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A final trend is the exploration of new unlicensed spectrum. Today, WiFi devices utilize unlicensed spectrum in the 2.4- and 5-GHz bands, which offer bandwidths of approximately 100 and 500 MHz in the US, respectively. However, many WiFi devices, especially in the consumer market, use only the 2.4-GHz band due to cost and complex regulations in the 5-GHz band.

Five Trends Shaping 802.11 WLANs, Fig. 4

The latest WLAN standard, IEEE 802.11ac, is limited to the 5-GHz unlicensed spectrum to avoid the congestion at 2.4 GHz.  Although IEEE 802.11ac provides several performance improvements, additional unlicensed spectrum is required to truly take advantage of the wider bandwidth modes and the corresponding high data rates.  Today, spectrum regulators around the world are investigating ways to provide additional unlicensed spectrum in the 5-GHz band. In the US, the Federal Communications Commission (FCC) released a proposal in 2013 to add almost 200 MHz to this band (Fig. 4) and to simplify existing rules.5 Other regulators around the world are also expected to move in a similar direction.

Several GHz of spectrum is available in the 60-GHz millimeter wave band for unlicensed use such as 57 to 64 GHz in the US and 57 to 66 GHz in the EU. Although using this spectrum for consumer devices would have been unthinkable a decade ago, advances in circuit technologies such as introduction of relatively inexpensive millimeter wave CMOS manufacturing have changed that.

Due to the different nature of the 60-GHz band, IEEE 802.11ad defined a unique PHY/MAC stack for this band. For example, the significant propagation loss at 60 GHz is mitigated by key enabling technologies such as adaptive beamforming. In this case, antenna arrays create highly directional beams that are rapidly adapted to the changing channel between the communicating devices. Target use cases for this technology includes short-range communications such as high-speed wireless cable replacement (e.g., wireless HDMI, wireless docking) and wireless interactive displays.7  The market rollout of this technology is expected to accelerate in 2015.

Although WiFi technology and equipment have been available for more than a decade, the innovation in this market space is only accelerating. As this article has detailed, five specific trends will likely shape the growth of WiFi technology in the future.  Although these are the five biggest trends today, the progression of technology has a way of surprising everyone. Since IEEE 802.11 follows an open process, interested readers are encouraged to visit the working group website1 or attend a standards meeting to review and track the progress.

Amal Ekbal, Senior Wireless Platform Architect

National Instruments, 11500 N. Mopac Expy., Austin, TX 78759.

References

1. IEEE 802.11 Working Group.

2. E. Perahia and R. Stacey, Next Generation Wireless LANs, 2nd Ed., Cambridge University Press, Cambridge, UK, 2013.

3. E. Perahia, et al., “High Efficiency WLAN Overview,” February 2014.

4. Qualcomm, San Diego, CA, The 1000x Data Challenge.

5. P. Ecclesine and J. Kenney, “Tutorial on 5 GHz,” March, 2013,

6. United States Department of Transportation, Connected Vehicle Technology.

7. WiFi Alliance, Wi-Gig Certified 60 GHz.

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