1 VODAFONE C3 CONFIDENTIAL
Understanding how Vodafone Spain are managing their HSPA network to ensure optimum performance
Mobile Network Optimisation
Vienna 6th‐9th June 2011
Aitor Garcia Viñas
–
Vodafone Spain – Access Department
2 VODAFONE C3 CONFIDENTIAL
THE WAY WE HAVE BEEN SEEING THE NETWORK IS CHANGING
SMARTPHONES ARE THERE
3 VODAFONE C3 CONFIDENTIAL
SMARTPHONE EVOLUTION IN VODAFONE SPAIN
sep-10 oct-10 nov-10 dic-10 ene-11
M B/M onth Device Number
Smartphone Evolution in Vodafone Spain
+14%+65%
4 VODAFONE C3 CONFIDENTIAL
Understanding traffic mix and profiles in an existing HSPA
network to
improve HSPA Data performance
21%
31%
48%
95.74%
0.36%3.89%
Smartphones & modem data traffic
modem
mobile phone
smartphone
% devices with PS traffic
% total traffic
5 VODAFONE C3 CONFIDENTIAL
Understanding Device Requirements
•Mobile Phones:–
Voice quality and mobility
•Modems:–
User peak and average throughput
–
RNC data traffic processing load
–
DL interference
•Smartphones:–
Number of simultaneous users
–
RNC signalling processing load
–
UL interference
XXXXXX
RRU
Antenna
BBU
RNC
Node B
Different capacity issues depending on device type
Mobile Phones Modems Smartphones
MARKET DIRECTION
VOICE
DATA
VOICE + DATA
6 VODAFONE C3 CONFIDENTIAL
Understanding Capacity Requirements
•Capacity Improvement in DL: More steps
and more resources (power and codes)
•Better optimised for multi‐user
•Capacity Improvement in UL: Less and bigger
steps than in DL
•Simultaneous user affects significantly the
cell capacity
•Baseband consumption is very demanding
714
21
4228
84
10 codes 16QAM
15 codes 16QAM
Multi Carrier
MIMO
15 codes 64QAM
Combinations
2
5.7
11.5
10ms
2ms
Multi Carrier or 16QAM
Multi Carrier + 16QAM22
7 VODAFONE C3 CONFIDENTIAL
DL Cell Capacity and User Performance Enhancement
Dl
R99
HSDPA+ 64QAM
HSDPA 16QAM
11
0100
10
1111
111111
Scheduler
&
TFRC
Selection
HARQ
HARQ
Turbo
encoder
Turbo
encoder
Modulation
Spreading
Scrambling
Modulation
Spreading
Scrambling
•W11
•W12
•W21
•W22
•P‐CPICH
•S‐CPICH
Precoding
matrix
calculation
•W1•W2•W3•W4
•Pre‐coding control info•(PCI) from UE
R99 R99/HSDPA
R99
R99/HSDPA
R99/HSDPA+
R99/HSDPA+
5, 10 , 15 codes
5, 10 , 15 codes 15 codes
HSDPA+ WORLD: 64QAM, MIMO and Carrier Aggregation
MIMO 28.8Mbps
MULTI CARRIER 42.2Mbps
DUAL CARRIER +MIMO Up to
84Mbps
64QAM
21.8Mbp
s
384kbps Up to 10.8Mbps
Up to
84Mbps
8 VODAFONE C3 CONFIDENTIAL
Inter‐carrier Load Sharing vs
Non‐Load Sharing
•
15% CS Call drop rate improvement in
Smartphones
•
50% PDP Context activation time
•
Throughput improvement in node B
with high load: +15% DL and +10% UL *
•
Downlink and Uplink Noise distributed in
both layers
R99/HSDPA+
R99/HSDPA+ Cell barred
Any HSPA call to F2No HSPA call established in F1No interfreq
reselection
F2
F1 R99/HSDPA+
R99/HSDPA+
Full HSPA&R99 load balanceInterfreq
resel. allowed
F2
F1
Voice Only layer
HSPA and MRAB Layer
Complete sharing of traffic 50%/50% obtained unbarring F2 and making use of full load sharing
* Benefit seen by drive test
All users camp in F1PS Redirection to F2
