1. Jung Yee, IceFyre Semiconductor
January 2002
doc.: IEEE /064r0
January 2002
802.11g PAR issues with D1.1
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

2. January 2002
doc.: IEEE /064r0
January 2002
802.11g PAR
From document /114r3
Purpose: To develop a new PHY extension to enhance the performance and the possible applications of the b compatible networks by increasing the data rate achievable by such devices
Section 12: The new proposed b extension shall be interoperable with the existing b standard that operates in the 2.4GHz band.
Section 16: The new extension shall implement all mandatory portions of the IEEE b PHY standard.
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

3. Spectral Mask Comparison
January 2002
doc.: IEEE /064r0
January 2002
Spectral Mask Comparison
802.11b
802.11a
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

4. Spectral Mask Analysis
January 2002
doc.: IEEE /064r0
January 2002
Spectral Mask Analysis
Downbanded a signal will violate GHz emissions limits
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

5. Interference Analysis
January 2002
doc.: IEEE /064r0
January 2002
Interference Analysis
802.11g and b systems will both experience Co-Channel Interference (CCI)
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

6. Interference Analysis contd
January 2002
doc.: IEEE /064r0
January 2002
Interference Analysis contd
From document /142, slide “Loss in SNR with SIR=10dB”
802.11g systems will degrade existing b systems
802.11g systems will have poor performance
Signal
Barker-2
CCK-11
PBCC-11
PBCC-22
OFDM-24
Interferer
2.5 dB
2.6 dB
1.2 dB
3.3 dB
5.6 dB
0.6 dB
2.7 dB
3.2 dB
5.9 dB
1.1 dB
5.7 dB BT
0.0 dB
1.9 dB
0.5 dB
N/A
0.7 dB
4.2 dB
1.3 dB
5.0 dB
>8.0 dB
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

7. January 2002
doc.: IEEE /064r0
January 2002
ESS considerations
No provisions for roaming between an b AP and and g AP
No provisions for STA modulation mode changes while roaming in an g system
QoS cannot be preserved while roaming
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

8. IBSS considerations 802.11b CCA will not detect OFDM short symbol
January 2002
doc.: IEEE /064r0
January 2002
IBSS considerations
802.11b CCA will not detect OFDM short symbol
802.b STA performance degraded in the presence of g STA
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

9. BSS considerations 802.11g AP must support all modulation modes
January 2002
doc.: IEEE /064r0
January 2002
BSS considerations
802.11g AP must support all modulation modes
OFDM has longer processing delay than CCK
QoS (delay, jitter) violated by mix-mode operation
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor

10. January 2002
doc.: IEEE /064r0
January 2002
802.11g-D1.1 violates PAR
802.11g violates emissions restrictions in the GHz band
802.11b networks degraded by g networks
802.11g networks will have poor performance
Standalone cells will see improved performance
The draft will not ensure e QoS functionality (MAC violation)
Jung Yee, IceFyre Semiconductor
Jung Yee, IceFyre Semiconductor