Download LTE-NX Common-control Plane Concept

“From always available
to always optimized”
Towards 5G – 5GrEEn system design
Dr. Pål Frenger, Ericsson Research
Outline
› General 5G introduction
› 5GREEN common control plane
– P. Frenger, M. Olsson, and E. Eriksson, “A Clean Slate Radio Network Designed for Maximum Energy
Performance” to be presented at PIMRC 2014
Ericsson Confidential | 2014-06-17 | Page 2
The networked society
The foundation of
mobile telephony
Mobile telephony
for everyone
The foundation of
mobile broadband
The evolution of
mobile broadband
The Networked
Society
~1980
~1990
~2000
~2010
~2020
Non-limiting access to information and sharing of data
anywhere and anytime for anyone and anything
Ericsson Confidential | 2014-06-17 | Page 3
Key Challenges
Massive growth in
Traffic Volume
Massive growth in
Wide range of
Connected Devices
Requirements &
Characteristics
Affordable and sustainable
Ericsson Confidential | 2014-06-17 | Page 4
•
Data rates
•
Latency
•
Reliability
•
Energy performance
•
Cost
•
.....
5G Spectrum – LTE compatibility
› Massive deployment of LTE devices in lower bands in 2020
› Introducing new incompatible RAT  loss of capacity and service level for
legacy devices
 Allow for LTE compatibility in lower bands
5G “mm-wave” access
5G “cellular” access
(lower-complexity design, short-range)
(higher performance, wider-area coverage)
3 GHz
LTE compatibility
Ericsson Confidential | 2014-06-17 | Page 5
10 GHz
30 GHz
100 GHz
P. Frenger, M. Olsson, and E. Eriksson, “A Clean Slate Radio Network Designed for Maximum
Energy Performance” to be presented at PIMRC 2014
5green Common-Control Plane
› What: Separate dedicated functionality from common system functionality
› Why:
– To fully enable usage of advanced (e.g. massive-MIMO) antenna systems
– To significantly enhance network energy performance
– Scalability, peak performance, forward compatibility
› Properties:
– Ultra-lean
– Static
– Stand-alone
Ericsson Confidential | 2014-06-17 | Page 7
Empty LTE Rel-8 sub-frame
How can we
BF the white
resources by
20 dB without
affecting any
of the colored
resources?
› Mandatory transmission of SIBs (in SF5) not shown
Ericsson Confidential | 2014-06-17 | Page 8
”To fully enable usage of
advanced antenna systems”
› A cell can never change shape
– RAS, antenna tilt, SON-load balancing, etc
› Massive MIMO beamforming gain  M / K
– 400 Tx antenna can give  26 dB beamforming gain
› For non-co-located antennas the path-gain difference can be >> 30 dB
– Near-far effect in UEs
Ericsson Confidential | 2014-06-17 | Page 9
”To significantly enhance
network energy performance”
Energy consumption for a typical European country-wide LTE network
– Scenario 1: “the most relevant traffic scenario for 2015”
– Scenario 2: “an upper bound on the anticipated traffic for 2015”
– Scenario 3: “an extremity for very high data usage in future networks”
Sub-frame Utilization
Energy Consumption Load Depencence
110
95%
95%
100
0.5
90%
90%
1.4%
81%
81%
80
1.4%
Area Power [kW/km ]
2]
Area Power [kW/km
2
Empty sub-frame ratio [%]
Empty sub-frame ratio [%]
90
Fixed Energy
Dynamic Energy
70
60
50
40
30
20
2.9%
2.9%
7.4%
7.4%
0.4
0.3
0.2
0.1
10
0
No traffic
traffic
No
Ericsson Confidential | 2014-06-17 | Page 10
Scenario11
Scenario
Scenario22
Scenario
Scenario 33
Scenario
0
No traffic
No
traffic
Scenario 11
Scenario
Scenario 22
Scenario
Scenario 33
Scenario
”Scalability, peak performance,
forward compatibility”
› Scalability:
– No need to add more common-signals when densifying networks
– We want to densify only the data plane and not the common-control plane
› Peak Performance:
– User performance gains of up to 350% was reported in the 3GPP NCT studies (R1-133399)
– Low traffic  interference is dominated by CRS-based signals  SINR is never super-high
› Forward compatibility:
– Best Feature of Rel-8 is the ”MBSFN sub-frames”
– Backhaul, Energy savings, Comp, Multi-hop relaying, etc.
