INTRODUCTION
The UL-Smart feature performs centralized coordination for the radio resource of all cells to enhance the cell performance. In this case, each eNB allocates the physical radio resource to UE based on the results of the coordination.
BENEFIT
This will result in performance enhancement for UL data transmission.
DEPENDENCY AND LIMITATION
Dependency
This feature works with Smart Scheduler server which supports C-RAN only, D-RAN only, or H-D-RAN.
This function needs time synchronization.
This feature follows DL Smart (LTE-ME6004) feature in terms of the network architecture, interfaces, and so on.
Limitation
The number of cells supported by a Smart Scheduler server is different according to the type of the server.
FEATURE DESCRIPTION
The network for UL-Smart is consisted of one Smart Scheduler and a large number of eNBs. Samsung supports three types of UL-Smart networks as C-RAN, D-RAN, and H-RAN. Each network diagram is referred from the following figures.
(A) C-RAN
(B) D-RAN
(C) H-RAN
Each eNB is connected with Smart Scheduler server and is classified as C-RAN eNB, and D-RAN eNB according to the transmission delay between Smart Scheduler server and eNB.
In figure (A), C-RAN eNB is concentrated with Smart Scheduler, so C-RAN network guarantees short transmission delay less than 1ms. Each RU distributed from C-RAN eNB is connected with DU using the dark fiber.
D-RAN eNB is shown in figure (B) and is distributed from Smart Scheduler using Ethernet network connection with transmission delay longer than 1ms.
Smart Scheduler server can support inter-cell interference coordination via same structure for C-RAN and D-RAN. Thus, Smart Scheduler server can support UL-Smart although C-RAN eNB and D-RAN eNB are co-located in H-RAN
environment. H-RAN network is shown in figure (C).
In each network architecture, if there is no Smart Scheduler, eNBs can provide stand-alone operation.
The following figure shows the software structure of Smart Scheduler network:
The following functions are performed by each SW block:
Coordinator in Smart Scheduler server
oDetermines inter-interference relation between serving cell and neighbor cells based on SRS.
oGenerates allocation pattern using load information and inter-cell interference relation to improve the performance of cell edge UE.
oTransfers resource allocation pattern to RT-Scheduler.
UE Manager in Smart Scheduler server
oDetermines (1) cell edge UEs based on SRS
oDetermines (2) which of cells receive inter-cell interference from UE of the serving cell based on SRS.
oTransfers UE‟s information (1) and (2) to RT-Scheduler, and information (2) to Coordinator.
RT-Scheduler in eNB
oTransfers load information, such as the amount of inter-cell interference which UEs generate in the serving and amount of inter-cell interference which the serving cell receives from neighbor cells, to Coordinator.
oAllocates resource using UE‟s information and resource allocation pattern.
UL-smart feature performs the scheduling according to the following procedure:
1 RT-Scheduler calculates the amount of inter-cell interference which UEs generate in the serving and amount of inter-cell interference which the serving cell receives from neighbor cells. And then RT-Scheduler transfers them to Coordinator in Smart Scheduler server.
2 UE Manager determines (1) cell edge UE and (2) which of cell receive inter-cell interference from UE of serving cell based on SRS. And then UE Manager transfers UE‟s information (1) and (2) to RT-Scheduler, and information (2) to Coordinator.
3 Coordinator determines inter-interference relation between cells based on SRS.
And then coordinator generates allocation pattern using load information and inter-cell interference relation.
4 Coordinator transfers resource allocation pattern to RT-Scheduler.
5 RT-Scheduler allocates resource to UEs using UE‟s information and resource allocation pattern for cell edge UEs to avoid inter-cell interference from neighbor cells.
SYSTEM OPERATION
How to Activate
This feature is an optional feature and can be activated and deactivated.
Execute the RTRV-SMTUL-SCHED command to retrieve the configuration information of smart uplink scheduling.
Execute the CHG-SMTUL-SCHED command to change the configuration information of smart uplink scheduling in units of smart scheduler server.
oIf the value of ulSmartCsOnOff is '0', the state of UL smart is OFF.
oIf the value of ulSmartCsOnOff is not '0', the state of UL smart is ON. (The recommended value of ulSmartCsOnOff is '3')
Key Parameters
RTRV-SMTUL-SCHED/CHG-SMTUL-SCHED
Parameter Description
dbIndex This is just db index.
ulSmartCsOnOff This parameter enables or disables the coordinated scheduling (CS) of UL smart.
If ulSmartCsOnOff = 0, coordinated scheduling is OFF (false).
If ulSmartCsOnOff = 1, coordinated scheduling using start RB index is ON (true). RT-Scheduler can allocate the resource from the lowest RB index or from the highest RB index for cell edge UE to avoid inter-cell interference between neighbor cells.
If ulSmartCsOnOff = 2, coordinated scheduling using edge pattern is ON (true).
Counters and KPIs
There is no related counter and KPI.
REFERENCE
[1] 3GPP TS 36.101 „Evolved Universal Terrestrial Radio Access (E-UTRA);
User Equipment (UE) radio transmission and reception‟
[2] 3GPP TS 36.211 „Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical Channels and Modulation‟
[3] 3GPP TS 36.212 „Evolved Universal Terrestrial Radio Access (E-UTRA);
Multiplexing and channel coding‟
[4] 3GPP TS 36.213 „Evolved Universal Terrestrial Radio Access (E-UTRA);
Physical layer procedures‟
[5] 3GPP TS 36.300 „Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2‟
[6] 3GPP TS 36.331 „Evolved Universal Terrestrial Radio Access (E-UTRA);
Radio Resource Control (RRC); Protocol specification‟
[7] 3GPP TR 36.814 „Evolved Universal Terrestrial Radio Access (E-UTRA);
Further advancements for E-UTRA physical layer aspects‟
[8] 3GPP TR 36.819 „Coordinated multi-point operation for LTE physical layer aspects‟
[9] 3GPP TR 36.913 „Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN)‟