ZTE RADIO PARAMETER DETAILS

7/30/2019 ZTE RADIO PARAMETER DETAILS

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ZTE University univ.zte.com.cnuniv.zte.com.cnuniv.zte.com.cnThe information contained in the file is solely property of ZTE corporation. Any kind of disclosing without permission is prohibited.

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The information contained in the file is solely property of ZTE corporation. Any kind of disclosing without permission is prohibited.ZTE University univ.zte.com.cnuniv.zte.com.cnuniv.zte.com.cn

ZXG10

Radio Parameters


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Contents

Network Identification Parameters CGI, BSIC )

System Control Parameters RLT, CBA, CBQ,etc )

Cell Selection Parameters ( C1, C2 )

Network Functional Parameters (INTAVE, LIMITn,etc )


4/63The information contained in the file is solely property of ZTE corporation. Any kind of disclosing without permission is prohibited.ZTE University univ.zte.com.cnuniv.zte.com.cnuniv.zte.com.cn

Network Identification Parameters

As a global cellular mobile communication system, theGSM strictly numbers each GSM network in each country,or even numbers each location area, every station or

every cell in every network in order that every cell aroundthe globe has an sole corresponding number.

This numbering mode aims to: Enable the MS to correctly identify the ID of the current

network so that it can correctly select the network theuser (or telecom operator) wants to access to in any

conditions. Enable the MS to correctly identify the ID ofthe current network so that it can correctly select thenetwork the user (or telecom operator) wants to access toin any conditions.



Roles of Network Identification Parameters

Enable the network to be real time informed of thecorrect geographical location of the MS so that the

network can normally connect various servicerequests with the MS as the terminal.

Enable the MS to report correctly the adjacent cellinformation during the conversation process so thatthe network can hand-over the calls when necessary

to ensure the continuity of the conversation.



Cell Global Identity CGI

CILACMNC

LAI

CGI

MCC



Setting of CGI

MCC resource is allocated and managed by ITU. TheMCC of China is 460decimal).

MNC is usually allocated by the relevanttelecommunication administration department of acountry.

The LAC encoding mode is specified correspondinglyby every country. Usually, the location area should beas large as possible.

Two or more cells in the same location area are notallowed to share the same CI.



BSIC

In GSM system, each BS is allocated with a localcolor code called base station identity code (BSIC). If,

in a physical location, one MS can receive the BCCHTRX of two cells at the same time and their channelnumbers are the same, the MS will distinguish themby the BSIC.



BSIC

BCC

BSIC

NCC

BSIC is composed of NCC(network color code) andBCC(base station color code).

NCC ranges from 07. BCC ranges from 07.



NCC and BCC

In the connection mode (during conversation), the MS mustmeasure the signals in the adjacent cells and report the

result to the network. As each measurement report sent bythe MS can only contain the contents of six cells, so it isnecessary to control the MS so as to only report theinformation of cells factually related to the cell concerned.The high 3 bits (i.e. NCC) in the BSIC serve this purpose.

The BCC is used to identify different BS using the same

BCCH in the same GSM PLMN.



BSIC Configuration Principle

CBA

FED

In general, it is required that Cells A, B, C, D, E and F use

different BSIC. When the BSIC resources are not enough,the cells close to each other may take the priority to usedifferent BSIC.



Roles of BSIC

1. When MS receives the SCH, it is considered to havesynchronized with the cell. But in order to correctly translatethe information on the downlink common signaling channel,

the MS must be aware of the training sequence code (TSC)used by the common signaling channel. The TSC used bythe common signaling channel of each cell is determined bythe BCC. So one of the functions of the BSIC is to inform theMS the TSC used by the common signaling channel of thecell.

2. As the BSIC takes part in the decoding process of therandom access channel (RACH), it can be used to preventthe BS from mis-decoding the RACH, sent by the MS to anadjacent cell, as the access channel of this cell.


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3. When the MS is in the connection mode (during conversation), itmust measure the BCCH level of adjacent cells specified in adjacent

cell tables broadcasting by BCCH and report the results to the BS. Inthe uplink measurement report, MS must show BSIC of this carrier ithas measured to every frequency point. In some special cases, i.e.two or more adjacent cells in a cell use the same BCCH, the BS can

distinguish such cells by way of BSIC in order to avoid the wronghandover or even the handover failure.


