Satellite Network Dimensioning

Satellite Network Dimensioning
Andreas Spoormaker Director Customer Solutions Engineering-Intelsat Africa 1

Agenda Service Level Elements Common Satellite Network Technology
Economics – Cost of Ownership Which Solution is Best for My Network? Link Optimization Initiatives

Agenda Service Level Elements Satellite Network Technology Options
Economics - Cost of Ownership Which Solution is Best for My Network? Link Optimization Initiatives 3

Service Level Elements (1)
Example 1Mbps service descriptions… 1Mbps dedicated outbound / 1Mpbs dedicated inbound 1Mbps dedicated outbound / 256kbps dedicated inbound 1Mbps shared (5:1) outbound with 256kbps CIR / 256kbps shared (5:1) inbound with 32kbps CIR 1Mbps shared (10:1) outbound with 128kbps CIR / 256kbps shared (10:1) inbound with 16kbps CIR 1Mbps shared (25:1) outbound with no CIR / 1Mbps shared (25:1) inbound with no CIR etc… ...many potential scenarios  Need to clearly specify requirement! Not all “1 Mbps services” are created equal. I usually ask the crowd to imagine in their mind what a “1 Mbps service” is then comment that there are probably N different definitions (N being the number of people in the audience). The main point is that one has to dig into a customer’s expectations to understand what a customer is asking for and not use a cookie-cutter approach to rolling out services to multiple customers… An underlying point is that the underlying cost of the services above are all quite different. 4

Service Level Elements (2) IP Layer
Common Service Level criteria at IP Layer: Committed Information Rate (CIR) (min/max for ACM) Burstable Information Rate (BIR) Oversubscription Ratio (X:Y) Quality of Service (application, VoIP, Diffserv, etc…) These are the most talked-about concepts of service level, in descending order. Many only talk of the first. (next slide kills the concept that this is the only thing that matters) CIRs are needed to provide a guaranteed amount of bandwidth to a site. The BIR is the datarate to which a site can reach, if bandwidth is available. Oversubscription is used by service providers to get to the price point that an end user requires (since the cost basis is fixed). Quality of Service is fourth most-talked about. This is what allows voice prioritization over video, some types of data over other types of data, etc. 5

Service Level Elements (3) IP Layer
Network Dimensioning Considerations: Supported applications Number of users and locations Traffic per user/group Latency (terrestrial, access protocol, propagation ≈260ms, hub processing) Response time Scope for growth/expansion of network These are the most talked-about concepts of service level, in descending order. Many only talk of the first. (next slide kills the concept that this is the only thing that matters) CIRs are needed to provide a guaranteed amount of bandwidth to a site. The BIR is the datarate to which a site can reach, if bandwidth is available. Oversubscription is used by service providers to get to the price point that an end user requires (since the cost basis is fixed). Quality of Service is fourth most-talked about. This is what allows voice prioritization over video, some types of data over other types of data, etc. 6

Service Level criteria can only be met if following ensured: Latency (delay) Jitter (real-time packet Rx) BER Link Availability Downtime …SLA’s carry underlying commercial penalties for non-performance… These are the elements that are not discussed out loud. But these are the elements that are in contracts…. And carry monetary penalties for non-performance. I bring this up here since I touch upon concepts that optimize each. The idea is that these concepts must be addressed and ensured of first before the concepts on Slide 4 can be considered. All of these are based on Layer 1 (RF) performance. One must focus on maintaining a solid Layer 1 connection before placing focus on Layer 2 (TDMA vs. SCPC) and on Layer 3 (IP, QoS, etc.). 7

Satellite network is one component of end to end service Need to dimension satellite network to ensure performance criteria met Efficient delivery to remote sites Efficient inbound access method (to support CIR, BIR) Intelsat customers can deliver against SLA (to their end customers) These are the elements that are not discussed out loud. But these are the elements that are in contracts…. And carry monetary penalties for non-performance. I bring this up here since I touch upon concepts that optimize each. The idea is that these concepts must be addressed and ensured of first before the concepts on Slide 4 can be considered. All of these are based on Layer 1 (RF) performance. One must focus on maintaining a solid Layer 1 connection before placing focus on Layer 2 (TDMA vs. SCPC) and on Layer 3 (IP, QoS, etc.). 8

