Outdoor 6 GHz Wi-Fi in India: Why 36 dBm Telecom Power Would Repeat the 5 GHz Mess
On January 20, 2026, the Department of Telecommunications (DoT) published its Gazette notification of the Use of Low Power and Very Low Power Wireless Access System including Radio Local Area Network in Lower 6 GHz band (Exemption from Licensing Requirement) Rules, 2026. Consumer technology advocates and enterprise network architects were relieved. The rules open the 500 MHz contiguous block from 5925 MHz to 6425 MHz (the U-NII-5 band) to license-exempt use, which puts India alongside more than 96 countries that have unlocked the spectrum Wi-Fi 6E (IEEE 802.11ax) and Wi-Fi 7 (IEEE 802.11be) need.
The DoT also held out against years of heavy lobbying on power limits. Low Power Indoor (LPI) operation is capped at 30 dBm Equivalent Isotropically Radiated Power (EIRP) with a Power Spectral Density (PSD) limit of 11 dBm/MHz. Very Low Power (VLP) outdoor operation is capped at 14 dBm (25 mW) EIRP and 1 dBm/MHz PSD. These ceilings had one engineering goal: keep Wi-Fi 6E and Wi-Fi 7 signals inside homes and enterprise campuses, avoid outdoor radio pollution at scale, and protect incumbent fixed-satellite services (FSS).
COAI’s push for 36 dBm outdoor power in the lower 6 GHz band
Nine months later, that regulatory firewall is under pressure. In late October 2026, the Cellular Operators Association of India (COAI), which represents Reliance Jio, Bharti Airtel and Vodafone Idea, formally urged the DoT to notify Standard Power outdoor transmissions of 36 dBm EIRP (4 Watts) across the same delicensed 5925 to 6425 MHz band.
COAI Director General S.P. Kochhar pointed to recommendations from an expert committee chaired by Professor Radha Krishna Ganti of IIT Madras, which included telecom industry representatives and the Indian Space Research Organisation (ISRO). His argument was that 36 dBm outdoor Point-to-Multi-Point (P2MP) and Fixed Wireless Access (FWA) deployments are a practical, cost-effective way around Right-of-Way (RoW) bottlenecks and high fiber costs in rural and semi-urban India.
Anyone who has watched India’s unlicensed 5 GHz spectrum degrade over the past two years will recognize where this leads. Whatever the rural inclusion framing, the proposal sets up a tragedy of the commons. Reliance Jio has expanded Jio AirFiber on licensed 3.5 GHz (n78) and 26 GHz (n258) 5G spectrum, and increasingly through Unlicensed Band Radio (UBR) P2MP deployments. That hardware comes from its subsidiary Radisys and Mimosa Networks: the Mimosa A6 access points and the C6/C6x customer premises equipment (CPE). Bharti Airtel began its own UBR trials in November 2025 to test low-cost expansion in fiber-scarce pockets. But Jio’s dense urban and semi-urban UBR rollout has already turned the 5 GHz unlicensed band into an interference-ridden battleground.
Letting commercial operators put 36 dBm EIRP outdoor P2MP beams across the lower 6 GHz band without paying a rupee in auction fees, the consequences are easy to predict. Consumer Wi-Fi 6E and Wi-Fi 7 routers in millions of Indian homes get deafened, and the aggregate noise floor facing ISRO’s geostationary satellite uplinks goes up.
Why Jio wants 5925 to 6425 MHz at 36 dBm: the Mimosa A6 and C6 hardware
The urgency behind the October 2026 push makes sense once you look at the RF specifications of the equipment on Jio’s towers and subscriber rooftops. Serving heavy home broadband users on licensed 5G sub-6 GHz (n78) spectrum was eating into mobile capacity, and laying fiber to every standalone house ran into local municipal resistance. So Jio turned to Mimosa Networks, which its subsidiary Radisys acquired in 2023. The flagship P2MP hardware in these UBR rollouts is the Mimosa A6 sector access point on the tower and the Mimosa C6 or modular C6x outdoor unit (ODU) on the subscriber’s premises.
