moray rumney's presentation at emerging communication conference & awards 2009 europe
TRANSCRIPT
2 0 0 9 | W e s t e r g a s f a b r i e k | A m s t e r d a m | http://eComm.ec
LTE:
Long Term Employment
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Or
Less Than Expected?
Moray RumneyAgilent Technologies
© Copyright 2009 Agilent Technologies, Inc.
�
Opening thoughts
4G – Too little too soon?
Six concerns about the evolution of wireless:
1. Pursuit of high performance is not keeping up with demand
2. Growing complexity
3. Evidence of diminishing network quality
4. Market and supply chain fragmentation
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
4. Market and supply chain fragmentation
5. Growing costs
6. Immature market – confusion over role of value, price and cost
Inspired by:
Technology in the Recession: Less is Moore
http://www.economist.com/opinion/displaystory.cfm?story_id=12932356
Page 2
Predicting the next winning technologyOften the “best” doesn’t win
• Ethernet vs. Token ring
• 802.11b vs. HiperLAN
• Windows 3.1 vs. Unix
• Iridium vs. GSM
• Esperanto vs. English (or maybe Chinese...)
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
• Esperanto vs. English (or maybe Chinese...)
• Now it’s LTE vs. GSM, HSPA - and Wi-Fi
“Perfection is the enemy of the good”Gustave Flaubert
French Novelist 1821 - 1880
Page 3
What we would like in wireless…
Simplicity and economies of scale:
- One worldwide wireless standard for everything
- One air interface
- One frequency band
- One core network
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
- One application development framework
- And no IPR (that we don’t own…)
For 2G, GSM substantially achieved this in 1992
For 3G, UMTS tried to achieve this in 1999 but faltered
For 4G, what is the outlook - will LTE deliver?
Page 4
Attractive attributes of LTE
Based on OFDMA giving:
• Scalable bandwidths for deployment flexibility and high data
rates
• Suitable for use with MIMO
• Supports narrowband scheduling to take advantage of fading
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
• Potential for higher efficiency than CDMA at wide bandwidths
• Supports enhanced broadcast features (MBSFN)
• Support for in-channel relaying (backhaul)
Simpler low latency packet-only core network
Support for QoS (e.g. for VoIP)
Page 5
Planned Order
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 6
…and the space (spectrum) to deploy it
Note use of spacial diversity!
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 7
Denver
But what we have…
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 8
…is the legacy
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 9
5G 2G
3G
1G
Yuck!
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 10
4G
Heathrow
IS-136TDMA PDCGSM
IS-95Acdma
Wireless evolution 1990 - 2010
2G
Incre
asin
g e
ffic
ien
cy,
ban
dw
idth
an
d d
ata
rate
s
2.5G
3G
HSCSD iModeGPRSIS-95Bcdma
E-GPRSEDGE
IS-95Ccdma2000
W-CDMAFDD
W-CDMATDD
TD-SCDMALCR-TDD
802.11g
802.11a
802.11b
802.11n
802.11h
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Incre
asin
g e
ffic
ien
cy,
ban
dw
idth
an
d d
ata
rate
s
3.5G
3.9G
4G
LTE-Advanced Rel-10
802.16m
HSUPAFDD & TDD
1xEV-DORelease B
1xEV-DORelease A
1xEV-DORelease 0
HSDPAFDD & TDD
UMB LTERel-8
Edge Evolution HSPA+
802.16eMobile
WiMAXTM
802.16dFixed
WiMAXTM
WiBRO
Page 11
In 20 years of evolution why has so little
come off the plate?
Phases of Technology Adoption
1. StandardizationThe Committee
Room
2. RegulationThe Test House
3. PhysicsMaxwell’s
Place
4. CommerceThe Shopping
Mall
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Where engineers consume lots of
coffee while creating wireless law
Where products are put on trial to prove their conformance
Where electro-magnetic law determines if it actually works
Where commercial law determines whether anyone actually buys it
And then there was light…
Just because the industry invents a new standard does not mean success is guaranteed. What determines commercial success?
