Table of Contents
1. Introduction
2. 3G Wireless Market Drivers
3. Existing Mobile Networks
4. Next Generation Mobile Networks
5. Evolution to 3G Wireless Technology
6. Comparison of 2G and 3G Mobile Networks
7. Trillium's Wireless Software Solution
8. About Trillium
1. Introduction
Third Generation (3G) mobile devices and services will transform wireless communications into
on-line, real-time connectivity. 3G wireless technology will allow an individual to have immediate
access to location-specific services that offer information on demand. The first generation of
mobile phones consisted of the analog models that emerged in the early 1980s. The second
generation of digital mobile phones appeared about ten years later along with the first digital
mobile networks. During the second generation, the mobile telecommunications industry
experienced exponential growth both in terms of subscribers as well as new types of value-added
services. Mobile phones are rapidly becoming the preferred means of personal communication,
creating the world's largest consumer electronics industry.
The rapid and efficient deployment of new wireless data and Internet services has emerged as a
critical priority for communications equipment manufacturers. Network components that enable
wireless data services are fundamental to the next-generation network infrastructure. Wireless
data services are expected to see the same explosive growth in demand that Internet services
and wireless voice services have seen in recent years.
This white paper presents an overview of current technology trends in the wireless technology
market, a historical overview of the evolving wireless technologies and an examination of how the
communications industry plans to implement 3G wireless technology standards to address the
growing demand for wireless multimedia services. Finally, this paper presents Trillium?s solutions
which enable wireless communications and Internet infrastructure equipment manufacturers to
develop 3G network elements for quick and efficient deployment.
2. 3G Wireless Market Drivers
Telecommunications service providers and network operators are embracing the recently
adopted global third generation (3G) wireless standards in order to address emerging user
demands and to provide new services. The concept of 3G wireless technology represents a shift
from voice-centric services to multimedia-oriented (voice, data, video, fax) services. In addition,
heavy demand for remote access to personalized data is fueling development of applications,
such as the Wireless Application Protocol (WAP) and multimedia management, to complement
the 3G protocols. Complementary standards, such as Bluetooth, will enable interoperability
between a mobile terminal (phone, PDA etc.) and other electronic devices, such as a
laptop/desktop and peripherals, providing added convenience to the consumer and allowing for
the synchronization and uploading of information at all times.
According to Lehman Brothers, approximately 50 percent of current voice services subscribers
are expected to use wireless data services by 2007, instead of 25 percent as previously forecast
1
.
Lehman Brothers further predicts that, within seven years, 18 percent of cellular revenues and 21
percent of PCS (personal communications services) revenue will come from wireless data
services. Cellular subscriptions are forecast to exceed one billion by 2003
2
, compared with the
306 million that was forecast at the end of 1998, representing a compound annual growth of 29
percent. Demand for voice services has traditionally been a market driver. However, today,
demand for data services has emerged as an equally significant market driver. After many years
of stasis, the telecommunications industry is undergoing revolutionary changes due to the impact
of increased demand for data services on wireline and wireless networks. Up until recently, data
traffic over mobile networks remained low at around 2% due to the bandwidth limitations of the
present second-generation (2G) wireless networks. Today, new technologies are quickly
emerging that will optimize the transport of data services and offer higher bandwidth in a mobile
environment. As a case in point, the increased use of the Internet as an acceptable source for
information distribution and retrieval, in conjunction with the increased demand for global mobility
has created a need for 3G wireless communications protocols.
The third generation of mobile communications will greatly enhance the implementation of
sophisticated wireless applications. Users will be able to utilize personal, location-based wireless
information and interactive services. Also, many companies and corporations are restructuring
their business processes to be able to fully exploit the opportunities provided by the emerging
new wireless data services. Many advanced wireless services are already available today, and
the introduction of 3G wireless technologies will add to their ubiquity.
