1 Gb/s for Next-Generation Wireless Networks
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National Instruments Alliance Partner SeaSolve Software used LabVIEW to build its WiMAX OFDMA Base Station IQ Generator.
Worldwide Interoperability for Microwave Access (WiMAX) technology continues to push forward as the International Telecommunication Union (ITU) recently included it as part of the IMT-2000 set of standards in October 2007. In December 2006, the IEEE 802.16 Working Group chartered a task force to provide an advanced air interface to meet the cellular layer requirements of next-generation mobile networks. Dubbed 802.16m (sometimes referred to as WiMAX II), this advancement would help catapult the technology into the mainstream cellular market by offering a significant improvement over 802.16e, making WiMAX a big competitor to long-term evolution (LTE) 4G networks. It is expected that 802.16m, or WiMAX II, will deliver data rates up to 1 Gb/s, as opposed to 70 Mb/s with 802.16e, while providing backward compatibility with legacy WiMAX equipment.
Whether WiMAX accomplishes its goals, it does use two exciting technologies that many other wireless networks are also implementing – orthogonal frequency division multiplexing (OFDM) and multiple input, multiple output (MIMO). OFDM is a modulation scheme that packages many orthogonal subcarriers closely together while each subcarrier is modulated with a different modulation scheme. The advantage is OFDM handles channel degradation much better than single-carrier transmissions. In addition, MIMO uses multiple antennae at the transmitter and receiver to increase data throughput due to its spectral efficiency.
Only time will tell if 802.16m gains market acceptance as a viable 4G player; however, don’t hold your breath – there are still several letters left in the alphabet.
This article first appeared in the Q1 2008 issue of Instrumentation Newsletter.
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