Skip EDGE in Favor of W-CDMA?
While EV-DO will be the 3G flagpole for CDMA operators, for GSM operators it makes more sense to move on to GPRS, and then to EDGE, mainly to protect their existing investments. TDMA operators can also choose to overlay their networks with GSM technology and then do a GPRS upgrade. The next stage can be EDGE. In the US, TDMA operators like AT&T and Cingular have opted for EDGE. On the other hand, European carriers are not too keen on taking this route and many of them are expected to skip EDGE, and move directly to wideband-CDMA (W-CDMA), which is considered a full 3G network technology.

The benefits of migrating to EDGE rather than skipping it in favor of W-CDMA are as follows:

Better Return on Investment: With EDGE, operators can think of having satisfactory returns on their investments in the short to medium term. Similar returns are not likely with W-CDMA deployments. W-CDMA is like installing a totally new network, whereas EDGE is considered merely an upgrade. Also, there is lack of a successful W-CDMA model.

Spectrum Availability: Rolling out W-CDMA requires quite a bit of additional spectrum, and carriers might not have access to that much of spectrum soon.

Optimum Speed: It allows data rates of up to 384 kbps, which can effectively take care of the application needs of today.

This is lower than W-CDMA, which can offer data rates of 2 Mbps. However, it is much better than the 115 kbps of GPRS.

More Applications Likely: Most of the wireless applications will run in the tens-of-kbps range in the near future and not in the Mbps range. So there is more reason to move on to EDGE instead of W-CDMA. In fact, service providers will find it hard to market applications that can utilize the capacity.

1xEV-DO—Competitive Advantage for Operators
1xEV-DO offers high-speed, high-capacity wireless Internet connectivity, and is well suited for bursty data applications. The technology has been optimized for packet data services, leveraging the existing suite of Internet protocols (IP).

A peak data rate of 2.4 Mbps is possible with 1xEV-DO, within a 1.25 MHz CDMA carrier. Support is available for all popular operating systems and software applications. 1xEV-DO offers an always-on user experience.

1xEV-DO’s technological superiority comes, among other things, also from the fact that it places packet data and voice on separate 1.25 MHz channels. This significantly simplifies load-balancing and eases system operation and maintenance.

Operators can reap a host of economic benefits, given the following key competitive advantages possible with a 1xEV-DO system:

Efficient Spectrum Utilization: An aggregate peak capacity of 7.4 Mbps in a 3-cell sector is possible with a 1.25 MHz frequency carrier. This high capacity results in economical use of an operator’s spectrum resources.

Separate Voice, Data Channels: Voice and packet data services are provided on different frequency carriers. This allows the operator to maintain high voice quality and at the same time ensure peak data rates up to 2.4 Mbps.

Increased Revenue Opportunity: The higher capacity of the 1xEV-DO system makes it possible to accommodate a large number of users, without any trade-off in network efficiency. And more users yield more revenues for the operator.

Low Cost per Bit: 1xEV-DO has higher capacity while essentially using the same amount of network resources. Consequently, it delivers the lowest cost per bit for packet data.

Investment Protection: 1xEV-DO can be highly integrated into existing CDMA2000 and cdmaOne base stations, and can use the same PDSN, BSC, cell sites, towers, antennas, and network plans. This can help operators save and leverage existing capital investments.

1xEV-DO ASICs have been in production since September 2001, and devices and networks have been designed and manufactured based on these commercial ASICs. A wide range of support from device and system manufacturers has made 1xEV-DO a low-risk technology, and operators can have a time-to-market advantage too. 1xEV-DO is commercially available in Korea today.

GAIT—Fusion of Two Networks
GSM ANSI Interoperability Team (GAIT) is a network standard that enables seamless roaming between TDMA and GSM networks. GAIT is a new network standard that fuses TDMA and GSM technologies. The goal is to enhance roaming, preserve TDMA customers and serve as an interlude to more advanced networks. The development of GAIT technical specifications began in 1999 by the Universal Wireless Communications Consortium (UWCC) and GSM North America Alliance. These specifications formed the core component of the GSM Global Roaming Forum (GGRF), a global organization dedicated to creating global wireless interoperability.

Interoperability: GAIT terminals and infrastructure enable network compatibility for TDMA operators by overlaying their networks with GSM/GPRS. GAIT terminals will operate on either TDMA or GSM networks, providing service for TDMA customers visiting GSM-dominated geographic areas. GAIT terminals will also service GSM customers visiting TDMA-dominated geographies.

