PS core network evolution in the MBB age
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By Ding Gan
Mobile broadband (MBB) development is raising the bar for core network
performance along a variety of dimensions, and Huawei is there to help with a
complete lineup of solutions that encompass any and all challenges and opportunities
an operator might face..
The last decade has seen explosive growth in both traffic and signaling, creating new
capacity and reliability requirements for the core network. We are currently seeing
vigorous LTE development and telcos’ shifting focus towards convergent multimedia
services that call for even more from packet-switched (PS) core networks if they are
to handle this avalanche of multimedia. For the next decade, as MBB applications
extend to new markets such as the enterprise and family markets, customization
requirements will accrue and thus continue driving PS core network evolution
towards a cloud-based platform with open network architecture.
Larger capacity, higher performance
In 2006, large-scale HSPA deployment catalyzed the mobile data service business,
while data card services and “all you can eat” packages spurred further traffic growth.
According to Huawei mLAB statistics, this period saw a doubling of annual traffic
growth for almost all telcos, with some increasing by up to seven fold. In 2008, as
smartphones started drawing oohs and ahhs from consumers, both data services and
signaling in general saw explosive growth that continues to this day.
Huawei is there to help with our Service GPRS Support Node (SGSN), which can
support 23 million concurrent users, with throughput per cabinet for the Gateway
GPRS Support Node (GGSN) reaching 900Gbps (sufficient for the network demands
of today). Moreover, Huawei’s SingleEPC PS core network solution enables
continuous capacity expansion, thanks to cloud-based platform enablement.
In addition to capacity, performance improvements are needed for the core network so
that it can weather signaling storms; each network element (NE) must be insulated
from overload breakdown. In theory, the system will crash if signal traffic is twice the
NE’s design limit, but real-world storm traffic can exceed it ten fold – not a tenable
position. But with SingleEPC, the protection design mechanism can withstand a
64-fold surge, ensuring operation in even the most extreme circumstances.
However, protection of NEs such as the home location register (HLR), radius server,
and mobile switching center (MSC) must account for the big picture. By detecting the
signal capacity and status for neighboring NEs, Huawei SingleEPC adjusts the
maximum signal load sent to neighboring nodes, ensuring reliability for the entire
network.
Multi-service handling
In the MBB age, telcos face being marginalized as dump pipe providers, means to an
end for smartphone users looking to access Internet and/or over-the-top (OTT)
services, even as OTT innovators gradually encroach on telcos’ territory and profit.
They must respond by diversifying their service lineups with new media.
Voice service
With the advent of LTE, telco voice services will also be based on IP, as they are with
the OTT players, but IP infrastructure is inherently less reliable, due to the IP
multimedia subsystem (IMS) and evolved packet core (EPC) network elements.
Huawei’s LTE voice solution, on the other hand, dynamically switches between
CSFB and VoLTE to select whichever is better for voice service, ensuring a
carrier-grade reliability of 99.999%.
As opposed to VoLTE, CSFB utilizes CS architecture for voice, and this requires
frequent switchover between LTE and UMTS/GSM, so the ensuing connection can be
a major hindrance to a good user experience. According to Huawei mLAB, the actual
delay can exceed 10 seconds if both the sender and receiver are connected to a
traditional UMTS or GSM network. Huawei Flash CSFB solution greatly reduces this
delay, reaching a level on par with a traditional CS network.
Video & web browsing services
As the bridge between CT and IT infrastructure, the PS core converges a massive
amount of CT data, while carrying abundant OTT services. This gives it a unique
position to handle multimedia services in the manner best suited to current network
status, by leveraging its privileged access to key assets, namely user, service, and
network data.
While web browsing is still the primary data service, video is becoming increasingly
popular. According to mLAB statistics, video traffic will account for over 60% of
mobile traffic overall by 2016. Improved resource utilization is clearly needed here if
operators wish to guarantee a superior user experience.
Huawei’s MSE (multi-service engine) solution is aimed squarely at optimizing both
video and web browsing. For the former, it incorporates intelligent rate adaptation that
dynamically adjust the downlink code rate as per terminal attributes such as screen
size and resolution, while intelligent cache technology can move hot content to the
local hard drive to accelerate visit speed and intelligent loading technology can
automatically identify the user’s current viewing progress and push content
accordingly to best conserve wireless network resources.
Open cloud-based architecture
As mentioned previously, smart devices and OTT services are continuously changing,
so network traffic patterns demand real-time flexibility in terms of resource allocation.
Open cloud-based architecture is indispensable to the PS core in this instance.
Cloud architecture
Cloud-based network architecture represents the ultimate in PS network resource
allocation. It divides the network into three layers – device, virtual, and application.
The device level is the bottom, and is modular and standardized (in terms of
capability). The virtual layer manages the device layer, keeping the modules in order
and allocating resources to the bottom for use by services, while the application layer
uses software to virtualize the logical NEs, such as the MME, SGSN, GGSN, service
gateway (S-GW), PDN gateway (P-GW), and radio network controller (RNC).
This architecture brings about three major benefits. First, the decoupling between the
device and application layers enables flexible expansion or reduction of capacity for
each single NE in the application layer, reducing the costs inherent to flexible
capacity on the wireless side, while board addition or subtraction at the device layer
does not affect the application layer, protecting the operational integrity of the system.
What’s more, decoupling simplifies the O&M process, reducing costs on a variety of
fronts.
Second, network reliability is greatly enhanced. Compared with backup programs at
the device level, real-time virtual machine migration, automatic node failure recovery,
and disaster recovery enhance network availability/recovery considerably. And finally,
centralization of network gear makes it much easier for telcos to share/open their
network via virtualization to MVNOs.
Openness
Telcos must work with OTT competitors when the circumstances dictate. In the
current MBB ecosystem, there are three types of third parties – Internet service
providers, smart device providers, and IT service providers; each has different core
capabilities and assets.
Telcos, on the other hand, have network capability as their key asset, and this includes
firsthand knowledge of network load, speed, user location, user attribute, service type,
and so on. All can be customized as different application platform interfaces (APIs)
and opened to other players in the industry chain, making for new business models.
With further ICT convergence, machine-to-machine (M2M) connections will carry
considerable weight in the future, offering new opportunities for telcos to venture into
new verticals.
Huawei’s SingleEPC solution is suited to these aforementioned PS core development
trends, enabling great network reliability and capacity, as well as optimized
multimedia services and improved network resource utilization, building a solid
foundation for finely-honed MBB operation.
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