Comtech - Advanced Backhaul Solutions - Anthony Lomas

1. Advanced Backhaul
Solutions:
November 2012
© Copyright 2012 Comtech EF Data Corporation

2. Best Practices Solution Design
• Before you even run your first link budget
– Understanding your data and the tools that can be used with your
type of data
– Why the characteristics of a link are important to understand
• Preparing a proper link budget
– Amplifier size, linearity, and backoff
– Satellite operation, attenuation, IBO vs. OBO
– Inclined orbit ramifications
• Understanding traffic patterns
– Difference between lossless and non-lossless compression
– Understanding the key benefits between Static and Statistical tools
– What are the ramifications of these tools on my infrastructure / IT
• Lessons learned
2

3. Characteristics of the Traffic
• Circuit based services (Synchronous Data)
– T1, E1,T3, E3, STS-1, STM-1 and OC-3
 Consider underlying protocol requirements
 Typically symmetrical trunking type applications
 Clock and Clock Reference Issues, GPS clocking
 Frame and Superframe bound
 Fixed DR / Fixed Capacity
 Latency and Jitter Issues
• Packet based links
– 100/1000 Ethernet Links, Frame based
 Many types of Ethernet / IP traffic
– Video over IP
– Voice / Pseudowire over IP
– Data
– Mix
3

4. Voice Traffic
• Latency and Jitter considerations
– Quality impacted by high latency and jitter
– Latency impacted by sizing of Jitter queues
• Typically small transport packets cause high
overhead
• Traffic dimensioned using Erlang models, statistical
estimates of Busy Hour traffic
• No retransmission of lost transport packets
• No queuing if congestion occurs, needs congestion
managements techniques
4

5. Bandwidth on Demand for GSM and
Erlang
• Customer with 48 sites deployed across 3 highway spans
provided detailed Erlang information per site.
• Memotec analysis showed that network design based on pt-to-
mpt topology was optimal (forward 2.8Mbps, returns 6.8Mbps).
5
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Note: despite TDMA vendor claims, all
sites reach peak at same time
defeating argument of bandwidth
sharing across IP/TDMA VSAT
networks. Only SCPCs can offer low
latency and jitter while providing
optimal modulation and coding (lowest
cost bit/hz).
Note: Peak utilization for
16hrs per day
Comtech EF Data Confidential

6. Characteristics of Link
• Is there existing infrastructure
– Limitations on Satellite Dish size / location
– Limitations on existing Amplification Systems
• Is the link Symmetric or Asymmetric
– In terms of user traffic
– In terms of ground resources
• What kind of satellite is being considered
– Cross Strapped vs. bent pipe
– Frequency Band
– Beam (Global, Hemi, Spot)
– Inclined Orbit
– Fixed Services Satellite (FSS), High speed Trunking Satellite (HTS)
6

7. Tools to reduce BW usage
• Difference between Static and Statistical savings
– Static advantage is a calculable and definitive advantage for
the life of the circuit
 Improvements in FEC
 Carrier in Carrier Technology
– Statistical advantages rely on probability, advantage is
averaged over time but is rarely exact at any instant
 AUPC and CnC-APC
 Compression and Optimization
 Adaptive Coding and Modulation (ACM)
7

8. Static Advantages
FEC and Coding Gain, Carrier in Carrier Technology
8

9. FEC and Coding Gain
Design Considerations
9

10. Improvements In FEC
(Forward Error Correction)
• Shannon-Hartley Bound: There is a maximum bound
on the amount of error free data that can be
transmitted though a noisy transmission medium
10
Coding Type Vs. Shannon Bound
Sequential or Viterbi + 4-8 dB
Turbo Product Codes + 2-3 dB
Versa FEC + 1-2 dB
DVB-S2 LDPC+BCH + 0.7 – 1.5 dB

11. Advances in Coding Gain on:
Fixed BW Maximize Throughput
11
Viterbi + RS TPC Coding Versa FEC DVB-S2
Fixed C/N 6.0 dB 6.0 dB 6.0 dB 6.0 dB
Best Modulation /
Coding for Es/No
QPSK ½ QPSK ¾ QPSK .803 QPSK 5/6
(.827)
Spectral Efficiency 0.92 bits / Hz 1.5 bits / Hz 1.61 bits / Hz 1.65 bits / Hz
BW = SR 5.0 MHz 5.0 MHz 5.0 MHz 5.0 MHz
User Data Rate 4.6 Mbps 7.5 Mbps 8.1 Mbps 8.3 Mbps

12. Carrier in Carrier
Design Considerations
12

13. DoubleTalk® Carrier-in-Carrier®
• Based on patented “Adaptive Cancellation”, Carrier-
in-Carrier (CnC) allows carriers in a Duplex satellite
link to occupy the same transponder space
13
Without DoubleTalk Carrier-in-Carrier With DoubleTalk Carrier-in-Carrier
Carrier-in-Carrier is a Registered Trademark of Comtech EF Data
DoubleTalk is a Registered Trademark of Applied Signal Technology, Inc.

