September 28, 2016

4G sign

HSPA+, WiMax, TD-LTE, 4G LTE, LTE-Advanced? If you have been browsing through different smartphones and carrier contracts, you have probably spotted a number of these terms scattered throughout advertisements and spec sheets. These days, fast mobile data connections are easy to come by in many countries around the world, but all of these terms and network types can mean slightly different things for your data speeds. We’re here to breakdown what, if any differences there are between the sometimes interchangeable and often misused 4G and LTE terms.

The trouble deciding standards

Although the International Telecommunications Union-Radio (ITU-R) decided upon the specifications for 4G back in 2008, we have seen a number of different names appear for networks that promise 4G data speeds, many of which provide very different results to consumers.

The problem with creating standards is twofold. Firstly, the standards aren’t strictly enforceable as the ITU-R has no control over carrier implementations. Secondly, the transition from an old standard to a new one doesn’t happen overnight. There’s a long period where early networks don’t necessarily match up with what consumers expect. Although most advanced 4G LTE markets are over this stage now, these networks types are still developing in some countries and the issue is bound to rear its head again as we move towards 5G.

LTE and WiMax growth paths Many “first generation” 4G technologies, such as Mobile WiMAX and HSPA+, didn’t quite match up to the full specifications. This situation only became more complicated in October 2010, when the ITU-R completed its assessment of six different candidates to actually use to meet the full requirements of the planned 4G standard.

After much deliberation, LTE-Advanced and WirelessMAN-Advanced (WiMax Release 2) were designated as the IMT-Advanced compliant technologies, and the age of real 4G began. However, HSPA+, WiMAX, and LTE were also allowed to be labelled as 4G technologies, despite not offering the full feature set promised by the “official” technologies. This was due to the fact that many carriers and hardware manufacturers had already begun investing in these networks during the two and a half year deliberation.

Read more:

State of Mobile Networks - USA March 2016

March 3, 2016

The “true 4G” standard

So, LTE-Advanced and WirelessMAN-Advanced are the networking technologies that actually meet the “true 4G” specifications, with the former being the type that you are going to see in consumer markets. So if you’re running an LTE, WiMAX, or HSPA+ connection, you’re not really up to speed.

Interestingly enough, even LTE, which is commonly marketed at 4G LTE, doesn’t satisfy the technical requirements decided upon in this specification. To differentiate LTE Advanced and WiMAX-Advanced from current 4G technologies, the ITU has defined them as “True 4G”. Although you will very rarely ever see this term used. Hence the confusion in the early days of 4G network roll-outs.

StandardHSPA+WiMAX Rel 1LTELTE-AdvancedWiMax Rel 2"True 4G"
Download84 Mbps128 Mbps100 Mbps1000 Mbps1000 Mbps1000 Mbps
Upload22 Mbps56 Mbps50 Mbps500 Mbps500 Mbps500 Mbps

However, even the Release 8 of the LTE-Advanced standard only support maximum download speeds of 300Mbit/s, which is below the IMT-Advanced standard. It wasn’t until the Release 10 specification that LTE-A networks were define to provide peak download capabilities of 1Gbit/s download and 500Mbit/s upload. As such, network hardware is split into categories depending on their capabilities and you won’t see devices or networks automatically jump up to meet these specs. In other words, LTE and WiMax standards are gradually improving to meet the IMT-Advanced specification.

LTE ClassSpeedsAggregation Options
Category 12600 Mbps download
100 Mbps upload
3 x 20MHz download
2 x 20MHz upload
Category 10450 Mbps download
100 Mbps upload
3 x 20MHz download
2 x 20MHz upload
Category 9450 Mbps download
50 Mbps upload
3 x 20MHz download
Category 7300 Mbps download
100 Mbps download
2 x 20MHz download
2 x 20MHz upload
Category 4150 Mbps download
50 Mbps upload
2 x 10MHz download

Furthermore, this isn’t a guide for the speeds that consumers will actually see. Instead, customers are more likely to be able to use speeds approaching 100 Mbit/s on mobile devices with a strong LTE-A connection, while the 1Gbit/s speed is defined for low mobility wireless access points.

The standards must also provide backwards compatibility with the investments into early “4G” technologies. Therefore LTE and LTE-A implementations can share bandwidth, which has contributed to more affordable gradual roll outs.

Here are the latest LTE-Advanced specification from 3GPP:

  • Increased peak data rate, DL 3 Gbps, UL 1.5 Gbps
  • Higher spectral efficiency, from a maximum of 16bps/Hz in R8 to 30 bps/Hz in R10
  • Increased number of simultaneously active subscribers
  • Improved performance at cell edges, e.g. for DL 2×2 MIMO at least 2.40 bps/Hz/cell.

The big enabler for these type of speeds in consumer hardware is carrier aggregation, a term you have probably spotted on high-end smartphone specifications sheets. Carrier aggregation enables receiving handsets to make better use of fragmented carrier bands, in order to downloaded data faster through the use of multi-antenna techniques (MIMO) and Coordinated Multi Point (CoMP) technologies. The LTE-A standard supports up to 5 carriers and up to 100MHz. Some high-end modems will support 2 or 3 carriers these days and can therefore provide some pretty speedy data connections.

LTE carrier aggregation

It’s also important to note that LTE-A isn’t just about handset download speeds. There is also a big push to make improvements to infrastructure in order to achieve these high download rates. LTE-A aims to improve data speeds by using a mix of traditional macro cells and vastly improved small cells. The aim is to offer better high speed coverage at the network’s edge and more bandwidth, but the transmitters will have to function on different frequency bands in order to avoid interference.

A look at the market in 2016

The past three years has seen a much wider roll-out of LTE networks and a number of countries and carriers have begun offering carrier aggregated networks to consumers too. According to the latest report from GSA, 1 in 3 global network operators are investing in LTE-Advanced networks and 25 percent of them have already launched such networks to consumers. However, infrastructure speeds are still quite far behind the 1Gbit/s speeds required to fully meet the official specification.

See also:

Fastest LTE networks and countries revealed

September 24, 2015

All of the countries that topped the rankings for mobile network speeds last year are offering LTE-Advanced capabilities. These countries include Australia, Canada, China, Japan, New Zealand, and South Korea. A considerable number of European countries now have Cat 4 and Cat 6 LTE network operating across numerous carriers as well. Many of which began going online throughout 2015.

In the US, AT&T offers Category 4 LTE with carrier aggregation, as does Sprint, T-Mobile and Verizon. Although, these appear to only be available on a limited number of bands and therefore aren’t available universally across the country. Unfortunately, the US appears to be languishing behind other countries when it comes to investing in and rolling out faster LTE-Advanced deployments, though this has started to change.

GSA LTE Advanced rollout map

Although true 4G is sort of here, there’s not really an absolute speed that we can point at to say “that’s a proper 4G network” in reality. These days’ customers can seamlessly move in and out of LTE and LTE-A network coverage and there’s quite a wide variation in consumer speeds because of this.

Instead, it’s perhaps best to view this generation of wireless technology as an evolving and ever improving standard. One that will move relatively seamlessly, at least from a consumer point of view, from pre-4G through to next-generation 5G technologies as network providers continue to upgrade their network technology.

Robert Triggs
Lead Technical Writer at Android Authority, covering the latest trends in consumer electronics and hardware. In his spare moments, you'll probably find him tinkering with audio electronics and programming.
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