The document discusses external interference affecting microwave links in Bangladesh. It provides data showing up to 37.7% yearly outage trends for some links. The 7-8 GHz frequency bands were most affected, with specific links named. Case studies describe interference locations, frequencies used, and receive signal levels both with and without interference. Using the same frequency at unknown neighboring links can cause issues like threshold degradation, errors, and downtime, hampering quality and growth for both operators. Coordination is needed to reuse frequencies without interference and maintain network objectives.

1. External Interference & It’s impact on TX network

2. Most vulnerable time for HCMW Another vulnerable time for HCMW Yearly HCMW Outage Trend

4. Nationwide major affected areas Affected freq.band: 7GHz & 8 GHz Sadar Thakurgaon Dumki Patuakhali Sadar Panchagarh Sadar Mymensingh Sadar Meherpur Sadar Jessore Sadar Gazipur Khanshama Dinajpur Debidar Comilla Sarail Brahmanbaria Sadar Bogra Nolchiti Barisal Thana District

5. Probable interference affected link Total 54 SDH links across the country suspected to be affected by external interference & unusual outage Scenario in 2009 8 Sylhet 4 Bogra 9 Khulna 18 Chittagong 5 Barisal 10 Dhaka No of link Region

8. Case study : PTAGR1-BSBOA2 Interference affect: Location : Barisal Frequency : 7 GHz (U3) TX : 7498 MHz, RX : 7743 MHz Horizontal link: Vertical link: Average SES/Site/Week: RX : N/A (no interference) TX OFF RX : -35/-36 dBm TX ON BSBOA2 PTAGR1 RX : -52/-53 dBm (huge interference) TX OFF RX : -35/-36 dBm TX ON PTAGR1 BSBOA2 RX : N/A (no interference) TX OFF RX : -35/-36 dBm TX ON BSBOA2 PTAGR1 RX : -62/-68 dBm (huge interference) TX OFF RX : -35/-36 dBm TX ON PTAGR1 BSBOA2

9. Case study cont.. TGKCB1-TGCLP1 Location : Thakurgaon, Rajshahi Frequency : 8 GHz TX : 7955 MHz, RX : 8266 MHz Normal RX level: 31 dBm Fade margin: 38 dBm Interference affect: Average SES/Site/Week: RX : -53/-54 dBm (huge interference) TX OFF RX : -31/-32 dBm TX ON TGCLP1 TGKCB1 RX : N/A (no interference) TX OFF RX : -31/-32 dBm TX ON TGKCB1 TGCLP1

11. THANKS