1. A transmission scheme of DL Control information
for Multi-carrier support in IEEE
IEEE Presentation Submission Template (Rev. 9)
Document Number:
IEEE S802.16m-08/955
Date Submitted:
Source:
Nan Li, Min Liu, Changyin Sun, Wenhuan Wang,
Ruixia Zhang, Huiying Fang, Yuqin Chen Voice: [Telephone Number (optional)]
ZTE Corporation
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Venue:
Re:Multi-Carrier Operation; in response to the TGm Call for Contributions and Comments m-08/033 for Session 57
Base Contribution:
IEEE C802.16m-08/955r1
Purpose:
To be discussed and adopted by TGm for use in the IEEE m SDD.
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2. Background
Carriers of a multi-carrier system may be configured as fully configured carrier and partially configured carrier in SDD:
Fully configured carrier: A carrier for which all control channels including synchronization, broadcast, multicast and unicast control signaling are configured. Further, information and parameters regarding multi-carrier operation and the other carriers can also be included in the control channels.
Partially configured carrier: A carrier with only essential control channel configuration to support traffic exchanges during multi-carrier operation.
PBCH and SBCH are used to transmit essential system parameters and system configuration information.
DL control information also includes extended system parameters and system configuration information, control and signaling for DL notifications and control and signaling for traffic.

3. Problems
How PBCH, SBCH and other DL control information are configured on fully configured carriers and partially configured carriers ?
Needs a clarification about the configuration of DL control information on these two kinds of carriers for the benefit of system overhead reduction and improvement of transmission efficiency.
In the case partially configured carrier has SCH, the MS could not acquire complete control and system information after finishing synchronization and has to scan other DL frequency again. There will be long access delay if MS has to decode the whole BCH information to find the configuration of the carrier.
This contribution proposes a Superframe control header（SFCH）to solve this problem.

4. BCH Considerations in multi-carrier system
PBCH solution
All the MSs in a cell complete network entry through fully configured carriers.
Each fully configured carrier needs to be configured with PBCH.
MS gets deployment-wide common information during Initialization State.
After network entry, if the serving BS assigns partially configured carriers to MS as secondary carriers or do carrier switch for the purpose of system load balancing or QoS requirement according to the MS’s multi-carrier capability, MS may use the PBCH information acquired during network access.
PBCH information could only be sent on fully
configured carriers with fixed length.

5. BCH Considerations in multi-carrier system
SBCH solution
SBCH information may change along with the sector’s configuration and the carrier’s operation.
Single-radio MS
If uses a partially configured carrier as its secondary carrier, MS should return to its primary carrier periodically or event-triggered for maintaining control by the BS, therefore, the SBCH information may be sent on partially configured carrier for the convenience of MS’s work.
Information about initial ranging may not be sent on partially configured carrier since it would not be used for the purpose of access.
Multi-radio MS
May simultaneously working on one or more fully configured carriers and /or partially configured carriers, thus the SBCH information may be configured only on fully configured carriers.
Two methods to send SBCH information could be applied.

6. BCH Considerations in multi-carrier system
SBCH solution
Option 1
Configured on both fully configured carrier and partially configured carrier.
Option 2
Configured only on fully configured carriers. SBCH information about partially configured carriers will be sent by one or more fully configured carriers MS is working with in the following three ways:
Unicast
A partially configured carrier is assigned to MS, or traffic switches from one partially configured carrier to another.
Information may be a complete one or just information different from the current carrier.
Multicast
A group of MSs which work on the same fully configured carrier and have been assigned the same target partially configured carrier.
Broadcast

7. DL control information configuration on fully/partially carrier
Channel
Carrier configuration
Essential system parameters and system configuration information
Deployment-wide common information
PBCH
Fully
Downlink sector-specific information
SBCH
Partially
Uplink sector-specific information
Extended system parameters and system configuration information
FFS
Control and signaling for DL notifications
Control and signaling for traffic
USCCH

8. Superframe control header (SFCH)
16m Superframe control header (SFCH)
Transmitted in every Superframe
Predefined transmission format , length and MCS
Fixed location : may be TDM with SCH and followed by BCH.
MS can decode SFCH without any other information.

9. Superframe control header (SFCH)
SFCH format
Only fully configured carriers need to be configured with PBCH.
PI : specify the existence of PBCH. PI=1 means PBCH is present.
PBCH is transmitted using predetermined scheme with fixed length and right after the SFCH, if PI=1.
SI and SBCH length: indicate the presence and the size of SBCH, which should be known by MS before decoding SBCH.
Syntax
Size
Notes
PBCH indicator (PI) 1
0: PBCH is not present
1: PBCH is present
SBCH indicator(SI)
0: SBCH is not present
1: SBCH is present
SBCH length
Reserved
MS only needs to decode SFCH after synchronization to determine whether the current carrier is fully configured and continue to decode the whole BCH.

10. Proposed SDD text
19.x DL broadcast information for Multi-carrier support
Each fully configured carrier needs to be configured with PBCH. After network entry, the serving BS may assign another carrier to MS as secondary carrier or do carrier switch for the purpose of system load balancing or QoS requirement according to the MS’s multi-carrier capability. PBCH information could only be sent on fully configured carriers with fixed length.

11. Proposed SDD text
SBCH information may be transmitted through either of the following two
options:
Option 1:
SBCH can be configured on both fully configured carrier and partially configured carrier.
Option 2:
SBCH can be configured only on fully configured carriers. SBCH information about partially configured carriers will be sent by one or more fully configured carriers MS is working with.

12. Proposed SDD text 19.x.1 Superframe control header (SFCH)
A Superframe control header (SFCH) is used to indicate the configuration of a carrier in the case that partially configured carrier has SCH. A PBCH indicator (PI) Bit in SFCH specifies the existence of PBCH. PI=1 means PBCH is present. PBCH is transmitted using predetermined scheme with fixed length and right after the SFCH, if PI=1. SFCH indicator（SI）Bit and SBCH length are used to indicate the presence and the size of SBCH. SFCH should be transmitted with predefined transmission format, length, MCS and location . SFCH may be TDM with SCH and followed by BCH.

13. Proposed SDD text The structure of SFCH is shown in Table 1.
Table 1 SFCH format
Syntax
Size
Notes
PBCH indicator (PI) 1
0: PBCH is not present
1: PBCH is present
SBCH indicator(SI)
0: SBCH is not present
1: SBCH is present
SBCH length
Reserved