High Data Rates, Toll-quality Voice: Operators that have selected a GSM overlay for their TDMA network will be able to serve their customers in a two-pronged manner. One, the customers will have the benefit of accessing data services provided by a GSM/GPRS network. Two, they will also gain in terms of a more comprehensive digital voice coverage offered by nearly ubiquitous TDMA networks.

Free Space Optics
Free Space Optics (FSO), also called Free Space Photonics (FSP), refers to the transmission of modulated visible or infrared (IR) beams through the atmosphere to obtain broadband communications. Laser beams are generally used, although non-lasing sources, such as light-emitting diodes (LEDs) or IR-emitting diodes (IREDs), will serve the purpose. The theory of FSO is essentially the same as that for fiber-optic transmission. The difference is that the energy beam is collimated and sent through the clear air or space from the source to the destination rather than guided through an optical fiber. If the energy source does not produce a sufficiently parallel beam to travel the required distance, collimation can be done with lenses. At the source, the visible or IR energy is modulated with the data to be transmitted. At the destination, the beam is intercepted by a photodetector, the data is extracted from the visible or IR beam (demodulated), and the resulting signal is amplified and sent to the hardware.

H.323
A standard approved by the International Telecommunication Union (ITU) that defines how audiovisual conferencing data is transmitted across networks. In theory, H.323 should enable users to participate in the same conference even though they are using different video-conferencing applications. Although most video-conferencing vendors have announced that their products will conform to H.323, it is too early to say whether such adherence will actually result in interoperability.

HiperLAN
HiperLAN is a set of wireless local area network (WLAN) communication standards primarily used in the European countries. There are two specifications: HiperLAN/1 and HiperLAN/2. Both have been adopted by the European Telecommunications Standards Institute (ETSI). The HiperLAN standards provide features and capabilities similar to those of the IEEE 802.11 WLAN standards, used in the US and other adopting countries. HiperLAN/1 provides communications at up to 20 Mbps in the 5-GHz range of the radio frequency (RF) spectrum. HiperLAN/2 operates at up to 54 Mbps in the same RF band. HiperLAN/2 is compatible with 3G (third-generation) WLAN systems for sending and receiving data, images, and voice communications. HiperLAN/2 has the potential, and is intended, for implementation worldwide in conjunction with similar systems in the 5-GHz RF band.

Local Multipoint Distribution Services
Local Multipoint Distribution Services (LMDS) is a fixed wireless technology that operates in the 28 GHz band and offers line-of-sight coverage over distances up to 3-5 km. It can deliver data and telephony services to 80,000 customers from a single node. LMDS is one solution for bringing high-bandwidth services to homes and offices within the ‘last mile’ of connectivity, an area where cable or optical fiber may not be convenient or economical. Data transfer rates for LMDS can reach from 1.5 Gbps to 2 Gbps, but a more realistic value may average around 38 Mbps (downstream).

MPLS
Multiprotocol Label Switching (MPLS) is a standards-approved technology for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multiprotocol because it works with the IP, asynchronous transport mode (ATM), and frame relay network protocols. With reference to the standard model for a network (the Open Systems Interconnection, or OSI model), MPLS allows most packets to be forwarded at the layer 2 (switching) level rather than at the layer 3 (routing) level. In addition to moving traffic faster overall, MPLS makes it easy to manage a network for quality-of-service (QoS). For these reasons, the technique is expected to be readily adopted as networks begin to carry more and different mixtures of traffic.

Telemetrics
Telemetrics is a technology that involves the automatic measurement and transmission of data from remote sources. The process of measuring data at the source and transmitting it automatically is called telemetry. The two terms, telemetry and telemetrics, are often used interchangeably. In general, telemetrics works in the following way: sensors at the source measure either electrical data (such as voltage or current) or physical data (such as temperature or pressure). These are converted to specific electrical voltages. A multiplexer combines the voltages, along with timing data, into a single data stream for transmission to the distant receiver. Upon reception, the data stream is separated into its original components and the data is displayed and processed according to user specifications.

VLAN
A virtual (or logical) LAN (VLAN) is a local area network with a definition that maps workstations on some other basis than geographic location (for example, by department, type of user, or primary application). The virtual LAN controller can change or add workstations and manage load-balancing and bandwidth-allocation more easily than with a physical picture of the LAN. Network management software keeps track of relating the virtual picture of the LAN with the actual physical picture.

W-CDMA
Wideband Code Division Multiple Access (W-CDMA) is a CDMA channel that is four times wider than the current channels that are typically used in 2G networks in North America. In January 1998, European Telecommunications Standards Institute (ETSI) decided to choose the W-CDMA technology to be the multiple access techniques for the third-generation mobile telephone system. For a mobile communication system, a key parameter is the system capacity. A number of methods to increase system capacity in a W-CDMA network are discussed.