… sufficient margins must be included to ensure link integrity …
The Satellite Link … sufficient margins must be included to ensure link integrity …

Necessary Inputs to Determine Proper Solution
Satellite Frequency Band Hub Antenna Size Hub Location Remote Antenna Size Remote Locations Service Level Latency, Jitter, etc. Availability, Downtime, etc. Voice Traffic Number of VoIP Lines % Usage on Average % Usage Maximum Data Traffic CIR BIR Oversubscription Ratio Video Traffic Quality Quick answer …. It Depends. CEFD cannot guarantee that our solution is best, nor can anyone else. We can’t say that 5-50 sites is CEFD, 50 sites plus is TDMA. We take pride in sizing a network properly and helping a service provider make their decision intelligently. Give us a shot and we’ll tell you what’s best. Talk up Sales Engineering (because we’re great). We’ll tell you if we are not a good fit. 10

Economics - Cost of Ownership Which Solution is Best for My Network? Link Optimisation Initiatives 11

Satellite Access Technologies
Hub platform supporting delivery to multiple sites via shared outbound Dedicated or shared inbound, depending on service requirements/platform 12

Satellite Access Technologies Outbound (TDM, DVB-S2, etc.)
Hub-based shared mechanism IP Packet Switching over an MCPC Carrier TDM combines multiple data streams/packets using variable time slot lengths Statistical multiplexing allocates bandwidth on an as-needed basis using different statistical decision criteria Much tighter IP packet transmission than a remote shared mechanism (TDMA, DVB-RCS, etc.) – reduced overhead Some version of TDM used for the outbound carrier of most every satellite point-to-multipoint network solution TDM is a bad name for this since the connotation of TDM is a fixed frame and slot size. While DVB-S2 uses a fixed frame and slot size, proprietary HDLC’s use a variable frame and slot size. Each satellite network solution uses a “TDM” for its outbound carrier. Stat muxing allows CIRs and BIRs via QoS. 13

Satellite Access Technologies Inbound (TDMA, DVB-RCS, etc.)
Allows multiple remotes to access shared medium in an organized fashion Access control is required Reference bursts Timing references for all stations to allow proper burst interleaving within TDMA frame Guard time Transmit timing accuracy and range rate variation of satellite Traffic burst One remote at a time Detailed traffic plan is calculated and disseminated One or many slots per burst One remote per slot Media access control is needed for any shared medium. All remotes are geographically dispersed and because of this, each remote must coordinate its transmission plan to ensure that its bursts arrive at the satellite at the same time. As a satellite moves, this transmission plan changes. As different requests are made for more bandwidth, the transmission plan changes. Guard times are needed to ensure that packets to not interleave when received at the satellite. A frame of fixed size is divided into slots of fixed size. The number of slots per frame is a function of the FEC rate. The point is that a slot can only be assigned to a single remote. If a remote doesn’t need a whole slot, the rest of it is wasted. 14

Satellite Access Technologies Inbound (SCPC)
Single Channel per Carrier provides the ability for one remote to access the same medium at a time in a non-contended fashion No sharing of bandwidth between remotes within the medium itself No concept of a timeframe as packets are tightly packed without concern of contention No access control required Associated overhead eliminated All “bursts” are traffic, one after another not overhead Each site has a fixed amount of bandwidth available to it at all times No contention, in general, is good. No contention can also be bad (let’s be fair) if remotes really need only a small fraction of bandwidth on average. There is no concept of a fixed frame and associated fixed slots with SCPC. 15

Single Channel Per Carrier
TDM/MF-SCPC Model Single Channel Per Carrier Advantage Disadvantage Dedicated bandwidth for each remote inbound Each remote requires its own space segment Provides superior Quality of Service for critical applications Expensive OPEX if each remote bandwidth is not fully utilized Low Latency and Low Jitter SCPC modems typically more expensive than TDMA modems Best transmission method for real-time applications, voice, data, video, broadcast, etc. Fixed data rates on the inbound links This topology is very similar to the all SCPC point-to-point concept, with the exception that a shared outbound link is used. The outbound is not a TDM but rather an MCPC (multi channel per carrier) This is similar to what “others” do. TDM is sized for worst-case site. Advantage of SCPC is that it’s always on. Disadvantage of SCPC is that it’s always on. (more on this later … dynamic SCPC). This is not a good model for best-effort service. The inbound links in this model can be sized per remote. Perhaps remotes at the edge are lower mod/FEC while remotes at beam center are higher mod/FEC. These latter remotes need not be overburdened by the worst-case site. 16

