Transcript ARQ throughputs

ARQ for IEEE 802.16m
Document Number: IEEE C802.16m-09/0512
Date Submitted:
2009-03-02
Source:
Muthaiah Venkatachalam ([email protected])
Xiangying Yang
Aran Bergman
Intel Corporation
Intel Corporation
Intel Corporation
Venue: Re: TGm Call for Contributions and Comments on AWD: C802.16m-09/0012 for Session 60 in Vancouver, BC for UMAC/ARQ
Base Contribution: None
Purpose: Discussion and approval of the proposal into the IEEE 802.16m AWD
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Worst case of ARQ tpt
• Assume 16e ARQ
• 18x6 PRU => 96 data tones
• QPSK1/2 is the worst case data MCS =>
12Bytes/PRU
• Minimum ARQ block size in 16m = 12B
• Worst case tpt = 12B*1024/RTT
• If RTT = 20msec, which is worst case
– tpt = 5 Mbps
IMT.TECH Avg cell spectral
efficiency
Test environment **
Indoor
Downlink (b/s/Hz/cell)
Uplink (b/s/Hz/cell)
3
2.25
Microcellular
2.6
1.80
Base coverage urban
2.2
1.4
High speed
1.1
0.7
ARQ Avg case throughputs for 16m
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20 Mhz channel
DL tpt = 3*20 = 60Mbps
UL tpt = 2.25*20 = 45Mbps
If the DL tpt can be met, then the UL tpt
can also be met.
• Worst case assumption: total system tpt is
gobbled up by 1 user!
ARQ proposal for 16m
• With 11bit BSN, worst case ARQ tpt is
5Mbps
• With 15bit BSN, worst case ARQ tpt is
5*(2^4) = 80 Mbps
– This meets the IMT.TECH avg tpt
requirements for DL (and UL)
• Intel’s proposal for 802.16m ARQ:
– Keep 802.16e ARQ intact
– Use max of 15 bit BSN.
IMT.TECH Peak throughput
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Error free conditions.
40Mhz channel
DL: 15 bits/s/Hz @PHY layer
UL: 6.75 bits/s/Hz @PHY layer
25% MAC overhead
DL tpt at ARQ layer = 450Mbps
UL tpt at ARQ layer = 202 Mbps
If the DL tpt can be met, then the UL tpt can also be met.
Worst case assumption: total system tpt is gobbled up by
1 user!
IMT peak tpt with Intel’s ARQ
proposal
• IMT peak tpt assumes error free
conditions.
• Max block size that can be used in error
free conditions = 1024B.
• With 1024B block, 15bit BSN and 20msec
RTT,
– ARQ tpt = 6.8Gbps!!!
• Conclusion: Let us not change 16e ARQ
unless we really need to!