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BA

When a MS is turned on, it will scan from the BA(Adjacent cell BCCH table) it remembered when turnedoff last time. The MS will first search carriers from this

table and if none is found it will turns to find any of 30carriers with highest levels, then try to decode BCCHcarriers one by one according to their level sequences.


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Cell Selection

When the MS is turned on, it will try to contact a publicGSM PLMN, so the MS will select a proper cell and

extract from the cell the control channel parameters andprerequisite system messages. This selection process iscalled cell selection. The quality of radio channels is an

important factor in cell selection.

The GSM Specifications defines the path loss ruleC1.For the so-called proper cell, C1>0 must be ensured.


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C1

C1 = RXLEV - RXLEV_ACCESS_MIN- Max(MS_TXPWR_MAX_CCH - P ,0)

where,RXLEV_ACCESS_MIN is the minimum received level theMS is allowed to access the network

MS_TXPWR_MAX_CCH is the maximum power level ofthe control channel (when MS sending on RACH);RXLEV is average received level;

P is the maximum TX power of MS;MAXX, YX; if X Y.

MAXX, YY; if Y X.


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Path loss Criterion

All the candidate cells for MS must meet the pathloss criterion, i.e C1>0. MS will select the cell with the

maximal C1 to access and will camp on this cellunless some key conditions has changed greatly.


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RXLEV_ACCESS_MIN

In order to avoid providing unsatisfactory communication

quality and avoid the unnecessary waste of radio

resources if the MS accesses to the system (thecommunication quality after the access often cannotensure the normal communication process) at the verylow received level, the GSM system regulates that, whena MS is to access to a network, its receiving signal levelmust be larger than a threshold level, i.e. the minimumreceiving level the MS is allowed to access to

RXLEV_ACCESS_MIN).

Default value is 0 (-110dBm).


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Cell Reselection

The necessity to make a cell reselection

Parameters regarding to cell reselection

PI

C2

Cell Selection Hysteresis

CRO TO and PT

CBA

CBQ


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Definition

Cell reselection is a process MS change its service cell in

idle mode. When the MS selects a cell and if there are not

major changes in the various conditions, the MS will stayin the selected cell, and the MS will begin to measure thesignal levels of the BCCH TRX of its adjacent cells, record6 adjacent cells whose signal levels are the strongest andextract from them various types of system messages andcontrol messages of each adjacent cell. When givenconditions are met, the MS will move from the current cell

into another one. This process is called cell reselection.


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C2

When PI indicates YES the MS will get parameters

(CRO, TO and PT) , from BCCH, to be used to

calculate C2(channel quality criterion), which servesas cell reselection norm. The equation is as follows:

C2 C1 CRO H PT T TO, when PT 31C2 C1 CRO , when PT 31

Where T is a timer. When a cell is recorded by MS as one of the

six strongest cells,timer starts counting, otherwise, T is reset tozero.


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PI

PI is used to notify the MS whether to use C2 as thecell reselect parameter and whether the parameters

calculating C2 exist.

PI consists of 1 bit. 1means the MS should extract

parameters from the system message broadcastingin the cell to calculate the C2 value, and use the C2value as the standard for cell reselect; 0 means the

MS should use parameter C1 as the standard for cellreselect (equivalent to C2C1.


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C2

If the MS calculates that the C2 value of an adjacentcell (in the same location area with the current cell)surpasses the C2 value of the cell where the MSstays and maintains for 5s or longer, the MS will startcell reselection and access to the adjacent cell. If theMS detects a cell that is not in the same location area

with the current cell, the calculated C2 valuesurpasses the sum of the C2 value of the current celland the cell selection hysteresis (CSH) parameter

and if it remains for 5s or longer, the MS will startthe cell reselection and access to the new cell. Notethat the cell reselection caused by the parameter C2

should be originated at least at the interval of 15s soas to avoid the frequent cell reselection by MS.


