microsoft power point - 11 omf000406 advanced radio resource management issue1

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

Advanced Radio

Resource 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.


� Each successful seizure� -1

� Once interference occur in each seizure� +1

� Each failed seizure� +2

� Each call drop� +2


Channel Assignment 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 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.



� 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



� 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



� 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 channel

available?

More than one halfrate channel?

Request reject

Assign full rate channel

Convert couple channel to full

rate channel and then assign

the converted channel

Initiate intracell handover to

form 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 avai lable?

Couple channel available?

Full rate channel available?

Assignment fai ls

Assign half ratechanel

Assign the half rate

channel on the

couple channel

Convert the ful l rate

channe into couple

channel and then assign

the half rate channel on

the couple channel

Start

End



� 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 into 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

establishment 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.



� 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 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.



� If the conditions mentioned above are met, select the full rate TCH

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.



� 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.



� 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 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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microsoft power point - 11 omf000406 advanced radio resource management issue1

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