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3G is the term used to describe next generation mobile services that provide better quality voice and high-speed Internet and multimedia services. The ITU requires that IMT-2000 (3G) networks, among other capabilities, deliver improved system capacity and spectrum efficiency over the 2G systems and support data services at minimum transmission rates of 144 kbps in mobile (outdoor) and 2 Mbps in fixed (indoor) environments.

Presently, there are around 50 mn 3G customers worldwide of which WCDMA contribution is around 33 mn whereas EV-DO is around 17 mn.  

India is focusing on both technologies EV-DO and 3GSM (W-CDMA) and is planning for a simultaneous release of spectrum in the 2 GHz and 800 MHz frequency bands.   

• CDMA2000: CDMA2000 is one of the five standards. It is also known by its ITU name IMT-CDMA Multi Carrier. CDMA2000 represents a family of 3G and next-generation standards with advanced voice, data and multimedia capabilities to meet the rapidly evolving demand for wireless and converged communication services. The underlying principle of the CDMA2000 evolution path is backward and forward compatibility allowing operators to seamlessly and cost-effectively upgrade their existing networks.

• CDMA2000 1xEV-DO: CDMA2000 1xEV-DO (evolution-data optimized) introduces a new air interface with technical features that are specifically designed for all-data network. CDMA2000 1xEV-DO has been approved as an IMT-2000 standard. In order to take full advantage of an all-IP network and an air interface that has been optimized for data, CDMA2000 1xEV-DO does require a multi-mode device to be fully backward compatible. 

• CDMA2000 1xEV-DO Release 0: CDMA2000 1xEV-DO Release 0 provides a peak data rate of 2.4 Mbps in the forward link and 153 kbps in the reverse link in a 1.25 MHz CDMA carrier. With average throughput of 400-800 Kbps in the forward link, it delivers the highest data rates of any wide area network wireless technology deployed today. It leverages the existing suite of Internet Protocols (IP). Hence, it supports all popular operating systems and software applications. It offers an “always on” user experience and supports advanced data applications such as MP3 transfers and video conferencing, TV broadcasts, video and audio downloads.

• CDMA2000 1xEV-DO Rev A: CDMA2000 1xEV-DO Rev A represents a major step towards converged communication networks and ubiquitous delivery of voice and data services across fixed and wireless networks. Revision A is an all IP-based air interface and integrates voice (VoIP), high-speed packet data and enhanced multimedia capabilities. It is an evolution of CDMA2000 1xEV-DO Release 0, and it adds higher data rates, higher system capacity and improved QoS support for low-latency packet applications. It also supports enhanced multicast capabilities and helps in delivering high-quality bandwidth intensive video and audio applications to a large base in a cost effective manner.
      Rev A delivers a peak data rate of 1.8 Mbps on the reverse link and 3.1 Mbps on the forward link. Not only it supports higher system capacity but improved quality of service. Revision A is backwards compatible with 1xEV-DO Release 0 and allows operators seamless migration while preserving their investments in the CDMA2000 systems. Revision A services will be commercial in early 2007 with mass market deployments in 2007 and 2008.

• CDMA2000 1xEV-DO Revision B: The Revision B standard will be published in the Ist quarter of 2006. Revision B introduces a 64-QAM-modulation scheme and will deliver peak rates of 73.5 Mbps in the forward link and 27 Mbps in the reverse link through the aggregation of 15, 1.25 MHz carriers within 20 MHz of bandwidth. In addition to supporting mobile broadband data and OFDM-based multicasting, the lower latency characteristics of Revision B will improve the performance of delay-sensitive applications such as VoIP, push-to-talk over cellular, video telephony, concurrent voice and multimedia and massive multiplayer online gaming. Revision B is planned to be commercially available in 2008.

• HSDPA: HSDPA is typically a software upgrade to W-CDMA network thereby enabling operators to roll out this high-speed technology rapidly and cost effectively. HSDPA is high-speed mobile broadband, enabling a wide variety of high bandwidth multimedia services including high quality streaming video, fast downloads of high resolution images and large files, interactive e-mails and gaming, and telematics. It doubles network capacity, while making transmission of everything from voice calls to video pictures more efficient, boosting download speeds as much as fivefold.

Compared with WCDMA, HSDPA increases throughput up to 14.4 Mbps, reduces latency, and increases data capacity up to 5x in dense urban environments. One can get speeds up to 14.4 Kbps on downlink-shared channel on the same carrier and can be deployed in both FDD and TDD modes.            

More than 80 WCDMA networks have been deployed worldwide in 37 countries.    

Cingular Wireless has become the first mobile operator in the world to launch an extensive HSDPA service and is offering laptop users wireless access to the Internet initially at speeds averaging between 400 and 700 Kbps in 16 cities. On the other hand, Manx Telecom, owned by O2 has launched Europe's first service on the Isle of Man.    

The GSM Association (GSMA), in an initiative led by TeliaSonera has begun interoperability trials on three continents to ensure that mobile users will be able to share video across networks. The video share trials are due to be completed in the first half of 2006 and GSMA has brought together equipment makers and handset vendors for this trial.