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CELL SELECTION HYSTERESIS

When a MS reselects a cell, if the old cell and the

target cell are in different locations, then the MS mustinitiate a location updating process after cellreselection. Due to the fading features of the radiochannel, the C2 values of two adjacent cells measuredalong their borders will fluctuate greatly. As a result,

the MS will frequently conduct the cell reselection,which will not only increase the network signaling flowand lead to low efficiency use of radio resources, but

reduces the access success rate of the system, as theMS cannot respond to paging calls in the locationupdating process.


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CELL SELECTION HYSTERESIS

To minimize the influence of this issue, the GSMspecifications put forward a parameter called cellselection hysteresis (CSH), which requires that the

signal level of adjacent cell (in a different location area)be larger than the local cell signal level, and theirdifference be larger than the value specified by the

cell selection hysteresis. In this case, the MS will startthe cell reselection.

The cell selection hysteresis is represented in decimalnumerals, its unit is dB, its range is 014, its steplength is 2dB, and its default value is 4.


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CRO,TO and PT

The cell reselection initiated by the radio channelquality regards C2 as the standard. C2 is aparameter based on C1 plus some artificial offset

parameters. The artificial influence is to encouragethe MS to take the priority in accessing to some cellsor prevent it from accessing to others. These

methods are often used to balance the traffic in thenetwork.

In addition to C1, there are three other factorsinfluencing C2, namely: CELL_RESELECT_OFFSET(CRO), TEMPORARY_OFFSET (TO) andPENALTY_TIME (PT).


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CRO,TO and PT

The adjustments of above 3 parameters are as

followed:

1. In general, its not expected that MS access thecells where the traffic is very heavy or thechannel quality is very low. In this case , the PT

may be set 31, making TO invalid, so C2=C1-CRO.Because the C2 is lowered deliberately, thepossibility that the cell will be reselected by MS is

lowered greatly. The greater the CRO, the lesspossibility that the cell will be reselected, andvice versa.


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CRO,TO and PT

2. On the other hand, its expected that MS stay

as much as possible in cells where the systemutilization are very low and the traffic load is light.

In this case, its recommended that CRO beranged from 0 to 20dB. The greater the CRO, themore possible the cells will be reselected ,and

vice versa. Its also suggested that TO is equal ora litter higher than CRO. PT, whose main role is toavoid frequent cell reselection by MS, is generallyrecommended to be set at 20 seconds or 40seconds.


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3. For cells where the traffic is moderate, therecommended value for CRO is zero and PT 620

seconds, thus causing C2=C1, i. e. no artificialimpact will be imposed.


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CBA

In the system message broadcasting in each cell, there isa bit information indicating whether to allow the MS toaccess to it, which is called cell bar access (CBA). The

parameter CBA is to indicate whether the cell bar accessis set in a cell.

The parameter is represented in character string. Its value

range is:

YES: Set the CBA; NO: Do not set the CBA.

The CBA bit is a parameter for the network operator toset. Usually all the cells are allowed to be accessed byMS , so the bit is set NO. However, in special cases, thetelecom operator may want to assign a certain cells forhandover service only, then the bit can be set YES.


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Application of CBA

Area A

BTS A

BTS B

BTS C


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Application of CBA

Suppose Area A (shaded part) in the figure is thebusy area (e.g. commercial area in a large city), weusually adopt the micro cellular mode to increase the

access rate of the area via the limited frequencyresources. We often use the double layer networkconcept, i.e. to set up BTS A (its capacity can be

smaller) to cover the whole Area A, in order to reducethe handoff times while the MS is moving rapidly.


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Application of CBA

In general situations, the MS works in the microcellular (you can set the priority of the cell and properreselect parameter to achieve this purpose). When

the MS is moving at a fast speed during aconversation, the network will force the MS to behanded over to BTS A.


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Application of CBA

If the MS is just near BTS A and at the edge of a microcellular after the conversation, the MS will not start thecell reselect process according to the GSM

specifications because the signal quality of BTS A is farbetter than that of the micro cellular BTS . As a result,the MS cannot return to the micro cellular cell. As the

capacity of BTS A is usually smaller, the abovesituation will lead to the congestion of BTS A. To solvethis problem, you can set the CBA of BTS A as 1, thatis to forbid the MS from directly accessing to BTS A,and permit only the handover service to access to thecoverage of BTS A.


