mass events
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mass events...
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Nokia Networks
Nokia Solutions for Mass Events
Nokia Portfolio Description Paper Nokia Solutions for Mass Events
Contents
Introduction
3
Trac Proles in Mass Events
4
LTE Requirements
5
Cell Grid Densication
7
Small Cells
8
HSPA+ Enhancements for mass events
10
Smart Wi-Fi Capacity
14
Summary
15
Innovation is happening right now at Nokia Many of the innovations from previous years described in this document are still relevant today and have been developed to support the optimization of mobile broadband networks and services. Looking ahead, Nokia will continue to focus on innovation and we will be updating this document to reect the latest developments.
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Introduction The popularity of smartphones creates a huge requirement for network capacity at mass events in stadiums housing up to 100,000 people or across larger outdoor events with up to a million or more participants. These large crowds of people use smartphones to share high denition pictures and video clips, and download vast amounts of information. This creates unusual trac proles, with higher uplink trac and more frequent packet transmission. Planning for these events must consider the uplink capacity and control plane dimensioning. Network RF planning in large open areas creates further challenges in the form of inter-cell interference. At the Korean Busan Fireworks festival in 2014, for example, over 552 GB of downlink and 338 GB of uplink trac data was transmitted over the Nokia Networks mobile broadband network during the peak hour, reaching a density of 570 users per cell and achieving data and voice call success rates of over 99.4%. This was the third consecutive year that an operator running on Nokia’s mobile network delivered best performance with the highest throughputs at this mass event, which attracts 1.5 million people to a 1.2 km beach front every year. Recently, Nokia Networks has patented several innovations for stadiums, achieving average uplink throughput gains of 150% to 250% compared to traditional networks.
Fig. 1. Example mass events
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Best LTE network quality in Korea (autumn 2014) Superior performance and stability even under highest load Performance during event peak hour 99.48 % 99.4 % 522 GB 338 GB 570 UEs/cell
RRC set up success rate VoLTE success rate Downlink data volume
Highest LTE user density > >
1.5M people on 1.2 km beachfront Korea’s second largest city
75% 50%
Uplink data volume Active users/cell (max) > > >
Inter-frequency load balancing works Real time monitoring with Nokia Tra ffica Network preparation and event execution with Nokia professional services
Nokia LTE performs under the highest loads
25%
LTE subscribers/capita subscribers/capita Korea Korea LTE 0% 3Q2012 3Q2013 3Q2014
Fig. 2. At the Korean Busan Fireworks festival in 2014, over 552 GB of downlink and 338 GB of uplink trac data went over the Nokia Networks mobile broadband network during the peak hour
Trac Proles in Mass Events Trac proles in mobile networks are typically dominated by the downlink trac, which can be up to ten times greater than uplink trac volumes. Downlink trac is generated mainly by streaming trac from smartphones, laptops and tablets. However, during mass events, the trac prole can be radically dierent. High volumes of uplink data trac are created by users sharing pictures and video clips from the event, for example on their Facebook account. The uplink can even experience more trac than the downlink. Streaming is rarely used at mass events unless there are venue specic services, such as a replay video service to show goals or touchdowns. Figure 3 shows this potential asymmetry.
