47 CFR § 15.709 - General technical requirements.

§ 15.709 General technical requirements.
Link to an amendment published at 86 FR 2291, Jan. 12, 2021.

(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)(A) Fixed devices in the TV bands below 602 MHz: Up to 4 W (36 dBm) EIRP, and up to 16 W (42 dBm) EIRP in less congested areas. Fixed devices in the 602-608 MHz band may operate with up to 4 W (36 dBm) EIRP.

(B) Fixed devices in the 600 MHz service bands above 620 MHz: Up to 4 W (36 dBm) EIRP, and up to 10 W (40 dBm) EIRP in less congested areas. Fixed devices that operate in any portion of the 614-620 MHz band may operate with up to 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.

(5) Mobile devices in the TV bands below 602 MHz. Up to 16 W (42 dBm) EIRP in less congested areas. Mobile device operation is not permitted above 602 MHz. Mobile devices may operate only in less congested areas.

(b) Technical limits -

(1) Fixed and mobile white space devices.

(i) Technical limits for fixed and mobile 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 and mobile 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) but not greater than 40 dBm (10,000 mW) shall follow the requirements for 40 dBm (10,000 mW). Operation at EIRP levels above 40 dBm (10,000 mW) shall follow the requirements for 42 dBm (16,000 mW).

(iii) The conducted power spectral density from a fixed or mobile 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 kilohertz 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 1
(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 (1,0000 mW) 30 dBm (1,000 mW) 12.6 −42.8
42 dBm (16,000 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.

(4) Narrowband white space devices.

(i) A narrowband white space device that operates as a client must communicate with a master device (fixed, Mode II, mobile or narrowband) that contacts the white space database to obtain a list of available channels and operating powers at its location. A narrowband white space device that acts as a master must incorporate a geo-location mechanism and be capable of obtaining lists of available channels and operating powers from the white space database.

(ii) Narrowband white space devices shall operate on channel sizes that are no more than 100 kilohertz. The edge of a narrowband channel shall be offset from the upper and lower edge of the 6 megahertz channel in which it operates by at least 250 kilohertz, except in the case where bonded 6 megahertz channels share a common band edge. Narrowband operating channels shall be at integral multiples of 100 kilohertz beginning at a 250 kilohertz offset from a 6 megahertz channel's edge, or with no offset at the common band edge of two bonded 6 megahertz channels.

(iii) The conducted power limit is 12.6 dBm in a 100 kilohertz segment. The EIRP limit is 18.6 dBm in a 100 kilohertz segment. The conducted power spectral density limit is 12.6 dBm in any 100 kilohertz band during any time interval of continuous transmission.

(iv) Conducted adjacent channel emissions shall be limited to −42.8 dBm in 100 kilohertz in a first adjacent 6 megahertz channel, starting at the edge of the 6 megahertz channel within which the narrowband device is operating. This limit shall not apply between the edge of the narrowband channel and the edge of the 6 megahertz channel that contains it.

(v) If transmitting antennas of directional gain greater than 6 dBi are used, the maximum conducted power output shall be reduced by the amount in dB that the directional gain of the antenna exceeds 6 dBi.

(vi) Total occupancy for each narrowband channel shall be limited to 36 seconds per hour.

(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 and mobile white space devices operating at greater than 36 dBm (4,000 milliwatts) EIRP shown in the table in paragraph (b)(1)(iii) of this section are based on a maximum transmitting antenna gain of 12 dBi. If transmitting antennas of directional gain greater than 12 dBi are used, the maximum conducted output power shall be reduced by the amount in dB that the directional gain of the antenna exceeds 12 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 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. White space devices shall ensure compliance with the Commission's radio frequency exposure requirements in §§ 1.1307(b), 2.1091 and 2.1093 of this chapter, as appropriate. Applications for equipment authorization of RF sources under this section must contain a statement confirming compliance with these requirements. Technical information showing the basis for this statement must be submitted to the Commission upon request.

[80 FR 73070, Nov. 23, 2015, as amended at 84 FR 34797, July 19, 2019; 85 FR 18149, Apr. 1, 2020; 86 FR 2291, Jan. 12, 2021]
Editorial Note:
At 86 FR 2291, Jan. 12, 2021, paragraph (g)(1)(ii) was revised. The revision was delayed indefinitely.