Enhanced Scanning Operation for 802. 16m (sections 15. 2. 6. 11, 15. 2 Document Number: IEEE C802.16m-09/2441 Date Submitted: 2009-11-06 Source: Inuk Jung cooper@lge.com Kiseon Ryu ksryu@lge.com Ronny Yongho Kim ronnykim@lge.com Jin Sam Kwak samji@lge.com LG Electronics Re: Call for comments for Letter Ballot #30a Venue: IEEE Session#64, Atlanta Base Contribution: None Purpose: Discussion by TGm 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 >.

Interruption Time during Scan operation in Rev2 To scan one neighbor BS, the AMS needs 10ms. 5ms for BS switching to the neighbor BS + read preamble 5ms for BS switching back to Serving BS after reading preamble 2

Introduction Proposal The AMS only needs to scan the preamble of the target BSs, which is less then the size of a subframe. However, Rev2 allocates units of frames for scanning a target BS, which implies that a full DL region or UL region will not be utilized Furthermore, since P-preamble do not aid in synchronization, the AMS shall read the S-preambles. Hence, specific subframe level scanning intervals will allow the AMS to perform more efficient data communication and faster synchronization. Proposal Allocate frame level scanning intervals with interleaving intervals in frame units (no data interruption between frames here) Within a frame level scanning interval, allocate subframe level scanning duration with interleaving intervals within a single frame. (subframe level interruption between frames here)

Overview of Subframe level scanning Hierarchical scanning operation. Frame level to Subframe level. 4

Details of Subframe Level Scanning (SLS) Parameters required for SLS Scan duration – 3bits (Scope: SCN-RSP) Number of subrames to scan at neighbor BS Start frame – 1bit (Scope: SCN-RSP) The specific starting point for scanning within a superframe. The end point will be the scanning interval value in addition of this value. Since the AMS has to receive the SFH, and while the Primary-Preamble does not aid synchronization, the AMS shall only scan the secondary-Preambles. If 0, the first S-preamble is to be scanned as the scanning initiating point. If 1, the second S-preamble is to be scanned as the scanning initiating point. (i.e. preamble location within a superframe  [s][p][s][s]) Frame configuration information – x_bits (Scope: SCN-RSP) For scanning mixed mode BSs, the frame offset need to be known to be able to correctly locate the preamble for correct scanning. This is required in case the location of preambles among ABS are different, since ABS 16m-only and mixed mode systems may have different frame configuration. AMS’s BS switching time (Scope: SBC-REQ, SCN-REQ) The timer required to reconfigure AMS’s RF for scanning a neighbor BS This also may differ with the amount of reconfiguration in terms of frequency distant (i.e. if neighbor BS operates in a contiguous frequency, BS switching time will be small, whereas if neighbor BS operates in a distant non-contiguous frequency, BS switching time may be larger) 5

Subframe Level Scanning (SLS) Procedure AMS requests Scanning with parameters for general scanning via the AAI_SCN-REQ message ABS may coordinate the AMS with scanning operation in explicit or unsolicited manner via the AAI_SCN-RSP. ABS includes the following parameters required for SLS operation: Start frame offset, scan duration (subframe level), interleaving interval (subframe level), frame configuration of neighbor BS (only if required). In addition… If scanning target BS is mixed mode (16e/16m), the S-ABS shall inform the AMS about the offset information of preambles. If scanning target BS operates in non-contiguous frequency domain, which requires long time for radio adjustment, the S-ABS shall take such time into account for allocating the start frame offset time. Also, the start frame offset shall indicate which S-preamble the AMS shall scan (i.e. the 3rd or 4th when frame conf.  [S][P][S][S]). The BS switching time may be a capability varying parameter of AMS. Since this parameter is used for allocating the Start frame offset time for scanning, it shall be included in AAI_SBC-REQ/RSP message. 6

Interruption Time comparison during Scan operation Interruption time during Subframe level Scanning. 7

Proposed Text Remedy #1 On the 80216m_D2, page 121, from line 12 to line 43, add proposed text within 15.2.6.1.2 as follows ----------------------------------------------- Start of Text ------------------------------------------------------- 15.2.6.1.2 AMS scanning of neighbor ABSs The scanning procedure provides the opportunity for the AMS to perform measurement and obtain necessary system configuration information of the neighboring cells for handover decision. An ABS may allocate time intervals to an AMS to seek and monitor suitability of neighbor ABSs as targets for HO in units of subframe. The scan duration constitutes of sub-interleaving intervals and sub-scan duration. Within the sub-scan duration Such time interval during which the AMS scans neighbor ABSs, during which AMS is not available to the serving ABS is referred to as a scanning interval. The ABS may specify the target ABSs or ABS types the AMS shall scan and/or averaging parameters that override the default value defined in DCD (TBD). In case of inter-frequency scanning, since the required BS switching time may vary with frequency distance of target ABSs, the start frame of the sub-scan duration shall take such value into account to successfully read the preamble in subframe level control. An AMS may request an allocation of a scanning interval to an ABS by sending the AAI_SCN-REQ message to scan ABSs. Upon reception of the AAI_SCN-REQ message, the ABS shall respond with an AAI_SCN-RSP message. The AAI_SCN-RSP message shall either grant the requesting AMS a scanning interval or deny the request. Also, the AAI_SCN-RSP shall include the required BS_Switching_Time value in case of inter-frequency scanning. The serving ABS may also send unsolicited AAI_SCN-RSP message to initiate AMS scanning. 8

Proposed Text Figure xx ----------------------------------------------- End of Text ------------------------------------------------------- 9

Proposed Text Remedy #2 On the 80216m_D2, page 49, table 681 and 682, add proposed text within 15.2.6.11 as follows ----------------------------------------------- Start of Text ------------------------------------------------------- 15.2.3.12 AAI_SCN-REQ Name Value Usage … Scan duration 8 Duration in frames. Sub-scan duration 3 Number of subframes within the scan duration, during which the AMS scans the Nbr_BS being unavailable at the S-BS. Interleaving interval Scan iteration Number of scan iterations 10

Proposed Text 15.2.3.13 AAI_SCN-RSP ----------------------------------------------- End of Text ------------------------------------------------------- Syntax Size (bit) Notes … Start frame 8 Scan duration Duration in frames. Sub-scan duration 3 Number of subframes within the scan duration, during which the AMS scans the Nbr_BS being unavailable at the S-BS. Notes: This value shall be greater than or equal to requested sub-scan duration in AAI_SCN-REQ Interleaving interval Scan iteration Number of scan iterations For( each ‘1’ in Nbr_Bitmap_Index ) { Nbr_Frame_offset The relative frame offset value of the Nbr_BS in subframe units (max 8 subframes). In case the Nbr_BS has different frame configuration to the S-ABS, the Start frame shall take account this frame offset value for correct frame (preamble) alignment during scanning. If this value is 0, it implies that the Nbr_BS is well aligned with the S-ABS. If (Nbr_Frame_offset != 0) Frame_configuration_information If the frame offset of the NBR_BSis different from the S-ABS, the BS type is different and so will be the frame configuration (mixed mode, 16m only mode, YBS etc). This information includes the related frame configuration information (details of what to include is TBD). This may also be included as a TLV. Nbr_Scanning_start_frame 1 The specific starting point for scanning within a superframe. The end point will be the scanning interval value in addition of this value. Since the AMS has to receive the SFH, and while the Primary-Preamble does not aid synchronization, the AMS shall only the secondary-Preambles. If 0, it means that the first S-preamble is to be scanned as the scanning initiating point. If 1, it means that the second S-preamble is to be scanned as the scanning initiating point. 11