The RF front ends of the A6 and C6x, including their power amplifiers, synthesizers and internal filters, are engineered to run continuously across 5150 MHz to 6425 MHz. The A6 is an 8x8 Multi-User MIMO (MU-MIMO) outdoor sector radio with a 16 to 24 dBi adaptive beamforming antenna array (90-degree azimuth, 7-to-10-degree elevation beamwidth) and a maximum conducted output power of 24 to 29 dBm, built to reach the classic 36 dBm (4 Watt) EIRP ceiling. The client-side C6x is a 2x2 MIMO outdoor radio with up to 24 dBm conducted output power, paired with modular twist-on directional antennas from 12 to 25 dBi.
Until now, India allowed high-power outdoor unlicensed operation up to 36 dBm EIRP only in the upper 5 GHz band (specifically 5825 to 5875 MHz under the earlier WPC G.S.R. 45(E) exemptions, alongside the congested U-NII-1 and U-NII-3 allocations). Jio’s A6 and C6 units have therefore had to cram their wide 80 MHz and 160 MHz channels into legacy 5 GHz spectrum.
Meanwhile, a large share of the tuning range of the already-deployed hardware sits idle. The 500 MHz block from 5925 to 6425 MHz is locked out by firmware, because India’s January 2026 rules prohibit outdoor operation above 14 dBm EIRP and require integrated indoor antennas. If the DoT accepts COAI’s demand for 36 dBm Standard Power outdoors, operators can unlock 500 MHz of virgin spectrum on their existing tower hardware with an over-the-air firmware change, skipping spectrum auctions entirely.
How Jio AirFiber UBR degrades 5 GHz Wi-Fi and FWA performance
Before the 6 GHz band goes to high-power outdoor commercial FWA, regulators should look at what Jio AirFiber’s UBR deployments have already done to 5 GHz. Field reports and technical breakdowns of the C6 and A6 deployments show that running Wi-Fi-derived protocols for macro-scale, multi-user outdoor broadband creates MAC-layer and PHY-layer bottlenecks. They hurt the operator’s own subscribers and every independent Wi-Fi network nearby.
In many initial and ongoing UBR deployments, the Mimosa A6/C6 ecosystem has run in legacy Wi-Fi Interop mode, or on early firmware that behaves much like IEEE 802.11ac (Wi-Fi 5). That means standard Orthogonal Frequency Division Multiplexing (OFDM) and downlink-only MU-MIMO, without fully active uplink Orthogonal Frequency Division Multiple Access (OFDMA) or strict GPS-synchronized Time Division Multiple Access (TDMA) framing across all sectors. In standard OFDM, the whole 80 MHz or 160 MHz channel goes to one transmitting station in any given symbol period. The A6 can use 8x8 downlink MU-MIMO to beamform data to several C6 clients at once during downloads, but the uplink becomes a heavy contention bottleneck.
Suppose 50 to 150 residential subscribers on one A6 sector upload at the same time, through cloud backups, Zoom calls, CCTV streams or online gaming. Without uplink MU-MIMO or active UL-OFDMA resource unit (RU) scheduling, the C6 client radios cannot transmit concurrently. They fall back on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), or contended timeslots, and each rooftop unit waits for the medium to clear.
The C6 radios are also mounted outdoors and aimed across hundreds of meters at a tower, which makes them classic hidden nodes to one another. Client A on a rooftop in SectorNorth cannot hear Client B on a rooftop 800 meters away in SectorSouth, even though both transmit to the same A6 sector antenna. When both transmit at once, their packets collide at the A6 receiver. The result is exponential random backoff, retransmissions, heavy jitter, and upload speeds that routinely fall below 10 Mbps on 100 Mbps plans during peak evening hours.