Ericsson Confidential | 2014-06-17 | Page 11
5green C-CP Functionality
› Random access, including distribution of access information
› Paging, including passive mode mobility and location area update
› Positioning and localization
› Time and date provisioning
Ericsson Confidential | 2014-06-17 | Page 12
Random access and
Access information
distribution
Minimize broadcast
› Spectral efficiency significantly better with unicast compared to broadcast
› Only information related to initial access is broadcasted
– RACH: power, contention, physical resource, response channel
– Access restrictions: PLMN id, CSG
– Routing area
Common
System Information
(e.g. multi-RAT lists)
Access Information
Node Specific
System Information
(e.g. TM support, CRS configuration)
Ericsson Confidential | 2014-06-17 | Page 14
Communicated after initial system access
Communicated after initial node access
access information Table
› Access information tables transmitted with long periodicity (e.g. up to 10.24 s)
› Provide initial access related parameters for one or multiple areas
– Macro cells may transmit access information related to small cells
– Enhanced mobility by providing access information related to adjacent areas
› Mapping to table entry using a System signature transmissions more often
in time and space (100 ms)
frequency
Access
information
tables
Access
information
tables
System
Signature
Positioning RS
(every 500 ms)
time
Ericsson Confidential | 2014-06-17 | Page 15
System
Signature
Signature Sequences
› Nodes transmit a “system signature sequence”
– Similar to an LTE synchronization signal (e.g. 9 bits)
– Transmitted every 100 ms
– Does not need to be node specific
› Received index used for
– Deriving access information from the table
– UE Passive mode area update
› Received power used for
– Layer selection
– Open-loop power control
› Received timing used for
– PRACH transmission timing
– Paging window
Ericsson Confidential | 2014-06-17 | Page 16
Nodes transmitting SSS15
Nodes transmitting SSS3
Non node-specific RACH
› RACH does not have to be “node specific”
– Reduces amount of system information
– Allows for efficient small cell sleep and DTX
– Several nodes may use the same RACH configuration
› Consequences:
– Self-contained random access response (carrying its own pilot and sync)
› The UE may receive multiple random-access responses (RAR)
› Locally unique node ID used to derive locally unique RAR
– Handling of multiple RAR
› Inter node coordination
› “Contention resolution” / RAR selection in UE
Ericsson Confidential | 2014-06-17 | Page 17
RAR
Coordination
Paging and
passive mode
Mobility
Separate Active and
Passive mode mobility
› Passive mode mobility (or ”idle mode”):
– Paging, Random Access, and Positioning
– Defines system coverage
– Based on system signature sequences
› Active mode mobility
– Handover of active sessions between nodes
– UE speciffic mobility procedure and requirements
– Using additional, explicitly configured, mobility
referencer signals
Ericsson Confidential | 2014-06-17 | Page 19
Paging
”Paging area”
› Self contained messages
– Including synch and demod-RS
– Some synch channels may be shared between multiple UEs
› Paging cycle up to 24 hours
– Timing derived from SI and system signatures
”System-signature area”
› Paging may be transmitted over smaller area than the system-signature area
Ericsson Confidential | 2014-06-17 | Page 20
Example Use-cases
Legacy assisted operation
Forward compatibility
Legacy Assisted operation
› Access information table may be provided by LTE
– In MBSFN sub-frames; or
– as an MBMS service;
– as a new SIB
100 ms
5GREEN:
frequency
LTE Rel-8:
10.24 s
time
Ericsson Confidential | 2014-06-17 | Page 22
Forward compatibility
› The data-delated parts of PHY are contained inside a configured radio resource:
–
–
–
–
–
–
–
–
–
Tactile, ultra low latency
Low cost MTC
Ultra reliable
Extreeme MBB
Cirquit-switched
Backhaul
Public safety
D2D
...
Recipe for failure:
“Design for the union of all
5G requirements”
› Several different physical layers can be active in paralell
– Future post-5G-releases will define new physical layers
– All PHYs utilize only configured radio resources
Ericsson Confidential | 2014-06-17 | Page 23
Performance
Evaluations
Area power comparison
4
› LTE Rel-8 (Reference scenario):
› 5GREEN system:
– Access information table: 200 bits transmitted as 2 ms
bursts every 10 seconds
– System signature: 0.7 ms every 100 ms
› EARTH 2012 power models (macro and micro)
3.5
Area power consumption [kW/km 2]
– Heterogeneous network, Macro ISD = 500 m
– 3 micro cells per macro cell
3
2.5
2
1.5
1
0
Ericsson Confidential | 2014-06-17 | Page 25
-88%
0.5
LTE Rel8
5GREEN
Impact on longer sleep mode
P’sleep = Psleep / sleep
› 95% reduction possible if sleep power can
be reduced 3.5 times
35
Area Power Gain relative LTE-Rel-8
› Assume longer sleep mode enables lower
sleep power consumption
30
25
20
15
10
5
0
1
Ericsson Confidential | 2014-06-17 | Page 26
2
3
4
5
 sleep
6
7
8
9
10
Summary
› Decouple system functionality from data functionality
› 5GREEN Common-Control Plane functions and proposed solutions
– Access information distribution: signature sequence and table look-up
– Random access procedure: non-node speciffic, multiple responses
– Paging: self contained message with synch and demod RS
– Passive mode mobility: loose requirements
– Positioning and localization: beacon support integrated from day 1
› Properties: Ultra-lean, Static & Stand-alone
› Energy reduction in the order of 90-95% relative LTE Rel-8
Ericsson Confidential | 2014-06-17 | Page 27