appendix c.how to analyze bases at ion feeder cross or wrong connection

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Appendix C How to Analyze Cross or Wrong Connection of Base Station Feeder

Drafted by Checked by Revised by Approved by

Zhang Xifeng Jiang Minggang TD-SCDMANetwork Plan & Optimization Dept.

Date Date

2008-1-2 2008-1-2

Date

2008-8-5

Date

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Contents1 Cross or Wrong Connection of Antenna Feeders for a CDMA or GU BTS ..............I 1.1 Overview ...............................................................................................................I 1.2 Diagram of BTS antenna feeder connection ...................................................I 1.2.1 Definition of sector and antenna feeder cable..........................................I 1.2.2 Relation between antenna feeder and the antenna feeder port on the top of the cabinet .................................................................................................... II 1.3 Typical cases of cross and wrong connection .............................................. III 1.3.1 Two Tx of two sectors connect to the same antenna ........................... IV 1.3.2 Inversely connected Tx of two sectors ................................................... IV 1.3.3 Inversely connected Rx of two sectors .................................................... V 1.3.4 Inversely connected Rx/Tx of two sectors ............................................. VI 1.4 Method of detecting cross or wrong antenna feeder connection ............ VII 1.4.1 Sorting feeder cable ................................................................................ VII 1.4.2 Reading the length of feeder cable ...................................................... VIII 1.4.3 Test with the cell phones debugging mode ........................................ VIII 1.4.4 Drive test ...................................................................................................... X 1.4.5 Checking lock finger numbers ................................................................. XI 1.5 Solutions to cross or wrong antenna feeder connection ......................... XIII 2 Special Topic on Analysis of Wrong Antenna Feeder Connection at Single TD-SCDMA Site ....................................................................................................................... 1 2.1 Overview .............................................................................................................. 1 2.2 Connection Diagram of BS Antenna Feeder .................................................. 1 2.2.1 Sector and Antenna Feeder Definitions ................................................... 1 2.2.2 Corresponding Installation Relations of BS Antenna Feeder Fibers with Fiber Interfaces at Cabinet Top ..................................................................... 3 2.3 Analysis of Typical Cases Wrong Connection of Antenna Feeders (Inverse Connection of Fibers) ...................................................................................... 4 2.3.1 Transmitting Ends of Two Sectors Connected to Same Antenna ........ 4 2.3.2 Inverse Connection of Transmitting Ends of Two Sectors ..................... 5 2.3.3 Inverse Connection of Receiving Ends of Two Sectors ......................... 7 2.3.4 General Inverse Connection of Two Sectors ........................................... 8 2.4 Check Methods of Wrong Fiber Connection................................................... 9 2.4.1 Test Methods of Mobile Phone Engineering Mode ................................. 9 2.4.2 Line Test Analysis ...................................................................................... 10 2.4.3 Tidying Feeders .......................................................................................... 12 2.5 Solution to Wrong Fiber Connection .............................................................. 12

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List of FiguresFigure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Schematic Diagram of Sectors ....................................................................I Schematic Diagram of Antenna Feeder (Dual Polarization Antenna) .. II Schematic Diagram of Antenna Feeder................................................... III Case 1: Tx of 2 Sectors Connecting to the Same Antenna .................. IV Case 2: Inversely Connected Tx of 2 Sectors ......................................... V Case 3: Inversely Connected Rx of 2 Sectors ........................................ VI Case 4: Inversely Connected Rx/Tx of 2 Sector .................................. VII Schematic Diagram of Debugging Mode of a Cell Phone .................... IX Drive Tests in the Case of Wrong Feeder Connection ........................... X Drive Tests after Wrong Feeder Connection Is Corrected .................. XI Lock Finger Status (Not Balanced) before Feeder Correction ......... XII Lock Finger Status (Balanced) after Feeder Correction ................... XII

List of TablesTable 1 Solutions to Cross/Wrong Antenna Feeder Connection ...................... XIII


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1 1.1

Cross or Wrong Connection of Antenna Feeders for a CDMA or GU BTS Overview

As subcontractors are undertaking more and more mobile telecommunication construction projects, cross or wrong connections are widely found due to problems of the professional qualification, experience and work attitude of the project undertakers. Although the problems may be concealed temporarily for reasons of subcontractor verification, project management or deadline satisfaction, they will give rise to serious problems in network quality, project progress and customer satisfaction sooner or later. To prevent unnecessary losses and make future network optimization easier, we should check the construction quality of every BTS site seriously.

