gsm9001800 bss&pcu network planning data configuration specification(v3.1)

GSM9001800 BSS&PCU Network Planning Data Configuration Specification(V3.1)

Huawei Technologies Co., Ltd.

Wireless Planning & Design Dept., International Technical Support DivisionDocument NumberProduct VersionConfidential Level

3.1secret

Product Name: GSM900/1800149 pages

GSM900/1800 BSS&PCU Network Planning

Data Configuration Specification

(Version 3.1)

(For Internal Use Only)

Written by:Technical Support Group Wireless Planning and Design Dept.Date:2002/3/14

Reviewed by:Date:

Reviewed by:Date:

Approved by:Date:

Huawei Technologies Co., Ltd.All Rights Reserved Revision Record

DateRevised versionDescriptionAuthor

2000/9/101.00Draft completedHequn, Zhao Yinghe. Tao Maodi and Xing Lijin etc.

2000/10/102.00First revisionZeng Shuhui and Li Yunzi etc.

2000/10/202.00Revision completed; ready to issueZhao Qiyong

2001/1/22.10Revision completed; ready to issueZeng Shuhui and Zhao Qiyong

2001/3/82.20RevisionZeng Shuhui

2001/7/253.00RevisionSi Fazhong, Zeng Shuhui and Chen Jing

2001/12/203.10RevisionChen Jing, Si Fajing, Li Xia and Bai Xiaobin

51. Foreword

61.1 Types of wireless parameter adjustment

61.2. Prerequisites for wireless parameter adjustment

71.3.Points for attention in wireless parameter adjustment

7II. Data configuration

72.1 Local office

112.2 Sites

132.3 Cells

542.4 Handover

822.5 Power control

1012.6 Channels

111III. GPRS (PCU) network planning data configuration specifications (draft)

121IV.Accessories

1214.1The channel description format and cell frequency configuration

1244.2 Location area classification basic principle

1244.2.1 LAC concept

1244.2.2 Principles in location area classification

1264.3 34 Tables (BSC) of Network Planning Data

1284.4 Description of parameter configuration and main check-points for Phase XX network planning of the XX mobile network

1304.5 Description of flow control (based on the 06.0520 version and the current 01.07.0520 version)

1304.5.1 BSC internal flow control

1354.5.2 Cell traffic level maintenance and processing at different traffic levels

1384.5.3 About TCH flow control

1384.6 Newly added functions in new version

1424.7. Description Manual of Key Specifications in Various Versions of GSM BSC32 Traffic Statistics

1424.7.1 Overview

1424.7.2 Traffic statistics modification of various versions

1454.8 Description of data configuration for BCCH participation in frequency hopping

GSM900/1800 BSS&PCU Network Planning Data Configuration Specification

(Version 3.0, Dec 20, 2001)

Key words: BSS function applications

Abstract: this article describes the specifications and the points for attention that should be followed in the process of GSM900/1800 BSS network planning data preparation and optimization. On basis of the first edition, related functions and parameters of BSC0520 version and BTS3.X are added. Network Planning Data refer to all functions and algorithm parameters related to the wireless network quality (voice, data, etc.) in the BSS system. With the perfection of the BSS system and the application of GPRS and next generation system, more functions and algorithm parameters will be continuously added. So, when the Central R&D Division of Huawei adds or improves any functions and algorithm to the BSS system, please inform our department in time so that we can participate in the evaluation and discussions. Besides, the personnel in charge of network planning of this project also has the final say in on-site modification of such data. Research into wireless network parameters and improvement of algorithms and functions must also forecast hidden hazardous factors in wireless networks (e.g., large traffic and user abnormal behavior), and should not narrow down to existing small networks. Otherwise, it will cost a more dear price for compensations when problems pop up during construction of larger networks.

Moreover, no parameters stand alone. Many problems and phenomena on the network result from the joint action of function algorithms and the way of organizing the wireless networking. For such complicated phenomena, we should integrate our theoretical study with practical experience, and make comprehensive and profound case studies, from all aspects such as MSC, BSC, and BTS as well as wireless network characteristics. Our analysis should involve perfect suggestions for device function algorithms, application suggestions for function algorithms in actual networking, and guide to problem analysis. This is even more urgent while Huawei devices are getting more and more reliable, but the wireless network is getting more and more complex, and traffic and capacity are getting greater and greater. As a result, it gets more and more complicated to make comprehensive use of such parameters in consideration of wireless network features. Thus, This needs the participation of all of usSome topics worthy of further research have also been mentioned in the article.

