NIPs towards India’s 5G
M Vinod Kumar
Tejas Networks Ltd
Thesis
• India’s 5G requirement is different and
therefore we need to ensure that:
1. We have complete method for X2 for HetNet BTS
interoperation: Macro-Micro, Macro-Pico, MicroPico, BTS-RN
2. Relay Node is enhanced and used for reach, high
capacity and non-line-of-sight backhaul
3. System Information is relooked, improved and
also acquired quickly
Agenda
•
•
•
•
•
•
•
What is G?
India’s 5G requirement
HetNet
Relay Node
X2 interface
System Information
Summary
What is G?
• G-Generation of TechnoloG
– Not incremental
– Support future services – but service agnostic
•
•
•
•
•
1G-Analog
2G-Digital
3G-WCDMA
4G-OFDMA/SC-FDMA
5G- $5 p.m. in 5 years
Sample Telecom Network
Devices
And
Applications
Devices
And
Applications
Enable these devices to communicate at lowest cost and reliably with these devices.
Devices
Inside Home
Metro
“Ring
roads’
Home
Fiber or
Copper
Home
Fiber
Microwave
or fiber
Wireless
Access
Office
Office
Fiber or
Copper
LAN inside
Office
Devices
Inside Home
Cell Tower
(2G/3G/LTE)
Fiber
Microwave
or fiber
Access
Roads
Fiber or
Copper
Fiber
Cell Tower
(2G/3G/LTE)
Wireless
Access
National Highway System
(“National Core”)
Metro
“Ring
roads’
Optical Networks
Access Equipment
Fiber or
Copper
LAN inside
Office
Recap: Mobile Evolution
Generation
Name
Data Rate / Speed
2G
GSM
10kbps (voice)
2G
CDMA
10kbps (voice)
2.5G
GPRS
~50kbps
2.75G
EDGE
~100kbps
3G
WCDMA/UMTS
384kbps
3G
CDMA 2000
384kbps
3.5G
HSDPA/HSUPA
5-30Mbps
3.5G
1xEVDO rev A,B,C 5-30Mbps
4G
LTE
100-200Mbps
4G
WiMAX
100-200Mbps
…Plus new enhancements to LTE
1000x
1000x
Mobile: The Future of Internet
Worldwide Access to Internet is growing and expected to
touch 3 Billion in 2015
Mobile Broadband showed strong growth of 87% Y-o-Y in
2008-2012 in developing countries; 100% in Asia-pacific
Evolution of Mobile Broadband
FASTER ACCESS
1 GBPS
2010
4G
56 MBPS
2000
1990
1980
HEAVIER CONTENT
Source: Sprint Traffic Analysis, 2013
3G
150 KBPS
2G
1G
SUPERIOR PROCESSORS
Source: Analysis Mason, 2014
LTE Deployment Worldwide
Source: LTE Maps
red marker per country for all operators to show commitments (trial, deploy, migrate, etc )
blue marker to show actual deployments.
©Tejas Networks Proprietary & Confidential
9
LTE: Broadband Wireless Access
350
LTE Base Station
300
250
200
Upload (MBPS)
150
Download (MBPS)
100
50
0
UMTS
HSPA HSPA+
LTE
LTE+
4G/LTE promises “DSL-like” performance on a wireless link – high throughput and
low latency (ideal for video)
LTE-advanced promises peak rates of 1 Gbps on the downlink using new antenna
technologies and modulation schemes
By 2017, ~70% of global spend on wireless equipment will be on LTE
• TD-LTE subscriber base in India to reach 67 million by 2017.
