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Home Page Editorial
15,  2001)

From Publisher and Managing Editor's Desk... 

Should the Telecom Industry Rethink Architecture of its Wireless Networks? Does a Hybrid Network Consisting of Wireless LANs and Wireless Wide Area Networks Make Sense? 

During the last one year, we have seen many changes in the high-technology, Internet and Wireless space.  The stock market's collapse has done a great deal of good to the processes that were used by VCs and market research companies to promote new technologies and startups. The Internet has come down from the stratosphere to terrestrial orbit. The debt load of wireless operators and soft financial markets have moved the focus from more expensive 3G to affordable 2.5G implementation strategies. Whereas 3G networks may be delayed, wireless LANs in hot spots may fill the void. 

Against this background, MobileInfo.Com recommends a re-evaluation of the architecture of  integrated networks for mobility. We are suggesting that the current network architecture where we expect wireless wide area networks to serve the entire needs of mobile workers and enterprises should be replaced by a hybrid network architecture consisting of public shared  or private wireless LANs and public-shared wireless wide area networks. Here is our technical and business rationale for recommending this approach. We are also making some suggestions to the industry power houses to seriously expedite research into making this happen: 

  1. In our proposed mobile network architecture, wireless LANs (both private corporate LANs and public shared "hotspot" wireless LANs in hotels, plazas, airports, gas stations or other business centers), fixed LANs and public-shared wide area wireless networks will form one composite and seamless network that will connect with backend information reservoirs through the Internet. All mobile devices under this architecture will have a network adopter that will utilize software radios to tune to a wireless LAN or WAN as the case may be, depending on whether you are in the coverage area of the LAN or the WAN. The devices would roam in various networks. The software in the handheld device will dynamically load drivers to connect the two ends of the application. The connectivity software and application interfaces will maintain the logical connection while switching from one network to the other.

  2. This network architecture will provide high-speed (IEEE 802.11b LAN speed @11 Mbps possible today and up to 54 kbps in future) access within the hot spots and lower speed (56 Kbps to 384 Kbps) when outside the coverage areas of the LAN by utilizing 2.5G GSM/GPRS or 1xRTT CDMA networks now and full-fledged 3G networks in future. Bluetooth technology will also be a component technology within this architecture to allow handheld devices to connect to kiosks and stationary servers within hotspots. As Bluetooth becomes more matured, it will be another incarnation of wireless LANs as is the case in the eyes of IEEE standards community. We agree that power requirements and cost are in favour of Bluetooth but distance limitations are not. For more pervasive smart phones, IEEE 802.11b adapter may be over-kill. Network designers can make that choice in configuring the hotspot network design.

  3. From a user's perspective, the device will tune into a hot-spot LAN when you enter coverage area of the local LAN. At this location, the user could do Internet information related work in a more relaxed environment (as compared to what is possible in the car) by accessing remote information systems. Later as the user goes on to his/her next destination, he/she could still stay in touch even though LAN signal fades away but now you are under the control of a public-shared wireless WAN.

  4. This architecture is consistent with one important business requirement reality that is often ignored by network infrastructure providers who have greater self-interest in wide area network infrastructure sales than in LAN hardware sales. This business reality is based on what we call "mobile-aware" lifestyle (as defined in Chapter 11 of our book "Mobile Computing -Systems Integrators Handbook"). This mode of human functionality simply states that you can not function effectively and efficiently when you are in motion. Your power of concentration (more visual than audio) is much lower under such circumstances. You general want to access summarized information rather than huge amount of data. Multi-media messaging can be useful but as an exception rather than a rule. Therefore, your wireless data bandwidth needs are lower when you are in motion than when you are stationary though away from your normal stationary place - mobile but fixed. The latter requirement can be met more easily when you are in a comfortable spot like a hotel, coffee shop, restaurant, airport  or plaza - so called hot spots.

  5. Cost for delivering a megabyte of information using a wireless LAN as edge network will always be cheaper than delivering it by using a wireless WAN as an edge network. Since we have greater data transfer requirements when we are mobile but stationary than when we are traveling in the car, our wireless data needs and network delivery economics are in correct alignment.

  6. Most of the component technologies required to put this hybrid network architecture are already in place.  One piece that does need more research and development is the software radio controlled multi-network adapter for the mobile devices. Even here, companies like Padcom have demonstrated the technical feasibility of our proposed approach. Furthermore, we do expect rapid development of this component as we see several companies developing multi-radio, multi-network chips. 