List of abbreviations:

List of Reference Documents

NameAuthor Code Issuing dateReference location

First version of the specifications2000/8

GSM related protocols

Central R&D documents

Technical documents of other manufacturers

Others

Revision Description:1).This revision is made on basis of Version 2.2. It includes some updating of part of original parameters, and addition of new BSC concentric functions, channel generation II distribution algorithms, flow control functions, extended cells, and BCCH parameter configuration and introduction that participate in the frequency hopping function. Moreover, it also lists the main functions of Huaweis mainstream BTS, BSC and traffic statistics. Meanwhile, it has also briefly described part of GPRS parameters in PCU. Parameter setting is on basis of thoroughly understanding the algorithms behind the parameters. Only in this way, can we arrive at correct applications for different circumstances. The recommended values are for reference only. Please come up with better and more mature ideas and suggestions in the implementation process.

2) The module number and cell number in the cell, handover, and power control menus act as indexes of a cell in a BSC. The module number must start with 1 and must correspond to the BM code; the cell number falls in the value range 0127, and must be unique in a module. In earlier versions, these codes must be continuous. The base station codes have a value range of 063, and must also be unique in a module. For easier extended and workload reduction during network optimization, each base station is assigned three cell numbers; if there are enough device resources, each cell that has extended potential can be assigned with more carrier numbers, e.g., all single carrier sectors are configured into 2 carrier sectors.

3) Based on the two points above, the data setting center should please work out corresponding modifying plans.

1. Foreword

The 900/1800MHzTDMA digital cellular mobile communication system (GSM) is an integrated system that integrates such fields as network technology, digital SPC switching technology, all types of transmission technologies and wireless technologies. Normally, the GSM system can be divided into three parts analyzed from the physical structure of the network, i.e., the network can be divided into the network subsystem (NSS), the base station subsystem (BSS), and the mobile station (MS). But analyzed from the signaling structure, the GSM system largely consists of the MAP interface, the A interface (interface between MSC and BSC), the Abis interface (interface between BSC and BTS) and the Um interface (interface between BTS and MS, which is normally called the air interface). All these entities and interfaces have plenty of configuration parameters and performance parameters, some of which are already determined during the device developing and manufacturing stage, but most of which are determined by the network operators according to the actual network requirements and actual running. But the setting and adjustment of those parameters have considerable influence on the operation of the whole GSM network. So, GSM optimization is in a certain sense, the process of optimization setting and adjustment of all types of parameters in the network.

As a mobile communications system, the GSM network has parameters related to wireless devices and interfaces that are most sensitive to the influence of network service performance. The wireless parameters in the GSM network refer to parameters related to wireless devices and wireless resources. These parameters have vital impact on the cell coverage in the network, the distribution of signaling flow and the service performance of the network. As a result, reasonable adjustment of wireless parameters is an important part of GSM network optimization. Normally, the GSM wireless parameters can be divided into two types according to the service targets of the wireless parameters in the network, i.e., project parameters, and resources (cell) parameters. The project parameters refer to those related to project design, installation and commissioning, e.g., antenna height, antenna direction, antenna gain, antenna declination angle and cable attenuation. These parameters must be determined during network design, as they can hardly be modified during network operation. The resources (cell) parameters refer to those related to the configuration and usage of wireless resources. They are normally transmitted on wireless interfaces (Um) to keep the consistency between the base station and mobile stations. Another important feature of resources parameters is that most resources parameters can be dynamically adjusted during network running at some man machine interfaces. The wireless parameters involved in this text are mainly wireless resources parameters (unless otherwise particularly specified, the wireless parameters described here actually refer to wireless resources parameters).

When a service carrier starts to construct a mobile communications network, he must first make system project design according to such parameters as wireless channel features obtained from the geographic environment of a specific area, and the service forecasting and testing. The design should include network topology design, base station addressing and frequency planning. But compared with a fixed system, as user terminals are mobile in mobile communication, so, mobility, spontaneity, and randomness are obvious features of not only service flow, but also signaling flow, and other characteristic network parameters. Such features explain why there is some big difference between the design of mobile communication systems and their actual applications in such aspects as the traffic model and signaling flow. So, after the network starts running, the carrier needs to adjust the various types of structures, configurations and parameters of the network, so that the network can work more reasonably. The is an important part in the whole network optimization process.

