Home > Articles > Networking > Wireless/High Speed/Optical

📄 Contents

  1. Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley
  2. Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley, Continued
Like this article? We recommend

Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley, Continued

Question: Interesting stuff! Now, could you tell us some about the companies you've started that resulted from MPRG research?

In 1989, I started a company with a couple of great students, and we called it TSR Technologies, Inc. It was a cellular radio/PCS manufacturing firm, and in 1993 we sold it to Allen Telecom and it became Grayson Wireless, which is now a big test equipment maker.

Wireless Valley was a spinoff I did a couple of years ago with a PhD student, Roger Skidmore, who's now running it. It's pretty exciting because it's leading the way for in-building wireless measurement, deployment, and network management. We'd invented some new technology and had some new concepts that we thought could really be of value to the industry. So it's kind of a push technology, whereas our earlier company, TSR Technologies, was kind of a "me-too" product with a little bit easier-to-use interface.

Question: Where did you get the name Wireless Valley?

Answer: Well, Blacksburg sits in a beautiful part of the world, sort of a valley between the Appalachians and the Blue Ridge Mountains, and it's absolutely gorgeous here. When we started building the wireless program, I started calling the area Wireless Valley. Students really liked the nickname — in fact, we had sweatshirts we printed up in the early nineties that say, "Building the Wireless Valley." This reflected my hopes for the region, that academic core technologies from MPRG would lead to the start up of a number of wireless companies. So when we started Wireless Valley, the company, we trademarked the name.

Question: I see Wireless Valley offers a lot of hardware in addition to the software products that work with each other for doing measurement and channel sounding.

Answer: Exactly. What we've brought to the industry, and have protected by patents, is the novel idea of multi-faceted software that can integrate with many different hardware products for many applications. Wireless Valley's core competence is development of powerful and easy to use software along with great knowledge of the issues that people have to design and manage wireless networks. If we wanted to, we could do consulting morning, noon, and night, but we've chosen not to — instead, we've chosen to serve the industry by making products that can allow other people to be the experts. Our products, such as SitePlanner®, InFielder PDA®, LanFielder® and SiteSpy®, build in a ton of knowledge into expert programs that are easy to use. By the way, we've just issued new releases of these products this month. We have over 150 customers worldwide, and universitites are starting to use these products to build networks and teach new wireless courses.

We don't manufacture hardware ourselves, but we work with a lot of different hardware providers, we partner with them, such as Anritsu or ZK Celltest, Praxsym, Dynamic Telecommunications, Inc. (DTI), or Berkeley Varitronics, so their hardware will plug and play instantly with our software products. We also have a good agreement with Ciscoand the other Wireless LAN card vendors, and our products work instantly with every 802.11b WLAN modem, bluetooth, and even wired IP-based nodes, too. The idea here is you don't have to buy new hardware — our SitePlanner® program, for example, will help you design and measure, as well as manage and archive all of the information related to your network. Just plug it in to what you have already.

That's what's always been missing in the wireless industry, how to maintain and manage knowledge of many different people. And that's the key behind SitePlanner®. The way we learned to do this was from trying to maintain research knowledge gained by students who learn a core knowledge and then graduate and leave us. We'd have a great project going on a new frequency band, or an NII study at 5.8 GHz for residential wireless, for example — the students would make their measurements, generate their models, do their designs, learn all this great stuff and then graduate. Well, a new student coming in doesn't want to pick up the custom code or the custom knowledge that's been spread around in different spreadsheets, theses, papers, and a whole bunch of notebooks. The past knowledge base is lost, as it the measured datAnswer: To rectify this loss, we designed a system that will help us share, archive, manage, and grow knowledge and information.

And then we realized, that's exactly the same problem in the wireless industry! People change jobs, people move, people forget what they've done — and this is the same as the problem I was having as a Professor! But no one's ever solved this problem in the wireless networking industry — the cradle-to-grave information management problem. When you do a measurement, a bid, a deployment, a cost analysis, something breaks — you need all this information if you are a carrier or a manufacturer. And that is what SitePlanner® does — it handles all that. It does it in an easy-to-use, well-organized way so that we have the equivalent of a visual spreadsheet, where you can visualize the entire network in a campus or building or group of buildings. You can see it in 3D, see where the components were placed, right in the blueprint, see what it cost, see where it's been repaired, instantly see the measurements you made when you were on-site with that system, and it can update and archive all that information. So, you can pass this information from the consultant or installer to the person who owns the network, to the person who has to troubleshoot the network, and it doesn't matter if one of those people leave or forget what they've done. That's revolutionary! It's never existed! We have put this knowledge on palm pilots, on Ipaq computers, and on PCs, so that an enterprise or worldwide staff can now use the internet to manage this type of information.

Interestingly, we're getting interest in our products not only from wireless companies, but also from wired companies wanting to know where the wire was put in and where it was placed. And this all came from trying to grow a research program, and trying to keep and maintain the knowledge to try to grow the program.

Question: What do you see as the trends in wireless today?

Answer: We're in the convergence of wireless LAN, in-building wireless, broadband indoor, and the cellular systems trying to get indoor, and I think that's going to be the huge battleground over the next few years, who controls the wireless access in buildings.

Question: Do you think the 802.11 type stuff will be dominant there?

Answer: I think it's going to have a definite role. Whether it dominates or not remains to be seen, but I think it's definitely a contender. What I'm hearing in the industry is a convergence between 3G mobile and 802.11 wireless type products.

Question: I've heard that 3G is sort of getting pushed to the back burner because of the explosion in 802.11. Have you seen that?