In this chapter well take the CDMA system as example to discuss the cross and wrong connections of antenna feeder.1.2 Diagram of BTS antenna feeder connection Note: Since one all-IP RF link supports four carriers, well take a 3-sector all-IP BTS (4 carriers or less) as example for analysis. The analysis also applies to Hirs or Ae 1-carrier BTS. The antenna here refers to dual polarization antenna, but the analysis here can also roughly apply to a single polarization antenna. The discussion here will not cover the following cases:1. 2. 3. 4. Hirs BTS or BTS Ae; All-IP BTS (with more than 4 carriers); Omni-directional BTS, which cannot have the problem of cross or wrong connection; 6 sectors.

1.2.1 Definition of sector and antenna feeder cable Sector: As shown below, sector is formed by clockwise rotation from the right north direction, then sector and sector in turn:

Figure 1

Schematic Diagram of Sectors

Antenna feeder: Corresponding to sector , and , the antenna feeders are defined as ANT1, ANT2, ANT3, ANT4, ANT5 and ANT6 in clockwise order as shown below:


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Figure 2

Schematic Diagram of Antenna Feeder (Dual Polarization Antenna)

1.2.2 Relation between antenna feeder and the antenna feeder port on the top of the cabinet ANT1-->RFE0_ANT (sector Tx/Rx, both ends of the main feeder bear the label TX0/RX0); ANT2-->RFE1_ANT (sector Rx, both ends of the main feeder bear the label RX0); ANT3-->RFE2_ANT (sector Tx/Rx, both ends of the main feeder bear the label TX1/RX1); ANT4-->RFE3_ANT (sector Rx, both ends of the main feeder bear the label RX1); ANT5-->RFE4_ANT (sector Tx/Rx, both ends of the main feeder bear the label TX2/RX2); ANT6-->RFE5_ANT (sector Rx, both ends of the main feeder bear the label RX2). Here well describe the transmit end as Tx/Rx and the reception end as Rx. The diagram of antenna feeder connection is shown below:


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ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

BT

Figure 3 1.3

Schematic Diagram of Antenna Feeder

Typical cases of cross and wrong connection

Note: Its often found that the antenna feeder cables are connected wrongly between two sectors. Well see such case study here. Wrong connection among three sectors is a bit more complicated but can be broken down into the case for every two sectors. Because there are four RFE feeder ports on the top of the BTS cabinet and the antenna also has four ports, there can be 4*3*2*1=24 connection combinations. If reverse connection is allowed for antenna feeders of the same sector, (for example, RFE0_ANT with ANT2, RFE1_ANT with ANT1), then there are 2*1*2*1=4 completely correct connection combinations. Strictly speaking, 20 of the combinations are not correct and therefore, the probability for wrong connection can be very high: 20/24*100%=83.33%. Lets look at some typical cases of wrong connection here, all of which can affect systems coverage seriously:


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Internal Use 1.3.1 Two Tx of two sectors connect to the same antennaThis case is the least wanted as it leads to bad coverage of a sector right away while for another sector, there will be two strong pilots with equal strength. This mistake can usually be detected with the drive test or the cell phones debugging mode test. Typical wrong connection:

ANT1-->RFE0_ANT; ANT2-->RFE2_ANT; ANT3-->RFE1_ANT; ANT4-->RFE3_ANT.

ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

BTS

Figure 4

Case 1: Tx of 2 Sectors Connecting to the Same Antenna

1.3.2 Inversely connected Tx of two sectorsInversely connected Tx of two sectors will lead to confusing network topology and wrong neighbor cell configuration. Besides, the diversity reception gain of the two sectors will be almost zero in this case.Confidential and Proprietary Information of ZTE CORPORATION

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Internal UseThis mistake can usually be detected with the drive test or the cell phones debugging mode test. Typical wrong connection:


ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

BTS

Figure 5

Case 2: Inversely Connected Tx of 2 Sectors

1.3.3 Inversely connected Rx of two sectorsThe diversity reception gain of the two sectors will be almost zero in this case. Inversely connected Rx of two sectors can hardly be detected with tests. Instead, its usually found out when you sort out feeder cables from top down. Typical wrong connection:

ANT1-->RFE0_ANT; ANT2-->RFE3_ANT;Confidential and Proprietary Information of ZTE CORPORATION

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Internal Use ANT3-->RFE2_ANT; ANT4-->RFE1_ANT.

ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

BTS

Figure 6

Case 3: Inversely Connected Rx of 2 Sectors

1.3.4 Inversely connected Rx/Tx of two sectorsThis mistake will lead to confusing network topology and may easily cause wrong neighbor cell configuration. At least the wrongly connected Tx can usually be detected with the drive test or the cell phones debugging mode test. Typical wrong connection:



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ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

BTS

Figure 7 1.4

Case 4: Inversely Connected Rx/Tx of 2 Sector

Method of detecting cross or wrong antenna feeder connection

The method of eye survey as described in the Guide to BTS Installation Acceptance is obviously not proper. The proper methods are described as follows: 1.4.1 Sorting feeder cable The most efficient and proper way to check antenna feeders connection status is to sort the cables. It is also the recommended method if the main feeder cable is routed clearly.1. Description

Sort the cables segment by segment along their routes from top down (from antenna to the top of the cabinet) and from bottom up (from the top of the cabinet to antenna).2. Precautions

Remember that the directions of the indoor and outdoor reference systems are different when you are sorting the cables at the feeder window. Also note that theConfidential and Proprietary Information of ZTE CORPORATION

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Internal Use feeder cable may cross each other. Its advisable to draw a diagram to avoid mistakes.3. Pros and cons

Pros: The most reliable method that is easy to use. Cons: The method is not applicable if the main feeder doesnt run in a clear route or some part of the routing is invisible. If a tower is involved in the project, a person should climb up to the tower to check the routing. It is also necessary to enter the equipment room to check the routing. 1.4.2 Reading the length of feeder cable Read the length of feeder cable to check its connection if the first method is not feasible.1. Description

6 main feeder cables are usually cut out segment by segment from the same coil of cable. A 4-digit number is marked for every meter of the main feeder cable. This number and the rough cable length (from antenna end to the top of the cabinet) can help us check the connection status between feeder cables. This is because if the feeder cables are correctly connected, then the difference between the numbers at both ends of every main feeder cable is roughly equal to the length of the main feeder cable. The steps of examination are:1) On the top of the cabinet, read the numbers marked at the end of every main feeder cable and record them in the order of the RFE ports: (D1, D2, D3, D4, D5 and D6); 2) Near the antenna end, read the numbers marked at the end of every main feeder cable and record them in the order of the sectors (U1 and U2 for sector 1, U3 and U4 for sector 2, and U5 and U6 for sector 3); 3) Calculate |U1D1|, |U2D2|, |U3D3|, |U4D4|, |U5D5| and |U6D6|, and judge whether the results are nearly the same (roughly the length value of the feeder cable); 4) If the connection is correct, then the difference should be approximately the same as the length of the main feeder. Otherwise, there can be a connection mistake and if this is true, analyze the readings find out which feeder cables are wrongly connected. 2. Precautions

The sector sequence at the antenna side must not be mistaken. This method requires that all six feeder cables are from the same coil of cable where the numbers on the cable follow some regularity.3. Pros and cons

Pros: It is a quite reliable method that ignores the routing mode of the main feeder. Cons: It is a difficult method that requires clear understanding of the working principle of the method. It requires that all six feeder cables are from the same coil of cable. If a tower is involved in the project, a person should climb up to the tower to check the routing. It is also necessary to enter the equipment room to check the routing. 1.4.3 Test with the cell phones debugging mode This method is preferable in routine test and is not recommended for checking the connection status of feeder cables.1. Description

There are two specific methods as below:


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Internal Use If the antenna is easily accessible (when the antenna is located on the roof of a building), pull out the antenna of the cell phone and put it right before the antenna panel. Now check the PN and its strength right before every antenna to see whether the transmit power of every sector is the same as planned; If the antenna is not easily accessible (when the antenna is located on the tower), go around the BTS to see whether the transmit power in the main lobe direction of every sector is the same as planned.