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Mass Events are Uplink Limited – Physical Resource Block (PRB) Usage Average UL PRB use rate hits 100% @ Peak Hour while DL remains at 3 0% Uplink e 100 g a 80 s u 60 B R P
UL peak hour: 100% PRB use rate
40 20 0
60 mins
Downlink e 100 g a 80 s u 60 B R P
DL peak hour: 30% PRB use rate
40 20 0
1
PRB = transmission bandwidth
02/02/2015
60 mins
© Nokia 2014
Fig. 3. Uplink vs. Downlink trac share during a mass-event peak hour
LTE Requirements Long Term Evolution (LTE) is inherently well suited for bursty transmission of small packets generated by smartphones. Extreme conditions such as hot spots and mass events challenge the processing capacity of the control plane, as well as stretching Random Access Channel (RACH) capacity and increasing inter-cell interference. Figure 4 shows an example live network with highly loaded LTE base stations. The network experiences over two million Radio Resource Control (RRC) setup attempts per hour over 502 cells, which is 300% more than on a normal day. The RRC completion success rate remained very stable over the entire event day. 10th Busan Fireworks Festival (October 2014) Key Performance Indicators Number of RRC Setup Atts
Compl RACH stp SR LTE_1056D
RRC setup success rate 2,500,000
100 90
2,000,000
80
1,500,000
70
1,000,000
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50
0 0 0 0 0 : 0 : 0 : 0 1 2 0 0 0
0 0 0 0 : 0 : 0 : 3 4 5 0 0 0
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0 0 0 0 : 0 : 0 : 9 0 1 0 1 1
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0 0 0 0 : 0 : 0 : 5 6 7 1 1 1
0 0 0 0 : 0 : 0 : 8 9 0 1 1 2
0 0 0 0 : 0 : 0 : 1 2 3 2 2 2
Fig. 4. An example live network with highly loaded LTE base stations
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The key to network quality under extreme loads is Radio Resource Management (RRM) algorithms, which adapt to a variety of situations and trac conditions while enabling an ecient trade-o between fairness and eciency. RRM algorithms can be classied as single-cell and multi-cell algorithms. In LTE, the focus has been on single-cell algorithms such as frequency-selective scheduling with interference- and channelawareness, adaptive modulation and coding and uplink power control, which optimize the behavior of individual cells instead of considering the eects on neighboring cells. Single-cell algorithms continue to evolve with higher-order antenna and spatial diversity schemes such as single and multi-stream 4x4 Multiple Input Multiple output (MIMO) and 8x8 MIMO schemes. LTE-Advanced and beyond introduces multi-cell algorithms for baseband coordination between dierent cells to optimize overall network performance rather than that of individual cells. This shift is illustrated in 5.
Multi-Cell Coordination Cell Ck
LTE:
LTE-Advanced:
Cell C3
Optimize Individual Cells
B(C3;Hi)
Cell C2
C2
Optimize across Multiple Cells
Cell Ci
B(C2;Hi)
B(C1;Hi)
Cell C1
C1
Fig. 5. Shift from single-cell RRM optimization to optimization across multiple cells Multi-cell coordination techniques include various forms of CoMP (Coordinated Multi-Point transmission) such as Coordinated Scheduling, Dynamic Point Selection and Uplink Joint Reception. Due to strict latency requirements, baseband centralization / hoteling is recommended to get the best performance from multi-cell coordination algorithms. Transmission requirements are also typically higher, often calling for dedicated dark bers between inter-connected baseband units and RF units connected to them.
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Cell Grid Densication For mass events, the greater the number of cells, the greater the capacity. Yet, these larger numbers of cells result in greater cell overlap, increasing interference and preventing the deployment of the desired cell densities through fear of degrading performance. A recent Nokia innovation addresses uplink interference under extreme cell densities, a solution very suitable for fully packed stadiums and other popular mass-event gatherings within a dened area. The innovative Centralized RAN solution deploys inter-eNodeB UL CoMP, complemented by patented liquid cluster algorithms which virtualize cell boundaries. As a result, Nokia Centralized RAN allows cell grids to be as dense as desired, while eliminating performance penalties produced by interference. In fact, the more overlap and interference the cells create, the higher the UL trac gains. In parallel, device power headroom is increased, resulting in an extended terminal battery-life of up to 33%, a major benet to event attendees. This is a direct consequence of lower UE transmit power resulting from increased distribution and use of higher modulation and coding scheme (MCS) rates. Nokia Centralized RAN requires no special terminal capabilities and works with all existing R8 LTE terminals. It also runs on available Nokia macro base station gear. Centralized RAN load tests results Main Centralized RAN e ff ect in a nutshell 25 >
>
Centralized RAN promotes higher MCS rates resulting in higher t-put @ lower UE Tx power (higher UE power headroom) Centralized RAN eliminates interference eff ects/ limitations from the UE’s
20 S C15 M L U10
5
UE1
+
PHR gain 1.8dB
UE2
% 3 5 1 n i a g y c n e i c ffi E
CRAN ON CRAN OFF
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UE power Headroom [dB]
Fig. 6. Nokia Centralized RAN gains in a live stadium environment in Finland with higher MCS rate distribution and an increased UE power, resulting in 153% UL eciency gains Due to the cell density required in mass events, cell sizes need to be small, leading to a micro cell environment suitable for low-power base stations and remote radio heads. Nokia Centralized RAN deploys low-power RRHs hosted by baseband units which are sited in the same location, often called centralized architecture or baseband hoteling. Nokia Centralized RAN can also be deployed to a Distributed Antenna System (DAS) which supports 2x2 MIMO.