Voice and data
redirection and
reselection
based on load
and quality
9 VODAFONE C3 CONFIDENTIAL
HSPA+ 64QAM, MIMO and Dual Carrier
Throughput Comparison at Different Radio Conditions (Mbps)
6.1
2.5
9.0
3.5
20.7
9.6
5.1
21.0
11.1
5.1
10.8
14.2
Good Radio Medium Radio Bad Radio
HSPA + 64QAMHSPA+ MIMOHSPA+ Dual Carrier 64QAM (20W)HSPA+ Dual Carrier 64QAM (40W)
Spectrum Efficiency Comparison at different Radio Conditions (Bits/Hz)
1.2
2.2
0.7
1.8
2.8
0.5
1.0
2.1
0.5
1.1
2.1
0.5
Good Radio Medium Radio Bad Radio
HSPA+ 64QAMHSPA+ MIMOHSPA+ Dual Carrier 64QAM (20W)HSPA+ Dual Carrier 64QAM (40W)
•
HSPA+ DC almost doubles HSPA+ 64QAM
throughput
•
MIMO sometimes unstable in good radio
•
Impact on legacy users due to MIMO data
and S‐CPICH Channel
•
40W Power availability performance
improvement not significant
•
But best spectrum efficiency for MIMO: highly
advisable for high loaded scenarios where DC
reduces its performance
Note: Tests performed on a cluster having average traffic load
according to VF‐ES traffic profile performing FTP downloads
10 VODAFONE C3 CONFIDENTIAL
Enhanced Virtual Antenna Mapping to cope with MIMO 2
VAM
matrixPA2
PA1∑
Rel’99 / HSMIMO stream #1
Primary Pilot
∑MIMO stream #2
Secondary Pilot
V1
V2
Virtual Antennas
(what the UE believes is transmitted)
Physical Antennas
(what the UE is actually transmitted)
Ant 1
Ant 2
θPhase adaptation to
Optimise power received
by HSPA users
CQI reporting from HSPA users
E-VAM algorithm
Enhanced VAM (E-VAM)
allows to dynamically control the phase offset between with the following objectives:
1)
Minimise interference from MIMO2 (virtual antenna 2 signals seen as interference for HSPA users).
2)
Maximise the throughput of HSPA legacy users (independently from MIMO).
Enhanced VAM (E-VAM)
was developed to build upon the partial
success of VAM by insertion of phase after
the signal passes the VAM matrix to one
of the output ports only
11 VODAFONE C3 CONFIDENTIAL
eVAM
to cope with MIMO 2 and improve coverage
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
cdf (
%)
CQI
E-VAM
VAM
E‐VAM activated at BH in VF
ES commercial Network with
high HSDPA traffic load with
no MIMO users present
Around 0.8dB average CQI
improvement achieved
0
5
10
15
20
25
Baseline ‐ 7.2 Mbps "14.4" Mbps MIMO HS ‐ HS HS ‐ MIMO VAM HS ‐ MIMO E‐VAM MIMO ‐ MIMO
user 2user 1
Mbp
s
single active user concurrent active users
DL throughput (good radio conditions)
Legacy throughput
degradation due to
MIMO 2
12 VODAFONE C3 CONFIDENTIAL
UL Cell Capacity and User Performance Enhancement
1.
Rake Receiver:
Place fingers on path delays Maximise Self Power
2.
Equaliser Receiver:
Add extra fingers to suppress the self interference Combat self interference
3.
Time Division Mux
Receiver:
Allocate different TTIs
to each user Combat intra‐cell interference + Interference Cancellation Receiver: Suppress dominant intra‐ and inter‐cell interference Maximise received SIR
4.
Dynamic Noise level and BLER target Increase cell capacity adapting to user location and traffic mix
5.