Wireless parameter optimization adjustment is a process of enhancing the communication quality, improve the average network service performance and increase the device utilization rate of a running system according to the actual wireless channel features, traffic features, and signaling flow bearing, and by adjusting the partial or global network wireless parameters. In fact, the basic principle of wireless parameter adjustment is to make full use of existing wireless resources, average and smoothen the global service flow and signaling flow through load-sharing, so as to reach the goal of enhancing the average network service level.

1.1 Types of wireless parameter adjustment

There are two types of such adjustment according to the property of problems to be solved through wireless parameter adjustment. The first type is to solve static problems, i.e., modify the traffic model adopted in system design according to the actual average traffic flow and signaling flow tested on site in various areas in the network, so as to solve the rampant problems in the long run. The other type of adjustment is used to solve problems of traffic overloading and channel congestion in certain areas within a time segment due to some spontaneous or random events.

For the first type of adjustment, the carrier only has to make periodic tests and reports on the actual running of the network, and on this basis, make appropriate adjustment of global or partial network parameters and configurations. But the second type of adjustment means that the network operator should adjust part of the real-time wireless parameters according to the data obtained by the testing personnel. However, no matter what type of wireless parameter adjustment is used, it means the same for the parameters themselves. So, this manual starts from parameters, and makes analysis of the impact of parameter adjustment range and adjustment result on the whole network. It does not involve the real time issue during adjustment.

1.2. Prerequisites for wireless parameter adjustment

The network operator must first have a thorough understanding of the meaning of each wireless parameter, the adjustment mode and adjustment result, and should be very experienced with the wireless parameter types involved in problems that occur in the network. This is a necessary condition for effective wireless parameter adjustment. On the other hand, the adjustment of wireless parameters will depend on plenty of actual testing data obtained during actual network operation. Normally, these parameters can be obtained in two ways. First, the statistic parameters can be obtained from the operation maintenance center (OMC) of the network, or the operation maintenance center (OMCR) in the radio segment, e.g., the bearing of CCCH channels, RACH channels and the signaling bearing of other channels (including wired and wireless channels). Second, other parameters, including cell coverage, mobile station communication quality, etc., should be obtained from actual measurements and tests. So if the carrier wishes to effectively adjust wireless parameters, they must make frequent and long-term measurements of the various network features.

1.3.Points for attention in wireless parameter adjustment

In the GSM system, plenty of wireless parameters are set on basis of cells and regional areas. But inter-region parameters are often strongly interrelated. So, during parameter adjustment, consideration must be made to the impact of regional parameter adjustment on other areas, especially adjacent areas. Otherwise, parameter adjustment will bring about diverse consequences.

Besides, when regional problems occur in the network, first we should determine whether they are caused by device faults (including connection failure). Only when it is confirmed that network problems are caused by service causes, can we make wireless parameter adjustment. The wireless parameter adjustment modes recommended in this manual are put forward on condition that no device problems exist.

II. Data configuration

2.1 Local office

BSC cell tableCell system type: Huawei M900/M1800 BSC supports both the independent and hybrid networking of both 900M and 1800M. The setting here can be either "GSM900" or "GSM1800" according to the band configuration selected for the cell or the network.

Sub cell type and cell level: to determine the location of a cell in the layered and hierarchical structure, used mainly for dual-band networking, so as to differentiate macro-cell, micro-cell, and better realizing load-sharing and handover. The setting here is "normal" and "superior" during the construction of a new network.

BCC and NCC: NCC and BCC form BSIC.

Value range: 07

BCC is a base station color code used to distinguish adjacenting cells with the same BCCH frequencys; in frequency hopping cells, the TSC in the frequency hopping data table must be configured to be consistent with BCC in the cell.

Note: after dynamic modification of cell BSIC, TSC in the frequency hopping data table must be modified accordingly.

The NCC is a network color code used to distinguish networks in different areas. It is coded in a uniform way over the whole country.

Value range: 07

Cell Global Identifier: CGI, must be capitalized; notice that the classification of LAC has a very important effect on increasing signaling load and call completion rate.

For the basic principles of LAC classification, refer to the appendices.

Supporting GPRS

Value range: Yes, No

Unit: None

Content: indicating whether the GPRS function is supported. The GPRS function needs the support from the base station.

