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The Evolution Of LTE

The Evolution Of LTE

A brief history of cellular radio technologies showing the path to 3G and 4G including LTE.

The Third Generation Partnership Project (3GPP), the international organization that developed the widely used UMTS WCDMA/HSPA 3G standards, also developed Long-Term Evolution (LTE). Release 8 was completed in 2010, followed by release 9. Available now, release 10 defines LTE-Advanced (LTE-A).

Multiple cell-phone technologies designated by generations have led to LTE-A (see the figure). The first generation was analog (FM) technology, which is no longer available. The second generation (2G) brought digital technology with its benefits to the industry. Multiple incompatible 2G standards were developed. Only two, GSM and IS-95A CDMA, have survived.

Cellular radio standards really left FM technologies behind in 1990 with 2G standards like GSM and IS-95A cdma. More than 20 years later, we’re approaching true 4G with LTE-Advanced.

The third generation (3G) standards were created next. Again, multiple standards were developed, notably WCDMA by the 3GPP and cdma2000 by Qualcomm. Both have survived and are still used today. The 3G standards were continually updated into what is known as 3.5G. WCDMA was upgraded to HSPA, and cdma2000 was expanded with 1xRTT EV-DO releases A and B. Both are still widely deployed.

In fact, in many places around the world, carriers are still adding 3G or upgrading their 3G systems. In the U.S., AT&T and T-Mobile use GSM/WCDMA/HSPA while Verizon, Sprint, and MetroPCS use cdma2000/EV-DO. All of these carriers are building LTE networks.

LTE was created as an upgrade to the 3G standards. The cellular industry recognized its major benefits, and virtually every mobile carrier has embraced it as the next generation. All cellular operators are now on the path to implementing LTE. While 3GPP still defines LTE as a 3.9G technology, all of the current LTE networks are marketed at 4G. The real 4G as designated by 3GPP is LTE-A.

Currently, LTE is alive and functioning in many U.S. cellular companies and in others worldwide. The networks are not fully built out, and most of the older 2G and 3G systems are functioning in parallel. Since LTE coverage is not universal, most cell phones incorporate 2G and 3G systems for voice in areas where LTE is not yet deployed. LTE-A deployment is expected in 2014 and beyond.

LTE brings amazing new capabilities to the cellular business. First, it expands carrier capacity, meaning more subscribers can be added for a given spectrum assignment. Second, it provides the high data rates needed by growing new applications, mainly video downloads to smart phones and other Internet access. Third, it makes cellular connectivity more reliable. All of these needs are important to maintaining growth and profitability in the wireless business.  See related article An Introduction to LTE-Advanced:  The Real 4G

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