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All Rights Reserved © Alcatel-Lucent 2007
SOURCE: Dennis Ong, Alcatel-Lucent John Burgess Alcatel-Lucent
CONTACT: hdong@alcatel-lucent.comjkburgess@alcatel-lucent.com
ABSTRACT: This contribution discusses where we are with IS-2000 3G1x Femto system selection, and what we need to look for in a solution.
TITLE: Femtocell System Selection
3GPP2 Femto Cell Workshop
RECOMMENDATION: <Discuss / FYI >
Alcatel-Lucent grants a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. Alcatel-Lucent is also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution.This document has been prepared by Alcatel-Lucent to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Alcatel-Lucent. Alcatel-Lucent specifically reserves the right to amend or modify the material contained herein and to any intellectual property of Alcatel-Lucent other than provided in the copyright statement above.
S00-FEMTO-20070915-008<Femtocell System Selection>
All Rights Reserved © Alcatel-Lucent 20072 | October 15-16, 2007
Technical Discussion: System Selection
How does an IS-2000 mobile find the Femto? Depending on deployment, same carrier or dedicated carrier
Most cases will behave like dedicated carrier, since the Macro will typically have more carriers than the Femto
Idle mode General Neighbor List (GNL) message on Macro has frequency information
of Femto neighbors As long as the Femto EC/I0 is 3dB stronger than the Macro EC/I0, the IS-2000
mobile will perform the idle hand-off If the Femto is located too close to an unloaded Macro, this condition may
fail Active mode (future)
Macro can direct mobile to search other frequencies using Candidate Frequency Search (CFS)
IS-95 (pre-IS-2000) 2G mobiles cannot receive either the GNL or CFS message, will not be able to find most Femtos Femto on dedicated carrier, or Femto on macro carrier, not the one hashed to by 2G mobile
All Rights Reserved © Alcatel-Lucent 20073 | October 15-16, 2007
Technical Discussion: System SelectionWhere is the Femto is located too closely to Macro, key to colors
Direct Line-of-Sight
-1000 -500 0 500 1000-1000
-800
-600
-400
-200
0
200
400
600
800
1000
x [m]
y [m
]
Pmacro = 16W, rmacro = 1033m, Pfemto,max = 50mW, Channel: freespace
femtocells that achieve target rangereduced range (34.8%)reduced range: 15dB macro & 7.5dB femto wall sep. (6.2%)reduced range: 15dB macro wall separation (1.1%)
Femto Achieves Full Range (Blue)
Femto Reduced Range (no penetrationlosses)
Femto Reduced Range, penetrationLosses:15dB external wall for Macro 7db internal wall for Femto
Femto Reduced Range, penetrationLosses: 15dB external wall for Macro
All Rights Reserved © Alcatel-Lucent 20074 | October 15-16, 2007
Technical Discussion: System Selection
Where is the Femto is located too closely to Macro? Urban Direct Line-of-Sight
Femto 50 mW
PCS 16W Half the size of
Cellular cell below
Cellular 20W
-1000 -500 0 500 1000-1000
-800
-600
-400
-200
0
200
400
600
800
1000
x [m]
y [m
]
Pmacro = 16W, rmacro = 1033m, Pfemto,max = 50mW, Channel: typical urban
femtocells that achieve target rangereduced range (1%)reduced range: 15dB macro & 7.5dB femto wall sep. (0.4%)reduced range: 15dB macro wall separation (0.1%)
-1000 -500 0 500 1000-1000
-800
-600
-400
-200
0
200
400
600
800
1000
x [m]
y [m
]
Pmacro = 16W, rmacro = 1033m, Pfemto,max = 50mW, Channel: freespace
femtocells that achieve target rangereduced range (34.8%)reduced range: 15dB macro & 7.5dB femto wall sep. (6.2%)reduced range: 15dB macro wall separation (1.1%)
-2000 -1500 -1000 -500 0 500 1000 1500 2000
-2000
-1500
