Image Processing Reference
In-Depth Information
Communication cycle
Symbol window
Static segment
Dynamic segment
NIT
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19
A1
C1
t
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19
A1
B1
C2
t
(a)
Communication cycle
Symbol window
Static segment
Dynamic segment
NIT
1
2
3
4
56789 0 1 2 3 4 5 6
A1
C1
D1
t
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19
A1
B1
C2
t
(b)
FIGURE .
FlexRay dynamic segment.
the media access control can be guaranteed and thus silence is required. Since this duration has to
be subtracted from net bandwidth, this duration is kept as small as possible. The minimum length
is largely determined by the maximum deviation between the local clocks after one communication
cycle. he duration of the network idle time is a global parameter that has to be consistent between
all controllers in a network.
While at least a minimal static segment and the network idle time are mandatory parts of a com-
munication cycle, the symbol window and the dynamic segment are optional parts. This result in
basically three reasonable configurations (see Figure .):
Pure static configuration, which contains only static slots for transmission. In order to
enable clock synchronization, the static segment must consist of at least two slots, which
are owned by different controllers. If a fault-tolerant clock synchronization should be
maintained, the static segment must comprise at least four static slots.
Mixed configuration with a static segment and a dynamic segment, where the ratio
between static bandwidth and dynamic bandwidth can vary in a broad range.
Finally, a pure dynamic configuration with all bandwidth assigned to dynamic commu-
nication. his configuration also requires a so-called degraded static segment, which has
two static slots.
 
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