Method of checking PN and its strength with the cell phones debugging mode: The diagram below shows the debugging mode of a cell phone. Now query the pilot PN and its strength Ec/Io. The PN is 174 and its strength Ec/Io is -15dB in the case given below. The debugging mode varies with different cell phone models but usually the parameters as shown below are given.

1: Transmit power adjustment (dB) of cell phone; 2: Reception power (dBm) of cell phone; 3: Pilot strength Ec/Io (dB) 4: Pilot PN 5: Frequency

Figure 82. Precautions

Schematic Diagram of Debugging Mode of a Cell Phone

If the test is conducted around the BTS, remember to keep the test locations some distance away from the BTS (at least not right under the BTS). The locations should not be too far from the BTS either, lest the pilot strength of two neighbor sectors are almost the same and no judgment can be made in this case. The test should be conducted in all main lobe directions of the sectors.3. Pros and cons

Pros: It is a reliable method for transmit power test. There is no need for test on the tower or in the equipment room. There is no need to check the feeder cable. Cons: Only the transmit power (not the reception power) can be tested roughly. TheConfidential and Proprietary Information of ZTE CORPORATION

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Internal Use test conductor should learn how to use the cell phones debugging mode. The cell phone with the available debugging functions is needed. Test can only be conducted when the main lobe direction of the sector is reachable. 1.4.4 Drive test This method is similar to the method with the cell phones debugging mode. It is recommended in routine tests and should better not used directly for checking the feeder connection.1. Description

In the process of drive test, observe several strongest pilot PNs and their strengths (Ec/Io) to see whether the main lobe direction of each sector is the same as planned. We can also check whether the main lobe direction of each sector is the same as planned by analyzing the drive test result, that is, the coverage range of each PN. The diagrams below show the drive test status in the case of wrong feeder connection and after the wrong connection is corrected. The diagrams are for reference only.

a) Main lobe direction for coverage from PN210 to PN42 PN210

b) Main lobe direction for coverage from PN42 to

Figure 9

Drive Tests in the Case of Wrong Feeder Connection


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a) PN42 coverage is corrected

b) PN210 coverage is corrected

Figure 102. 3. Precautions

Drive Tests after Wrong Feeder Connection Is Corrected

The drive tests should cover the main lobe direction of all sectors of the BTS.Pros and cons

Pros: It is a reliable method for transmit power test. There is no need for test on the tower or in the equipment room. There is no need to check the feeder cable. More pilot PNs can be seen with this method than with the cell phones debugging mode. Cons: Only the transmit power (not the reception power) can be tested roughly. The test conductor should learn how to use the drive test tools. The drive test tools are needed. Test can only be conducted when the main lobe direction of the sector is reachable. 1.4.5 Checking lock finger numbers This method is usable only when the BTS is carrying some traffic. It is an auxiliary approach and should better not used directly for checking the feeder connection.1. Description

In OMC, query the CES performance data that includes lock finger of main and diversity antenna. If antenna connection is correct, the lock finger of main and diversity antenna should be roughly the same. If the difference is great, there can be a cross or wrong connection of feeder cable. The two diagrams below show the lock finger status before and after feeder connection is corrected. The diagrams are for reference only.


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300000 250000 200000 150000 100000 50000 0

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BSS Lock Finger 0 Number


Figure 11

Lock Finger Status (Not Balanced) before Feeder Correction

250000 200000 150000 100000 50000 0

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Figure 122. Precautions

Lock Finger Status (Balanced) after Feeder Correction

This method is usable only when the BTS is carrying some traffic. In this case, the lock numbers is usually tens of thousand per hour.3. Pros and cons

Pros: There is no need for test on the tower. There is no need to check the feeder cable. It is convenient and applicable for wide range of checkups. Cons: The lock finger problem does not necessarily indicate cross or wrong feeder connection. That is to say, another method (drive test or sorting the feeder cable) is needed to help determine the real connection status. The test conductor should be familiar with OMC operations.


