3.4 Competing Technologies

Since the very high speed running of wireless communication technology, it's not wise to concentrate only one standard or technology. A good advice is to look around as many as relevant and comparable technologies with worldwide view. Currently, a lot of interesting technologies such as HiperMAN, UMTS related, HSPA, CDMA2000 and so on are developing fleetly at different situation and environment. Even though I believe within a certain period in future, WiMAX will be the most promising standard and technology to be developed for wireless access, we also need to know some other competing and great technologies which may be exceeding than WiMAX in some special aspects. In this section, such these technologies will be introduced briefly and concentration will be their comparison.

HiperMAN

HiperMAN stands for High Performance Radio Metropolitan Area Network and is a standard created by the European Telecommunications Standards Institute (ETSI) Broadband Radio Access Networks (BRAN) group to provide a wireless network communication in the 2 - 11 GHz bands across Europe and other countries which follow the ETSI standard. Actually, The ETSI HiperMAN is commonly thought to be the equivalent of IEEE 802.16 (or WiMAX). HiperMAN is a European alternative to WiMAX (or the IEEE 802.16 standard) and the Korean technology WiBro. Wibro will be introduced later.

HiperMAN is aiming principally for providing broadband Wireless DSL, while covering a large geographic area. The standardization focuses on broadband solutions optimized for access in frequency bands below 11 GHz (mainly in the 3.5 GHz band). HiperMAN is optimised for packet switched networks, and supports fixed and nomadic applications, primarily in the residential and small business user environments. Like Fixed WiMAX, HiperMAN is an interoperable FBWA (Fixed Broadband Wireless Access) system operating at radio frequencies 2 - 11 GHz. HiperMAN standard took the IEEE 802.16 and the amendment of IEEE 802.16a PHY as a baseline, thus, both OFDM-based PHY layers shall comply with each other and a global OFDM system could emerge. HiperMAN has been designed to fulfill today's most promising challenges[1]: Nonprofessional installation of terminals to significantly cut the deployment cost, is enabled due to non-line-of sight operation capability; rapidly scalable infrastructure deployment will decrease time to market for new broadband services which will be crucial for the success of new operators; efficient spectrum usage enables operators to offer services requiring high peak bit rate; modular cost-effective growth is possible becouse the main cost of radio access lies in the equipment itself; radio offers the possibility of selective access, easier bridging of distances to customers than fiber or copper; QoS support for packet-based services is provided by the system. Also, HiperMAN enables both PTMP and Mesh network configurations. HiperMAN also supports both FDD and TDD frequency allocations and H-FDD terminals. All this is achieved with a minimum number of options to simplify implementation and interoperability [2].

UMTS

UMTS is the short term of Universal Mobile Telecommunication System, which is one of the third-generation (3G) cell phone technologies. Currently, the most common form of UMTS uses W-CDMA as the underlying air interface. It is standardized by the 3GPP (The 3rd Generation Partnership Project), and is the European answer to the ITU IMT-2000 requirements for 3G cellular radio system. UMTS supports up to 14 Mbit/s data transfer rates in theory , although at the moment users in deployed networks can expect a transfer rate of up to 384 Kbit/s for R99 handsets, and 7.2 Mbit/s for HSDPA handsets in the downlink connection. This is still much greater than the 9.6 kbit/s of a single GSM error-corrected circuit switched data channel or multiple 9.6 kbit/s channels in HSCSD (14.4 kbit/s for CDMAOne), and—in competition to other network technologies such as CDMA2000, PHS or WLAN—offers access to the World Wide Web and other data services on mobile devices. This means UMTS is the more advanced standard than GSM in this family. Since 2006, UMTS networks in many countries have been or are in the process of being upgraded with HSDPA (High Speed Downlink Packet Access), sometimes known as 3.5G. Work is also progressing on improving the uplink transfer speed with the HSUPA (High Speed Uplink Packet Access). Moreover, in long term, the 3GPP Long Term Evolution project plans to move UMTS to 4G speeds of 100Mbit.s down and 50 Mbit/s up, suing a next generation air interface technology based on OFDM. In this degree, UMTS is a typical competitor of WiMAX. UMTS supports mobile video conferencing as well, although experience in Japan and elsewhere has shown that user demand for video calls is not very high.