Now consider the people in apartment buildings along the path of that A6 beam. An indoor Wi-Fi router at 20 to 23 dBm EIRP depends on Listen-Before-Talk (LBT) Energy Detect (ED) and Preamble Detect (PD) thresholds, typically -62 dBm for energy detection and -82 dBm for valid 802.11 preambles over a 20 MHz channel. A tower-mounted UBR sector antenna at 36 dBm EIRP, or a neighbor’s rooftop C6x firing a directional 36 dBm beam across the street, easily punches through glass windows and brick walls. Inside the surrounding apartments it arrives at -65 to -75 dBm or stronger.
The indoor consumer router and the outdoor UBR system share the same 802.11 preamble structure and unlicensed channels. So the router’s Clear Channel Assessment (CCA) state machine keeps declaring the medium BUSY, and the router defers its own transmissions for milliseconds at a time while a tower serving 150 households half a kilometer away finishes its downlink bursts. The Mimosa A6/C6x stack may use Wi-Fi 6E OFDMA with 2 MHz Resource Units (RUs) or proprietary TDMA framing to resist narrowband noise in its own network. Even so, its high-power 80 MHz or 160 MHz outdoor transmissions act as a persistent wide-swath jammer for indoor consumer access points, which have to obey strict LBT contention rules.
Link budget analysis: how 36 dBm outdoor power breaks indoor Wi-Fi 6E and Wi-Fi 7
The lower 6 GHz band (5925 to 6425 MHz) is especially exposed to outdoor high-power domination because of its channel plan. The 500 MHz block holds twenty-four 20 MHz channels, twelve 40 MHz channels, six 80 MHz channels, three 160 MHz channels and only one contiguous 320 MHz channel. The value of Wi-Fi 6E and Wi-Fi 7 to devices like the Sony PlayStation 5 Pro, Apple Vision Pro, Meta Ray-Ban smart glasses and multi-gigabit enterprise laptops depends on clean, low-latency 160 MHz and 320 MHz channels that can sustain 1024-QAM (Wi-Fi 6E) and 4096-QAM (Wi-Fi 7).
Reaching 4096-QAM takes a Signal-to-Interference-plus-Noise Ratio (SINR) of roughly 35 to 38 dB. 1024-QAM needs roughly 29 to 32 dB. Under the DoT’s January 2026 rules, physics preserves that SINR in two ways:
Low Power Indoor (LPI) devices are capped at 30 dBm EIRP (11 dBm/MHz PSD), must use integrated antennas, cannot run on battery power and are confined indoors. At least two exterior building walls, adding 30 to 40 dB of penetration loss, separate one home’s router from a neighbor’s router across the street.
Very Low Power (VLP) outdoor devices, such as a smartphone tethering to AR glasses, are capped at 14 dBm EIRP (25 mW, 1 dBm/MHz PSD).
Authorizing Standard Power (SP) outdoor operation at 36 dBm EIRP (4,000 mW) creates a 160-fold power asymmetry (+22 dB) over VLP outdoor devices and a 4-fold advantage (+6 dB) over indoor routers. The catch is that the 36 dBm transmitter sits outside on a high mast with a clear Line-of-Sight (LoS) to every window in the neighborhood.
To model the Electromagnetic Compatibility (EMC) and link budget impact on an indoor Wi-Fi 7 network, I used free-space path loss (the ITU-R P.1411 line-of-sight baseline), a fixed window ingress loss and 802.11be SINR thresholds. The Python script below calculates the interference power that a single 36 dBm outdoor UBR sector antenna delivers into an urban apartment at various distances. It then works out the SINR for an indoor Wi-Fi 7 client sitting 6 meters from its LPI home router and checks whether 4096-QAM, 1024-QAM or basic CCA contention survives.
import numpy as np
def fspl_db(freq_mhz: float, dist_m: float) -> float:
"""Calculate Free Space Path Loss (FSPL) in dB."""