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2007-07-09 19:00:00 2007-07-09 20:00:00

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Internal Use 1.5 Solutions to cross or wrong antenna feeder connection

Solution: Exchange the wrongly connected jumpers on the top of the cabinet; also exchange the labels of main feeders wrongly pasted. Note: After the correction, use the above methods to verify the connection again lest any connection error is not corrected or any originally correct connection is misplaced by mistake. Jumper exchange is a method to solve the connection problem quickly and easily. However, It may look untidy or even affect the procedure of installation acceptance. Therefore, the way to solve the problem once and for all is to make the corrections as required in related engineering specifications, including rectifications of the feeder, jumper and label of main feeder. Lets see several typical corrections here:Table 1 Solutions to Cross/Wrong Antenna Feeder Connection SN 1 Connection status Test method 1) 2) 3) 4) 5) 2 Cell phones debugging mode Drive test Sorting feeder cable Reading length of feeder cable Lock finger numbers (auxiliary) Cell phones debugging mode Drive test Sorting feeder cable Reading length of feeder cable Lock finger numbers (auxiliary) Sorting feeder cable Reading length of feeder cable Lock finger numbers (auxiliary) See Figure 4: 1) Exchange the jumpers of RFE1 and RFE2, and exchange the label of main feeder; 2) The ultimate solution is engineering rectification. See Figure 5: 1) Exchange the jumpers of RFE0 and RFE2, and exchange the label of main feeder; 2) The ultimate solution is engineering rectification. See Figure 6: 1) Exchange the jumpers of RFE1 and RFE3, and exchange the label of main feeder; 2) The ultimate solution is engineering rectification. 4 Solution

Two Tx of two sectors connect to the same antenna Inversely connected Tx of two sectors

1) 2) 3) 4) 5)

3

Inversely connected Rx of two sectors

1) 2) 3)

Inversely connected Rx/Tx of two sectors

1) 2)

Sorting feeder cable Reading length of feeder cable

See Figure 7: 1) Exchange the jumpers of RFE0 and RFE2, and exchange the jumpers on RFE1 and RFE3. Also exchange the label of main feeder; 2) The ultimate solution is engineering rectification.

3) Cell phones debugging mode (auxiliary) 4) 5) Drive test (auxiliary) Lock finger numbers (auxiliary)


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2 Special Topic on Analysis of Wrong Antenna Feeder Connection at Single TD-SCDMA Site 2.1 Overview

In the actual construction of mobile communication project, it is common to wrongly connect the antenna feeder, and the cause is closely related to the construction teams project implementation capacity, actual experience, sense of responsibility, etc. In addition, more and more projects are outsourced. Lots of problems are hidden due to fulfillment failure of the outsourcing authentication work, blindly keeping up with the schedule, and various defects in project management. Once breaking out, a minor problem possibly turns into a major problem, and at least affects the network quality, project progress and customer satisfaction. Slight negligence may lead to great disaster. Single site check work is not negligible, but always ignored in the actual project or wound up hastily, thus undoubtedly increasing the pressure and workload of network optimization. It is worth speculating about the problem of execution quality in the single site check (or BS acceptance) link of actual project, and all the related parties need to make great efforts to solve the problem. With the TD-SCDMA Node B as an example, this document aims to analyze the problem of wrong antenna feeder connection, and omits the description of project execution. 2.2 Connection Diagram of BS Antenna Feeder This document uses the 3-sector Node B with 2/3 carrier frequencies or above as an example. Moreover, it analyzes the intelligent antenna. Analysis of other types is similar to the content here. 2.2.1 Sector and Antenna Feeder Definitions First, the sectors and antenna feeders are defined as follows: Sector: By clockwise rotating in the north direction, they are sector 1, sector 2 and sector 3 in turn, as shown below.

Figure 1

Sector Definition

Antenna feeder: By clockwise rotating, the corresponding fibers of sector 1, sector 2Confidential and Proprietary Information of ZTE CORPORATION

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and sector 3 are ANT1, ANT2, ANT3, ANT4, ANT5 and ANT6 in turn, as shown below.