Recommended value: to be determined according to the actual circumstances. For base station versions that don't support the GPRS function and cells where the GPRS service is not commissioned yet, the value must be set to No; otherwise, it might make it impossible for part of the mobile phones to access the Internet.

Frequency hopping data table Frequency hopping index number: internal index number, provides an association between the wireless channel configuration table and the frequency hopping data table.

MA: the MA is a set of frequency hopping points formed by a maximum of 64 frequencys; the frequencys must be those within the cell distribution table. At present, when carrier frequencies hop in the radio frequencies, MA can not contain the frequencys on the BCCH channel; BTS3X after the 03.0529 version supports BCCH participation in frequency hopping (baseband and time slot frequency hopping). Thus, except the time slot 0 of hopping carrier frequencies (when extended BCCH is configured, the time slots corresponding to the extended BCCH should be also excepted), MA in other time slots can contain the BCCH frequency; in actual use, note that only BSC08.0520B and subsequent versions support BCCH participation in frequency hopping.

The data configuration method of BCCH participation in baseband time slot frequency hopping, refer to the appendix (4.8 Description of data when BCCH participates in frequency hopping)

Hopping frequency offset MAIO: during frame frequency hopping, MAIO is recommended to the same in all channels of a TRX, in the same cell, the MAIO of a different TRX is different, and the rule of the thumb here is to guarantee that the MAIO in the same time slot of TRX of the same HSN and MA in synchronized cells are not the same, so as to avoid clash between the same frequency. During time slot frequency hopping, the MAIO of various channels of the same TRX can be configured differently.

Note: BTS2.X supports radio frequency frame hopping; all versions of BTS3.X support baseband frequency hopping and radio frequency hopping frequency, including time slot frequency hopping and frame frequency hopping; but only BTS3.X after version 03.0529 supports BCCH participation in frequency hopping (baseband and time slot frequency hopping)

Hopping serial number HSN: the HSN of all channels in the same cell is recommended to be the same; and it is specified that HSN can not be "0". For part of the 30 base station versions, if HSN is configured to be "0", it will cause base station to be unable to properly operate.

Training serial code TSC: when frequency hopping in a cell, TSC must be set to be identical with the BCC in the cell, otherwise, the TCH carrier channels in the cell cannot be properly seized.

Note: for frequency hopping algorithms, refer to Protocol 0502

Wireless channel configuration tableChannel type: indicating the channel type and function of every time slot of all carrier frequencies in a cell.

Every cell is configured a BCCH carrier; normally, the TRX corresponding to a BCCH frequency is fixed to be the smallest TRX number in the cell. Listed below are the common channel combinations of BCCH carrier frequencies: Combination BCCH7TCH

Main BCCHSDCCH/8+6TCH

Main BCCH2SDCCH/8+5TCH

Main BCCHSDCCH/8+ extended BCCH(BCH)+5TCH

Main BCCHSDCCH/8+ extended BCCH(BCH)+TCH+ extended

BCCH(BCH)+3TCH

Note: the configuration of BCCH in a cell should be done appropriately according to the channel number in the cell and the paging capability in the location area.

The main BCCH and combined BCCH are configured in time slot 0, and extended BCCH channel can be configured only in time slots 2, 4, and 6. After extended BCCH channels are configured, the CCCH configuration parameters in the system message data table should be configured accordingly. For example, if an extended BCCH is configured in time slot 2, then, in the system message data table, CCCH should be configured into 2 non-combined CCCHs.

All versions of BTS3.0 base station running on the network at present support extended BCCH, but only version 05.0420 and those after of BTS2.0 base station support extended BCCH.

If there is the cell broadcasting function, SDCCH8 can be modified into SDCCHCBCH. At present, devices support only one CBCH channel in each cell, with the channel type of SDCCHCBCH, but they don't support BCH+CBCH. In practice, traffic statistics must be continuously made so as to monitor the seizure of each channel and make timely adjustments in order to reach the maximum utilization of channels.

Recommended value: for 1 to 2 TRXs, one SDCCH/8 is configured; for 3 to 4 TRXs, 2 SDCCH/8s are configured; for 5 to 6 TRXs, 3 SDCCH/8s are configured. Meanwhile, start the dynamic SDCCH distribution function to guarantee ideal operation.

flow control parameter table:

At present, the on-line BSC versions all support flow control. The flow control parameter table at the data management console is a hidden form. To set corresponding parameters, please refer to the flow control guidebook of corresponding versions (with permission of version administrators).