return 20 * np.log10(dist_m) + 20 * np.log10(freq_mhz) - 27.55
def analyze_6ghz_ubr_interference():
# Operating Parameters in Lower 6 GHz (Center of U-NII-5: 6175 MHz, 160 MHz Channel)
freq_mhz = 6175.0
bw_mhz = 160.0
# Thermal Noise Floor for 160 MHz channel with 7 dB Receiver Noise Figure (NF)
# N = -174 dBm/Hz + 10*log10(BW_Hz) + NF
thermal_noise_dbm = -174.0 + 10 * np.log10(bw_mhz * 1e6) + 7.0 # ~ -84.96 dBm
# Indoor Consumer Wi-Fi 7 LPI Link (Compliant with Jan 2026 DoT Gazette)
# PSD limit = 11 dBm/MHz -> Max EIRP at 160 MHz is capped at 30 dBm total
lpi_tx_eirp_dbm = 27.0 # Typical multi-stream consumer router EIRP in 160 MHz
client_dist_m = 6.0 # Client device in living room 6m from router (1 interior wall = 6 dB)
indoor_path_loss_db = fspl_db(freq_mhz, client_dist_m) + 6.0
desired_signal_dbm = lpi_tx_eirp_dbm - indoor_path_loss_db # ~ -42.8 dBm
# Outdoor Commercial UBR (Mimosa A6 / P2MP Sector at COAI Proposed Standard Power)
ubr_eirp_dbm = 36.0 # 4 Watts EIRP proposed by COAI
window_glass_loss_db = 8.0 # Standard non-coated apartment window/balcony ingress loss
# 802.11be (Wi-Fi 7) Thresholds for 160 MHz
cca_ed_threshold_dbm = -62.0 # Energy Detect busy threshold
cca_pd_threshold_dbm = -73.0 # Preamble Detect threshold scaled for 160 MHz
print("--- 6 GHz (6175 MHz, 160 MHz BW) Indoor vs. Outdoor UBR Interference Model ---")
print(f"Thermal Noise Floor (160 MHz) : {thermal_noise_dbm:.2f} dBm")
print(f"Desired Indoor LPI Signal (S) : {desired_signal_dbm:.2f} dBm (at {client_dist_m}m)")
print(f"Baseline Indoor SNR (No UBR) : {desired_signal_dbm - thermal_noise_dbm:.2f} dB (Supports 4096-QAM)\n")
print(f"{'UBR Dist (m)':<14} | {'Ingress I (dBm)':<17} | {'Noise rise (dB)':<16} | {'Resulting SINR (dB)':<20} | {'Operational Impact'}")
print("-" * 110)
for dist in [35, 75, 150, 300, 500]:
outdoor_loss_db = fspl_db(freq_mhz, dist)
ingress_interference_dbm = ubr_eirp_dbm - outdoor_loss_db - window_glass_loss_db
# Convert to linear mW to sum Thermal Noise + Interference
noise_mw = 10 ** (thermal_noise_dbm / 10.0)
interf_mw = 10 ** (ingress_interference_dbm / 10.0)
noise_rise_db = 10 * np.log10((noise_mw + interf_mw) / noise_mw)
sinr_db = desired_signal_dbm - 10 * np.log10(noise_mw + interf_mw)
if ingress_interference_dbm >= cca_ed_threshold_dbm:
impact = "CCA Energy Detect LOCKOUT (Channel unusable)"
elif ingress_interference_dbm >= cca_pd_threshold_dbm:
impact = "CCA Preamble Deferral + Loss of 4096/1024-QAM"
elif sinr_db < 35.0:
impact = "4096-QAM Degraded"
else:
impact = "Coexistence Possible (Minimal MCS drop)"
print(f"{dist:<14} | {ingress_interference_dbm:<17.2f} | {noise_rise_db:<16.1f} | {sinr_db:<20.2f} | {impact}")
if __name__ == "__main__":
analyze_6ghz_ubr_interference()The results explain why independent telecom analyst Parag Kar warned that high-power commercial deployments would dominate the band and make it useless for homes and enterprises:
--- 6 GHz (6175 MHz, 160 MHz BW) Indoor vs. Outdoor UBR Interference Model ---
Thermal Noise Floor (160 MHz) : -84.96 dBm
Desired Indoor LPI Signal (S) : -42.83 dBm (at 6.0m)
Baseline Indoor SNR (No UBR) : 42.13 dB (Supports 4096-QAM)
UBR Dist (m) | Ingress I (dBm) | Noise rise (dB) | Resulting SINR (dB) | Operational Impact
--------------------------------------------------------------------------------------------------------------
35 | -51.14 | 33.8 | 8.32 | CCA Energy Detect LOCKOUT (Channel unusable)
75 | -57.76 | 27.2 | 14.93 | CCA Energy Detect LOCKOUT (Channel unusable)
150 | -63.78 | 21.2 | 20.93 | CCA Preamble Deferral + Loss of 4096/1024-QAM