-1000
-500
0
500
1000
1500
2000
x [m]
y [m
]
Pmacro = 20W, rmacro = 2321m, Pfemto,max = 50mW, Channel: typical urban
femtocells that achieve target rangereduced range (0.2%)reduced range: 15dB macro & 7.5dB femto wall sep. (0.1%)reduced range: 15dB macro wall separation (0%)
-2000 -1500 -1000 -500 0 500 1000 1500 2000
-2000
-1500
-1000
-500
0
500
1000
1500
2000
x [m]
y [m
]
Pmacro = 20W, rmacro = 2321m, Pfemto,max = 50mW, Channel: freespace
femtocells that achieve target rangereduced range (8.6%)reduced range: 15dB macro & 7.5dB femto wall sep. (1.3%)reduced range: 15dB macro wall separation (0.3%)
All Rights Reserved © Alcatel-Lucent 20075 | October 15-16, 2007
Technical Discussion: System Selection
Where is the Femto is located too closely to Macro? Countryside Direct Line-of-Sight
Femto 50 mW
PCS 16W Half the size of
Cellular cell below
Cellular 20W
-5000 0 5000
-5000
-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
5000
x [m]
y [m
]
Pmacro = 16W, rmacro = 5790m, Pfemto,max = 50mW, Channel: countryside
femtocells that achieve target rangereduced range (0%)
-5000 0 5000
-5000
-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
5000
x [m]y
[m]
Pmacro = 16W, rmacro = 5790m, Pfemto,max = 50mW, Channel: freespace
femtocells that achieve target rangereduced range (1.4%)reduced range: 15dB macro & 7.5dB femto wall sep. (0.2%)reduced range: 15dB macro wall separation (0.1%)
-1 -0.5 0 0.5 1
x 104
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1x 10
4
x [m]
y [m
]
Pmacro = 20W, rmacro = 10118m, Pfemto,max = 50mW, Channel: countryside
femtocells that achieve target rangereduced range (0%)
-1 -0.5 0 0.5 1
x 104
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1x 10
4
x [m]
y [m
]
Pmacro = 20W, rmacro = 10118m, Pfemto,max = 50mW, Channel: freespace
femtocells that achieve target rangereduced range (0.3%)reduced range: 15dB macro & 7.5dB femto wall sep. (0%)
All Rights Reserved © Alcatel-Lucent 20076 | October 15-16, 2007
Technical Discussion: System Selection
How to improve the success of idle IS-2000 mobiles finding the right Femto? Without changing the standards or the mobiles
Add Femto beacon pilot on some or all MacroCell Carriers (hopping or not) Will need more than just a pilot to direct idle mobiles to the right carrier
Pros 2G mobiles may find the
Femto MacroCell NL population may
be easier Can allot fewer PN offsets if
Femto main carrier spread over multiple carriers
Cons RF Interference on multiple
carriers FemtoCell cost increases from
additional radio hardware Better chance for mobiles to
idle hand-off to Femtos that do not allow them access
All Rights Reserved © Alcatel-Lucent 20077 | October 15-16, 2007
Technical Discussion: System Selection
How to improve the success of idle IS-2000 mobiles finding the right Femto? Allowing changing the standards and the mobiles
Airvana’s Preferred User Zone List (PUZL) changes
Pros Mobile finds the allowed
Femtos without guesswork Mobile does not spend much
time idling on unavailable Femtos
Cons Will require changes to the air
interface, mobile & network New P_REV
“Black list” may be difficult to maintain at the Macro
All Rights Reserved © Alcatel-Lucent 20078 | October 15-16, 2007
Technical Discussion: System Selection
IS-2000 mobile/Femto system selection still needs more thinking Prefer solutions that do not change the air interface Need a solution for the “exclusion zone”
Especially when there are calls on the Femto
Willing to entertain other solutions ALU working on alternate solutions not yet ready for publication
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