ADVANCED COMMUNICATION SOLUTIONS CDM-Qx/QxL Satellite Modem with DoubleTalk TM Carrier-in-Carrier ®...

ADVANCED COMMUNICATION SOLUTIONS

CDM-Qx/QxL Satellite Modem withDoubleTalkTM Carrier-in-Carrier®

The Most Bandwidth Efficient Modem Ever !

March 2007

2

Agenda

• DoubleTalk Carrier-in-Carrier Overview

• Business Case - Why use CDM-Qx/QxL with DoubleTalk Carrier-in-Carrier ?

• CDM-Qx/QxL Overview– Architecture– Features– Configuration

DoubleTalk is a Trademark of Applied Signal TechnologyCarrier-in-Carrier is a Registered Trademark of Comtech EF Data

All specifications are subject to change without notice.

3

SATCOM Optimization

• Satellite Communication (SATCOM) users have always been confronted with power and bandwidth tradeoffs to achieve maximum efficiency

• Now Comtech EF Data introduces a new product and a new technology that adds a new dimension to SATCOM optimization– CDM-Qx with DoubleTalk Carrier-in-Carrier is the

most bandwidth and power efficient satellite modem available commercially

4

Optimize SATCOM

• CDM-Qx/QxL with DoubleTalk Carrier-in-Carrier makes it possible to optimize satellite communications in multiple ways– Reduce OPEX– Reduce CAPEX– Increase throughput– Increase link availability– Reduce rack space

5

DoubleTalk Carrier-in-Carrier

• Based on Applied Signal Technology’s (APSG) DoubleTalk™ bandwidth compression system – Uses patented “Adaptive Cancellation” – Allows full duplex satellite links to

transmit concurrently in the same segment of transponder bandwidth

• Comtech EF Data licensed the technology from APSG, and after integrating it with CDM-Qx, is offering it as DoubleTalk Carrier-in-Carrier– Delivers unprecedented operating

expense savings when combined with Comtech EF Data’s advanced Forward Error Correction and Modulation techniques

Without DoubleTalk Carrier-in-Carrier

With DoubleTalk Carrier-in-Carrier

6

DoubleTalk Carrier-in-Carrier Theory of Operation

Mod_1 Demod_1 Demod_2 Mod_2

S1 S2

S1*'+ S2

*'

S1* S2

*S1 S2

S2 S1

S1*'+ S2

*'

7

Theory of Operation (cont’d)

• At start-up, the exact round-trip delay is calculated

• The modulator provides a copy of the time delayed transmitted signal to the demodulator

• The demodulator “cancels” the time delayed transmitted signal from the composite received signal– Nominal cancellation is 25 dB to 30 dB– The residual interfering signal appears as noise

i.e. the Noise Floor is raised, slightly degrading the Eb/No

8

Eb/No Degradation - QPSK

• Very low degradation when using QPSKEb/No Degradation vs Carrier Power Ratio (QPSK)

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

-10 -5 0 5 10

Interferer - Desired Carrier Power (dB)

Eb

/No

Deg

rad

atio

n (

dB

)

QPSK, TPC 17/18

QPSK, TPC 3/4

QPSK, TPC 21/44

QPSK, TPC 7/8

9

Eb/No Degradation – 8-PSK

• Low degradation except for TPC, Rate 17/18

Eb/No Degradation vs Carrier Power Ratio (8-PSK)

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

-10 -5 0 5 10


Eb

/No

Deg

rad

atio

n (

dB

)

8-PSK, TCM 2/3

8-PSK, TPC 7/8

8-PSK, TPC 3/4

8-PSK, TPC 17/18

10

Eb/No Degradation – 16-QAM

• Low degradation for TPC, Rate 3/4Eb/No Degradation vs Carrier Power Ratio (16-QAM)

-2.0

-1.8

-1.6

-1.4

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

-10 -5 0 5 10


Eb

/No

Deg

rad

atio

n (

dB

)

16-QAM, TPC 3/4

16-QAM, TPC 7/8

11

DoubleTalk Carrier-in-Carrier Operational Rules

• Full-duplex links only– CDM-Qx must be configured as a “Modem”

• “Loop-back” satellite (i.e. the transmitting station must be able to receive itself)