Time Division Multiple Access
TDM/MF-TDMA Model Time Division Multiple Access Advantage Disadvantage Sharing of satellite bandwidth Increased Latency and Jitter Lower overall OPEX compared to dedicated pipes Demanding remotes can burden the system Good for low data rate applications Fragmentation of packets. Less effective for voice and video Low cost remotes Expensive hub equipment Large population of users All remotes must be designed around worst case link The advantage of TDMA is the sharing. A single carrier can support many remotes. The disadvantage of TDMA is the sharing. As multiple remote sites all access the same medium, reference bursts, guard bands, etc. are required. For best-effort services, this model can’t be beat. Low cost remotes help bring down the price per month of those best-effort services to $100-$250 per month, even for 1 Mbps services. Great for 1000’s of sites at low prices. 17

Economics - Cost of Ownership Which Solution is Best for My Network? Link Optimisation Initiatives Now that we have covered service levels and the different options available to meet these, let’s look into the underlying costs of providing a service. 18

Satellite Network Economics “Cost of Ownership”
Operating Expenses (OPEX) Satellite space segment Teleport operations Licensing Capital Expenses (CAPEX) Remote Indoor Kit Outdoor Kit Hub Equipment Ground equipment, routers, switching equipment Converters, RF, HPA, antennas Operating Expenses Site Rental Operations & Maintenance Power Transmission OPEX Spares/Support Training Capital Expenses Transmission Equipment When rolling out a service, whether that be over 2, 3, 4 years or more, service product managers must determine what the total cost of the service will be to determine the price of the service with profit margin targets forming its basis. Usually, focus is placed on the price of the remote modem only. This is part of the story, but only Chapter 1. Chapter 2 concerns the rest of the remote kit, including the ODU and antenna. Chapter 3 concerns the hub. Not only the “starter kit” but also the growth costs (more inbound links, more hardware, etc.). Six chapters, 4-10, are required to cover the amount of space segment required. At $5,000 per MHz per month, this can be significant. Only after the costs of each satellite network topology option are calculated can one determine what the proper solution is. So let’s dive in…. Network Equipment Civil Works Site Equipment NRO Network Operations + Depreciation Total Cost of Ownership 19

Mbps vs. MHz Actual Information Control Addressing * Guard Band *
Data Actual Information Modulation Layer 2 O/H Control Addressing * Guard Band * Reference Bursts * FEC Layer 2 O/H Data Mbps Bullseye concept. Work your way out. FEC Added Redundancy Modulation Bits/Hz 20

Mbps vs. MHz Revenue and Cost Bases
Modulation …Service REVENUE based upon IP Rate in Mbps… FEC Layer 2 O/H …Main OPEX cost based upon total MHz required… Data Mbps Data (Black) is the revenue. Green is the total cost. An end user’s service level requirements and per-site price points will determine what realistic margins may be achievable… 21

Satellite Access Technologies (Info Rate vs. IP Rate)
Two different data rates are important when sizing a TDMA network… IP Rate and Information Rate IP Rate is the actual IP throughput including IP headers and data at Layer 3 of the OSI model Represents actual LAN traffic on both remote and hub LANs Information Rate is the actual Layer 2 information, including TDMA framing overhead, sent over the satellite Link budgets must account for Information Rate, not IP Rate Different platforms have different IP Rate / Information Rate ratios Depends on satellite access method aloha, slotted aloha (minimum delay, low traffic), TDMA There are two very different data rates, IP and Info. IP Rate is what is sold. Information Rate is what link budgets are run on. What is important in calculating total space segment required is the ratio of IP Rate to Information Rate. The higher the ratio, the more efficient the use of space segment. 22