300 | -69.81 | 15.3 | 26.85 | CCA Preamble Deferral + Loss of 4096/1024-QAM
500 | -74.24 | 11.1 | 31.06 | 4096-QAM DegradedLook at 300 meters, a completely standard cell radius for an urban or semi-urban FWA deployment. A single 36 dBm UBR beam arrives inside the apartment at -69.81 dBm even after passing through a window. That one outdoor link raises the effective noise floor by 15.3 dB, triggers 802.11 Preamble Detection deferral across the whole 160 MHz channel, and drops indoor SINR from 42.13 dB to 26.85 dB. That is below the 29 to 32 dB that 1024-QAM needs, so Wi-Fi 7’s 4096-QAM is gone and Wi-Fi 6E’s 1024-QAM goes with it.
Even at 500 meters the indoor SINR falls to 31.06 dB, which is enough to lose 4096-QAM while leaving 1024-QAM marginally intact. Within 75 meters of the sector antenna or of an adjacent rooftop’s C6x client radio, indoor interference exceeds -58 dBm. That crosses the -62 dBm Energy Detect threshold and locks out the indoor router whenever the outdoor sector transmits. At 35 meters the noise floor rises by 33.8 dB. A typical 3-sector or 4-sector tower uses all three 160 MHz channels in the lower 6 GHz band to avoid self-interference between its own sectors, so no clean spectrum remains in 5925 to 6425 MHz for the apartment residents below to switch to.
ISRO’s satellite problem: aggregate interference in the C-band uplink
Consumer Wi-Fi degradation is a local link-budget problem. The reason the DoT has hesitated since July 2026 to approve the IIT Madras committee’s 36 dBm recommendation is a bigger one, raised by ISRO and rooted in orbital physics. The 5925 to 6425 MHz band is not empty real estate. It is the primary commercial and strategic Extended C-band and Standard C-band Earth-to-Space (uplink) allocation for Geostationary Orbit (GSO) satellites 35,786 kilometers above the equator.
Terrestrial wireless circles often assume satellite interference is a local issue around ISRO earth stations, so you could draw an exclusion zone around a master control facility in Hassan or Bhopal and transmit at 36 dBm everywhere else. That logic holds only for Space-to-Earth (downlink) bands, where the victim receiver is a dish on the ground. In the 5925 to 6425 MHz Earth-to-Space uplink band, the victim receiver is the satellite transponder itself, whose footprint covers the entire Indian subcontinent at once.
A geostationary satellite receiver cannot be protected by terrestrial exclusion zones, because its uplink antenna beam integrates every milliwatt radiated skyward across India. Under ITU-R Recommendation SF.1006 and standard satellite protection criteria, the aggregate interference power (I_agg) from all unlicensed devices in its footprint must not raise the satellite’s effective thermal noise floor (N = k T_s B) by more than a small fraction. The usual ΔT/T threshold is 1% to 6%, which corresponds to an Interference-to-Noise ratio (I/N) of -20 dB to -12.2 dB.
ISRO tolerated Low Power Indoor (30 dBm) and Very Low Power outdoor (14 dBm) devices in January 2026 but objected to Standard Power (36 dBm) outdoor FWA for three compounding reasons:
No building clutter or roof attenuation. An indoor LPI router radiating skyward above a 20-degree elevation angle passes through concrete ceiling slabs and neighboring multi-story buildings, which add 17 to 30 dB of building entry/exit loss (ITU-R P.2109), plus body loss and polarization mismatch. An outdoor tower-mounted A6 sector antenna or a rooftop C6x client radio sits clear of building roofs with 0 dB of clutter shielding.