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CBQ

In areas where the cells overlay with each other and differ in

capacity, traffic and functions, the telecom operator oftenhopes that the MS can have priority in selecting some cells,

that is, the setting of cell priority. This function is set by way ofthe parameter "Cell Bar Qualify" (CBQ).

CBQ CBA Cell selection priority Cell reselection stateNO NO Normal Normal

NO YES Barred Barred

YES NO Low NormalYES YES Low Normal


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Example of CBQ Setting

For some reasons, the traffic of Cells A and B is apparently higher

than that of other adjacent cells. To balance the traffic in the wholearea, you can set the priority of Cells A and B as low, and set thepriority of the rest cells as normal so that the traffic in the shade areawill be absorbed by adjacent cells. It must be noted that the result ofthis setting is that the actual coverage of Cell A and Cell B is narrowed.However, this is dissimilar to reducing the transmitting power of Cell Aand Cell B, the latter may cause blind areas of the network coverageand the reduction of communication quality.


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Random Access

Random access is the process that messages beingtransmitted on RACH when a MS turns from idle tospecialized mode.

The main parameters includes:

MAX RETRANS

AC

RE


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MAX RETRANS

When starting the immediate assignment process(e.g, when MS needs location updating, originatingcalls or responding to paging calls), the MS will

transmit the "channel request" message over theRACH to the network. As the RACH is an ALOHAchannel, in order to enhance the MS access success

rate, the network allows the MS to transmit multiplechannel request messages before receiving theimmediate assignment message. The numbers of

maximum retransmission (MAX RETRANS) aredetermined by the network.


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MAX RETRANS

The MAX RETRANS is often set in the following ways:

For areas (suburbs or rural areas) where the cell radius is

more than 3km and the traffic is smaller, the MAXRETRANS can be set 11(i.e. the MAX RETRANS is 7).

For areas (not bustling city blocks) where the cell radius is

less than 3km and the traffic is moderate, the MAXRETRANS can be set 10i.e. the MAX RETRANS is 4.

For micro-cellular, its recommend that the MAXRETRANS be set 01i.e. the MAX RETRANS is 2.

For microcellular areas with very high traffic and cells withapparent congestion, its recommend that the MAXRETRANS be set 00i.e. the MAX RETRANS is 1).

A C l (AC)


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Access Control (AC)

In some special conditions, the telecom operator wants to bar all

or part of MS from sending out the access request or pagingresponse request in some special areas. For example, in case

some areas are in emergency state or in case a GSM PLMNencounters a serious fault. For this reason, GSM Specification 02.11 stipulates that each GSM subscriber (ordinary

subscriber) is allocated with an access level. The access levelranges from 0 to 9 and is stored in the SIM card of the subscriber.The GSM Specifications reserves 5 special access levels forsome special subscribers, which range from 11 to 15. These

levels usually have higher access priority. Special subscribers canhave one or more access levels (11~15), and their access levelsare also stored in the SIM cards.


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AC

The access levels are distributed as follows:

C 0C9: ordinary subscribers;

C11: used for PLMN management; C12: used by the security department;

C13: public utilities e.g. water, gas;

C14: emergency service;

C15: PLMN staff.

S i f AC


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Setting of AC

In the BS installation and commissioning process orin the process of maintaining or testing some cells,the operator can set C0C9 as 0 to forcedly forbid

the access of ordinary subscribers so as to reducethe unnecessary effects on the installation ormaintenance work.

In some cells with very high traffic, the congestion willoccur in busy hours. For example, the RACH conflicthappens frequently, the AGCH is overloaded and the

Abis interface flow is overloaded. The networkoperator can set proper access control parametersC0C15to control the traffic of some cells.

Reestablishment Enable


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Reestablishment Enable

For the drop calls caused by the radio link fault due to the burstinterference or blind areas owing to the high rise buildings, the MScan start the call reestablishment process to resume theconversation, but the network is entitled to determine whether the

call reestablishment is allowed or not. 0=Yes, 1=No.

In some special circumstances, the drop call may occur when theMS goes through a blind area during the conversation. If the callreestablishment is allowed, the mean drop call rate will be reduced.However, the call reestablishment process will occupy a longerperiod of time, most of the subscribers have hung up before thereestablishment process is over, as a result, the call reestablishmentfailed to achieve its purpose and wasted many radio resources. Werecommend that the call reestablishment be not allowed in thenetwork except for some individual cells.