Take the 01.07.0520B version as example, the operation is as follows:

Enter the data management console. Press CTRL+SHIFT+F12, open the "flow control parameter table", and confirm the following information:

"Internal flow control permission" configured as: "Yes"

"Message queue initial overload threshold" configured as: "70"

"Message queue severe overload threshold" configured as: "60"

"Inter-module messages allowed within a cycle" configured as: "15"

"Observation cycle (unit: tick)" configured as: "25"

Note:

1. Starting from G3BSC32.1010X.06.0520B, flow control table 2 under the configuration menu and flow control table 1 under the local office menu are integrated into one and is put under the configuration menu, with some new fields added; meanwhile, flow control table 1 under the local office menu is deleted.

2. G2BSC32.1010X.03.0520B X=1, 2, and 3, able to start the flow control function;

3. G3BSC32.10102.04.0520B can start the flow control function;

4. G3BSC32.1010X.06.0520B X=0, 1, and 2, able to start the flow control function;

5. 00.07.0520B cannot be used temporarily;

6. 01.07.0520B and subsequent versions can start the flow control function.

2.2 Sites

carrier configuration tablePower level: "0" power level shows that power is in its maximum.

1. In BTS version:

The 0407 version of BTS30 base station supports static power level setting of levels 06, and the 0529 version supports the static power level setting of levels 010, and in the 04.0529 version, the down-tuning function by 30dB (in maximum) is added, for debugging before cutover (operated on the base station maintenance station);

All on-line versions of BTS20 base station support the static power setting of levels 010;

The Micro cellular base stations support the static power setting of levels 013.

Note:

1. Cells can be enabled to sufficiently absorb traffic by setting the "power level" parameters; but when antennas are too tall that result in serious cross-cell overlapping, the first solution should be lowering the antenna height and increasing the antenna declination angle. Also note that lowering base station transmitting power will deteriorate indoor coverage.

2. The available frequencys must be the subset of the CA table

3. Normally, for cells with the same priority in the network, their power level setting should guarantee that the EIRP of every cell is basically the same.

4. During power level setting, note that for different carrier frequencies in a cell, different combining modes will arrive at different loss.

5. In case there is no frequency hopping, among all the available frequencys of all carrier frequencies in the carrier configuration table, only the first frequency is valid, and no others have any impact.

carrier power type

Value range: "40W", "60W", "default"

Default value: "default"

Content: for configuration of the carrier type; and after the launch of 60W TRX, this parameter should be used to distinguish carrier frequencies with different power.

Concentric property

Value range: internal circle, external circle, none

Default value: none

Content: to indicate whether carrier frequencies should be configured on the internal or external circle of a concentric circle.

TRX priority class

Value range: level 0level 7

Default value: "level 0"

Content: used in Huawei channel II distribution algorithm to designate the priority of TRX.

Feeder configuration tableWhether there is tower amplifier

Value range: with tower amplifier, without tower amplifier

Power attenuation factor

Value range: 0255

Recommended value: to be reasonably configured according to the feeder length, the method of which is shown as follows.

Use BTS base station (including 2.0 and 3.0 base stations) of the CDU system to adjust the gain of CDU according to the two parameters described above.

In systems where BTS2.x base station adopts the combiner/divider mode (no CDU mode), this has been fixed at 10.

Uplink: according to actual tower amplifier circumstances:

Data configurationWith or without tower amplifierPower attenuation factorDescription

With tower amplifierWith tower amplifierTower amplifier gain -feeder loss =12-4=8 (i.e., CDU attenuation of 8dB)Triplex tower amplifier has a gain of 12.

Duplex tower amplifier has a gain of 14

Simplex tower amplifier has a gain of 14

Assuming that feeder loss is 4dB

No tower amplifierNo tower amplifier0

Downlink: no tower amplifier, and power attenuation factor is set to be 255 (no impact)

2.3 Cells

System message data tableSystem message used

Value range: this is a multi-option item including system messages 112. 2bis, 2ter, 5bis, 5ter and 10bis

Unit: None

Content: System Information Used, used to determine whether to send a certain type of system message. A system message is one sent from the network side to a mobile station in the broadcast mode. It informs all mobile stations of information about a location area, a cell, available carrier frequencies, available frequency hopping sequences, channel distribution and random access control, so as to help mobile stations to locate network resources quickly and accurately. In the pull-down check-box, select the system message type supported by BSC system. If one is selected, it means that it is supported, indicated by "1"; otherwise it is "0". From top to bottom, the system message types are: 10bis, 5ter, 5bis, 2ter, 2bis, 12. , 1. For example: 10000000000000000 indicates that only the system message type 10bis is supported. Besides, the system message types 2bis and 5bis are used for the 1800 network, and the system message types 2ter and 5ter are used for the 900/1800 dual-band network. For detailed system message definitions, refer to Protocol 0408 and system message training materials.

