rf network planning and optimization service umts performance analysis for multi-carrier capacity...
DESCRIPTION
Rf PlanningTRANSCRIPT
U900*
Performance Gains and Cases
Negative Impacts on KPIs
Policies
The power, code resources, and RTWP of current carriers are limited, or the number of users increases. Consequently, the cell throughput cannot ensure the use experience. Then carriers need to be added to increase the network capacity.
Operators' Requirements
Triggering Factors
Application Scenarios
Overall Policies
Camping policy
Access policy
Connection policy
Mobility policy
DC policy
Improve the carrier usage.
Method: Enable users to randomly camp on several carriers providing continuous coverage and initiate service access. For non-camping carriers, enable users to perform HSPA service load balancing.
R99 Preferred
R99 Preferred
H Preferred
H Preferred
Initial Phase
Mature Phase
R99 Preferred
H Preferred
H Preferred
H Preferred
H Preferred
R99 Preferred
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
R99 Preferred
H Preferred
H Preferred
H Preferred
H Preferred
H Preferred
H Preferred
Voice performance first
*
Transmit power and pilot configurations
The UMTS network is a self-interfering system. After capacity expansion, the number of cell users decreases. The number of users, traffic volumes, and capacity are mutually interactive. Neighboring cells and local cells generate interference to each other, which affects coverage. Consequently, network performance is affected. Besides, discontinuous coverage and usage of features in capacity expansion also affect the network performance.
Capacity expansion
Total PS/CS traffic volume ↑
AMR RAB setup success rate
RRC connection setup success rate
H RAB setup success rate
PS R99 RAB setup success rate
CS call drop rate
PS call drop rate
After capacity expansion, the number of single-cell users decreases, traffic volumes decrease, Ec/Io improves due to cell load decrease, and cell KPIs improves.
RRC connection setup success rate
*
F1
F1
F2
F1
F2
F3
F1
F2
F3
F4
Cell load (TCP/RTWP)
Interference (Ec/Io)
The volume of cell resources allocated to single users increases.
CS voice quality
↓
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
CS/PS access success rate
↑
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
CS/PS handover success rate
↑
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
Total PS traffic volume
↑(cells with limited load or congestion exist)
Congestion is eliminated and the total volume of available resources increases.
Total CS traffic volume
Performance Gains: Traffic Volume Increases
Case from 26 sites where the second carrier is expanded and the third carrier is activated:
*
Page *
Traffic of cells on carriers F1 and F2 are shared by cells on carrier F3, which reduces the air interface load. Gains are determined by the number of service suppressed users before capacity expansion. Specifically, a large number of service suppressed users indicates fewer gains. The common channels also consume some TCP power.
Compared with the same peak hour one week ago, this site obtains the following gains:
The TCP usage decreases by 17%.
The RTWP decreases by 3 dB.
The number of RAB setup failures caused by power congestion decreases.
Performance Gains: The TCP Usage and RTWP Decrease
F1 F2 F3
Page *
After the TCP usage and RTWP decrease in cells on carriers F1 and F2, the Ec/Io improves, uplink interference decreases, and the access success rate becomes stable.
Performance Gains: The Access Success Rate Becomes Stable
F1 F2 F3
Page *
After the TCP usage and RTWP decrease in F1 and F2 cells, the Ec/Io improves, uplink interference decreases, call completion success rate increases, and call drop rate decreases.
Performance Gains: The Call Completion Success Rate Increases
F1 F2 F3
Performance Gains: The Handover Success Rate Improves
After the TCP usage and RTWP decrease in F1 and F2 cells, the Ec/Io improves, uplink interference decreases, mobility is stable, and peak-hour KPI deterioration is relieved.
F1 F2 F3
Negative Impacts on KPIs
Capacity expansion may produce negative impacts on some KPIs, which should be analyzed based on the actual scenarios.
The possible factors that cause negative impacts include: carrier coverage continuity, Iur interface handover policy, camping and service layering policy, state transition, load control policy, and inter-frequency carrier expansion. These factors will be described in the following pages of this document.
