iDirect PCMA: Enhancing Bandwidth Efficiency in New and Old Networks

8/20/2019 iDirect PCMA: Enhancing Bandwidth Efficiency in New and Old Networks

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© 2008 VT iDirect, Inc.

PCMA:Enhancing Bandwidth Efficiency in New and Old NetworksNinh Le

Director, Complex Systems Group


2/17

PCMA Saves 15% – 45% on Bandwidth

Without PCMA

Satellite Transponder Spectra

Normalized Frequency Normalized Frequency

P o w e r ( d B )

P o w e r ( d B )

With PCMA

PCMA saves satellite bandwidth by using the same

spectrum for both upstream & downstream carriers.Hughes Network Systems (HNS) makes proprietary Outroute Cancellation

EMC makes COTS (commercial off-the shelf) NRS Bandwidth Booster

ViaSat makes COTS PCMA (Paired Carrier Multiple Access)

Comtech makes COTS DoubleTalk under license from AST


3/17

PCMA Is Easy to Implement

Because It Only Goes at the Hub

Overlapping uplink signal is subtracted to getdesired downlink signal

Downlink =Hub + Remote

-

Remote Hub


4/17

Why Does PCMA Work Best on iDirect Systems and

Not So Well on Other VSAT Systems?

iDirect’s upstream carriers use 100% reservation access

Other VSAT need random access because traffic is often bursty.

Collisions in random access schemes like Slotted Aloha spike power.

20% of TDMA bursts in Slotted Aloha overlap bursts from other remotes.

2 bursts colliding doubles power; 3 bursts colliding triples power; etc.

Power spikes jam downstream, occasionally forcing competing VSAT off net.

iDirect’s 100% reserved upstream avoids power spikes to downstream

Only iDirect’s reservation scheme is responsive enough to carry bursty traffic.

iDirect’s remote terminals all have uplink power control (UPC).

Without UPC, remotes uplink maximum power all the time.

Maximum power typically contains 2-3 dB of extra power for rain fade andanother few dB of extra power for differences in G/T contour.

Every dB of extra uplink power at any remote is a dB of unnecessaryinterference to the downstream carrier.

Downstream facing more interference needs more transponder power or aless efficient MODCOD to overcome the extra (unnecessary) interference.

UPC minimizes upstream power interfering with downstream carrier.

UPC makes all remotes hit satellite with the same (minimum) flux density.

No unnecessary interference = maximum efficiency.


5/17

When Should iDirect Bring Up PCMA as a Topic?Obvious Situations

When new bandwidth is not available for new projects, PCMAfrees up existing bandwidth for use by new iDirect VSAT.

When low margin projects need cost cuts to be viable, PCMA cutsoperating costs, especially for bandwidth intensive apps.

For Evolution, PCMA saves the most BW in 3:1 asymmetric networks.

iNFINITI best in networks too small for DVB-S2’s min (2-3 MHz) scale.

For iNFINITI networks…

PCMA cuts operating costs by the same amount as LDPC from DVB-S2

PCMA upgrade takes less time, work, & money than DVB-S2 upgrade


6/17

When Should iDirect Bring Up PCMA as a Topic?Payback Calculator for Obvious Situations

DS IP Data Eff ic iency 1 .29 bi ts /sec/HzUS IP Data Effici ency 0.8 bits/sec/Hz

Satelli te BW Cost 5,000 $/MHz/Month

IFL Frequency L-Band

1:1 PCMA Redundancy YesFrequency Converters Yes

Installation Services Yes (Frequency Converters)SkyMonitor No

Installation Services No (SkyMonitor)

US IP Data

Throughput,

Mbps

Payback

Period,

Months

Additional

Revenue,

%

US IP Data

Throughput,

Mbps

Payback

Period,

Months

Additional

Revenue,

%

US IP Data

Throughput,

Mbps

Payback

Period,

Months

Additional

Revenue,

%

US IP Data

Throughput,

Mbps

Payback

Period,

Months

Additional

Revenue,

%

US IP Data

Throughput,

Mbps

Payback

Period,

Months

Additional

Revenue,

%

0.50 0.50 31 62.0% 0.33 33 80.4% 0.25 47 57.1% 0.17 79 33.7% 0.13 120 22.0%

1.00 1.00 16 62.0% 0.67 17 80.4% 0.50 24 57.1% 0.33 40 33.7% 0.25 60 22.0%2.00 2.00 8 62.0% 1.33 9 80.4% 1.00 12 57.1% 0.67 20 33.7% 0.50 30 22.0%3.00 3.00 6 62.0% 2.00 6 80.4% 1.50 8 57.1% 1.00 14 33.7% 0.75 20 22.0%4.00 4.00 4 62.0% 2.67 5 80.4% 2.00 6 57.1% 1.33 10 33.7% 1.00 15 22.0%5.00 5.00 4 62.0% 3.33 4 80.4% 2.50 5 57.1% 1.67 8 33.7% 1.25 12 22.0%