Up-tilted CPE beams and grating lobes. A tower sector antenna is tilted down by 3 to 7 degrees, mechanically or electronically. The subscriber rooftop CPE (the Mimosa C6/C6x) is mounted on a 1-to-3-story house and tilted upward toward a 30-to-40-meter telecom tower. A subscriber within a few hundred meters of a tall tower points a directional 36 dBm main lobe, plus strong upper sidelobes and ground-reflection specular lobes, above the horizon toward the geostationary arc, which sits at elevation angles of 45 to 75 degrees across India.
High duty cycle. Studies of consumer indoor Wi-Fi assume an activity factor of roughly 0.4% to 2% across millions of mostly idle home routers, with only a tiny share active at any microsecond. A commercial telecom P2MP sector carrying traffic for 100 households, 24/7 IPTV set-top boxes and enterprise leased lines runs at a sustained duty cycle of 40% to 80% during peak hours.
The script below quantifies the orbital risk. It computes the aggregate interference-to-noise ratio (I/N) at an ISRO GSO satellite transponder (T_s = 550 K, G/T = -1.5 dB/K) over India. The comparison is 10 million indoor LPI routers against just 250,000 outdoor 36 dBm UBR nodes (50,000 tower sectors and 200,000 active rooftop CPEs transmitting concurrently) across a 36 MHz satellite transponder bandwidth. The UBR scenario assumes a 35% duty cycle.
import numpy as np
def calculate_isro_gso_uplink_interference():
# Geostationary Satellite Parameters (6175 MHz Uplink, 36 MHz Transponder)
freq_hz = 6.175e9
c = 3e8
wavelength = c / freq_hz
slant_range_m = 37500e3 # ~37,500 km slant range from India to GSO slot
bw_hz = 36e6 # Standard 36 MHz C-band satellite transponder
k_boltzmann = 1.380649e-23
sat_rx_gain_dbi = 30.0 # Contoured India beam uplink receive antenna gain
sat_sys_temp_k = 550.0 # Satellite receiver noise temperature (K)
# Satellite Thermal Noise Power (N = k * T * B) in dBm
sat_noise_watts = k_boltzmann * sat_sys_temp_k * bw_hz
sat_noise_dbm = 10 * np.log10(sat_noise_watts) + 30.0 # ~ -95.63 dBm
# Free Space Path Loss to Geostationary Orbit + Atmospheric Loss (0.5 dB)
fspl_gso_db = 20 * np.log10(4 * np.pi * slant_range_m / wavelength) + 0.5 # ~ 200.24 dB
# Protection Criterion: Delta T / T <= 6% --> Max allowable I/N = -12.22 dB
max_allowable_i_dbm = sat_noise_dbm - 12.22 # ~ -107.85 dBm
# Scenario A: 10,000,000 Indoor LPI Routers across India (Jan 2026 Rules)
# 11 dBm/MHz PSD -> 26.5 dBm in 36 MHz, Duty cycle = 1.0%, Avg Skyward Gain = -5 dBi (off-axis),
# Building Ceiling/Clutter Loss = 20 dB, Polarization Loss = 3 dB
n_lpi = 10_000_000
lpi_duty = 0.01
lpi_single_sky_eirp_dbm = 26.5 - 5.0 - 20.0 - 3.0 # -1.5 dBm effective skyward per active unit
lpi_agg_rx_dbm = (lpi_single_sky_eirp_dbm + 10 * np.log10(n_lpi * lpi_duty)
- fspl_gso_db + sat_rx_gain_dbi)
lpi_i_over_n_db = lpi_agg_rx_dbm - sat_noise_dbm