The following table lists the affected KPIs:
Note: With consideration to the preceding negative impacts, the capacity expansion policy should consider coverage areas and traffic absorption. The specific policies and algorithm parameters should be adjusted based on the actual scenarios to ensure that the KPIs on the network can improve.
Counter Type
Change Trend
CS/PS access success rate
Preferred camping+service layering policy is applied, LDR inter-frequency load balancing is enabled, and inter-frequency UMTS900 carriers are expanded.
CS/PS handover success rate
Iur relocation success rate
*
Carrier discontinuous coverage produces negative impacts on KPIs.
If the new carriers provide discontinuous coverage, the call drop rate at the coverage edge will increase when the compression mode is started to perform inter-frequency handovers for cell edge users served by new carriers.
Carrier continuous coverage produces no negative impacts on KPIs.
If the new carriers provide continuous coverage, disable the inter-frequency handover function. The KPIs can remain the same.
Mobility
IFHO
SHO
Carriers provide discontinuous coverage and the call drop rate increases.
Carriers provide continuous coverage and the call drop rate is not affected.
F1
F2
F3
F4
F4
F1
F2
F3
F1
F2
F3
F1
F2
F4
Page *
If handovers are allowed over the Iur interface, the Iur relocation success rate will not be affected.
If new carriers are not added on sites served by the SRNC and carrier capacity is not expanded on the sites served by the NRNC, carrier discontinuous coverage occurs. If the Iur interface has been configured with a handover policy, the call drop rate in the coverage edge cells will increase but the Iur relocation success rate will not be affected when the compression mode is started to perform inter-frequency handovers for cell edge users served by new carriers.
If carriers are added on sites served by the SRNC and NRNC to provide continuous coverage, disable the inter-frequency handover. In this case, the call drop rate remains unchanged. If the Iur interface has been configured with a handover policy, the Iur relocation success rate will not be affected.
If handovers are not allowed over the Iur interface, the Iur relocation success rate will be affected.
If handovers are not allowed over the Iur interface, inter-frequency hard handovers with successful relocation will be triggered. Then the Iur relocation success rate will decrease.
F1
F2
F3
F4
F4
F1
F2
F3
F1
F2
F3
F1
F2
F4
SRNC
NRNC
IUR
Mobility
IFHO
SHO
Factor 2 for Negative Impacts on KPIs: Iur Interface Handover Policy
Carriers provide discontinuous coverage and the call drop rate increases.
If handovers are not allowed over the Iur interface, the Iur relocation success rate will decrease.
If handovers are not allowed over the Iur interface,
the Iur relocation success rate will decrease.
*
Page *
Negative impacts on KPIs from preferred camping and service layering policy:
When the preferred camping and service layering policy is applied, the DRD process is started in each PS service access and therefore the access success rate may decrease. The failed rollback in the DRD process also affects the access success rate. If the rollback function is not enabled in the DRD process, the PS access success rate will decline more.
Compared with the non-layering services, if one carrier serving the PS services is reduced, the network capacity in PS hotspots is reduced as well.
If CELL_FACH state transition is enabled in the service layering networks, inter-frequency reselection occurs in the H2F state transition and call drops may occur in the DRD process. On some site sites, the Qualcomm chips cannot normally read the system messages.
If CELL_PCH state transition is enabled, UEs will perform inter-frequency reselection in each H2F or H2P process, during which the DRD is started. As a result, the access failure rate may increase.
Factor 3 for Negative Impacts on KPIs: Camping and Service Layering Policy
Solutions to avoid negative impacts on KPIs in the preferred camping scenarios:
1. Configure the preferred camping policy rather than use the policy barred mode.
2. Enable the SIB4 and ensure that the inter-frequency measurement is not started in the connected mode.
For the preferred camping policy, configure IdleQoffset2sn for the inter-frequency neighboring cells.
F1
F2
F3
F4
F4
PS access success rate ↓
The PS access success rate remains the same.
The call drop rate remains normal.
The random camping and non-service layering policy has no impacts on KPIs.
If the random camping and non-service layering policy is applied, there are no impacts on KPIs.
With the random camping and non-service layering policy, the network capacity can be fully used.
*
The LDR load balancing function has negative impacts on KPIs.