6.00 6.00 3 62.0% 4.00 3 80.4% 3.00 4 57.1% 2.00 7 33.7% 1.50 10 22.0%

7.00 7.00 3 62.0% 4.67 3 80.4% 3.50 4 57.1% 2.33 6 33.7% 1.75 9 22.0%8.00 8.00 2 62.0% 5.33 3 80.4% 4.00 3 57.1% 2.67 5 33.7% 2.00 8 22.0%9.00 9.00 2 62.0% 6.00 2 80.4% 4.50 3 57.1% 3.00 5 33.7% 2.25 7 22.0%

10.00 10.00 2 62.0% 6.67 2 80.4% 5.00 3 57.1% 3.33 4 33.7% 2.50 6 22.0%

15.00 15.00 2 62.0% 10.00 2 80.4% 7.50 3 57.1% 5.00 4 33.7% 3.75 6 22.0%20.00 20.00 2 62.0% 13.33 2 80.4% 10.00 2 57.1% 6.67 3 33.7% 5.00 5 22.0%25.00 25.00 1 62.0% 16.67 1 80.4% 12.50 2 57.1% 8.33 3 33.7% 6.25 4 22.0%30.00 30.00 1 62.0% 20.00 1 80.4% 15.00 2 57.1% 10.00 3 33.7% 7.50 4 22.0%35.00 35.00 1 62.0% 23.33 1 80.4% 17.50 2 57.1% 11.67 2 33.7% 8.75 3 22.0%

PCMA Payback Period and Additional Revenue Calculator

Satellite Links Paramaters

Hub Equipment Configuration

Downstream IP Data

Aggregate

Throughput,

Mbps

4 : 1

DS-to-US Link Asymmetry

1 : 1 1.5 : 1 2 : 1 3 : 1


7/17

When Should iDirect Bring Up PCMA as a Topic?Less Obvious Situations

When competing against Comtech’s CDM-QxL modems, PCMAmakes iDirect’s SCPC modems comparable in BW efficiency.

PCMA expands iDirect’s addressable GSM market to thicker trunks.

In SCPC applications, both sides of a link need a PCMA canceller.

To afford PCMA at all sites, iDirect needs L-band PCMA canceller.

ViaSat should deliver first L-band PCMA cancellers in Q2 of 2009.

When special access is required for the return channel…

PCMA hides upstream carriers from detection

PCMA makes bandwidth for spread spectrum carriers affordable


8/17

iDirect Hub with PCMA and Quintech Converters

iDirect

Hub P C M A

C a n c e l l e r

Frequency

(Up)

Converter

1

RXRX

OutRX

InIFL

Out

IF

InIF

OutIFL

In

L Band

70 MHz BNC F

LNB

Rx

Power In

Nominal: -25dBm

Min: -65dBm

Max: -5dBm

Power In

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

Power OutNominal: -25dBm

Min: -50dBm

Max: -20dBm


Min: -50dBm

Max: -20dBm

Power In

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

TXTX

In

TX

Out

Frequency

(Down)

Converter

2IFL

In

IF

Out

IF

InIFL

Out

HPA

Tx

Power Out

Nominal: -25dBm

Min: -35dBm

Max: +7dBm

Power Out

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

Power In

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

Power In

Nominal: -25dBm

Min: -30dBm

Max: +10dBm

Power Out

Nominal: -25dBm

Min: -35dBm

Max: -5dBm

Power In

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

Power Out

Nominal: -25dBm

Min: -50dBm

Max: -20dBm

L-band

CenterFrequency

70

MHz CenterFrequency

70

MHz CenterFrequency

L-band

CenterFrequency

L-band

Center

Frequency

70

MHz Center

Frequency

70

MHz Center

Frequency

L-band

Center

Frequency

Frequency

(Up)

Converter

4

Frequency

(Down)

Converter

3

Power In

Nominal: -25dBm

Min: -30dBm

Max: +10dBm


Min: -35dBm

Max: -5dBm


9/17

iDirect Will Sell PCMA Cancellers at List Price

PCMA Packages from iDirect Frequency Converters Option

Single Amount of MSRP for Mandatory Minimum Frequency FrequencyThread or Cancellation PCMA Professional PCMA Converters ConvertersRedundant (MHz) Appliance Services Packages for L-band IFL for 70 MHz IFL

