1. Bandwidth Request Indicator
IEEE Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-08/986r1
Date Submitted:
Source:
Xiaobing Leng, Jimin Liu, Gang Shen, Kaibin Zhang, Dongyao Wang, Shan Jin Voice:
Alcatel Shanghai Bell
388#, Ningqiao Road, Pudong Jinqiao
Shanghai, , P.R. China
Venue:
[802.16m] [16jm] Session #57, September, 2008
Re:
PHY: SDD Session 56 Cleanup; in response to the TGm Call for Contributions and Comments m-08/033 for Session 57
Purpose:
To propose a Bandwidth Request Indicator (BRI) scheme which can implicitly indicate the request size
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2. Background
It is defined in IEEE m-08/003r4 (SDD) to use a quick 3-step (step 1,4 and 5) bandwidth request procedure
Bandwidth Request Indicator (BRI) is still not defined for carrying additional bandwidth request information BS MS
Bandwidth Request Indicator 1
UL grant for BW-REQ message 2
BW-REQ message 3 BS MS
UL grant 4
UL scheduled transmission with optional piggybacked bandwidth request 5

3. Introduction of the BRI proposal
Reserve several ranging/BR slots in random access channel as non-contention based bandwidth request channel
BRI is a preassigned ranging code in a special slot of non-contention based bandwidth request channel
The ranging code preassignment will keep certain rule to avoid confliction
MS may be allocated several BRIs to carry additional bandwidth request information, e.g.
Several combined BRIs can indicate different BR size levels
Advantages
Uniform ranging codes for ranging, contention based BR and non-contention based BR
Easy to implement

4. Non-contention based bandwidth request channel
Random access channel for transmitting BRI is divided into
Contention based random access channel
Non-contention based random access channel
Two same ranging codes should not exist in a same BR slot
Number of ranging codes in a BR slot should be less than a threshold to guarantee correct code detection
N1: Symbol number for a ranging code
N2: Subchannel number for ranging code
Contention based
Ranging/BR opportunity slot 1 2
Empty 3 4 5 6 7 8 N2
subchannels 1 2
N1 OFDMA symbols
<N1 OFDMA symbols
Non-contention based ranging/BR opportunity slot

5. UL scheduled transmission with optional piggybacked bandwidth request
Combined BRIs
Several BRIs can be combined to indicate more bandwidth request information, e.g. 3 BRIs can indicate 8 request sizes
The BR size corresponding to each BRI combination is predefined between BS and MS
MS can select and send combined BRIs according to current buffer size
BRI 1
BRI 2
BRI 3
Request sizes
No request 1
Size 1
Size 2
Size 3
Size 4
Size 5
Size 6
Size 7 BS MS
Bandwidth Request Indicators (BRIs) 1
UL grant with a special size 4
UL scheduled transmission with optional piggybacked bandwidth request 5
0: MS doesn’t transmit BRI;
1: MS transmits BRI

6. Proposed Text Change
Change the following text in SDD (IEEE m-08/003r4) section – Bandwidth request channel as indicated
Contention based or non-contention based random access is used to transmit a bandwidth request indicator on this control channel. For non-contention based random access, a preassigned ranging code in a special bandwidth request slot represents a bandwidth request indicator. A MS or a connection may be allocated one or several bandwidth request indicators. To support different levels of QoS, the bandwidth request channel provides a mechanism for prioritized bandwidth requests. Inclusion of addition information in a bandwidth request indicator such as bandwidth request size, MS-ID, flow identifier, uplink transmit power report and CINR report is FFS.
The random access bandwidth request procedure is described in Figure 35. A 5-step regular procedure (step 1 to 5) or an optional quick access procedure (step 1,4 and 5) may be supported concurrently. Step 2 and 3 are used only in 5-step regular procedure. In step 1, MS sends a bandwidth request indicator or multiple bandwidth request indicators that may indicate information such as MS addressing and/or request size (FFS) and/or uplink transmit power report (FFS), and the BS may allocate uplink grant based on certain policy. Multiple bandwidth request indicators can be combined to indicate the bandwidth request size. The 5-step regular procedure is used independently or as fallback mode for quick access procedure. The MS may piggyback additional BW-REQ information along with user data during uplink transmission (step 5).