When the HSPA service is carried on more than one carriers, enable the load balancing algorithm to balance the number of HSPA users among different carriers. With the increased number of DRDs, the PS access success rate decreases.
When the LDR inter-frequency load balancing algorithm is enabled, the number of DRDs in congested cells increases and PS call drop rate rises.
Solutions for minimizing the impacts on KPIs when the LDR load balancing function is enabled:
To reduce the number of call drops caused by LDR DRDs, enable the MC DRD algorithm.
Factor 4 for Negative Impacts on KPIs: Load Control Policy
Load balancing algorithm enabled
*
Adding UMTS900 carriers produces negative impacts on KPIs.
Capacity expansion involves frequency refarming, GSM/UMTS interference, UMTS900 bottom-layer networks. After capacity expansion, KPIs deteriorate significantly. Therefore, KPIs should be reviewed after carrier capacity expansion.
The call drop rate for UMTS900 networks is higher than that for UMTS2100 networks.
An increase in the number of times inter-RAT compressed mode times out on the UMTS 900 network causes the success rate of inter-RAT handovers to fall below that of the UMTS 2100 network in the same area. The success rate of inter-frequency handovers in the UMTS 900 network also decreases.
The access success rate on the UMTS900 network also deteriorates.
If the UMTS900 networks are provided by other vendors, and the feature supporting the inter-frequency DRD is unavailable, the call drop rate and access success rate deteriorate, compared with the scenario that all network carrier devices are provided by Huawei.
Factor 5 for Negative Impacts on KPIs: Inter-frequency Carrier Expansion
U900
U2100
SHO
HHO
Blind-HO
R99+H
R99+H
R99+H
H+R99
H+R99
R99+H
The UMTS900 call drop rate increases and access success rate decreases.
The inter-frequency handover success rate decreases.
*
Copyright © 2013 Huawei Technologies Co., Ltd. All Rights Reserved. The information in this document may contain predictive statements including, without limitation, statements regarding the future financial and operating results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied in the predictive statements. Therefore, such information is provided for reference purpose only and constitutes neither an offer nor an acceptance. Huawei may change the information at any time without notice.
Thank you
Performance Gains and Cases
Negative Impacts on KPIs
Policies
The power, code resources, and RTWP of current carriers are limited, or the number of users increases. Consequently, the cell throughput cannot ensure the use experience. Then carriers need to be added to increase the network capacity.
Operators' Requirements
Triggering Factors
Application Scenarios
Overall Policies
Camping policy
Access policy
Connection policy
Mobility policy
DC policy
Improve the carrier usage.
Method: Enable users to randomly camp on several carriers providing continuous coverage and initiate service access. For non-camping carriers, enable users to perform HSPA service load balancing.
R99 Preferred
R99 Preferred
H Preferred
H Preferred
Initial Phase
Mature Phase
R99 Preferred
H Preferred
H Preferred
H Preferred
H Preferred
R99 Preferred
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
H+R99
R99 Preferred
H Preferred
H Preferred
H Preferred
H Preferred
H Preferred
H Preferred
Voice performance first
*
Transmit power and pilot configurations
The UMTS network is a self-interfering system. After capacity expansion, the number of cell users decreases. The number of users, traffic volumes, and capacity are mutually interactive. Neighboring cells and local cells generate interference to each other, which affects coverage. Consequently, network performance is affected. Besides, discontinuous coverage and usage of features in capacity expansion also affect the network performance.
Capacity expansion
Total PS/CS traffic volume ↑
AMR RAB setup success rate
RRC connection setup success rate
H RAB setup success rate
PS R99 RAB setup success rate
CS call drop rate
PS call drop rate
After capacity expansion, the number of single-cell users decreases, traffic volumes decrease, Ec/Io improves due to cell load decrease, and cell KPIs improves.
RRC connection setup success rate
*
F1
F1
F2
F1
F2
F3
F1
F2
F3
F4
Cell load (TCP/RTWP)
Interference (Ec/Io)
The volume of cell resources allocated to single users increases.
CS voice quality
↓
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
CS/PS access success rate
↑
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
CS/PS handover success rate
↑
Load and interference decrease. Congestion in congested cells is eliminated by expanding capacity.
