lul Dr. Plasser Modiri Network Equipment Technologies. lnc 800 Saginaw Drive. Redwood City, CA 94063. USA ABSTRACT Within the last two years there have been many ad- vancements in the development and deployment of por- table computing products. The potential offerings of por- table computing have been mostly noticeable in the areas of Cellular Communications, and Wireless Com- munications technologies more recently. Wireless Com- munications is still at a very early age, however, many major international corporations have started to deploy this technology in specialized applications now. This paper provides an overview of the technologies of the Cellular Communications and Wireless Communi- cations. The advantages and disadvantages of both technologies are discussed. A survey of some typical laptop computers is provided which perhaps is the single most important factor that has made portable computing widely available to many mobile users today. eywords: Cellular Communications, Local Area Net- work (LAN), Point-of-Access (POA), Public Switch Telephone Network (PSTN), Read News (RN), Spread Specturm, Wireless Communciations, Wireless-LAN, Wire-based LAN. and cost savings can be achieved by many business. Fig. 1. illustrates the estimates of mobile computerwork- ers. : Portable Computing Figure 1. Estimates for Portable Computing. INTROD UCTlON A~c~r~ing~o the US Department of Labor, there are over million mobile workers today in the United States, and million other workers who have the potential to be- come mobile [I .]. However, there are many other work- ers who would like to become mobile, in terms of being to accomplish part or ail of their allocated tasks at e, or a place not bound with the need of their office computing power. There are 120M workers in the USA, and some 13M of them change their jobs per year many of them involuntarily, more of these WoFkerS could have kept their job if there were mobile. Therefore, being able to change the physical location of a client on a day-to- basis is a very impo~ant factor in SS~S to take adva cal and service-sri ngineers who have to the Internet's y typically spend 8% of their ewsgroups on adaily basis. if e to ac~ess the Internet re- vendors have recently developed portable laptops and modems to enable a remote off ice employee to commu- nicate with the corporate office. The employee is able to link up with the corporate or Headquarter (HQ) to be up- diated with. for example, the latest news about product delivery and schedules. Tlherefore, this new trend has enabled mobile employee:; to leave their big corporate offices and work remoteiy from ihe comforts of their home [2.]. It is estimated that the 30 r;nillion--pius mobile workers market is the next biggest market for the computer in- dustry to exploit in :he next 2-3 years. It is the portable computing together with wireless networking which comprises mainly the users of this market [3]. However, the portable computing market is not yet monolithic, and inlact in many aspects needs its requirements to be spe- and ~~ch~ol~gy inde- cified on a national. multina.tional. pendent way. Thiis paper is comprised of 3 sections. Section 2 pro- vides a description of portable computing when used in CeIIular Communications ,and Wireless Communica- Tb meet the needs of the new mobile employees many tions technologies. Section 3 concludes the paper with discussing furtherthe pros and cons of portable comput- ing and predicting the future of this technology. TABLE COMPUTING: Cellular Communications In 1991 5.1 M computers were sold in the USA. approxi- mately 509 thousands of which were laptops. It is ex- pected that the number of laptop (and palmtop) comput- ers sold in the USA to increase by 28% for 1992. It is important to note that portable computing is not just bound by laptops or palmtops. Another equally impor- tant area of portable computing is the development of Radio-Connected computers (4.1 which is discussed in the next section under the Wireless Communications heading. Typically, these are hand-held computers which, for example, help sales people dial into the com- pany mainframe and place an order on site, as shown in .~ Fig. 2. The basic elment for a corporate traveler to become mo- bile is a laptop. The requirements fora corporate traveler to communicate with the HQ is a modem and a connec- tion to a Public Switch Telephone Network (PSTN). This connection can be made, for example, by using a cellular phone, as shown in Fig. 3. However, the connection be- tween the laptop and modem to the cellular phone may be made via a Cellular Jack. The industry standard tech- nologies which are enabling an employee to become mobile using Cellular Communications technologies are: Figure 2. Communicating via Portable Com- puter with LAN+ased Access Resources. DATA - Data communications can be achieved via V.32bis, V.32, V.42bis, V.22bis, V.22, bell 21 2, or Bell i no I u3. 0 Fax - Fax transmission/reception can be achieved via Group 3 Class 1 and 2, V.17, V.19, or V.27ter. Cellular - The standard Cellular technology is MNP-10, however, there are vendor Cellular technologies also available. 0 LAPTOP MODEM CELLULAR PHONE 0 ., SATELLITE DTE Figure 3. Remote Portable Computing. Some advantages of using Cellular Communications is: Boosting Productivity Saving Time and Money Convenience Flexibility 0 Environmental Considerations - Using laptops can actually leave alone the environment that we are living in, since there is no requirement for ex cabling. In the long term the cost of m company can actually be reduced, since the 1Q of cabling required to set a network of portable computers will be a minimum. and the requirements for building sublayer floor or ceiling to accommodate the cabling will almost be eliminated. Remote Management another explosive expansion in the development and now deployment of Local Area Network (LANs) [5., 6.1. However, it has now become more difficult to manage the LANs and it associated resources from a remote site. It is through either the distributed or hierarchical network management that the resources around a network can be managed (i.e., monitored, and controlled). Providing portable computers to corporate officers is easy, but be- ing able to be in communications with them is not an easy task. and hence a mechanism needs to be deployed to enable a HQ employee to contact the re- mote employee when a needs arise. An easy method to achieve this goal is to incorporate the functionality of a Pager into the new portable computers. In the past two years the computer industry has seen Communications With the need for portable computing the Wireless Com- munications and wireless LANs have seen a great growth in the past year [7., 8., 9.. 1 O., 11 .]. Although, the standards for Wireless Communications is still in draft format (currently the IEEE 802.11 technical committee is working on the protocol specifications for Wireless LANs), many vendors are now retailing wireless prod- ucts, such as wireless Bridges and hand-held Point-of- Access (BOA) terminals. It is possible, for example, to remotely access the corporate server or host-based systems from a simple POA terminal. Hence, makingthe database of the corporate office available to virtual ter- minals (POA). These POAs can be moved anywhere (within their range of operation), any time without requir- ing any wiring. Complex network environments may use a multitude of networking products (LAN-based and Wireless) and in- ternetworked to a multitude of other private or public networks, as shown in Fig. 4. Wireless communications bridges can significantly reduce the effort required to in- terconnect the remote sites and eliminating the environ- mental obstacles which may exist when requiring to in- ternetwork a multitude of such remote sites. Even though, the usage of Wireless Communications is still at its very early days, its cost today is not much more significant when compared to the cost of installin re-based LAN in an organization. The cost of placing a wire-based LAN in afl organization where the @m- plcryees may be exposed to, for example, embeddedas- based and Wireless Networking Environment. bestos in the walls can tie very much. Other consider- ations are: 0 Initial costs of installation 0 Organization shutdown Planning costs 'D Decoration costs - set up required for a point-of- access 'The Wireless Communic