14. Multi Dimensional Optimization
• Combined with proper Modulation and FEC, Carrier-in-
Carrier allows for multi dimensional optimization
– Reducing OPEX
 Occupied Bandwidth & Transponder Power
– Reducing CAPEX
 BUC/HPA Size and/or Antenna Size
– Increasing throughput
– Increasing link availability
– Or a combination to meet different objectives
14

15. Extreme Spectral Efficiency
• Carrier-in-Carrier can be used to achieve
extreme spectral utilization that would not
otherwise be possible
• Best DVB-S2 Spec Efficiency = 4.45 b/Hz
– Asia: 16APSK ¾ FEC --- 90Mbps DPLX in 15.5MHz
 Spectral Eff = 5.78 b/Hz = 64QAM
– US: 32APSK ¾ FEC --- 217Mbps DPLX in 30MHz
 Spectral Eff = 7.24 b/Hz = 256QAM
– THESE ARE CABLE MODEM FIGURES
15

16. Statistical Advantages
AUPC, Compression, Optimization, ACM

17. AUPC and CnC-APC
Design Considerations
17

18. AUPC vs CnC-APC
• AUPC (Automatic Uplink Power Control)
– Modem technology
 Historically simplistic method
 Change in uplink power due to Es/No fade at demod
 Does not differentiate between uplink or downlink fade
• CnC-APC
– Modem and CnC combined technology
 Non simplistic method
 Can discern between uplink and downlink fade
 Improves effective link margin
 Improves availability in CnC links
18

19. AUPC
• Compensates for ANY fade condition by increasing
TX power
19

20. CnC-APC
• Modems on a CnC link to automatically compensate
for rain loss while maintaining a fixed PEB
• CnC modems share link margin between each other
20

21. Compression and
Optimization
Design Considerations
21

22. Compression and Optimization
Advantages
Technology Business Benefits Quantifiable Benefits
RAN Optimization/Multiplexing • Relieves congestion
• Makes room for 3G
• 50% (average) backhaul bandwidth reduction
IP Optimization &
Acceleration/Caching
• Enhances user experience • 50% (average) bandwidth, and Latency
mitigation
IP Header & Payload Compression • Reduces OPEX • 30% (average) payload , 60% (average)
header bandwidth reduction
Ultra-Low Overhead Protocols • Reduces OPEX • 60% (average) overhead reduction
Superior Modulation, ACM • Increases service availability
• Enhances user experience
• Reduces CAPEX
• 50% (average) throughput gain of
• Use of a smaller BUC/HPA and/or antenna
Advanced Forward Error Correction
and Protocols
• Increases service availability
• Enhances user experience
• Reduces CAPEX
• 30% (average) more throughput for same
transponder
• Use of a smaller BUC/HPA and/or antenna
Reduce Costs, Enhance User Experience
22

23. Compression
• Can my data be compressed?
– Synchronous Data
– Packet Based Data
• Does my transport interface allow for compression
• Lossy Compression vs. Lossless Compression
– Lossy compression can be used on voice, video and
multimedia
– Lossless compression is the only compression suggested for
data
• How much can I expect my traffic to compress?
– Good Question
23

24. Lossy Compression
24
Uncompressed Lossy Compression

25. Lossless Compression (Data)
25
• Pattern recognition: 20 bytes of data is represented by 12 bytes
40% Savings

26. Adaptive Coding and
Modulation
Design Considerations

27. Adaptive Coding & Modulation (ACM)
• Adaptive Coding & Modulation (ACM)
converts the link margin into increased
capacity – average throughput gain of
100% (or more) is possible, compared
to traditional CCM
– Most of the year, the link operates at
significantly increased throughput
– For the worst few hours of the year, the link
may be available with lower throughput
27

28. ACM Concept is Simple
• (ACM) allows for automatic change in Modulation and
Coding in response to current link conditions
• Symbol Rate and Transmit Power are fixed and the
data rate changes as the modulation and code rate are
changed
– ACM carriers use fixed bandwidth and power on the
transponder
– The receiving modem in a link, provides signal quality updates
to the transmit modem
– The transmit modem changes the Modulation and/or Code
Rate to the most spectrally efficient Mod/Cod for the current
conditions
28