Recommended value: select system messages: 16. 2bis, 2ter, 5bis, 5ter

Note: versions after G2BSC3203.0520B send the following system messages in default: 1, 2, 2ter, 3, 4, 5, 5ter, and 6; for some new system messages (e.g., messages 7 and 8), some mobile phones do not recognize them, which can easily cause automatic resetting or other abnormal occurrences. So care is requested during data configuration. Moreover, after dynamic system message modification, we must reset the baseband processing board at BTS2.X base station (including the 22C microcell), but BTS3.X base station does not need to be reset.

Timed sending


Unit: None

Content: showing whether BSC periodically updates the system message content sent from BTS. If it is set as "Yes", BSC will send system messages to BTS periodically (interval to be determined by the sending interval), otherwise, manual sending is requested.

Recommended value: Yes

Timed sending interval

Value range: 0255

Unit: minute

Content: specifying the interval BSC sends system messages periodically to BTS.

Recommended value: 10

Maximum MS re-transmitting times

Value range: 1, 2, 4, 7

Unit: times

Content: MAX retrains, the upper limit of times MS is allowed to send the "Channel Request" message in the same immediate assignment process. After MS initiates the immediate assignment process, it will keep monitoring BCCH and all public control channel messages belonging to the CCCH group to which it belongs. If the network side does not send an Immediate Assignment or Immediate Assignment Extend message, MS will keep re-sending the channel request message after a certain interval. The greater this parameter is set to be, the higher the success trial call rate, and the high the call completion rate, but also the greater the load on the RACH channel and the SDCCH channel. Refer to Protocol 0408.

Recommended value:

For areas where cells have the radius more than 3 kilometers but with less service traffic (normally the suburbs or rural areas), M can be set as 11 (i.e., the maximum re-sending times is 7) so as to raise the mobile station access success rate.

For areas where cells have the radius less than 3 kilometers but with average service traffic (normally the urban areas where traffic is not so busy), M can be set as 10 (i.e., the maximum re-sending times is 4).

For microcells, M is recommended to be set as 01 (i.e., the maximum re-sending times is 2).

For microcell areas and obviously congested cells M is recommended to be set as 00 (i.e., the maximum re-sending times is 1).

It is recommended to set satellite transmission base stations as 4 or greater. Note: when the downlink quality is poor, it will cause a mobile phone to send SABM to BTS multiple times.

Common access control level

Value range: multi option item, including level 0 barred, , level 9 barred

Content: used for load control, allowing or inhibiting network access to some users at the common access level. "1" indicates that access is barred, and "0" indicates that access is allowed. For example: 1000000000 means to allow network access to users except those at level 0. During base station installation and commissioning or during maintenance testing of some cells, it can be set as "1" for all, so as to compulsorily inhibit access of different users, and to reduce impact on installation or maintenance; in cells with a heavy service traffic, congestion will occur in busy hours, indicated by a higher RACH clash frequency, AGCH flow overloading, and Abis interface flow overloading. Setting the level of some users as "1" can reduce the service traffic in the cell.

Recommended value: all set to "0"

Special access control level

Value range: multi option item, including level 11 barring, , level 15 barring

Content: used for load control, allowing or inhibiting network access to users at certain some special access level. "1" indicates access barred, and "0" indicates access allowed. in cells with a heavy service traffic, congestion will occur in busy hours, indicated by a higher RACH clash frequency, AGCH flow overloading, and Abis interface flow overloading. Setting the level of some users as "1" can reduce the service traffic in the cell.

