Wireless technology: Too many options

Gone are the days when employers handed employees mobile phones for mobile communication and laptops for Internet access via the telephone network. Now users stand in front of too many choices when they need a wireless device.

In addition to Wi-Fi wireless local area network ⁽¹⁾ and mobile data that are growing rapidly, there are currently two new options using OFDM system ⁽²⁾ (Orthogonal Frequency-Division Multiplexing): Mobile WiMAX ⁽³⁾ and FLASH-OFDM (Fast Low-latency Access with Seamless Handoff-OFDM).Mobile WiMAX is most heavily marketed, while FLASH-OFDM has been deployed and is now owned by mobile communications group Qualcomm.

The problem between Wi-Fi technology and mobile cell technology is the problem between speed and coverage.Public Wi-Fi hotspots (hot spots) can allow users at Internet cafes or airports to connect at several megabits per second.Therefore, determining the IEEE 802.11n ^{(4) standard} for wireless local area networks is aimed at speeding up the connection to about 100 megabits per second, while improving coverage.

Mobile data service 3rd generation (3G) ⁽⁵⁾ is capable of covering an entire urban area. More and more US metropolitan areas are covered by 3G networks. For example, Verizon Wireless currently offers high-speed EV-DO ⁽⁶⁾ (Evolution-Data Optimized) CDMA mobile service in 84 US markets, while Sprint Nextel Group provides translation. This case is in 75 markets.Sprint Nextel plans to upgrade the network gradually to the next version of EV-DO, Revision A, by the end of 2006 and early 2007. Verizon will also switch to Revision A but has not disclosed the time.It is expected that the new version of EV-DO will make the upstream connection speed significantly increased.

On the other side of the 3G wall is Universal Mobile Telecommunications System UMTS ⁽⁷⁾ - a system that is considered a stepping stone in the GSM system upgrade plan of Cingular Wireless LLC. According to Ritch Blasi, a Cingular spokesman, the UMTS system is available in six US markets and this number will increase to 15 or 20 by the end of the year. The company will use a new version of this technology, called HSDPA ⁽⁸⁾ (High-Speed ​​Downlink Packet Access).It matches the average connection speed of EV-DO system.(All 3G networks have a dramatically increased connection speed in places where there is less congestion.)

Blasi shows two special features of the UMTS system compared to EV-DO.First, UMTS transmits audio and data, so users can both make phone calls and connect to the Internet on the same device and this system is widely used outside the US.In the first half of 2006, Cingular plans to launch a PC Card UMTS modem with dual band that allows users to connect to the network inside and outside the US.

3G technology is currently being integrated into mass-produced laptops.Dell has just made people pay attention when announcing plans to work with Verizon to produce laptops using EV-DO systems and link with Cingular to produce HSDPA systems (new versions of UMTS). .More and more portable devices use 3G technology.Treo-branded phones installed with Microsoft Windows Mobile software recently announced by Palm will use Verizon's EV-DO network technology.

Mobile WiMAX - a fixed and expected variant of WiMAX expected later this year - is currently backed by Intel but cannot be delivered before 2007. According to Intel, as well as Wi-Fi, mobile WiMAX will be successful thanks to high output and global compatibility, although problems related to standardization and frequency of radio waves need to be further resolved.

Proponents claim that mobile WiMAX technology allows wide-ranging coverage in large cities to facilitate users who frequently move from one place to another for easy network connectivity but with faster data access speed than 3G and better multimedia applications.According to some observers, the majority of mobile service competitors not using 3G technology will turn to WiMax technology applications.

Flarion Technologies Inc.has pioneered the application of Flash-OFDM.Earlier this year, Qualcomm reached an agreement to buy the company.Flarion's networks have been deployed by several service providers and are the focus of testing by other service providers like Nextel Communications Inc.They are designed to have a mobile WiMAX connection speed and can run well on different frequency bands.

Bob Group's analyst Bob Egan advises that laptops should be equipped with Wi-Fi technology because it is the best way for employees to stay on the network when at home and in the office. different rooms.However, there are ways to handle high-speed data while on the road better than using Wi-Fi at the wireless Internet access point, he said.

According to Egan, wide-area wireless access is likely to become the best long-term solution.Until widespread, mobile WiMAX will not have a big advantage in performance or price compared to 3G, he said.However, he advises not to buy a laptop with built-in 3G card.The best way is to purchase a PC Card modem separately because when there is an improved network technology, such as EV-DO Revision A, 3G technology will be eliminated, he said.
3G cards that mobile service providers currently sell to customers are locked, using only the internal network.Therefore, company customers will have to sign long-term subscription contracts to enjoy reduced prices.From Egan's point of view, there is only a way to end that kind of business - but remember it is not easy - it is possible to change the balance for corporate customers and competitors using the WiMAX system.

Current Analysis analyst Eddie Hold at Current Analysis agrees that buying a 3G radio laptop that is locked by a mobile service provider to connect to another network will make the company customer vulnerable. tie.But he did not agree with Egan's view of the overall strategy.Because PC Card modems used for EV-DO systems make laptops run out of battery faster than Wi-Fi attached to the computer and have lower performance, Hold said.

Hold's advice should only buy 3G cards for some employees who really need it.Most employees can still finish work in places where Wi-Fi is available, he said.

Later, companies can buy a combination of connection technologies.Sprint Nextel currently has a license to own a variety of technologies on most US land and these technologies can be approved for mobile WiMAX applications.

(General Minh Khoi)

⁽¹⁾ Wi-Fi (Wireless Fidelity): Trade name for product compatibility standards for wireless intranet. It allows mobile devices such as laptops and PDAs to connect to the local network, but is currently commonly used for Internet access, wireless VoIP calling.
⁽²⁾ OFDM (Orthogonal Frequency-Division Multiplexing): A transmission technique based on the idea of ​​frequency-division multiplexing (FDM). In FDM technology, many signals are sent at the same time but on different frequencies. In OFDM technology, there is only one device that transmits signals over many independent frequencies (from a few dozen to several thousand).
⁽³⁾ Worldwide Interoperability for Microwave Access: WiMAX is similar in concept to Wi-Fi but there are some improvements to improve performance and allow connection at longer distances.
⁽⁴⁾ IEEE 802.11n : A new addition to the IEEE 802.11 wireless LAN set of standards by the Working Group of the Local Area Network (LAN) / Urban Area Network (MAN) of IEEE ( American Institute of Electrical and Electronic Engineering built). The 802.11n standard will make the network work longer than current networks.
⁽⁵⁾ 3G : 3rd generation mobile technology. Services using this technology allow audio data transmission (calling) and no sound (such as downloading information, exchanging information). e-mail and texting.
⁽⁶⁾ EV-DO (Evolution Data Only / Evolution Data Optimized): Wireless broadband data protocol. Currently many CDMA mobile service providers in many countries around the world apply EV-DO, including Venezuela, Mexico, Brazil, Japan, Korea, Israel, USA, Australia and Canada.
⁽⁷⁾ Universal Mobile Telecommunications System ( UMTS ): One of the three current mobile technologies. UMTS is sometimes called 3GSM to distinguish it from other networks and emphasizes the combination of 3G nature of this technology and the GSM standard.
⁽⁸⁾ HSDPA (High-Speed ​​Downlink Packet Access): New mobile protocol;Also known as 3.5G (or '3½G').