3.3 Mobile WiMAX

What is Mobile WiMAX? Is there any difference between Mobile WiMAX and IEEE 802.16? How we distinguish Mobile WiMAX and Fixed WiMAX? In this section, basic technology analysis about Mobile WiMAX, products and application, economic perspective, potential, and even challenges will be summarize. I will also mention its situation in developing countries.

Technology and concept domain

In 2005, the standard was amended (IEEE 802.16e-2005 or 802.16e) adding support for data mobility. As mentioned in previous chapter and section, 802.16e basically focus on mobile application for WiMAX technology. It improves on the modulation schemes used in original (Fixed) WiMAX standard by introducing SOFDMA (scalable orthogonal frequency-division multiple access). The system profile in IEEE 802.16e-2005 is not backward compatible with the fixed WiMAX system profile.

Compare with Fixed WiMAX, nowadays, WiMAX is also called Mobile WiMAX as it can serve all usage models from fixed to mobile with the same intrastructure. Actually, without mobility, WiMAX will be suffered because its advantages are buried. Based on the IEEE 802.16e-2005 standard, Mobile WiMAX offers fixed nomadic, portable and mobile capabilities; and Mobile WiMAX doesn't reply on line-of-sight transmissions in lower frequency bands (2 to 11 GHz); it provides enhanced performance, even in fixed and nomadic environments and currently uses TDD; system bandwidth is scalable to adapt to capacity and coverage needs [1]. As I said before, in phisical layer, 802.16e uses SOFDMA to carry data, supporting channel bandwidths of between 1.25 MHz and 20 MHz, with up to 2048 sub-carriers. It supports adaptive modulation and coding, so that in conditions of good signal, a highly efficient 64 QAM coding scheme is used, whereas where the signal is poorer, a more robust BPSK coding mechanism is used. In intermediate conditions, 16 QAM and QPSK can also be employed. Other PHY features include support for Multiple-in Multiple-out (MIMO) antennas in order to provide good NLOS (Non-line-of-sight) characteristics (or higher bandwidth) and Hybrid automatic repeat request (HARQ) for good error correction performance. At the same time, in media access control layer (MAC), it describes a number of Convergence Sublayers which describe how wireline technologies such as Ethernet, ATM and IP are encapsulated on the air interface, and how data is classified, etc. It also describes how secure communications are delivered, by using secure key exchange during authentication, and encryption using AES or DES during data transfer. Further features of the MAC layer include power saving mechanisms and handover mechanisms. QoS in 802.16e is supported by allocating each connection between the SS and the BS (called a service flow in 802.16 terminology) to a specific QoS class. In 802.16e, there are 5 QoS classes which are: Unsolicited Grant Service, Extended Real-time Polling Service, Real-time Polling Service, Non-real-time Polling Service and Best Effort.

Standard, application and market domain

According to products and application, designed from the beginning to connect to the IP network, mobile WiMAX offers low latency and high QoS. It will have no difficulty accessing IP multimedia data or implement technologies such as VoIP. This is the basic argument driving the mobile WiMAX campaign for market acceptance. In the ever widening world of wireless technologies, mobile WiMAX is aimed at a very lucrative market: the delivery of high-data bandwidth digital data streaming off the IP network. In other words, the much-talked-about delivery of mobile services. Mobile WiMAX can be embedded on any number of personal devices such as PDAs, notebook PCs, game consoles, iPods, MP3 players, and cellular phones. As such, its potential to compete with cellular technology is obvious, particularly for broadband, data-centric applications. But mobile WiMAX may also co-exist with cellular technology. WiMAX is not optimized to carry circuit-switched voice traffic. From the WiMAX perspective, voice is a far more appropriate application for cellular technology. The problem with that scenario from the cellular perspective is that the expected growth in mobile revenue is in the data segment. Between 2004 and 2008, a 20% CAGR is forecast for mobile data while revenue for mobile voice traffic is actually expected to drop by a few percent over the same period. Voice revenues will still be almost double data in 2008 but the trend is clear [2]. Mobile WiMAX performance is typically compared to 3G technologies such as EVDO (Evolution Data Optimized) and HSDPA (High Speed Downlink Packet Access), and HSUPA. Depending on system configuration, mobile WiMAX has a clear performance edge. The typical and concrete comparison between Mobile WiMAX and HSDPA, etc. will be discussed in the following section.

