microsoft power point - 9 omf000407 multiple rate algorithm issue2
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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Multiple Rate Algorithm
Page2Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Objectives
� Upon completion of this course, you will be able to:
� Understand the multiple rate algorithm function and types.
� Master the parameters of multiple rate algorithm.
� Be able to configure the data of multiple rate algorithm.
Page3Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Full Rate
� Traffic Channel (TCH) carries coded voice data. The full-
rate TCH is initially adopted to carry information at the
gross rate 22.8Kbit/s. The information contains the source
coding rate of 13Kbit/s.
� As technologies develop, the enhanced full rate, half rate,
multiple rate and other coding are introduced.
Page4Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Circuit Pool Function
� “Circuit pool number” actually represents the circuit type,
indicating the support capability of the voice codec.
� Different circuit pool numbers can support different voice rates.
Page5Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Circuit Pool Function
FR speech version 2;FR data (12, 6, 3.6 Kbps)
HR speech version 1;HR data (6, 3.6 Kbps) 6
FR speech version 1;FR speech version 2
FR data (12, 6, 3.6 Kbps) 5
FR speech version 2;FR data (12, 6, 3.6 Kbps) 4
FR speech version 1;FR data (12, 6, 3.6 Kbps);
HR speech version 1;HR data (6, 3.6 Kbps)3
HR speech version 1;HR data (6, 3.6 Kbps) 2
FR speech version 1;FR data (12, 6, 3.6 Kbps) 1
Supported RateCircuit Pool Number
Page6Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Circuit Pool Function
FR speech version 1;FR speech version 2
FR speech version 3;FR data (12, 6, 3.6 Kbps)
HR speech version 1;HR speech version 3
HR data (6, 3.6 Kbps)
27
FR speech version 1;FR speech version 2
FR speech version 3;FR data (12, 6, 3.6 Kbps)
HR speech version 3
25
FR speech version 3;FR data (12, 6, 3.6 Kbps)
HR speech version 3 24
FR speech version 3;HR speech version 323
FR speech version 1;FR speech version 2
FR data (12, 6, 3.6 Kbps);HR speech version 1
HR data (6, 3.6 Kbps)
7
Supported RateCircuit Pool Number
Page7Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. EFR
2. HR
3. AMR
Page8Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of EFR
� The Enhanced Full Rate (EFR) is a speech coding scheme with
an enhanced full rate. Using this coding scheme, you can provide
services with better speech quality.
� In the wireless communications system, the EFR applies to only
speech services and is irrelevant to data services or signaling
services.
� The EFR function adopts the CELP( Code Excited Linear
Predictive Coding) coding scheme, thus improves the quality of
the speech signal.
� When EFR is adopted, the transmission rate of the speech
signal of an MS on the air interface is 12.2 kbit/s.
Page9Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Call Set-up Flow
Determine whether the circuit
pool where a call ocuupies the
CIC supports EFR
Common call (FR)
EFR call
Speech version in the
assignment request is EFR
Start
Finish
Yes
No
Page10Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Call Signaling Processing
BSC
ASS REQ(1)
Channel ACT(2)
Channel ACT ACK(3)
ASS CMD(4)
SABM(5)
UA(6)
EST IND(7)
ASS CMP(8)
ASS CMP(9)
MS MSCBTS
Page11Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Data Configuration
� In BSC, to support EFR function, it is necessary to configure
the number of the circuit pool in A interface.
� If the half rate and AMR functions are not adopted, the
number of the circuit pool for the EFR function is
recommended to set to 5.
� You can dynamically modify the number of the circuit pool
that the circuits reside on the FTC board. choose BSC �
Dynamic Configuration without Command �Trunk Circuit.
The dialog box is displayed as shown in following slides.
Page12Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Data Configuration
Page13Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Data Configuration
� Click Trunk Circuit.
� The select FTC dialog box is displayed as shown in the following.
Page14Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
EFR Data Configuration
Page15Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. EFR
2. HR
3. AMR
Page16Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of HR
� The half rate voice coding uses a new voice coding
algorithm to reduce the voice coding rate to half that of full
rate voice service. Thus, one physical channel that can
only support one call under the full rate can support two
calls under half rate.
� If the half rate service is used, the voice capacity expands
twice without adding TRXs. By adopting half rate service,
the operator can fully use the current network to expand
the system capacity. This saves the cost and eases the
spectrum use.
