Mechanism for self-coexistence of multiple HR cells for 802.16n OFDMA Network
Document Number:
IEEE S802.16n-11/0180
Date Submitted:
2011/09/20
Source:
Ming-Tuo Zhou 1 , Hoang Vinh Dien 1 , Liru Lu 1 ,
Xin Zhang 1 , Masayuki Oodo 2 ,
Hiroshi Harada 1,2
E-mail: mingtuo@nict.com.sg
National Institute of Information and
Communications Technology
Re:
*< http://standards.ieee.org/faqs/affiliationFAQ.html
>
Call for Comments for 802.16n AWD
Base Contribution:
IEEE 802.16n-11/0015
Purpose:
To propose AWD text about mechanism of self-coexistence for 802.16n OFDMA network
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.
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Frame Contention
Self-Coexistence Mode of
Data Services
Internal Demands for
Frames
No
Start
(HR-station Discovered
Adjacent HR Cell)
Channel Acquisition
Channel
Successfully
Accquired?
Yes
Normal Mode of Data
Service
External Demands for Frames
• Appropriate method should be adopted when an HR station finds a neighbor HR network on its operating channel
• The HR network first tries to acquire another available frequency channel if exists
• If it fails to do so, frame contention will be performed, for purpose to allocate frames among the co-existence HR networks
• Frame contention can also happen if an HR network needs more resource, or an HR network requests to do so

• An HR station discovers an adjacent HR cell with the method.
The network discovery includes discovering:
– Self-coexistence zone reservation of a neighboring HR cell;
– Frame reservation patterns of the neighboring HR cells on specific channels (this information can be obtained from received coexistence beacon packets).
• In the case that an HR-MS or HR-RS discovers neighboring
HR cell, it reports the network discovery information to its serving HR-BS.

• An HR network may schedule scanning wireless medium on other frequency channels are is aware of the availability of other frequency channels
• The serving HR network may try to acquire available frequency channel if exists

• If the serving HR-BS successfully acquires another frequency channel, it goes to the normal mode of data service operations on the acquired channel. Otherwise, it performs frame contention.

• During operation of normal mode, a serving HR-BS may receive demands from a neighboring HR cell for sharing channel.
• When this happens, it tries to find an empty frequency channel. If it finds an empty channel, it moves its service to the channel and operates in normal mode of data service.
Otherwise, the serving HR-BS performs frame contention on its operation channel.

• In self-coexistence mode, a serving HR-BS may need to reinitiate wireless medium scanning for channel acquisition if it receives internal demand for more spectrum resource or external demand for sharing channel. In this case, it goes to step S2.

• Frame Contention Request (HR-FC-REQ) – carries request information of a requesting HR-BS, including index of the targeted frames within a self-coexistence cycle;
• Frame Contention Response (HR-FC-RSP) – carries contention result information of each requested frame;
• Frame Contention Acknowledgement (HR-FC-ACK) – carriers confirmation or not of acquisition of each of the requested frame;
• Frame Contention Release (HR-FC-REL) – carries information of release or not of each frame within a selfcoexistence cycle.

Requesting
HR-BS
HR-FC-REQ time
HR-FC-RSP
HR-FC-ACK
HR-FC-REL
Requested
HR-BS

Start
Identify target
Frame Contention
Destinations (FCD)
Choose one from remaining FCDs
Select frames for contention from ones occupied by this
FCD and construct
HR-FC-REQ
Send out HR-FC-
REQ and start timer T
1
Received
HR-FC-RSP from the selected FCD before T
1 expires?
Yes
Send out HR-FC-
ACK if any frames granted
No
Sufficient frames?
Yes
No
Yes
Are there remaining
FCDs?
No
End
• Frame contention source (FCS) is an
HR cell that intends to acquire frames by contention.
• An FCS monitors frame occupancies by analyzing received self-coexistence beacons. When it needs to contend for frames, it identifies target Frame
Contention Destinations (FCDs), which are HR cells around it and carries out the procedure of frame contention based on flow shown on left.
• In above, once an FCS receives an HR-
FC-REL addressed to it, it occupies the frames granted to it from next selfcoexistence cycle and updates its frame occupancy MAP.

Start
Received HR-FC-
REQ messages from FCSs
Are remaining frames it occupied more than minimum frames it requires?
Yes
Identify all FCSs of the first frame being requested among the remaining frames.
Randomly selects one from {all FCSs of this frame, FCD itself}. If the one selected is not the
FCD itself, it grants the frame to the selected FCS.
Construct HR-FC-
RSP and sends it out.
End
• Frame contention destination (FCD) is an
HR cell that is acquired by a frame contention source for frames.
• When an FCD receives an HR-FC-REQ, it checks the number of frames it occupied. If the number is not more than a minimum number it requires, it doesn’t carry out frame contention. Otherwise, it identifies all FCSs of the first frame in contention. It decides to grant and FCS by a random process.
• When an FCD receives HR-FC-ACK from an FCS, it releases the corresponding frames by sending out
HR-FC-REL, and it updates its frame occupancy MAP from next selfcoexistence cycle.

• See IEEE C80216n-11/0180