Figure 2

Antenna Feeder Definition (Dual Polarization Antenna)


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2.2.2 Corresponding Installation Relations of BS Antenna Feeder Fibers with Fiber Interfaces at Cabinet Top Below are the corresponding installation relations of R04 fibers with TORN board fiber interfaces: ANT1>RFE0_ANT (Tx of sector 1; both the fiber ends are tied with the label TX0) ANT2>RFE1_ANT (Rx of sector 1; both the fiber ends are tied with the label RX0) ANT3>RFE2_ANT (Tx of sector 2; both the fiber ends are tied with the label TX1) ANT4>RFE3_ANT (Rx of sector 2; both the fiber ends are tied with the label RX1) ANT5>RFE4_ANT (Tx of sector 3; both the fiber ends are tied with the label TX2) ANT6>RFE5_ANT (Rx of sector 3; both the fiber ends are tied with the label RX2) To put it simple, Tx/Rx is used to indicate the transmitting end, and Rx is used to indicate the receiving end. Figure 3 shows the fiber connection diagram.


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3

ANT5

ANT6

2ANT4 ANT3

1

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

Node B

Figure 3 2.3

Connection of Node B to R04 Fibers

Analysis of Typical Cases Wrong Connection of Antenna Feeders (Inverse Connection of Fibers)

The TORN board in the BS cabinet is installed with 6 pairs of fiber interfaces (only 3 pairs are in use normally), and they may be wrongly connected easily. Strictly speaking, a big number of combinations are wrong connections, so the probability of wrong fiber connection is rather high. Once wrong connection occurs, the performance index will be greatly affected. The content below analyzes several typical cases with severe effect on the system coverage. 2.3.1 Transmitting Ends of Two Sectors Connected to Same AntennaThis is the worst case among wrong fiber connections, which directly results in poor coverage of a sector, and two equivalent strong pilots in the other sector. Usually, this fault is found in the line test or engineering mode test with mobile phone. Typical cases:

ANT1>RFE0_ANT ANT2>RFE2_ANT ANT3>RFE1_ANT


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ANT4>RFE3_ANT

3

ANT5

ANT6

2ANT4 ANT3

1

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

Node B

Figure 4

Transmitting Ends of Two Sectors Connected to the Same Antenna

2.3.2 Inverse Connection of Transmitting Ends of Two SectorsThis case is also severe among wrong antenna feeder connections, and leads to disorder of the network topology structure and wrong neighbor cell configuration. Moreover, the diversity receiving gains of these two sectors are both almost 0. Usually, this fault is found in the line test or engineering mode test with mobile phone. Typical cases:

ANT1>RFE2_ANT ANT2>RFE1_ANT ANT3>RFE0_ANT ANT4>RFE3_ANT


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ANT5

ANT6

ANT4 ANT3

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

Node B

Figure 5 Inverse Connection of Transmitting Ends of Two Sectors


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2.3.3 Inverse Connection of Receiving Ends of Two SectorsThis case generates great effect among wrong antenna feeder connections. Consequently, the diversity receiving gains of these two sectors are both almost 0. It is hard to find out this fault through a test. The only way is to tidy up fiber lines from top down. Typical cases:


3

ANT5

ANT6

2ANT4 ANT3

1

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

Node B

Figure 6 Inverse Connection of Receiving Ends of Two Sectors


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2.3.4 General Inverse Connection of Two SectorsThis case generates minor effect among wrong fiber connections, and leads to disorder of the network topology structure and wrong neighbor cell configuration. Usually, at least inverse connection of transmitting ends can be found in the line test or engineering mode test with mobile phone. Typical cases:


3

ANT5

ANT6

2ANT4 ANT3

1

ANT1

ANT2

RFE1 RFE0

RFE3 RFE2

RFE5 RFE4

Node B

Figure 7

General Inverse Connection of Two Sectors


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2.4

Check Methods of Wrong Fiber Connection

The current guide to Node B installation acceptance provides the acceptance method of eye survey, which is apparently wrong. One cannot verify if the antenna feeder is correctly connected only by eye survey. Several check methods are described below, and can be used as a reference in the process of engineering installation acceptance. 2.4.1 Test Methods of Mobile Phone Engineering Mode This method is applicable to the routine test. It is not recommended to directly use this method to check the antenna feeder connection.4. Main methods: 1 When it is easy to approach the antenna (e.g., the antenna is located on the building roof), pull out the mobile phone antenna and make it close the front side of antenna panel. Check the SC in front of each antenna and its strength, and if the transmitting end of each sector is consistent with the planning (this method is hardly applied to the actual work, and check is rather difficult even the method is used). 2 When it is uneasy to approach the antenna (e.g., the antenna is located on the iron tower), move around the BS (about 50 m~100 m from the antenna), and check if the transmitting end at main lobe direction of each sector is consistent with the planning.

