#### § 24.237 Interference protection.

(a) All licensees are required to coordinate their frequency usage with the co-channel or adjacent channel incumbent fixed microwave licensees in the 1850-1990 MHz band. Coordination must occur before initiating operations from any base station. Problems that arise during the coordination process are to be resolved by the parties to the coordination. Licensees are required to coordinate with all users possibly affected, as determined by appendix I to this subpart E (Appendix E of the Memorandum Opinion and Order, GEN Docket No. 90-314, FCC 94-144; TIA Telecommunications Systems Bulletin 10-F, “Interference Criteria for Microwave Systems,” May 1994, (TSB10-F)); or an alternative method agreed to by the parties.

(b) The results of the coordination process need to be reported to the Commission only if the parties fail to agree. Because broadband PCS licensees are required to protect fixed microwave licensees in the 1850-1990 MHz band, the Commission will be involved in the coordination process only upon complaint of interference from a fixed microwave licensee. In such a case, the Commission will resolve the issues.

(c) In all other respects, coordination procedures are to follow the requirements of [§ 101.103(d) of this chapter](/on/2024-09-20/title-47/section-101.103#p-101.103(d)) to the extent that these requirements are not inconsistent with those specified in this part.

(d) The licensee must perform an engineering analysis to assure that the proposed facilities will not cause interference to existing OFS stations within the coordination distance specified in Table 3 of a magnitude greater than that specified in the criteria set forth in [paragraphs (e)](/on/2024-09-20/title-47/section-24.237#p-24.237(e)) and [(f)](/on/2024-09-20/title-47/section-24.237#p-24.237(f)) of this section, unless there is prior agreement with the affected OFS licensee. Interference calculations shall be based on the sum of the power received at the terminals of each microwave receiver from all of the applicant's current and proposed PCS operations.

Table 3—Coordination Distances in Kilometers

| PCS Base Station Antenna HAAT in Meters | | | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| EIRP(W) | 5 | 10 | 20 | 50 | 100 | 150 | 200 | 250 | 300 | 500 | 1000 | 1500 | 2000 |
| 0.1 | 90 | 93 | 99 | 110 | 122 | 131 | 139 | 146 | 152 | 173 | 210 | 239 | 263 |
| 0.5 | 96 | 100 | 105 | 116 | 128 | 137 | 145 | 152 | 158 | 179 | 216 | 245 | 269 |
| 1 | 99 | 103 | 108 | 119 | 131 | 140 | 148 | 155 | 161 | 182 | 219 | 248 | 272 |
| 2 | 120 | 122 | 126 | 133 | 142 | 148 | 154 | 159 | 164 | 184 | 222 | 250 | 274 |
| 5 | 154 | 157 | 161 | 168 | 177 | 183 | 189 | 194 | 198 | 213 | 241 | 263 | 282 |
| 10 | 180 | 183 | 187 | 194 | 203 | 210 | 215 | 220 | 225 | 240 | 268 | 291 | 310 |
| 20 | 206 | 209 | 213 | 221 | 229 | 236 | 242 | 247 | 251 | 267 | 296 | 318 | 337 |
| 50 | 241 | 244 | 248 | 255 | 264 | 271 | 277 | 282 | 287 | 302 | 331 | 354 | 374 |
| 100 | 267 | 270 | 274 | 282 | 291 | 297 | 303 | 308 | 313 | 329 | 358 | 382 | 401 |
| 200 | 293 | 296 | 300 | 308 | 317 | 324 | 330 | 335 | 340 | 356 | 386 | 409 | 436 |
| 500 | 328 | 331 | 335 | 343 | 352 | 359 | 365 | 370 | 375 | 391 | 421 | 440 | |
| 1000 | 354 | 357 | 361 | 369 | 378 | 385 | 391 | 397 | 402 | 418 | | | |
| 1200 | 361 | 364 | 368 | 376 | 385 | 392 | 398 | 404 | 409 | 425 | | | |
| 1640 | 372 | 375 | 379 | 388 | 397 | 404 | 410 | 416 | 421 | 437 | | | |
| 2400 | 384 | 387 | 391 | 399 | 408 | 415 | 423 | 427 | 431 | | | | |
| 3280 | 396 | 399 | 403 | 412 | 419 | 427 | 435 | 439 | 446 | | | | |

(e) For microwave paths of 25 kilometers or less, interference determinations shall be based on the C/I criteria set forth in TIA Telecommunications Systems Bulletin 10-F, “Interference Criteria for Microwave Systems,” May 1994 (TSB10-F).

(f) For microwave paths longer than 25 kilometers, the interference protection criterion shall be such that the interfering signal will not produce more than 1.0 dB degradation of the practical threshold of the microwave receiver for analog system, or such that the interfering signal will not cause an increase in the bit error rate (BER) from 10E-6 to 10E-5 for digital systems.

(g) The development of the C/I ratios and interference criteria specified in [paragraphs (e)](/on/2024-09-20/title-47/section-24.237#p-24.237(e)) and [(f)](/on/2024-09-20/title-47/section-24.237#p-24.237(f)) of this section and the methods employed to compute the interfering power at the microwave receivers shall follow generally acceptable good engineering practices. The procedures described for computing interfering signal levels in (appendix I to this subpart E Appendix E of the Memorandum Opinion and Order, GEN Docket No. 90-314, FCC 94-144) shall be applied. Alternatively, procedures for determining interfering signal levels and other criteria as may be developed by the Electronics Industries Association (EIA), the Institute of Electrical and Electronics Engineers, Inc. (IEEE), the American National Standards Institute (ANSI) or any other recognized authority will be acceptable to the Commission.

[[59 FR 32854](https://www.federalregister.gov/citation/59-FR-32854), June 24, 1994, as amended at [61 FR 29691](https://www.federalregister.gov/citation/61-FR-29691), June 21, 1996; [69 FR 75171](https://www.federalregister.gov/citation/69-FR-75171), Dec. 15, 2004]