Single Thread 2 12,499$ 9,000$ 21,499$ 7,320$ 3,660$Single Thread 5 15,999$ 9,000$ 24,999$ 7,320$ 3,660$Single Thread 10 24,999$ 9,000$ 33,999$ 7,320$ 3,660$Single Thread 20 37,499$ 9,000$ 46,499$ 7,320$ 3,660$Single Thread 36 49,999$ 9,000$ 58,999$ 7,320$ 3,660$1:1 Redundant 10 42,498$ 9,000$ 51,498$ 7,320$ 3,660$1:1 Redundant 20 63,748$ 9,000$ 72,748$ 7,320$ 3,660$1:1 Redundant 36 84,998$ 9,000$ 93,998$ 7,320$ 3,660$

Frequency Converters from Quintech deliver best phase noise value.Technical Support Charges after the Sale: as per standard iSupport fees.Mandory Professional Services: 3.5 days including travel and expenses.

Link budget analysis to quantify bandwidth savingsDesign of PCMA networkPre-installation coordinationInstallation of PCMA Canceller

Acceptance Testing, Training, and Documentation


10/17

Operational Considerations

Necessary Link Conditions

Duplex circuits only (symmetric or asymmetric inroute + outroute)Loopback transponder to receive own uplink signal. No cross-strap Xpdr.

Nice to Have: Factors that Make PCMA More Efficient

Cancellation at Both Sides of Each SCPC Link (Comtech CDM-QxL)

Large Hub Antennas

5+ meter Ku-band antenna

7+ meter C-band antenna

More Powerful Satellite Transponders

48+ dBW EIRP for 36 MHz Ku-band transponders

38+ dBW EIRP for 36 MHz C-band transponders

Lower Link Availability

99.0% or lower end-to-end availability for Ku-band links99.7% or lower end-to-end availability for C-band links

Lower SNR (signal to noise ratio) Thresholds

Better FEC coding (LDPC vs. TPC)

Lower MODCOD’s (BPSK and QPSK vs. 8PSK and 16APSK)

Asymmetric downstream:uptream traffic (1:1 to 3:1 asymmetry is best)


11/17

Operational Considerations

Required Changes in Network Operating Processes

Need one upstream carrier outside PCMA to bring in new VSATCW to peak BUC power at new remote must be done outside PCMA

CW jams shared downstream. Never overlay CW on downstream.

Bring remotes into network at low initial transmit powerLet UPC slowly lift dBm from below SNR threshold to optimal SNR

This acquisition process takes more time than starting at high dBm

Geographic redundancy in iDS 7.0 or later software is neededEach remote in a PCMA network should have 2 networks configured

Primary configuration is the network as it should be with PCMA

Second configuration uses the same spectrum for unpaired carriers thatremotes can fail over to if normal PCMA operations are ever disrupted

To prevent jamming from inter-symbol interference, symbol rates ofpaired carriers cannot be within 5% of each other.

UPC must target no more than SNR threshold + 0.5 dBUpstream SNR 0.5 dB beyond SNR threshold harms downstream

Fine UPC adjustments needed when SNR within ± 0.5 dB of target

Downstream PEB + Upstream PEB ≤ Allocated PEB Downstream carrier typically 0.1 to 0.5 dB bandwidth limited

0.1 to 0.5 dB of total power typically used for upstream carrier


12/17

PCMA Link Budget Analysis: Additional Interference to Downstream Carrier


13/17

PCMA Link Budget Analysis: Additional Interference to Upstream Carrier


14/17

PCMA Link Budget Analysis:Math to Quantify Additional Interference to Both Downstream and Upstream Carriers

1

SNReffective

= Σ 1

SNRii = 1

n

Note: SNR above must be quantified in power ratios, not dB’s.

dB SNR = 10 x log( ) Watts of Signal

Watts of Noise

Therefore, in the first equation above…

SNRi = 10(dB SNR)÷10


15/17

PCMA Link Budget Analysis:Spread Sheet to Quantify Interference to Both Downstream and Upstream Carriers

DownstreamLBA

Upstream

LBA

+

PCMA Downstream Interference AnalysisUnits

Carrier/Link ParametersModulation 4-PSK 2 bits/symRequired Eb/No with FEC coding 5.9 dB

FEC code rate 0.6284

Clear Rain over Rain over

Sky Hub VSAT

PCMA Totals per carrier (End-to-End)

C/(N+I) without upstream interference 12.01 12.01 11.52 dB

Downstream satellite power density -40.44 -40.44 -40.44 dBW/HzUpstream satellite power density towards VSAT -48.96 -48.96 -49.18 dBW/Hz