29. Adaptive Coding and Modulation
(ACM)
• What type of advantage is ACM?
– ACM is a Statistical, non-static throughput advantage
– The advantage due to ACM will dynamically change
– Throughput can not be guaranteed but is predictable
– Will work on cross-strapped transponders
– All margin (antenna pointing, incl orbit, rain fade, link budget
margin, etc.) can be turned into higher capacity throughput
• What are the restrictions?
– Must be a closed loop system (feedback to uplink modulator)
– Must have sufficient system link margin to be of value
– Must be a packet based or scaleable link (not synchronous)

30. Overall Link Margin
• ACM’s value is in the conversion of Link Margin
• Greater the Link Margin the greater the value of ACM
• Most Link Margin boils down to two main factors:
– Link availability (99.8% vs. 99.6%)
– Effects of Rain Fade (Ku-Band vs. C-Band)
30

31. Ku-Band Link Margin
(Germany – Nigeria)
0
5
10
15
20
25
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9999,199,299,399,499,599,699,799,899,9100
Margin(dB)
Annual Availibility
Figure 1: Ku-Band Link Margin (dB)
Margin (dB)
2.5 dB Margin
equates to
+/- 0.2%
Availability
31

32. C-Band Link Margin
(Italy – China)
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9999,199,299,399,499,599,699,799,899,9100
Margin(dB)
Annual Availibility
Figure 2: C-Band Link Margin (dB)
Margin (dB)
0.35 dB Margin
equates to
+/- 0.2%
Availability
32

33. Overall Link Margin
33

34. How Does C/N Convert to User DR
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SpectralEfficiency
Es/No (Ideal)
DVB-S2 Es/No Performance at Quasi Error Free
PER=10-7 64K Blocks w/ Pilots
S2-QPSK
S2-8PSK
S2-16APSK
S2-32APSK
34
5.5 dB
Margin
1 dB of converted margin = 10-15% DR Increase
5.5dB of converted margin = 55% -> 83% DR Increase

35. ACM in Operation
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Mbps
ACM Operation and User Throughput
User DR
Avail DR
Rain fade: 2.2 dB
16-APSK 5/6 @ 64 Mbps
To
16-APSK 2/3 @ 51 Mbps
Deep Rain fade: 6.9 dB
16-APSK 5/6 @ 64 Mbps
To
QPSK 4/5 @ 31 Mbps

36. Inclined Orbit Issues
• Inclined Orbit satellites create unwanted effects on
the ground. Creates downlink beam movement that
appears to the ground station as a sinusoidal EIRP
change that will grow as the inclination grows.
36

37. Inclined Orbit Effect on Es/No
• EIRP at Beam Contours will Fluxuate
• This creates Es/No changes as seen by ground
• How to compensate for Es/No changes
– Design system for worst case Es/No
– Use tools such as ACM to adjust data throughput
37

38. Proper Pt-Pt ACM Implementation
38
Monitor
WAN
Capacity
Ingest
Data
WAN OP
Prioritize
Data
based on
filter
rules
Drain
Data
Based on
drain
rules

39. Monitor WAN Capacity
39
FX QOS/PEP CDM-750
Feedback
TX Capacity
• Constant monitor of the CDM-750 TX WAN capacity
ensures QOS / WAN OP are enforced and maximize
throughput

40. Voice
Voice
40
Proper Pt-Pt ACM Implementation
Ingest Data
FX QOS/PEP
Signalling
Voice
Video
HTML Signalling
Voice
Video
HTML
• Data Ingest of all traffic destined for the WAN
All Traffic Ingested

41. Proper Pt-Pt ACM Implementation
Prioritize Data
• Various rules and filters can be used
• All traffic is associated with a priority classification
41
Voice Voice
FX QOS/PEP
Signalling
Video
HTML
Signalling
Voice
Video
HTML
Rules / Filters
Protocol
IP Subnet
VLAN ID
DiffServ
Destination Port
Priority Classification
1
2
3
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42. Proper Pt-Pt ACM Implementation
Data Drain
• Drain rules are applied to minimize latency and
ensure high priority traffic maintains CIR
42
Voice Voice
Signalling
Video
HTML
Signalling
Voice
Video
HTML
Priority Classification
1
2
3
4
Drain Options
Strict Priority
Fair Weighted
Min / Max
Signalling
Signalling
Voice
Voice
Video
Drain Algorithm

