Frequency Planning Theory 20010323 B 1.0

Huawei Technologies Co. Ltd Wireless Planning and Designing Department

Document No. Product Version Classification

Product Name：GSM900/1800 Total 15 pages

Frequency Planning Theory

Version 1（2001,0323） (Only for internal use)

Written by： Technical support group of wireless planning and design department

Date： 2001/03/23

Reviewed by： Date： yyyy/mm/dd

Reviewed by： Date： yyyy/mm/dd

Approved by： Date： yyyy/mm/dd

Shenzhen Huawei Technologies Co. Ltd

All rights reserved, any violation of the copyright will be investigated

Huawei Wireless planning and Designing Department Frequency Planning Theory

Revision Record Date Revised

Version Note Written by

2001/03/13 1.00 The first draft is completed Zengshuhui, Sifazhong, Zhaoqiyong

All rights reserved, any violation of the copyright will be investigated 2 of 18

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Table of Contents

Frequency Planning Theory.............................................................................................................4 1 Introduction..................................................................................................................................4 2 Requirements for Frequency Division and Carrier to Interference Ratio..............................4

2.1 GSM900..............................................................................................................................4 2.2 DCS1800 ............................................................................................................................5 2.3 Requirements for Carrier to Interference Ratio ..................................................................5

3 Frequency Multiplexing Technologies ......................................................................................5 3.1 4*3 Multiplexing Mode.........................................................................................................5 3.2 Close Multiplexing Technology ...........................................................................................6

4 Frequency Planning ....................................................................................................................7 4.1 Frequency Band Dividing....................................................................................................7 4.2 Frequency Planning Principle .............................................................................................8

5 Cases Analysis ............................................................................................................................9 5.1 Case 1（Close Frequency Multiplexing） ..........................................................................9

5.1.1 Preliminary Planning ................................................................................................9 5.1.2 Final Frequency Planning ......................................................................................10 5.1.3 Conclusion..............................................................................................................11

5.2 Case 2（1X3 Frequency Multiplexing）...........................................................................11

6 Conclusion .................................................................................................................................12 Appendix 1 Frequency Hopping....................................................................................................14

I. Several Concepts in Frequency Hopping .......................................................................14 II. Frequency Hopping Algorithm .......................................................................................15 III. Overview of Frequency Hopping Data Configuration ...................................................16

Appendix 2 Concept of Synchronization Cell........................................................................18



Frequency Planning Theory

Abstract：Frequency planning is one of the several most important factors which influence the wireless network quality. This paper describes several common frequency planning modes and part of the examples.

Key words: Frequency planning Network quality

1 Introduction

Developed till now, capacity of the cellular system is limited in a certain degree by the frequency bandwidth. The frequency can meet the capacity requirements in a certain area only when it is multiplexed. But the frequency multiplexing, especially the close frequency multiplexing mode, will certainly make us face the problem of how to reduce the interference of the same and neighboring frequencies. In the same area, if the frequency multiplexing distance is longer, interference of the same and neighboring frequencies will be less and the capacity will be smaller. If the frequency multiplexing distance is closer, the capacity will be larger. But this will cause the increasing of the interference from the same and neighboring frequencies. How to get the capacity and voice quality balanced is a problem that must be solved in frequency planning. In other words, a good frequency plan can increase the network capacity while maintaining good voice quality.

2 Requirements for Frequency Division and Carrier to Interference Ratio

The cellular system is generally divided into GSM900M and DCS1800M systems. The carrier frequency interval is 200KHz. The up and down frequencies are divided as follows:

Network type Frequency bandwidth（up/down）（MHz） GSM900 890～915/935～960 DCS1800 1710～1785/1805～1880

2.1 GSM900

There are 124 frequency points totally, the sequence numbers （ARFCN）are 1～124. Each end is left with a protection bandwidth of 200KHz. According to the stipulations of our country, the mobile telephone occupies 890～909/935～954MHz， and the Unicom occupies 909～915/954～960MHz. Relation of the frequency and the sequence number （n）is as follows：

The base-station receives：f1（n）＝890.2＋（n－1）×0.2 MHz

The base-station sends： f2（n）＝f1（n）＋45 MHz



2.2 DCS1800

There are 374 frequency points totally. The sequence numbers（ARFCN）are from 512～885. Relation of the frequency and the sequence number（n）is as follows:

The base-station receives: f1（n）＝1710.2＋（n－512）×0.2 MHz

The base-station sends：f2（n）＝f1（n）＋95 MHz

2.3 Requirements for Carrier to Interference Ratio

GSM is an interference-restricted system. According to the requirements for signal demodulation in space interface, GSM stipulates the protection ratio of the same and neighboring frequencies should meet the following requirements：

Carrier to interference ratio of the same frequency： C/I＞9dB； With 3dB allowance left in the project, i.e., C/I＞12dB；

Rejection ratio of the neighboring frequencies： C/A ＞－9dB；With 3dB allowance left in the project, i.e., C/A＞－6dB

3 Frequency Multiplexing Technologies

3.1 4*3 Multiplexing Mode

Frequency points in the available frequency bandwidth are grouped according to different frequency multiplexing modes prior to frequency planning. The most common frequency multiplexing mode in the cellular system is 4*3 frequency multiplexing mode, as shown in the following Figure:



Figure 1 4*3 Frequency multiplexing mode

As can be seen from the above Figure, in 4*3 mode,“4” indicate 4 stations，“3”indicates each station has 3 cells，altogether 12 cells are frequency families. Different cells in the same family have different frequencies. But cells of other families use a group of frequencies from the 12 frequency families repeatedly.

3.2 Close Multiplexing Technology

The development of network construction will certainly bring a rapid increasing of network capacity. In turn, it will raise an even higher demand on network construction. With the dividing of cells and the use of micro-cellular and distributed antenna system, how to plan the frequency properly becomes a subject of challenge. And various close frequency multiplexing technologies have emerged. At present, the most popular ones are MRP of ERISSON company, IUO of NOKIA company and FRACTIONAL REUSE（1×3）of North Telecom. etc.

Different frequency multiplexing technologies needs the support of the corresponding software and hardware technologies. At the same time, the handover, functional control, channel allocation algorithm, DTX and frequency hopping are perfected and developed. It also puts forward higher demands for the selection of antenna. In other words, how to reduce the interference is the key factor to guarantee the system service quality since the frequency multiplexing is very close. In frequency planning, this is shown as the proper selection of base-station position and cell direction, proper setting of antenna height and declination angle to reduce the cross-area coverage. In system functions, it is shown as the use of DTX, frequency hopping technique and the use of BGT handover, functional control of up and down lines, allocation algorithm of optimization channels etc. In parameter setting, it includes proper setting of static power of the base station, various hand-over thresholds, proper setting of frequency hopping parameters to reduce the possibility of the collision of the same and neighboring frequencies in a maximum degree. In addition, it raises higher demands for stray index and the adjacent channel selection index of the base station equipment. This paper will not describe these in detail. See the



related documents for the specific contents. Refer to Appendix 1 for the frequency hopping.

Nearly all-different close multiplexing technologies use the hierarchical concept. Plan BCCH and TCH in different layers. A different layer uses a different frequency-multiplexing mode. Considering that BCCH must always send system information for the test and contact of the mobile phone so as to make the mobile phone decode correctly. At the same time, 12 frequency points must be allocated to BCCH at least to enhance the correctness of mobile phone test report. In the actual allocation, considering the irregularity of base station allocation and variation of azimuth angle of the cell，more than 14 frequency points are generally allocated to BCCH. Its frequency planning is generally done with 4*3 or looser frequency multiplexing mode. Frequency planning of TCH uses 3*3, 2*3 and 1*3 modes etc. It should be pointed out that the purpose of different carrier layer using different multiplexing degree is to avoid the interference as far as possible. It is shown specifically as follows:

In case of the unevenness of network station types, since not all cells will use TRX in the last layer or the last several layers, so TRX in the last layer or the last several layers can realize closer multiplexing degree（even if no frequency hopping）.

As each carrier layer tries to use different multiplexing mode, thus making frequency points of any two cells in the network not completely the same. That is to say, cells with complete the same frequency doesn’t exist.

When multiple frequency multiplexing is implemented, although the interference is increased, TRX is added in the cell at the same time, making more frequencies taken part in frequency hopping, thus make the gain increased.

If frequency points with less interference and greater interference exist in the same cell, make them combined together when the frequency hopping technique is used. The interfered frequency points can still be used normally according to the characteristics of Viterbi decoder. For each burst, although the interference is variable, the voice quality depends on the average value of the interference for a special connection.

