New FCC Rules for unlicensed radio equipment operating in the 5.15 – 5.85 GHz frequency bands

By David Bare, Chief Engineer, NTS Silicon ValleyThe FCC recently adopted revised rules for products that operate in unlicensed frequency bands from 5 – 6 GHz per Part 15 Subpart E of the FCC Rules. The rules were published in the Federal Register of the US Government and will become effective on June 2, 2014. The main objectives of the revised rules was to consolidate the rules for the frequency band 5725 – 5850 MHz, to allow operation in more of the 5-6 GHz spectrum and to allow additional output power and outdoor operation in the 5150-5250 MHz band. All three objectives were met but the extension of operation to more frequencies was limited to just adding the 5600-5650 MHz band. The FCC is working on draft test procedures to accommodate the changes in the rules.New products may be approved (Certified) using these new rules as soon as the test procedures are finalized after June 2, 2014. New and existing products can continue to be approved and sold under the old rules until June 2, 2015. Existing products may continue to be sold and approved with modifications until June 2, 2016. After June 2, 2016, all products sold must comply with the new rules. There is no “grandfathering” of products after this deadline.Taking a more detailed look at the rule changes.In the 5150-5250 MHz band, the new rules allow conducted power up to 1 watt and radiated power up to 4 watts for access points. However, the rules limit radiated power above a 30° elevation above the horizon to 0.125 watts for outdoor use. This creates a requirement for the beamwidth of the antenna(s) used with the product if your power will exceed 0.125 watts. The draft procedure provides guidance on making measurements, performing calculations or simulations to show the radiated power versus elevation angle. Fixed point to point products in this band are allowed 1 watt of conducted power and 200 watts of radiated power.In the 5150-5250 MHz band, the new rules allow conducted power up to 250 milliwatts and radiated power up to 1 watt for mobile and portable client devices.An increase in power over the value on the existing approval (as shown on the FCC Grant) may be done by filing a permissive change application since the rules will change to allow higher output power. It should be noted that normally, the output power of a product cannot be increased without obtaining a complete new approval.In the 5725-5850 MHz band, the minimum bandwidth is effectively reduced to 500 kHz as no power reduction is required unless the bandwidth is less than 500 kHz.In the 5725-5850 MHz band, the emissions limits in the spectrum adjacent to the band are lower than those allowed by §15.247 of the old FCC rules for this band.A new requirement for a description of the security procedures employed in the product to prevent unauthorized modifications of the RF parameters has been added.Dynamic Frequency Selection detection bandwidth has been increased to minimum of the 99% power bandwidth from a minimum of 80% of the 99% power bandwidth. The step size used during detection bandwidth testing may be increased to 5 MHz reducing to 1 MHz as you near the edge of the detection bandwidth.A new type 1 radar has been specified for Dynamic Frequency Selection.Dynamic Frequency Selection channel loading requirements have been changed. A minimum channel loading of 17% must be demonstrated. Typical data shall be used instead of only using the FCC designated MPEG file or method approved by the FCC. If desired, other software to generate data can be used but must be random in nature.To take advantage of the provisions of the new rules, you must address all of the changes. You may not mix the old and new rules. Depending on your product, complying with the new rules may only take a few measurements and security software changes or it may take full DFS, power, radiated power versus elevation, spurious emissions and SAR testing. In any situation, a permissive change application is required. Please contact your NTS representative with your product information for more details on applicable tests.NOTE:Although the FCC is changing their Rules, Industry Canada will not change their requirements in the short term to match the changes made by the FCC. Industry Canada indicated they are planning on writing a new RSS-247 that will likely be harmonized with the new FCC Rules. This affects products that are sold with a single SKU for the US and Canadian markets and you want to use the new FCC Rules.For more information about how this change affects your products or for a price quote for services, please contact us via email or call at 510-578-3500.