User's Manual

Appendix D - Application Development _________________________ Boomer-III User Manual & Integrator’s Guide
Copyright Wavenet Technology © October 2003 120 BM310012WT04
Conserve battery life when out-of-range
When all channels (from both dynamic and static channel lists) are
scanned and network contact is not established, the wireless modem
enters a scan-delay state. The scan-delay starts at one second and
doubles on each scan cycle failure, to a maximum of 255 seconds
between scan cycles. This delay time is reset to one second by
establishing a network connection or by power-cycling the device.
Re-establish network contact following inbound SDU failure (no
response) and poor RF RSSI or signal quality
Any wireless modem experiencing a no-response inbound SDU failure
and either with RSSI or quality below the exit threshold level must re-
establish network contact. If unable to re-establish network contact, the
modem indicates an out-of-range event. When network contact is re-
established, the wireless modem indicates an in-range event. The client
application then resubmits any queued inbound SDU last rejected with
an out-of-range response.
Re-establish network contact due to loss of outbound channel
The wireless modem attempts to re-establishes network contact
following loss of the outbound channel. If unable to re-establish
network contact, the modem indicates an out-of-range event, and
procedures to re-establish network contact are initiated. When network
contact is re-established, the wireless modem indicates an in-range
event. The client application then resubmits any queued inbound SDU
last rejected with an out-of-range response.
Seek and locate the preferred alternate channel when the existing
channel degrades to a marginal level
When the existing RF channel degrades to a marginal (but still usable)
level, the device periodically listens to neighbouring channels to
determine whether a preferred alternate channel exists. This action
occurs when the device would otherwise be sleeping, to prevent impact
to the device’s synchronized-receive capability with the network.
To be considered, a preferred alternate channel must meet the
minimum channel entry criteria and be 5 dBm better than the current
channel. If located, a full channel acquisition is performed to verify all
other aspects of the alternate channel before registering to the new
channel. This preferred-channel pre-roam algorithm is performed at
intervals that increase exponentially and with identical reset conditions.
See “Conserve battery life when out-of-range” above.