© 3GPP 2009 Mobile World Congress, Barcelona, 19th February 2009Small Cells in 3GPP [email protected] 1
Matthew Baker
Chairman 3GPP TSG RAN WG1
Alcatel-Lucent
From Macro to Small Cells: From Macro to Small Cells: Enhancements for Small Cells in 3GPPEnhancements for Small Cells in 3GPP
Small Cells Summit 2013
London, UK
© 3GPP 2009 Mobile World Congress, Barcelona, 19th February 2009Small Cells in 3GPP [email protected] 2
Mobile broadband data is exploding
Mobile broadband data is driving the need for network capacity
MOBILE DATA TRAFFIC WILL GROW >25 TIMES
BY 2016
TODAY
DATA is 90% of traffic
Source: Traffic Index, 2012 - Bell Labs Modeling
PB/MONTH
2016
2011
© 3GPP 2009 Mobile World Congress, Barcelona, 19th February 2009Small Cells in 3GPP [email protected] 3
How to address the demand?
More spectrum?
frequency
Interworking with other Radio Access Technologies
(e.g. WiFi)?
3GPP CN
Internet
LTE
WLAN
• Essential, but…
• Capacity only grows linearly with spectrum usage
Interworking with other Radio Access Technologies
(e.g. WiFi)?
• Useful, but…
• Uniformity of service provision
and of QoS are needed
• Spectrum for other RATs is
still finite
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Advanced multiple antenna configurations?
• 3D beamforming
Centralized BBU pool
Contro
ller
• CoMP
All give incremental gains in capacity, together with increasing complexity
•Massive MIMO
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More cells, smaller cells
Miniaturised base stations
Low power
Deployed wherever demand dictates
INCREASED PER-USER THROUGHPUT
REDUCED COST PER BIT
POTENTIAL FOR ORDERS-OF-MAGNITUDE
HIGHER CAPACITY
Small Cells
Small cells are the primary route to higher capacity
From to
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Small Cells in LTE
Release 8 Release 9 Release 10 Release 11 Release 12
Small cells have been supported by the LTE specifications since the beginning of LTE;
Frequency-domain inter-cell interference coordination (ICIC)
New base station classes introduced for local area and home deployments
Additional time-domain ICIC can be used in het nets of macro and isolated small cells
Pico
Further optimizations and enhancements for small cells, including dense small cell deployments
Macro
MacroPicos
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Scenarios for optimisation in Release 12
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Study of possible optimisations for specific
characteristics unique to small cell deployments
Small Cell Enhancements in Release 12
• Further enhancements to management of interference conditions
• Especially between small cells in dense clusters of small cells in hotzones
– Opportunities for traditional cell planning may be limited when large numbers of
small cells are situated according to traffic patterns
– Existing cells cannot necessarily be moved when new cells are inserted
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• Techniques include:
– Frequency-domain coordination
– Time-domain coordination
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– Transmission power management
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– Switching on/off small cells
» Match capacity to load
» Reduce interference
» Save energy
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– Coordinated scheduling / coordinated beamforming
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3GPP supports coordination across standardised interfaces
Practical backhaul connectivity
• Since small cells will be deployed based on demand, backhaul connectivity typically has non-negligible latency
• Like existing techniques, any new techniques in Release 12 need to operate successfully in a distributed manner with realistic inter-cell latencies over standardised interfaces
• Centralised coordination usually cannot be assumed
5-35ms Wireless Backhaul
25-35msCable
15-60msDSL Access
2-30msFibre
Latency (One way)Non-ideal Backhaul
Technology
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Further radio optimisations may take
into account specific characteristics of
small cell environment
• User Equipment mobility is typically low
• Relatively long channel coherence time
• Impact on handover rate
• Low delay spread / frequency-selectivity
• Wide range of SINRs
• In isolated small cells, SINR may be high
• In dense small cell deployments,
SINR may be lower
– Multiple strong interferers
Study optimisation of traffic handling and handover based on UE speed
Study possibilities for overhead reduction
Study feasibility of higher-order modulation
Interference management techniques
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Small cell discovery
• Large numbers of small cells may create new challenges for UEs to detect the best small cells to be associated with
• Switching on/off of small cells for load balancing or interference management may necessitate new mechanisms for small cell discovery
Possibilities for dual connectivity
• Study any potential benefits of simultaneous connection to macro and small cells
Pico
Macro
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The way ahead
Small cells uniquely provide
the ability to meet the
demands of data traffic
growth
Large numbers of small
cells may be deployed
where demand dictates
3GPP specifications are
continuing to evolve to
optimise performance for
the specific characteristics
of widespread small cell
deployment