Forward Error Correction Turbo Product Coding (TPC)
Iterative decoding process Process produces a likelihood and confidence level measure for each bit Two parallel decoders “collaborate” and reach joint decision on bit value Low latency (vs. TCC, Vit/RS) Due to the fact that there is no need to buffer for interleaving Turbo Product Coding Lower Eb/No requires less power Higher efficiency requires less bandwidth Ten years or so ago, a new FEC method that takes that best-guess concept further. Via increased intelligence and iterative nature, TPC allows a signal to be sent via a much lower power level. Less BW Less Power Viterbi / RS TPC

Low Density Parity Check (LDPC)
Basis of DVB-S2 standard (LDPC/BCH) Third-class of Turbo Code Turbo Product Coding (TPC) Turbo Convolutional Coding (TCC) Iteratively decoded block code Performs 0.7 dB – 1.2 dB better than TPC at low FEC rates (3/4 and below) While coding gain is greater, processing delay can be an issue The new kid on the block, LDPC. The guys of DVB-S2. Along the no-free-lunch path, the last bullet item should minimize pushback on LDPC. The larger block size of LDPC requires a longer amount of time to fill up a block, decode and transmit. VersaFEC, due in early 2009 will be a small-block LDPC with RF performance of LDPC with latencies of TPC. At 2 Mbps and above, latency is not an issue since each block is filled up quickly, decoded and transmitted. Below 2 Mbps, VersaFEC will provide significant improvements to delay numbers. We can’t provide anything in writing on VersaFEC. If asked, just tell folks to keep their ears open. 24

Spectral Efficiency vs. Eb/No
It is the job of the vendor to get the industry closer to the Shannon Limit to utilize the very scarce space segment resource in the most efficient manner (thereby helping the entire industry). Mix of bandwidth and power. The best spectral efficiency at the lowest Eb/No level. Source : Comtech EF Data 25

Benefits of Forward Error Correction
Advances in FEC can offer ≥ 3-5 dB of performance 3 dB of Coding Gain can: Reduce required bandwidth by 50% (OPEX) Increase data throughput by a factor of 2 (OPEX) Reduce antenna size by 30% (CAPEX) Reduce transmitter power by a factor of 2 (CAPEX) Provides more link margin (Service Level) So what?? Let’s put it into $$ Reduced bandwidth .. (significant decrease in OPEX). Increased datarate .. or lower oversubscription rate or twice the CIR or twice the BIR within the same space segment resource. (higher service level) Reduced antenna size .. maybe a 1.8M instead of a 2.4M, maybe a 1.2M instead of a 1.8M, etc. (significant CAPEX savings) Reduced transmitter power .. maybe a 10 W instead of a 20 W, maybe a 4 W instead of a 8 W, etc. (significant CAPEX savings) Or better link margin (no bullet) to allow a higher service level. 26

Bandwidth vs. Power Balanced Allocated BW/PEB Allocated BW
Transponder bandwidth actually used Linear function of modulation and FEC Decreases with higher order mods and FECs “Bandwidth Limited” links have greater allocated BW compared to PEB Power Equivalent BW Transponder power required to close link Complicated function of hub antenna, remote antenna and satellite specifics along with required Eb/No Increases with higher order mods and FECs “Power Limited” links have greater PEB compared to allocated BW A satellite operator is going to charge for the greater of the two. A conversation about one of these and not the other is not a full conversation. Balanced Allocated BW/PEB 27

CAPEX (Hub Hardware) Two models of hub hardware cost assignment
Per project Over multiple projects Hub platform costs can introduce significantly high barriers to entry Lower cost hubs have lowered this barrier Virtual Network Operator (VNO) concept lowered this entry cost Growth costs must also be considered Function of how many end customers a “starter kit” can support Equipment re-use Some platforms use the same hardware for hub and remote Hub costs can be significant. Some concepts (such as VNO) have lowered the barrier to entry. 28

CAPEX (Remote Hardware)
Remote costs can become significant part of the total cost of a network Portion of TCO grows with the size of the network Indoor Kit Low-cost TDMA/DVB-RCS Indoor Units (IDUs) have dropped in price to $1,000 SCPC modems $4,000+ Outdoor Kit Antenna and ODU sizing based on either shared carrier size or dedicated carrier size Example  1024 kbps TDMA inbound carrier with each remote requiring a 256 kbps service The remote IDU is only part of the cost. Each site in a TDMA network must be sized for worst-case site. 29