• “Non-processing” satellite (i.e. does not demodulate/ remodulate the signal)

• Symbol rate asymmetry of the 2 carriers should be within 3:1 for optimal performance

• (Interfering carrier power – desired carrier power), in dB, < 10 dB (except for 16QAM, R=7/8)

• Carrier offset within ±32 kHz– i.e., Center frequencies of the desired and the interfering carriers

are within ±32 kHz

12

Bandwidth Limited vs. Power Limited Links

• DoubleTalk Carrier-in-Carrier provides a mechanism to trade bandwidth and power

• Contrary to intuition, DoubleTalk Carrier-in-Carrier can be used to achieve bandwidth and power savings in Bandwidth Limited as well as Power Limited scenarios– Recover power by using a lower order modulation

& FEC– This increases the occupied bandwidth– Use DoubleTalk Carrier-in-Carrier to reduce

occupied bandwidth

13

How To Use DoubleTalk Carrier-in-Carrier

8PSK A => B B => ATypical 8PSK Link

QPSK

8PSK QPSK (Spreading)Bandwidth increases,

Power decreasesA => B A => B

Original Link shownfor Reference

QPSK - WithDoubleTalk

Carrier-in-Carrier

Apply DoubleTalk Carrier-in-Carrier -Composite Carrier uses Less Bandwidth

& Less Power Compared to Original

Composite Link

14

CAPEX Reduction

• Carrier spreading combined with DoubleTalk Carrier-in-Carrier allows CDM-Qx to achieve equivalent spectral efficiency (i.e. bps/Hz) using a lower order Modulation and/or FEC Code compared to any other modem

• This translates into– Smaller BUC/HPA size– Smaller antenna size

• This is in addition to monthly leased bandwidth savings

15

Customer Example 1

• C-band• 13 m to 9.15 m• Original Link is Bandwidth Limited

A to B B to A Total

Data Rate 1544 kbps 1544 kbps

Modulation 16QAM 16QAM

FEC TPC, R=3/4 TPC, R=3/4

% BW 1.94% 1.94% 3.88%

% Power 0.53% 0.44% 0.97%

Leased BW 3.88%Tx Power @ Flange

0.07 W 0.26 W

16

Customer Example 1 (cont’d)

• With DoubleTalk Carrier-in-Carrier– Still Bandwidth Limited

A to B B to A Total Comments

Data Rate 1544 kbps 1544 kbps

Modulation 16QAM 16QAM


% BW 1.94% 1.94% 1.94%

% Power 0.82% 0.70% 1.52%

Leased BW 1.94% 50% SavingTx Power @ Flange

0.11 W 0.41 W

17

Customer Example 2

• Ku-band• 5.6 m to 2.4 m • Original Link is Power Limited

A to B B to A Total

Data Rate 1698.4 kbps 1698.4 kbps

Modulation 8-PSK 8-PSK


% BW 3.06% 3.06% 6.12%

% Power 3.61% 3.61% 7.22%


14.95 W 1.69 W

18


• Lets add DoubleTalk Carrier-in-Carrier without making any other change

Leased Bandwidth increases to 8.48% from 7.22%Transmit Power @ Flange also increases

This DID NOT HELP

A to B B to A Total


Modulation 8-PSK 8-PSK


% BW 3.06% 3.06% 3.06%

% Power 4.27% 4.21% 8.48%


17.68 W 1.97 W

19


• Now use spreading along with DoubleTalk Carrier-in-Carrier

A to B B to A Total Comments


Modulation QPSK QPSK


% BW 3.89% 3.89% 3.89%

% Power 2.09% 2.20% 4.29%

Leased BW 4.29% 41% Saving

Tx Power @ Flange

8.65 W 0.82 W42% & 51%

Savings Respectively

20

Customer Example 3 – Cellular Backhaul

• Network– 26 x E1 full duplex links

99.95% availability

– Hub 7.2 m antenna

– 26 Remote sites 3.7 m antenna

• C-Band Satellite– EIRP: 37.5 dBW– SFD: -84 dBW/m2

– G/T: -4 dB/K– $3,000 / MHz / month

• Conventional Link– Hub to Remote

QPSK, TPC R=7/8

– Remote to Hub 8PSK, TPC R=7/8

• DoubleTalk Carrier-in-Carrier Links– Mix of QPSK, TPC R=3/4 &

QPSK, TPC R=7/8

21

Customer Example 3 – Cellular Backhaul (cont’d)