# Scenario B: Commercial Outdoor UBR at 36 dBm EIRP
# 250,000 radios (50,000 tower sectors + 200,000 active rooftop CPEs) across a 36 MHz channel
# 36 dBm EIRP, High FWA Duty Cycle = 35%, 0 dB Building Loss,
# Avg Skyward Sidelobe / Up-tilted CPE Scatter Gain = -6 dB relative to peak EIRP, Pol Loss = 1.5 dB
n_ubr = 250_000
ubr_duty = 0.35
ubr_single_sky_eirp_dbm = 36.0 - 6.0 - 1.5 # 28.5 dBm effective skyward per active unit
ubr_agg_rx_dbm = (ubr_single_sky_eirp_dbm + 10 * np.log10(n_ubr * ubr_duty)
- fspl_gso_db + sat_rx_gain_dbi)
ubr_i_over_n_db = ubr_agg_rx_dbm - sat_noise_dbm
# Delta T / T equals I/N in linear terms
ubr_dt_over_t_pct = 100 * 10 ** (ubr_i_over_n_db / 10)
lpi_dt_over_t_pct = 100 * 10 ** (lpi_i_over_n_db / 10)
breach_margin_db = ubr_i_over_n_db - (-12.22)
print("--- ISRO GSO C-Band Uplink (6175 MHz, 36 MHz Transponder) Aggregate I/N Analysis ---")
print(f"Satellite Thermal Noise (N) : {sat_noise_dbm:.2f} dBm")
print(f"ITU 6% Delta-T/T Threshold (I_max) : {max_allowable_i_dbm:.2f} dBm (I/N = -12.22 dB)\n")
print(f"Scenario A (10M Indoor LPI Routers) : I_agg = {lpi_agg_rx_dbm:.2f} dBm | I/N = {lpi_i_over_n_db:+.2f} dB | dT/T = {lpi_dt_over_t_pct:.2f}% [SAFE]")
print(f"Scenario B (250k Outdoor 36 dBm UBR) : I_agg = {ubr_agg_rx_dbm:.2f} dBm | I/N = {ubr_i_over_n_db:+.2f} dB | dT/T = {ubr_dt_over_t_pct:.0f}% [BREACH]")
print(f"Excess Interference from Outdoor UBR : {ubr_agg_rx_dbm - lpi_agg_rx_dbm:+.2f} dB higher than 10M indoor routers")
print(f"Margin over the -12.22 dB threshold : {breach_margin_db:+.2f} dB")
if __name__ == "__main__":
calculate_isro_gso_uplink_interference()The resulting orbital link budget:
--- ISRO GSO C-Band Uplink (6175 MHz, 36 MHz Transponder) Aggregate I/N Analysis ---
Satellite Thermal Noise (N) : -95.63 dBm
ITU 6% Delta-T/T Threshold (I_max) : -107.85 dBm (I/N = -12.22 dB)
Scenario A (10M Indoor LPI Routers) : I_agg = -121.74 dBm | I/N = -26.10 dB | dT/T = 0.25% [SAFE]
Scenario B (250k Outdoor 36 dBm UBR) : I_agg = -92.32 dBm | I/N = +3.32 dB | dT/T = 215% [BREACH]
Excess Interference from Outdoor UBR : +29.42 dB higher than 10M indoor routers
Margin over the -12.22 dB threshold : +15.54 dBOne outdoor 36 dBm UBR radio with no roof attenuation puts 1,000 times (+30 dB) more skyward RF energy into the sky per active millisecond than an indoor LPI router behind a concrete ceiling. A nationwide deployment of just 250,000 outdoor 36 dBm UBR radios on a 36 MHz swath produces 29.42 dB more aggregate interference at ISRO’s satellite receiver than 10 million indoor consumer routers. The outdoor fleet’s aggregate I/N lands at +3.32 dB, which breaches the ITU -12.22 dB protection threshold by more than 15 dB. In ΔT/T terms, the 10 million indoor routers add about 0.25% to the transponder’s noise temperature, well inside the limit, while the outdoor fleet adds roughly 215%, more than tripling it.