CAPEX (Remote Hardware) TDMA vs. SCPC
Here’s an example of possible CAPEX savings using the previous example. ODU requirements  TDMA site requires ~30% more power Bandwidth requirements  SCPC site requires ~53% more BW Avg. CIR  256kbps vs. 512kbps (TDMA vs. SCPC) 30

Here’s an example of possible CAPEX savings using the previous example. ODU requirements  TDMA site requires ~160% more power Bandwidth requirements  SCPC site requires ~53% more BW Avg. CIR  256kbps vs. 512kbps (TDMA vs. SCPC) 31

Here’s an example of possible CAPEX savings using the previous example. ODU constant  Higher mod and/or FEC possible with SCPC Hub CAPEX constant in SCPC model, variable with TDMA Ratio of Avg. CIR / BIR will determine best solution 32

So Which Solution is Best??
TDM / MF-TDMA TDM / MF - SCPC One Cannot Determine… 34

So Which Solution is Best??
Satellite Frequency Band Hub Antenna Size Hub Location Remote Antenna Size Remote Locations Service Level Latency, Jitter Availability, Downtime Voice Traffic Number of VoIP Lines % Usage on Average % Usage Maximum Data Traffic CIR BIR Oversubscription Ratio Video Traffic Quality Until These Are Known… Quick answer …. It Depends. CEFD cannot guarantee that our solution is best, nor can anyone else. We can’t say that 5-50 sites is CEFD, 50 sites plus is TDMA. We take pride in sizing a network properly and helping a service provider make their decision intelligently. Give us a shot and we’ll tell you what’s best. Talk up Sales Engineering (because we’re great). We’ll tell you if we are not a good fit. … only with this information can one make the proper decision… 35

Link Performance Optimization
Intelsat support to optimise throughput / service delivery: Optimized link analysis (LST-5, STRIP7, IOO) Beam/txp/carrier allocation to optimise outbound/inbound performance In-house evaluation of hardware (managed service portfolio)  operating conditions (e.g. IESS, 16APSK DVB-S2, CCT) VNO – traffic optimization (iDirect) 37

Network Dimensioning Link Budget Satellite Parameters Orbit Location
Coverage Footprint Frequency band Transponder Op Mode Customer Requirements CIR/BIR/oversubscription/QoS VoIP traffic profiles Video/data profile Latency, Jitter etc. IP/Information Rate BER Availability Dimensioning Satellite Bandwidth Txp Operating Point Hub/Remote Antenna HPA Size Link Performance Link Budget Network Architecture Number of carriers Access type (Outbound/Inbound) Modulation, Coding

Satellite Parameters – Footprint Data
Technical User Guides (TUG) – Footprint Data (IS-902/62°E) Transponder, Connectivity, etc.

Link Optimization LST5 link budget tool STRIP7, OFPS (Intelsat)
8PSK/8QAM, 16QAM, 16APSK ACM - maximize throughput under dynamic link conditions (SLA) LDPC (incorporated into LST5) CCT optimization algorithm soon (guidance on interim LST-5 approach)

16APSK Operation Detailed testing of Newtec Elevation DVB-S2 modulator to determine practical operating conditions for 16APSK under multicarrier txp / saturated txp scenarios With pre-correction No pre-correction – assessment of HPA OBO for TWTA, linearized TWTA, SSPA Implications for general DVB-S2 platforms

16APSK Operation No significant impact for use of linear pre-correction for group delay/frequency response for multi-carrier transponder Require non-linear pre-correction to compensate for amplitude and phase distortions associated with operation near transponder saturation Uplink HPA assumed to operate multi-carrier OBO Requires transponder characteristics (freq response, group delay, AM/AM, AM/PM) Newtec calculation of pre-distortion data (approx. 24 hours) Load data into Newtec modulator

Comtech Double Talk Carrier-in-Carrier

Comtech Double Talk Carrier-in-Carrier
Teleport Loopback test

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