43. Carrier ID
Reduction in Satellite Carrier Interference

44. Carrier ID to Reduce Interference
• By 2009, Satellite operators and service providers
recognized that the time they were spending on
interference mitigation was increasing
• The SUIRG had been created a few years earlier,
and had proposed the use of the Network Information
Table (NIT in the MPEG-2 profile) as the location for
Carrier ID
• The SUIRG started searching for techniques to
address installed legacy equipment for VSAT and
Data modems
• They created requirements for this Carrier ID;
44Comtech EF Data Proprietary

45. The SUIRG Carrier ID Requirement
• The Carrier ID must be read in the clear, by a
properly configured Carrier ID receiver, even if the
referenced carrier is encrypted.
• The Carrier ID must be transmitted in an industry
accepted format, so that the number and type of
Carrier ID receivers are kept to a minimum.
• The Carrier ID insertion must have a minimal effect
on the data carrier overhead, efficiency, Es/No,
phase noise and other carrier quality measurements.
45Comtech EF Data Proprietary

46. Comtech EF Data Created the
MetaCarrier™ for Carrier ID
• MetaCarrier means that we have a separate spread spectrum
carrier that contains information that is used to describe another
single carrier
• The MetaCarrier is embedded within the carrier, without adding
appreciable noise to the carrier, and is completely waveform
agnostic
• This version works for static carriers, video and SCPC
• During 2010 this had been demonstrated to Intelsat, SES,
Turner, and CBS with a month long national feed demo
• The WBU-ISOG, sIRG, RFI-EUI and GVF started supporting
and promoting it

47. Carrier ID Awareness

48. • During the 2011 IBC the sIRG held a meeting with modulator manufacturers with
the intention of submitting it to the DVB for standardization
• In December 2011 the first DVB Commercial Module meeting for Carrier ID took
place with the DVB and DVB members
• The commercial requirements were adapted by the DVB Commercial Module on
Feb 15 2012
• The standard is based on our original design along with complimentary input
from others (noteably Newtec)
• Technical details you may not care about such as scrambler method, power
levels, transmission sequencing etc. have slightly changed since our original
design
• The Technical Module is underway and will submit it’s draft for comment at the
next general TM meeting in January 2013
Carrier ID Progress within the DVB

49. Carrier ID Progress Outside of the
DVB
• Longer term operation underway during and after this past
Summer Olympics
– MetaCarrier Carrier ID embedders installed on Intelsat North
America, SES Europe and Eutelsat Carrier ID test carriers
• Detectors for the MetaCarrier Carrier IDs are installed at Carrier
Monitoring System manufacturers for the development of their
specific monitor and control interfaces
– Crystal Solutions
– Sat Corp (Monics)
– Siemens AG
• The FCC has issued a notice of proposed rulemaking for part 25
(satellite operation) that recommends adaptation of either the
NIT or a spread spectrum technique; comments from industry
are due by December 24th

50. Carrier ID Implementation
Requirements
• For implementation in a modulator
– The modulator must have enough FPGA resource to support
this additional feature
– This may require a trade-off by the manufacturer to drop
legacy features that the market no longer requests
– Comtech modulators will support the DVB Carrier ID starting
three months after the DVB standard is issued
Comtech EF Data Proprietary & 50

51. African Design Success
GSM over Satellite

52. Success Story
• Africa
– Providing service across 14 African countries including
Chad, Ghana, Niger, Burkina Faso, Sierra Leone, Nigeria,
DRC, Congo Brazzaville, Zambia, Madagascar, and
Tanzania
– Bundle CDM625 CnC + CXU Abis Optimizer solution
 CDM625 with CnC and VersaFEC for satellite efficiency
 CXU for GSM 2G Abis layer efficiency
– Deployed as point-to-point Abis links (BTS) backhaul
– Standardized solution with eye toward OPEX savings.
DS0 Aggregation -D&I-
and 2:1 optimization
SAT modemSAT modem
GSM BSC GSM

53. Success Story
• Amongst fierce competitive and price pressures
where every tactic is important, the measurable
impacts are therefore in the following areas:
– OPEX decrease in satellite transponder lease
– Minimum US$600K OPEX savings per year just on
upgrading the existing links (new deployments accounted
separately)
– Increase in number of customers in rural areas due to
extended coverage, high quality of service, affordable
services
– Decrease in end user pricing
53

54. Success Story
• Airtel added 8.9 million customers during the year
(March 2012 estimates). The growth of 20% in the
customer base has translated into higher
consumption of minutes on the network, thereby
driving robust revenue growth. And, the satellite
backhaul strategy has been a key element in
supporting the growth.
54

55. Award Winning Solution
55

56. Comtech EF Data
2114 West 7th Street
Tempe, AZ 85281
USA
Tel +1.480.333.2200
FAX +1.480.333.2540
sales@comtechefdata.com
www.comtechefdata.com