4G Technologies - Article from Sun's Website on Mobile IP

4G Topics of Interest - From the Net

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January 8, 2002 -- Engineers at Sun Microsystems Laboratories are building wireless technologies that promise to integrate voice and web data in an IP-based mobile communications system known as the Fourth Generation (4G) wireless network. They are also bringing their expertise to standards bodies to make sure that 4G protocols are based on open system solutions. The challenges are considerable, but so is the payoff. It's the difference between truly mobile, versus merely portable, computing.

Jackson Wong leads a team of engineers who are designing and implementing mobile IP-based tools and protocols. They are literally helping to set the standard in secure, versatile, and responsive wireless communication technologies. Some of the tools are bundled in the Solaris[tm] 8 Operating Environment. Others are in advanced development. The tools and protocols anticipate an integrated wireless communications core layer based on open systems solutions also known as "4G" -- the Fourth Generation IP-based wireless network. According to Wong, Sun Labs engineers "are playing a leading role" on the standards bodies that will define the 4G universe.

Building a Better Tunnel

Sun Microsystems Laboratories engineers James Kempf and Jonathan Wood design tunnels, but not the kind that require hard hats to build. Kempf's and Wood's tunnels burrow through the air. You can't see or touch them, but they are substantial enough to make all the difference in the world if you happen to be roaming with a cell phone or wireless Internet device.

As we commute, stroll, and otherwise move about, our mobile phone calls and wirelss device connections get handed off from cell to cell and from network to network. Kempf's and Wood's tunnels could make possible uninterrupted, mobile cell phone conversations and Internet data access.

Glitch-free cell phone calls and instant mobile web access loom large as demands of consumers and the workplace. Mobile consumers want responsive and reliable cell calls, email paging, and web access. It's the difference between truly mobile, as opposed to merely portable, computing, and it's a difference that's been underscored since the September 11 attacks on lower Manhattan that left tens of thousands of workers officeless. (see "Mobile or Portable?" sidebar)

Unfortunately, a maze of outdated and competing standards, proprietary technologies, and related technical problems is holding back an otherwise promising mobile communications future. Connection hiccups, echo chamber effects, and dropped calls are so common -- and so frustrating -- that they actually discourage use. Studies suggest that any delay may stop a mobile web user from even trying to access the net. Research also suggests that users with reliable, instant access use the Internet as much as three times more than those who must dial in for each access.

Help is on the way. The work that Kempf and Wood are doing is part of the Mobile IP (Internet Protocol) initiative. Mobile IP refers to a group of protocols and implementations that keep cell phones and mobile Internet devices functioning smoothly as users physically travel through different network topologies. Mobile IP, together with SCTP, SLP, Diameter, and IP RAN describe protocols and technologies that Kempf, Wood, Dave Frascone, their colleagues, and team leader Jackson Wong are pioneering in behalf of a quest: the fourth-generation IP-based wireless communications network.

According to Kempf, 4G is all about an integrated, global network that's based on an open systems approach. The goal of 4G is to "replace the current proliferation of core cellular networks with a single worldwide cellular core network standard based on IP for control, video, packet data, and VoIP," says Kempf. And this, he told an audience at the University of California, Berkeley, would "provide uniform video, voice, and data services to the cellular handset or handheld Internet appliance, based entirely on IP." The advantages are as considerable as the challenges.

On Deck: 3G or 4G?

The current and previous generations of wireless communications present an alphabet soup of acronyms, standards, and technologies with a sprinkling of digital-analog amalgams thrown in for good measure. These ingredients, as it turns out, reflect the very problems that an all IP-based core layer might solve.

We are well beyond 1G, which supported the first generation of analog cell phones. Vestiges of 1G survive, though. They include a signaling protocol known as SS7 (Signaling System 7). SS7, "a crusty signaling technology developed by Ma Bell in the 1960s," according to Kempf, has only recently become obsolete and remains in wide use.

At the moment, wireless network technologies are somewhere between 2G and 2.5G. The second generation of mobile communications technology was all about digital PCS. The problem, however, is that much of the digital network was implemented for, or overlaid onto, proprietary networking equipment.

