Identifying Femtocells Closed Subscriber Groups in IEEE 802.16m

Document Number: IEEE C80216m-09_2599r1Date Submitted: 2009-11-15

Source: Ying Li, Anshuman Nigam, Email: yli2@sta.samsung.com Phone: +1-972-761-7903Jung Je Son, Zhouyue Pi, Jungshin Park

Samsung Electronics

Venue: IEEE Session #64Base Contributions:

Re: Contribution in support of a comment on LB30a

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Use cases to support• Use cases will direct and shape our specific design• The possibilities of use cases could be, for example,

– 1. Home • E.g., a home owner can buy a femto and open it up only to family

members and friends– 2. Enterprise

• E.g., a company can buy tens/hundreds femtocells to enhance the connectivity, then such femtos can be open only to the company employees

– 3. Membership• E.g., a use can buy a membership of Starbucks, which means all the

femtocells owned by Starbucks should be open to the user– 4. Operator

• E.g., the operator uses femtocells to fix coverage holes, then such femtocells should be open to subscribers of this operator

– And so on.

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Motivation (1/2)• Accessibility of a femto BS

– OSG Femtocell BS: accessible to all MSs– CSG-open femtocell: open to all MSs, but subscriber MS has higher priority, and

non-subscriber MS has best-effort access.– CSG-closed Femtocell BS: only accessible to its authorized MSs, though open to

all MSs for emergency access.

• An MS needs to determine whether it is allowed to access a CSG-closed Femtocell, and whether it is a member or non-member of a CSG-open femto.

• MS locally carries a white list, containing all the common identifier of CSG femtos. Femto broadcasts the information of the common identifier, so that MS can use white list to help for it to know whether it is a member of femto.

• MS needs to know the common identifier to request scanning : In D2, “An AMS may scan femto ABSs based on the CSG white list”

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Motivation (2/2)

• Common ID [called CSG ID] – to ease the management– Several Femtocell BSs could belong to a same CSG entity, which have the

same group of authorized MSs.– Benefits of using a common CSG ID for this set of BSs

Shorten the list of allowable femtocells stored in MS To ease the management at the paging controller, and avoid location update

when the MS is moving inside the CSG. To ease the management of subscriber groups. E.g., an MS subscribes a

membership of Samsung, which has many offices. Consider an enterprise installs a new femto BS in its office,

Without CSG ID, the enterprise has to ask the operator to update it by adding this new femtocell to the white list of all its membership subscribers

With CSG ID, such update is not needed.

Proposed approach• Femto ABS CSG ID is part of the BS ID

– CSG ID can be composed from few or all of the 24 MSB bits of the full BSID and few or all of the 24 LSB bits of the full BSID

– Different operators can have different rules of how the CSG ID is constructed. The rules can be per Operator ID.

– The rules can be pre-provisioned or unicasted.– A default rule can be

• CSG_Type is 26-27th bit of the full BSID counted from the MSB. • If CSG_Type=00, then CSGID=MSB_36 (BSID), large business case• If CSG_Type=01, then CSGID=MSB_40(BSID), medium business case• If CSG_Type=10, then CSGID=MSB_44(BSID), small business case• If CSG_Type=11, then there is no CSGID, home use case

• Advantages– Fast: CSGID can be carried in SFH SP.– Efficient: no overhead for CSG ID– Ease the CSG management

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Proposed Text (1/2) Page 545, line 14, insert the following text as a separate paragraphs. The common identifier is composed from few or all of the 24 MSB bits

of the full BSID and few or all of the 24 LSB bits of the full BSID, thereby enabling it to be implicitly derived from the full BSID. This common identifier is known as the CSG ID.

The information of which bits are designated as the CSG ID can be per Operator ID. It can be pre-provisioned or unicasted during initial network entry in AAI_REG_RSP. Multiple Operator IDs can have the same mapping information.

If such information is not signaled by the BS then the MS can assume specified default values.

A default rule is as follows. The 26-27th bit of the full BSID counted from the MSB is an indication of CSG_Type. If CSG_Type=00, then CSGID is the MSB_36bits of the full BSID, if CSG_Type=01, then CSGID is the MSB_40bits of the full BSID, if CSG_Type=10, then CSGID is the MSB_44bits of the full BSID, and if CSG_Type=11, then there is no CSGID.

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Proposed Text (2/2)

Page 545, line 27, insert the following text as a separate paragraph. AMS’s local white list may contain the allowable BS IDs or common

identifiers of CSGs and relevant information to help derivation of the allowable BS IDs from common identifier.

Page 545, line 32, insert the following text in blue. In addition, an AMS may scan femto ABS based on the CSG white list. AMS

may include the common identifier of the designated CSG femto BSs in AAI_SCN-REQ. When BS receives AAI_SCN-REQ including the BS ID or common identifier of a CSG, the BS may include in AAI_SCN-RSP the other BS IDs belonging to the requested CSG.

Page 545, line 52, insert the following text in blue. ……using an AAI_NBR-REQ message. AMS may include the common

identifier of the designated CSG femto BSs in the NBR-REQ.