System Implementation and Evaluation of an Energy Efficient UWB-Based MAC Protocol for Wireless Body Area Networks - Ultra Wideband Wireless Body Area Networks - page 134

1

0.1

0.01

1E-3

1E-4

1E-5

1E-6

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Distance (m)

Fig. 6.16 Experimental BER variation of Scenario 4

6.6.1.4 BER Analysis for Scenario 4

Scenario 4 follows the same experimental procedure as in Scenario 1 except for
the fact that sensor nodes are placed on two users such that each user carries two
on-body sensor nodes. Both users are placed at equal distances from coordinator
node. Figure 6.16 presents the BER variation for different separation distances.
BER variation for this experiment behaves in a similar pattern to that of Scenario
1. The scheduled nature of the data transmission in dual-band MAC protocol helps
to avoid data collisions between sensor nodes that belong to the same user as well
as sensor nodes that belong to different users. Hence, BER for both Scenario 1 and
Scenario 2 show similar behavior.

6.6.2 Initialization Delay of Sensor Nodes

Sensor initialization delay represents the time taken for a sensor node to register in
the communication system and starts data communication. A sensor node goes
through the procedure shown in Fig. 6.17 during a sensor initialization stage. This
sensor initialization procedure is further described under Chap. 3 . During the