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Small Cells Micro and pico base stations, also known as small cells, are well suited to meeting the need for high capacity. Although small in size, they provide high connectivity of up to hundreds of simultaneous users. Small cells cover both outdoor and indoor public space as well as enterprise oce buildings. Femto access points oer low capacity and are better suited for residential use. They often lack carrier-grade characteristics and are less suited for Heterogeneous Networks, which call for seamless interworking with an overlaying macro layer. Micro/Pico base stations should have the same features as macro base stations to ensure a consistent end user performance across dierent cells. This also allows network optimization and interference mitigation between macro and small cells. Their small size and light weight reduces site and infrastructure requirements, while decent connectivity makes them the right choice for catering for high capacity. Deployed typically at street level, small cell base stations need to be visually discrete to blend with their surroundings. Example small cell products are illustrated in the following gures: • Nokia Flexi Lite Base Station for WCDMA/HSPA (10L/10kg with total output power of 10W+10W, Figure 7) • Nokia Flexi Zone (outdoor) Micro/Pico BTS (5L/5kg/5W+5W, Figure 8) • Nokia Flexi Zone Indoor Pico BTS (2L/2kg, 250mW, Figure 9) • Nokia Flexi Metro Remote Radio Head (5L/5kg with output power of 5W+5W)
Fig. 7. Nokia Flexi Lite Base Station, high capacity WCDMA/HSPA Small Cell base station Page 8
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Fig. 8. Nokia Flexi Zone Micro/Pico BTS, high capacity LTE Small Cell base station
Fig. 9. Nokia Flexi Zone Indoor Pico BTS
Fig. 10. Nokia Flexi Metro Remote Radio Head, low power RRH As networks become denser, hot spots evolve into hot zones. This requires special attention to the number of S1 and X2 interfaces as well as signaling trac and handover management. Nokia Flexi Zone Controller enables smooth evolution of hot spots into hot zones, housing a cluster of dozens of Flexi Zone small cells connected to a local controller to achieve high capacity. The Flexi Zone Controller serves as an aggregation point of S1 and X2 interfaces. The Fexi Zone small cell cluster is seen as a single logical base station to the rest of the network, reducing signaling to the core network and optimizing handovers to the macro layer and other hot zones.