Page 12
Technology evolution - Audio
Over the last century, audio has evolved from wax through shellac, vinyl, metallic tape, to opto-mechanical discs and finally solid state silicon
At each new generation the user perceived benefits have been undeniable meaning earlier generations have largely been obsoleted.
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 13
Technology evolution – Cellular
Commercial Cellular phone technology started in the 70s with expensive bulky and heavy products moving through the first true “handsets” and onto GSM and CDMA
So is the added value of new generations slowing down?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 14
Performance - Which is the best car?
$2,500 $1,500,000
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 15
Answer: Both! It depends on the problem you are trying to solve
Page 15
Top end wireless is a bit like the top end automotive• It is undeniably real• But is it affordable?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
And once you have purchased it, where and how often can you really experience it?
Top Speed – 253 mph
1001 bhp
0 – 60 mph in 2.5 seconds
0 – 125 mph in 7.5 sec
0 – 250 mph in 16.7 sec
250 – 0 mph in 9.8 sec
At top speed, empties its fuel tank in 12 minutes!
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Price: $ 1,500,000 (plus tax!)
If your supercar commute to work looks like this then you will have paid for peak performance but
you will experience average or poor performance
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Quiz #1 - High speed vs. high capacity
At what average speed does the capacity (i.e.
cars per hour) of this road reach its peak?
10 mph ?
40 mph ?
70 mph ?
This is counter-intuitive: High speed drives down capacity!
In wireless, high data rates consume disproportionately more resources and provide less coverage for fewer users –
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
100 mph ?
1000 mph?
coverage for fewer users –overall capacity reduces.
Improving capacity through higher average speeds is plain hard work
In motoring terms, improving the average would require a whole new form of robotic control.
Page 19
So what really matters - Peak or Average?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 20
WoW! Now with predictive
results!
What is enabling the apparent exponential growth in wireless communications?
The capacity of a system to deliver services is defined by three
main factors:
• The bandwidth of the available radio spectrum – in MHz
• The efficient use of that spectrum – bits / second / hertz
• The number of cells – this equates to spectrum reuse
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Number of cells
Eff
icie
nc
y
Page 21
Growth to date dominated by increasing cell count
If we apply Cooper’s law over the last 50 years we are looking at a growth in wireless capacity of perhaps 1,000,000
Allocating this growth between the axes of capacity looks roughly like this:
1000
200010000
Growth has
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Gro
wth
fa
cto
r
1
10
100
1000
2025
Efficiency Spectrum No. of cells
Growth has
historically been
dominated by the
increase in the
number of cells
Page 22
Comparing wireless growth potential for the next decade
Gro
wth
po
ten
tia
l
10
100
100
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Gro
wth
po
ten
tia
l
1
32
Efficiency Spectrum No. of cells
Using current projections, the increase of cell numbers (spectrum
reuse) remains the dominant means of growing capacity
Page 23
Spectral Efficiency bits / sec / Hz
1
10
100
W-CDMA
HSDPA
1xEV-DO
LTE
802.16e
IS-95C
Growth in peak / average spectral efficiency by technology
Peak efficiency lies around this line
Average efficiency and hence capacitygrowth of deployed systems lags well behind and will level
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
0.01
0.1
1980 1985 1990 1995 2000 2005 2010 2015
Average efficiency Peak efficiency
AMPS
GSM
GPRS
EDGE
1xEV-DO(A)EGPRS2 1/3
W-CDMA (R99)EGPRS 4/12 (R99)
HSDPA (R7)HSDPA (R5)
LTE target
EGPRS 1/3 (R99)
off due to inter-cell interference
Peak efficiency drives
up air interface cost &complexity
You pay for the peak but experience the
average
Page 24
Projecting ahead shows the gap between average and peak rates in a loaded cell will grow to 90x
Data rates x 100000
Efficiency x 87Spectrum x 13
�1100x capacity 10000000
100000000
1000000000
Peak rates Average Efficiency Spectrum Capacity
Efficiency, spectrum and capacity are normalized to single-band GSM in 1992 83 users/cell occupying 25 MHz @ 9.6 kbps