• Leased bandwidth (OPEX)– Conventional Link

66 MHz $198K per month

– CDM-Qx with DoubleTalk Carrier-in-Carrier

44 MHz $132K per month

– Monthly savings ~ $66K

• CAPEX– Modem price

~ $4.5K additional per CDM-Qx ~ $234K total additional CAPEX

– Remote BUC ~ $6K saving per remote site

when using CDM-Qx ~ $156K total saving

– Hub SSPA 1000W HPA at Hub in both cases

– Total CAPEX difference ~ $78K additional CAPEX in a 27

node network with total CAPEX of over $1 million

Payback ~ 1.2 monthOver $790K Annual Savings Thereafter

22

Customer Example 4 – Cellular Backhaul

• Hub-Spoke network with E1 links– 7.2 m Antenna at Hub– 3.7 m Antenna at Remote– C-Band satellite

EIRP: 36 dBW SFD: -85 dBW/m2

G/T: -2 dB/K

– BER: 1.0E-07

23


• Conventional Link– Hub to Remote: QPSK, TPC R=7/8

Allocated BW – 1521 kHz Power Equivalent Bandwidth (PEB)

– 900 kHz Transmit Power @ Flange – 2 W

– Remote to Hub: 16QAM, TPC R=7/8 Allocated BW – 761 kHz Power Equivalent Bandwidth – 1396

kHz Transmit Power @ Flange – 12 W

– Requires 40W HPA/BUC

– Total Allocated BW – 2282 kHz Power Equivalent BW – 2296 kHz Leased Bandwidth – 2296 kHz

– Link is Power Limited

• With DoubleTalk Carrier-in-Carrier– Hub to Remote: QPSK, TPC R=7/8

Allocated BW – 1521 kHz Power Equivalent Bandwidth

(PEB) – 1027 kHz Transmit Power @ Flange – 2.3 W

– Remote to Hub: QPSK, TPC R=7/8 Allocated BW – 1521 kHz Power Equivalent Bandwidth – 325

kHz Transmit Power @ Flange – 2.7 W

– Requires Only 5W HPA/BUC

– Total Allocated BW – 1521 kHz Power Equivalent BW – 1352 kHz Leased Bandwidth – 1521 kHz

– Link is Bandwidth Limited

24


• Conclusions – Leased bandwidth savings of 775 kHz (34%)– The new link being BW limited, has enough

additional transponder power to provide additional link margin of 0.5 dB in each

direction or improve BER from 1.0E-07 to better than 1.0E-09

– Remote HPA/BUC size reduction from 40W to 5W– Insignificant increase in Tx Power@Flange at Hub

25

Is DoubleTalk Carrier-in-Carrier Always The Best Solution ?

• Greenfield installations– Generally with savings from BUC/HPA size reduction, and

possible Antenna Size reduction, CDM-Qx with DoubleTalk Carrier-in-Carrier can pay for itself in as little as 0 – 3 months

• Existing links that reuse BUC/HPA and Antenna– At T1/E1 rates and above, the payback period for modem

replacement is generally within 6 months

– Even at lower data rates, the payback period is generally within 6 – 12 months

• Continues to provide significant OPEX savings after that

26

Typical Applications

• Cellular backhaul• High speed trunking• Offshore

communications• Limited rack space

installations

27

CDM-Qx Overview

• Modular multi-channel satellite modem in 1 RU chassis

• DoubleTalk Carrier-in-Carrier bandwidth compression• Data rates up to 20 Mbps• Viterbi, Concatenated Reed Solomon and 2nd

generation Turbo Product Codes (TPC)• 70/140 MHz or L-Band IF• EIA-422, Sync EIA-232, V.35, HSSI, G.703 (T1/E1)

and Quad-E1 data interface– D&I++ for G.703 E1 & Quad-E1

• Legacy and Standards based monitoring & control• External & Limited Internal redundancy options