4 Frequency Planning

4.1 Frequency Band Dividing

When hierarchical frequency planning is performed with close multiplexing mode, it involves how to divide the frequency band. Generally, sequence segmentation mode and interval segmentation mode can be used. That is to say, sequence numbers （ARFCN）of frequency points allocated in the same layer are continuous or discontinuous. 2~3 frequency points are generally left for planning the microwave cellular or the special case (Mountain station in the downtown area) when cutting the frequency. The following describes the dividing of BCCH and TCH layers in multiple close-multiplexing modes.

Suppose the max. station type is S4/4/4， and the sequence numbers of frequency points are 512～561, 50 frequency points totally, we can divide the frequencies as four layers of BCCH, TCH1, TCH2 and TCH3. In multiple frequency-multiplexing modes, basic principles for determining the multiplexing degree of different carrier layers are allocated to the frequency points layer by layer. Try to keep the multiplexing degrees in different layers to be different and implement close multiplexing layer by layer. The general principle is：BCCH>TCH1>TCH2>TCH3. To keep good voice quality, it is better to control the average multiplexing degree in TCH layer between 7 ～ 8. It is recommended to use 1*3 mode when it is lower than 7. In this example, 12



frequency points are allocated to BCCH layer, and 38 frequency points are allocated to TCH layer.

1）The sequence segmentation can be divided as follows:

BCCH（12）：512 ～523；

TCH（38）：524 ～561

2）The interval segmentation can be divided as follows:

BCCH（12）：512, 514, 516,…,532, 534；

TCH（38）：513, 515, 517, …, 531, 533, 535 ～561

As can be seen from the above planning：frequency planning between layers is of less interference when using continuous planning mode. The interference between layers occurs on the frequency separation point. But the interference from the same and neighboring frequencies should be considered carefully when planning the frequency in the same layer of different cells. When using discontinuous planning mode, it is easy to plan frequencies in the same layer. But the influence of interference between layers is great. So the coordination of between them should be considered carefully.

In case of less available frequencies, such as network of China Unicom, all available frequencies can be used as BCCH frequency point for planning. This will certainly make frequency planning in TCH layer more complicated. But frequency plan got in this way is more reasonable, and the utilization ratio of the limited frequency points is higher. But this kind of frequency plan is of poor adaptability, and it is unfavorable for capacity expansion and frequency modification when optimizing the network. Under the well configuration of base station, 29 frequency points of Unicom can realize S3/3/3 station with 12/9/8 mode.

In 1*3 frequency multiplexing mode, it is of less influence on the interference when TCH layer uses sequence and interval grouping modes. But, in the central city, influence of the neighboring frequency of the opposite adjacent cell is slightly greater than neighboring frequency of the parallel adjacent cell. It is just opposite in the border of the city. The selection of grouping mode depends on the actual conditions.

4.2 Frequency Planning Principle

When planning frequencies in a certain area, it generally uses the mode of geographical area. But a certain number of frequency points should be preserved or the frequency points should be divided at the border of the areas (When the frequency is sufficient). It is better to select borders out of hot spot areas or complicated networking areas. It is generally planned beginning from the most concentrated area of base stations. As the stations are allocated irregularly, it is difficult to guarantee that the carrier frequency in the same layer can be planned completely in 4*3 or 3*3 mode etc. It needs to adjust flexibly according to the actual requirements. Generally, the following principles should be followed no matter which kind of mode is used for frequency planning:

1）The same frequency points are not allowed in the same base station.

2）It is better to make the frequency interval between BCCH and TCH in the same cell higher than 400K.

3）When the frequency hopping is not used, it is better make the frequency interval between TCH in the same cell higher than 400K.



4） In none 1*3 multiplexing mode, avoid the direct adjacent base station to have the same frequency (Even if the main lobe direction of the antenna is different, it is also difficult to predict the influence of the side lobe and back lobe because of the antenna and the environment).

5）Considering the antenna height and the complexity of broadcasting environment, the close opposite base stations with the same frequency should be avoided (Including across from each other).

6）Generally, 1*3 multiplexing should guarantee the number of frequency hopping points is over two times the number of frequency hopping carrier frequencies.

7） Pay special attention to the same frequency multiplexing. Avoid conditions that are the same as BCCH and BSIC to occur in the adjacent area.

8）Start PBGT handover, when the rejection ratio of neighboring frequencies is guaranteed via parameter adjustment, neighboring frequency can be used in direct opposite adjacent cell.

Note：Good network structure is the basis of a good frequency plan. See related documents for specific contents of setting up the network.

