But first, some background: 4G is the short name for fourth-generation wireless, the stage of mobile communications that will enable things like IP-based voice, data, gaming services and high quality streamed multimedia on portable devices with cable modem-like transmission speeds. It's a successor to 2G and 3G wireless, whereby the first signified the shift from analog to digital transmissions, bringing data services like SMS and email to mobile phones for the first time, and the second refers to the advent of things like global roaming as well as higher data rates.
Think of wireless generations as a handful of services that get faster and more feature-rich as newer technology becomes available. The 3G networks that we use today allow us to stream video, download music and files, and surf the web at average download speeds from 600Kb/s to 1.4Mb/s. With 4G you'll be able to do the same but at much faster rates, while the extra bandwidth opens the door for newer applications.
There are a number of standards and technologies pertaining to each wireless generation -- GSM, cdmaOne, GPRS, EDGE, CDMA2000, UMTS (also marketed as 3GSM), HSDPA, among others. For practical reasons, we won't be dwelling on the technicalities of each term and instead will move onto the ones that involve our topic of interest here: 4G.
Although no set of standards have been established as of yet by the International Telecommunication Union (ITU), the authority on such things, two competing technologies have been proposed: LTE and WiMAX. Many service providers often use the term 4G mobile broadband to describe the technologies they are offering based on their own, sometimes distorted definitions. However, current implementations are largely considered pre-4G, as they don't fully comply with the planned requirements of 1Gbit/s for stationary reception and 100Mbit/s for mobile.
Besides speed, several other guidelines have been traced for wireless communication standards to qualify as 4G. In a nutshell, they should be very spectrally efficient, should dynamically share and utilize the network resources to support more simultaneous users per cell, have smooth handovers across heterogeneous networks, offer high quality of service for next generation multimedia support, and should be based on an all-IP packet switched network.
Short for Long-Term Evolution, LTE is considered by many to be the natural successor to current-generation 3G technologies, in part because it updates UMTS networks to provide significantly faster data rates for both uploading and downloading. The specification calls for downlink peak rates of at least 100Mb/s and an uplink of 50Mb/s, but going by real world tests its transfer speeds will more likely range from 5-12Mb/s for downloads and 2-5Mb/s for uploads.
LTE is being developed by a group of telecommunications associations known as the 3rd Generation Partnership Project, or 3GPP, as an eight release of what has been evolving since 1992 from the GSM family of standards.
There are two fundamental aspects of LTE. The first is that the technology finally leaves behind the circuit switched network of its GSM roots and moves to an all-IP flat networking architecture. This is a significant shift which in very simple terms means that LTE will treat everything it transmits, even voice, as data. The other big change relates to the use of MIMO technology, or multiple antennas at both the transmitter and receiver end to improve communication performance. This setup can either be used to increase the throughput data rates or to reduce interference.
Many big-name global operators and mobile communications companies are backing LTE in the race for 4G mobile broadband, including Vodafone, Orange, T-Mobile, LG Electronics, Ericsson, Nokia, Siemens, NTT DoMoCo, and others. In the U.S., Verizon Wireless has said it is going commercial with its LTE network in the fourth quarter, with 25 to 30 markets up and ready at launch. AT&T and T-Mobile claim they will begin to deploy LTE in 2011, but in the meantime both networks have moved to HSPA 7.2 and the latter plans to roll out HSPA+ beginning this year. Theoretically these can support speeds of up to 7.2 and 21 Mbps, respectively, but in real world scenarios they are only marginally faster than most 3G data services.
The reason behind LTE’s strong industry support lies in the relative ease of upgrading from current 3G networks worldwide over to LTE mobile broadband, compared to the significant infrastructure build out that WiMAX has taken thus far. Fewer cell sites have to be built and penetration into buildings is better at the 700 MHz spectrum LTE uses. However, WiMAX deployments are already up and running while LTE's formal debut is still a few months out.
WiMAX is a wireless broadband access standard developed and maintained by the IEEE under the 802.16 designation. As its name suggest, WiMAX can be thought of as an extension of Wi-Fi designed to enable pervasive, high-speed mobile Internet access on a wide range of devices, from laptops to smartphones. The current implementation is based on the 802.16e specification which offers theoretical downlink rates upwards of 70Mbps and up to 30-mile ranges.