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
A 90x gap will exist by 2015
10000
100000
1000000
1985 1990 1995 2000 2005 2010 2015
The average efficiency, spectrum and capacity plots are normalized
The outlook is that average efficiency and spectrum will fall further behind
peak rates
Page 25
And on a linear scale
500000000
600000000
700000000
800000000
900000000
1000000000
Peak rates Average Efficiency Spectrum Capacity
Macrocell reality lies
somewhere below this line
The capacity crunch
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
0
100000000
200000000
300000000
400000000
500000000
1985 1990 1995 2000 2005 2010 2015
below this line
Page 26
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 27
Setting performance expectations –
150 Mbps is your right!
Examples of growing complexity:Voice support
2G & 3G
• Single solution – circuit-switched services
3.9G/4G LTE
1. IMS – preferred 3GPP solution
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
1. IMS – preferred 3GPP solution
2. Circuit-Switched Fallback – preferred 3GPP alternative
3. VoLGA – UMA/GAN for LTE
4. Fast Track voice over LTE (NSN – SIP-based)
5. Proprietary solutions (e.g. Skype)
Choice creates unwanted interworking complexity
Page 28
IMT Band explosion
Operating Band
Uplink (UL) operating bandBS receive/UE transmit
Downlink (DL) operating bandBS transmit /UE receive
Duplex Mode
FUL_low – FUL_high FDL_low – FDL_high
1 1920 MHz – 1980 MHz 2110 MHz – 2170 MHz FDD
2 1850 MHz – 1910 MHz 1930 MHz – 1990 MHz FDD
3 1710 MHz – 1785 MHz 1805 MHz – 1880 MHz FDD
4 1710 MHz – 1755 MHz 2110 MHz – 2155 MHz FDD
5 824 MHz – 849 MHz 869 MHz – 894MHz FDD
6 830 MHz- – 840 MHz- 865 MHz – 875 MHz- FDD
7 2500 MHz – 2570 MHz 2620 MHz – 2690 MHz FDD
8 880 MHz – 915 MHz 925 MHz – 960 MHz FDD
9 1749.9 MHz – 1784.9 MHz 1844.9 MHz – 1879.9 MHz FDD
10 1710 MHz – 1770 MHz 2110 MHz – 2170 MHz FDD
11 1427.9 MHz – 1447.9 MHz 1475.9 MHz – 1495.9 MHz FDD
12 698 MHz – 716 MHz 728 MHz – 746 MHz FDD
13 777 MHz – 787 MHz 746 MHz – 756 MHz FDD
36.912 v9.0.0 Table 11.2.2-1 Operating bans for LTE-Advanced (E-UTRA operating bands)
Possible new bands
(a) 3.4-3.8 GHz band
(b) 3.4-3.6GHz as well as 3.6-4.2GHz
(c) 3.4-3.6 GHz band
(d) 450−470 MHz band,
(e) 698−862 MHz band
(f) 790−862 MHz ban
(g) 2.3−2.4 GHz band
(h) 4.4-4.99 GHz band
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
13 777 MHz – 787 MHz 746 MHz – 756 MHz FDD
14 788 MHz – 798 MHz 758 MHz – 768 MHz FDD
15* 1900 MHz – 1920 MHz 2600 MHz – 2620 MHz FDD
16* 2010 MHz – 2025 MHz 2585 MHz – 2600 MHz FDD
17 704 MHz – 716 MHz 734 MHz – 746 MHz FDD
18 815 MHz – 830 MHz 860 MHz – 875 MHz FDD
19 830 MHz – 845 MHz 875 MHz – 890 MHz FDD
20 832 MHz – 862 MHz 791 MHz – 821 MHz FDD
21 1447.9 MHz – 1462.9 MHz 1495.9 MHz – 1510.9 MHz FDD
22 3410 MHz – 3500 MHz 3510 MHz 3600 MHz FDD
33 1900 MHz – 1920 MHz 1900 MHz – 1920 MHz TDD
34 2010 MHz – 2025 MHz 2010 MHz – 2025 MHz TDD
35 1850 MHz – 1910 MHz 1850 MHz – 1910 MHz TDD
36 1930 MHz – 1990 MHz 1930 MHz – 1990 MHz TDD
37 1910 MHz – 1930 MHz 1910 MHz – 1930 MHz TDD
38 2570 MHz – 2620 MHz 2570 MHz – 2620 MHz TDD
39 1880 MHz – 1920 MHz 1880 MHz – 1920 MHz TDD
40 2300 MHz – 2400 MHz 2300 MHz – 2400 MHz TDD
41 3400 MHz – 3600 MHz 3400 MHz – 3600 MHz TDD* Defined by ETSI for Europe only
Page 29
Baseline LTE FDD single band architecture
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 30
Source: R4-091204 “Study of UE architectures for LTE-A deployment scenarios” Nokia
4G: Tri-band aggregation plus4x20 MHz contiguous operation
The Hedgehog PhoneTM
“An Antenna for every Occasion”
