Electronicdesign 3829 Xl 5g

Are You Ready For 5G Wireless?

Nov. 15, 2010
A look at what is 4G wireless and what 5G may be.

5G wireless—are you kidding me? We haven’t even implemented 4G, according to some sources. So what’s with 5G? Frankly, I really don’t know. It is evidentially the next step beyond 4G and probably entails a further boost in wireless data rates to as much as 1 Gbit/s and some other exotic stuff that hasn’t emerged from the research labs yet. I’m not sure we need it and the infrastructure certainly cannot accommodate it anytime soon, at least until everyone has first passed through the 4G stage. But then what is 4G, really?

The Real Meaning Of 4G
There has been a great deal of discussion lately as to what 4G wireless really is. In general, it is the next step beyond 3G wireless, of course. The first generation was analog FM cell phones based on the old AMPS standard and a few other specs. The second generation or 2G was the introduction of digital cellular, which included GSM and cdmaOne and a few other foreign standards. It really revolutionized the mobile business, expanding not only the subscriber capacity but also making calls far more reliable. And, it brought with it the first meager data transmission standards like GPRS.

Next came 3G, which was defined by the Third Generation Partnership Project (3GPP) and the International Telecommunications Union (ITU). The ITU essentially established a standard that explained 3G as WCDMA with a data rate to 2 Mbits/s. The other standard to meet the 3G definition was cdma2000 of Qualcomm.

We are essentially in 3G right now with most carriers now offering some form of 3G services. 3G also includes newer additions to the standard called High Speed Packet Access (HSPA) and Qualcomm’s EV-DO with Rev A and Rev B. HSPA modifies the basic standard to include various levels of quadrature amplitude modulation (QAM) to further boost data rates up to about 42 Mbits/s. Many carriers now offer HSPA.

4G is the next generation beyond 3G. We generally agree that it is a full Internet Protocol (IP) technology with download speeds up to 100 Mbits/s and uploads to 50 Mbits/s. Two technologies are generally viewed as 4G: Long-Term Evolution (LTE) and WiMAX. The ITU says they aren’t 4G, though. Who really has the authority to say what is 4G or not?

The big contention is that Clearwire and Sprint are offering a WiMAX cellular network and claiming it is the first 4G wireless network. Many agree. Furthermore, now T-Mobile is offering its latest HSPA+ upgraded network as 4G. AT&T is not promoting its HSPA network as 4G, thus the big dispute.

Is it really false advertising for Sprint, Clearwire, and T-Mobile to say their networks are 4G? Maybe, maybe not. After all, it’s only marketing and HSPA+ and WiMAX are technologies just beyond 3G.

The ITU’s Definition
The ITU basically says that LTE and WiMAX are advanced versions of 3G. Some call it 3.9G. As the standards body, the ITU can assert that, but it is surely not a rule of international law. The ITU isn’t going to sue Sprint, Clearwire, or T-Mobile. The IEEE, which standardizes WiMAX or 802.16, hasn’t said that WiMAX is 4G either.

To be technically correct, LTE and WiMAX are 3G, but 3G is boring. We want the next best thing. HSPA+ is certainly the next good thing beyond basic WCDMA 3G, and why not call it 4G? LTE and WiMAX are different and new technologies based on orthogonal frequency-division multiple access (OFDMA) and multiple-input multiple-output (MIMO). They really are 4G, at least in most people’s minds.

Continue on next page

The real downside to all this is that it confuses the daylights out of the consumer. How do cell-phone buyers really know what to buy? Most can’t even identify what cellular technology they use anyway. Cellular subscribers couldn’t care less about how it works or what it is, as long as it has the speed to handle the services they want.

Cost is also a key consideration. 3G or 4G—who cares? Consumers want the latest and greatest thing and 4G is it, whatever the carrier says it is. What happens when real 4G comes along? Oh boy. Caveat emptor, for sure.

So what is “real” 4G? The ITU says that it comprises advanced versions of LTE and WiMAX. LTE-Advanced or IMT-Advanced is the real 4G version of LTE. 802.16m or WiMAX is also called WirelessMAN-Advanced, and that is true 4G. Both are expected to offer fixed data rates of up to 1 Gbit/s and 100 Mbits/s mobile plus other advanced features.

These standards are still in the development stages and aren’t expected to be ratified until years from now. LTE-Advanced may make an appearance later in 2011, but we won’t see WirelessMAN-Advanced until 2012. And we won’t actually see those technologies implemented in real phones and the infrastructure for years beyond those dates. What will the marketers do in the meantime?

I don’t have any problem with the cellular operators calling LTE and WiMAX 4G. It is indeed the next big wave or generation of wireless featuring new technologies over 3G. Who cares what a fine point the ITU puts on it? Saying HSPA+ is 4G is a stretch, however, even if a carrier considers it the fourth generation of network upgrades. But who’s to say it isn’t? Why don’t we just go with the 4G term for LTE and WiMAX and call the advanced versions to come 5G?


To join the conversation, and become an exclusive member of Electronic Design, create an account today!