dc hsdpa features

8/9/2019 DC HSDPA Features

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P-0Huawei RAN12.0 DC-HSDPA Feature Presentation

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Confidential Information of Huawei. No Spreading Without

Permission


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2Huawei RAN12.0 DC-HSDPA Feature Presentation


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The first phase of Multi-Carrier HSPA (MC-HSPA) based on 3GPP R8 Technical


Specifications (TSs) uses two consecutive carriers in the downlink to transmit data

for one subscriber and named as Dual Carrier HSDPA (DC-HSDPA). The 3GPP R9

and beyond TSs specify the use of more than two carriers for a single subscriber

without the restrictions on the use of same frequency band. DC-HSDPA allows a UE to set up HSDPA connections with two inter-frequency

synchronous cells that have the same coverage. In the downlink, the UE can

receive different data through HS-DSCHs from the two cells simultaneously. In the

uplink, however, the UE sends data only through its primary cell.


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In RAN12.0, non-equivalent deployment is not supported.


Within equivalent mode, both of anchor and supplementary cells are configured

with all the physical channels, within non-equivalent mode, only some of physical

channels are configured in supplementary cell. Please refer to next page for more

info.


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DC-HSDPA depends on the two features, HSDPA and downlink enhanced L2.

Huawei RAN12.0 DC-HSDPA Feature Presentation

The anchor-carrier cell and the supplementary-carrier cell must belong to the

same NodeB and must be inter-frequency same-coverage neighboring cells with a

frequency spacing of 5 MHz. In addition, they use different downlink scrambling

codes.

Tcell is configured in each cell, this parameter could be modified by RNC

command MOD UCELLSETUP.

DL enhanced L2 could be activated by RNC command ADD/MOD

UCELLALGOSWITCH. ( RNC license required )


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Parameter RNC command


PS_STREAMING_ON_HSDPA_SWITCH SET UCORRMALGOSWITCH.

DL streaming threshold on HSDPA

SET UFRCCHLTYPEPARADL BE traffic threshold on HSDPA

MIMO_64QAMorDC-HSDPA SET UFRC


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During RB setup or state transition from CELL_FACH to CELL_DCH, the RNC makes


DRDs to select a DC-HSDPA cell group and then select a primary-carrier cell for

the UE.

The procedure is as follows:

1. The RNC selects a set of candidate cells that meet the DRD quality conditions.

For details, see the Directed Retry Decision Feature course.

2. The RNC selects a set of candidate DC-HSDPA cell groups as follows:

From the candidate cell set, the RNC selects a DC-HSDPA cell with the HSPA+

technologies ranked first. The RNC finds the corresponding DC-HSDPA cell group

of this cell. If the other cell in this group is also in the candidate cell set, the RNC

takes this group as the candidate DC-HSDPA cell group and performs step 4.


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3. The RNC select a DC-HSDPA cell group as follows


If there are multiple such DC-HSDPA cell groups and the

ServiceDiffDrdSwitch is on, the RNC selects a group with the highest

service priority.

If different DC-HSDPA cell groups support the same HSPA+

technologies, these groups are ranked on the basis of their service

priorities.

The service priority of a DC-HSDPA cell group is determined by the

highest service priority of the two cells in the group.


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Pmax: maximum DL power of a cell


Pnon-HSPA: DL power used for non-HSPA UEs in a cell

GBPSC-H: DL power required by the HS-PDSCHs to provide GBRs for SC-HSDPA

UEs in a cell.

GBPDC-H: DL power required by the HS-PDSCHs to provide GBRs for the DC-

HSDPA UEs in the DC-HSDPA cell group.

For a DC-HSDPA UE, the RNC performs the CAC based on the total DL power

margin of the DC-HSDPA cell group because the UE can use the DL power margin

of any of the two cells after the admission.

For a non-DC-HSDPA UE, the RNC performs the CAC based on the total DL power

of the serving cell minus the DL power used for the existing non-DC-HSDPA UEs in

this cell. If the admission is successful, the RNC continues to perform the CAC

based on the total DL power margin of the DC-HSDPA cell group.


