Openmoko Bug #1972: Wifi interferes with Bluetooth
Openmoko Public Trac
bugs at docs.openmoko.org
Mon Sep 8 22:50:27 CEST 2008
#1972: Wifi interferes with Bluetooth
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Reporter: Mercury | Owner: openmoko-devel
Type: defect | Status: new
Priority: normal | Milestone:
Component: unknown | Version:
Severity: normal | Resolution:
Keywords: bluetooth, wifi, interference, a2dp | Blockedby:
Reproducible: | Blocking:
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Comment(by werner):
If the throughput of WLAN is reduced by the same ratio as the throughput
that
BT gets, and vice versa, then things should be okay. E.g., if you measure
the
throughput of each alone as WLAN_solo and BT_solo, and again with both
active
as WLAN_shared and BT_shared, you should roughly obtain
~100% <= WLAN_shared/WLAN_solo+BT_shared/BT_solo <= ~200%
for any coexistence solution.
What coexistence in its most primitive form (and I think that's what we
have)
does is to make sure that they don't send at the same time. So they don't
create situations where both try to occupy the same frequency, resulting
in
neither being heard, and not only this transmission being lost, but also
more
time lost to recovery.
Here's a good introduction to the issue:
http://focus.ti.com/pdfs/vf/bband/coexistence.pdf
If you do the calculation from above on the data in that paper for a
distance
of 50ft, you obtain roughly 25% for WLAN and 10% for BT, resulting in 35%
bandwidth utilization for uncoordinated sharing. (Under, I presume,
otherwise
ideal conditions.)
- Werner
--
Ticket URL: <https://docs.openmoko.org/trac/ticket/1972#comment:3>
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