India’s 5G
• Scenario in India and other developing
countries is different than developed countries
• India already has dense Macro BTS
deployment which we should capitalize on
• ….So we have different 5G requirements
Global Vs Indian Scenario
Criteria
Global Scenario
Indian Scenario
Affordability
High
Low
BTS density
Spectrum cost
Fiber to villages
High speed mobility
Broadband penetration
Spectrum availability
Competition
Sparse
Medium
No/Copper
Yes
High
High
Medium
Dense
High
NOFN project
No
Poor
Low
Heavy
5G: METIS Objectives
• To provide a system concept that supports
– 1000 times higher mobile data volume per area
– 10 times to 100 times higher number of connected
devices
– 10 times to 100 times higher typical user data rate
– 10 times longer battery life for low power MMC
– 5 times reduced End-to-End latency
So Global Requirement is strictly
not applicable for India
Mobile Data Growth
12
10
APAC is almost 50% of Total
8
10x times
6
Total
APAC
4
2
0
2012
2013
2014
2015
2016
2017
EXABYTE growth (66% CAGR)
Source: Cisco VNI 2013
Demand Supply Analysis
• Assumptions
– 100 Mbps per sector, three sector per cell, LTE-Adv
– 250 GB per month, peak rate 2.5 Mbps
– Stat mux factor 10
• Mumbai City has 3,700 BTS and 5 mi households
– Demand-Supply ratio = 1
• India has 7,40,000 BTS and 250 mi households
– Demand-Supply ratio = 1
• Therefore with existing BTS density we can offer
– 250 mi house holds * 250 GB => 10 Exabytes p.m.
– 250 mi house holds * 2.5 Mbps => 1000 Exabytes p.m.
Observation
We can address the growth of traffic by:
“1000 times over next 5 years”
Target = 1000 Exabyte = 10 Power 21 Bytes
“This is all India wants from 5G: 5 Year Plan”
1000x times
Exabytes
One Exabyte
5G Requirements
• Primary means of broadband connectivity
• DSL-like
– Practically unlimited download
– Always available/ON or low service delay
• Low cost
– Avoid roll out cost
– Improve spectral efficiency with almost no new
spectrum
– Low power
5G Non- Requirements
• Avoid massive BTS roll outs
• Avoid new spectrum or more spectrum usage
– Because cost is transferred to end-customer
• No high speed solution
• No multiple devices because it is primary
connectivity
• No ultra long reach radio solution
– Village Panchayats have fiber- thanks to NOFN
– Villages primarily need voice connectivity
India wants from 5G:
• 4G did not factor Indian scenario
– It was designed for Elite
– It cannot solve our problem
• We want high spectral efficiency, low service
latency at affordable cost
• Primary broadband connectivity to 250 million
households at Rs. 250 p.m. for 250 GB at peak
rate of 2.5 Mbps (Stat mux 10x)
Vision:
$5/month “DSL-like” Mobile Broadband
$100 Laptop
$35 Tablet
Primary broadband connectivity to 250 million households at
the cost point of Rs. 250 p.m. for 250 GB at peak rate of 2.5
Mbps by 2017
Take Internet to Everyone!
~15 million fixed broadband connections
which covers a mere 5% of the homes
Huge demand potential in education and
entertainment; over 250 million homes to
be served in the coming years
Bulk of data connections still on 2.5G
Affordable Smartphones
Launch
18 M
30 M
33 M
2011
2012
2013
2014
Affordable smartphones but 3G continues
to languish in India; 4G yet to take off
Can we better 4G?
3
Slow Growth in G
Current 5G: More of the Same
Sr.
No.
