Discussion of Explicit vs. Implicit PC-A-MAP IE Assignment
(15.2.3)
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number: IEEE S802.16m-09/2584
Date Submitted:
2009-11-06
Source:
Yi Hsuan, Rongzhen Yang, Hujun Yin
Intel Corporation
Venue:.
IEEE 802.16m: “802.16m/D2 letter ballot”
Target topic: P802.16M/D2 - 15.2.3
Purpose:
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Background
• In current P802.16M/D2, the text of PC-A-MAP IE
assignment for CLPC is not ready;
• In previous meetings, the implicit assignment methods
were proposed (C80216m-09/1054 and C80216m09/1903):
– It claims the benefit for signaling overhead saving
– But it limits the flexibility of PC-A-MAP IE assignment for period,
power adjust step and CLPC enable/disable;
• Here we share our study of 16m CLPC usages, to
identify the suitable solution for PC-A-MAP IE
assignment.
Evaluation Setting
• Key Assumption:
– CLPC should at least support power tracking at for
different speed:
• Three moving speeds are selected for analysis: 3km/h,
30km/h and 120km/h with 16m e-ITU channel;
• It is considered as “following” of CLPC when error is less
than deltastep/2; (deltastep = 0.5 dB);
• Evaluation Parameters Setting:
– Set different periods for CLPC control rate for different
moving speeds, to identify the minimum period of
each scenarios;
– Set different CLPC power adjust step (deltastep) for
different moving speeds, to identify the best step size
of each scenarios;
Moving Speed: 3km/h
Example of Power Tracking
Absolute Error CDF
1
9
10frame
Shadowing
8
0.9
10frame
20frame
20frame
30frame
0.8
30frame
6
0.7
5
0.6
F(Error)
dB
7
4
0.5
3
0.4
2
0.3
1
0.2
0
0.1
0
-1
0
100
200
300
Time(s)
400
500
600
0
1
2
3
4
5
6
7
8
9
Error
• CLPC Power Control Step Size (0.5dB) of 2 bits: -0.5, 0, +0.5, 1 dB
• Period of 20 frames with 0.5dB adjust step can effectively tracking
channel fading (following probability with 90%)
Moving Speed: 30km/h
Absolute Error CDF of
Step Size (0.5dB) of 2 bits: -0.5, 0, +0.5, 1 dB
Absolute Error CDF of
Step Size (1dB) of 2 bits: -1, 0, +1, 2 dB
1
1
2frame
1frame
0.9
0.9
2frame
4frame
8frame
3frame
0.8
4frame
0.7
0.7
0.6
0.6
F(Error)
F(Error)
0.8
0.5
0.5
0.4
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0
0
0
2
4
6
8
Error
10
12
14
0
2
4
6
8
10
Error
• 2 choices can meet 90% following requirement:
– Period of 2 frames with 0.5dB adjust step
– Period of 5 frame with 1dB adjust step
12
Moving Speed: 120km/h
Absolute Error CDF of
Update Period 1 Frame
Absolute Error CDF of
Update Period 2 Frame
1
1
0.5dB
0.9
0.5dB
0.9
1dB
1dB
2dB
0.8
0.8
0.7
0.7
0.6
0.6
F(Error)
F(Error)
2dB
0.5
0.5
0.4
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0
0
0
2
4
6
Error
8
10
12
0
2
4
6
8
10
Error
• CLPC Power change in every frame is needed
• Adjust step 1dB (-1, 0, +1, 2) is better than
0.5dB & 2dB
12
Summary of CLPC
Power Tracking Evaluation
• The CLPC power control rate should be
configurable for the different MS.
• The CLPC power control change step can be
configurable for the different MS, 2 options are
enough: minimum step = 0.5 or 1 dB.
• Current implicit assignment cannot support
upper 2 requirements.
Supporting of Open Loop and Closed Loop Coupling
High Traffic
Fast control
Slow control
Fast
control
Slow control
Fast control
• Coupling of Open Loop and Closed Loop Power Control is defined
at SDD 11.10.2.3:
– Open Loop Power Control coarsely adjust uplink transmit power with
low signaling overhead
– When there is high traffic, Closed loop will be the main power control
scheme
• Explicit vs. Implicit Assignment:
– Explicit Assignment can implement it easily by a field of Assignment
Duration (frames)
– Currently, there is no implicit assignment method that can support it.
Recommendation
• PC-A-MAP IE Assignment should be
explicit to include at least 3 fields:
– Control Rate (assignment period)
– Power Change Step: 1 bit field to indicate 0.5
or 1 dB
– Assignment Duration: the begin and the end
of assignment
• The proposed text in contribution xxxx and
its latest version is recommended.