Again, "theoretical" is the keyword here as WiMAX, like all wireless technologies, can either operate at higher bitrates or over longer distances but not both. Production networks being operated in the United States are seeing average speeds go from 3 to 6Mb/s, with bursts up to 10Mb/s. Like LTE -- and Wi-Fi 802.11n for that matter -- WiMAX supports MIMO technology, which means that additional antennas can increase the potential throughput.
There is no uniform global licensed spectrum for WiMAX, but three have been listed: 2.3 GHz, 2.5 GHz and 3.5 GHz. In the U.S., the biggest segment available is around 2.5 GHz and is already assigned primarily to Clearwire, a wireless internet service provider in which Sprint Nextel holds a majority stake.
In terms of total available 4G spectrum to deploy their services, Clearwire has several times more than its competitors, which have smaller portions of the 700 MHz band. However, Verizon and AT&T are not too worried about this as they can re-utilize spectrum being used right now for 2G and 3G services by upgrading these to LTE when the demand is there.
Furthermore, as mentioned earlier, the 700 MHz band that both Verizon and AT&T plan to use has enormously better range and penetration of buildings than the same power of signal at 2.5 GHz. Some experts have said that 700MHz will require as few as one-quarter as many base stations to offer identical coverage to 2.5 GHz.
As you might have guessed, the industry players behind these 4G technologies reflect the history of each standard. Whereas LTE biggest supporters are, in general, telecommunication service companies and handset manufacturers, WiMAX counts the likes of Intel, Cisco and Google among its most important backers. It should be noted though that many companies like Nokia or Motorola are members of both industry groups, with different levels of involvement.
The 'Real' 4G, Products and Availability
Like we mentioned before, neither WiMAX nor LTE are truly considered a 4G technology by the International Telecommunications Union. As defined in their International Mobile Telecommunications Advanced (IMT Advanced) family of standards, these technologies must have target peak data rates of approximately 100 Mb/s on high mobility devices like cell phones and approximately 1 Gb/s for stationary devices like a 4G modem at home.
Just like the so-called 2.75G EDGE standard was developed to provide speeds several times faster than 2G data (GPRS) before 3G could be deployed, current implementations of WiMAX and LTE are largely considered a stopgap solution that will offer a considerable boost while WiMAX 2 (based on the 802.16m spec) and LTE Advanced are finalized. Both technologies aim to reach the objectives traced by the ITU, but are still far from being implemented.
In the United States, both T-Mobile and AT&T have moved to UMTS and various flavors of paired HSDPA / HSUPA, while on the CDMA front Sprint Nextel and Verizon Wireless support the EV-DO network. Download speeds vary from carrier to carrier depending on several factors, but on average they are somewhere between 600Kb/s and 1,400Kb/s.
In the case of Sprint, however, they've opted to go the WiMAX route because it was a near-term solution for which the company had enough spectrum to deploy right away. So while the 'real' 4G may still be a long ways off, we'll take all the speed we can get at the moment. Today that's 3-6Mb/s with Clearwire's WiMAX service.
We expect operators to maintain their existing 2G or 3G networks for the foreseeable future, to support voice and narrower-band data while providing ubiquitous coverage. WiMAX and LTE will initially be deployed as an overlay network for fast data transfer rates, with multi-mode handsets (EV-DO / WiMAX or HSPA / LTE, for example) enabling users to get the best of both worlds as operators build out their 4G networks over several years.
Products and Availability
The biggest WiMAX provider in the U.S. is Clearwire, with their Clear service currently available in 30 markets including big cities like Atlanta, Las Vegas, Portland and most recently Houston. By the end of the year the company expects to expand its coverage to 80 major markets, reaching over a hundred million potential customers. Comcast, Sprint, and Time Warner Cable act as wholesale providers selling access to the same underlying WiMAX network as well.