16QAM Increase spectrum efficiency + Multi Carrier Increase peak and average user throughput
2 4 51 3
TIMETODAY
Up to 3.2Mbps Up to 4Mbps Up to 6Mbps ? Mbps (Max 21 Mbps)
13 VODAFONE C3 CONFIDENTIAL
UL Expected Cell Capacity in multi‐user environment
2ms HSUPA User
10ms HSUPA User
2ms User Mix 10ms User Mix 2ms + 10ms User Mix
•
Significant cell capacity reduction with the 3rd user in the system
•
UL Cell capacity will depend on user location and 2ms to 10ms HSUPA user traffic mix due to
scheduler fairness
•
No Capacity gain when putting 3x2ms users vs
having 10ms in the system
Expected Max cell capacity 10ms: 1 user 1.7 Mbps, 2 user: 2.4 Mbps, 3 user 2MbpsExpected Max cell capacity 2ms: 1 or 2 user 4Mbps, 3 user: 3Mbps, 4 user 2Mbps
1
14 VODAFONE C3 CONFIDENTIAL
UL Receiver Equaliser and SIR Optimisation
2ms HSUPA Average Application Throughput comparison with Equaliser and SIR
•Equaliser benefit depends on layer type and traffic mix: over 8%
•Power control optimisation improves over 20% the average throughput
2
15 VODAFONE C3 CONFIDENTIAL
UL Interference Cancellation
+12%
+61% +51% +28%
•
Cell throughput gain between 12% and 61% depending on HSUPA user
combination
•
Major increase observed for HSUPA 5.76Mbps when HSUPA 2Mbps user
throughput is near its
achievable maximum rates (1.7Mbps)
2ms HSUPA User
10ms HSUPA User
3 x 10ms Use
rs
1 x 10
ms + 1 x 2ms Use
rs
2 x 10ms + 1 x 2ms Use
rs
2 x 2m
s Use
rs
Interference Cancellation feature benefits for different types of user mix
3
16 VODAFONE C3 CONFIDENTIAL
DL and UL Short Term Key Features: Fast Dormancy
•
Fast Dormancy enables the direct transition to cell‐PCH from
cell‐DCH or cell‐FACH for some specific UE’s
•
Pre‐Rel
8 Fast dormancy can be triggered by two reasons:1.
UE sends RRC Con. release to indicate no more data to send
2.
RNC detects no data from/to the UE during a certain period of time
•
Avoid scenarios with high signaling generated by UE’s
or
Paging channel congestion
•
Battery saving and better user experience
XX
XXX
X
RRU
Antenna
BBU
RNC
Nod
e B
SGSN
GGSN
DL and UL Baseband CE > 10%
Radio Links established > 20%
FACH usage > 7%
Significant Control plane load decrease
Very high #PS
RAB and Paging
reduction
CELL_DCH
CELL_FACH
CELL_PCH
URA_PCH
IDLE
FAST
DORMANCY
Call Drop Rate
increased for
specific UE’s
so
white list based
fast dormancy
generated
Pre or Post Rel‐8
devices
17 VODAFONE C3 CONFIDENTIAL
DL and UL Short Term Key Features: Traffic Offload
XX
XXX
X
RRU
Antenna
BBU
RNC
Nod
e B
SGSN
GGSN
WIFI NETWORKINTERNET
Traffic Offload
WIFI OFFLOAD NODE B OFFLOAD RNC OFFLOAD
TYPICAL 3G E2E
DATA CONNECTION
WITH OR WITHOUT
ONE TUNNEL
18 VODAFONE C3 CONFIDENTIAL
DL and UL Short Term Key Features: Coverage Improvement
UMTS2100 F2
UMTS900
UMTS2100 F1
Traffic Steering
Traffic SteeringMobility
Mobility
RRU
Passive Antenna
with Macro
equipment
Passive Antenna
With RRUActive Antenna
CARRIER 1CARRIER 2
VERTICAL BEAM FORMING
USER 2
USER 1
HORIZONTAL BEAM FORMING
ACTIVE ANTENNAS
UMTS 900
19 VODAFONE C3 CONFIDENTIAL
DL and UL Short Term Key Features: CPC
•UE battery saving gains by allowing to turn off the transmitter and/or receiver
when there is no data
•DL and UL interference level reduction
•Benefit is maximised with users in the system performing little data transmission
as it happens in the Smartphone case
•Live tests show reduction of the UL load in around 2 dB of RSSI
•Trade off of 10ms latency increase
UL DTXDL DRX
DRX Pattern INACTIViTY
TIMER – RX ON RX OFF
time
HS‐SCCH and
E‐AGCH/RGCH
time
DPCCH DPCCH
UL DTX CYCLE
ACK/NACK CQI ACK/NACK ACK/NACK
time
CPC OFF ‐
DPCCH
time
20 VODAFONE C3 CONFIDENTIAL
DL and UL Short Term Key Features: HS‐FACH
•Handle more traffic on FACH
•Higher data rate compared to FACH
•More users per cell
•Higher capacity for chatty applications
•Reduce signalling
•Faster up switch FACH ‐> HSPA
•Less Power Consumption
HSPA
HS‐FACHFACH
CELL‐PCH
URA‐PCHIDLE
Data Rates
Power
Connected
21 VODAFONE C3 CONFIDENTIAL
The SmartPhone effect….