Supports up to:
• 19 frequency bands
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 31
Source: (Excluding the hedgehog)
R4-091204 “Study of UE architectures
for LTE-A deployment scenarios” Nokia
• 19 frequency bands
• 8 simultaneous radio technologies
• 8x8 MIMO
Fan cooled –Blow dry your hair while you chat…
And for the geeks – A growing gap between conformance testing and real world operation
Attribute Conformance testing Real world operation
MIMO Correlation matrixHigh, medium and zero -
not linked to real antenna
Real correlation based on
actual antenna pattern
Fading channel Extended PA, VA, TU Channels with dynamic taps
Adaptive Modulation & coding
Off – UE becomes fading
channel discriminator
On – coding aims for constant
symbol to noise at UE receiver
CQI, PMI, RI Separate open loop tests Included as part of throughput
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 32
CQI, PMI, RI Separate open loop tests Included as part of throughput
Cell-edge Interference signal
Static wideband
Gaussian
Narrowband frequency-
selective based on loading
Scheduling None, Single UE
Multiple UE, real scheduler with
frequency selectivity base on
subband CQI/PMI
Transmission mode FixedVariable based on prevailing
conditions
Over The Air (OTA) antenna testing
Probably open loopClosed loop with real loading /
scheduler / interference
Concern regarding baseline LTE Rel-8 performance
LTE Rel-8 targets were based on 2x to 4x gains over a limited version of Rel-6 HSPA
• Type 1 receiver – 16QAM Single stream with Rx diversity
A fair comparison would be with Rel-8 HSPA
• Type 3i receiver
• Add dual stream DL 2x2 MIMO
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
• Add equalizer
• Add interference cancellation
• Add 64QAM
On paper the differences between Rel-8 HSPA and Rel-8 LTE are minimal –perhaps 20% in favour of LTE
In practise the advantage will be with the more mature HSPA and may stay that way
Page 33
OFDMA – An unproven cellular technology
Many benefits are expected from OFDMA
• Improved spectral efficiency
• Improved cell edge performance
• Better suited to MIMO
To date there are no commercial OFDMA deployments using 1x frequency reuse
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
• Clearwire using 3x for suburban, 6x urban @ 2.6 GHz
• Single channel 10 MHz @ 700 MHz is a very different scenario
OFDMA Narrowband frequency-selective scheduling creates non-Gaussian cell-edge interference
• 3GPP simulations appear to have used the much easier Gaussian interference model which could inflate expectations
CDMA creates Gaussian interference which can be modelled and cancelled
Page 34
MIMO – An unproven cellular technology
Much has been said about MIMO for many years
We are still a long way from proving its effectiveness in typical
cellular environments
In particular the evaluation of MIMO OTA - Over The Air
• This is a radiated measurement that takes into account the all-
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
important real antenna design
• Expect much angst and gnashing of teeth…
Page 35
Real life MIMO performance
Variation due to
instantaneous
correlation
Variation in the
frequency
This is what we
hear about :
2x gains
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Variation due to fading and variable interference
Most macrocell
activity takes
place in this
region
frequency
domain not
shown
Taking LTE MIMO from Standards to Starbucks
Moray Rumney 10th June 2009Page 36
Managing complexity is an exponential problem(and Moore is not the solution)
For n elements there are n2 - n possible interactions.
