Editor's note: This SearchTelecom.com Expert Lesson, LTE: The preferred 4G solution for wireless operators, provides
a comprehensive look at Long Term Evolution (LTE). This article compares LTE and WiMAX technologies and analyzes why many mobile operators are choosing LTE. This guide also looks at deploying LTE-based services to take advantage of 4G capabilities, optimizing metro infrastructure for LTE performance and analyzing geographic and customer requirements for LTE deployment planning.
Estimates that 80% of world mobile operators will deploy LTE are probably conservative.
The primary question has not been if operators should migrate to 4G, but rather when and using which technology. To make it more complex, the answers may even be inter-dependent.
Most people today are more familiar with the 4G WiMAX standard than with the 3GPP standard called Long Term Evolution (LTE). The reason is that WiMAX is perceived as a kind of successor to the common WiFi standard and that some early deployments of WiMAX have already begun. But WiMAX is more likely to be deployed in developing countries and where it provides a parallel network to current mobile networks. Estimates that 80% of world mobile operators will deploy LTE are probably conservative. Even those who elect to deploy WiMAX in some areas are still likely to deploy LTE as an evolution to their current 3G networks.
At the technical level, WiMAX and LTE standards are very similar. Both would support 100 Mbps transmission rates (WiMAX in 2009 with the 802.16m version). Both are based on the same OFDMA modulation 4G interface. In theory, WiMAX supports slightly larger cells, but LTE supports more users per cell.
Three reasons driving operators' LTE choices
With the similarities of the two, why is there such a clear operator preference for LTE? Here are the three primary reasons.
- Wireless operators are the primary movers behind the LTE standard. For all practical purposes, mobile data services today are built totally from operator-backed standards.
The 3rd Generation Partnership Program (3GPP) and CDMA Development Group (CDG) are built around the operators that deploy GSM and (CDMA2000), respectively. Because the operators have driven these bodies to address issues that are important in their deployment plans, the standards are completely congruent with their goals and issues.
WiMAX is an open standard of the IEEE, which generally takes a broader view from many classes of contributor companies. Many operators believe that WiMAX was designed to serve too many masters: to support fixed and mobile wireless, as well as licensed and unlicensed spectrum. Some are also concerned that the mobile form of WiMAX may not be adequate for high-speed vehicle use, or that spectral efficiency may be too low for use where spectrum space is tight..
- LTE was specifically designed to provide an easy evolution to 4G from 3G technology that is already in place. For mobile operators with massive investments in 3G, it is simply not financially realistic to assume that the previous generation of technology would be discarded and replaced en masse. Such a move would be financially impossible and create major user hardships, since the spectrum available would not normally permit parallel operation. An evolutionary approach is the only approach that makes sense for a wireless incumbent.
- LTE's timetable is largely congruent with the goals of operators' 4G evolution. Much has been said about the advantage WiMAX enjoys because of its earlier ratification. But the early form of the WiMAX standards were not suitable for mobile service, and the version of WiMAX that is most equivalent to LTE in performance is likely to be ratified late in 2009. Most operators planned LTE deployments in 2010 or 2011, by which time both full LTE standards sets and broader sources for the handset chipsets are expected to be ratified and available.
Where LTE and WiMAX makes sense
To understand why LTE is the operators' choice, you also have to understand why there have been early WiMAX deployments and not early LTE deployments. In large part, this is because of the multi-mission nature of WiMAX. Consider the following examples:
- In many emerging economies, WiMAX is viewed as an alternative to wireline broadband where no physical wiring exists.
- In some developed countries like the U.S., WiMAX targets a different market niche, the "migratory" laptop or netbook user (or, a "portable" customer who moves between preferred resting places). Migratory users have networking needs that create a distinctive set of usage equipment and service requirements compared to truly mobile users who literally move while on the network.
- Finally, it is an easy choice for non-incumbent operators -- those providers who aren't trying to migrate their 3G services because they don't have any 3G services.
Contrary to some beliefs, LTE is not a "walled garden" (or closed network standards set) and WiMAX an "open" network standards set. Nearly all LTE providers will support open handset initiatives, and today all smartphones have open developer programs that allow applications to be created by third parties.
If LTE operators have tighter control over the radio frequency (RF) and channel management aspects of their handsets, it is because mobile services have become the dominant means of communications for a large portion of the world's population, and the stability and security of the networks that support these services is absolutely critical for their continued success.
About the author: Tom Nolle is president of CIMI Corporation, a strategic consulting firm specializing in telecommunications and data communications since 1982. He is the publisher of Netwatcher, a journal addressing advanced telecommunications strategy issues. Check out his SearchTelecom networking blog Uncommon Wisdom.