Yusuke Aoyama
IPv6style
It is said that Mobile WiMAX is very compatible technically with IPv6; there have also been activities involving industry groups, such as the announcement by the WiMAX Forum and IPv6 Forum that they would collaborate. So, I interviewed Mr. Kazuo Morohashi, CTO, WiMAX Planning Division, eAccess (one of the principal members at the WiMAX Forum), and asked him about Mobile WiMAX field trials as well as IPv6.
Yusuke AoyamaIPv6style
Experiments have been as difficult as expected
When I first saw the Mobile WiMAX testing device, I thought, “It’s bigger than I expected it would be”. Mr. Morohashi laughed and said, “That’s because this is the prototype.
"If you see it from the top, you'll know. The board itself is big in its own way, but there is a fan around here. Since it generates quite a bit of heat, it has quite a large fan."
Mobile WiMAX testing device
Although the testing device is about the same size as a consumer broadband router, when you actually hold it in your hand, it feels surprisingly heavy. This is because a general-purpose aluminum case was used since their priorities were on easy manufacturing and cooling so that they could create it quickly for testing. There is an RJ45 port on the side so that you can run it as a media converter by connecting it to a notebook computer's Ethernet port.
LED for status display
Antenna and input/out ports
It will become smaller when it becomes an actual product and is used for services; he says, "It is possible that it will be put inside of computers or PDAs as a module, or depending on how things go, it could be put into mobile devices."
The outdoor Mobile WiMAX field trials by eAccess started on July 18th; they have been carried out at Toranomon, Shinbashi and Shiba, where the base stations are installed. One base station supports an area with a radius of a little less than 1 km, and the three stations are installed so that the three supported areas overlap to just the right extent.
A base station installed on the rooftop of a thirteen-story building
One of the base stations is installed on the rooftop of a thirteen-story building and three pairs of antennas provide coverage in three directions, providing total 360-degree coverage. The other two base stations are installed in a similar manner.
Three pairs of antennas provide coverage in three directions
for specific reasons. First, it is very convenient, since this area is close to eAccess headquarters. Second, it is an area in Tokyo where office buildings are particularly concentrated.
"In all the world, Tokyo is the city with the most complicated structure. High-rise buildings coexist with short buildings; it's not just high-rise buildings. Moreover, the density of buildings is very high. If we can make full use of this technology in this town, we can probably use it anywhere we go," says Mr. Morohashi.
In a city with such a complicated structure, since the area is flooded with reflections of radio waves as well as electromagnetic noises from unknown sources, it is a difficult environment for wireless services. Especially in areas near the center of the city, there are many radio waves that can cause interference, e.g. cell phones, PHS', Wi-Fi used in offices, etc., which makes this area the best suited for the field trials.
ving three stations. "For example, if there are only two stations, you can test in only one location, but if there are three, you can test in three locations. Also, since we can get various statistical data, three stations are good [for testing]," says Mr. Morohashi.
Testing areas on the map (excerpt from eAccess' press release)
This can be said for any wireless service, but when troubleshooting is already difficult for this type of service since it cannot be seen, the difficulties are increased since it is for mobile. Even if a service uses the same technology and the same radio wave frequency, communication channels could become remarkably unstable when using mobile as opposed to using a wired network. This is because "disturbance factors are increased" just by moving client devices.
They have actually started the field trials and the difficulties are "as we expected", says Mr. Morohashi.
They will perform these field trials, in a series of steps, for about one year. At the current time, they are focusing on the physical layer, mainly measuring the characteristics of the radio waves and performing tests on the Mobile WiMAX system itself. They plan to continue field trials on the physical layer until the end of fiscal year 2006, and then move onto testing the IP layer as well as application layer.
The measuring itself is simple. While they drive around the test area in a car with measuring instruments, they measure the electric field strength and throughput, and log the information along with GPS data. They use an ordinary business van and put an antenna on top of the roof; the loading area is full of measuring instruments.
The data they collected is analyzed by a special tool and then the results are studied by testing members. When some analyzed data cannot be explained, the members continue to study them until they come to a conclusion; in some cases, it takes until 3-4 am.
Also, in the area where eAccess' office is located, road security is tight since the American Embassy is nearby. Because of this, at times they were asked questions by the police when they do things such as parking their car (which is full of measuring instruments) during tests and loading/unloading equipment. So, these days they put a sign on the van that says "performing field trials".