LIMIT


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LIMITn

According to GSM Specification 05.08, the BTS mustmeasure the interference levels of the upward links of allthe free channels for the purpose of providing basis formanaging and allocating radio resources. Moreover, theBTS should analyze its measured results, divide theinterference levels into 5 grades and report them to the

BSC. The division of the 5 interference grades (i.e. the so-called interference bands) is set by the operator through theman-machine interface. The parameter "Interference band

border(LIMITn) determines the borders of the 5interference bands.

S tti f LIMIT


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Setting of LIMITn

0


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IMSI Attach/Detach(ATT)

The IMSI detach process is that: the MS notifies the network that it

is moving from the working state to the non-working state, or the

process of the SIM card being taken from the MS. When receiving

the notification from the MS, the network will indicate the IMSIsubscriber to be in the non-working state, so the connectionrequest ending the subscriber as the called party will be rejected.

The corresponding IMSI attach process is that the MS notifies the

network that it has been in the working state , or the SIM card is re-inserted into the MS. When the MS re-enters the working state, itwill detect whether the current LAI is the same as the LAI finally

recorded in the MS. If they are the same, the MS will start the IMSIattach process, otherwise the MS will start the location updating

process (instead of the IMSI attach process). When receiving thelocation updating or IMSI attach process, the network will indicate

the IMSI subscriber being in the working state.

IMSI Attach/Detach (ATT)


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IMSI Attach/Detach (ATT)

An ATT mark should be set as YES so that the network will no longerprocess the connection process using the MS as the called after theMS shuts down, thus saving the processing time of the networkentities and saving lots of network resources.

Please note that the ATT in different cells but in the same locationarea should be set the same. Because the shutdown of the MS incells where the ATT is YES will start the IMSI detach process, and the

network will record the fact that the MS is in the non-working state andreject all the connection requests when using MS as the called. Whenthe MS restarts and is in the same location area (so the locationupdate process is not started) as when it shuts down but is in a

different cell and the ATT of the cells is set as NO, so the MS will notstart the IMSI attach process, either. In this case, the MS cannotbecome the called party until it starts the location updating process.

CCCH_CONF


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The CCCH can be one or more physical channels. TheCCCH and SDCCH can share the same physical channel.The combination mode of the common control channel in a

cell is determined by the CCCH_CONF.

CCCH_CONF Coding Meanings CCCH message blocks in oneBCCH

000CCCH use one basic physical channel, not shared with SDCCH 9

001CCCH use one basic physical channel, shares with SDCCH 3

010CCCH use two basic physical channels, not shared with SDCCH 18

100CCCH use three basic physical channels, not shared with SDCCH 27

110CCCH use 4 basic physical channels, not shared with SDCCH 36

Others Reserved

Setting and Impact of CCCH CONF


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Setting and Impact of CCCH_CONF

The CCCH_CONF is determined by the telecomoperation department according to the traffic model of acell. It is often decided in the system design period.

According to the ordinary experience, if a cell has 1 or 2TRX, we recommend that the CCCH uses one basicphysical channel and shares it with the SDCCH; if a cell

has 3 or 4 TRX, we recommend that the CCCH uses onebasic physical channel but does not share it with theSDCCH.

AGBLK


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AGBLK

Since the CCCH consists of the access grant channel(AGCH) and paging channel (PCH), it is necessary toset how many blocks of the CCCH information blocks

are reserved and dedicated to the AGCH. To let the MSknow about the configuration information, the systemmessage of every cell contains a configuration

parameter, that is, the access grant reserve blocks(AGBLK).

AGBLK is represented in decimal numerals, and its

value range is: CCCH is not combined with SDCCH: 07.

CCCH is combined with SDCCH: 02.

Setting and Impact of AGBLK


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g p

The AGBLK setting principle is: given that the AGCH isnot overloaded, try to reduce the parameter as much aspossible to shorten the time when the MS responds to the

paging and improve the quality of service of the system.

The recommended value of AGBLK is usually 1 (when the

CCCH is combined with the SDCCH), 2 or 3 (when theCCCH is not combined with the SDCCH).

