Multi-Carrier – Preambles for Fully/Partially Configured Carriers
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-08/1093
Date Submitted:
2008-09-05
Source:
Zexian Li
Nokia E-mail: zexian.li@nokia.com
Xin Qi, Joon Chun, Boariu Adrian, Yousuf Saifullah
Peter Wang
Nokia Siemens Networks E-mail: xin.qi@nsn.com
Venue:
Re: Multi - Carrier Operation: PHY . in response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57.
Base Contribution:
This is the base contribution.
Purpose:
To be discussed and adopted by TGm for the 802.16m SDD
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 >.

– 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 essential control channel configuration to support traffic exchanges during multi-carrier operation.

• Two deployment scenarios defined in Section 19.1
:
– Scenario 1 : All carriers in the system are fully configured to operate standalone and may support some users as their primary carrier.
– Scenario 2 : In addition to fully configured and standalone RF carriers the system utilizes supplementary radio carriers optimized as data pipes for certain services or traffic types using limited control signaling capability.
Such supplementary carriers may be used only in conjunction with a primary carrier and cannot operate standalone to offer 802.16m services for a MS.
• Preamble should be transmitted in all RF carriers no matter they are primary or secondary in order that MS can get synchronized, at least in the cases with
• Scenario 1.
• where the RF carriers are located in non-contiguous BW.

• Network entry latency is an issue in Scenario 2:
– In Scenario 2, the latency of MS entering network is an issue. This is because partially configured (or supplementary) carriers may not offer service for a MS which means the MS has to find out the fully configured carriers in order to set up service flows .
– The problem is during network entry, MS does not know which carriers are fully configured and which are partially configured.
MS will search all the preambles and try to synchronize with the BSs. MS may find the first preamble belonging to partially configured RF carrier. Since MS can not find some specific control channels e.g. initial ranging channel, MS has to continue search until the fully configured carrier is found.
• Network entry latency can be reduced if the MS can differentiate fully configured and partially configured carrier as early as possible.
(of course in Scenario 1, this is not a problem since all carriers are fully configured).
• This contribution proposes solutions to reduce unnecessary network entry latency .

• Solution #1 : Applying different preambles to fully configured and partially configured RF carriers. Different ways to achieve the goal:
– classify the preambles into two groups:
• preamble group for fully-configured carriers
• preamble group for partially-configured carriers
– or separately design preambles for fully-configured and partiallyconfigured carriers
– The numbers of preambles in the two groups can be same or different.
• Pros
– Number of preamble sequences in the searching space is reduced since
MSs just search for preambles dedicated to fully-configured carriers.
– It is possible that different partially-configured carriers share the same preamble sequence.
• Cons
– Number of preamble sequences need to be increased which should not be an issue since anyway the number of preamble sequences need to be increased due to e.g. femto-BS support etc.
Simple and efficient, almost without additional efforts

• Solution #2 : The partially configured carrier can include carrier frequency/preamble information of the fully configured carrier of the same BS.
– The information can be included in the broadcast channel (BCH) and/or broadcast messages . In additional to this, there should be indication in broadcast channel/message to tell MS the current carrier is partially-configured and there is information about fullyconfigured carrier in the broadcast channel/message.
– Or the information can be exchanged during e.g. ranging phase in case there is initialing ranging region in the partially-configured RF carriers.
• Pros
– If the same preamble sequence is employed at fully-configured and partially-configured carriers, the searching space is the same as Solution #1.
• Cons
– If preamble sequences used by partially configured RF carriers are different from fully-configured RF carriers, searching space is increased resulting in extra complexity.
– MS needs to get synchronized with partially configured carrier before getting access to fully configured carrier, compared to Solution #1, this can bring additional latency , especially if the information is conveyed via ranging process.
Workable with additional latency

• Network entry procedure in multi-carrier case needs to be designed based on normal single carrier case.
• In Scenario 1, if all RF carriers are fully configured, network entry procedure is not much different to the normal network entry except the allocated resource can be in other carriers.
• In Scenario 2:
– If different preambles are used for partially configured and fully configured carriers:
• MS can synchronize with fully configured carriers by just searching preambles dedicated to fully configured carriers
• Rest of procedures are same as scenario 1.
– If there is no separation of preambles
• MS has to synchronized with both fully configured and partially configured carriers, only after reading some MAC management messages or ranging process or after some Timer expires, MS tries to access network from other carriers.
NNSN proposes to adopt Solution #1 which is simple but efficient.

All partially and fully configured RF carriers transmit preambles, when they are located in non-contiguous bandwidth or with deployment Scenario 1 defined in
Section 19.1.
With deployment Scenario 2 defined in Section 19.1, preamble sequences can be classified into two groups: one group is dedicated to fully configured carriers and another one is dedicated to partially configured carriers .