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EBS30
Specifications Manual
9
7. Radio Specifications
Parameter
Min
Typ
Max
Unit
Remarks
Receiver sensitivity
-97
-89
dBm
Over the entire temp. and
operating voltage range
Nominal output power
-3
4.5
7
dBm
Frequency
2394
2507
MHz
Over the entire temp. and
operating voltage range
Transfer rate
250Kbit/s
RSSI range
100
dB
Signal strength indication
that can be reported to the
base station
7.1. Protocol
Modified 802.15.4 (Physical layer and Media Access Control layer).
7.1.1.
The physical layer
The physical layer (PHY) provides the data transmission service, as well as the
interface to the physical layer management entity, which offers access to every layer
management function and maintains a database of information on related personal
area networks. Thus, the PHY manages the physical RF transceiver and performs
channel selection and energy and signal management functions. It operates on the
above mentioned frequency band. The PHY layer is 100% compliant and is based on
direct sequence spread spectrum (DSSS) technique with a transfer rate of 250 kbit/s.
7.1.2.
The medium access control layer
The medium access control (MAC) layer enables the transmission of MAC frames
through the use of the physical channel. Besides the data service, it offers a
management interface and itself manages access to the physical channel. It also
controls frame validation, guarantees time slots and handles node associations.
Finally, it offers hook points for secure services. The EE200 does not make use of the
optional network beaconing, instead it used a polling mechanism to increase power
efficiency. Some changes are made to the standard to allow for more efficient data
frames and better power efficiency, especially when nodes are not connected to a
base station.
7.2. Security
The 802.15.4 standard 128-bit AES encryption is supported. A secure method for key
management is implemented as well. The encryption is optional though and can be
configured. By default the radio traffic is unencrypted.
