Satellite Systems in B3G Wireless

 
Satellite Systems in B3G Wireless
There was a notion that satellites are an expensive way to deliver services and cannot compete in
terms of QoS with terrestrial service providers. The satellite and terrestrial communities are changing
their minds about competing with one another, and in B3G systems they will strive to collaborate,
cooperate, and find ways to integrate their devices into the ubiquitous net.
In satellite communications, a division is made between Fixed satellite service (FSS), Broadcast
satellite service (BSS) and Mobile satellite service (MSS) delivery. In FSS, satellites operate mainly
in a point-to-point mode as part of the core network and provide high-capacity links in telecommunications
and ISPs. On a point-to-point basis, IPv6 operations pose no problems and are currently
in operation over many satellite links. Within the FSS/BSS domain, satellites are used extensively
to deliver video services to cable heads or direct to home (DTH). Most of these services have now
been transferred to MPEG-DVB-S packetized transmission. Interactive television is available in this
digitized service through low rate channels with proprietary protocols via, mostly at the moment,
landline. The DVB-S standard is becoming an industry standard for the delivery of IP via satellite,
although it was not primarily designed for this purpose and is not optimal.
For the mobile domains, the success has been with delivery to a niche market to ships, planes,
and land vehicles. The service is now digital and packet based, using again a proprietary protocol, and
with the introduction of the latest satellites will be capable of delivering 3G-like services (however, it
is still TDMA). The Regional GEO system Thuraya seems to be taking off well with a good customer
basis and has wide coverage over Asia and Europe, providing 2G+ services in areas not well served
by terrestrial infrastructure. All of these systems are capable of extensions to 3G-like services and
are especially suited to those services in which location data and communications together are key.
So far mobile satellites have either selected niche areas or tried to compete in the mass market
with cellular services. In the long run, such competition will not be fruitful, but collaboration with
cellular services in the access networks will be beneficial. This is true mainly in two areas. The first
is in the coverage of remote areas that would be too expensive to be served by cellular services.
Providing such services would be more expensive but could form a value-added offering for mobile
service providers. An adjunct to this would be the provision of disaster services to back up cellular
services. The second, and perhaps more interesting, is the delivery of multimedia broadcast and
multicast service (MBMS) services to the mass market. Within 3G networks and also beyond, these
services are very difficult and expensive to be delivered in a cellular format. However, they are
ideally matched to the attributes of a satellite network in terms of the broadcast coverage and thus
we have a win–win situation. The delivery of multimedia content in MBMS to a large customer
base via satellite can reduce the cost by orders of magnitude over cellular networks. Moreover, with
sufficient large storage capacity in the user terminals, unidirectional point-to-multipoint services are
able to provide on-demand and interactive applications because push and store mechanisms make the
point-to-multipoint relationship transparent to users.
In a truly integrated satellite/cellular system to be used by mobile operators, satellites will be
complemented by terrestrial repeaters known as intermediate module repeaters (IMRs) to provide
cost-effective services. This collaboration is what is envisioned in a B3G environment [549].