For the economic phase, the case for mobile WiMAX being a cost effective technology is fundamentally one of standards and interoperability. Equipment must conform to the IEEE 802.16e-2005 and ETSI HiperMAN 1.3.2 standards but it is well known that meeting those standards does not necessarily translate into interoperability between products from different manufacturers [2]. For mobile WiMAX, the WiMAX Forum will reprise its interoperability certification program for fixed WiMAX. Interoperability allows system operators to shop around for base stations and end user equipment as well as decide when to upgrade. One of the more interesting synergies between technologies brings together mobile WiMAX and Wi-Fi capability in a single chipset. This perspective is not as popular with the Wi-Fi camp as it is with the WiMAX proponents. But the combination of the two technologies into a single chipset would certainly bring down the cost of end-user equipment. Perhaps the biggest cost advantage of WiMAX compared to cellular comes not out of standards or higher levels of integration but royalty payments. Royalties paid by manufacturers of WCDMA phones, for example, average between 10% and 15% for the average selling price of the phone. This is big difference from the 2% to 5% royalty charges in the rest of the telecommunications industry. Significantly, the WiMAX Forum is clearly looking for royalty solutions that are far less onerous [2].

For wireless fields, no standard can monopolize the market and technology. Any operator considering mobile WiMAX should take into consideration the following challenges account [3]:

1) There are currently more than 32 million HSPA connections worldwide, with nearly 467 HSPA mobile handsets offering 4Mbps in the downlink, which is comparable to Mobile WiMAX.
2) 3G LTE is expected to be a fully ratified standard by the end of this year, with trials occurring in 2009 and deployments in late 2009 or 2010 offering mobile data rates of up to 170Mbps (2×2 MIMO; 2.6GHz; 20MHz).
3) QUALCOMM’s Gobi technology which supports GSM, GPRS, EDGE, HSPA, EV-DO Rev A will be integrated into laptops this year, which either have been certified, or will be certified with operators such as T-Mobile, Telefonica, Verizon Wireless and Vodafone. Tier 1 laptop vendors such as HP and Dell are supporting this.
4) Nearly 97 percent of laptops are shipped with integrated Wi-Fi technology today.
5) The number of dual-mode Wi-Fi/Cellular mobile phones is on the rise with newer models emerging at lower costs with better battery life.
6) Recently Alcatel-Lucent, Ericsson, NEC, NextWave Wireless, Nokia, Nokia Siemens Networks and Sony Ericsson invited all interested parties to join an initiative to keep royalty levels for essential LTE patents in mobile devices below 10 percent of the retail price, with the maximum royalty in LTE-enabled notebooks restricted to under $10. It is still unclear if members of the WiMAX Forum have reached an agreement pertaining to the intellectual property rights they possess for Mobile WiMAX.

For these challenges, I totally agree the author in [3] so that WiMAX Forum and IEEE 802.16 Task Group should try to push there work to spread WiMAX more widely and agree more acceptably price in Market besides its high quality in technology domain.

We can not say Mobile WiMAX must be successful in mature mobile broadband markets, but it will have a nice future in Brazil, Russia, India and China, etc., so-called BRIC countries, especially in India according to an analysis made by Cantab Wireless who believe that while Mobile WiMAX is a powerful technology and it cannot fulfil all the expectations placed upon it. Competing against 3G cellular networks in mature telecommunications markets, Mobile WiMAX is considered as the adversary. It's a big challenge for Mobile WiMAX. Hence, the research firm forecast that Mobile WiMAX will not be able to gain a significant foothold in developed markets. Actually, I do not make the agreement about the result from these research firms, but if we look at the developing markets, the situation is not quite so depressing for Mobile WiMAX which is the common attitude of us. Typically, the lack of cellular broadband services in a country implies there is no market for those services to date. Thus, Mobile WiMAX has to make its break in countries which do not include mobile broadband yet but which are developing fast. The BRIC countries match this description well.

Totally speaking, Mobile WiMAX is a well-perspective technology with high quality and perfect service as mobile wireless standard. And Why Mobile WiMAX will be chosen by such a lot of organizations and corporations will be composed in other degree after comparing with other competing standards in the latter chapter.


[1] WiMAX Questions & Answers, WiMAX Forum, Jan. 2008.
[2] Jack Shandle, What is Mobile WiMAX?,
[3] Abu Saeed Khan, Mobile WiMAX - The End is Nigh, 12th Executive Course on Telecom Reform, 2008. http://lirneasia.net/2008/07/mobile-wimax-the-end-is-nigh.