You can check the connection with one of the following two methods:

In the engineering mode, check the SC and its PCCPCH RSCP strength as follows: The mobile phone enters the engineering mode (depending on the mobile phone), as shown below. Check the pilot SC (marked as 4 in the diagram) and its strength Ec/Io (marked as 3 in the diagram). The diagram displays the SC as 174 and its strength Ec/Io as -15dB. The engineering mode of each model of mobile phone is different in the display mode and content. Only an example is provided in the diagram. The specific diagram depends on the mobile phone model, but generally includes the parameters marked below.


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1) Scramble 2) Power of PCCPCH-RSCP 3) Main carrier frequency 4) Transmit power of mobile phone 5) Receiving power of mobile phone Figure 85. Precautions

Engineering Mode of Mobile Phone

When you conduct a test by moving around the BS, do not keep the test point too close (not directly under the BS at least) or too far (in this case, the pilot strengths of two neighbor sectors may be equivalent and cannot be judged) from the BS. The main lobe direction of each sector must be tested.6. Advantages and disadvantages:

Advantages: It is accurate in testing the transmitting end; you need not climb up the tower or enter the equipment room; you need not directly check the antenna feeder. Disadvantages: You can only approximately judge if the transmitting end is correct, but not the receiving end; the operator needs to use the engineering mode of mobile phone; the mobile phone that supports engineering mode is required; the test cannot be conducted when the main lobe direction of sector is unreachable. 2.4.2 Line Test Analysis This method is similar to Test Methods of Mobile Phone Engineering Mode and applicable to the routine test. It is not recommended to directly use this method to check the antenna feeder connection.


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7.

The method is described as follows:

In the line test, check to see if the main lobe direction of each sector is consistent with the planning by observing the strongest pilot SCs and their strength Ec/Io. Besides, when you handle and analyze the line test data afterwards, you can also check to see if the main lobe direction of each sector is consistent with the planning by analyzing the coverage scope of each SC. The diagrams below compare the line test of finding wrong connection of antenna feeders and line test after rectification, and are used for reference only.

a) SC210 coverage to the SC42 main lobe direction b) SC42 coverage to the SC210 main lobe direction Figure 9 Line Test of Finding Wrong Antenna Feeder Connection

a) SC42 coverage direction already correct b) SC210 coverage direction already correct Figure 10 Line Test after Antenna Feeder Rectification


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Internal Use

8. 9.

Precautions Advantages and disadvantages:

You need to test the line coverage to the main lobe direction of each sector at the BS. Advantages: It is accurate in testing the transmitting end; you need not climb up the tower or enter the equipment room; you need not directly check the antenna feeder; you can see more pilot SCs in comparison with Test Methods of Mobile Phone Engineering Mode. Disadvantages: You can only approximately judge if the transmitting end is correct, but not the receiving end; the operator needs to know how to use line test tools; a set of line test tools is required; the test cannot be conducted when the main lobe direction of sector is unreachable. 2.4.3 Tidying Feeders This is the most effective and accurate method for other systems. This method is preferred if the main feeder is clearly routed. However, this method is infeasible and not recommended for the TD-SCDMA system because the smart antenna is used, and ZTEs current products from R04 to Node B are fiber access. It is not described here. 2.5 Solution to Wrong Fiber Connection

Solution: Just adjust the fiber at the TORN board. If the label pasted at the wrongly connected fiber is also incorrect, it must be changed. Note: After adjustment, you need to verify the result using the above check method, lest the adjustment may fail or the original correct connection is made wrong in the adjustment.


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appendix c.how to analyze bases at ion feeder cross or wrong connection

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