Migrating to the 5 GHz Wi-Fi Band Will Advance RTLS and M2M Communications
A crowded RF environment impacts the battery life of Wi-Fi devices significantly—and the first to be affected are those operating in the 2.4 GHz band.
Apr 02, 2012—First it was used in laptops, and then in mobile phones and tablet PCs, but now, Wi-Fi technology is everywhere, in all types of systems that connect to each other to create an Internet of Things. More than a billion Wi-Fi devices were shipped during the past year, and the rate of growth is increasing. A large number of these devices will power machine-to-machine (M2M) communications and real-time location systems (RTLS).
The 802.11 WLAN standard has defined operation in the 2.4 GHz and 5 GHz ISM bands. Additional bands will be added in the future, but these two bands are what are in use today. Most devices currently in operation employ the 2.4 GHz band, for a variety of reasons—a greater likelihood of finding a hotspot or infrastructure access point, lower cost, longer range and lower power consumption. But as the 2.4 GHz band sees increasing amounts of traffic, the quality of a user's experience in connectivity begins to drop. The most visible effects seen include slower connections, a higher number of drop-outs and longer connection times.
Higher traffic also results in a greater number of collisions—each of which wastes energy. Even moderate traffic reduces a tag's expected battery lifespan by more than 45 percent. This is a sufficiently important reason for M2M devices and RTLS solutions to move to the 5 GHz band—where there are 24 channels from which to choose, compared with the three available in the 2.4 GHz band in the United States. (Although there are 11 channels in the U.S. 2.4 GHz band, adjacent channels overlap, thus interfering with each other. Consequently, the use of only three channels—1, 6 and 11—is recommended.)
Apart from the battery-life issue, deployment in the 5 GHz band also helps to reduce user density, and provides better quality of service for throughput- or latency-sensitive applications. Ultimately, operation in the 5 GHz band would significantly accelerate Wi-Fi's adoption for M2M communications and RFID.
Venkat Mattela is the CEO of Redpine Signals. Headquartered in San Jose, Calif., Redpine is a fabless semiconductor and wireless system solutions firm focused on innovative, ultra-low-power and high-performance products for next-generation wireless applications.
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