1. Remus Sepp Unrestricted
Scope
Starting from the current wireless industry
status quo, this paper outlines a list of
challenges envisaged to be met during the
transition period into a HetNet dominated
world.
This paper represents author’s personal views.
Remus Sepp Unrestricted

2. Remus Sepp Unrestricted
Current status
• Some of the current wireless industry trends:
• Traffic/revenue decoupling – price erosion;
• Hockey stick traffic curve stage 1 already passed in 2010-2011 (first stage of
significant step change in the data traffic generated by smart phones);
• Network mergers significant CAPEX/OPEX reductions reported by the
Industry pioneers will probably lead to a generalisation of this trend;
• Smart-phone effects more and more prevalent;
• New techniques & RATs: HSPA+, HSDPA Dual Carrier, EGPRS2+, MIMO, LTE,
small cells, femto cells, wifi, etc. all add pressure onto the Operator, both in
OPEX and CAPEX;
• Forecasted up-scaling factors: 25…100 times the traffic we see today clearly
beyond the capability of the present day’s networks;
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3. Remus Sepp Unrestricted
Things to come change!!!
• “Mega” increase in the traffic generating devices numbers and diversity;
• Streaming traffic (2nd knee in the traffic curve ???);
• “Internet zero” (3rd knee effect ???);
• “Packet voice” to replace CS pretty soon (couple of years);
• QoS possible to be rolled across RAN and in tight integration with Core;
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4. Remus Sepp Unrestricted
The Capacity cycle
1..2 years
2010…2012 2013…2015
8 months
6 months
2017 ….
Inflexion point generated
by new “step change”
capacity solution
reduction in slope
Capacity Cycle
Starts when the Operator identifies
the need for a step-change capacity
solution
CAPACITY CYCLE 2
Ends when a critical mass (40% for
example) of the nodes are migrated
onto the new solution
CAPACITY CYCLE 1

5. Remus Sepp Unrestricted
The fuzzy “critical point” concept
1..2 years
2010…2012 2013…2015
8 months
6 months
2017 ….
Capacity Cycle
Capacity operational
curve
“Critical point” curve
How close
can they
be???
Usually the trends
and solutions are
common for the
industry
Let’s define the “Critical point” curve as the region beyond which the operator will get in
extended areas of congestion (>30% sites in >30% congestion) (Radio data or signalling);
30-30 curve
COLISSION
What is the meaning of collision? How long it takes to get critical?

6. Remus Sepp Unrestricted
“Capacity Cycle” dissected
CAPACITY CYCLE
BAU capacity
management process
Cells in capacity
problems
Critical
number
exceeded
+
Traffic
forecasting
DETECTION PHASE DESIGN PHASE ROLLOUT PHASE
•Features identification;
•KPIs identification;
•Actual Design;
•Trials;
•Validation;
•Areas identification;
•Budget approval;
•Programme setup;
•Actual rollout
Currently around
8 months to 1 year
Currently around
6 months
Currently around
1 year to achieve
the critical mass
Currently around
8 months to 1 year
Total practical duration can be
11/2 to 2 years

7. Remus Sepp Unrestricted
An exercise of imagination
Let’s consider a network of 10k sites, 2G, 3G, HSPA+ sites in operation today;
Also, let’s consider that this network will follow the stages below:
Stage A: 1..3 years from now
LTE half way on the maturity curve;
in the order of 10 small cells per macro cell 100k nodes to manage!!!
Stage B: 2…5 years from now
LTE mature;
30 femtos per site on average
The order of nodes to be managed scales up into 50k 500k nodes!!!
Stage C: 3…7 years from now
100…200 femtos per site, tight integration with wifi 1…2 millions nodes!!!

8. Remus Sepp Unrestricted
Our network’s evolution in this imaginary world:
If the operator in our imaginary example is today at the beginning of Stage A:
2 years
Capacity Cycle
Under such a scenario we can easily envisage some challenges:
• by mid 2014 this operator will have to manage
•A multi-carrier (2...4 carriers) 3G/HSPA+ network 10k nodes;
•An LTE network with enough traffic “on the plate” 6..7k nodes;
•A design for the Femto cells that takes into account all 3 RATs
(2G/3G/HSPA/LTE)
2012 2013 2014 2015 2016 2017 2018
Stage A
Small cells
Stage B
Femto cells –
initial phase
1 1/2
years
Stage C
Femto cells –
large scale
LTE maturity curve
400k
nodes
10k
nodes
100k
nodes
1..2 M
nodes

9. Remus Sepp Unrestricted
Challenges
• Such an up-scaling from 10k to 2M nodes in 4 years will
create extremely interesting questions about:
1. Traffic forecasting process:
2. BAU Capacity Management;
3. Performance Management process;
4. Design process;
Two main questions:
• What is the complexity of each of the above mentioned processes?
• Are there any hidden factors to be considered that can change this
complexity?
O(N) = ?
Network
nodes

10. Remus Sepp Unrestricted
Challenges in traffic forecasting
1. Even today is not easy to forecast a shared
2G/3G/HSPA network;
Better numerical forecasting algorithms to support scalability;
2. Coverage calculations enabler for a good forecast;
New propagation models will be necessary for Small Cells and/or Indoor solutions; also better
algorithms needed to pin-point the hot-spots;
3. More and more traffic layers are being rolled out;
New traffic steering modelling will be necessary to enable reliable outputs;
4. The Radio forecast figures will need to be aggregated
into RAN and core figures
The forecasting tools will need to consider an additional domain, the geography of nodes.

11. Remus Sepp Unrestricted
Impact on the BAU Capacity Monitoring
and the Performance Management
1. Every new technology produces substantial amount of new KPIs
A new set of KPIs can be currently reliably implemented in 1...3 months;
2. Increase from 10k nodes to 1M nodes reported/processed daily;
Additional IT budget needed;
3. Aggregation rules for the Capacity KPIs into a meaningful
correspondence (user perception KPIs)
Additional Radio Drive testing budget needed;

12. Remus Sepp Unrestricted
Challenges on the Design
1. The whole set of questions attached to the specific
technology:
LTE capacity limits / degraded service triggers;
Small cells optimum location / economical feasibility /
performance management (indoor testing);
Femto supervise quality for large scale deployment;
2. Consider the mobility / traffic steering between all
layers: this seems complex even if ANR/ANDSF
features are implemented;

13. Remus Sepp Unrestricted
Conclusions
•Wake up early
Today is the best moment to start thinking on these aspects
•Think twice
Take into account future dependencies to maximise design scalability
Remus Sepp Unrestricted