5 Cases Analysis

5.1 Case 1（Close Frequency Multiplexing）

5.1.1 Preliminary Planning

Unicom network in a certain area, with concentrated base stations, flat terrain and max. station type S3/3/2.

Divide BCCH and TCH in continuous hierarchical mode. Where, 96～109 frequency points are allocated to BCCH, and 110～124 frequency points are allocated to TCH. It should be avoided as far as possible in frequency planning that opposite cells have the same and neighboring frequencies. But, many opposite cells with the same frequency are in alternate station direction (Including across from each other) , as shown in the following Figure：



同频 The same frequency 1 公里 1 one kilometer 邻频 The neighboring frequency 背向同频 The same frequency in backward direction 两对邻频 Two pairs of neighboring frequencies

As can be seen from the above Figure, obviously, four pairs of opposite cells with the same frequency in alternate station direction. All of them are BCCH frequency points. The interference is only related to the distance between stations and it has nothing to do with whether there is other base station between two cells when engineering parameters and transmitting power are fixed. The result of frequency planning is that there are more complaints because of the poor voice quality and frequent disconnection in urban area.

5.1.2 Final Frequency Planning

With the use of hybrid allocation principle of full band BCCH and TCH, the opposite cells with the same frequency are avoided in frequency planning. But there are many opposite cells with neighboring frequency in the adjacent base station, the same frequency generally occurs on back to back cell, as shown in the following Figure:



同频 The same frequency 1 公里 1 one kilometer 邻频 The neighboring frequency 背向同频 The same frequency in backward direction 两对邻频 Two pairs of neighboring frequencies

The declination angle of the antenna is adjusted a lot while using the frequency plan. At the same time, PBGT handover algorithm is used, and the PBGT handover threshold is adjusted to 70（equivalent to 6dB）. As a result, there are fewer complaints in the city and TCH disconnection ratio in the traffic statistic indexes decreases about 1%.

5.1.3 Conclusion

A good frequency plan is one of the important factors to keep the network operate properly.

As mentioned previously, the network quality can also be obtained with close multi-layer multiplexing mode (such as 12/9/8) and via careful planning.

5.2 Case 2（1X3 Frequency Multiplexing）

The following describes the use of 1*3 multiplexing mode with the Unicom GSM900 network in a certain place.

Unicom 900 frequency points：96～124 Configuration of carrier frequency：S3/3/3 BCCH carrier frequency layer：96～109 Multiplexing mode：4*3 TCH carrier frequency layer：110～124 Multiplexing mode：1*3



1）Sequence grouping plan

TCH is grouped in sequence. 3 cells of the same base station use the same HSN. Different stations use different HSN. All carrier frequencies on the same layer in the network use the same MAIO. Suppose the frequency hopping groups are allocated as follows:

Group 1：110 111 112 113 114

Group 2：115 116 117 118 119

Group 3：120 121 122 123 124

Take 1 for HSN of station A, MAIO of two carrier frequencies TCH1 and TCH2 of each cell are 0 and 2 respectively. Take 2 for HSN of station B, MAIO of two carrier frequencies TCH1 and TCH2 of each cell are 0 and 2 respectively, and so on. Thus, neighboring frequency is avoided among 3 different cells on the same station. Relative to TCH interval grouping, adjacent cells opposite to different stations are of less the possibility of collision. But, there is a possibility of collision of neighboring frequency among cells of different parallel stations relative to TCH interval grouping.

2）Interval Grouping Plan

TCH is grouped by interval. 3 cells of the same base station use the same HSN. Different stations use different HSN. Carrier frequencies on the same layer use the same MAIO. Suppose the frequency hopping groups are allocated as follows:

Group1：110 113 116 119 122

Group2：111 114 117 120 123

Group3：112 115 118 121 124

Take 1 for HSN of station A, MAIO of two carrier frequencies TCH1 and TCH2 of the cell of group1 are 0 and 2 respectively, MAIO of two carrier frequencies TCH1 and TCH2 of the cell of group 2 are 2 and 3 respectively and MAIO of two carrier frequencies TCH1 and TCH2 of the cell of group 3 are 4 and 0 respectively. Take 2 for HSN of station B and so on etc. Thus, neighboring frequencies are avoided among 3 different cells on the same station. Relative to TCH continuous grouping, adjacent cells opposite to different stations have the possibility of collision of neighboring frequency. But, there is no possibility of collision of neighboring frequencies between cells of different stations in parallel relative to the TCH interval grouping.