Answer: I've heard that, but I think 3G is getting pushed back even more because of the 2.5G alternatives that have been coming out. The installed base for cellular is so big now, over 630 million phones, and they're a captive base of monthly subscribers, so anything that gives a data offering in cellular is in immediate demand and immediately keeps customers on the network. So I think the carriers are pushing 3G off a little because they can keep customers paying the monthly bill by giving them things like GPRS or a high data rate on Qualcomm's CDMA. So this forces the WLAN makers to figure out how to unify, and that's starting to happen. The problem with 802.11b is there's no worldwide structure trying to unify and standardize them all — it's starting to happen with BRAN in Europe and 802.11g and 15, but it's in the early stages. I think if the Wireless LAN folks get their act together they could dominate indoor. After all, indoor environments are the only ones where a user can actually digest huge datarates. You don't need them driving a car.

Question: What kind of advice would you give to people setting up large Wireless LAN systems? What would you tell people they need to do first?

Answer: Good question. First bit of advice: use a computer aided design software program to plan out coverage and to handle cost analysis and frequency planning for your network. This is something the cellular people learned they had to do, but the wireless LAN people haven't figured this out yet. Now granted, cellular base stations are more expensive than wireless LAN access points, so people will resist this argument, but there is tremendous value in doing some quick engineering analysis using a computer aided design tool before you set forth into the campus or buildings. It's like using a spreadsheet to estimate a large project — you can't really eyeball a complex system. What is happening today is that people will go out with rough rules of thumb, without really considering the buildings they're going into, and they will sort of randomly place access points where they think they belong, based on their intuition or some simple number. And that's OK if you have just a few access points, just like it's OK to use a hand calculator if you have just a few calculations, but the IT community really needs to move to a computer aided design environment like SitePlanner® because the networks are going to get a lot larger, and there will be more users, and more interference, and more management will eventually be needed — all the access points radiate energy, cause interference, and rely on power, and they will all break eventually. You need to know where they are, what they cost, how they work, and who put them in.

The value in doing strawman designs in a computer aided design platform is that your blueprint can give you so much information, and can get you to a better design before you just start plunking access points into the network. The cost savings for larger networks will be tremendously great.

My second bit of advice, and this is even more valuable than the first: use a computer aided design environment to archive your design, component placement, and network performance data. The advantage of this is that you build knowledge and informed intuition very quickly with the software bringing you up on the learning curve on network design, while at the same time the software can be used to archive where you've put the hardware. Knowing where you put the antennas above what raised ceiling is invaluable -- as indoor wireless networks proliferate, this is going to become the biggest problem of all. Imagine access points that are above raised ceilings that may start emitting spurious radiation. If you've got to go find that with a power meter, you're going to waste so much time walking around in a building. We can put that information on a palm pilot so you can go right to the spot. Also, suppose your user community builds, and you want to get more people on the network. Interference managing is going to become such a problem in high density WLANS that you're going to have to have a computer aided design environment to know where you put the components and to manage spectrum! But most indoor wireless networking companies don't understand that yet because there just haven't been enough large installations. Microsoft, by the way, has one of the largest WLAN installations to date, and they are getting SitePlanner® to manage their network.

Question: Do you think the move to 5.8 GHz and 802.11a will push even harder on that?

Answer: Yes. With 802.11a, you're going to decrease the range of access points because of the wider bandwidth. So you're going to have more access points per building, and initially the 802.11a equipment is going to be more expensive, so a product like SitePlanner® can instantly save you money on the deployment. As people start deploying 802.11a, I think you'll see the popularity of wireless LANs increase tremendously, so there will be more access points, more mobile users, more interference, and more issues to manage. So going out with a best guess and just throwing 'em up in a building isn't going to work anymore.

Question: How about UWB? Is any work going on at either MPRG or Wireless Valley on this subject?

Answer: We're in close contact with the UWB community, we're excited about it, and think it will be viable. The thing that holds it back commercially is the FCC and FAA regulatory issues. We think eventually UWB will be allowed.

We're not directly doing UWB research, but since our work at the University is fundamental — i.e,. when we're doing channel modeling it's generally of a fundamental nature with as much bandwidth as possible — a lot of our research is directly applicable to UWB. For example, at MPRG we have a 1 GHz bandwidth channel sounder that does full I and Q modulation and demodulation. This is 1 GHz on an RF carrier that we can vary from 2 GHz up to 60 GHz, so when we make channel measurements and channel models on path loss or for time delay or angle of arrival, all of that information is useful to UWB because we're able to resolve things to a 1 nanosecond resolution. So therefore, our work directly benefits UWB proponents.

At Wireless Valley, since SitePlanner® uses fundamental propagation models that are frequency independent, the good news is that it works for UWB already and we have some customers who are doing UWB and who are designing their systems and their coverage using SitePlanner®.

Question: Have you made any comments to the FCC in response to the Notices of Proposed Rulemaking or studies on UWB?

Answer: Not directly, no. But several companies have asked me to provide information on propagation and RF bands as part of their commenting process, and I have done that. I don't know if those companies have used my name in their comments or not.

Question: From looking at your website and seeing all the things you're involved in at MPRG and Wireless Valley, it's obvious that you have boundless energy. Are you involved in other things as well that we haven't talked about?

Answer: Well, my wife and I have 3 children, the oldest is in college and I have two girls at home that keep me on my feet. But I'm also involved in a barbershop quartet. It's called the Uncalled Four (as opposed to Uncalled For), and I sing lead tenor and sure love that. Also, I really enjoy the students, and try to help them out and find them opportunities to learn both in and outside of the classroom. And I really like interacting with engineers in the "real world," through Wireless Valley or through email conversations. That keeps me pretty busy!

Question: Well, you're certainly in the forefront of what's happening in the wireless field!

Answer: It's a lot of fun, it's a great career, and I've been tremendously blessed!

Dr. Rappaport, thank you very much for talking with us!

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020