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Flexi Zone Controller
> Single S1 interface to MME and SGW > Single X2 to a Macro eNB from all Flexi Zone APs I a cluster > Intra Zone Inter Flexi Zone AP interfaces within a cluster are managed as intra-eNB interfaces and are not visible outside the cluster. > X2 interface between neighbor Flexi Zone Controller clusters
Flexi Zone Controller X2 Z1
MME M E - M 1 S
S-GW
S1-U
X2 X2 Flexi Zone AP Cluster Y
Flexi Zone AP Cluster X
Macro eNB Flexi Zone Controller
Fig. 11. Flexi Zone Controller serves as an aggregation point of S1 and X2 interfaces
HSPA+ Enhancements for mass events HSPA+ is the most widespread mobile broadband technology, oering attractive end user data rates, high spectral eciency for data and good voice capacity. As HSPA+ continues to serve the largest subscriber segments over the coming years, mass events will need to cater for high HSPA trac, with special attention being paid to reducing interference and increasing uplink capacity. For the New Year’s celebration in 2013, Nokia helped a network covering a busy Asian city center to improve its performance. With 400,000 people gathered in a 1.2 km 2 area, 150 3G cells served 130, 000 HSPA users. Performance during the peak hour of the event
30.5%* higher Voice Traffic
DL Data Volume UL Data Volume Voice Traffic Cell Availability Call Setup Success Rate
32.7%* higher DL Data
27.9 GB 16.2 GB 306 Erl 100% 98.6%
Traffic
3500%* higher UL Data
Despite higher traffic, better KPI than in 2012 New Year’s Eve with another vendor’s equipment
Traffic
Fig. 12. For New Year 2013, Nokia helped a network covering a busy Asian city center to improve its performance.
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Among the features implemented by Nokia Professional Services were Mass Event Handler, Voice Call Prioritization, Multi-band Load Balancing and HSUPA with higher data rates to allow more uplink trac. Achievements included 100% cell availability and positive Key Performance Indicators, despite the high trac load. Reducing interference and improving uplink performance The greatest source of uplink interference is intra-cell high throughput HSUPA users. During an event, HSPA+ performance can be limited by interference from RACH and from Dedicated Physical Control Channel (DPCCH) in both the uplink and downlink. The transmission time of the user data is just a few milliseconds for small packet sizes, while DPCCH runs for a few seconds. In very high trac conditions, the Nokia Mass Event Handler (MEH) feature ensures ecient network operation, automatically tuning parameters for cell load control and reducing uplink interference. MEH has been successfully implemented in many world class mass events, resulting in excellent cell availability through its ability to adapt immediately to changes in trac. During mass events, HSPA Interference Cancellation allows more capacity and improved quality. Typically, 2ms TTI HSUPA users require a relatively high received power at the base station receiver, resulting in high interference to other users. The Nokia HSUPA Interference Cancellation feature eciently protects voice calls, R99 data and HSUPA 10ms TTI from this interference. The Enhanced HSUPA feature also cancels cross-interference between HSUPA 2ms TTI users. More users can be served up to the same eective noise rise after interference cancellation. This results in a capacity gain of approximately 60%, allowing 30% more HUSPA users per cell to be served. Trac in smartphone networks in general and particularly during mass events, is dominated by small to medium sized data packets. Transmission of a medium sized packet in HSPA network
High Speed Cell FACH enables more efficient utilization of air interface and allows up to 10 times more subscribers per cell compared to release 6 in cases where the traffic is dominated by small packets.