Technologically, UMTS combines the W-CDMA, TD-CDMA (or TD-SCDMA) air interface, GSM's Mobile application part (MAP) core, and the GSM family of speed codecs [3]. It uses a pair of 5 MHz channels and in contrast, CDMA2000 system uses one or more artitrary 1.25 MHz channels for each direction of communication. The specific frequency bands originally defined by the UMTS standard are 1.885–2.025 GHz for the uplink and 2.11–2.2 GHz for the downlink. But in some other countries, the frequency bands are different a little bit such as in U.S., 1.71-1.755 GHz and 2.11-2.155 GHz will be used instead. The 3G handsets such as phones, PDA, smartphones and external modems are the main supporters and users of UMTS standards. This kind of phones are highly portable and interoperable. The major technique we may concern is HSPA in UMTS family. At this moment, the main problem is the available frequency bands for UMTS and compatibility. The comparison with WiMAX of UMTS is basically on the internet access side. HSPA will be discussed to compare with Mobile WiMAX as below paragraphs.

HSPA

The 3rd Generation Partnership Project (3GPP) is a collaboration that brings together a number of telecommunications standards bodies. The USA, Europe, Japan, SouthKorea and China jointly formed the 3GPP. At present, it has more than 400 membercompanies and institutions. The 3GPP defines GSM and WCDMA specifications fora complete mobile system, including terminal aspects, radio access networks, corenetworks, and parts of the service network. Standardization bodies in each worldregion have a mandate to take the output from the 3GPP and publish it in their regionas formal standards.

Obviously, HSPA involves HSUPA and HSDPA existing in the family provide increased performance by using improved modulation schemes and by refining the protocols by which handsets and base stations communicate. These improvements lead to a better utilization of the existing radio bandwidth provided by UMTS. The number of commercial 3.5G networks--also known as High-Speed Downlink Packet Access, or HSDPA, networks--launched worldwide grew by 69 percent in 2007. There are now 174 commercial HSDPA networks in 76 countries. An additional 38 networks are committed to rollouts, which will bump the total to 211 HSDPA networks in 90 countries. Commercial HSDPA networks are widely available in Western Europe (61 networks), Southeast Asia (35), Eastern Europe (34), the Middle East and Africa (20), and the Americas and the Caribbean (16). Almost two-thirds (62 percent) of existing commercial HSDPA networks support downlink speeds of 3.6 Mbit/s or more, while more than a fifth (21 percent) support the peak downlink speed of 7.2 Mbit/s [4]. Many HSPA rollouts can be achieved by a software upgrade to existing 3G networks, giving 3.5G a headstart over WiMax, which requires dedicated network infrastructure.

Similarly, HSPA and Mobile WiMAX technologies have been designed for high-speed packet-data services. They feature similar technology enablers, including dynamic scheduling, link adaptation, H-ARQ with soft combining, multiple-level QoS, and advanced antenna systems. Notwithstanding, their performance differs due to differences in the physical layer signal format, duplex scheme, handover mechanism, and operating frequency bands [5]. The technical comparison of HSPA and Mobile WiMAX is shown in the table [5] below:

If we look at the information at performance till 2008, we can obtain the conclusion that HSPA and Mobile WiMAX is comparable in many areas. The key differences in areas such as duplex mode (FDD versus TDD), frequency bands, multiple access technology,and control channel design give rise to differences in uplink bit rates and coverage. While the peak data rates, spectral efficiency and network architecture of HSPAEvolution and Mobile WiMAX are similar, HSPA offers better coverage. In short, Mobile WiMAX does not offer any technology advantage over HSPA [5]. So that means HSPA is on the preponderant situation refering to Mobile WiMAX and it's a very strong competitor to WiMAX especially in developed and mature markets!

CDMA2000

CDMA2000 is considered a 2.5G technology in 1xRTT and a 3G technology in EVDO. It is a hybrid 2.5G/3G technology of mobile telecommunications standards which use CDMA, a multiple access scheme for digital radio, to send voice, media, data, and signalling data between mobile phones and cell sites or base stations. CDMA is Code Division Multiple Access for short. and it permits many simultaneous transmitters on the same frequency channel, unlike TDMA, used in GSM and FDMA used in AMPS. Since more phones can be served by fewer cell sites, CDMA based standards have a significant economic advantage over TDMA or FDMA based standards. CDMA will offer high capacity channels. The CDMA2000 standards CDMA2000 1xRTT, CDMA2000 EV-DO, and CDMA2000 EV-DV are approved radio interfaces for the ITU's IMT-2000 standard and a direct successor to 2G CDMA, IS-95 (cdmaOne). CDMA2000 is standardized by 3GPP2. Some details about CDMA2000 1xRTT, CDMA2000 EV-DO, and CDMA2000 EV-DV can be refered to [6].