Total PS traffic volume
↑(cells with limited load or congestion exist)
Congestion is eliminated and the total volume of available resources increases.
Total CS traffic volume
Performance Gains: Traffic Volume Increases
Case from 26 sites where the second carrier is expanded and the third carrier is activated:
*
Page *
Traffic of cells on carriers F1 and F2 are shared by cells on carrier F3, which reduces the air interface load. Gains are determined by the number of service suppressed users before capacity expansion. Specifically, a large number of service suppressed users indicates fewer gains. The common channels also consume some TCP power.
Compared with the same peak hour one week ago, this site obtains the following gains:
The TCP usage decreases by 17%.
The RTWP decreases by 3 dB.
The number of RAB setup failures caused by power congestion decreases.
Performance Gains: The TCP Usage and RTWP Decrease
F1 F2 F3
Page *
After the TCP usage and RTWP decrease in cells on carriers F1 and F2, the Ec/Io improves, uplink interference decreases, and the access success rate becomes stable.
Performance Gains: The Access Success Rate Becomes Stable
F1 F2 F3
Page *
After the TCP usage and RTWP decrease in F1 and F2 cells, the Ec/Io improves, uplink interference decreases, call completion success rate increases, and call drop rate decreases.
Performance Gains: The Call Completion Success Rate Increases
F1 F2 F3
Performance Gains: The Handover Success Rate Improves
After the TCP usage and RTWP decrease in F1 and F2 cells, the Ec/Io improves, uplink interference decreases, mobility is stable, and peak-hour KPI deterioration is relieved.
F1 F2 F3
Negative Impacts on KPIs
Capacity expansion may produce negative impacts on some KPIs, which should be analyzed based on the actual scenarios.
The possible factors that cause negative impacts include: carrier coverage continuity, Iur interface handover policy, camping and service layering policy, state transition, load control policy, and inter-frequency carrier expansion. These factors will be described in the following pages of this document.
The following table lists the affected KPIs:
Note: With consideration to the preceding negative impacts, the capacity expansion policy should consider coverage areas and traffic absorption. The specific policies and algorithm parameters should be adjusted based on the actual scenarios to ensure that the KPIs on the network can improve.
Counter Type
Change Trend
CS/PS access success rate
Preferred camping+service layering policy is applied, LDR inter-frequency load balancing is enabled, and inter-frequency UMTS900 carriers are expanded.
CS/PS handover success rate
Iur relocation success rate
*
Carrier discontinuous coverage produces negative impacts on KPIs.
If the new carriers provide discontinuous coverage, the call drop rate at the coverage edge will increase when the compression mode is started to perform inter-frequency handovers for cell edge users served by new carriers.
Carrier continuous coverage produces no negative impacts on KPIs.
If the new carriers provide continuous coverage, disable the inter-frequency handover function. The KPIs can remain the same.
Mobility
IFHO
SHO
Carriers provide discontinuous coverage and the call drop rate increases.
Carriers provide continuous coverage and the call drop rate is not affected.
F1
F2
F3
F4
F4
F1
F2
F3
F1
F2
F3
F1
F2
F4
Page *
If handovers are allowed over the Iur interface, the Iur relocation success rate will not be affected.
If new carriers are not added on sites served by the SRNC and carrier capacity is not expanded on the sites served by the NRNC, carrier discontinuous coverage occurs. If the Iur interface has been configured with a handover policy, the call drop rate in the coverage edge cells will increase but the Iur relocation success rate will not be affected when the compression mode is started to perform inter-frequency handovers for cell edge users served by new carriers.
If carriers are added on sites served by the SRNC and NRNC to provide continuous coverage, disable the inter-frequency handover. In this case, the call drop rate remains unchanged. If the Iur interface has been configured with a handover policy, the Iur relocation success rate will not be affected.
If handovers are not allowed over the Iur interface, the Iur relocation success rate will be affected.
If handovers are not allowed over the Iur interface, inter-frequency hard handovers with successful relocation will be triggered. Then the Iur relocation success rate will decrease.