Technology
Benefit
Comments
1
LTE Advanced
10x throughput of LTE
5x bandwidth, large-scale
MIMO
2
Full Duplex
Doubles capacity
On-going work
3
Higher frequency
band
Available, allows close packing
of antennae
Poor building penetration
4
Carrier Aggregation
Increases bandwidth
Throwing more bandwidth for
higher rate
5
MIMO
More layers, resiliency,
reach/coverage
Cannot use in low frequency
bands; more expensive
6
HetNet or Cell
Splitting
Better frequency reuse
Increases interference;
addresses penetration
problem
7
Spectral efficiency
More data using the same
bandwidth
More focus is needed here as
it enhances all of the above
Case Study: Mobile Networks in India
India has over 400,000 cell towers today
70%+ sites have grid outages in excess of
8 hours a day; 10% are completely offgrid
Huge dependency on diesel generator
sets for power backups
Cell Tower, DG Set, Grid
• India imports 3 billion liters of diesel annually to
support these cell sites
• CO2 emission exceeds 6 million metric tons a year
• Energy accounts for ~25% of network opex for
telcos
As mobile services expand to remote
rural areas, enormity of this problem
grows
Tejas Networks Proprietary
23
Energy Efficiency is a Major Challenge
RAN is a major bottleneck
Power Amplifier efficiency is
abysmal
Tejas Networks Proprietary
Source: R. Ganti, IIT-M, IAFOE 2014
24
Key India-specific Requirements
5G must factor in the Indian requirement for DSL-like connectivity:
Always ON, low latency, affordable cost
To minimize cost, 5G must avoid using many more BTS sites, or
much more spectrum, and focus on spectral efficiency
5G should allow virtual network operations enabling multiple
operators to use the same physical network infrastructure
India should grab the technology and standards leadership in 5G
as China did in 4G
5G must work well in Indian propagation characteristics—dense,
concrete buildings
5G infrastructure must be green—not just the CPEs or handsets—
since we lack good grid connectivity
Tejas Networks Proprietary
25
Relay Node enhancement
LTE-Advanced Architecture
• Show Rel-10 network with RN, Pico, MME, etc.
MME_UE
PDN_GW/internet
Relay Node
Pico
Evolved
Node B
MME_RN
Heterogeneous Network (HetNet)
• Macro – high power and roof-top antennas, gains
saturate as number increases due to ICI
• Pico – for further increase in network capacity, but
needs backhaul, has ICI at cell edge
• Femto – for connectivity within a buildings, but needs
DSL backhaul, has ICI at cell edge
• Relay Node – for further increase in network capacity
and coverage, it is non-line-of-sight, has no ICI, but
needs coordination with Donor eNode B
• There is no network element that is equivalent to Relay,
however need to implement RN configuration
messages
Relay Node
• India does not have high extensive DSL/Fiber
connectivity
• Our requirement is primary broadband and so
latency/delay is not of any concern: Chain of Relay will
solve problems
– Such scenario can be optimized at multiple levels and we
need to relook Relay again
• Besides, for large Indian operators, unlike other BTS,
Relay will not increase competition from small
(future?) mobile operators – it will keep the current
business intact
• Therefore Relay based deployment is more promising
Problem: The Loops
• UE requests MME_UE
• RN snoops the response and sends
request to MME_RN
MME_UE
PDN_GW/internet
Relay Node
Pico
Evolved
Node B
MME_RN
Cell Phone Activity
Cell Phone Activity
Agile BTS
• Notice that same region does not have activity all the time.
• So strategic relay node and macro BTS may be needed for:
– uncovering black-holed UE
– beamforming in a coordinated manner depending on the activity
• Interference can be drastically reduced if there are more
Relays than small cell BTS
X2 Definition
Network
MME / S-GW
MME / S-GW
S1
S1
S1
S1
X2
E-UTRAN
eNB
eNB
X2
X2
eNB
X2-AP
• There are three ways to get Radio Resource
messages
– X2-AP
– S1-AP
– RIM
• Out of this X2-AP is faster and required
X2-Interface Use Case
• CoMP
• SON
– Auto configuration
– Optimization
– Self healing
•
•
•
•
ICIC
Relay Node
Network Cost
SDN
Coordinated MultiPoint
• To improve cell edge throughput and improve
overall average cell througput
• Downlink
– Joint processing: many transmitters to one UE
either simultaneously or on time-share basis
– Coordinated Scheduling/beamforming
• Uplink
– Joint reception
– Coordinated Scheduling/beamforming
Self Organizing Networks
• Self-Configuring of X2 interface
– Discover neighbour relation (ANR)
• Self-optimizing
– Mobility load balancing
– Energy saving, e.g. by shutting down
– Handover failure optimization
• Self-healing
Software Defined Network
• Virtualization of eNodeB
• One slice is one eNodeB or cell
• Providing such a slice dynamically and on
demand needs such eNode B to interact with
other BTS over X2
Chain BTS without Backhaul
• Sometimes BTS are chained over microwave
backhaul
• In such scenario S1-AP messages for handover
from terminal BTS (small) to pen-ultimate BTS
(macro) will lead to double the bandwidth
consumption
Relay Node
• A Relay Node’s cell can experience interference
with neighbouring eNode B, even if the donor
eNode B does not experience such
interference
• This happens when RN is used for range
extension of the donor cell
• ICI can be reduced if RN coordinates with
neighbour BTS over X2
Inter Cell Interference Coordination
• Neighbouring eNodeBs coordinate their use of
resources to help minimize intercell
interference
– Avoiding same resource blocks
• This requires X2 signalling
• Particularly important when there are going to
be many small cells
Deployment Cost
• In HetNet, if small cells have to go to MME all
the time for SON then Core Network will be
overloaded by signaling messages and will
deteriorate the network utilization
• This will increase service latency given than
two eNode Bs (small and macro) are 1-2 km
compared to MME which is 100 km apart.