Page17Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of HR
T T T T T T T T T T T S T T T T T T T T T T T T IT
T T T T T T S T T T T T T
T T T T T T T T T T T T S
Page18Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of HR
� Single:When a timeslot is used as two TCH/H channels, one
TCH/H channel is busy and another is idle. The idle
TCH/H channel is called single channel or channel
fragment or fragment.
Idle Busy
Page19Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of HR
� Couple:When a timeslot is used as two TCH/H
channels, and these two channels are both free. This
timeslot is called a couple.
Idle Idle
Busy Busy
Page20Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of HR
I: Idle B::::Busy
I B B B B B B BBIB BB B BB
I I B B B B B BBBB BB B BB
Page21Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Channel Assignment Strategies
� If the half rate function is used, when BSC receives the
“assignment request” from the MSC, it will decides to use the
channel allocation algorithm according to channel assignment
strategy specified in the data configuration.
� MSC channel assignment strategy
� Assign the channel according to the MSC request. If the request from MSC
is "TCHF preferred", assign the full rate channel preferentially. If it is
"TCHH 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.
Page22Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Channel Assignment Strategies
� The BSC channel allocation strategy is the default strategy.
That is, when the network is idle, the full rate is used,
otherwise, the half rate is used.
� For the call that uses the half rate preferentially, the single
channel is assigned preferentially to reduce the fragment.
� If a cell has multiple TRXs, the channels on the TRXs that do
not allow the rate adjustment are assigned preferentially.
Page23Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
� If the channel assignment request is to choose the full rate channel only:
� When there is idle full rate channel, assign the channel directly.
� When there is no idle full rate channel in the cell, but there is idle couple
channel, convert the couple channel to full rate channel and then assign the
converted full rate channel.
� When there is no idle full rate channel and idle couple channel in the cell, but
there is idle single channel, check whether the number of single channel in
the cell is more than one. If yes, initiate intracell handover to form a couple
channel and then convert the couple channel to full rate to assign.
� Otherwise, reject the assignment request.
Page24Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
Yes
Yes
Yes
No
No
No
Assignment request
for TCHF only
Full rate available?
Couple channel
available?
More than one half
rate channel?
Request reject
Assign full rate channel
Convert couple channel to full
rate channel and then assign
the converted channel
Initiate intra-cell handover to
form couple channel, and then
convert the couple channel to
full rate channel to assign
Start
End
Page25Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
� If the channel assignment request is to half rate only :
� When there is idle single channel in the cell, assign the idle half rate channel
on the single channel directly.
� When there is no idle single channel in the cell, but there is idle couple channel
in the cell, assign the idle half rate channel on the couple channel.
� When there is no idle single channel and idle couple channel in the cell, but
there is idle full rate channel in the cell, convert the full rate channel into couple
channel and then assign the idle half rate channel on the couple channel.
� Otherwise, reject the request.
Page26Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
Yes
Yes
Yes
No
No
No
Half rate assignment request
Single channel available?
Couple channel available?
Full rate channel available?
Assignment fails
Assign half rate channel
Assign the half rate channel
on the couple channel
Convert the full rate channel
into couple channel and
then assign the half rate
channel on it
Start
End
Page27Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
� If the channel assignment request is to choose the full rate channel
preferentially:
� When there is idle full rate channel in the cell, assign it directly.
� When there is no idle single channel in the cell, but there is idle couple channel
in the cell, convert the couple channel into full rate channel and then assign it.
� When there is no idle full rate channel and couple channel in the cell, check
whether the number of adjustable half rate channel in the cell is more than one.
If yes, initiate intracell handover to form a couple channel and then convert the
couple channel to full rate to assign
� Otherwise, assign the idle half rate channel on the single channel.
Page28Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Rate Adjustment Flow
Yes
Yes
No
No
No
Yes
Assign request for full rae preferentially
Full rate available?
Couple channel available?
More than one half rate
channel?
Assign full rate channel
Convert the couple channel
into full rate channel to
assign
Form couple channel by
intracell handover and then
convert couplechannel into
full rate to assign
Start
End
Assign request for full rae preferentially
Page29Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� First configure the BIE as half rate networking.
Page30Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� Configure the system information
Page31Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration � Configure the parameters for TRX
Page32Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� Configure whether channel rate is adjustable
Page33Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
Page34Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� TCH Traffic Thrsh(%)
� Content:During the allocation of BSC channel, if the
occupation rate of the current channel reaches or exceeds this
threshold, the dual rate user is allocated with half-rate channel
preferentially. Otherwise, allocate the full-rate channel
preferentially.