• Wi-Max (Worldwide Interoperability for Microwave Access): This is the trade name given to a group of wireless technologies that emerged from IEEE 802.16 WirelessMAN (Metropolitan Area Network) standards. Although Wi-Max is only a few years old, 802-16 has been there from a long time, first with the adoption of 802.16 standard  (10-66 GHz) and then with 802.16a (2-11 Ghz).

The Wi-Max umbrella currently includes 802.16-2004 and 802.16e. 802.16-2004 utilizes Orthogonal Frequency Division Multiplexing (OFDM), to serve multiple users in a time division fashion in a sort of a round robin technique, but done extremely quickly so that users have the perception that that they are always transmitting or receiving. 802.16e utilizes Orthogonal Frequency Division Multiple Access (OFDMA) and can serve multiple users simultaneously by allocating sets of tones to each user.

802.16-2004 is a fixed wireless access technology designed to serve as a wireless DSL replacement. Wi-Max can provide broadband access in remote and developing parts of the world where basic voice or broadband access using fixed line service is not economically feasible. Additionally, Wi-Max can be useful to provide backhaul in cellular networks and also can be used for enhancing the reach of public Wi-Fi hot spots by increasing the throughput in the backhaul network.

802.16e is an unpublished standard that is intended to offer a key feature that 802.16-2004 lacks – portability and eventually fullscale mobility. This standard requires a new hardware and software solution since it is not backward compatible with 802.16-2004

Wireless Broadband
WiBro (Wireless Broadband) is a South Korean initiative and will be included in 16e umbrella, thus making it another potential Wi-Max profile. It is a TDD-based system that operates in a 9 MHz radio channel at 2.3 GHz with OFDMA as its access technology. It also supports users traveling at speeds of up to 120 Km/hr with peak user data rates of 3 Mbps in the downlink (uplink = 1 Mbps) and 18 Mbps of peak sector throughput in the downlink (uplink = 6 Mbps)    

Today, there are approximately 300 odd companies like Alcatel, Ericsson, Lucent, Motorola, Nortel, and Siemens, to name a few. On the chipset front, Intel, Fujitsu and many others are joining to make the proposition look attractive.

Wi-Max is a credible solution to a number of solutions that have plagued the fixed wireless industry ie the lack of an open standard and absence of major silicon vendors and equipment suppliers. Once Wi-Max certified equipment is available from a number of suppliers, increased competition along with increased volume shipment will result in attractive price points.

There are several market opportunities for Wi-Max, some more viable than others. Wi-Max opportunities are in developing, developed, wireless backhaul in cellular networks, and wireless backhaul in Wi-Fi network. 

Developing and Underserved Markets
Several regions of the world, copper wire to the home or enterprise is still not being deployed. In these circumstances, a fixed wireless offering based on open standard may make more economic sense than deploying copper wire. First it can be deployed faster and also provide manageable speeds.

DSL and cable modem replacement and extension
There are some markets and regions where the economics of running cable or putting in DSLAM does not make sense and in these cases, a fixed broadband wireless access technology might be more appropriate. We have already seen WISPs (Wireless Internet Service Providers) operating in niche areas.

Wireless backhaul in a cellular network
In the past and till date, microwave radios have been used by the cellular industry to provide backhaul, or transport, of voice and data traffic from outlying cell sites to the operator's core network. The service providers' decision to opt for wireless backhaul will be based on availability of sufficient spectrum. And this will increase further with 3G deployments by operators.

Wireless backhaul in a Wi-Fi network
A more likely scenario is that Wi-max will be used to provide backhaul in a Wi-Fi network. Another limitation with public Wi-Fi is the cost and inconvenience associated with the wire line backhaul. If nothing else, the network throughput could be dramatically increased for far less cost in comparison to copper or fiber.

Wi-Max Spectrum
Wi-Max covers a range of spectrum below 11 GHz. The available spectrum falls into two distinct categories-unlicensed and licensed. In most markets, the unlicensed spectrum that could be used for Wi-Max is 2.4 GHz and 5.8 GHz. Since it is unlicensed, the entry barrier is low. But unlicensed band has its own disadvantages like interference, increased competition, and limited power.  Since unlicensed can be used by a lot of operators, there is a high probability of spectrum. And majority of telcos would not be comfortable starting service using unlicensed spectrum band.

On the other hand, licensed spectrum comes at a price and is free from interference. The unlicensed spectrum is found at 700 MHz, 2.3 GHz, 2.5 GHz, and 3.5 GHz.      

Beginning of this year, Wi-Max Forum announced the first fixed wireless broadband network products to achieve the designation of WiMax Forum Certified. The first companies and products to complete certification and interoperability testing including Aperto Networks' PacketMax 5,000 base station, Redline Communcations' RedMAX AN-100U base station, Sequans Communications' SQN2010 SoC base station solution, and Wavesat's miniMAX customer premise equipment solution.

Pravin Prashant
pravinp@cybermedia.co.in