C/USI (UpStream Interference) 8.52 8.52 8.74 dBC/(N+I) with upstream interference 6.91 6.91 6.90 dB

Required C/(N+I) 6.89 6.89 6.89 dBSystem Margin 0.02 0.02 0.01 dBC/(N+I) degradation due to upstream interference 5.10 5.10 4.62 dB

PCMA Upstream Interference AnalysisUnits

Carrier/Link Parameters

Modulation 4-PSK 2 bits/symRequired Eb/No with FEC coding 8.2 dB

FEC code rate 0.793PCMA cancellation 27 dB

Clear Rain over Rain over Sky Hub VSAT

PCMA Totals per carrier (End-to-End)

C/(N+I) without downstream interference 11.20 10.90 10.99 dBUpstream satellite power density -48.96 -48.96 -49.18 dBW/Hz

Downstream satellite power density towards Hub -40.44 -40.44 -40.44 dBW/HzC/DSI (DownStream Interference) 18.48 18.48 18.26 dB

C/(N+I) with downstream interference 10.46 10.20 10.24 dBRequired C/(N+I) 10.20 10.20 10.20 dB

System Margin 0.25 0.00 0.04 dBC/(N+I) degradation due to downstream interference 0.74 0.70 0.75 dB


16/17

Additional Considerations for Saturated Transponder:1.5 dB OBO and 1 dB Extra Upstream Eb/No Threshold Are Recommended

Downstream Downstream Downstream Downstream Downstream Downstream SNR DownstreamOutput Backoff MODCOD HPA Uplink Pwr Av. SCPC Errors SNR Threshold at 9m Antenna EIRP at Hub(dB) (Watts) (Packets/20sec) (dB) (dB) (dBW)

0.0 8PSK rate 5/6 45.7 0 10.6 14.3 49.30.5 8PSK rate 5/6 40.3 0 10.6 13.3 48.91.0 8PSK rate 5/6 37.8 0 10.6 13.4 48.41.5 8PSK rate 5/6 30.5 0 10.6 12.0 47.91.5 8PSK rate 5/6 30.8 0 10.6 13.8 47.92.0 8PSK rate 5/6 26.1 0 10.6 13.0 47.42.5 8PSK rate 5/6 24.1 0 10.6 12.5 46.93.0 8PSK rate 5/6 21.9 0 10.6 12.4 46.41.0 8PSK rate 5/6 37.6 0 10.6 14.2 48.41.0 8PSK rate 5/6 37.6 0 10.6 14.1 48.41.0 8PSK rate 5/6 37.6 0 10.6 14.1 48.4

1.0 8PSK rate 5/6 37.6 0 10.6 14.0 48.41.0 8PSK rate 5/6 39.0 0 10.6 12.9 48.51.5 8PSK rate 5/6 30.8 0 10.6 12.3 47.9

Downstream Upstream VSAT Modem Upstream Upstream SNR SNR of TDMA SNR of TDMA Upstream TotalOutput Backoff MODCOD Power to BUC Av. CRC Errors Threshold Carrier Inside Carrier Outside Baud Rate(dB) (dBm) (Bursts/20sec) (dB) PCMA Spectrum PCMA Spectrum (Msps)

0.0 QPSK rate 0.66 -10 0 6.1 9.0 9.5 1.5360.5 QPSK rate 0.66 -10 0 6.1 12.0 12.5 1.5361.0 QPSK rate 0.66 -10 0 6.1 12.3 13.4 1.536

1.5 QPSK rate 0.66 -10 0 6.1 14.0 14.5 1.5361.5 QPSK rate 0.66 -17 0 6.1 6.7 7.1 1.5362.0 QPSK rate 0.66 -17 0 6.1 8.2 8.6 1.5362.5 QPSK rate 0.66 -17 0 6.1 8.6 8.7 1.5363.0 QPSK rate 0.66 -17 0 6.1 8.9 8.9 1.5361.0 QPSK rate 0.66 -17 20 6.1 5.5 5.0 1.5361.0 QPSK rate 0.66 -16 0 6.1 6.0 6.4 1.5361.0 QPSK rate 0.66 -15.5 0 6.1 6.5 6.4 1.5361.0 QPSK rate 0.66 -15 0 6.1 7.0 7.0 1.5361.0 QPSK rate 0.66 -15 0 6.1 6.2 6.8 27.5121.5 QPSK rate 0.66 -15 0 6.1 8.3 9.7 27.512


17/17© 2008 VT iDirect Inc

Conclusion:

PCMA can give iNFINITI VSAT the efficiency of DVB-S2.

PCMA can boost the efficiency of DVB-S2 even further.

Documents

iDirect PCMA: Enhancing Bandwidth Efficiency in New and Old Networks