X2 Definition
• The 3GPP standard has provided guidelines for
the X2 interface
• We need to take these guidelines and define
these APIs (all functions and variables) with
more details so that they can be implemented
as such for quicker network deployment by
vendors and carriers/operators
• Operators can enjoy an efficient network on
day one!
System Information
System Information
• System Information is read by UE in RRC Idle
mode to acquire parameters necessary for
–
–
–
–
–
cell selection
cell re-selection
Paging
SI change
disaster notification, etc.
• System Information (SI) in an LTE system is divided
into a number of System Information Blocks (SIBs)
and Master Information Block (MIB)
System Information
• The MIB includes limited number of most essential and frequently
transmitted parameters to acquire other information from the cell
• SI is defined in 3GPP TS 36.300 & 36.331 as a Radio Resource
Control (RRC) message carrying a number of System Information
Blocks (SIBs) that have the same periodicity
• Each System Information Block (SIB) contains a set of related system
information parameters
• System Information Block Type1 (SIB1) is transmitted alone,
separately from other SI-messages
• SIBs other than SIB1 are carried in SI messages and mapping of
System Information Blocks to SI messages is flexibly configurable by
using scheduling Information parameters included in SIB1, with
restrictions that each SIB is contained only in a single SI message.
• Only SIBs having the same scheduling (periodicity) requirement can
be mapped to the same SI message.
Reading of System Information
1. Start with MIB
–
–
BCCH  BCH  PBCH
Downlink Channel Bandwidth, PHICH Config, SFN
2. Reading SIB1 after MIB
–
–
BCCH  DL-SCH  PDSCH
PLMN ID, TAC, cell selection parameters, Frequency Band, Cell
barring, Scheduling of other SIBs
3. Reading other SIB after SIB1
–
–
–
–
BCCH  DL-SCH  PDSCH
SIB2, SIB3, so on upto SIB19
Barring, RRC, Timers, MBSFN, etc.
SIB2 has RRC message called Modification Period Coefficient
Problem 1
•
•
•
•
•
The number of SI bits that can be transmitted in any subframe is limited
and the SI message should be transmitted in one subframe.
This limits the number of System Information Block (SIB) messages that can
be mapped to a single SI message.
This decreases the number of SIB messages that can be mapped to a single
SI message thereby delaying the acquisition of SI messages by UE, which as
a consequence increases the power consumption of UE.
There is another restriction in terms of ‘maximum bits that can be
transmitted over a single subframe’. This restriction is due to channel
condition, modulation and coding scheme, etc. This restriction requires
that an SI message formed of multiple SIBs need to be segmented; but,
there is no method defined for this segmentation.
Therefore we need to provide flexibility in mapping SIB messages to a
single SI message thereby providing opportunity for faster acquisition of SI
messages by User Equipment (UE), which as a consequence reduces the UE
power consumption.
