calculated based on a fairness metric; and
the higher Aggregation UE is scheduled if the slot number % AggregationFactor=0.