Thursday, July 16, 2009

IEEE Mobile WiMAX Symposium – Part I

The IEEE Mobile WiMAX Symposium, which I attended for the first time last week, is a small (~50 people) workshop-style meeting that provides a great opportunity to interact with leaders in the field of 4G technology. Keynote presentations provided an overview of technology directions and vision, while individual paper sessions dug deep into details of theory and applications.

Opening Keynote

Intel Fellow and Mobility Group CTO Dr. Siavash M. Alamouti opened the symposium with his presentation on "Mobile WiMAX, Roadmap for the Mobile Internet Revolution". Dr. Alamouti began with an expansive vision of the impact of the internet from the Organisation for Economic Co-operation and Development (OECD). While we tend to focus on how 3G and 4G technologies will create a ubiquitous mobile internet for our laptop PCs and smartphones, the OECD takes a broader view while raising some societal concerns that I also touched on in my last post here (CiscoLive! and the impact of video).

Beyond the current Internet, a set of new technologies, such as radio frequency identification (RFID) and location-based technologies, are predicted to enable new innovative applications and cause the network to evolve into an "Internet of Things". In the longer term, small wireless sensor devices embedded in objects, equipment and facilities are likely to be integrated with the Internet through wireless networks that will enable interconnectivity anywhere and at anytime. The future uses and capacities of technologies that bridge the physical and virtual worlds are expected both to bring economic benefits and raise new societal challenges.
-OECD Policy Brief, June 2008

The "internet of things" is a subject that I will be writing more about, and it was somewhat of a recurring theme in other presentations at the Symposium as well.

3G/4G Wireless Business Models

Dr. Alamouti then focused on issues in wireless operator business models that, in his opinion, are inhibiting the growth of the mobile internet.

"Why is the cellular industry not motivated to deliver mobile internet?"

One of his central arguments was that operators have been slow to deliver the mobile Internet because the relative cost of delivering data is much higher than for voice, while the current revenues (and ARPUs) are much lower. I see the situation as just the opposite.

Almost all growth is coming from data, which should be plenty of incentive for providers to invest more in this area. While overall adoption of 3G services is currently only around 10%, this is by far the highest growth area in the U.S. cellular business, and the revenue differential is not as large here as in other regions of the world.

Emerging markets pull down the overall average because of the necessity to provide very low cost handsets and services.

More than forty percent of cell phone users have expressed a desire to purchase a smartphone as their next handset. Data ARPU is growing rapidly, while voice ARPU has been flat or declined for most operators in the last two years.

Looking at the leading example of this high growth area; AT&T has gained tremendously from the iPhone, adding 1.6M new users in Q1-2009 alone. As a result, in Q1-2009 AT&T had data revenue of $3.2B (+38.6% Y-Y), contributing to overall wireless revenue in the quarter of $11.7B (+9.6% Y-Y). Data revenue accounted for more than 86% of the overall growth from Q1-2008 to Q1-2009.

All these points argue for accelerating deployment of lower cost/bit flat IP-based 4G networks. (I cover this topic in more detail in my report on
The Emerging 4G Wireless Landscape in the U.S.). However, different business models are required as well. Dr. Alamouti correctly pointed out that

"Consumers do NOT understand the cellular data usage model"
In my opinion, capped data plans that penalize so-called "abusive" data consumption should have gone out with AOL dial-up. Operators need to make their plans easy to use and affordable. For cellular voice adoption the technical issues have been coverage and reliability. For data plan adoption, the new issues are capacity and speed.

Lack of capacity has become the cellular industry's dirty little secret. As a result, one of the growth areas in the wireless industry now is the development of policy enforcement and traffic management tools to help operators avoid having their 3G networks crawl to a stop. (See Webinar: The Multi-faceted Role of Policy: PCRF and the Personalization Imperative, as an example).

Intel's "Wireless Silicon" Roadmap

The Atom™ microprocessor was described as a device that "will revolutionize the PC industry to mass market affordability and mobility" in Dr. Alamouti's keynote address. Just announced Q2 results from Intel show that the device is having an impact on the company's bottom line, with revenue of $362M (up 65%). Intel's wireless silicon roadmap segments the market in three ways:

  1. Notebooks Calpella platform
  2. Netbooks Pine Trail platform
  3. MIDs Moorestown platform

The Echo Peak V, to be available later this year, will integrate WiFi with WiMAX, GPS and Bluetooth on a single SoC.

