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Electronic Code of Federal Regulations

e-CFR data is current as of December 11, 2019

Title 47Chapter ISubchapter APart 15Subpart H → §15.709


Title 47: Telecommunication
PART 15—RADIO FREQUENCY DEVICES
Subpart H—White Space Devices


§15.709   General technical requirements.

(a) Radiated power limits. The maximum white space device EIRP per 6 MHz shall not exceed the limits of paragraphs (a)(2) through (4) of this section.

(1) General requirements. (i) White space devices may be required to operate with less power than the maximum permitted to meet the co-channel and adjacent channel separation requirements of §15.712 of this part.

(ii) Mode I personal/portable devices are limited to 40 mW, if the white space device that controls it is limited to 40 mW.

(2) TV bands and 600 MHz service band. (i) Fixed devices: Up to 4 W (36 dBm) EIRP, and up to 10 W (40 dBm) EIRP in less congested areas in the TV bands and 600 MHz service band at locations where they meet the co-channel and adjacent channel separation distances of §§15.712(a)(2) and 15.712(i) of this part, respectively. Operation in the 602-620 MHz band is limited to a maximum of 4 W (36 dBm) EIRP.

(ii) Personal/Portable devices: Up to 100 mW (20 dBm) EIRP.

(3) 608-614 MHz band (channel 37). Up to 40 mW (16 dBm) EIRP.

(ii) Personal/Portable devices: Up to 100 mW (20 dBm) EIRP.

(4) 600 MHz duplex gap and guard bands. Up to 40 mW (16 dBm) EIRP.

(b) Technical limits—(1) Fixed white space devices. (i) Technical limits for fixed white space devices are shown in the table in paragraph (b)(1)(iii) of this section and subject to the requirements of this section.

(ii) For operation at EIRP levels of 36 dBm (4,000 mW) or less, fixed white space devices may operate at EIRP levels between the values shown in the table in paragraph (b)(1)(iii) of this section provided that the conducted power and the conducted power spectral density (PSD) limits are linearly interpolated between the values shown and the adjacent channel emission limit of the higher value shown in the table is met. Operation at EIRP levels above 36 dBm (4,000 mW) shall follow the requirements for 40 dBm (10,000 mW).

(iii) The conducted power spectral density from a fixed white space device shall not be greater than the values shown in the table in this paragraph (b)(1)(iii) when measured in any 100 kHz band during any time interval of continuous transmission.

Table 1 to Paragraph (b)(1)(iii)

EIRP
(6 MHz)
Conducted power limit
(6 MHz)
Conducted
PSD limit
(100 kHz)
(dBm)
Conducted
adjacent channel
emission limit
(100 kHz)
(dBm)
16 dBm (40 mW)10 dBm (10 mW)−7.4−62.8
20 dBm (100 mW)14 dBm (25 mW)−3.4−58.8
24 dBm (250 mW)18 dBm (63 mW)0.6−54.8
28 dBm (625 mW)22 dBm (158 mW)4.6−50.8
32 dBm (1,600 mW)26 dBm (400 mW)8.6−46.8
36 dBm (4,000 mW)30 dBm (1,000 mW)12.6−42.8
40 dBm (10,000 mW)30 dBm (1,000 mW)12.6−42.8

(2) Personal/portable white space devices. (i) Technical limits for personal/portable white space devices are shown in the table in paragraph (b)(2)(ii) of this section and subject to the requirements of this section.

(ii) The radiated power spectral density from a personal/portable white space device shall not be greater than the values shown in the table in this paragraph (b)(2)(ii) when measured in any 100 kHz band during any time interval of continuous transmission.

Table 2 to Paragraph (b)(2)(ii)

EIRP
(6 MHz)
Radiated PSD
limit EIRP
(100 kHz)
(dBm)
Radiated adjacent
channel emission
limit EIRP
(100 kHz)
(dBm)
16 dBm (40 mW)−1.4−56.8
20 dBm (100 mW)2.6−52.8

(3) Sensing-only devices. Sensing-only white space devices are limited to 17 dBm (50 mW) EIRP and are subject to the requirements of this paragraph and of §15.717 of this part.

(i) Radiated PSD limit: −0.4 dBm EIRP.

(ii) Adjacent channel emission limit: −55.8 dBm EIRP.

