comms & networking
Qualcomm Beefs up CDMA for 2.4Mbps Wireless Internet
In November 1999, Qualcomm, Inc of the US demonstrated its test system for high data rate (HDR) wireless datacommunications, designed for Internet connection. Chairman and chief executive officer (CEO) Irwin M Jacobs expressed confidence in the widespread adoption of HDR, claiming, "HDR perfectly fits the demands of the market today for high-speed Internet access."
Jeff Jacobs, senior vice president, Business Development, who is in charge of the HDR project, explained that plans call for system capacity tests in the first quarter of 2000, followed by technical evaluations in the second quarter, market evaluations in the fourth quarter, and the provision of a commercial service in the second quarter of 2001.
HDR is based on the code division multiple access (CDMA) technology (developed by [Qualcomm http://www.qualcomm.com]) already in use in mobile phones and other systems, but Qualcomm says the intended application for HDR is Internet connection. It uses the wireless frequency only at the time of receiving or sending data, a design measure specifically developed for the intermittent demands of Internet access. Various functions such as power management for conversations have also been omitted, making it possible to allocate the entire 1.25MHz bandwidth of the current voice system to datacom use.
As a result, datacom speed peaks at 2.4 Mbits/s for the downlink (base station to terminal), with an average of 600 kbits/s, and 307 kbits/s peak, and 220 kbits/s average on the uplink � a system of asymmetric communication. In addition to making high-speed datacom possible without increasing the frequency bandwidth, it also makes it possible for carriers to keep equipment investment down, because inexpensive Internet routers can be used for the trunk system. In other words, the existing cdmaOne network can be provided with functions for high-speed datacom with only minor modifications.
Demonstrations were held making use of two types of communication environments: a fixed environment representing the home; and a mobile environment simulating automotive use. For the former environment, five personal computers (PC) and a wireless system were installed in a hotel room, while for the latter, two vans were fitted with PCs. Two base stations were located near the hotel. The room demonstration used a base station about 2.4km away, while the van used both base stations.
Applications demonstrated included a World Wide Web (WWW) browser, transmission of e-mail with attached files, file transfer and the distribution of music and video streams. Among these, the video distribution demonstration hit an effective throughput of over 1 Mbit/s.
The prototype wireless system consisted of a box provided with interfaces for Ethernet (10BASE-T), universal serial bus (USB) and RS-232C. The firm plans to develop, in the following order, a version that can be mounted in a mobile phone, a PC card design, and an interface board for use in PCs and other information systems.
According to Qualcomm, the peak performance for the test system is 1.8 Mbits/s, although this drops to an effective rate of 100 to 300 kbits/s for WWW browsing and file transfer, in which transmission control protocol (TCP) is used as a lower protocol. The drop in speed is a result of the TCP waiting for receipt acknowledgement before sending the next packet of data.
As the hotel was the only tall building in the region, the wireless communication environment was close to optimal. Paul E Jacobs, Consumer Products president, explained that in the urbanized region where transmission paths are poor "communication reliability can be assured by increasing base station density and using smaller cells."
Timed to coincide with the demonstration, Qualcomm also announced two new chips that support HDR: the iMSM4500 and the iMSM5500. They will sample-ship in the fourth quarter of 2000 and in the second quarter of 2001, respectively.
The firm has also developed business simulation software for communications carriers interested in evaluating potential HDR services. The simulation accepts a number of parameters, such as the population covered by the HDR infrastructure after three years of implementation. HDR aims at three market areas: Internet connection from notebooks; from personal digital assistants (PDA) other than notebooks; and in fixed environments such as from desktop computers. The utilization ratio for HDR can be forecast for each year and group, and a profit break-even line can be calculated.
Some American carriers are said to have already begun business evaluations using the simulator. "Our expectations are especially high for the Asian region, where competing high-speed Internet access technologies such as ADSL (asymmetric digital subscriber line) and cable modems are relatively uncommon," said Qualcomm Business Development senior manager Herbert Vanhove.
(Takahiro Kikuchi: Feb. 2000 Issue, Nikkei Electronics Asia)