3. Existing Mobile Networks
3.1 First Generation Wireless Technology
The first generation of wireless mobile communications was based on analog signalling. Analog
systems, implemented in North America, were known as Analog Mobile Phone Systems (AMPS),
while systems implemented in Europe and the rest of the world were typically identified as a
variation of Total Access Communication Systems (TACS). Analog systems were primarily based
on circuit-switched technology and designed for voice, not data.
3.2 Second Generation Wireless Technology
The second generation (2G) of the wireless mobile network was based on low-band digital data
signalling. The most popular 2G wireless technology is known as Global Systems for Mobile
Communications (GSM). GSM systems, first implemented in 1991, are now operating in about
140 countries and territories around the world. An estimated 248 million users now operate over
GSM systems. GSM technology is a combination of Frequency Division Multiple Access (FDMA)
and Time Division Multiple Access (TDMA). The first GSM systems used a 25MHz frequency
spectrum in the 900MHz band. FDMA is used to divide the available 25MHz of bandwidth into
124 carrier frequencies of 200kHz each. Each frequency is then divided using a TDMA scheme
into eight timeslots. The use of separate timeslots for transmission and reception simplifies the
electronics in the mobile units. Today, GSM systems operate in the 900MHz and 1.8 GHz bands
throughout the world with the exception of the Americas where they operate in the 1.9 GHz band.
In addition to GSM, a similar technology, called Personal Digital Communications (PDC), using
TDMA-based technology, emerged in Japan. Since then, several other TDMA-based systems
have been deployed worldwide and serve an estimated 89 million people worldwide. While GSM
technology was developed in Europe, Code Division Multiple Access (CDMA) technology was
developed in North America. CDMA uses spread spectrum technology to break up speech into
small, digitized segments and encodes them to identify each call. CDMA systems have been
implemented worldwide in about 30 countries and serve an estimated 44 million subscribers.
While GSM and other TDMA-based systems have become the dominant 2G wireless
technologies, CDMA technology is recognized as providing clearer voice quality with less
background noise, fewer dropped calls, enhanced security, greater reliability and greater network
capacity. The Second Generation (2G) wireless networks mentioned above are also mostly
based on circuit-switched technology. 2G wireless networks are digital and expand the range of
applications to more advanced voice services, such as Called Line Identification. 2G wireless
technology can handle some data capabilities such as fax and short message service at the data
rate of up to 9.6 kbps, but it is not suitable for web browsing and multimedia applications.
4. Next Generation Mobile Networks
4.1 Second Generation (2G+) Wireless Networks
As stated in a previous section, the virtual explosion of Internet usage has had a tremendous
impact on the demand for advanced wireless data communication services. However, the
effective data rate of 2G circuit-switched wireless systems is relatively slow -- too slow for today's
Internet. As a result, GSM, PDC and other TDMA-based mobile system providers and carriers
have developed 2G+ technology that is packet-based and increases the data communication
speeds to as high as 384kbps. These 2G+ systems are based on the following technologies: High
Speed Circuit-Switched Data (HSCSD), General Packet Radio Service (GPRS) and Enhanced
Data Rates for Global Evolution (EDGE) technologies.
HSCSD is one step towards 3G wideband mobile data networks. This circuit-switched technology
improves the data rates up to 57.6kbps by introducing 14.4 kbps data coding and by aggregating
4 radio channels timeslots of 14.4 kbps.
GPRS is an intermediate step that is designed to allow the GSM world to implement a full range
of Internet services without waiting for the deployment of full-scale 3G wireless systems. GPRS
technology is packet-based and designed to work in parallel with the 2G GSM, PDC and TDMA
systems that are used for voice communications and for table look-up to obtain GPRS user
profiles in the Location Register databases. GPRS uses a multiple of the 1 to 8 radio channel
timeslots in the 200kHz-frequency band allocated for a carrier frequency to enable data speeds of
up to 115kbps. The data is packetized and transported over Public Land Mobile Networks
(PLMN) using an IP backbone so that mobile users can access services on the Internet, such as
SMTP/POP-based e-mail, ftp and HTTP-based Web services. For more information on GPRS,
please see Trillium's General Packet Radio Service (GPRS) White Paper at
http://trilliumwhats-new/wp_gprs.html
EDGE technology is a standard that has been specified to enhance the throughput per timeslot
for both HSCSD and GPRS. The enhancement of HSCSD is called ECSD, whereas the
enhancement of GPRS is called EGPRS. In ECSD, the maximum data rate will not increase from
64 kbps due to the restrictions in the A interface, but the data rate per timeslot will triple. Similarly,
in EGPRS, the data rate per timeslot will triple and the peak throughput, including all eight
timeslots in the radio interface, will exceed 384 kbps.
