IEEE 802.16m Femto Proposal
Document Number: IEEE S802.16m-08/1260
Date Submitted: 2008-10-31
Source:
Baowei Ji, Bill Semper, Daegyun Kim,
Sudhir Ramakrishna, Kaushik Josiam,
Ying Li, Zhouyue Pi
Samsung Telecommunications America
Email: Baowei.Ji@Samsung.com
Phone: +1-972-761-7167
Jaehee Cho, Youngbo Cho, ChangYoon Oh, ByungWook Jun,
SeongHyeon Chae, Hyunjeong Kang, Rakesh Taori, Anshuman Nigam
Samsung Electronics
Venue:
IEEE Session #58, Dallas, TX.
Base Contributions:
Re:
TGm SDD: Femtocells
Purpose:
Notice:
Discussion and Approval
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Outline
•
•
•
•
Femto Cell-ID Selection
Femto Access Control
Femto Cell Selection
Femto Mobility Management
– Femto-to-Macro HO
– Macro-to-Femto HO
– Femto-to-Femto HO
• Femto Operation Modes
• Femto Inter Working Signal
• Hotzone
2
Femto Cell-ID Selection: Collision Avoidance
Powered on and associated with core
network
Is Cell ID assigned by the
operator?
Yes
No
Obtain the Cell ID of the neighbor
Femto cells
Randomly pick up one from the Cell
ID pool that precludes those being
used by neighbor Femto cells
Normal Operation Mode
3
Femto Cell-ID Selection: Collision Resolution
Normal Operation Mode
Obtain the Cell ID of the neighbor
Femto cells
Is Cell ID colliding with a
neighbor Femto BS?
No
Yes
Randomly pick up one from the Cell
ID pool that precludes those being
used by neighbor Femto cells
Broadcast to MS the switching time
and new Cell-ID to be used;
Switch to new the Cell-ID at the
switching time
4
Femto Access Control
• Closed User Group (CUG)
• Distributed CUG Femto cells
5
Femto Cell Selection
• Consideration
– Mobility
– The combination of Cell-ID and location
– Access privilege
6
MS
Core
Network
Femto BS
MOB_MSHO_REQ
MOB_NBR-ADV
- MOB_NBR-ADV of the
macro BS
MOB_BSHO_RSP
Macro BS
HO-Request
NBR-Info
HO-Request
Context Transfer
Context Transfer
Bearer Path Registration
Bearer Path Registration
HO-Response
HO-Response
HO-Confirm
HO-Confirm
- Station ID pre-update
- TEK pre-update
- Dedicated ranging code
- Exclusive ranging channel
MOB_HO_IND
Femto-to-Macro
HO
SRHO_Ranging_IE() with exclusive ranging channel
Dedicated ranging code over exclusive ranging channel
RNG-RSP (HO Proc. Opt.) and UL grant
Operational (data transfer)
7
MS
Core
Network
Macro BS
MOB_MSHO_REQ
MOB_NBR-ADV
- Dedicated signaling
- MOB_NBR-ADV of the
Femto BS(s)
MOB_BSHO_RSP
Femto BS
HO-Request
NBR-Info
HO-Request
Context Transfer
Context Transfer
Bearer Path Registration
Bearer Path Registration
HO-Response
HO-Response
HO-Confirm
HO-Confirm
- Station ID pre-update
- TEK pre-update
- Dedicated ranging code
- Exclusive ranging channel
MOB_HO_IND
Macro-to-Femto
HO
SRHO_Ranging_IE() with exclusive ranging channel
Dedicated ranging code over exclusive ranging channel
RNG-RSP (HO Proc. Opt.) and UL grant
Operational (data transfer)
8
Femto-to-Femto HO
• Similar to macro-to-macro HO
• Alternatively, broadcast MOB_NBR-ADV on demand
9
Femto Operation Modes (1/2)
• Normal Operation
• Low-duty Operation
HO Request, or
Paging Request, or
Network entry request,
Normal
Operation
Mode
Low-Duty
Operation
Mode
No MS in active
mode
10
Femto Operation Modes (2/2)
HO Request, or
Paging Request, or
Network entry request,
An MS enters the cell
IML++
Normal Operation
Mode
Low-Duty
Operation Mode
IML-An MS leaves the cell
11
IML=0
Inter Working Signal (IWS) Transmission
• Assumption: Femto BS is synchronized to macro BS
• Femto BS transmits IWS at macro BS FA (frequency
assignment) in long period
• An MS can detect the existence of Femto BS without scanning
other FA
• Femto BSs using the same FA transmit IWS in the same
time/frequency region
– Femto BSs operating in different FA  the resource region for IWS transmission is
different
IWS Transmission time
Data: f1
f2
Femto A
f1
Data: f2
IWS: f1
Femto A
Data: f3
f1
Macro BS
f3
Femto B
Data: f2
f2
Femto C
f1
Macro BS
IWS: f1
Femto B
IWS: f1
Femto C
12
Hotzone Operation Model
•
Hotzone is a Femtocell BS open to all 16m subscribers
•
Hotzone Operation Model
–
Hotzones are deployed to increase cell capacity
•
–
Some of them may be deployed outside
Hotzones in macro coverage may operate in the same FA of macro BS
•
It may cause interference
System information for hot zone
is broadcasted
Freq.
f1
Macro-cell
Macro BS @ f1
MS detect the Hot-zone BS @ f1
exist of hot zone
Freq.
f1
Hot-zone
13
Problem Definition & Requirements
•
Problem definition
–
Hotzone coverage may create a coverage hole in the macro cell
•
•
Though Handover may appear to be an acceptable solution, it is not an
effective solution to the above problem because
HO may not always guarantee the connection, considering
–
–
–
–
•
Small size of hot zone
Configuration of deployed hot zone
High speed mobile
How to keep connection for a MS which can’t perform HO to hot
zone?
Requirements to support hot zone
–
Hot zone deployment shall not prevent 16m system from guaranteeing
connection to system
14
Example of reserved resource
Downlink
Robust CH coding
MAP
Macro BS Tx
SFH
MAP
MAP
MAP
MAP
MAP
Tx
MAP
Hot-zone BS Tx
MAP
MAP
MAP
MAP
Null SFH
MAP
Null
Sub-frame offset
of Hot-zone
for ftraffic
resource which
have to be
prevented from
interference of
hot zone
Macro only region – the number of subframes is adaptively adjusted
Uplink
Macro BS Tx
Tx
Macro only region – the
number of sub-carriers is
adaptively adjusted
Hot-zone BS Tx
Null
15
Suggested Text
• Accept the suggested text in C802.16m08/1252.
16