Fig. 13. Transmission of a medium sized packet in HSPA network
Ref: “HSPA+ Evolution to Release 12: Performance and Optimization” by Wiley, Chapter 4
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Using advanced features, the transmission of these packets can be optimized and air interface capacity used more eciently. Traditionally, when transmitting data for just a few milliseconds, devices stay in the Cell_DCH stage for several seconds to send control information. The Nokia Continuous Packet Connectivity feature stops this transmission after the user data is sent, allowing up to ve times more subscribers to be served by the cell. High Speed Cell FACH brings further improvements. It allows the handling of small and medium sized data packets on common shared high speed FACH channels, freeing additional capacity for users on HSPA channels where the actual data is transmitted. Nokia Networks’ live network test demonstrated 80% reduced signaling, 65% faster response time, up to 40% power savings in the 3G cellular modems* (contributing to longer battery life) and 20% faster browsing. (See “Enhanced Cell FACH increases operator revenue-generating potential” white paper with live network measurement results.) With 4-way Receive (Rx) diversity, uplink gains are enhanced still further. In this method, four receive paths of the BTS receive the same signal separately and combine them into a single, stronger signal. This can achieve a typical diversity gain of 3dB, allowing mobile devices to transmit 3dB less power, improving cell capacity by reducing interference. Dual Cell HSDPA is fairly common in today’s HSPA+ networks. In a similar way, Dual-Cell HSUPA combines two 5 MHz carriers in uplink and in concert with QPSK, enables peak rates up to 11.5 Mbps. The benet is fast load balancing between two carriers and increased throughput. In summary, the benets of features to address uplink capacity and interference are: • Mass Event Handler: improved subscriber access to services during mass events via dynamic adjustment of cell level parameters • Voice Call Prioritization: smooth voice service during high load • Continuous Packet Connectivity: more HSUPA users allowed in the cell due to discontinuous DPCCH transmission. • 4RX diversity: reduced interference and higher capacity due to signal reception over receive paths, 3dB lower terminal transmission power • Enhanced HSUPA interference cancellation: Up to 60% HSUPA throughput gain for high bit rate HSUPA users, achieved by cancelling cross-interference between high bit rate HSUPA (2ms TTI) users. Capacity gain: FDE 20%, PIC 60% with 30% more users per cell.
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“The Voice Call Prioritization in High Load Trac functionality has been piloted and subsequently mass deployed to the whole network where it was found to be very benecial for reducing blocking of voice trac during periods of high downlink load. Benets are seen in both the high-trac and mass-event situations. Only a small increase in data blocking resulted and this was acceptable given the voice improvement.” John Button, Radio Performance Design Manager Telefónica UK Limited • •
Dual Cell HSUPA boosts uplink to 11.5 Mbps (up to 100% data rate gain) combining two contiguous 5 MHz carriers in uplink Dynamic HSUPA BLER- Cell throughput up by 30% - Higher user and cell throughput in the uplink due to lower interference from other users 0.5 KB packet size
1 KB packet size
CPC
5x
4x
HS-RACH
5x
4x
4RX
2x
2x
Interference Cancellation
1.5x
1.5x
Total
75x
50x
Fig. 14. Increased Uplink capacity when using Nokia Networks’ solution for minimizing uplink interference Combining these features yields a huge improvement in uplink capacity for the transmission of small packets. Figure 14 shows that the capacity can be enhanced by 50 to 75 times. The main solutions used to minimize downlink interference are: • Fractional DPCH (F-DPCH) which removes the need for any Release 99 channel, avoiding downlink DPCCH • Mass Event Handler (MEH) which allows more power to be used for Release 99 channels as required, avoiding repetitive attempts and rejections for Release 99 high priority services such as voice.
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Operator A Voice and Data Overall Call Success theSuccess Event Park r A Voice andRate Data(OCSR) OverallinCall Rate (OCSR) in the O during the Olympics Event Start Olymp Event End 99.00%
e t a R s e e c u S l l a C l l a r e v O %
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>
Operator A performance levels maintained throughout the world class sports event in the UK
>
Voice performance close to already high ‘normal’ operational levels
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Data performance better than ‘normal’ operational levels
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Data OCSR Av Ntw Voice OCSR Av Ntw Data OCSR
Fig. 15. Nokia Networks secures awless performance during a world class sports event in UK, summer 2012 :
Excellent mobile service was maintained throughout the event including during the main ceremonies with signicantly higher trac and with better KPIs. Nokia Networks advanced RAN features such as MBLB (Multi Band Load Balancing) and Mass Event Handler allowed management of the trac across dierent bands and fast adaptation to load conditions.