Recommended value: all set to "0"

Cell channel description format

Value range: bitmap, 1024, 512, 256, 128. variable-length

Content: the message element is in fact a list of available absolute carrier numbers in a service cell, with the length of 17 bytes. To be specific, there are altogether 124 bits starting from the D3 bit of the second byte in the cell channel description to the D0 bit in the 17th byte, recorded respectively as carrier frequencies No. 124, 123, 122......3, 2, and 1. If the Nth bit is 1, then this Nth carrier belongs to this cell. At present, this parameter does not function in the system.

Attach/detach allowed


Content: Attach-detach allowed, ATT. For different cells in the same location area, ATT must be set to be the same. When it is set to "Yes", it will facilitate the network no longer to process the called connections of this user when the MS switches off, thus, saving the network processing time and resources.


Power control allowed


Unit: None

Content: indicating whether MS should remove the level received from BCCH carrier time slots when it calculates the average receiving level grade value, if BCCH carrier time slots participate in frequency hopping.


Discrete transmitting indication

Value range: can be used, must be used, must not be used

Unit: None

Content: indicating the discontinuous uplink transmission of MS in the past measuring cycle; refer to Protocol 0508.

Recommended value: must be used

Note: versions starting from version G3BSC32.10101.01.1120A support control as to whether to activate the downlink DTX function in BSC; for parameter setting, refer to "Whether to use downlink DTX" in the cell property table.

Cell access allowed

Value range: Yes (0), No (1)

Unit: None

Content: cell access barred (CELL BAR ACCESS); refer to Protocol 0408. It can be used together with CBQ to determine the priority of cells.


Cell barring allowed

Value range: Yes (1), No (0)

Unit: None

Content: CBQ (Cell Bar Qualify). CBQ affects only cell selection, and does not affect cell reselect. Together with CBA, it forms the cell priority. Refer to Protocol 0408.

Cell barring allowedCell access and allowed Cell selection priority Cell reselect priority

No Yes Normal Normal

No NoBarred Barred

Yes Yes Low Normal

Yes No Low Normal

Recommended value: None

Emergency call allow


Unit: None

Content: EC (Emergency call). For MS at access level 09, EC set to "Yes" indicates Emergency call allowed; for MS at access level 1115, only when the corresponding access control bit and EC are both set to 0, is Emergency call barred.


Call re-construction allowed


Content: RE. The network determines by setting RE whether to allow call re-set up. As sudden interferences or high buildings can cause "blind points" that result in call disconnections caused by wireless link faults, MS can start the call re-set up process to restore the call. Allowing call re-set up can reduce the average calldrop rate, but it also takes a longer time. This applies to suburbs or urban areas with a bad coverage.


Nation color code NCC allowed

Value range: multi option item, including allowed selections 07

Content: NCC allowed, sent in system messages 2 and 6. It lists the combinations of cell NCC codes MS should measure. For measuring reports where the parameter is "1", MS will report it to the base station. Note: as MS cannot report adjacent area information in networks where NCC is set to 0, if this parameter is set impropriety, it will cause MS unable to initiate normal call handover in the calling status, which results in cross-cell calldrop. Refer to Protocol 0508.

CCCH configuration

Value range: 1 non-combined CCCH, 1 combined CCCH, 2 non-combined CCCHs, 3 non-combined CCCHs, 4 non-combined CCCHs; in a corresponding BCCH multi frame, number of CCCH message blocks: 9, 18, 27, and 36. CCCH configuration determines the capacity of PCH, AGCH, and RACH. In particular, the capacity of PCH should be considered with care. Normally, the PCH capacity of all cells in a LAC should be guaranteed consistent, or, at least the cell with the least PCH capacity should bear more carrier frequencies than the sum of all carrier frequencies under LAC.

Unit: None

Recommended value: for cells with one carrier, it is recommended to configure 1 combined CCCH (in a system in the location area with few call messages); for the rest, determine the CCCH configuration according to the carrier number. For extended BCCH (including the main B and expanded BCCH), if several BCCH channels are configured, we should then configure several non-combined CCCH.

Extended transmission time slot number:

Value range: 312, 14, 16, 20, 25, 32, and 50

Unit: RACH time slot number (corresponding to a TDMA frame, 4.615ms)

Content: the Tx-integer, used to calculate the time slot number during each interval of sending when MS continuously sends multiple channel request messages. It is set to reduce the number of clashes on the RACH channel, and it mainly affects the execution efficiency of immediate assignment processes. The value of this parameter is related to the CCCH configuration mode, as they two together determine the parameter S.

