1. Confidential and proprietary information
This presentation constitutes proprietary and confidential information of Gilat Satellite Networks Ltd. This presentation may
not be disclosed, used or duplicated, in whole or in part, without the prior written consent of Gilat Satellite Networks Ltd.
SkyEdge-II Accent
2. Confidential and proprietary information
TDMA or SCPC?
● TDMA operation (Burst Mode) has advantages over SCPC
● Better bandwidth efficiency in dynamic environments
● Better Management of remote sites
● Adaptive outbound and inbound
● Continuous operation (SCPC) has advantages over bursts:
● Continuous traffic (high activity ratio), where DAMA does not
bring benefits
● Need high throughput in given antenna size – SCPC has
better performace
● Applications: Backup for terrestrial lines; Video or file upload; PoP (ISP/
cyber café) or very large enterprise site; High capacity cellular backhaul
sites; On-the-Move small antennas (mandates the better Eb/N0)
Demand Assigned Multiple Access(DAMA) x Single channel per carrier x Time division multiple access
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3. Confidential and proprietary information
Case study; African ISP
● Using SkyEdge II to connect government and
enterprise customers in Africa
● Have 2Mbps high speed video links to upload
to Europe
● Pre-planned
● No remote technical people
● Accent is the perfect solution!
● Upload 2x more efficient
● Same OB as before of introducing Accent
● Managed from NOC
First Accent customer
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4. Confidential and proprietary information
Cellular Backhaul
● High throughput BTS sites
enjoy the SCPC Mode
● Low throughput BTS sites or
Node B data traffic enjoy the
bursty Mode (TDMA)
SkyEdge II Hub with
MCRs and MCDs
BSC
or
RNCMSC
LAN
LAN
Abis
Interface
over LAN
A Interface
BTS / NodeB
SkyEdge-II
Accent
VSAT
LAN
SkyEdge-II
Accent
VSAT
New Hub component: MCD
Quad Demodulator for Accent in SCPC Mode
Benefit to the Service Provider:
Better usage of space segment –
The right access scheme in every site
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BTS / NodeB
5. Confidential and proprietary information
Business Continuity
● Service Provider offers to various Enterprises and Governmental
organizations a service of “Business Continuity”
● “Once your main terrestrial connection fails, I will provide you with a high
speed satellite alternative until recovery from the terrestrial problem”
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● Example: Service Provider sells
the protection service to 20
different customers in different
geographical locations
● The offered backup service –2Mbps
● Terrestrial failure – traffic routed to
the on-site VSAT
● VSAT automatically switches to
SCPC (based on VRRP protocol)
● Once terrestrial traffic is restored,
VSAT switches back to TDMA mode INTERNET
Core Network
SkyEdge II Hub
Po
P
SkyEdge II
Accent
Main Backup
IP
6. Confidential and proprietary information 6
PSTN INTERNET/
INTRANET
SkyEdge II
Accent
Residential
Gateway
Video
Conference
User PC User PC
Telephone
LAN
SkyEdge II Hub
PoP
Point of Presence
SkyEdge II
Accent
Traffic through the VSAT tends to be
relatively stable daily during the busy hour
● SCPC Inbound is recommended
● Better usage of space segment
(Point of Presence)
Hundreds of PCs
behind the VSAT
7. Confidential and proprietary information
Unified System – SCPC and TDMA
● Accent – unified MODEM for both SCPC Mode and Burst Mode
● Unified System
● Unified DVB-S2 Outbound for TDMA and SCPC VSATs
● DVB-RCS or DVB-S2 IB
● Same NMS; Same hub; Same VSATs
● All remote VSATs are managed (SCPC or TDMA)
● DVB-S2 ACM inbound, 0.3-10Msps
● Speed to 24Mbps inbound or 24Mbps outbound, total 40Mbps
● On Demand TDMA to SCPC Switchover
● Change from Burst to SCPC (Continuous Carrier) and back to Burst on the fly
● “Classifier” based Triggering – one or more of the classifiers that serve for QoS prioritization
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8. Confidential and proprietary information
Triggering – TDMA to SCPC and Back
● The Classifier analyzes the inbound traffic of the VSAT
● The Destination IP Addresses (one address or a range of addresses)
can serve as the trigger
● Similarly, TCP/UDP ports
● The DSCP code (packets that are already colored)
● VRRP protocol serves to identify failure of a terrestrial primary
connection and automatically switches the VSAT to SCPC Mode
● The VRRP protocol also selects the VSAT as the Master Router, which
means that the traffic is carried through the VSAT as long as the
terrestrial connection is down
● Differentiated services Code Point (DSCP)
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9. Confidential and proprietary information
Applications
WHAT HAPPEN IF WE NEED TO MIX SEVERAL DIFFERENT NEEDS?
● Cellular Backhaul (e.g. GSM; UMTS) w/ continuous bandwidth
● Cellular Backhaul (e.g. 3G/LTE) w/ burst traffic and/or small cells
● ISP Point of Presence (PoP)
● Internet access
● Business Continuity
● SCPC up to 5, 10, 20, 24 Mbps Inbound (instead of only 2 Mbps)
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