User's Manual

User Manual
3000 SERIES 3
rd
GENERATION ACTIVE RFID
Energy-Efficient The network is energy-efficient. Nodes maximize their sleep time - and
therefore increase battery lifetime - by communicating only at certain
tightly synchronized time intervals. An important reason for this energy-
efficiency stems from the underlying network principles applied in
Ambient networks. It is a combination of Time Division Multiple Access
(TDMA) and Carrier Sense Multiple Access (CSMA) which enable the
nodes to use their radios in the most energy-efficient manner.
Robust As the network is multi-hop, it enables you to create redundancy in your
networks by providing several paths between different nodes. Whenever a
single MR fails, there are still other routes available towards the GW. This
approach provides a high degree of robustness to the system.
Secure Various security mechanisms are in place that protect sensitive
information flowing through your networks. One of these mechanisms, for
example, is the use of a network key; by setting such a key all
communication is encrypted and only interpretable by trusted parties that
have the appropriate security keys.
Localization An Ambient network has integrated peripherals and network interactions
that provide the means for a node to locate itself. As SPs do not need to
register with the network, they can observe beacon messages that are
being sent and derive a position estimate from the information gathered.
11.2.3 Network Size
Network size is an important aspect when planning a deployment for a certain application and
considering the desired behaviour of the SmartPoints. Effectively, the size of the network is related
to the two distinctive layers that exist in a network; on one hand there is the infrastructure which
makes up the communication backbone and provides the appropriate coverage, on the other hand
there are the SmartPoints whose number is only limited by the number of beacon messages they
consume.
The size of the infrastructure is fixed and determined by the type of GW used.
The number of SPs is dependent on the reporting frequency of the SPs and the number of MRs. Each
GW and MR transmit certain beacon messages. These beacon messages are used by SPs to
communicate with the infrastructure and locate themselves. By default, a GW and MR transmit 2 of
such beacons per second. They can be configured to transmit 4 of those, if deemed necessary, but the
SP load needs to be taken into account.
Consider this example; there are 15 MRs in a network that is build up using a GW3000. The SP300T
reports every 5 minutes by default. Then the absolute maximum number of SmartPoints is 5 x 60 x 2
x (15+1) = 9600. However; messages from SPs can collide and message loss will occur. Also, if all SPs
are in range of just a few MRs, there will be a network unbalance and even more collisions will
occur. The network architecture has various means to handle these unbalanced loads by various
mechanisms and congestion control, ensuring maximum achievable performance in the worst of
scenarios.
Adding more MRs to the nework will, in most cases' solve the aforementioned problem. Contact
[e-mail] for more information on this topic.
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