E.g. for 50 elements we have 2450 interactions…
Its not that systems can’t work it is primarily that as complexity rises there are just so many operational combinations to design and test for
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
If 4 elements in a system are capable of interacting either in a
linear or complex fashion there are six
bi-directional scenarios to design and test for
But for a system with 9 elements, there are 36
bi-directional scenarios to consider
interactions…
Page 37
Conclusion:Interaction must
be minimized since we cannot
design or test quality into
complex systems
Looking ahead to the Cost/benefits of LTE-Advanced
Bandwidth Aggregation
Enhanced Uplink Higher order MIMO CoMP Relaying
Peak data rates
Spectral efficiency
Cell edge performance
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Coverage
UE cost
Network cost
Complexity (UE) (UE) (Network) (Network)
Page 38
The macrocellular dilemma
To deliver true mobile broadband these three attributes are all
required:
1. High data rates with the capacity and density to match
2. Ubiquitous coverage
3. Low or reasonable cost
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
3. Low or reasonable cost
For macrocellular networks, pick any two!
Page 39
Conclusion: High efficiency macrocellular can’t do it alone.
Some form of small cells is essential.
Evidence of growing problems in the delivery of basic services
No time today for details but:
• Performance of MMS and video calls remain erratic
• SMS becoming less reliable
• Multiple receipts common
• Interworking with CDMA2000 still not figured out after more than a decade – multiple issues
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
decade – multiple issues
• Network generated SMS spam
• Welcome to the Netherlands. What? Again!
• Voice connectivity problems between 2G/3G
• Caller ID frequently fails
Page 40
In a mature market, Value > price > cost
Price
Service
Data rate / volume
Price € Cost / MByte
Price / MByte
Relative price
SMS 160 Bytes €0.15 /
message€ X €1000 400,000
Voice 10 kbps €0.05 to €0.5 /
minute€ Y € 0.7 - € 7 300 - 3000
Data service
(capped at 3
3 GBytes €20 / month € Y/5 € 0.007 3
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
(capped at 3
GBytes)
Unicast Mobile
TV (Capped at
50 hrs)
50 Hours
@ 100
kbps
€5 / month € Y/5 € 0.0023 1
Page 41
Cheap capacity generates unsustainable low value traffic
New air interfaces provide a linear solution to an exponential problem
FCC decision on Net Neutrality
“Broadband providers cannot discriminate against
services or applications by slowing them down”
For wireless, how does it look like from the other end?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Stubbed toe of the decade perhaps?
Page 42
Is that the DoD? I’d like dad’s
newspaper delivered by helicopter please!No charge of course.
Key lessons learned from 20 years of cellular
What we learned from GSM (2G)Scale matters -> 4B devices worldwideUbiquitous low-rate services work and are hugely profitable (voice/SMS)
What we learned from UMTS (3G)A fat circuit-switched data pipe doesn’t cut itCoverage matters
What we learned from HSPA (3.5G)
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
What we learned from HSPA (3.5G)Packet-switched data is essential for mobile broadbandWhen the megabits finally start flowing, data density mattersPricing data at 1% of voice is not sustainable
What we learned from the iPhoneUsability and apps are vastly more critical to innovation than air interfacesWi-Fi is an effective way to offload low-grade traffic from cellular
Page 43
What will it take for LTE to displace existing cellular to deliver on the unified vision?