� Value range:0-100
� Recommendation:50
Page35Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� Enhanced Chan. Convert Enable
� Content:Determines whether to allow handing over the call on
the SINGLE and then trigger the adjustment when converting
half-rate channel into full-rate channel.
� Recommendation: selected
Page36Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
Page37Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
HR Data Configuration
� Chan. Conversion Timer(100ms)
� Content:This timer measures the waiting time for the channel
conversion during call establishment. If the channel conversion
does not complete within the time, the call is cleared and the
timer counts the timeout times.
� Value Range:20-255
� Recommendation:30
Page38Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. EFR
2. HR
3. AMR
Page39Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of AMR
� The Adaptive Multi Rate (AMR) is a set of multiple voice
Codec algorithms. The BTS and MS can automatically
choose a proper Codec algorithm according to the actual
radio environment to adjust the rate. Thus the voice quality
can be improved. Different Codec algorithm generates
different rate voice code stream.
� The AMR is only used in voice service. It is not used in the
data service or signaling service. Thus, the AMR is not
considered when process the signaling of data service or
signaling service.
Page40Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
The Function of AMR� The core thought is that compromise and balance shall be realized between
the channel coding and source coding in sharing the bandwidth of wireless air
interface (the full rate channel 456/20 = 22.8Kbit/s, and the half arte channel
is at 11.4Kbit/s).
� When interference increase is detected at the network side and it exceeds a
certain threshold, the voice coding rate will be reduced automatically. In other
words, some useful voice information is removed. The redundancy of voice
coding is added on condition of the unchanged transmission bandwidth. As a
result, distortion of the voice recovered at the receiver side may rise. The
error rate falls because elements for error check and correction increase. It
prevents the voice quality from deteriorating sharply.
� The AMR coder selects one from multiple rates in real time according to the
channel type (full rate or half rate). By so doing, the optimal combination of
the voice coding and channel coding to satisfy the transient wireless channel
condition and local capacity requirement.
Page41Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR
� The core functions of the AMR are to provide multiple voice Codec
algorithms and automatically choose of voice coding rate according to
radio communication quality.
� Full Rate AMR
It supports full rate channel AMR voice coding and decoding and includes
8 voice rates: 12.2k (GSM EFR), 10.2k, 7.95k, 7.40k (IS-641), 6.70k,
5.90k, 5.15k, 4.75k;The full rate AMR can adjust the coding rate according
to the radio quality indication (RQI). The coding rate is adjusted in the
active coding set (ACS).
� Half Rate AMR
It supports half rate channel AMR voice coding and decoding and includes
5 voice rates: 7.40k (IS-641), 6.70k, 5.90k, 5.15k, 4.75k;The half rate
AMR can adjust the coding rate according to the radio quality indication
(RQI). The coding rate is adjusted in the ACS.
Page42Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
E xpe r im e nt 1 a - Te s t R e s ults
1.0
2.0
3.0
4.0
5.0
C o n d i t i o n s
M O S
EFR
12.210 .2
7.95
7.46.7
5.95.15
4.75
EFR 4.01 4 .01 3 .65 3 .05 1.53
12 .2 4.01 4 .06 4 .13 3 .93 3 .44 1.46
10 .2 4.06 3 .96 4 .05 3 .80 2.04
7.95 3.91 4 .01 4 .08 3 .96 3.26 1 .43
7.4 3.83 3 .94 3 .98 3 .84 3.11 1 .39
6.7 3.77 3 .80 3 .86 3.29 1 .87
5.9 3.72 3 .69 3.59 2 .20
5.15 3.50 3 .58 3.44 2 .43
4.75 3.50 3 .52 3.43 2 .66
No Er rors C/I=16 dB C/I=13 dB C/I=10 dB C/I= 7 dB C/I= 4 dB C/I= 1 dB
MOS (Mean Opinion Score)
AMR
Page43Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Call Set Up Process
Y
Deciding whether to assign
channel that supports AMR
function
Finishes AMR call set up
Deciding whether to
support AMR functionNormal Call
N
BSC receives the assigning
request sent by MSC
Y
NNormal Call
Page44Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� When the call is just set up, the rate configured in “starting
mode” will be adopted.
� MS/BTS automatically adjust the current voice codec rate
based on a certain algorithm and the RQI.
� In AMR, the number and range of adjustable rates depend
on the activated code set. In accordance with the protocol, 4
activated code sets at most can be supported.
