Transcript Motorola Validation Status Report

Transforming 3G radio Access
Architecture
Ionut BIBAC & Emmanuel DUJARDIN
Agenda
 Main Triggers for New Access Architecture
 Toward Flat Architecture: Issue and Limitation
 The 3M of beyond 3G: Multi-Carrier, Multi-Antenna (MiMo) and
Multi-Layer
 One Word on SDR…
 Conclusion
Main Triggers for Deploying New Access Architecture

Access to a larger (and variable) spectrum allocation
 Higher spectrum efficiency which implies:
 Reduction latency with a better QoS and user experience
 Variable channel BW and harmonized FDD/TDD enables greater flexibility to exploit
different band allocations.
 Spectrum reframing where we can take advantage of the flexible channel BW and/or better potential
use of TDD spectrum.

Optimized for flat architecture (should leave to lower cost network in the long term)
 Not burdened by need to support legacy terminals and protocols leads to optimized
spectrum efficiency and latency performance.
 Higher capacity per site should lead to lower cost/bit at high traffic levels.
 Capability to support new service and/or competition with other technologies that
requires the lower latency of LTE to achieve good/equivalent customer satisfaction.
Towards Flat Architecture
flat architecture
fewer layers of network elements (collapsed architectures)
fewer central bottlenecks
more any to any connectivity
drivers / expected benefits (to be confirmed)
costs: lot of small not redundant units cheaper than few central high capacity,
highly reliable network elements (including hosting costs)
performance: traffic go through fewer equipments, more direct routes => less
latency, jitter, better throughput
Examples:
LTE/EPC
HSPA flat architecture / I-HSPA
Direct Tunnel
femtocells
3G – LTE/EPC – HSPA Flat
PSTN
MSC
3G:
HLR
NB
RNC
LTE/EPC (3GPP R8):
SGSN
GGSN
MME
HLR
Serving
Gateway
eNB
PDN
Gateway
Data
Data
HSPA Flat Architecture (3GPP R8 option) / I-HSPA:
RNC
PSTN
MSC
HLR
NB/RNC
SGSN
GGSN
Data
Direct Tunnel - Femto
Direct Tunnel:
(3GPP R7)
NB
Direct Tunnel
+ HSPA Flat:
PSTN
MSC
HLR
SGSN
RNC
RNC
GGSN
Data
PSTN
MSC
HLR
SGSN
NB/RNC
GGSN
Femto (not standard
yet):
HNB=
~NB/RNC
FGW
Data
PSTN
MSC
HLR
SGSN
GGSN
Data
Issue and Limitations of Flat Architecture

data only (except femto*): if voice on circuit, feasibility and performance to
be checked (for example on I-HSPA):
About Femto: most issues are currently handled with a gateway/proxy that hides complexity
from CN…but not really flat..though collapsed

signalling: all mobility is managed at CN level => either CN correctly
designed to handle it (EPC?) or best fitted for slow moving users

Security:
any to any connectivity assumes IP transport network, could be 3rd party network or even
public internet
collapsing RNC functions into NB involves that radio ciphering is done in NB
direct connection to CN equipments (except femto*)

impact on existing equipments (configuration and interface): more network
nodes visible (except femto*)

interworking and interconnections to legacy architectures need to have a
centralized point of interconnection
The 3M of beyond 3G: Multi-Carrier
 OFDM basic principles
Carrier (e.g. 5 MHz) is subdivided into many narrower band sub-carriers with lower rates
User receives many sub carriers together to achieve higher rates
Designed to achieve low distortion on each sub-carrier due to radio reflections and adjacent sub-carriers
–5
MHz Bandwidth
–FFT
–Sub-carriers
–Guard
Intervals
–…
–Symbols
–Frequency
–…
–Time
The 3M of beyond 3G: Multi-Antenna (Mimo)
MIMO = Canal matriciel 
xi : Signaux émis
Yi : Signaux reçus
N canaux de' transmission parallèles
x1
y1
x2
y2
xN
yN
Problème du récepteur:
Retrouver signaux émis X
X = H-1 Y
Possible si H est inversible
Eléments hij décorrélés
Conditions les plus favorables:
Milieu très réflectif
Plutôt Indoor
The 3M of beyond 3G: Multi-Layer
One Word on SDR…

Software Defined Radio stands for a radio technology agnostic Hardware platform in
which some or all Radio and Baseband functionalities are controlled by Software.

Early GSM specifications, about filters and frequency blocking, are challenging.Some
demand for relaxation of the band.

Difficulty to precisely estimate today the necessary processing power for a later use,
towards LTE for instance and ultimately any other new usage.

Coexistence of technologies in same modules is not easy to manage.

Vendors are tied with their current chipset choices. Moving to fully SW defined platform
means initially full re-development of firmware. On the other hand they gain full
flexibility on future development.

Roadmaps shows no OSS evolution with SDR introduction. For instance, changing the
technology is done by deletion & recreation of cells, all of the earlier settings and
optimisations are lost. SDR cannot (yet) be considered as a dynamic configuration
enabler
Conclusion
 Operator benefits of the new air interface
 Access to larger (and variable) spectrum allocations
 Higher spectrum efficiency: lower cost per bit
 Reduced latency: better QoS ans user experience
 Reasons for migration
 Higher spectrum efficiencies can also be achieved by HSPA+ with lower migration cost
(assuming 5 MHz spectrum allocation)
 New spectrum allocations or re-farming may motivate migration (currently 20 MHz
allocations seem very unlikely but 10 MHz may be possible)
 E-UTRAN will be deployed together with evolved packet core (EPC)
 Air Interface evolution will continue
 IMT advanced seems far away for operators.
 Concurrent systems are in starting blocks so 3GPP also has to respond.