(c) Conducted power limits. (1) The conducted power, PSD and adjacent channel limits for fixed white space devices operating at up to 36 dBm (4000 milliwatts) EIRP shown in the table in paragraph (b)(1) of this section are based on a maximum transmitting antenna gain of 6 dBi. If transmitting antennas of directional gain greater than 6 dBi are used, the maximum conducted output power shall be reduced by the amount in dB that the directional gain of the antenna exceeds 6 dBi.

(2) The conducted power, PSD and adjacent channel limits for fixed white space devices operating at greater than 36 dBm (4000 milliwatts) EIRP shown in the table in paragraph (b)(1) of this section are based on a maximum transmitting antenna gain of 10 dBi. If transmitting antennas of directional gain greater than 10 dBi are used, the maximum conducted output power shall be reduced by the amount in dB that the directional gain of the antenna exceeds 10 dBi.

(3) Maximum conducted output power is the total transmit power over the occupied bandwidth delivered to all antennas and antenna elements averaged across all symbols in the signaling alphabet when the transmitter is operating at its maximum power level. Power must be summed across all antennas and antenna elements. The average must not include any time intervals during which the transmitter is off or is transmitting at a reduced power level. If multiple modes of operation are possible (e.g., alternative modulation methods), the maximum conducted output power is the highest total transmit power occurring in any mode.

(4) White space devices connected to the AC power line are required to comply with the conducted limits set forth in §15.207.

(d) Emission limits. (1) The adjacent channel emission limits shown in the tables in paragraphs (b)(1) and (2) of this section apply in the six megahertz channel immediately adjacent to each white space channel or group of contiguous white space channels in which the white space device is operating.

(2) At frequencies beyond the six megahertz channel immediately adjacent to each white space channel or group of contiguous white space channels in which the white space device is operating the white space device shall meet the requirements of §15.209.

(3) Emission measurements in the adjacent bands shall be performed using a minimum resolution bandwidth of 100 kHz with an average detector. A narrower resolution bandwidth may be employed near the band edge, when necessary, provided the measured energy is integrated to show the total power over 100 kHz.

(e) Transmit power control. White space devices shall incorporate transmit power control to limit their operating power to the minimum necessary for successful communication. Applicants for equipment certification shall include a description of the device's transmit power control feature mechanism.

(f) Security. White space devices shall incorporate adequate security measures to prevent the devices from accessing databases not approved by the FCC and to ensure that unauthorized parties cannot modify the device or configure its control features to operate in a manner inconsistent with the rules and protection criteria set forth in this subpart.

(g) Antenna requirements—(1) Fixed white space devices—(i) Above ground level. The transmit antenna height shall not exceed 100 meters above ground level in less congested areas or 30 meters above ground level in other areas, except that the antenna height may not exceed 10 meters above ground level in any area for fixed white space devices operating in the TV bands at 40 mW EIRP or less or operating across multiple contiguous TV channels at 100 mW EIRP or less.

(ii) Height above average terrain (HAAT). The transmit antenna shall not be located where the height above average terrain is more than 250 meters. The HAAT is to be calculated by the white space database using the methodology in §73.684(d) of this chapter.

(2) Personal/portable white space devices. Personal/portable devices shall have permanently attached transmit and receive antenna(s).

(3) Sensing-only white space devices operating under the provisions of §15.717 of this subpart. (i) The provisions of §15.204(c)(4) do not apply to an antenna used for transmission and reception/spectrum sensing.

(ii) Compliance testing for white space devices that incorporate a separate sensing antenna shall be performed using the lowest gain antenna for each type of antenna to be certified.

(h) Compliance with radio frequency exposure requirements—(1) Fixed white space devices. To ensure compliance with the Commission's radio frequency exposure requirements in §§1.1307(b), 2.1091 and 2.1093 of this chapter, fixed white space devices shall be accompanied by instructions on measures to take to ensure that persons maintain a distance of at least 40 cm from the device, as well as any necessary hardware that may be needed to implement that protection. These instructions shall be submitted with the application for certification.

(2) Personal/portable white space devices. Personal/portable white space devices that meet the definition of portable devices under §2.1093 of this chapter and that operate with a source-based time-averaged output of less than 20 mW will not be subject to routine evaluation for compliance with the radio frequency exposure guidelines in §§1.1307(b), 2.1091, and 2.1093 of this chapter, while devices that operate with a source-based time-average output power greater than 20 mW will be subject to the routine evaluation requirements.

[80 FR 73070, Nov. 23, 2015, as amended at 84 FR 34797, July 19, 2019]

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