Problem 2
•
•
•
•
•
Acquiring only modified system information is not possible. One needs to acquire all SI
In the event that modification of system information is desired, the network can undergo a
system information modification procedure by which all UEs communicating with the network
are informed of an impending change to the system information.
However, in conventional implementations, a wireless communication network conveys only a
generalized indicator of an upcoming change of system information to its respective served
UEs without providing any further information relating to the information to be changed. As a
result, UEs communicating with the network can in some cases be required to re-acquire all
system information at each modification regardless of the information to be affected by a
given modification. Such a requirement can, in turn, degrade UE and/or network performance
and power efficiency, an increase in UE implementation complexity, etc.
Normally, during System Information Modification procedure, the eNB transmits the modified
System Information in the corresponding modification period. The UE is informed through
Paging Procedure and/or SIB2 about the SI modification. But the UE does not know which SI
has got modified. The UE acquires the new system information immediately from the next SI
modification period. This procedure is inefficient since the UE will acquire all SI messages
irrespective of whether the SI message has got modified or not.
There is a need to relook at acquiring modified system information messages in a user
equipment.
Problem 3
• Transmission conflict between SI and SIB1 for window length of 1
ms and thereby restricting the number of SI that can be
transmitted in 1ms window
• In LTE, for system information window length of 1 millisecond, the
number of system information messages that can be transmitted is
limited. It is specified in the LTE system that other SIs are not
allowed to be transmitted in sub-frame #5 satisfying SFN % 2=0 in
order to avoid mixing SIB1 and other SIs on the same sub-frame.
Further uplink subframe and special subframe for which special
subframe configuration does not support PDSCH transmission and
MBSFN subframes block the transfer of system information
message.
• There is a need to overcome this problem so that transmitting
conflict between the SI and SIB1 and the associated delay can be
avoided.
Example of 1ms Window
SFN 0
SFN 1
SFN 0
SFN 1
Other problems
• Transmission and decoding of multiple SI in a
subframe
• Transmitting longer SI i.e. SI with many SIB of
same periodicity
• SIB for ultra low rate IoT/M2M devices like
water and electricity meters
– Requirement from organizations like BESCOM and
BWSSB
Summary
• NIP for India’s 5G
– Relay enhancements
– X2 definition development
– SI message enhancements
• Requesting Work Item on these NIPs for
deeper study. Most study has already gone
into these items at 3GPP. So requesting for
both SI and WI so that RNES WG can have
some WI to work for.
Thank you.
Questions?
Extras…
4G: IMT-Advanced
• Internet Protocol (IP) based network
• Interoperate with existing wireless standards
• A nominal data rate of 100 Mbit/s while the client physically moves
at high speeds relative to the station, and 1 Gbit/s while client and
station are in relatively fixed positions.
• Scalable channel bandwidth 5–20 MHz
• Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75
bit/s/Hz in the uplink
• System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink
and 2.25 bit/s/Hz/cell for indoor usage
• Seamless connectivity and global roaming across multiple networks
with smooth handovers
• Others….
http://en.wikipedia.org/wiki/IMT_Advanced
BTS Statistics in India
Calculations
Particulars
Value
Per cell rate (bps)
100,000,000
Sectors per cell
3
Peak data rate (bps)
2,500,000
Stat Mux
10
Cell rate to user rate
40
BTS in Mumbai
3,700
Households in Mumbai
5,000,000
BTS in India
740,000
Households in India
250,000,000
BTS in Mumbai can serve households
4,440,000
BTS in India can serve households
888,000,000
Supply is 1000 Exabytes
• 5.75 x 10^20 is approximated to 1000 x 10^18
• 1000 x 10^18=1000 Exabytes = 1 Zetabytes
Seconds per month
250 mi x 2.5 Mbps for 1 month
250 GB x 250 mi
100 Mbps x 3 sectors x 740000 BTS
740000 BTS x 100 Mbps x 3 sector x Stat mux 10
2592000
2.025E+20
6.25E+19
5.75424E+20
5.75424E+21