Sufficient clean spectrum in which to gain a foothold (e.g.
European 800 MHz band)
Network optimization to milk opportunities and overcome
challenges with OFDM
Demonstrated performance to drive obsolescence of legacy and
evolving older technologies
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
evolving older technologies
Solution to Voice support caused by the packet-only network
Proof that IMS is a viable solution for mobile systems
Economies of scale to drive down prices to below legacy
systems
Leave high volume / low value data to Wi-Fi and femtocells
Page 44
In pursuit of excellence
Could we improve on these?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 45
Surely!
But why don’t we?
The return is not worth the pain
The future of wireless is bright…but the future will have to be low cost/complexity
Would you like some nybble and bytes with that Sir?
iFi?
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
iFi?
Page 46
Thank you for listening!
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 47
Backup
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009Page 48
Geometry factor distribution in urban cellsC
um
ula
tive
dis
trib
uti
on
100 %
This plot shows the variation in geometry factor across a typical outdoor urban cell
Very high spectral efficiency is only seen when the geometry factor is above 15 dB, which is an environment that 90% of the user population will not
90% of users 10% of users
Most new high data rate/MIMO
performance targets require
geometry factors
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Geometry factor in dB
Cu
mu
lati
ve
dis
trib
uti
on
0 %
-30 30
that 90% of the user population will not experience
In-building penetration loss will degrade performance further
This puts a finite and very low limit on indoor performance when using outdoor transmission systems
0-20 -10 10 20
geometry factors experienced by
<10% of the user population
Page 49
In search of 21 Mbps
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
Source:
Page 50
Example of interference-limited throughput*
HSDPA macrocell, single Rx + equalizer
15 code 64QAM, 20 Mbps peak
34 randomly distributed users
Quiz #2: What is the combined throughput and why?
M
M
MM
M
MM
M
M M
MM
M
M
MM
M
MM
M
MM
MM
MM
M
M
M
M
M
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
20 Mbps
680 Mbps
13 Mbps
1.3 Mbps
M
MM
M M
* Source: 3GPP RAN WG4 R4-081344
Page 51
That is a median throughput of 40 kbps
(0.26 b/s/Hz)
Impact of femtocell deployment on throughput
Using the same macrocell add 96 femtocells
24 users migrate to femtocells
10 users remain on the macrocell
Quiz #3: What is the combined throughput and why?
M
M
MM
M
MM
M
M M
MM
M
M
MM
M
MM
M
MM
MM
MM
M
M
M
M
M
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
27 Mbps
270 Mbps
2.7 Mbps
1.3 Mbps
That is an medianthroughput of 8 MbpsA 200x improvement!
The remaining macrocell users go from 50 kbps to 170 kbps
M
MM
M M
Page 52
CCDF of throughput with and without femtocells
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
CD
F
Co-Channel, Self Calibrated HNB Tx Power
24 HUEs + 10 MUEs/cell, 1 Rx
34 MUEs/cell, No HNBs, 1 Rx
40 kbps @
50 percentile0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
CD
F
Co-Channel, Self Calibrated HNB Tx Power
24 HUEs + 10 MUEs/cell, 1 Rx
34 MUEs/cell, No HNBs, 1 Rx
8 Mbps @
LTE: Long Term Employment or Less Than Expected?Moray Rumney
28th October 2009
0 1 2 3 4 5
x 105
0
0.1
0.2
All UEs Average Throughput (bps)
Detail showing 40 kbps median for macrocell
Projected spectrum and efficiency gains could push the blue trace to the right by 6x, this femtocell study moved it by 200x
0 2 4 6 8 10 12 14 16 18
x 106
0
0.1
0.2
All UEs Average Throughput (bps)
Full CCDF showing 8 Mbps median for
macrocell plus 24 active femtocells
8 Mbps @
50 percentile
Page 53
2 0 0 9 | W e s t e r g a s f a b r i e k | A m s t e r d a m | http://eComm.ec
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