IEEE C802.16m_09/0993
Project
Title
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Proposed Text for Network Entry Procedure for IEEE 802.16m Amendment
Date
Submitted
2009-04-27
Source(s)
Jin Lee, Kiseon Ryu, Ronny Yongho Kim,
and Jin Sam Kwak
Voice: +82-31-450-7808
E-mail: {jins978, ksryu, ronnykim} @lge.com
LG Electronics Inc
Re:
802.16m AWD-New Contribution : “Network Entry ”
Abstract
The contribution proposes the text for network entry to be included in the 802.16m amendment.
Purpose
To be discussed and adopted by TGm for the 802.16m amendment.
Notice
Release
Patent
Policy
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represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for
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Unsolicited Bandwidth Allocation For Fast Network Entry
Jin Lee, Kiseon Ryu, Ronny Yongho Kim and Jin Sam Kwak
LG Electronics
1. Introduction
In this contribution, we propose amendment texts for network entry to be incorporated into Amendment
Working Document (IEEE 802.16m-09/0010r1a).
2. Modifications from the SDD and key descriptions
By the current SDD for network entry, 16m network entry procedure is similar to the network entry in 16Rev2.
To reduce entry latency and expedite network entry procedure, this contribution proposes unsolicited bandwidth
grant for MAC management message (re)transmission during network entry.
 AMS uses a bandwidth grant timer to check for allocated bandwidth within the bandwidth grant timer
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IEEE C802.16m_09/0993
interval.
 ABS allocates unsolicited UL grant at a specific time (i.e., When the last HARQ retransmission is failed
or HARQ ACK is received.)
 AMS does not need to perform contention based bandwidth request for (re)transmission.
3. References
[1] IEEE 802.16m-08/003r8, “The Draft IEEE 802.16m System Description Document”
[2] IEEE 802.16m-09/0010r1a, “IEEE 802.16m Amendment Working Document”
[3] IEEE P802.16 Rev2/D9a
4. Proposed fast network entry
4.1 Motivation
In order for AMS to send a message to the ABS, AMS shall request uplink bandwidth for transmission. Since
AMS can not predict when it needs to send messages (/MAC PDU), it is indispensable to request uplink
bandwidth whenever AMS requires to transmit MAC messages.
However, 16m network entry procedure consists of the predicted sequence of message transmission between
AMS and ABS (it is assumed 16m network entry follows procedures described in SDD 10.8). Based on this
nature, if ABS could perform bandwidth grant without AMS’s request during network entry, latency for
completing network entry would be significantly reduced.
Also, AMS may perform retransmission for unsuccessfully delivered messages until a retry counter expires. In
such case, AMS has to request bandwidth before retransmission which could lead to more delay.
Therefore, we propose fast network entry that enables unsolicited bandwidth grant for message (re)transmission
from AMS to ABS.
4.2 Network entry based on Bandwidth Grant AMS timer
Proposed 16m fast network entry proceeds as the following steps:
① AMS synchronizes with ABS via Advanced Preamble (A-Preamble).
② AMS obtains necessary information for network selection via SFH.
③ After receiving ranging response message (success), AMS sends ranging request message and may
request an unsolicited bandwidth grant indicator for next transmissions.
④ ABS responds to AMS with the bandwidth grant indicator which specifies unsolicited bandwidth grant
for message (re)transmission during network entry.
⑤ ABS performs bandwidth grant after successful transmission of ranging response message.
⑥ AMS starts a bandwidth grant timer after AMS sends HARQ ACK (corresponding to ranging response)
and checks out assigned UL bandwidth for specific time duration. (Bandwidth grant interval). AMS
stops the timer when UL bandwidth is granted. If the timer expires without allocation of UL resources,
AMS may request contention based bandwidth for next transmission.
⑦ If allocated, AMS transmits SBC request through allocated bandwidth. When AMS fails to send SBC
request (e.g. upon expiration of maximum HARQ retransmission), AMS retransmits the SBC request at
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IEEE C802.16m_09/0993
unsolicited bandwidth grant (ABS grants AMS UL bandwidth when maximum HARQ retransmission
fails.)