BS-PA-MFRMS


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According to the GSM specifications, every mobile subscriberbelongs to a paging group. In every cell, every paging groupcorresponds to a paging subchannel, the MS calculates thepaging group to which it belongs by basing on its own IMSI, thencalculates the location of the paging subchannel belonging tothe paging group. In an actual network, the MS only"receives the contents in the paging subchannel to which it

belongs but ignores the contents in other paging subchannels,or even turn off the power supply of some hardware equipmentof the MS for other paging subchannels to save the MS poweroverhead (i.e. DRX source). The BS-PA-MFRMS refers to how

many multi-frames are used as a cycle of a paging subchannel.This parameter in fact determines how many paging sub-channels are to be divided from the paging channels of a cell.

BS-PA-MFRMSis represented in decimal numerals and its


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value range is 2 9, its unit is multiframe

51 frames , its default value is 2BS-PA-MFRMS Multiframes of the same paging

group that cycle on the pagingchannel

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

Periodic Updating Timer (T3212


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The reasons for the location update in the GSM system are

of two types: one is that the MS finds its location area

changed (with a different LAC), the other one is that thenetwork requires the MS to periodically update its location.The frequency of periodic location update is controlled viathe network and the period length is determined by the

parameter T3212.

In general, in areas with larger traffic and signaling flow,you should select the larger T3212e.g. 16 hours, 20

hours or even 25 hours, but in areas with smaller trafficand lower signaling flow, you can set the smallerT3212 (3hours or 6 hours, etc.). In areas where traffic is far beyondthe system capacity, we recommend that you set T3212 as

0.

NCCPERM


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NCCPERM

In the connection mode (during the conversation), the

MS will report the measured signals of the adjacentcells to the BS, but each report may contain at most 6

adjacent cells, Therefore, let the MS only report theinformation of the cells that may become the hand-overtarget cells, do not let the MS report the information

merely according to the signal level without selection(usually do not let the MS report other GSMPLMN cells).The above functions can be fulfilled by limiting the MSto merely measure the cells whose NCC have beenspecified. The NCCPERM lists the NCCs of cells to bemeasured by the MS.

NCCPERM


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In general, each area is allocated with one (or several)NCC. The NCCPERM of each cell in the area shouldcontain the NCC of the area, otherwise a large

number of cross-cell drop calls will occur and the cellreselection will fail. To ensure the normal roamingbetween different areas, the border cells of an area

should contain the NCC of its adjacent areas.


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MBCR


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In the single band GSM system, when the MS reports

the adjacent cell measurement result to the network, itonly needs to report the contents of the 6 adjacent cells

with the strongest signals in a band. When multiplebands form a network, the telecom operator often,according to the actual situation of the network, wants

the MS to access to a frequency band with priorityduring the handover, so the operator hopes that the MSwill report the measurement result on the basis of notonly signal strength but signal band as well. Theparameter "multiband indication (MBCR)" is used tonotify the MS that it should report the multibandadjacent cell contents.

The value is 0-3

MBCR


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0: Based on the signal strength of adjacent cells, theMS reports the measurement results of 6 adjacentcells whose signals are the strongest, whose NCC

are known and allowed no matter in which band theadjacent cells lie.

The default value is 0

MBCR


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1: The MS should report the measurement result of anadjacent cell in each band (not including the band usedby the current service area) in the adjacent table, whose

signal is the strongest and whose NCC is alreadyknown and allowed. It should also report in the restposition the adjacent cells in the band used by thecurrent service area. If there are still rest positions, it will

report the information of the rest adjacent cells nomatter in which band these adjacent cells lie.

MBCR


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2: The MS should report the measurement results oftwo adjacent cells in each band (not including the bandused by the current service area) in the adjacent table,

whose signals are the strongest and whose NCC arealready known and allowed. It should also report in therest position the adjacent cells in the band used by thecurrent service area. If there are still rest positions, itwill report the information of the rest adjacent cells nomatter in which band these adjacent cells lie.

MBCR


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3: The MS should report the measurement results ofthree adjacent cells in each band (not including theband used by the current service area) in the adjacenttable, whose signals are the strongest and whoseNCC are already known and allowed.


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ZTE RADIO PARAMETER DETAILS