Service Details
eAccess made their commitment towards Mobile WiMAX clear when they founded the WiMAX Planning Division in December 2005. They are moving forward at a fast pace, starting field trials only 8 months after the division's foundation. This was possible because eAccess is one of the principal members of the WiMAX Forum, and at the same time, they contribute to standardization activities due to their technical abilities that allow them to carry out development and testing on their own.
Once they have an idea of how the current round of tests will turn out, they will move on to the next step; according to their plans, they hope to move on to testing higher layers, such as applications and mobile IP, by March 2007. To mobile WiMAX, IP mobility is an essential technology. Because of this reason, testing mobile IP-related technologies is one of the important tasks to carry out within the current field trials.
Also, it is said that Mobile WiMAX is very compatible technically with IPv6. In fact, the WiMAX Forum and the IPv6 Forum entered into a cooperative relationship in July 2006 aiming to resolve technical issues as well as to work together in the area of marketing. So, there are great hopes for a synergy effect in the industry.
Behind this movement, there is the idea that when every mobile devices becomes IP-based, it will then be efficient to embed IP in each device, and when that happens, IPv6 addresses, not IPv4, will be needed due to the address space issue.
Mr. Morohashi, CTO, WiMAX Planning Division, eAccess
However, according to Mr. Morohashi, it is not that simple. First, there is an issue of collecting addresses of idle devices. Even though the IPv6 address space is enormous, is it really okay to dispose of IPv6 addresses that are embedded in the devices that the usage status is unknown?
Another issue is the issue of the dual network cost while transitioning from IPv4 to IPv6. Currently, it is difficult to build an open network only with IPv6. So, dual networks with IPv4 are needed and that costs more than networks that are only IPv4 or IPv6.
As long as these issues are not resolved, embedding an IPv6 address in devices is something that "I can't quite decide if it's good or bad", says Mr. Morohashi. Although they cannot come to a conclusion right now, things will probably be clear when they start seeing the direction of the services through continued field trials and the increased debates among users and service providers.
Then, when will Mobile WiMAX services actually start and what will they be like?
It is said that Mobile WiMAX services will start around 2008-2009. Ideas about actual services will probably undergo changes based on what kind of services users want and what kind of services companies want to provide.
However, it is very possible that the first service will be a data communication service for mobile PCs. One clue can be seen in an action by Intel, the leading manufacturer of CPU/chips for computers.
Intel announced that they are going to integrate WiMAX features into mobile chip sets and they are already showing samples at developer events and such. For Wi-Fi, they have already established the Centrino brand, a combination of CPU + chip set + Wi-Fi module, and they would like to do the same with WiMAX.
Most of the notebook computers currently sold have Wi-Fi installed. Although it is up to the user whether he/she uses it or not, it is a fact that it has gradually come to be seen by users as a default feature in notebook computers. Intel aims to do the same for WiMAX; they want it so that when a user purchases some sort of a client device, the WiMAX feature is already installed.
Furthermore, Intel's action is in concert with other companies who aim to enter the Mobile WiMAX service industry. Mr. Morohashi says, "There are some ideas that Intel is talking about that I feel are quite close to our own thinking. Although [the WiMAX module] is included without the customer asking for it, it is up to them whether they will use it or not."
The problem is that there are many issues related to regulations as well as business issues. Mr. Morohashi also says, "We are only throwing out ideas for now," and emphasizes that they are only talking about ideals.
However, it is certain that Mobile WiMAX is currently the closest method to achieve our ideal, a society where we can connect anything to networks anywhere at any time. In addition, although various technologies have been suggested in order to achieve that goal, how much we can use those technologies depends on the future testing and development.
"After all, since I am also in a position where I have to lead others in terms of technological innovation, I don't intend to say things negatively. I would like to take things positively as much as possible and I do have a fundamental stand that we should put effective technologies in use as early as possible," says Mr. Morohashi.
Even if it is technically possible to implement it, that does not mean it is always the best solution since you cannot ignore the cost issues as well as compliance issues if you aim to commercialize it.
"Since there is no use in continuing to talk about desktop theories, I think we need to adopt down-to-earth technologies. Using the testbed for those technologies, we would like to test as much as possible to see how stable they are," says Mr. Morohashi.
eAccess
http://www.eaccess.net/en/index.html
Press Release: eAccess to commence the Mobile WiMAX field trial
http://www.eaccess.net/cgi-bin/e_press.cgi?id=354