⑧ When ABS receives SBC request successfully, ABS grants UL bandwidth for next transmission of
AMS after sending SBC response.
⑨ AMS performs authentication and key exchanges. AMS starts a bandwidth grant timer after AMS sends
HARQ ACK and monitors A-A-MAP IE for a specific time interval whether an unsolicited bandwidth
is assigned. If ABS allocates UL bandwidth, AMS stops the timer and sends UL data.
⑩ After completion of authentication and key exchanges, AMS negotiates remaining capabilities and
performs registration. Similar operation (described above) can be applied during authentication message
exchanges.
 Bandwidth Grant AMS Timer
Timer defined by AMS to monitor an unsolicited bandwidth grant without issuing bandwidth request.
When ABS notifies AMS of an unsolicited bandwidth grant, AMS may start a bandwidth grant timer
and monitor UL bandwidth for a specific time interval. ABS should grant bandwidth to AMS for a UL
transmission in the form of a data grant either after ABS receives HARQ ACK or after maximum
HARQ retransmission fails. As a result, as long as the AMS attempts to access the ABS, the ABS may
allocate an unsolicited UL grant to enable AMS to transmit MAC messages. This timer is only issued
when ABS sends an unsolicited bandwidth grant indicator.
Fig 1 shows proposed fast network entry procedure:
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IEEE C802.16m_09/0993
AMS
ABS
A-Preamble
SFH
Initial ranging code
AAI_RNG RSP
AAI_RNG-REQ
AAI_RNG-RSP
Start Bandwidth grant timer
Unsolicited UL
Grant
( Unsolicited Bandwidth Grant Indicator)
HARQ ACK
Stop Bandwidth grant timer
Start Bandwidth grant timer
Stop Bandwidth grant timer
Unsolicited Bandwidth Allocation
Transmission Fail (AAI_SBC-REQ)
Expiration of HARQ
retransmission
-> UL Grant
HARQ NACK
Unsolicited Bandwidth Allocation
ReTransmission Success (AAI_SBC-REQ)
AAI_SBC-RSP
Unsolicited UL
Grant
Start Bandwidth grant timer
HARQ ACK
Stop Bandwidth grant timer
Unsolicited Bandwidth Allocation
AAI_PKM-REQ
Fig 1. Usage of Bandwidth Grant AMS timer
5. Text proposal for the 802.16m amendment
========================Start of Proposed Text==================================
15.2 Medium access control
15.2.X Fast Network Entry
For the purpose of expediting Network Entry of the AMS, ABS may allocate bandwidth for transmission
opportunity for the AMS, i.e., an unsolicited UL allocation for transmission of each MAC message during
network entry.
Regardless of receiving a request from AMS, ABS may place an unsolicited bandwidth grant indicator in the
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IEEE C802.16m_09/0993
AAI-RNG-RSP message during network entry and allocate UL bandwidth for message (re)transmission from
AMS throughout the network entry procedure. AMS starts a bandwidth grant AMS timer either after the AMS
sends HARQ ACK or after maximum HARQ retransmission fails and monitors the A-A-MAP IE for possible
bandwidth allocation. AMS may be assigned with continuous transmission opportunities within every
bandwidth grant interval. When the Bandwidth Grant AMS timer expires without a UL bandwidth assignment,
AMS may perform contention based bandwidth request for retransmission.
Bandwidth Grant AMS Timer
During network entry, ABS may allocate an UL bandwidth for (re)transmission of MAC messages without a
bandwidth request from AMS.
AMS may initially start the Bandwidth Grant AMS timer on receipt of AAI_RNG-RSP with an unsolicited
bandwidth grant indicator. AMS should start the Bandwidth Grant AMS timer either after the AMS sends
HARQ ACK or after maximum HARQ retransmission fails and should stop it on assignment of a UL bandwidth.
When the Bandwidth Grant AMS timer expires without a UL bandwidth assignment, AMS may perform
contention based bandwidth request for (re)transmission
As a result, as long as the AMS attempts to access to the ABS, the AMS may have opportunities for message
(re)transmission without the need of requesting bandwidth.
============================== End of Proposed Text ==============================
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