IEEE 802.16m Supporting Femtocell Low Duty Cycle Mode Document Number: IEEE C80216m-09_0459 Date Submitted: 2009-02-27 Source: Ying Li, Zhouyue Pi, Baowei Ji, Email: yli2@sta.samsung.com Phone: +1-972-761-7903 Jung Je Son, Anshuman Nigam Samsung Electronics Venue: IEEE Session #60 Base Contributions: Re: Change Request for IEEE 802.16m SDD, Section 17 Purpose: Discussion and Approval Notice: This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.

Low duty cycle mode for open femtocells In current SDD, LDC mode is only for CSG femtocells “Besides the normal operation mode, CSG Femtocell BSs may support Low-duty Operation Mode, in order to reduce interference to neighbor cells.” Propose: LDC mode should be also available for open femtocells For an open femto BS, it also has chances to have no active user in its coverage, due to smaller coverage of femtocell If open femtocells have LDC mode, it can help reduce interference to neighbor cells as well. LDC for open femtocell can save energy as well.

FA information to help MS scan femtocells in LDC mode (1/4) Frequency allocation (FA) of femtocells is the key information an MS needs to shorten the time of searching for femtocells MS knowing the active timings of LDC of femtocells can help MS search for femtocells Combine them Femtocells with the same FA use the same active timing and MS scans correspondingly Femtocells with different FA use different active timing and MS scans correspondingly A mapping of FA to LDC pattern in broadcast channel

FA information to help MS scan femtocells in LDC mode (2/4) Femtocells with the same FA use the same active timing and MS scans correspondingly AI UAI time Femto1 @ FA1 Regular mode Femto2 @ FA2 LDC mode Femto3 @ FA2 Scan others MS FA2 Preamble AI: available interval UAI: Unavailable interval

FA information to help MS scan femtocells in LDC mode (3/4) Femtocells with different FA use different active timing and MS scans correspondingly AI UAI time Femto1 @ FA1 Regular mode Femto2 @ FA2 LDC mode Femto3 @ FA3 FA3 Scan others MS FA2 Preamble others AI: available interval UAI: Unavailable interval

FA information to help MS scan femtocells in LDC mode (4/4) Macrocell may broadcast a mapping of femtocell FA to LDC pattern If a mapping is predefined by the system, macrocell may only need to broadcast femtocell FAs, and MS can generate femto LDC patterns using the predefined mapping once knowing FAs. Femtocell FAs and LDC patterns may be written in MS white list. Femtocell FA1 LDC Pattern 1 Femtocell FA2 LDC Pattern 2 Femtocell FA3 LDC Pattern 3

Proposed text 17.7 Low duty cycle operation mode To reduce the interferences to others, femtocells (OSG, CSG) may support low duty cycle operation mode. To help MS scan femtocells in low duty cycle mode, femtocell frequency allocations (FAs) may be mapped to patterns of low duty cycle, and femtocell FAs and patterns of low duty cycle may be broadcast over the air.