This is the first of a series of articles that will address Long Term Evolution (LTE), Long Term Evolution – Advanced (LTE-A), Voice over LTE (VoLTE), Worldwide Interoperability for Microwave Access (WiMAX), small cell networks, Self Organizing Networks (SON), Centralized Radio Access Networks (C-RAN) and Heterogeneous Networks (Het-Nets). Since some of these are 4th generation (4G) technologies, it is appropriate to spend a little time here to get a good reference point. In this article we will briefly address who defines a generation, what constitutes a generation, as well as the major 4G requirements. In the next article, entitled Wireless Generations – Part II, we will address a brief history of the wireless industry.
Who Writes these Standards?
The International Telecommunications Union-Radio (ITU-R) is an agency of the United Nations which was formed to promote and regulate telecommunications standards across nations. It writes the specifications for the new generation, but it does not have any control over implementing the standards. In a way, it sets the goals and objectives of the next generation and other parties have to figure out how to get there.
In 2008 the ITU-R published International Mobile Telecommunications – Advanced (IMT-A), a document that defined the coming 4G wireless network specifications that are commonly known as the 4G wireless standards. As with most human endeavors, there is always some give and take with standards. After the ITU-R published the 4G standards, several network companies that were implementing LTE, evolved high speed packet access (HSPA+) and WiMAX technologies argued that they should be able to market them as 4G technologies although they didn’t meet all of the original criteria of the standard. The ITU-R later agreed to allow these companies to do so.
What is Necessary to Make a New Generation?
A new generation of wireless telecommunications generally refers to a fundamental change in the nature of the service. In a sense, the change has to be revolutionary and not just evolutionary. Each generation must typically meet the following criteria:
The transmission technology must not be backwards-compatible.It should have considerably higher peak bit rates.It will use new frequency bands and/or wider channel frequency bandwidths.It will have higher system spectral efficiency (higher bit/second/Hertz/site).
It is only reasonable that each new generation is substantially and not necessarily totally revolutionary. 3G technology had many elements that were backward-compatible with 2G technologies. All of society, and technology, stands on the shoulders of our predecessors.
What are the 4G standards?
The 4g standards published by the ITU-R in 2008 included the following requirements. The network must be/have:
Based on an all-IP packet switched network. Peak data rates of up to approximately 100 Mbit/s for high mobility (cars, subways, trains etc.) and up to approximately 1 Gbit/s for low mobility (walking).Able to dynamically share network resources to support more simultaneous users per cell.Scalable channel bandwidths of between 5–20 MHz and optionally up to 40 MHz.Peak support spectral efficiency of 15-bit/s/Hz in the downlink, and 6.75-bit/s/Hz in the uplink.Support smooth handovers across heterogeneous networks.Capability to offer high quality of service for next generation multimedia support.
The reader may want to compare these to the fundamental requirements necessary to constitute a new generation. Also, we will return to these in a future article about LTE.
So here we are, but how did we get here? In the next article, The Wireless Generations – Part II, we will digress a bit and look at some of the developments that got us to the 4th Generation. We will use the “wireless generations concept” for context to look at some of the non-technical actions that made it all possible. This is dear to us since these were the developments that spawned Vertex Innovations.