5....omf000406 advanced radio resource management issue1.1

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

Advanced RadioResource Management


Foreword

To satisfy different environments, many kinds of

advance radio resource management algorithms are

adopted, including Huawei II CH allocation algorithm,

H/F rate CH conversion 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

assignment algorithm. Master the parameters of H/F rate CH conversion. Understand TCH/SDCCH conversion.


Contents

1. HW II CH Ass. Algorithm

2. H/F CH Conversion

3. TCH/SDCCH Conversion


Channel Assignment Algorithm

HW I Channel Assignment Algorithm

Uses the sequent selection mode to allocate channels.

The advantage is terse and high efficiency.

It is not able to allocate CH according to TRX priority,

interference, etc.

HW II Channel Assignment Algorithm

Allocates channels by optimum.

Always choose the best one.

Lower efficiency.


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

selection. The optimum factors are as follows:

Channel priority of IUO cell TRX property

Channel type priority

Interference priority

TRX priority

History record priority

The overall priority is based on these five sub-priorities. The

available channel with highest overall priority is assigned.


Channel Assignment Priority Channel priority of IUO cell TRX property

If the IUO TRX property meets the condition of optimum

selection, the Channel priority of IUO cell TRX property is 0.

Otherwise, it is 1.

Channel type priority

For the SDCCH, the channel type priority is 0, which means

this priority is not considered. For the TCH, the priority of

dynamic PDCH is 1 and that of other channels is 0.

Interference priority

The channel with less interference is assigned first.


Channel Assignment Priority TRX priority

The channel is assigned on this basis of whether the TRXs is BCCH TRXs, the multiplexing distance of the TRX frequency, whether this TRX join in frequency hopping, and the number of hopping frequencies. This priority can reduces network interference and improve the network quality.

History record priority Each successful seizure -1 Once interference occur in each seizure +1 Each failed seizure +2 Each call drop +2


Channel Assignment Priority

History record priority

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.


Parameter Introduction SD Allocation Priority Allowed

Range: Yes, No Default: Yes Description: If the setting is "No", then the roll selection i

s 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 pr

iority is allowed.


Parameter Introduction

Active Ch Interf. Meas. Allowed Range: Yes, No Default: Yes Description: Indicates whether the interference of the active channel is mea

sured. 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 “I

nterf. 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 not 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





H/F CH Conversion Channel definition

Single:

Couple:

Rate adjustment Definition: The conversion from full rate to half rate or from half rate to

full rate is called rate adjustment.

Principle: Before assign the channel, determine whether to adjust the rate or not according to the channel resources in the cell. If yes, assign the channel to the current call after adjusting the rate. That is, adjust the rate in real time.

Idle Busy

Idle Idle


Channel Allocation Strategies MSC channel assignment strategy

Assign the channel according to the MSC request. If the

request from MSC is "TCH/F preferred", assign the full rate

channel preferentially. If it is "TCH/H preferred", assign the

half rate channel preferentially.

BSC channel assignment strategy

When the assignment request sent from MSC is "Full rate TCH

preferred" or" Half rate TCH preferred", BSC assigns the

proper channel according to the availability of idle full rate

channel in the cell and the allowance of MSC.


H/F CH Conversion Full rate only

Yes

Yes

Yes

No

No

No

Assignmentrequestfor TCHF only

Full rate available?

Couple channelavailable?

More than one halfrate channel?

Request reject

Assign full rate channel

Convert couple channel to fullrate channel and then assign

the converted channel

Initiate intracell handover toform couple channel, and thenconvert the couple channel to

full rate channel to assign

Start

End


H/F CH Conversion Full rate preferentially

Yes

Yes

No

No

No

Yes

Assign request for full rae preferentially

Full rate available?

Couple channel available?

More than one half ratechannel?

Assign full rate channel

Convert the couple channelinto full rate channel to

assign

Form couple channel byintracell handover and thenconvert couplechannel into

full rate to assign

Start

End

Assign request for full rae preferentially


H/F CH Conversion Half rate only

or preferentially

Yes

Yes

Yes

No

No

No

Half rate assignment request

Single channel available?

Couple channel available?

Full rate channel available?

Assignment fails

Assign half ratechanel

Assign the half ratechannel on thecouple channel

Convert the full ratechanne into couple

channel and then assignthe half rate channel on

the couple channel

Start

End


Parameter Introduction TCH Rate adjust Traffic Thrsh (%)

Range:0~100 Unit:% Default:80 Description: It is one of the terms for the full rate TCH to convert int

o the half-rate TCH. Only if the traffic (number of currently active channels / number of available channels in a cell) is greater than the threshold, and “TCH Rate Conversion" is set as “Yes", can the full rate TCH convert into the half rate TCH to expand system capacity.



Enhanced Chan. Convert Enable Range: Yes, No Default: Yes Description: When need toadjust the half rate to full rate, hand over the call

on the single channel out and then adjust the rate.

Chan. Conversion Timer (100ms) Range:20~255 Default:30 Description: It is the timer waiting for the channel conversion during the est

ablishment of a call. If the channel is not converted within the set time, the call is cleared and the number of timeout is counted.


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 adjust

ment can be started under the following conditions: The time should not be during the resource check. The BSC internal flow control level should be equal to 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 also <= 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.



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 active 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 T

CH as follows: None IUO cell

Idle TCH/F Active TCH/F

None 900/1800 hybrid IUO cell Idle TCH/F in underlaid cell Active TCH/F in underlaid cell Idle TCH/

F in overlaid cell Active TCH/F in overlaid cell

900/1800 hybrid IUO cell Idle TCH/F in underlaid cell Active 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 active 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 Introduction 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 Introduction 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 switc

hed back to TCH.


Summary

In this course, we have learned the parameter of HW II CH Ass. Algorithm, H/F rate CH conversion, TCH/SDCCH conversion.

Apllication should be depended on the real

environment.

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5....omf000406 advanced radio resource management issue1.1

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