F1
F2
F3
F4
F4
F1
F2
F3
F1
F2
F3
F1
F2
F4
SRNC
NRNC
IUR
Mobility
IFHO
SHO
Factor 2 for Negative Impacts on KPIs: Iur Interface Handover Policy
Carriers provide discontinuous coverage and the call drop rate increases.
If handovers are not allowed over the Iur interface, the Iur relocation success rate will decrease.
If handovers are not allowed over the Iur interface,
the Iur relocation success rate will decrease.
*
Page *
Negative impacts on KPIs from preferred camping and service layering policy:
When the preferred camping and service layering policy is applied, the DRD process is started in each PS service access and therefore the access success rate may decrease. The failed rollback in the DRD process also affects the access success rate. If the rollback function is not enabled in the DRD process, the PS access success rate will decline more.
Compared with the non-layering services, if one carrier serving the PS services is reduced, the network capacity in PS hotspots is reduced as well.
If CELL_FACH state transition is enabled in the service layering networks, inter-frequency reselection occurs in the H2F state transition and call drops may occur in the DRD process. On some site sites, the Qualcomm chips cannot normally read the system messages.
If CELL_PCH state transition is enabled, UEs will perform inter-frequency reselection in each H2F or H2P process, during which the DRD is started. As a result, the access failure rate may increase.
Factor 3 for Negative Impacts on KPIs: Camping and Service Layering Policy
Solutions to avoid negative impacts on KPIs in the preferred camping scenarios:
1. Configure the preferred camping policy rather than use the policy barred mode.
2. Enable the SIB4 and ensure that the inter-frequency measurement is not started in the connected mode.
For the preferred camping policy, configure IdleQoffset2sn for the inter-frequency neighboring cells.
F1
F2
F3
F4
F4
PS access success rate ↓
The PS access success rate remains the same.
The call drop rate remains normal.
The random camping and non-service layering policy has no impacts on KPIs.
If the random camping and non-service layering policy is applied, there are no impacts on KPIs.
With the random camping and non-service layering policy, the network capacity can be fully used.
*
The LDR load balancing function has negative impacts on KPIs.
When the HSPA service is carried on more than one carriers, enable the load balancing algorithm to balance the number of HSPA users among different carriers. With the increased number of DRDs, the PS access success rate decreases.
When the LDR inter-frequency load balancing algorithm is enabled, the number of DRDs in congested cells increases and PS call drop rate rises.
Solutions for minimizing the impacts on KPIs when the LDR load balancing function is enabled:
To reduce the number of call drops caused by LDR DRDs, enable the MC DRD algorithm.
Factor 4 for Negative Impacts on KPIs: Load Control Policy
Load balancing algorithm enabled
*
Adding UMTS900 carriers produces negative impacts on KPIs.
Capacity expansion involves frequency refarming, GSM/UMTS interference, UMTS900 bottom-layer networks. After capacity expansion, KPIs deteriorate significantly. Therefore, KPIs should be reviewed after carrier capacity expansion.
The call drop rate for UMTS900 networks is higher than that for UMTS2100 networks.
An increase in the number of times inter-RAT compressed mode times out on the UMTS 900 network causes the success rate of inter-RAT handovers to fall below that of the UMTS 2100 network in the same area. The success rate of inter-frequency handovers in the UMTS 900 network also decreases.
The access success rate on the UMTS900 network also deteriorates.
If the UMTS900 networks are provided by other vendors, and the feature supporting the inter-frequency DRD is unavailable, the call drop rate and access success rate deteriorate, compared with the scenario that all network carrier devices are provided by Huawei.
Factor 5 for Negative Impacts on KPIs: Inter-frequency Carrier Expansion
U900
U2100
SHO
HHO
Blind-HO
R99+H
R99+H
R99+H
H+R99
H+R99
R99+H
The UMTS900 call drop rate increases and access success rate decreases.
The inter-frequency handover success rate decreases.
*
Copyright © 2013 Huawei Technologies Co., Ltd. All Rights Reserved. The information in this document may contain predictive statements including, without limitation, statements regarding the future financial and operating results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied in the predictive statements. Therefore, such information is provided for reference purpose only and constitutes neither an offer nor an acceptance. Huawei may change the information at any time without notice.
Thank you