WHAT DO HIGHER DATA RATES MEAN
TO CELLULAR AND CONNECTIVITY
TESTING?
WIRELESS INDUSTRY TRENDS
Key market drivers for the wireless industry:

Smartphone & Tablet Continuing to Grow Worldwide
–
–
–
Units increasing by 340M units to 2.45B annually by 2018
Handset ASP shrinking by >5% YoY
Companies releasing 2x - 3x more new designs annually
to meet both premium & basic smart phone demands

Shrinking Device Size While Increasing Complexity
–
–
–

Mobile IC’s moving away from conventional package to wafer-level
package technologies (Flip-chip, WLCSP, FOWLP)
Wafer Scale Package technologies provide 50% smaller device
footprint
Shrinking geometries (65nm  45nm  28nm) enabling 2x – 3x
content increases on smaller die sizes
Increase Demand for Higher Data Rate & Connectivity
–
–
–
Overall mobile data traffic is expected to grow at a 61%
CAGR to 15.9 Exabytes per month by 2018
MIMO & Carrier Aggregation requiring 2x-3x more active RX
& TX device ports
Internet-of-things driving rapid growth of MCU + RF segment
METHODS OF INCREASING DATA RATE
Very High Throughput requirements are met three ways:
1) Increasing BW.
•Wider Bandwidths / Aggregation
2) Increasing the number of bits/symbol.
• Constellation Density
• Link Adaptation & Fast Scheduling
• UL / DL ratio
• Forward Error Correction
•Cyclic Prefix reduction
3) Increasing the number of Spatial Streams.
•Diversity
•Beam forming
•MIMO
•MU-MIMO
64 QAM
Spatial
Multiplexing
Multi-User
MIMO
3
256 QAM
TWO STANDARDS – W-CDMA AND OFDM
• Early Communications
-1000G – Coded Message
-500G – First Cell
(-2000G - BPSK)
4
TWO STANDARDS – W-CDMA AND OFDM
• Problems with using Smoke to send messages - WIND
-500G
-400G
3G
W-CDMA
Raised Root Cosine
Filter w/ Alpha = 0.22
(HSPA+)
WCDMA – Has similar traits to smoke, in that its noisy and is
required to be filtered to stay with in its allocated frequency. This
hinders WCDMA from making the best use of its bandwidth.
5
TWO STANDARDS – W-CDMA AND OFDM
• Early Communications
-2200G
-240G – Coded Message
Spatial Separation
Would have helped
-150G – Coded Message
Frequency and Spatial
Separation combined
3G
OFDM
(802.11a,g,n,ac & LTE)
OFDM used for LTE and WLAN – Has similar traits to light, in that if the
frequencies have a minimal separation – they tend not to interfere with
each other. This allows OFDM to make good use of its spectrum.
6
METHODS OF INCREASING DATA RATE
Very High Throughput requirements are met three ways:
1) Increasing BW. (LTE 100M Aggregation, 802.11ac 160M)
•Wider Bandwidths / Aggregation
2) Increasing the number of bits/symbol. . (LTE 64 QAM , 802.11ac 256 QAM)
• Constellation Density
• Link Adaptation & Fast Scheduling
• UL / DL ratio
• Forward Error Correction
•Cyclic Prefix reduction
3) Increasing the number of Spatial Streams. (802.11ac supports up to 8x8 MIMO)
•MIMO
7
CELLULAR EVOLUTION
802.11a/b
802.11g
802.11n
802.11ac
802.11ad
WIDER BANDWIDTH & AGGREGATION – HIGHER DATA
RATES
• LTE Supports many different
types of bandwidth
configurations. 1.4,3,5,10,20M
and any combo up to 100M
• TEST – support required
bandwidth
20
MH
z
LTE-Advanced
Maximum Bandwidth
5 x 20MHz
20
20
20
MH
z
MH
z
MH
z
20
MH
z
10
WIDER BANDWIDTH & AGGREGATION – HIGHER DATA
RATES
• 802.11ac
Supports many
different types of
bandwidth
configurations.
20,40,80,160M
• Note that there is also
an aggregation mode
for 802.11ac – that’s
called 80+80.
11
WIDER BANDWIDTH & AGGREGATION – TEST
• High frequency modulation signal
• Sourcing a wider bandwidth signal requires much better baseband
instruments than narrow band signals. Skew is one of the biggest concerns.
The UltraWave 12G, UltraWave 24, and the UltraPAC80 have skew accuracy
and repeatability performance to test wide bandwidth waveforms.
I and Q Timing Skew effects on EVM
7
6
802.11ac 160M 256QAM
LTE-Adv 100M 64 QAM
802.11ac 160M
EVM Limit = 2.51%
4
802.11ac 80M 256QAM
802.11ac 80M QPSK
3
802.11ac 40M 256QAM
LTE 20M 64QAM
2
1
500
475
450
425
400
375
350
325
300
275
250
225
200
175
150
125
75
100
50
25
0
0
% EVM
5
12
METHODS OF INCREASING DATA RATE
Very High Throughput requirements are met three ways:
1) Increasing BW. (LTE 100M Aggregation, 802.11ac 160M)
•Wider Bandwidths / Aggregation
2) Increasing the number of bits/symbol. . (LTE 64 QAM , 802.11ac 256