Page45Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� The AMR coding rate adjustment means the coding rate is
judged and adjusted based on the MS reported RQI (call
carrier-to-interference ratio).
� When RQI is high, it will be adjusted to a high rate. When
RQI is low, it will be adjusted to a low rate.
Page46Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
CODEC_MODE_4
CODEC_MODE_3
CODEC_MODE_2
CODEC_MODE_1
C/I
THR_1 + HYST_1 = THR_MX_Up(1)
THR_1 = THR_MX_Dn(2)
THR_2 = THR_MX_Dn(3)
THR_2 + HYST_2 = THR_MX_Up(2)
THR_3 = THR_MX_Dn(4)
THR_3 + HYST_3 = THR_MX_Up(3)
Page47Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� When MS responds to uplink AMR rate adjustment, it should be the
next voice frame if possible, and not more than three voice frames.
� If rate adjustment crosses the code set, for example, adjustment
from coding rate 1 to coding rate 4, MS continuously adjusts rates. It
adjusts the rate to coding rate 2, then to coding rate 3, and finally to
coding rate 4. There are two voice frames in each process.
� When BS responds to downlink AMR rate adjustment, the rate must
be adjusted in the earliest voice frame, unless BS is under network
control, and MS request need be ignored.
Page48Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� Normally, AMR rate is adjusted step be step. However, it is
adjusted by leaping over steps in the following cases:
� Handover: After handover is completed, MS uses the initial
coding rate, regardless of the coding rate it used previously.
� The AMR configuration request message changes AMR
configuration.
Page49Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� When the uplink code is checked on the BS side, the coding mode
change command is initiated if it is found to reach the above configured
threshold. After converting the coding mode, MS returns the coding mode
indication.
BTS found RQI threshold is met
coding mode change command
coding mode indication
Page50Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Channel Allocation and Rate Adjust
� The downlink code is checked on the MS side. When it is found to reach
the threshold with the same algorithm, MS initiates the coding mode
request. As required, BS ignores this request or immediately responds to
this request. It then sends the coding mode indication to MS.
BTS found RQI threshold is met
coding mode request
coding mode indication
Page51Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Feature
� Activated voice code set: Supporting setting of different ACS,
coding rate adjustment threshold and hysteresis , and initial
coding rate according to cell
� Adding the statistic index of AMR call at the cell level to cell
performance measurement
� Providing the RQI performance statistic function distributed by TA
at the carrier level
� TC support capability can be queried at the BSC maintenance
console: If various voice code algorithms are supported
Page52Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
AMR Feature
� Supporting dynamic configuration of the Activated Code Set (ACS)
and threshold used for the cell, enabling or disabling it (dynamic
configuration does not affect the established AMR call)
� Supporting real time query about the coding mode currently used
for the specified channel: the system can output the used coding
mode and C/I information (indicating RQI) in the queried period
� Providing the user’s cell capacity and quality equalization control
policy by realizing the HR-FR handover in cell based on RQI
� Adopting different power control parameters for AMR call and non
AMR call, keeping the algorithm consistent
Page53Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
� To enable the AMR function, it is a must to set “Allow full rate
voice coding and decoding algorithm 3” and “Allow half rate voice
coding and decoding algorithm 3” at MSC configuration. In
addition, it is necessary to configure the phase flag of A interface
protocol to PhaseII+.
� Configure the following data at BSC: the A interface circuit to
support the AMR function. As described in the protocol, the circuit
pool number indicates the support capability of the voice codec.
To support the AMR function, it is recommended to configure the
circuit pool to 27. The configuration interface is shown below.
Page54Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
Page55Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
� The circuit support capability configured for the circuit pool
cannot exceed the actual support capability of TC board.
� Check the support capability of TC board from the
maintenance console: Select the TC board through the
maintenance console, and then right click to select “Query
board” from the floating menu. The board querying interface
is shown below.
Page56Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
Page57Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
Page58Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
� If ACS contains four coding rates, “Initial coding mode” can
be configured to 0, 1, 2 or 3. Both of the coding rate
adjustment thresholds and hysteresis is significant and must
be configured correctly.
�The configuration of the coding rate adjustment threshold and
the hysteresis must observe the following rules:
� 0 < th[i] < th[i+1] < 63; i = 1, 2
� 0 < th[i] + hyst[i] < th[i+1] + hyst[i+1] < 63; i = 1, 2
Page59Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
Page60Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Configuration
Page61Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Summary
� In this course,we learn about:
� Master the function of EFR, HR, AMR
� Configuration of EFR, HR, AMR
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