Tx-integerS

CCCH not sharing with SDCCHCCCH sharing with SDCCH

3. 8. 14. 505541

4. 9. 167652

5. 10. 2010958

6. 11. 2516386

7. 12. 32217115

The time slot number between the time when MS starts the immediate assignment process and the time when the first channel request message is sent (don't includes the time slot of sending message) is a random value in the set {0, 1. , MAX(T, 8)1};

The time slot number in the interval between any two adjacent channel request messages interval (not including the time slots sending the messages) is a random value in the set {S, S1. , ST1} .The greater T gets, the greater the variation range of the interval for MS to send channel request messages, but the less the RACH clashes. The greater S gets, the greater the interval for MS to send channel request messages, the less the clashes on the RACH channel, and the higher the availability rate of AGCH and SDCCH channels. But the increase of the two will lengthen MS access time, which leads to drop in the access performance of the whole network. So normally, T should be chosen to make S as small as possible (so as to reduce MS access time), but we must guarantee that no overloading occurs on the AGCH and SDCCH channels.

Recommended value: 20 (it can be greater if the cell immediate assignment has a low success rate) (32 for satellite transmission, so as to reduce impact of satellite transmission delay)

Note: in case of a heavy network traffic, the less the S+T value, the lower the immediate assignment success rate in the cell access performance measuring task; in this case, we can adjust the T value so that S+T is greater.

Access allowed reserved blocks

Value range: 02 (1 combined CCCH), 07 (others)

Unit: Block

Content: the BS-AG-BLKS-RES, indicating how many message blocks in the CCCH channels are reserved specifically for access allowed channels. After CCCH configuration is done, this value actually shows the seizure rate of AGCH and PCH assigned on CCCH. The setting of this parameter will affect the time MS responds to paging and system service performance.

Recommended value: 2 (non combined CCCH), 1 (combined CCCH)

Note: the AGCH processing process of BTS30 program is the same with BTS20. When the AGCH channels are all seized, if the PCH channel is idle, it can be used to issue immediate assignment commands. If the reserved AGCH blocks are configured 0, then immediate assignment can be sent only on idle call channels; so, some fixed capacity should be assigned to AGCH.

Coding of frames between the same calls

Value range: 29

Unit: multi frame per cycle

Content: BS-PA-MFRMS, meaning how many multi frames are taken as a cycle for a paging sub-channel. In fact, this parameter determines how many paging sub-channels are paging channels in a cell divided. In an actual network, MS monitors only its paging sub-channels and ignore the content of other paging sub-channels. Refer to Protocol 0502, 0508. The greater the parameter MFR, the more paging sub-channels in a cell, and correspondingly the less the users belonging to each paging sub-channel (refer to the 05.02 paging group calculation mode in the GSM specifications), which can lengthen the average MS batteries time. But the greater the MFR, the greater the delay of paging messages on the air segment, and the lower the average system service performance. The selection of this value is based on the principle of guaranteeing that no overloading occurs on this paging channel, and on this basis, the parameter can be as small as possible. In the running network, we should measure the overloading of paging channels, and take this as the basis to appropriately adjust the MFR value. Because any paging message in the same location area (with the same LAC) must be sent in all cells in this location area, so the capacity of each paging channel in this location area should be made the same or as close as possible (i.e., the paging sub channels in each cell calculated finally).

Recommended value: BTS3X 2

For BTS2X, reference the following recommendation

MFR is set to 6 or 7 (i.e., with 6 or 7 multi frames taken as the cycle of paging groups) for areas with an average or great paging channel load (usually in location areas with medium or great traffic); for areas with a small paging channel load (usually areas with a small traffic), MFR is set to 4 or 5 (i.e., 4 or 5 multi frames are taken as the cycle of paging groups); normally, it is set to 2.

Note:

1. A call block (four continuous CCCH time slots) can bear 2 IMSI calls or 4

TMSI calls or a AGCH immediate assignment message.

2. The downlink signaling link fault When IDLE

The downlink fault rule is based on the downlink signaling link fault timer DSC. When a mobile phone sits in a cell, DSC is initialized into an integer closest to 90/N (N is BS_PA_MFRMS frames between the same calls, with the Value range: 2~9). So, each time when a mobile phone tries to decode messages on a call sub-channel, DSC is increased by with each successful decoding of a message, but it should not exceed the initially set value; if message decoding fails, DSC will be decreased by 4. If DSC