QAM)
• Constellation Density
• Link Adaptation & Fast Scheduling
• UL / DL ratio
• Forward Error Correction
•Cyclic Prefix reduction
3) Increasing the number of Spatial Streams. (802.11ac supports up to 8x8
MIMO)
•MIMO
13
CONSTELLATION DENSITY – HIGHER DATA RATE
Measured Signal
• 16 QAM = 4 Bits per symbol
• 64 QAM = 6 Bits per symbol
• 256 QAM = 8 Bits per symbol
Test Limit
Ideal Signal
• Constellation Density is determined by quality of the signal at the RX.
If poor signal / bits dropped – Then the TX reduces the density.
LTE Base Station = 13.5%
LTE User Equip 12.5%
802.11ac = 11.22%
16-QAM
802.11a/g, LTE
LTE Base Station = 9.0%
802.11ac = 3.98%
64-QAM
802.11a/g/n; LTE-A
802.11ac = 2.51%
256-QAM
802.11 14
ac
- Device Spec Limit
WHAT IS KNOWN ABOUT THE CHANNEL?
• In order to achieve higher data rates – some methods
require an understanding of the channel.
• This channel information is communicated to the base
station (BS) by the user equipment (UE) or its signal.
– FDD vs. TDD - TDD can be have more up to date information,
because UL shares the same channel as DL
UL
?
DL
15
LINK ADAPTATION & FAST SCHEDULING
• Link Adaptation - Data Rates are varied based of information about the
channel at a given time. TDD is often more up to date.
– Used with - 802.11ac & HSPA + & LTE
• Fast Scheduling – When users data is sent the data rate can vary to take
advantage of better channel conditions – Resulting in higher data rate =
less on time = better battery life.
– Used with - HSPA+ & LTE
• TEST
– Data Rate normally does not change during test
– However VSA can handle it.
LTE Example - Resource Blocks Data Rate vs Channel
16
UL / DL RATIO – HIGHER DATA RATE
• In order to be flexible with users needs for more UL or
more DL a scheduling plan was created. Below is an
example for LTE TDD
– HSPA+
• HSDPA was designed to favor DL and HSUPA for UL. HSPA+ was
designed to be more flexible with DL and UL scheduling.
• TEST – Normally this does not change during test
LTE - TDD
17
OTHERS
• Forward Error correction (FEC)
802.11a/g
Data Rate
(Mbps)
Modulation
Type
(OFDM)
Punctured
Coding
48
64-QAM
2/3
54
64-QAM
3/4
•Cyclic Prefix reduction – Higher Data rate
FFT Window
18
METHODS OF INCREASING DATA RATE
Very High Throughput requirements are met three ways:
1) Increasing BW. (LTE 100M Aggregation, 802.11ac 160M)
•Wider Bandwidths / Aggregation
2) Increasing the number of bits/symbol. . (LTE 64 QAM , 802.11ac 256
QAM)
• Constellation Density
• Link Adaptation & Fast Scheduling
• UL / DL ratio
• Forward Error Correction
•Cyclic Prefix reduction
3) Increasing the number of Spatial Streams. (802.11ac supports up to 8x8
MIMO)
•MIMO
19
MIMO – HIGHER DATA RATES
• MIMO - Multiple Input into the channel and Multiple Outputs from the channel.
• MIMO utilizes the multi-path environment so that signals are different.
• MIMO uses two or more antennas to transmits different information on each
antenna. For each antenna added the data rate is increased by the multiple
of the number of antennas over the SISO rate.
• Each MIMO stream contains not only the data, but information that will assist
the receiver in demodulating the signal. This advancement in MIMO
technology is primary due to higher end processor that are able to do the
math to pull the data apart.
• TEST
• Each path should be active and can be tested as MIMO or Signal Channel.
• Cross talk between streams can be tested with ESA – however seldom is
20
TESTING CHALLENGES
1. Provide full test coverage to
guarantee device quality
• RF Source Accuracy
• EVM test capability
• ACLR performance for out of band
service providers compliance
Source: www.qualcomm.com
LTE Commercial Release Timeline
2. Provide economical solution for high volume production
LTE-Advanced requires up to 5x modulated data compared to 3G.
ULTRAFLEX RF:
#1 PRODUCTION SOLUTION FOR WIRELESS
Teradyne: #1 ranked RF ATE company since 2008
(source: Gartner, April 2014)
UltraFLEX RF Specifiers:
Based on 2013 Reported Revenue (Gartner, April 2014)
UltraFLEX RF Test Partners:
>515 UltraFLEX RF systems
installed since 4Q-2007
 Lowest cost of test
 Fastest time to market
 Highest performance instruments
 Easiest to use software
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