28

Architecture

• A CDM-Qx consists of:– A chassis

1 RU size 4-slots per chassis, each

capable of holding a modulator or a demodulator card

Power supply M&C board with EIA-232/485

and 10/100BaseT Ethernet port Tx IF, Rx IF and Ref

– Combination of Modulator and/or Demodulator cards

Data interface Optional TPC encoder/decoder

Power SupplyDigital & IFBackplanes

M&C

4 Slots

Modulator

IF Interface

Note: Quad-E1 requires 2 chassis slots

29

CDM-Qx Chassis

• Valid Configurations (per Chassis) are– 1 to 4 Modulators– 1 to 4 Demodulators– 1 Modem– 2 Modems in 1:1 configuration (i.e. only 1 modem is online at a time)

• DoubleTalk Carrier-in-Carrier license (option)• CDM-Qx: 50 to 90, 100 to 180 MHz

– 75 ohm, BNC– 50 ohm, BNC (option)

• CDM-QxL: 950 to 1950 MHz– 50 ohm, Type-N Female

• Primary power supply– 100-240 VAC or –48 VDC

• BUC Power Supply option (CDM-QxL)• Internal redundancy options for modulator and/or demodulator card

30

DoubleTalk Carrier-in-Carrier Licensing

• Must be configured as a Modem• Requires 1 license per Modem• Available tiers

– Up to 512 kbps– Up to 1 Mbps– Up to 2.5 Mbps– Up to 5 Mbps– Up to 10 Mbps– Up to 20 Mbps– Note: Minimum is 128 ksps for all tiers

31

Special Licensing Rules - 1:1 Internal Redundancy

• Even when a chassis is configured for 1:1 internal modem redundancy, 2 licenses are required

Max Data Rate Required (kbps)

Online Modem License

Backup Modem License

512 kbps 512 kbps 512 kbps

1 Mbps 1 Mbps 1 Mbps

2.5 Mbps 2.5 Mbps 2.5 Mbps

5 Mbps 5 Mbps 2.5 Mbps



32

Demo Mode

• The CDM-Qx supports a Demo Mode which allows users to test the DoubleTalk Carrier-in-Carrier capability

• In the Demo Mode, DoubleTalk Carrier-in-Carrier can be used for up to 45 days– The 45 day countdown timer can be turned ON and OFF as

many times as needed

• Up to 10 Mbps operation on 1st Modem• Up to 2.5 Mbps operation on the 2nd Modem• Up to 10 Mbps operation if used in a 1:1 Internally

Redundant configuration

33

Modulator/Demodulator

• Separate card for Modulator and Demodulator• L-band or 70/140 MHz

– Cannot mix-and-match in a chassis

• Transmit/Receive data rate– Up to 5 Mbps (standard)– Up to 10 Mbps (FAST option)– Up to 20 Mbps (FAST option)– Independently selectable for each Modulator/Demodulator

• Modulation/Demodulation– BPSK, QPSK (standard)– 8-PSK (FAST option)– 16-QAM (FAST option)– Independently selectable for each Modulator/Demodulator

34

Modulator/Demodulator (cont’d)

• FEC Encoding/Decoding– Viterbi (standard)– Concatenated Reed-Solomon (standard)

Comtech (220, 200) EF Data Closed (225, 205) IESS-310 8PSK/TCM (219, 201)

– 2nd Gen TPC Encoder/Decoder card (hardware option) Up to 5 Mbps (included with hardware) Up to 10 Mbps (FAST option) Up to 20 Mbps (FAST option) Each Modulator or Demodulator requires a separate 2nd Gen

TPC Encoder/Decoder card Independently selectable for each Modulator/Demodulator

35

Modulator/Demodulator (cont’d)

• Data interface (hardware selection)– EIA-422/232/V.35 (D25)

EIA-422 up to 12 Mbps V.35 up to 12 Mbps

– HSSI Up to 20 Mbps

– G.703 T1/E1 Balanced (D15)– G.703 T1/E1 Unbalanced (BNC)– Select one per Modem (i.e. Modulator and Demodulator card

combination) OR one per Modulator card and Demodulator card if using independently

In case of “Modem”, only the Demodulator card requires an interface

36

Enhanced D&I++

• Available with G.703 E1 data interface– Supported for E1-CCS only

• Any combination of 1 to 31 time slots can be selected• Simultaneous use of EDMAC and AUPC• Low overhead