Taken together, the 2G/2.5G technologies are far from seamless. They range from spread-spectrum CDMA (Code-Division Multiple Access) in North America to narrow spectrum TDMA (Time Division Multiple Access) and GSM (Global System for Mobile Communications), the de facto standards in Europe and Asia. In addition to these incompatibilities, both systems feature relatively slow-speed digital voice with very little bandwidth left over for data.

Expectations for 3G, an ITU specification, run high. They include increased bandwidth: up to 384 Kbps when a device is moving at pedestrian speed, 128 Kbps in a car, and 2 Mbps in fixed applications. In theory, 3G would work over North American as well as European and Asian wireless air interfaces. A new air interface, EDGE (Enhanced Data GSM Environment), has been developed specifically to meet the bandwidth needs of 3G. (EDGE is a faster version of GSM wireless service.)

In fact, the outlook for 3G is neither clear nor certain. Part of the problem is that network providers in Europe and North America currently maintain separate standards bodies (3GPP for Europe and Asia; 3GPP2 for North America). The standards bodies mirror differences in air interface technologies.

In addition to 3G's technical challenges there are financial questions. Not the least of these is the expense of building out systems based on less-than-compatible 2G technologies.

These technological and financial issues cast a shadow over 3G's desirability. "There is some concern that 3G will never happen," says Kempf. That concern is grounded, in part, in the growing attraction of 4G wireless technologies.

IP in the Sky

An all IP-based 4G wireless network has intrinsic advantages over its predecessors. For starters, IP is compatible with, and independent of, the actual radio access technology. "With IP, you basically get rid of the lock-in between the core networking protocol and the link layer, the radio protocol," says Kempf.

"IP tolerates a variety of radio protocols. It lets you design a core network that gives you complete flexibility as to what the access network is," observes Kempf. "You could be a core network provider that supports many different access technologies, 802.11, WCDMA, Bluetooth, HyperLAN, and some that we haven't even invented yet, such as some new CDMA protocols." An all IP network's technology tolerance means unimpeded innovation all around. "The core [IP] network can evolve independently from the access network. That's the key for using all IP," says Kempf.

A 4G IP wireless network enjoys a financial adantage over 3G as well. According to Kempf, 4G "equipment costs are four to ten times cheaper than equivalent circuit-switched equipment for 2G and 3G wireless infrastructure." An open systems IP wireless environment would probably further reduce costs for service providers by ushering in an era of real equipment interoperability. Wireless service providers would no longer be bound by single-system vendors of proprietary equipment.

An IP wireless network would replace the old SS7 (Signaling System 7) telecommunications protocol, a task that many believe to be long overdue. "The SS7 network is massively redundent," says Kempf. That's because SS7 signal transmission uses a heartbeat that consumes a large part of the network bandwidth even when there is no signaling traffic. IP networks use other less bandwidth-expensive mechanisms to achieve reliability.

Last but not least, an all-IP wireless core network would enable services that are sufficiently varied for consumers. That means improved data access for mobile Internet devices. Today, wireless communications are heavily biased toward voice, even though studies indicate that growth in wireless data traffic is rising exponentially relative to demand for voice traffic. (In response, the 802.11 data transfer protocol, a wireless LAN standard developed by IEEE, has attracted much interest as a distinct data access technology that can work on a variety radio of spectrums, including infrared.) Because an all IP core layer is easily scalable, it is ideally suited to meet this challenge. "The goal," says Kempf, "is a merged data/voice/multimedia network."

The inherent advantages of 4G have some people thinking that we may leapfrog from 2.5G to 4G. As team leader Jackson Wong puts it, "we are not working on the next (3G) generation of telco communications, but two generations out." This, says Wong, means proceeding on two fronts: working the standards organizations to advance international acceptance of 4G protocols, and developing technology to support IP wireless solutions.

At Sun Microsystems, work is proceeding on a variety of 4G technologies and protocols. More>>