How to group TCH will reduce the interference of 1*3 frequency hopping. It can be said both continuous grouping mode and interval grouping mode have their own disadvantages. But, in the city center where concentrated base stations are distributed regularly, influence of neighboring frequency of the opposite adjacent cell is generally greater than that of the neighboring frequency of the parallel adjacent cell. The sequence grouping has obvious advantages. But, the use of interval grouping outside of the base station concentrated area is more useful for homogenizing the influence caused by the interference. Therefore, the local conditions should be taken into consideration when selecting the grouping mode. It is recommended to use sequence-grouping mode when the new channel allocation algorithm under close multiplexing mode is implemented. Thus, service quality of the whole network can be guaranteed.

6 Conclusion

A good frequency plan is got on the basis of proper cell planning (including station address, antenna direction, height, declination angle and transmitting power etc.). It can



be implemented effectively by adding DTX, frequency hopping, functional control ofup-link and down-link, well handover and channel allocation algorithm etc.



Appendix 1 Frequency Hopping

I. Several Concepts in Frequency Hopping

1. Frequency Hopping

Frequency hopping refers to that the mobile phone and base station receive and send information with a same frequency point. The frequency point sequence number is the hopping sequence number. A hopping sequence number (HSN) is an arrangement for determining all (N) frequency points only with HSN and mobile allocation index offset（MAIO）through a certain algorithm in the given frequency points set containing the number of N frequency points. The number of N channels on different time slots（TN） can use the same HSN. Different channels in the same time slot of the same cell use different mobile allocation index offset（MAIO）。

2. Frequency Hopping Mode

Frequency hopping mode is divided into the frame frequency hopping and time slot frequency hopping from the time domain concept and is divided into radio frequency hopping and base band frequency hopping from the implementation mode of carrier frequency.

Frame frequency hopping：Each TDMA frame’s frequency point changes once. In this mode, each carrier frequency can be considered as a channel. TCH in TRX carrier frequency where BCCH is located can not take part in frequency hopping when frame frequency hopping is used in a cell. Other different carrier frequencies should have different MAIO. It is a special example for time slot frequency hopping.

Time slot frequency hopping：Each time slot frequency point of each TDMA frame changes once. TCH in TRX where BCCH is located can take part in frequency hopping when time slot frequency hopping is used. But, it is implemented only when base band frequency hopping is used.

Radio frequency hopping：TX (Transmitting) and RX(Receiving) of TRX take part in the frequency hopping. The number of frequency hopping frequency points in the cell can exceed the number of TRX in the cell.

Base band frequency hopping：Each transmitter operates on a fixed frequency. TX doesn’t take part in the frequency hopping. It transmits the frequency hopping via the handover of base band signals. But the RX must take part in frequency hopping. Therefore, it is possible for the number of frequency hopping points in the cell to be greater than the number of TRX in the cell.

The current use of frequency hopping on Huawei equipment: BTS2.X mainly uses radio frequency hopping mode. It is recommended not to use base band frequency hopping mode. And the frame frequency hopping mode should be used for data configuration. BTS3.X can use base band frequency hopping, radio frequency hopping, time slot frequency hopping and frame frequency hopping. And the BTS3 X later than the version 0529 supports TCH of TRX where BCCH that uses the base band frequency is located to take part in frequency hopping (It is, of course, time slot frequency hopping).



II. Frequency Hopping Algorithm

1. Several Parameters

CA：Cell allocation Table，set of frequency sequence numbers used in the cell.

FN：TDMA frame number，which is broadcast on the synchronization channel. BTS and MS are synchronized via FN（0～2715647）.

MA：It is used in the set of wireless frequency sequence numbers of mobile station frequency hopping. It is a sub-set of CA. M includes the number of N frequency sequence numbers, 1 ≤ N ≤64.

MAIO: Mobile allocation index offset （0 ～N－1）. During the communication, wireless frequency sequence numbers used in the air interface is an element in the set MA. MAI（Mobile allocation index，0 ～N－1） is used to specify a specific element in the set MA. In other words, the frequency point used is specified by MAI. MAIO is an initial offset of MAI. It is used to prevent multiple channels from holding the same carrier frequency simultaneously.

HSN: Hopping sequence number （Generator）（0 ～ 63）；It is cyclic frequency hopping when HSN=0. And it is random frequency hopping when HSN≠0.