CDMA2000 is an incompatible competitor of the other major 3G standard UMTS. It is defined to operate at 450MHz, 700MHz, 800MHz, 900MHz, 1700MHz, 1800MHz, 1900MHz and 2100MHz. So if we look at the CDMA (3GPP2) family, Evolution-Data Optimized (EV-DO) and Ultra Mobile Broadband (UMB) are more competitive because EV-DO is a telecommunications standard for wireless transmission of data through radio signals typically for broadband internet access and it was designed as an evolution of the CDMA2000 standard. And UMB is for the project within 3GPP2 to improve the CDMA2000 mobile phone standard for next generation applications and requirements. UMB also was seen to be as pre-4G. To provide compatibility with the systems it replaces, UMB supports handoffs with other technologies including existing CDMA2000 1X and 1xEV-DO systems. However, according to the technology market research firm ABI Research, Ultra-Mobile Broadband might be "dead on arrival". No carrier has announced plans to adopt UMB, and most CDMA carriers in Australia, USA, China, Japan and Korea have already announced plans to adopt HSPA or LTE.

Actually, the CDMA2000 migration path maximizes performance while minimizing costs by sustaining an evolutionary paththat is based on backwards compatibility. This has provided CDMA2000 operators with significant time-to-marketand economic advantages; CDMA2000 technologies provide industry-leading network capacities, low latencies and RF propagation characteristicsenabling operators to offer high-quality voice and robust broadband and multimedia applications very cost effectivelyin any topology or location; CDMA2000 will remain a leading "core" platform to deliver next-generation mobile broadband services, and will enableoperators to integrate their existing CDMA2000 networks with wider-bandwidth OFDM-based radio technologies such as LTE, UMBTM, WiMAX, DVB-H, MFLO, T/S-DMB, ISDB-T and Wi-Fi (802.11n) to support high-quality multimediaservices in the future. From the research of CDMA Development Group [7], it shows that CDMA2000 continues to strengthen its market position as the leading 3G technology worldwide, providing advanced voice and broadband mobile services across diverse markets, and as an integral component in the next generation of converged mobile broadband services. Some data from "CDG" also show that CDMA2000 is the most widely used 3G solution worldwide[7].

WiBro

WiBro is Wireless Broadband, which is a wireless broadband internet technology being developed in the South Korean. Root from IEEE 802.16e, WiBro is the South Korean service name of Mobile WiMAX international standard.

WiBro adapts TDD for duplexing, OFDMA for multiple access and 8.75 MHz as a channel bandwidth. WiBro was devised to overcome the data rate limitation of mobile phones (for example CDMA 1x) and to add mobility to broadband Internet access (for example ADSL or Wireless LAN). WiBro base stations will offer an aggregate data throughput of 30 to 50 Mbit/s and cover a radius of 1-5 km allowing for the use of portable internet usage. In detail, it will provide mobility for moving devices up to 120 km/h (74.5 miles/h) compared to Wireless LAN having mobility up to walking speed and Mobile Phone having mobility up to 250 km/h. Some Telcos in many countries are trying to commercialize this Mobile WiMAX (or WiBro). For example, TI (Italia), TVA (Brazil), Omnivision (Venezuela), PORTUS (Croatia), and Arialink (Michigan) will provide commercial service after test service around 2006-2007. While WiBro is quite exacting in its requirements from spectrum use to equipment design, WiMAX leaves much of this up to the equipment provider while providing enough detail to ensure interoperability between designs. So WiBro may be considered to be renamed of Mobile WiMAX by the South Korean telecoms industry. In South Korean, SK Telecom and Hanaro Telecom have announced a partnership to roll out WiBro nationwide in Korea, excluding Seoul and six provincial cities. In 2004, Intel and LG executives agreed to ensure compatibility between WiBro and WiMAX technology; Samsung signed a deal with Sprint Nextel to provide equipment for WiBro in Sept. 2005; KT Corporation launched commercial WiBro service in mid-2006 and Sprint, BT, KDDI and TVA have or are trialing WiBro; on 2007, KT launched WiBro coverage for all areas of Seoul including all subway lines.

Comparably, WiBro and HSPA services are different technological platforms but both provide voce/video telephone calls and data transmission services at the same time, which makes it inevitable that they are at war for market dominance. Of course, WiMAX also must be involved into this war because these three competing technologies and standards are comparable. They are leading to different types and areas of markets. And the competition will continue in the future.

[1] Christian Hoymann, Markus P¨uttner, Ingo Forkel, "The HiperMAN Standard - a Performance Analysis", RWTH Aachen University, Germany.
[2] http://en.wikipedia.org/wiki/HIPERMAN
[3] http://en.wikipedia.org/wiki/UMTS
[4] http://en.wikipedia.org/wiki/High-Speed_Packet_Access
[5] "Technical Overview and performance of HSPA and Mobile WiMAX", White Paper of ERICSSON, Sept. 2007.
[6] Vieri Vanghi, Aleksandar Damnjanovic, Branimir Vojcic, "The cdma2000 System for Mobile Communications: 3G Wireless Evolution", Prentice Hall Communications Engineering and Emerging Technologies Series, Prentice Hall, 2004.
[7] http://www.cdg.org/