2008-11-3                                             Security Level:How to Analyze Crossed FeederIssue by DT             ...
Outline• What is crossed feeder issue• The problems raised by crossed feeder issue• How to detect crossed feeder issue by DT
What is crossed feeder issue (1)  The term crossed feeder is used to describe the problem that arises when  the feeders fo...
What is crossed feeder issue (2)The crossed feeder problem would ariseif the feeder for sector A is connected tosector C a...
What is crossed feeder issue (3)  There are server types of crossed feeder:          Crossed transmit feeders          Cro...
The problems raised by crossed feeder issue        Normal Situation                               Crossed Feeder Situation...
The problems raised by crossed feederissue    Crossed feeder will raise many problems, such as:             A greater degr...
How to detect crossed feeder issue by DTCrossed transmit feeders Crossed transmit feeders will result in the swap of 2 orm...
How to detect crossed feeder issue by DT Crossed transmit feeders     In the example shown above, point A is in the area o...
How to detect crossed feeder issue by DT  Crossed receive feeders  It is not easy to detect this fault by DT, because the ...
How to detect crossed feeder issue by DT Crossed receive feeders  The MR measurement is very useful in detecting this type...
How to detect crossed feeder issue by DT  Crossed transmit and receive feeder    The symptom is similar with the fault “cr...
Thank youwww.huawei.com
Upcoming SlideShare
Loading in …5
×

DT analysis how to analyze crossed feeder issue by dt

6,842 views
6,634 views

Published on

Published in: Technology, Business
0 Comments
9 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
6,842
On SlideShare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
635
Comments
0
Likes
9
Embeds 0
No embeds

No notes for slide

DT analysis how to analyze crossed feeder issue by dt

  1. 1. 2008-11-3 Security Level:How to Analyze Crossed FeederIssue by DT www.huawei.com HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential
  2. 2. Outline• What is crossed feeder issue• The problems raised by crossed feeder issue• How to detect crossed feeder issue by DT
  3. 3. What is crossed feeder issue (1) The term crossed feeder is used to describe the problem that arises when the feeders for two or more sectors in a site are inadvertently connected incorrectly. For Example, consider a new cell site that has three sectors, A, B, and C:HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 3
  4. 4. What is crossed feeder issue (2)The crossed feeder problem would ariseif the feeder for sector A is connected tosector C and vice versa. When thishappens, the sectors typically continueto provide good coverage. However, thenetwork parameters for the two sectorsare also reversed. For example, theparameters storing the sectors BCCHand lists of adjacent sectors would beswapped.For example, suppose we run a drivetest through the area served by the cellwhose feeders are crossed display theServBCCH attribute on the Map whilethe cell sectors are colored by BCCH.This is what we might see:HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 4
  5. 5. What is crossed feeder issue (3) There are server types of crossed feeder: Crossed transmit feeders Crossed receive feeders Crossed transmit and receive feedersHUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 5
  6. 6. The problems raised by crossed feeder issue Normal Situation Crossed Feeder Situation HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 6
  7. 7. The problems raised by crossed feederissue Crossed feeder will raise many problems, such as: A greater degree of interference A poor uplink signal strength A poor performance of handoverHUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 7
  8. 8. How to detect crossed feeder issue by DTCrossed transmit feeders Crossed transmit feeders will result in the swap of 2 ormore sectors BCCH frequency and TCH’s. As the sectors arepointing in the incorrect direction, performance will suffer asthe frequency plan has been changed and a greater degree ofinterference will be present. In DT, we will find that the handset receives the singlewhich shouldnt have been received in the current cell.HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 8
  9. 9. How to detect crossed feeder issue by DT Crossed transmit feeders In the example shown above, point A is in the area of coverage of Cell D3, but the handset at point A receives the stronger signal of Cell D2. It indicates that TX feeders were crossed between Cell D3 and Cell D2. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 9
  10. 10. How to detect crossed feeder issue by DT Crossed receive feeders It is not easy to detect this fault by DT, because the BCCHfrequencies will appear exactly as they were designed. However,the statistics for the cell would help us to detect the fault: Uplink signal strength would be very poor Link balance would be larger than expected Handover success rate would be very low HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 10
  11. 11. How to detect crossed feeder issue by DT Crossed receive feeders The MR measurement is very useful in detecting this type of feeder cross. Uplink-and-Downlink Balance Measurement per TRX and TCH Receive Level Measurement per TRX maybe are the most useful statistics . For example, if the uplink-and-downlink balance is always in level 10 or level 11, we can consider that there is something wrong in the receive path of the site, crossed receive feeder is a possible problem. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 11
  12. 12. How to detect crossed feeder issue by DT Crossed transmit and receive feeder The symptom is similar with the fault “crossed transmit feeder”, and we can detect the fault by DT easily . HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 12
  13. 13. Thank youwww.huawei.com

×