2. Frequency Hopping Algorithm

The related parameters can be set properly to make the system in optimum operating state only when you know the actual functions and concept of frequency hopping of each parameter in the frequency hopping algorithm. The following is the flow chart for calculating the actual operating frequency of the carrier frequency in each frequency hopping time slot. Where, MAI=（S+MAIO）MOD N RFCHN=MA（MAI）；S is got via calculating according to the frame numbers and hopping sequence numbers. MAI is the number of carrier frequencies actually allocated via S plus hopping frequency offset.



FNT1 (0...2047)

HSN(0...63)

FNT3 (0...50)

MAIO(0...N-1)

MA(m0...mN-1)

FNT2 (0...25)

Represent in 7 bits

5 bits

T1R =T1 MOD 64

11 bits

6 bits

6 bits

Exclusive OR

6 bits

Addition

7 bits

Look-up table

6 bits

7 bits

7 bits

Addition

8 bits

M' = M MOD 2^NBIN

NBIN bits

M' < N YN

S = M'S = (M' + T) MOD N

T =T3 MOD 2^NBIN

NBIN bits

NBIN bits

MAI = (S + MAIO) MOD N

NBIN bits

RFCHN = MA (MAI)

RFCN

NBIN bits

where NBIN = INTEGER((Log base 2 of N) + 1) MOD = MODULO ^ = raised to the power of

Figure2 Frequency hopping algorithms

III. Overview of Frequency Hopping Data Configuration

1. HSN (Hopping Sequence Number）

Location：Data Table of frequency hopping

Range of values: 0～63. 0 indicates cyclic frequency hopping（0 is forbidden for some equipment），other values indicate pseudo random frequency hopping. In principle, all channels of all carrier frequencies of the base station which may have the same and neighboring frequencies should use the same HSN so as to make different carrier frequencies free from collision of the same and neighboring frequencies by setting MAIO properly. As it can not be guaranteed that different base-stations use the consistent frame numbers, HSN of different base-stations should be made different as far as possible. Especially when the same frequency hopping group is used, possibility of collision can be minimum only when HSN is different.

2. TSC（Training Serial Code）

Location： Frequency hopping data Table

Range of values：0～7；The value must have the same color as that of the base station.



3. MA（Mobile Allocation Set）

Location：Carrier frequency configuration Table

Range of values：0～64；MA is the set of frequency hopping points of frequency, which is composed by 64 frequency points in max. The frequency point sequence numbers must be contained in CA Table（Cell allocation Table）.

4. MAIO（Mobile Allocation Index Offset）

Location：Wireless Channel Configuration Table

Range of values：0～（N－1）；Where, “N “ is the number of frequency points contained in MA. Frequency hopping mode supported by the base station should be considered when planning MAIO. Try to avoid the collision of the same and neighboring frequencies under the same cell of the same base station.

5. CA （Cell Allocation Table）

Range of values：0～64；All frequency points in the cell should be contained in it, and it should be allocated continuously from the parameter “Valid Frequency Point 0”, no empty data item should exist.

6. Frequency Hopping Mode

Location：Cell configuration data Table

Range of values：no frequency hopping, base band frequency hopping and radio frequency hopping. Select them according to the support of base station and the actual requirements.



Appendix 2 Concept of Synchronization Cell

Concept of synchronization cell is very important for establishing frequency hopping strategy and reducing interference in the network effectively. BTS and MS are synchronized through the convention of frame number.

1. For base station equipment of our company, frame numbers of various cells in the same base station are generated by the main clock generator（MCK or TMU）. And they don’t use the frame number offset technique of different cells of the same base-station. All frame numbers are the same. Therefore, when different cells of the same base-station share the same MCK or TMU generator, they can be treated as synchronization cells. The base-station supports the synchronization cell in the following way:

Max. synchronization base-station type of BTS2 X: S6/6/6. Max. synchronization base-station type of BTS30: S18/18/18, the frame is

generated by one of the TMU. The max. base-station type S6/6/6 in the case of one TMU（the combination of three cabinets）.

Max. synchronization station type of BTS312: S24/24/24, one TMU manages S8/8/8, S24/24/24 is managed by 3 TMU, but the frame No is only generated on one TMU.

The frame number is generated by one of the TMU. The max. synchronization station type is S8/8/8 in the case of one TMU（the combination of two cabinets）.

2. In synchronization cells, the same HSN can be used in different frequency hopping groups since frame numbers used by each TRX in each cell are completely the same. Set MAIO properly to avoid collision of neighboring frequencies in various cells of the same base-station and within the cells.


Frequency Planning Theory 20010323 B 1.0

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