  7. The most difficult obstacle that we see in our proposal is the opposing self-interests of wireless cellular network vendors and the wireless LAN vendors.  The wireless LAN vendors will support this quite naturally because they will gain a lot with the adoption of this proposal. It is our hope that Motorola, Ericsson, Lucent, Nortel and others will ultimately see the merits of this proposal sooner than later.

  8. This proposal of hybrid location-aware network architecture addresses spectrum shortage problem as well because in densely-populated areas, wireless LAN-based hot spots will be the carriers of this traffic, leaving much-needed capacity for truly mobile workers in their cars. 

  9. We do not subscribe fully to a recent analysis by Merrill Lynch suggesting that huge amount of debt by telecom operators and equally huge need of capital for 3G should lead to abandonment of 3G. The analysis is somewhat shallow and suggests a monolithic solution to a complex problem. We strongly suggest that we have to move forward on both fronts - wireless WANs and LANS. This means that we should continue to implement 3G networks where it makes economic and business sense (e.g. in Japan, Asia and parts of Europe), upgrade to GSM/GPRS where that is the most cost effective option, not abandon a superior technology like 1xRTT CDMA in those cases where the operator has a CDMA network already. In USA, we should continue to experiment with 3G in selected markets. However, while we implement this 2.5G/3G wide area wireless strategy, we should divert significant funds for wireless LANs in hot spots. 

  10. We suggest that network operators and infrastructure suppliers should realize that they need not fear wireless LANs that can be complimentary to their wide area wireless strategy. They should also appreciate that the laws of radio spectrum physics, limited nature of spectrum availability especially in developed countries, increasing gap between capacity and speed of fixed line versus wireless networks, demand for greater bandwidth in hot spots and natural human behavior of herding together in hot spots (mobile but confined to limited campuses) rather than on highways would result in natural economics being in favour of  wireless LANs as compared to wireless WANs. Therefore, they should not fight against this trend but instead join forces by investing in hot-spot infrastructure. 

Chander Dhawan - Your Site's Principal Consultant and Publisher

Do you want to make any comments on this editorial? Submit your Comments. 

See what BWCS Study says on this subject.

Readers Comments

" Wireless carriers fragmented – will find it difficult to get into hotspot market"

"How do you see as being the winners/leaders in the development of public access wireless based on 802.11? Domestically, Internationally? I agree with the hybrid concept, and the hot spot space will be 802.11-enabled before 3G gets its act together. But the wireless carriers are fragmented, undercapitalized. Will they struggle until the big carriers decide to get into to it? Will a new one emerge with right capitalization and business model to aggregate local carriers?" - Leslie Latham, Consultant

"Chander I agree with your comments 100% and also agree that we should make the best out of what's with the real today. Our company ipUnplugged AB is HQ in Stockholm, Sweden and formed by senior research and development guys from Ericsson Radio. Actually the CTO was the Chief Architect for GPRS within Ericsson Radio.

Please feel free to visit our website at . We have real shipping products that’s based on standards and specified in 3GPP and 3GPP2 , but can also work in both the enterprise and/or public enviroment. We can make this happen to today and in the process of building the relationships to make it happen." - Ibrahim Al-Islam, IPUNPLUGGED

"Your analysis in the Aug 8 editorial is right on target. Some key building blocks for hybrid networks are already in place: 2.5G networks such as GPRS are rolling out, and so are WLAN hotspot networks such as MobileStar in the US and Telia Homerun in Sweden. Also, multi-access devices are available as all major notebook PC vendors are integrating WLAN and Bluetooth in new models, and some promising PDAs in the market, such as Sagem"s WA3050 with GPRS built in and a compact flash slot for a WLAN card.

In my mind, remaining barriers to hybrid networks that need to be resolved are:

  • speed of GPRS roll-out
  • price and performance of radio cards
  • the legal status of commercial WLAN networks in some EU countries, such as the UK
  • finally, we need to get mobile operators (real or virtual) to market hybrid networks as a packaged service, easy to install with a logical pricing scheme. It will never take off if it remains a DIY project for mobile enthusiasts. The first three points should be solved in the near future, and then we are really waiting for an initiative from the mobile operator community." - Pontus Bergdahl, CEO, Columbitech

"I am surprised that there was no mention of Bluetooth as a hot-spot technology. Data rates and power consumption are much more compatible with the handheld devices of today/tomorrow. Bluetooth data rates will still meet or exceed much of the 2.5 and 3G technology while providing a more flexible wireless solution supporting voice, data, cable replacement etc. I would be interested to hear you opinion on this subject." - Bob Gessel, CEO, MobileStream Wireless


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