WiMAX Technical Advantages, Current Status

The presentation then moved into the technical advantages of WiMAX, current commercial deployments, and the vision for further WiMAX development.

Technical Advantages

  • Cost/bit is claimed to be 3 times better than HSPA (AT&T's 3G system), while Clearwire's cost/bit is 10 times better due to their wealth of 2.5GHz spectrum.

  • The preferred TDD communication method in WiMAX provides the same coverage as FDD, higher download capacity, better MIMO antenna performance, more flexibility, and cheaper devices.

(note: TDD allows better allocation of upload/download spectrum, and is preferred for asymmetric applications such as internet data. FDD is the preferred LTE method, but is better suited for symmetric applications such as voice, since FDD requires paired channels).

Current Deployments

  • Japan's UQ Communications (which recently received $42M from Intel) has deployed more than 1200 WiMAX base stations, and is seeing typical download speeds of 15.8Mbps.

  • Yotta in Russia has deployed 1600 WiMAX base stations, and the service supports the 1st dual-mode GSM/WiMAX handset, the HTC MAX™ 4G.

  • Korea's KT WiBRO service has 200,000 users.

  • In Taiwan, VMAX has 30MHz of 2.5GHz spectrum ,and is beginning commercial WiMAX deployment in Q2-09.

  • In India, BSNL is investing $750M in their WiMAX rollout, soon to make India the largest commercial WiMAX network in the world.

  • Brazil's Embratel has deployed WiMAX in the 12 largest cities, with 20 cities to be covered by the end of 2009.

  • In a test of Clearwire's mobile WiMAX in Portland, on a 17 miles route with average vehicle speed of 35 mph (max 55 mph), the following results were achieved;

Comparison of WiMAX and LTE

The material that Dr. Alamouti presented on the comparison of WiMAX to LTE is similar to publications from the WiMAX Forum. The bottom line is that while LTE has garnered more press recently, no commercial deployments of LTE are expected until 2010 and the two technologies are actually very similar in the potential performance they offer. LTE is saddled with more intellectual property rights issues, and the primary FDD profile that is non-ideal for internet data applications. Both LTE and WiMAX require new Radio Access Networks (90 – 95% of CAPEX), and conversion to an all IP core network (<10% of CAPEX).

Roadmap for WiMAX, IEEE 802.16m

The IEEE 802.16m roadmap, which targets the future ITU-Advanced 4G specification, was covered in more details in another Intel keynote on the 2nd day of the symposium. I will cover that in a later post.

By 2012 real-time video and interactive gaming are expected to dominate mobile internet usage. The 802.16m specification implements backward compatibility to current IEEE 802.16e mobile WiMAX, while targeting peak download speeds of 300Mbps in 20MHz channels. Bandwidth of up to 100MHz will be required to meet the ITU target of 1Gbps download.


The opening keynote was a good introduction to the current state of the 4G world, from the WiMAX/Intel perspective. Mobile WiMAX does have the early lead over LTE in delivering mobile internet capability. Dr. Alamouti put it this way:

"As necessity is the mother of invention, WiMAX is the father of LTE"

LTE gets more attention because it is supported by more of the largest operators (e.g. Verizon, AT&T, Vodaphone). However, that same support is leading to issues that greenfield operators do not face. Lack of SMS support is an issue, along with the need for voice services. Because of this Verizon and other early LTE adopters have emphasized "data only" for first deployments, while T-Mobile is emphasizing that voice is a necessity in order to achieve the lower operating costs of an IP network. Meanwhile, dual-mode and tri-mode WiMAX handsets will be available before LTE sees its 1st deployment.

It might make for more tantalizing headlines, but this is no more a "winner take all" contest than was any previous generation of wireless technology. The 3GPP supporters may hope that one global standard will be defined by the ITU, but as was stated at the symposium: "the ITU will follow what the industry does". Keep in mind that both LTE and mobile WiMAX are currently defined as 3G technologies by the ITU.

WiMAX will co-exist with LTE, and for that matter 4G will co-exist with 3G as well, for many years to come.


1 comment:

wild horse said...

I am not sure whether TDD is more flexible than FDD in practical scenarios, especially in cellular networks since the base stations need to synchronize their transmissions and receptions.