The following is a brief description of each protocol layer in the GPRS network infrastructure:
? Sub-Network Dependent Convergence Protocol (SNDCP): protocol that maps a network-level
protocol, such as IP or X.25, to the underlying logical page link control. SNDCP also provides
other functions such as compression, segmentation and multiplexing of network-layer
messages to a single virtual connection.
? Logical Link Control (LLC): a data page link layer protocol for GPRS which functions similar to
Link Access Protocol ? D (LAPD). This layer assures the reliable transfer of user data across
a wireless network.
? Base Station System GPRS Protocol (BSSGP): processes routing and quality of service
(QoS) information for the BSS. BSSGP uses the Frame Relay Q.922 core protocol as its
transport mechanism.
? GPRS Tunnel Protocol (GTP): protocol that tunnels the protocol data units through the IP
backbone by adding routing information. GTP operates on top of TCP/UDP over IP.
? GPRS Mobility Management (GMM/SM): protocol that operates in the signalling plane of
GPRS, handles mobility issues such as roaming, authentication, selection of encryption
algorithms and maintains PDP context.
? Network Service: protocol that manages the convergence sub-layer that operates between
BSSGP and the Frame Relay Q.922 Core by mapping BSSGP's service requests to the
appropriate Frame Relay services.
? BSSAP+: protocol that enables paging for voice connections from MSC via SGSN, thus
optimizing paging for mobile subscribers. BSSAP+ is also responsible for location and routing
updates as well as mobile station alerting.
??SCCP, MTP3, MTP2 are protocols used to support Mobile Application Part (MAP) and
BSSAP+ in circuit switched PLMNs.
? Mobile Application Part (MAP): supports signaling between SGSN/GGSN and
HLR/AuC/EIR.
4.2 Third Generation (3G) Wireless Networks
3G wireless technology represents the convergence of various 2G wireless telecommunications
systems into a single global system that includes both terrestrial and satellite components. One of
the most important aspects of 3G wireless technology is its ability to unify existing cellular
standards, such as CDMA, GSM, and TDMA, under one umbrella. The following three air
interface modes accomplish this result: wideband CDMA, CDMA2000 and the Universal Wireless
Communication (UWC-136) interfaces.
Wideband CDMA (W-CDMA) is compatible with the current 2G GSM networks prevalent in
Europe and parts of Asia. W-CDMA will require bandwidth of between 5Mhz and 10 Mhz, making
it a suitable platform for higher capacity applications. It can be overlaid onto existing GSM, TDMA
(IS-36) and IS95 networks. Subscribers are likely to access 3G wireless services initially via dual
band terminal devices. W-CDMA networks will be used for high-capacity applications and 2G
digital wireless systems will be used for voice calls.
The second radio interface is CDMA2000 which is backward compatible with the second
generation CDMA IS-95 standard predominantly used in US. The third radio interface, Universal
Wireless Communications ? UWC-136, also called IS-136HS, was proposed by the TIA and
designed to comply with ANSI-136, the North American TDMA standard.