•Smartphones make many more PS calls, because of "Fast dormancy" handset
behaviour and "Heart Beat" of their applications. These UEs
are very dangerous
because they repeat and repeat connection attempts if they are not successful
•The normal sequence of radio congestion is as follows when the number of
HSUPA users rises, mainly 2ms UL ones–
RTWP rises exponentially; RTWP reaching ‐80dBm begins to degrade BTS sensitivity
–
UEs
use higher and higher power to reach the NodeB/RNC RTWP gets worse
–
UL RRC establishment messages do not arrive to RNC due to high noise UL RTWP
–
UEs
repeat RRC establishment Requests in a loop
–
FACH channel is saturated by high number of RRC Setup messages. RRC Setup messages
are queued and reach Timeout Collapse and “snow ball” effect
–
DL power saturates due to the lack of UL In‐Sync. UL Innerloop
does not converge
22 VODAFONE C3 CONFIDENTIAL
Example of Hot Spot: May Puerta
del Sol
Protest (Madrid)
• “Puerta
del Sol”
event ‐> May 17th – 22nd
• Big numbers–
Traffic:–35%
in case of voice and 50%
in case of data more traffic than New Years Eve peak–28%
more voice traffic than the Real Madrid Bernabeu
football match peak
–
Performance:–Accessibility problems at the beginning
of the event due to UL saturation–Dense network changes improved performance and allowed keeping Voice and Data calls
were in 3G
–Voice accessibility above 97%–Data accessibility above 80%
‐> In this case, it is almost transparent for the customer due
to the handset retries it automatically
–Dropped Call Rate
below 1%
23 VODAFONE C3 CONFIDENTIAL
Performance Summary in Puerta
del Sol
Voice Accessibility
Voice Erlangs
0%
100%
Voice Accessibility vs
Voice Traffic
0%
100%
Packet Accessibility
Data Traffic
Packet Accessibility vs
Data TrafficUplink Noise Level
Minimum UL Noise
Average UL Noise
24 VODAFONE C3 CONFIDENTIAL
Action Summary in Puerta
del Sol, Madrid
•3 Non‐barred Cell Carriers allowing device continuously to camp on best cell
• 15 code with 64QAM HSPA+ capability with 2ms HSUPA
•Over 1000 Channel Element base band capacity per site (for the UL)
•Fast Dormancy with Cell/URA PCH
•Remote Radio Units with 80W power amplifiers
•An Edge based 2G network with Coordinated paging and protected against RACH
storms
25 VODAFONE C3 CONFIDENTIAL
Conclusion
•Philosophy and methodology change in terms of network dimensioning due to
smartphone
introduction
•Multi‐RAB CS + PS service more and more important voice and data must be shared, no more need to protect data in dedicated carrier
•Average and peak throughput necessary but mainly reliable fast connection. Multi
Carrier for the short/medium term, MIMO for the long term
•Main target to reduce UL interference level by means of interference cancellation, new features (CPC and HS‐FACH) and network parameter tuning
•Fast dormancy feature critical to avoid too many reestablishment
from idle
26 VODAFONE CONFIDENTIAL 13 June 2011
THANK YOU
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