Clear's mobile and residential plans can be purchased by the day or by the month, with several no-contract options available. Home Internet service plans start at $30 per month for unlimited data, while mobile Internet plans start at $40 per month and a combination of the two is available from $55. True road warriors can also sign up for a dual-mode plan, offering the speed of Clearwire's WiMAX network where available and 3G mobile Internet connectivity elsewhere.
Besides from choosing the plan that fits you, new gear is required to access this service. The easiest way to get up and running is with one of several USB dongles, which are available at low prices from Clear itself when signing up to a plan, or separately starting at $50 and all the way up to $225 for WiMAX and 3G coverage with the same device. There is also a range of stationary modems for home or office use, as well as Sprint's Overdrive device, which serves as a portable hotspot for up to five Wi-Fi-enabled devices to hop on Clearwire's WiMAX and 3G networks.
If you want support built inside your laptop, there are an increasing number of options out there with mobile WiMAX technology from Intel available out of the box or as an option. These range from netbooks to business-oriented laptops like the Lenovo ThinkPad Edge, which sells for around $900, and all the way up to luxury desktop replacements.
Sometime during this spring, Sprint is expected to release the first "4G" phone in the U.S. -- and it's a monster. Dubbed HTC EVO, this Android-based phone will sport a large 4.3-inch screen, 1Ghz Snapdragon processor, 512MB of RAM, an 8-megapixel flash-equipped camera capable of recording 720p video, a 1.3-megapixel front facing camera for placing video calls, and offer tethering of its speedy WiMAX signal to double as a portable hotspot. Of course, this will be a dual-mode smartphone, so outside of WiMAX areas the EVO will fall back to Sprint's EV-DO Rev. A network.
On the other side of the fence, Verizon is expected to launch its LTE network in 25 to 30 markets before the end of the year. There's not much we can tell in the way of pricing or product details yet, but we know the carrier doesn't plan to launch its first LTE-based cell phone until mid-2011. Meanwhile, MetroPCS is also getting ready to roll out its LTE network in "various metropolitan U.S. markets" this year and is partnering with Samsung for the first compatible phone.
A Future of Convergence?
On the other hand, GSM network standards dominate over 80% of the cellular markets worldwide, so it's only natural that most mobile operators will want to move to LTE, as it's rooted on the same technology they've worked with for over a decade -- Verizon being the obvious exception with their network based on CDMA standards. Another important factor, as mentioned earlier, is that LTE requires significantly less infrastructure and thus will be cheaper to deploy.
Because both technologies are so similar there has been talk about them converging in the future. Clearwire CEO Bill Morrow emphasized this idea at the recent CTIA Wireless trade show, saying that the wireless industry should focus on the similarities between WiMAX and LTE rather than their differences. Motorola has added to this concept saying that they re-use much of its WiMAX technology when building LTE gear. Morrow envisions both technologies merging into one network standard, but even if that doesn't pan out, he says they can add LTE to their network if necessary.
Verizon was quick to express doubt this will ever happen, but ultimately it's up to the standards bodies and the driving forces behind them. Regardless if such convergence ever gains traction, for now WiMAX is at least a year ahead of LTE in terms of major commercial deployments and is moving full steam ahead. Clearwire will likely market WiMAX devices (and later on WiMAX 2) exclusively for the next 2-3 years, adding an LTE signal with minimal change to its antennas when -- and if -- the market demand is there as the LTE device ecosystem matures.
The leap to WiMAX in its current state is really more like going from dial-up to DSL. It's a nice speed gain, comparable to some of the lower-end home broadband plans, but more of an intermediate step to something much faster. In the short term that could be LTE. We'll have to reserve judgment until it's available commercially, but the fact remains neither technology will make users want to drop their speedy cable modem service just yet.
If you are not looking to do extremely demanding broadband usage, and spend most of your time within Clear's WiMAX coverage area, then the increased data speeds could be attractive for working at home or on the road without having to worry about finding a Wi-Fi hotspot. Sprint's upcoming HTC EVO handset might also play an important role in getting new customer sign-ups, as the first and probably only smartphone capable of 3-6Mbps download speeds that can also double as a portable Wi-Fi access point for as many as eight devices.
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