3G wireless networks consist of a Radio Access Network (RAN) and a core network. The core
network consists of a packet-switched domain, which includes 3G SGSNs and GGSNs, which
provide the same functionality that they provide in a GPRS system, and a circuit-switched
domain, which includes 3G MSC for switching of voice calls. Charging for services and access is
done through the Charging Gateway Function (CGF), which is also part of the core network. RAN
functionality is independent from the core network functionality. The access network provides a
core network technology independent access for mobile terminals to different types of core
networks and network services. Either core network domain can access any appropriate RAN
service; e.g. it should be possible to access a ?speech? radio access bearer from the packet-switched
domain.
3G wireless technology introduces new Radio Access Network (RAN) consisting of Node B and
RNC network elements. The 3G Core Network consists of the same entities as GSM and GPRS:
3G MSC/VLR, GMSC, HLR/AuC/EIR, 3G-SGSN, and GGSN. IP technology is used end-to-end
for multimedia applications and ATM technology is used to provide reliable transport with QoS.
3G wireless solutions allow for the possibility of having an integrated network for circuit-switched
and packet-switched services by utilizing ATM technology. The BSC may evolve into an RNC by
using add-on cards or additional hardware that is co-located. The carrier frequency (5Mhz) and
the bands (2.5 to 5Ghz) are different for 3G wireless technology compared to 2G/2G+ wireless
technology. Evolution of BSC to RNC requires support for new protocols such as PDCP, RRC,
RANAP, RNSAP and NBAP. Therefore, BTS' evolution into Node B may prove to be difficult and
may represent significant capital expenditure on the part of network operators.
MSC evolution depends on the selection of a fixed network to carry the requested services. If an
ATM network is chosen, then ATM protocols will have to be supported in 3G MSC along with
interworking between ATM and existing PSTN/ISDN networks.
The evolution of SGSN and GGSN to 3G nodes is relatively easier. Enhancements to GTP
protocol and support for new RANAP protocol are necessary to support 3G wireless systems.
ATM protocols need to be incorporated to transport the services. The HLR databases evolve into
3G-HLR by adding 3G wireless user profiles. The VLR database must also be updated
accordingly. The EIR database needs to change to accommodate new equipment that will be
deployed for 3G wireless systems. Finally, global roaming requires compatibility to existing
deployment and graceful fallback to an available level when requested services are not available
in the region. Towards this end, the Operator Harmonization Group (OHG) is working closely with
3G Partnership Projects (3GPP and 3GPP2) to come up with global standards for 3G wireless
protocols.
8. About Trillium
Trillium Digital Systems is the leading provider of communications software solutions for the
converged network infrastructure. Trillium's source code solutions are used in more than 500
projects by industry-leading suppliers of wireless, Internet, broadband and telephony products.
Trillium's high-performance, high-availability software and services reduce the time, risk and cost
of implementing SS7, IP, H.323, MGCP, ATM, Wireless and other standards-based
communications protocols.
Trillium actively participates in the development of 3rd generation systems by developing
standards-based wireless communications protocols. It is likely that the first 3G mobile terminals
will be multi-mode devices, which means that they will support a number of 2nd generation
protocol standards in order to reach wide network coverage and to provide 3rd generation
advanced services. Trillium has extensive know-how in all the major communications protocol
standards in the world and can provide solutions for many types of networks.
Trillium designs all its portable software products using the Trillium Advanced Portability
Architecture (TAPA?), a set of architectural and coding standards that ensure the software is
completely independent of the compiler, processor, operating system and architecture of the
target system. This makes Trillium products portable, consistent, reliable, high quality, high
performance, flexible, and scaleable. This architecture also ensures that all Trillium protocols can
interwork seamlessly in the same or between different networks.
As mentioned above, successful implementation, adoption, and overall acceptance of the 3G
wireless networks depends largely on the ability of these new mobile networks to interface and
interwork with the existing 2G and legacy networks currently deployed worldwide. Trillium offers a
broad range of protocols for first- and second-generation mobile networks, legacy networks, and
fixed networks. Trillium's products allow wireless communications equipment manufacturers to
develop "best-in-class" next-generation mobile networks, to ensure success of the network
operator and service provider, and to ensure wide acceptance of the new services by end-users.
Additional information is available at http://trillium.com.
