OMF000410 BSC6000 Radio Channel Management ISSUE1.0

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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.

BSC6000Radio Channel Management


Foreword

To satisfy different environments, many kinds of

advance radio resource management algorithms are

adopted, including Huawei II CH allocation algorithm

and TCH/SDCCH conversion. They are designed to

improve the performance of network.


Objectives

Upon completion of this course, you will be able to:

Master the main idea and parameters of HWII CH Ass.

Algorithm.

Understand TCH/SDCCH conversion.


Contents

HW II Channel Assignment Algorithm

TCH/SDCCH conversion


Contents


TCH/SDCCH Conversion


HW II Channel Assignment Algorithm When the radio resource such as SDCCH and TCH is

required, channel assignment process starts.

HW II channel assignment algorithm is based on

optimum selection. The available channel with

highest overall priority is assigned.


HW II Channel Assignment Algorithm Processing of

channel assignment

Huawei II Channel Assignment Algorithm


HW II Channel Assignment Algorithm HW II channel assignment algorithm is based on optimum

selection. The optimum factors are as follows:

1. Different band priority 7. Channel type priority

2. Different TRX priority 8. AMR priority

3. IUO cell TRX property 9. History record priority

4. TRX capability of frequency band 10. Interference priority

5. Channel rate adjustment priority 11. TRX priority

6. Channel rate priority


HW II Channel Assignment Algorithm Different band priority

This sub-priority is only available for TCH re-assignment.

This priority corresponds to the relationship between the value

of Frequency band of reassign and the frequency band of

current channel and the assigned channel for last time.

Different TRX priority

This sub-priority is only available for TCH re-assignment.

If the TRX of current channel is the same as that of the

assigned channel for the last time, the priority level of

different TRX of the channel is 1; Otherwise, it is 0.


HW II Channel Assignment Algorithm IUO cell TRX property

The criteria are the same for TCH and SDCCH. This sub-

priority will be 1 just when all of the following

conditions are fulfilled; Otherwise, it is 0.

Current cell is a concentric cell.

The property of current channel is different with the

demanded property which is described in channel

required.


HW II Channel Assignment Algorithm TRX capability of frequency band

This sub-priority totally has 8 bits. They indicate

DCS1800, PCS1900, GSM480, GSM450, GSM850, R–

GSM, E–GSM and P–GSM.

Corresponding bit is 1, when BCCH frequency band of

current cell and this MS both can support this

frequency band. Otherwise, it is 0.


HW II Channel Assignment Algorithm Channel rate adjustment priority

This sub-priority is only available for TCH.

This sub-priority depends on the TCH Rate Adjust Allow. If

this parameter is set to YES, this sub-priority is 1; Otherwise, it

is 0.

Channel rate priority

For SDCCH channel, this sub-priority is 0.

If the speech version is AMR, this sub-priority is 0.

Channel rate priority has 2 bits. High bit indicates that whether the channel type is the same as the required one.

Low bit indicates the rate priority.


HW II Channel Assignment Algorithm Channel type priority

For SDCCH channel, the channel type priority is 0.

For TCH channel, the priority of dynamic PDCH is 1 and

that of other channels is 0.

AMR priority

This one is reserved.


HW II Channel Assignment Algorithm History record priority

Each successful seizure -1

Once interference occur in each seizure +1

Each failed seizure +2

Each call drop +2

Times refresh

– Timed refresh is used to restore the worsened history record

priority. The history record priority is reduced by a constant at

regular intervals. You can set the interval and the constant.

Usually, a short interval and a small constant are preferred.


HW II Channel Assignment Algorithm Interference priority

Interference priority depends on the interference band

value.

The channel with less interference is easily assigned

first.

TRX priority

TRX priority depends on the TRX priority level. The

channel with high priority level has low priority and is

difficult to be assigned.


Parameter Introduction

SD Allocation Priority Allowed Range: Yes, No

Default: Yes

Description: If the setting is "No", then the roll selection is adopted

for SDCCH allocation. If the setting is "Yes", then the optimum

selection is adopted.

Interf. Priority Allowed Range: Yes, No

Default: Yes

Description: Indicates whether the interference record priority is

allowed.



Active Ch Interf. Meas. Allowed Range: Yes, No

Default: Yes

Description: Indicates whether the interference of the active channel

is measured. If the setting is "No", the system does not judge

whether the active channel is interfered, nor sending interference

indication message. Otherwise, judgment will be made.

Allocation TRX priority allowed Range: Yes, No

Default: Yes

Description: Whether the TRX priority is used for allocation.


Parameter Introduction History records priority allowed

Range: Yes, No

Default: Yes

Description: Whether the history record priority is used for

allocation.

Balance traffic allowed

Range: Yes, No

Default: Yes

Description: If the setting is "No", the channel next to the

previously allocated channel will be the starting channel for

searching a qualified channel to be allocated.


Parameter Introduction Interf. of UL Level thrsh.

Range:0~63,(-110dBm~-47dBm)grade

Default:31

Description: Threshold of uplink strength interference. If the uplink strength of a

channel is greater than this threshold and the uplink signal quality is worse than

or equal to the “Interf. of UL Qual. Thrsh.”, then uplink interference exists.

Interf. of UL qual. Thrsh.