– 2.2% including EDMAC and AUPC

• Interoperable with CDM-600/CDM-600L – For up to 24 slots– Viterbi and TPC FEC only

37

Quad E1 Interface (QDI)

• Quad-E1 interface aggregates up to 4 full and/or fractional E1’s into a single satellite carrier– Eliminates multi-carrier backoff for HPA/BUC

Generally 50% or more reduction in HPA/BUC size

– Reduction in number of modems required– Reduction in rack space

• Quad-E1 Module– RJ-45 connector for each E1 (balanced)– Requires 2 slots in the chassis

The other 2 slots must be occupied by a “modem”

38

Quad-E1 Interface (QDI) (cont’d)

• Independent D&I++ For Each E1– Allows for Dropping or Inserting any combination of 1 to 31

Time Slots on each E1– Aggregate, 1 to 128 Time Slots– E1-CCS only

• Very Low Overhead – 0.4%– EDMAC/AUPC overhead is additional (if used)– Extremely efficient compared to 6.67% required by IBS

• Clocking/Synchronization– All 4 E1 must have same clock source

• QDI only interoperates with another QDI at the other end

39

FEC, Modulation & Data Rate Summary (Unframed Operation)

FEC Type Modulation Code Rate Data Rate RangeViterbi BPSK Rate 1/2 32 kbps - 5 MbpsViterbi QPSK Rate 1/2 32 kbps - 10 MbpsViterbi QPSK Rate 3/4 32 kbps - 15 MbpsViterbi QPSK Rate 7/8 32 kbps - 17.5 Mbps

Viterbi + RS (201/219) BPSK Rate 1/2 32 kbps - 4.5 MbpsViterbi + RS (201/219) QPSK Rate 1/2 32 kbps - 9.1 MbpsViterbi + RS (201/219) QPSK Rate 3/4 32 kbps - 13.7 MbpsViterbi + RS (201/219) QPSK Rate 7/8 32 kbps - 16 MbpsViterbi + RS (201/219) 16-QAM Rate 3/4 352.4 kbps - 20 MbpsViterbi + RS (201/219) 16-QAM Rate 7/8 411.1 kbps - 20MbpsTCM + RS (201/219) 8-PSK Rate 2/3 234.9 kbps - 18.3 Mbps

TPC BPSK Rate 5/16 32 kbps - 3.1 Mbps TPC BPSK Rate 21/44 32 kbps - 4.7 MbpsTPC QPSK Rate 21/44 32 kbps - 9.5 Mbps TPC QPSK Rate 3/4 32 kbps - 15 Mbps TPC QPSK Rate 7/8 32 kbps - 17.5 Mbps TPC QPSK Rate 17/18 32 kbps - 18.8 Mbps TPC 8-PSK Rate 3/4 288 kbps - 20 Mbps TPC 8-PSK Rate 7/8 336 kbps - 20 Mbps TPC 8-PSK Rate 17/18 362.7 kbps - 20 Mbps TPC 16-QAM Rate 3/4 384 kbps - 20 Mbps TPC 16-QAM Rate 7/8 448 kbps - 20 Mbps

40

EDMAC and AUPC

• Embedded Distant End Monitoring & Control– Supports EDMAC and EDMAC-2 framing– EDMAC

Interoperable with CDM-600/CDM-600L andCDM-570/CDM-570L

– EDMAC-2 Interoperable with CDM-570/CDM-570L

• Automatic Uplink Power Control– Interoperable with CDM-600/CDM-600L (EDMAC framing)– Interoperable with CDM-570/CDM-570L (EDMAC or

EDMAC-2 framing)

41

Internal Redundancy For Modulator/Demodulator Card(s)

• CDM-Qx can provide redundancy for modulator and/or demodulator card(s) within the chassis without requiring an external switch– 1:1 Redundancy for Modulator & Demodulator card when

configured as a Modem– 1:1, 1:2 or 1:3 Redundancy when using Modulators Only or

Demodulators Only

• It ONLY protects against a failure in the modulator and/or demodulator card

• No protection against failures in Data Interface, M&C module or other common sub-systems in the chassis

• For critical links, use of external redundancy is strongly recommended

42

Management

• CDM-Qx can be managed through– Modem front panel

Menu driven, easy to operate, user interface via keypad and display Nested menus provide access to all M&C functions