Why automated frequency coordination (AFC) cannot fix this in India
Whenever analysts raise the interference risk of 36 dBm outdoor operation in the 6 GHz band, lobbyists point to the United States and Canada. There the FCC and ISED permit 36 dBm EIRP Standard Power outdoor operation under Automated Frequency Coordination (AFC), and the Mimosa A6 datasheet advertises the radio as “AFC-Ready for U.S. Deployments.” Treating AFC as a turnkey answer for India overlooks how AFC works and what it cannot protect.
First, an AFC system is a centralized geolocation database that protects terrestrial Point-to-Point (P2P) Fixed Service microwave links, such as utility, railway and backhaul dishes. It queries an accurate national registry of fixed microwave receivers, like the FCC’s Universal Licensing System (ULS). It computes path loss from the outdoor AP’s GPS coordinates and antenna height using terrain and clutter models (ITM, Winner II), then denies channels where predicted interference at a microwave dish exceeds an I/N of -6 dB.
India does not publish terrestrial microwave links and Department of Space/ISRO assignments in an open, geocoded, public API equivalent to the FCC’s ULS, and the WPC has not deployed a live, certified AFC operator framework. AFC also only calculates point-to-point exclusion zones for terrestrial dishes. A geographic database cannot route around a geostationary satellite uplink beam that covers all of India’s landmass. Protecting a GSO uplink with terrestrial rules alone would mean strict antenna elevation mask limits, such as the FCC’s cap of 21 dBm EIRP above a 30-degree elevation angle on outdoor APs, plus a ban on skyward-tilted client links. That restriction breaks when high-gain rooftop C6x antennas are aimed up at tall urban cell towers or reflect off wet monsoon rooftops.
Second, AFC has no visibility into unlicensed indoor Wi-Fi routers. An AFC database will authorize a Jio or Airtel tower to blast 36 dBm across all three 160 MHz channels in a dense residential colony in Bengaluru, Pune or Kolkata, provided no licensed terrestrial microwave link is nearby. It is not programmed to care that 2,000 apartments within 400 meters of that tower just had their Wi-Fi 6E and Wi-Fi 7 noise floors raised by 15 to 25 dB.
The verdict: keep commercial FWA on licensed spectrum
COAI’s position on the 6 GHz band carries some irony. For years, cellular operators lobbied to reserve the entire 1,200 MHz of the 6 GHz band (5925 to 7125 MHz) for licensed International Mobile Telecommunications (IMT / 5G Advanced and 6G), arguing that Wi-Fi did not need the spectrum. The Government of India reached a compromise in the National Frequency Allocation Plan (NFAP). It reserved the upper 700 MHz (6425 to 7125 MHz) for licensed mobile/IMT services and delicensed only the lower 500 MHz (5925 to 6425 MHz) for indoor and very-low-power Wi-Fi.
Operators already hold 700 MHz of upper 6 GHz for future licensed networks, on top of large holdings in the 3.5 GHz (n78) and 26 GHz (n258) bands acquired to deliver 5G and Fixed Wireless Access. Now they want the 500 MHz Wi-Fi commons too. Running commercial, subscription-based P2MP broadband at 36 dBm on delicensed spectrum lets giant operators push infrastructure costs onto the public airwaves. They could invest in Fiber-to-the-Home (FTTH), or deploy FWA on their auctioned 3.5 GHz and 26 GHz spectrum, where 3GPP 5G NR protocols schedule interference deterministically. UBR lets them flood unlicensed bands with high-power outdoor carriers instead, degrading the indoor Wi-Fi routers that carry over 70% of India’s indoor internet traffic.
An operator that wants to deliver high-power outdoor Fixed Wireless Access over hundreds of meters should do it on licensed spectrum. There, spectrum usage charges are paid, base stations are coordinated, and responsibility for interference is clear. The DoT and WPC got the physics right on January 20, 2026, when they capped the 5925 to 6425 MHz band at 30 dBm indoors and 14 dBm outdoors. Giving in to the 36 dBm outdoor lobby now would do little for the rural digital divide. It would export the congestion, upload bottlenecks and RF pollution of the 5 GHz band into the only clean wideband Wi-Fi spectrum India has left.
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