Range:0~70, (RQ0~RQ7)

Default:40

Description: Threshold of uplink quality interference. See the description of

“Interf. of UL level Thrsh. “.

Interf. of DL Level thrsh. and Interf. of DL qual. Thrsh.

Are the same as uplink


Parameter Introduction Filter length for TCH Level

Range:1~32

Default:6

Description: Used to filter the receiving signal strength of speech/data channel.

Filter length for TCH Qual. Range:1~32

Default:6

Description: Used to filter the receiving signal quality of speech/data channel.

Filter length for SDCCH Level and Filter length for SDCCH

Qual. Are the same as previous parameter


Parameter Introduction Update Period of CH Record

Range:1~1440

Unit: minute

Default: 30

Description: In HW_II channel management algorithm, every

time the duration (set by this parameter) expires, the history

record of every channel will be refreshed through subtracting

the value of “Update Freq. of CH record ". Thus the channel

priority is raised. This parameter together with the "Update

Freq. of CH record " works to prevent a channel from being

allocated again, which has been deteriorated for a period.



TRX priority Range: Level 0~Level 7

Default: Level 0

Description: The priority of TRX (valid in HW_II channel allocation

algorithm only).

Update Freq. Of CH record Range:0~63

Default:2

Description: The history record priority higher than the value of this

parameter will be refreshed through subtracting the value of this

parameter. See the description of “Update Period of CH record”


Contents




TCH/SDCCH Conversion SDCCH dynamic adjustment optimizes the usage of the

traffic channel and signaling channel, reduces the

SDCCH channel block and mitigates the impact on

system performance caused by SDCCH initial

configuration.

The adjustment process is triggered every time before

channel assigning, but the adjusted SDCCH can be only

used in the next occupying quest.

Only support the dynamic adjustment between TCH/F

and SDCCH.


TCH/SDCCH Conversion After the SDCCH dynamic adjustment process is triggered,

dynamic adjustment can be started under the following

conditions: The time should not be during the resource check.

The BSC internal flow control level should be less than 0.

Dynamic adjustment of other SDCCH in the cell should not be in progress.

“SD Dynamic Allocation Allowed” should be “Yes”.

The cell idle SDCCH number should be smaller than the “Idle SD Thrsh.”.

The number of the SDCCHs +8 should be less than “Cell SD Maximum”.

If the number of the cell idle TCH/F + (the number of the cell idle TCH/H)/2

4 ,and the number of the TRXs in the cell, the dynamic SDCCH adjustment is

not allowed. Otherwise, allowed.

There should be proper Full rate TCH for adjustment.


TCH/SDCCH Conversion The full rate TCH can be adjusted as the SDCCH only when it meets the

following conditions:

The band class of the frequency should be the sub set of or the

same as the band class of the BCCH frequency.

The initial data configuration of the channel should be full rate

TCH.

The number of SDCCHs on the TRX should be no more than eight.

The channel should be in the occupied state or idle state.

The full rate TCH channel in BCCH carrier of multi TRXs cell

should not be adjustment.


TCH/SDCCH Conversion If the conditions mentioned above are met, select the full

rate TCH as follows:

None IUO cell Free TCH/F Occupied TCH/F

None 900/1800 hybrid IUO cell Free TCH/F in underlaid cell Occupied TCH/F in underlaid cell

Free TCH/F in overlaid cell Occupied TCH/F in overlaid cell

900/1800 hybrid IUO cell Free TCH/F in underlaid cell Occupied TCH/F in underlaid cell

The inner channel can not be adjusted.



Yes No

NoYes

No

Yes

3 second timertimes out

Idle SDCCHnumber >N1+8?

Yes No

C-3 C+12

C<=0?

Whether there isSDCCH not swtiched

back?

Whether swtichingback is proper ?

Select an SDCCHto Switch back

Restart the 3second timer

Stop the 3second timer

Restart the 3second timer

Start

End



The system decides “whether there is a proper SDCCH

to switch back” according to the following conditions:

All the SDCCHs of the timeslot are occupied or idle.

When the conditions mentioned above are met, select

the SDCCH to adjust in the following two situations If it is not an IUO cell, select randomly an SDCCH adjusted from a

full rate TCH.

If it is an IUO cell, select first the SDCCH adjusted from a full rate

TCH on the UL subcell. If there is no, select the SDCCH adjusted

from a full rate TCH on the OL subcell.


Parameter Instruction SD Dynamic Allocation Allowed

Range: Yes, No

Default: Yes

Description: Indicates whether SDCCH dynamic allocation is

allowed.

Idle SD Thrsh.N1

Range:0~63

Default:2

Description: When the number of the idle SDCCH is smaller

than this parameter, the TCH can be adjusted to SDCCH.


Parameter Instruction Cell SD Maximum

Range:0~255

Default: Configured SDCCHs + 8

Description: The maximum number of SDCCHs in the cell.

TCH Min. Recovery Time

Range:60~3600

Unit: Second

Default: 600

Description: The minimum duration for the SDCCH to be

switched back to TCH.


Summary

In this course, we have learned

HW II channel assignment algorithm.

TCH/SDCCH conversion.

Application should be depended on the real

environment

Thank youwww.huawei.com

OMF000410 BSC6000 Radio Channel Management ISSUE1.0

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