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When receiving a measurement report indicating that the signal quality of a DC-


HSDPA cell is better than that of the serving cell (a DC-HSDPA cell), the RNC

decides whether to perform a DC-HSDPA handover to the target cell:

If the admission to the target cell is allowed and the corresponding

configuration is successful, the RNC performs the handover.

If the admission to the target cell is allowed but the corresponding

configuration is unsuccessful, the RNC reconfigures the service on SC-

HSDPA and then performs an SC-HSDPA handover.

If the admission to the target cell is not allowed, the RNC reconfigures the

service on DCH and performs a DCH handover:

If the DCH handover is allowed, the RNC performs the handover.

Otherwise, the RNC does not perform the handover.


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When receiving a measurement report indicating that the signal quality of a non-


DC-HSDPA cell is better than that of the serving cell (a DC-HSDPA cell), the RNC

reconfigures the service to DCH or HSDPA and continue handover procedure.


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When receiving a measurement report indicating that the signal quality of a DC-


HSDPA cell is better than that of the serving cell (a non-HSDPA cell), the RNC

performs a handover after which the HSPA+ technologies supported by both the

source cell and the target cell are used in the target cell. If such HSPA+

technologies are ranked lower than some HSPA+ technologies supported by boththe target cell and the UE, the ChannelRetryHoTimerLen timer is started after the

handover. When the timer expires, the RNC tries to reconfigure the traffic radio

bearer (TRB) and signaling radio bearer (SRB) to enable them to support the

higher-ranked HSPA+ technologies.


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The NodeB selects the first cell from the two cells to perform the scheduling


process first.

The NodeB selects a cell based on the cell power load of each cell.

The NodeB selects the cell with lower cell power load for scheduling. If the

cell power loads of the two cells are identical or too high, the NodeBperforms the next step.

The NodeB selects a cell based on the number of SC-HSDPA UEs in each

cell.

The NodeB selects the cell with the smaller number of SC-HSDPA UEs for

scheduling. If the numbers of SC-HSDPA UEs in the two cells are identical,

the NodeB selects a cell for scheduling according to the Round Robin (RR)

strategy.

If the first cell is not capable of transmitting all the data of a UE, the NodeB

selects the second cell to provide service.

After determining the cell, the NodeB needs to determine the queuing of this UE

and other UEs in this cell.

The calculation of the scheduling priority of a DC-HSDPA queue needs to

consider the different CQIs and Uu rates of the two carriers. In the

proportional fair (PF) algorithm and enhanced proportional fair (EPF)

algorithm, R/r used for DC-HSDPA is different from that used for SC-HSDPA:

For SC-HSDPA, R represents the throughput corresponding to the CQI

reported by the UE for this carrier, and r represents the throughput

currently achieved by the UE. A greater R/r value indicates a higher

scheduling priority. For DC-HSDPA, R represents the throughput corresponding to the CQI


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According to the scheduling algorism, each of the DC cells could be scheduled


independently.


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User rate is doubled in DC-HSDPA cells compared to SC-HSDPA cell because of the


full use of resources in two cells.

DC-HSDPA has gain of 2 times anywhere while MIMO causes obvious gain in cell

center only.


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When mono-user is in DC cell, the gain is significant at the cell edge, which is 50%.


When multi-users are in DC cell, transfer time is improved by 50% with DC-HSDPA

for as long as the air interface is not congested.


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The less the user number is, the larger the sector throughput gain.


DC-HSDPA can make full use of the radio resource by joint scheduling.


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System Simulation for full buffer service with 64QAM


In case of plenty of traffic volume, the capacity of system with MIMO is

larger than that with DC-HSDPA because the spectrum efficiency is

improved more by MIMO

The throughput of 10% best users in MIMO cells is 6% more than that in

DC-HSDPA cells


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The DC-HSDPA is recommended to implement in the Non-Capacity Limitation


Scenarios, for example, the some of Urban, Sub-Urban and part of rural… and if

the characteristics of the commercial network’s Traffic-Mode approach to the

Burst Service, the DC-HSDPA will contribute higher gain to the Cell throughput

and the QoS. In the other side, the Capacity Limitation Scenarios, such as Dense Urban, some of

Urban/ Rural, the MIMO is recommended to enhance the spectrum efficiency and

achieve higher cell throughput.


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