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8 1X Technology and GPRS/EDGE/W-CDMA—the upgrade path Andy Singer, RFS Americas Director Marketing & Technical Services explores the challenges facing North American cellular operators as they approach the 3G age. As wireless systems evolve globally, there are numerous trends that are leading the ‘wild wireless world’ down the road to 2.5G, and later to 3G technologies. Our society has quickly become computer literate, with increasing demands for information when and where required. Wireless technology use has increased greatly, with penetration rates in some regions as high as 80 per cent. These same users have adopted the Internet and its many useful capabilities. Technologyenablers, such as wireless/portable palm-type devices and high-speed data networks, will soon help meet society’s growing needs, by providing consumers with enhanced services and applications. Throughout this process, the needs of the stakeholders must be ensured—specifically the needs of users/consumers and the wireless system operators. The needs of the consumer include a reliable feature-rich service that provides quick and portable access to voice and data at a low cost. The key consideration for operators is the cost of effectively migrating to these new systems, and ensuring that roll-out of such services is achieved quickly. These needs are technology independent. Wireless/3G obituary? There are currently some consultants who have forecast almost the equivalent of an obituary for wireless growth and 3G systems. Radio Frequency Systems takes a far more positive view of this market. Due to constant drivers—such as continuous growth in subscriber numbers, the increase of minutes of use and consumers’ desire for Internet-based services—we believe that consumers, like ourselves, will exhibit an insatiable demand for advanced features and services. While some operators may find greater financial reward in deploying 2.5G solutions initially, and then deploying 3G in later years, we feel that wireless growth over the next decade will continue at a great pace. Fortunately for North American operators, there are various upgrade paths towards 3G. For the Code Division Multiple Access (CDMA) operator—sometimes known as IS95A or cdmaOne—the path consists of a series of steps along the 1X technologies CDMA2000 route. These are the 2.5G 1XRTT, followed by the 3G stage 1X-EV DO, and then 1X-EV DV (see Table 1). The table lists the theoretical maximum data throughput rates for each technology. Naturally, field tests are currently showing a range of throughput results below these theoretical maximum, but all ‘real world’ field throughputs expected to improve as systems are optimized. For Global System for Mobile Communications (GSM) the path is identical to that we described for European GSM operators in the last issue of STAY CONNECTED. For Time Division Multiple Access (TDMA) IS54/IS136 operators, the path is almost identical to that of GSM. This path will consist of the Enhanced Data Rate for GSM Evolution (EDGE), and then to Wideband Code Division Multiple Access (W-CDMA). The complete upgrade path time line ‘map’ is described in Table 1 for all three digital standards. CDMA, TDMA and GSM operators all have a very robust, flexible and efficient upgrade paths to 3G. 1XRTT by 2001 A typical CDMA operator will be capable of deploying 1XRTT by late 2001. The upgrade path to this 2.5G technology only requires software upgrades and the replacement of the channel card at the operator’s base stations. 1XRTT will provide the operator with approximately double the voice capacity and an advertised data rate of 144 kb/s. The rate can vary significantly with the number of users. For GSM operators, the first stop along the upgrade path will be GPRS. Like the CDMA 1XRTT upgrade, GPRS does not require new base stations. Once GPRS has been implemented, an operator will be able to provide an advertised data rate of 115 kb/s. Current test users are experiencing rates of approximately 20 to 50 kb/s, with the expectation that these rates will be improved. Some US-TDMA operators may even consider installing new base stations and moving directly to EDGE. To the best of our knowledge, North American carriers aiming to move to ‘true 3G’ (1X-EV DO, 1X-EV DX/3X, EDGE, w-CDMA) will need to deploy new base stations. As with European carriers (see ‘Facing up to the 3G/RF challenge’ of last issue STAY CONNECTED), this will pose a number of RF challenges to the North American carrier. Unlike European spectrum authorities, there has been no firm commitment by the US Federal Communications Commission to allocate spectrum for 3G deployment to-date. Many options are currently being considered—to use the European Digital Communication System (DCS) frequency range currently used by the US Military; to
use the 2.5 to 2.7 GHz range; or to use the 700 MHz UHF range. Some carriers have speculated that there might be no need to allocate a distinct 3G spectrum at all, and that there is adequate capacity in the existing Personal Communications Service (PCS) range. New challenges—RFS solutions Regardless of the ultimate outcome of the 3G spectrum debate, it is clearly obvious that North American carriers will need many new sites in the future to accommodate the demand for capacity and high speed data. This will create a number of challenges —challenges RFS is currently developing technology and services to help meet. There will be more co-location, driven by environmental and site-cost considerations. With co-location and increased numbers of sites that are closer together, we can expect band version of the RFS OPTIMIZER solution, specifically to meet this North America demand. Finally, co-location will create an increased demand for specialized/customized filter. RFS has long provided North American ‘A’ and ‘B’ cellular operators with purposebuilt filters to help reject the other carrier’s signal. RFS’s expertise and experience in this area will help meet the increased demand for filter technology in this ‘new age’ high-density base station scenario. Factors for success For any operator looking to move along the 2.5/3G upgrade path, there are several factors that will provide for success. Operators will need to market advanced features and services to consumers, to assure that they understand the value of these new systems. CELLULAR DIRECTIONS 9 an increase in demand for interference management. An important tool in minimising this interference will be the RFS OPTIMIZER technology, which uses variable electrical tilt (VET) to precisely trim the antenna coverage area. Increased co-location will also drive an increased need for dual, and ultimately triple band antenna technologies on some sites. Later this year, RFS will launch a dual Table 1: North America’s Upgrade Path to 3G 2000 2001/2002 2002/2003 2003/2005 CDMA IS-95A 1XRTT 1X-EV DO 1X-EV DV/3X 14.4 kb/s 144 kb/s 2.4 Mb/s 3 to 5 Mb/s GSM GSM GPRS EDGE W-CDMA 9.6 kb/s 115 kb/s 384 kb/s 2 Mb/s Operators will also need to ensure that they are at the correct point on the development time line ‘map’, and that compatible terminals are ready for market when required. If they move down the technology road too rapidly they may find that consumers are not ready for these advanced services. If they move too slowly, they risk being seen by consumers as being behind their competitors. Key wireless OEMs will continue to provide options that offer flexible and cost effective solutions. Both operators and OEMs will face important RF challenges on this path to 3G—RFS will be there to work through these challenges with its customers and help bring these exciting new applications to the world. TDMA CDPD — EDGE W-CDMA 19.2 kb/s — 384 kb/s 2 Mb/s
Page 1 and 2: The Radio Frequency Systems Bulleti
Page 3 and 4: IMPRINT Happy 3rd anniversary STAY
Page 5 and 6: RFS dual band & broadband 3G antenn
Page 7: New office heralds South African bu
Page 11 and 12: Photos by Sergei Karpuchin. © Reut
Page 13 and 14: RFS tools— introducing X-tilt and
Page 15 and 16: Performance milestones RF cable tec
Page 17 and 18: operational windspeed for this size
Page 19 and 20: It’s show time! Radio Frequency S

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