– Remote M&C port EIA-232 or EIA-485 operation Remote commands provide access to all M&C functions

– 10/100BaseT Ethernet port Configuration and management using TCP/IP based protocols

– SNMP– Web browser (http)– telnet

Access to all M&C functions

43

M&C Screens (Web Based)

• Modem configuration

44

M&C Screens (Web Based)

• Modulator & Demodulator configuration

45

Spectrum Analyzer Function

• One of the demodulators can be used to view the spectrum or the constellation map– While in this mode, the demodulator is not

available for user data

• Available through a stand alone MS Windows application or a web browser– Windows application can be downloaded from

Comtech EF Data’s web site

46

Spectrum Analyzer (Windows App)

47

Spectrum Analyzer (Web Based)

48

Additional Features

• Rolloff () – 20% and 35%– 20% rolloff can reduce carrier spacing to 1.1 x

Symbol Rate, however it is more susceptible to link impairments compared to 35% Rolloff

• External Redundancy Options– 1:10 redundancy switch

CRS-300-Qx

– 1:1 redundancy switch (April ‘07) CRS-311-Qx

49

Configuration Example 1

• CDM-Qx with DoubleTalk Carrier-in-Carrier to support 1 T1– Chassis – 1

DoubleTalk Carrier-in-Carrier license – 128 ksps to 2.5 Mbps

– Modulator – 1 8-PSK Modulation (if needed) 2nd Gen TPC encoder up to 5 Mbps

– Demodulator – 1 8-PSK Demodulation (if needed) 2nd Gen TPC decoder up to 5 Mbps G.703 T1 Interface – 1

50


• CDM-Qx with DoubleTalk Carrier-in-Carrier to support 4 E1– Chassis – 1

DoubleTalk Carrier-in-Carrier license – 128 ksps to 10 Mbps

– Modulator – 1 8-PSK Modulation (if needed) 2nd Gen TPC encoder up to 10 Mbps

– Demodulator – 1 8-PSK Demodulation (if needed) 2nd Gen TPC decoder up to 10 Mbps

– Quad E1 Data Interface – 1

51


• CDM-Qx with DoubleTalk Carrier-in-Carrier to support 20 Mbps full-duplex, 1:1 internally redundant– Chassis – 1

DoubleTalk Carrier-in-Carrier license – 128 ksps to 20 Mbps (online) DoubleTalk Carrier-in-Carrier license – 128 ksps to 2.5 Mbps (backup) 1:1 redundancy

– Modulator – 2, each with 8-PSK/16QAM Modulation (if needed) 2nd Gen TPC encoder up to 20 Mbps Data rate up to 20 Mbps

– Demodulator – 2, each with 8-PSK/16QAM Demodulation (if needed) 2nd Gen TPC decoder up to 20 Mbps Data rate up to 20 Mbps HSSI interface – 1

52

Conclusions

• CDM-Qx with DoubleTalk Carrier-in-Carrier can– Reduce OPEX– Reduce CAPEX– Increase link availability (i.e. margin)– Increase throughput

• Typical payback period of 0 to 3 months• Significant OPEX savings there after

53

Modem Accessories

• Variety of accessories to enhance the functionality of our satellite modems – 1:1 and 1:N Redundancy Switches – Provides fully automatic

or manual protection of circuits – Performance Enhancement Proxies – Accelerates the TCP

traffic over impaired satellite links – Comtech Monitor & Control System – Provides management of

Comtech EF Data equipment (modems, transceivers, converters and redundancy switches)

– And, more

54

Comtech EF Data

• Delivers global services and support• Specializes in solutions that optimize satellite

communications• Has technologically advanced infrastructure

products installed in more than 160 countries• Provides “around the clock” customer

support • Has authorized service centers around the

world• Is prepared to help you:

– Optimize satellite communications– Minimize operating expenses– Maximize transponder utilization– Lower the total cost of ownership

ADVANCED COMMUNICATION SOLUTIONS

Contact Us:2114 West 7th Street

Tempe, AZ 85281USA

Tel 1.480.333.2200FAX 1.480.333.2540

[email protected]

ADVANCED COMMUNICATION SOLUTIONS CDM-Qx/QxL Satellite Modem with DoubleTalk TM Carrier-in-Carrier ®...

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