Smart Wi-Fi Capacity Wi-Fi is used increasingly as a cost-eective means o-loading trac from conventional mobile networks. A n standard feature in nearly all smartphones and tablets, it allows mass event organizers to use unlicensed spectrum to improve the user-experience as well as oer venue-specic applications. The overwhelming number of users and business critical applications, like ticketing, can introduce a signicant stress on the available Wi-Fi network, requiring careful Wi-Fi network planning. Use of the 5 GHz band provides wider frequency spectrum and more bandwidth, as well as a higher number of available channels, allowing more Access Points (APs) to be deployed to meet the capacity demand without causing interference. The 2.4 GHz band will also need to be supported and because the band has three non-overlapping channels (1, 6, 11), reusing those channels is the primary alternative. As most devices at a mass event are smartphones supporting 3G/ LTE and Wi-Fi access, the use of all available networks should be considered in order to achieve the best overall experience. Page 14
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The recently launched Nokia Smart Wi-Fi is an end-to-end solution for building, optimizing and controlling Wi-Fi networks. The solution integrates mobile and Wi-Fi networks to give a seamless experience by supporting 3G-like usability and security for Wi-Fi access and harmonizing trac handling across mobile and Wi-Fi networks.In addition, Smart Wi-Fi balances trac across available mobile and Wi-Fi networks by controlling when and where user devices use these networks, based on the operator’s business strategy. Nokia Smart WiFi Solution Faster data speeds
By 2016 over 90% of wireless traffic will be data **
60-70% of traffic estimated indoors *
How to manage user experience & network utilization
3G-like Wi-Fi usability and security High performance indoor connections Increased customer satisfaction
Solution
Control user experience over Wi-Fi access Mobile core Operator Services
internet
* ABI Research
Retain position in traffic value chain Harmonized traffic handling with uni fied core for mobile and Wi-Fi
InternetS ervices
** Analysys Mason r
Fig. 16. Nokia Smart Wi-Fi solution turns Wi-Fi networks into seamless extensions of the mobile network
Summary Mass events place high demands on mobile networks: a large number of users in a small area, the dominance of uplink trac and the high frequency of transmitted small packets combined with challenging RF planning. Performance under such conditions calls for a dense grid of cells. The greater the number of cells, the better the capacity. Multicell coordination algorithms are required to ensure that neighbouring cells have minimum eect on each other. Nokia Networks radio networks have achieved excellent performance in mass events. The innovative Centralized RAN solution deploys inter– eNodeB Uplink CoMP functionality with Liquid Cell algorithms, which convert neighbouring cell interference into useful trac signals and provide uplink gains of up to 250% on average. Micro and pico base stations can be used to provide high capacities in hot spots with a simple installation and can be enhanced still further to Zone deployments as the number of small cells increases. Additionally, cellular network capacity is complemented by Wi-Fi ooading with the introduction of reliably high Wi-Fi RF performance, combined with the integration of mobile and Wi-Fi networks for the best possible user experience.
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Further reading Enhanced Cell_FACH raises operator revenue generating potential
Abbreviations 3GPP CINR CPC DAS DPCCH eMBMS eRAB F-DPCH HSPA HS-FACH HS-RACH IC LTE MEH PRACH PUSCH RACH RAN RF RRC WLAN
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Third Generation Partnership Project Carrier to Interference Noise Ratio Continuous Packet Connectivity Distributed Antenna System Dedicated Physical Control Channel Enhanced Multimedia Broadcast Multicast Services EUTRAN Radio Access Bearers Fractional DPCH High Speed Packet Access High Speed Forward Access Channel High Speed RACH Interference Cancellation Long Term Evolution Mass Event Handler Physical layer Random Access Channel Physical Uplink Shared Channel Random Access Channel Radio Access Network Radio Frequency Radio Resource Control Wireless Local Area Network
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Condential Nokia is a registered trademark of Nokia Corporation. Other product and company names mentioned herein may be trademarks or trade names of their respective owners. Nokia
Nokia Solutions and Networks Oy P.O. Box 1 FI-02022 Finland Visiting address: Karaportti 3, ESPOO, Finland Switchboard +358 71 400 4000 Product code C401-01154-WP-201501-1-EN © Nokia Solutions and Networks 2015
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